exudates and Dengue

A systematic literature review was conducted to assess the epidemiology and economic burden of dengue in Malaysia.. Embase, MEDLINE, Evidence-Based Reviews databases, and gray literature sources were searched for English and Malay studies and surveillance reports on the epidemiology (between 2012 and 2019) and costs (between 2009 and 2019) of dengue in Malaysia. Independent screening of titles/abstracts, followed by full texts was performed using prespecified criteria.. A total of 198 publications were included (55 peer-reviewed and 143 gray literature). Dengue incidence has been increasing in recent years, with 130,101 cases (dengue fever 129,578 cases; dengue hemorrhagic fever 523 cases) reported in 2019, which is the highest since 2012. All dengue virus serotypes co-circulated between 2004 and 2017, and major outbreaks occurred in a cyclical pattern, often associated with a change in the predominant circulating serotype. Economic impacts are substantial, including the societal impact of lost work (7.2-8.8 days) and school days (3.2-4.1 days) due to dengue.. The rising incidence and high cost of dengue, coupled with overlapping diseases, will likely result in further pressures on the healthcare system. To appropriately mitigate and control dengue, it is critical to implement integrated strategies, including vaccination, to reduce the burden of dengue.

Topics: Dengue; Disease Outbreaks; Humans; Incidence; Malaysia; Serogroup

This review provided a systematic overview of the questionnaire-related dengue studies conducted in Malaysia and evaluated their reliability and validity used in the questionnaires. An extensive literature search was conducted using various electronic databases, including PubMed, EMBASE, Medline, and ScienceDirect. Systematic reviews and meta-analysis (PRISMA) were selected as the preferred item reporting method. Out of 88 identified dengue-related, 57 published from 2000 to April 2020 met the inclusion criteria and were included. Based on the meta-analysis, a poor mean score was obtained for knowledge (49%), attitude (44%), and preventive practice (55%). The study showed that the level of knowledge on cardinal signs and modes of transmission for dengue virus were highest among health care workers, followed by students (international and local) and lastly community residents. In treatment-seeking behaviours, only half of the respondents (50.8%) would send their child to the nearest health clinics or hospitals when a child became restless or lethargic. The acceptance rate for dengue vaccine, bacteria (Wolbachia), as a vector for dengue control and self-test diagnostic kit for dengue showed considerably high (88.4%, 70%, and 44.8%, respectively). Health belief model (HBM) constructs, such as perceived barriers, perceived severity, perceived susceptibility, self-efficacy, and perceived benefit influence prevention practices. Lastly, only 23 articles (40.3%) had piloted or pretested the questionnaire before surveying, in which three reported Cronbach's alpha coefficient (0.70-0.90). A need for active participation of communities and healthcare personnel, promotion of awareness, and safe complementary medicines, as well as assessment of psychometric properties of questionnaire use in dengue surveys in Malaysia, in order for assessing dengue reliably and valid.

Topics: Child; Dengue; Health Knowledge, Attitudes, Practice; Humans; Malaysia; Reproducibility of Results; Surveys and Questionnaires

Dengue is a climate-sensitive infectious disease. Climate-based dengue early warning may be a simple, low-cost, and effective tool for enhancing surveillance and control. Scientific studies on climate and dengue in local context form the basis for advancing the development of a climate-based early warning system. This study aims to review the current status of scientific studies in climate and dengue and the prospect or challenges of such research on a climate-based dengue early warning system in a dengue-endemic country, taking Malaysia as a case study.. We reviewed the relationship between climate and dengue derived from statistical modeling, laboratory tests, and field studies. We searched electronic databases including PubMed, Scopus, EBSCO (MEDLINE), Web of Science, and the World Health Organization publications, and assessed climate factors and their influence on dengue cases, mosquitoes, and virus and recent development in the field of climate and dengue.. Few studies in Malaysia have emphasized the relationship between climate and dengue. Climatic factors such as temperature, rainfall, and humidity are associated with dengue; however, these relationships were not consistent. Climate change projections for Malaysia show a mounting risk for dengue in the future. Scientific studies on climate and dengue enhance dengue surveillance in the long run.. It is essential for institutions in Malaysia to promote research on climate and vector-borne diseases to advance the development of climate-based early warning systems. Together, effective strategies that improve existing research capacity, maximize the use of limited resources, and promote local-international partnership are crucial for sustaining research on climate and health.

Topics: Biomedical Research; Climate; Communicable Disease Control; Dengue; Forecasting; Humans; Malaysia; Risk Factors; Weather

Dengue infection is the fastest spreading mosquito-borne viral disease, which affects people living in the tropical and subtropical countries. Malaysia had large dengue outbreaks in recent years. We aimed to study the demographics and clinical characteristics associated with dengue deaths in Malaysia.. We conducted a retrospective review on all dengue deaths that occurred nationwide between 1st January 2013 and 31st December 2014. Relevant data were extracted from mortality review reports and investigational forms. These cases were categorized into children (<15 years), adults (15-59 years) and elderly (≥60 years) to compare their clinical characteristics.. A total of 322 dengue deaths were reviewed. Their mean age was 40.7±19.30 years, half were females and 72.5% were adults. The median durations of first medical contact, and hospitalization were 1 and 3 days, respectively. Diabetes and hypertension were common co-morbidities among adults and elderly. The most common warning signs reported were lethargy and vomiting, with lethargy (p = 0.038) being more common in children, while abdominal pain was observed more often in the adults (p = 0.040). But 22.4% did not have any warning signs. Only 34% were suspected of dengue illness at their initial presentation. More adults developed severe plasma leakage (p = 0.018). More than half (54%) suffered from multi-organ involvement, and 20.2% were free from any organ involvement. Dengue deaths occurred at the median of 3 days post-admission. Dengue shock syndrome (DSS) contributed to more than 70% of dengue deaths, followed by severe organ involvement (69%) and severe bleeding (29.7%).. In Malaysia, dengue deaths occurred primarily in adult patients. DSS was the leading cause of death, regardless of age groups. The atypical presentation and dynamic progression of severe dengue in this cohort prompts early recognition and aggressive intervention to prevent deaths.. National Medical Research Registry (NMRR, NMRR-14-1374-23352).

Topics: Adolescent; Adult; Aged; Child; Child, Preschool; Comorbidity; Demography; Dengue; Disease Outbreaks; Female; Hospitalization; Humans; Malaysia; Male; Middle Aged; Pneumonia; Retrospective Studies; Severe Dengue; Time Factors; Young Adult

A literature survey and analysis was conducted to describe the epidemiology of dengue disease in Malaysia between 2000 and 2012. Published literature was searched for epidemiological studies of dengue disease, using specific search strategies for each electronic database; 237 relevant data sources were identified, 28 of which fulfilled the inclusion criteria. The epidemiology of dengue disease in Malaysia was characterized by a non-linear increase in the number of reported cases from 7,103 in 2000 to 46,171 in 2010, and a shift in the age range predominance from children toward adults. The overall increase in dengue disease was accompanied by a rise in the number, but not the proportion, of severe cases. The dominant circulating dengue virus serotypes changed continually over the decade and differed between states. Several gaps in epidemiological knowledge were identified; in particular, studies of regional differences, age-stratified seroprevalence, and hospital admissions.. PROSPERO #CRD42012002293.

Topics: Age Distribution; Dengue; Dengue Virus; Humans; Malaysia; Seasons; Seroepidemiologic Studies; Serogroup; Sex Distribution; Socioeconomic Factors

Dengue represents a substantial burden in many tropical and sub-tropical regions of the world. We estimated the economic burden of dengue illness in Malaysia. Information about economic burden is needed for setting health policy priorities, but accurate estimation is difficult because of incomplete data. We overcame this limitation by merging multiple data sources to refine our estimates, including an extensive literature review, discussion with experts, review of data from health and surveillance systems, and implementation of a Delphi process. Because Malaysia has a passive surveillance system, the number of dengue cases is under-reported. Using an adjusted estimate of total dengue cases, we estimated an economic burden of dengue illness of US$56 million (Malaysian Ringgit MYR196 million) per year, which is approximately US$2.03 (Malaysian Ringgit 7.14) per capita. The overall economic burden of dengue would be even higher if we included costs associated with dengue prevention and control, dengue surveillance, and long-term sequelae of dengue.

Topics: Cost of Illness; Dengue; Humans; Malaysia

Dengue is the most common and widespread arthropod borne arboviral infection in the world today. It is estimated that there are at least 100 million cases of dengue fever (DF) annually and 500,000 cases of dengue hemorrhagic fever (DHF) which require hospitalization. In Malaysia, it has become a major public health problem. Malaysia recorded 19,544 dengue cases in 1997, the highest recorded since the disease was made notifiable in the country. Of 19,544 cases, 806 were DHF with 50 deaths. The objectives of this analysis were to describe the incidence of dengue fever and dengue hemorrhagic fever in Kota Bharu, Kelantan, Malaysia for the years 1998-2003 and to explore the characteristics of dengue fever and dengue hemorrhagic fever in Kota Bharu, Kelantan, Malaysia for years 1998-2003. A total of 4,716 dengue cases were notified involving 4,476 (94.9%) DF and 240 (5.1%) DHF cases, which increased though the years. The highest incidence was in January (701 or 14.9%), while the lowest was in May (188 or 4.0%). Forty percent of cases (n=1,890) were in the 15-29 year old group. The Majority were Malays (4,062 or 86.1%) and 2,602 or 55.2% were male. A total of 4,477 cases (95%) were local cases and 4,289 or 91% came from the urban area. For priority areas, 3,772 (80%) were from priority 1. More than half the cases had positive serology results. All symptoms occurred in more than 96% of cases and fever was the commonest (99.7%). The mean values for age, temperature, systolic and diastolic blood pressure (BP) were 27.8 +/- 15.4 years, 37.9 +/- 0.90 degrees C, 115 +/- 15.2 mmHg and 73 +/- 11.1 mmHg, respectively. The mean value for the time interval between the onset of symptoms and diagnosis, onset of symptoms and notification and time of diagnosis to notification were 5.1 +/- 2.3, 5.9 +/- 2.5 and 0.8 +/- 1.1 days, respectively. There were associations between the types of dengue and classification, area and priority area. Among the symptoms, the association was only seen in joint pain. The mean significant differences between DF and DHF were found in age and systolic blood pressure. The incidence of dengue in Kota Bharu is comparable to that in Malaysia. The increase in the number of cases needs to be addressed promptly with effective surveillance, prevention and control programs.

Topics: Adolescent; Adult; Dengue; Female; Humans; Incidence; Malaysia; Male; Medical Audit

Dengue fever, Dengue hemorrhagic fever and Dengue shock syndrome within the dengue complex is a sinister disease of great public health importance and continues to ravage children, young adults and the aged in Malaysia. The history of the disease is traced for over the years and the changing pattern of clinical presentation are noted. Various hospital based studies have been compared and the pathognomonic features of the disease in Malaysia are highlighted.

Topics: Adult; Child; Child, Preschool; Dengue; Female; Humans; Infant; Malaysia; Male

Topics: Animals; Dengue; Forecasting; Hemagglutination Tests; Humans; Immunoglobulin M; Immunologic Techniques; Malaysia

The historical background, epidemiology and changing pattern of clinical disease as seen in Malaysia is reviewed. The preliminary results of the longitudinal study of epidemiology of dengue in Malaysia is also presented. Studies led by Rudnick et al. over some 18 years have established that the disease is endemically transmitted by both Aedes aegypti and Aedes albopictus causing illnesses ranging from mild febrile episodes through classical dengue fever, dengue haemorrhagic fever and the dengue shock syndrome. The first epidemic occurred in 1962 in Penang, and the second major epidemic in 1974 in Selangor. From then on epidemics seem to occur every 4 years, i.e. 1978, and then in 1982. With increasing number of cases being seen from the end of 1985 and in 1986, and with the increasing numbers of positive virus isolates, another epidemic may occur this year. Though in the early years, mainly children were affected, recently more cases are being seen in 16-30 years age group. There is also a changing pattern in the clinical presentation of the cases. The clinician has to be aware of the various modes of presentation of this sinister disease. A high index of suspicion is needed for early diagnosis, as management is mainly symptomatic and there is no specific drug as yet to combat the shock and bleeding manifestations.

Topics: Adolescent; Child; Child, Preschool; Dengue; Female; Humans; Infant; Malaysia; Male

Topics: Aedes; Animals; Dengue; Female; Health Knowledge, Attitudes, Practice; Humans; Malaysia; Male; Mosquito Control; Mosquito Vectors; Population Surveillance; Viral Nonstructural Proteins

The COVID-19 pandemic placed an unprecedented overload on healthcare system globally. With all medical resources being dedicated to contain the spread of the disease, the pandemic may have impacted the burden of other infectious diseases such as dengue, particularly in countries endemic for dengue fever. Indeed, the co-occurrence of COVID-19 made dengue diagnosis challenging because of some shared clinical manifestations between the two pathogens. Furthermore, the sudden emergence and novelty of this global public health crisis has forced the suspension or slow-down of several research trials due to the lack of sufficient knowledge on how to handle the continuity of research trials during the pandemic. We report on challenges we have faced during the COVID-19 pandemic and measures that were implemented to continue the iDEM project (intervention for Dengue Epidemiology in Malaysia).. This randomized controlled trial aims to assess the effectiveness of Integrated Vector Management (IVM) on the incidence of dengue in urban Malaysia by combining: targeted outdoor residual spraying (TORS), deployment of auto-dissemination devices (ADDs), and active community engagement (CE). Our operational activities started on February 10, 2020, a few weeks before the implementation of non-pharmaceutical interventions to contain the spread of COVID-19 in Malaysia.. The three main issues affecting the continuity of the trial were: ensuring the safety of field workers during the interventions; ensuring the planned turnover of TORS application and ADD deployment and services; and maintaining the CE activities as far as possible.. Even though the pandemic has created monumental challenges, we ensured the safety of field workers by providing complete personal protective equipment and regular COVID-19 testing. Albeit with delay, we maintained the planned interval time between TORS application and ADDs services by overlapping the intervention cycles instead of having them in a sequential scheme. CE activities continued remotely through several channels (e.g., phone calls and text messages). Sustained efforts of the management team, significant involvement of the Malaysian Ministry of Health and a quick and smart adaptation of the trial organisation according to the pandemic situation were the main factors that allowed the successful continuation of our research.. Trial registration number: ISRCTN-81915073 . Date of registration: 17/04/2020, 'Retrospectively registered'.

Topics: COVID-19; COVID-19 Testing; Dengue; Humans; Malaysia; Pandemics

In common with many South East Asian countries, Malaysia is endemic for dengue. Dengue control in Malaysia is currently based on reactive vector management within 24 h of a dengue case being reported. Preventive rather than reactive vector control approaches, with combined interventions, are expected to improve the cost-effectiveness of dengue control programs. The principal objective of this cluster randomized controlled trial is to quantify the effectiveness of a preventive integrated vector management (IVM) strategy on the incidence of dengue as compared to routine vector control efforts.. The trial is conducted in randomly allocated clusters of low- and medium-cost housing located in the Federal Territory of Kuala Lumpur and Putrajaya. The IVM approach combines: targeted outdoor residual spraying with K-Othrine Polyzone, deployment of mosquito traps as auto-dissemination devices, and community engagement activities. The trial includes 300 clusters randomly allocated in a 1:1 ratio. The clusters receive either the preventive IVM in addition to the routine vector control activities or the routine vector control activities only. Epidemiological data from monthly confirmed dengue cases during the study period will be obtained from the Vector Borne Disease Sector, Malaysian Ministry of Health e-Dengue surveillance system. Entomological surveillance data will be collected in 12 clusters randomly selected from each arm. To measure the effectiveness of the IVM approach on dengue incidence, a negative binomial regression model will be used to compare the incidence between control and intervention clusters. To quantify the effect of the interventions on the main entomological outcome, ovitrap index, a modified ordinary least squares regression model using a robust standard error estimator will be used.. Considering the ongoing expansion of dengue burden in Malaysia, setting up proactive control strategies is critical. Despite some limitations of the trial such as the use of passive surveillance to identify cases, the results will be informative for a better understanding of effectiveness of proactive IVM approach in the control of dengue. Evidence from this trial may help justify investment in preventive IVM approaches as preferred to reactive case management strategies.. ISRCTN ISRCTN81915073 . Retrospectively registered on 17 April 2020.

Topics: Aedes; Animals; Dengue; Humans; Incidence; Malaysia; Mosquito Control; Mosquito Vectors; Randomized Controlled Trials as Topic

Platelet transfusion is common in dengue patients with thrombocytopenia. We previously showed in a randomized clinical trial that prophylactic platelet transfusion did not reduce clinical bleeding. In this study, we aimed to characterize the predictors and clinical outcomes of poor platelet recovery in transfused and nontransfused participants.. We analyzed patients from the Adult Dengue Platelet Study with laboratory-confirmed dengue with ≤20 000 platelets/μL and without persistent mild bleeding or any severe bleeding in a post hoc analysis. Poor platelet recovery was defined as a platelet count of ≤20 000/μL on Day 2. We recruited 372 participants from 5 acute care hospitals located in Singapore and Malaysia between 29 April 2010 and 9 December 2014. Of these, 188 were randomly assigned to the transfusion group and 184 to the control group.. Of 360 patients, 158 had poor platelet recovery. Age, white cell count, and day of illness at study enrollment were significant predictors of poor platelet recovery after adjustment for baseline characteristics and platelet transfusion. Patients with poor platelet recovery had longer hospitalizations but no significant difference in other clinical outcomes, regardless of transfusion. We found a significant interaction between platelet recovery and transfusion; patients with poor platelet recovery were more likely to bleed if given a prophylactic platelet transfusion (odds ratio 2.34, 95% confidence interval 1.18-4.63).. Dengue patients with thrombocytopenia who were older or presented earlier and with lower white cell counts were more likely to have poor platelet recovery. In patients with poor platelet recovery, platelet transfusion does not improve outcomes and may actually increase the risk of bleeding. The mechanisms of poor platelet recovery need to be determined.. NCT01030211.

Topics: Adult; Blood Platelets; Dengue; Humans; Malaysia; Platelet Transfusion; Prospective Studies; Singapore; Thrombocytopenia

In this paper, we will start off by introducing the classical Ross-Macdonald model for vector-borne diseases which we use to describe the transmission of dengue between humans and

Topics: Aedes; Animals; Basic Reproduction Number; Cities; Computer Simulation; Dengue; Epidemics; Humans; Malaysia; Mathematical Concepts; Models, Biological; Mosquito Control; Mosquito Vectors

Dengue is the commonest vector-borne infection worldwide. It is often associated with thrombocytopenia, and prophylactic platelet transfusion is widely used despite the dearth of robust evidence. We aimed to assess the efficacy and safety of prophylactic platelet transfusion in the prevention of bleeding in adults with dengue and thrombocytopenia.. We did an open-label, randomised, superiority trial in five hospitals in Singapore and Malaysia. We recruited patients aged at least 21 years who had laboratory-confirmed dengue (confirmed or probable) and thrombocytopenia (≤20 000 platelets per μL), without persistent mild bleeding or any severe bleeding. Patients were assigned (1:1), with randomly permuted block sizes of four or six and stratified by centre, to receive prophylactic platelet transfusion in addition to supportive care (transfusion group) or supportive care alone (control group). In the transfusion group, 4 units of pooled platelets were given each day when platelet count was 20 000 per μL or lower; supportive care consisted of bed rest, fluid therapy, and fever and pain medications. The primary endpoint was clinical bleeding (excluding petechiae) by study day 7 or hospital discharge (whichever was earlier), analysed by intention to treat. Safety outcomes were analysed according to the actual treatment received. This study was registered with ClinicalTrials.gov, number NCT01030211, and is completed.. Between April 29, 2010, and Dec 9, 2014, we randomly assigned 372 patients to the transfusion group (n=188) or the control group (n=184). The intention-to-treat analysis included 187 patients in the transfusion group (one patient was withdrawn immediately) and 182 in the control group (one was withdrawn immediately and one did not have confirmed or probable dengue). Clinical bleeding by day 7 or hospital discharge occurred in 40 (21%) patients in the transfusion group and 48 (26%) patients in the control group (risk difference -4·98% [95% CI -15·08 to 5·34]; relative risk 0·81 [95% CI 0·56 to 1·17]; p=0·16). 13 adverse events occurred in the transfusion group and two occurred in the control group (5·81% [-4·42 to 16·01]; 6·26 [1·43 to 27·34]; p=0·0064). Adverse events that were possibly, probably, or definitely related to transfusion included three cases of urticaria, one maculopapular rash, one pruritus, and one chest pain, as well as one case each of anaphylaxis, transfusion-related acute lung injury, and fluid overload that resulted in serious adverse events. No death was reported.. In adult patients with dengue and thrombocytopenia, prophylactic platelet transfusion was not superior to supportive care in preventing bleeding, and might be associated with adverse events.. National Medical Research Council, Singapore.

Topics: Adult; Dengue; Equivalence Trials as Topic; Female; Hemorrhage; Humans; Malaysia; Male; Middle Aged; Platelet Transfusion; Singapore; Thrombocytopenia; Treatment Outcome

Dengue induced acute kidney injury (AKI) imposes heavy burden of illness in terms of morbidity and mortality. A retrospective study was conducted to investigate incidence, characteristics, risk factors and clinical outcomes of AKI among dengue patients.. A total 667 dengue patients (2008-2013) were retrospectively evaluated and were stratified into AKI and non-AKI groups by using AKIN criteria. Two groups were compared by using appropriate statistical methods.. There were 95 patients (14.2%) who had AKI, with AKIN-I, AKIN-II and AKIN-III in 76.8%, 16.8% and 6.4% patients, respectively. Significant differences (P<0.05) in demographics and clinico-laboratory characteristics were observed between patients with and without AKI. Presence of dengue hemorrhagic fever [OR (95% CI): 8.0 (3.64–17.59), P<0.001],rhabdomyolysis [OR (95% CI): 7.9 (3.04–20.49)], multiple organ dysfunction OR (95% CI):17.9 (9.14–35.12), P<0.001], diabetes mellitus [OR (95% CI): 4.7 (1.12–19.86), P = 0.034], late hospitalization [OR (95% CI): 2.1 (1.12–19.86), P = 0.033] and use of nephrotoxic drugs [OR(95% CI): 2.9 (1.12–19.86), P = 0.006] were associated with AKI. Longer hospital stay (>3days) was also observed among AKI patients (OR = 1.3, P = 0.044) [corrected].Additionally, 48.4% AKI patients had renal insufficiencies at discharge that were signicantly associated with severe dengue, secondary infection and diabetes mellitus. Overall mortality was 1.2% and all fatal cases had AKI.. The incidence of AKI is high at 14.2% among dengue patients, and those with AKI portended significant morbidity, mortality, longer hospital stay and poor renal outcomes. Our findings suggest that AKI in dengue is likely to increase healthcare burden that underscores the need of clinicians' alertness to this highly morbid and potentially fatal complication for optimal prevention and management.

Topics: Acute Kidney Injury; Adolescent; Adult; Dengue; Female; Humans; Incidence; Length of Stay; Malaysia; Male; Middle Aged; Retrospective Studies

Dengue disease is a major public health problem across the Asia-Pacific region for which there is no licensed vaccine or treatment. We evaluated the safety and immunogenicity of Phase III lots of a candidate vaccine (CYD-TDV) in children in Malaysia.. In this observer-blind, placebo-controlled, Phase III study, children aged 2-11 years were randomized (4:1) to receive CYD-TDV or placebo at 0, 6 and 12 months. Primary endpoints included assessment of reactogenicity following each dose, adverse events (AEs) and serious AEs (SAEs) reported throughout the study, and immunogenicity expressed as geometric mean titres (GMTs) and distribution of dengue virus (DENV) neutralizing antibody titres.. 250 participants enrolled in the study (CYD-TDV: n=199; placebo: n=51). There was a trend for reactogenicity to be higher with CYD-TDV than with placebo post-dose 1 (75.4% versus 68.6%) and post-dose 2 (71.6% versus 62.0%) and slightly lower post-dose 3 (57.9% versus 64.0%). Unsolicited AEs declined in frequency with each subsequent dose and were similar overall between groups (CYD-TDV: 53.8%; placebo: 49.0%). Most AEs were of Grade 1 intensity and were transient. SAEs were reported by 5.5% and 11.8% of participants in the CYD-TDV and placebo groups, respectively. No deaths were reported. Baseline seropositivity against each of the four DENV serotypes was similar between groups, ranging from 24.0% (DENV-4) to 36.7% (DENV-3). In the CYD-TDV group, GMTs increased post-dose 2 for all serotypes compared with baseline, ranging from 4.8 (DENV-1) to 8.1-fold (DENV-3). GMTs further increased post-dose 3 for DENV-1 and DENV-2. Compared with baseline, individual titre increases ranged from 6.1-fold (DENV-1) to 7.96-fold (DENV-3).. This study demonstrated a satisfactory safety profile and a balanced humoral immune response against all four DENV serotypes for CYD-TDV administered via a three-dose regimen to children in Malaysia.

Topics: Antibodies, Neutralizing; Antibodies, Viral; Child; Child, Preschool; Cross Protection; Dengue; Dengue Vaccines; Female; Humans; Immunity, Humoral; Immunization Schedule; Malaysia; Male; Single-Blind Method; Vaccination

Topics: COVID-19; Dengue; Humans; Malaysia; Pandemics

This research aims to predict dengue fever cases in Malaysia using machine learning techniques. A dataset consisting of weekly dengue cases at the state level in Malaysia from 2010 to 2016 was obtained from the Malaysia Open Data website and includes variables such as climate, geography, and demographics. Six different long short-term memory (LSTM) models were developed and compared for dengue prediction in Malaysia: LSTM, stacked LSTM (S-LSTM), LSTM with temporal attention (TA-LSTM), S-LSTM with temporal attention (STA-LSTM), LSTM with spatial attention (SA-LSTM), and S-LSTM with spatial attention (SSA-LSTM). The models were trained and evaluated on a dataset of monthly dengue cases in Malaysia from 2010 to 2016, with the task of predicting the number of dengue cases based on various climate, topographic, demographic, and land-use variables. The SSA-LSTM model, which used both stacked LSTM layers and spatial attention, performed the best, with an average root mean squared error (RMSE) of 3.17 across all lookback periods. When compared to three benchmark models (SVM, DT, ANN), the SSA-LSTM model had a significantly lower average RMSE. The SSA-LSTM model also performed well in different states in Malaysia, with RMSE values ranging from 2.91 to 4.55. When comparing temporal and spatial attention models, the spatial models generally performed better at predicting dengue cases. The SSA-LSTM model was also found to perform well at different prediction horizons, with the lowest RMSE at 4- and 5-month lookback periods. Overall, the results suggest that the SSA-LSTM model is effective at predicting dengue cases in Malaysia.

Topics: Climate; Deep Learning; Dengue; Humans; Machine Learning; Malaysia

Fogging is a conventional technique used to combat Aedes mosquitoes and prevent dengue disease. It is often implemented in outbreak areas or areas harbouring a high density of Aedes mosquitoes. Currently, studies on stakeholders' attitudes towards fogging are still limited in number. Therefore, this study aims to assess Malaysian attitudes, and identify the predicting factors influencing such attitudes.. A validated instrument was used to interview 399 randomly selected respondents from the public (n = 202, 50.6%) and scientists (n = 197, 49.4%) in the Klang Valley region of Malaysia. The data were analysed using PLS-SEM involving Smart-PLS software.. The results confirmed that stakeholder attitudes toward fogging should be viewed in terms of a multi-dimensional association. The stakeholders surveyed were highly positive with regard to the application of fogging to control dengue but professed moderate concerns as to associated risks. The PLS-SEM analyses demonstrated that the perceived benefit was the most important factor influencing attitudes, followed by trust in key players.. This result provides a good insight from the perspective of education and unravels the underlying fundamentals of stakeholders' attitudes toward the fogging technique. The findings also provide a positive indicator to the responsible parties involved to continue the usage of this technique in conjunction with improvements with regard to its safety aspects, and possibly in combination with other environmental-friendly alternatives in order to achieve a healthy environment without dengue in Malaysia.

Topics: Aedes; Animals; Asian People; Attitude; Attitude to Health; Communicable Disease Control; Dengue; Fumigation; Humans; Malaysia; Random Allocation; Stakeholder Participation

Dengue is widespread globally, but it is more severe in hyperendemic regions where the virus, its vectors, and its human hosts naturally occur. The problem is particularly acute in cities, where outbreaks affect a large human population living in a wide array of socio-environmental conditions. Controlling outbreaks will rely largely on systematic data collection and analysis approaches to uncover nuances on a city-by-city basis due to the diversity of factors.. The main objective of this study is to consolidate and analyse the dengue case dataset amassed by the e-Dengue web-based information system, developed by the Ministry of Health Malaysia, to improve our epidemiological understanding.. We retrieved data from the e-Dengue system and integrated a total of 18,812 cases from 2012 to 2019 (8 years) with meteorological data, geoinformatics techniques, and socio-environmental observations to identify plausible factors that could have caused dengue outbreaks in Ipoh, a hyperendemic city in Malaysia.. The rainfall trend characterised by a linearity of R. Our work demonstrates the novelty of the e-Dengue system, which can identify outbreak factors at high resolution when integrated with non-medical fields. Besides dengue, the techniques and insights laid out in this paper are valuable, at large, for advancing control strategies for other mosquito-borne diseases such as malaria, chikungunya, and zika in other hyperendemic cities elsewhere globally.

Topics: Animals; Cities; Dengue; Disease Outbreaks; Humans; Information Systems; Malaysia; Zika Virus; Zika Virus Infection

Globally, the COVID-19 pandemic has affected the transmission dynamics and distribution of dengue. Therefore, this study aims to describe the impact of the COVID-19 pandemic on the geographic and demographic distribution of dengue incidence in Malaysia.. This study analyzed dengue cases from January 2014 to December 2021 and COVID-19 confirmed cases from January 2020 to December 2021 which was divided into the pre (2014 to 2019) and during COVID-19 pandemic (2020 to 2021) phases. The average annual dengue case incidence for geographical and demographic subgroups were calculated and compared between the pre and during the COVID-19 pandemic phases. In addition, Spearman rank correlation was performed to determine the correlation between weekly dengue and COVID-19 cases during the COVID-19 pandemic phase.. Dengue trends in Malaysia showed a 4-year cyclical trend with dengue case incidence peaking in 2015 and 2019 and subsequently decreasing in the following years. Reductions of 44.0% in average dengue cases during the COVID-19 pandemic compared to the pre-pandemic phase was observed at the national level. Higher dengue cases were reported among males, individuals aged 20-34 years, and Malaysians across both phases. Weekly dengue cases were significantly correlated (. There was a reduction in dengue incidence during the COVID-19 pandemic compared to the pre-pandemic phase. Significant reductions were observed across all demographic groups except for the older population (>75 years) across the two phases.

Topics: Asian People; COVID-19; Dengue; Female; Humans; Incidence; Malaysia; Male; Pandemics

Temephos is the World Health Organization (WHO) recommended larvicide and is still being utilized worldwide to control larvae of dengue vectors; Aedes aegypti and Aedes albopictus. The efficacy of a commercial temephos product; Temebate® to exterminate the local populations of Ae. albopictus larvae originated from different land use particularly dengue-risk and dengue-free housing localities as well as agrarian localities including oil palm plantations, rubber estates and paddy fields was assessed to verify its bioefficacy in these localities. Field populations of Ae. albopictus larvae were attained via a larval survey at each study locality. Each Ae. albopictus larval population was subjected to a 24-h larval bioassay using Temebate® at operational dosage of 1 mg/L. Almost all Ae. albopictus larval populations demonstrated mortalities between 7.00% and 100.00% by the end of the first 4 h of Temebate® exposure with the resistance ratios between 0.94 and 8.33. After 24 h of Temebate® exposure, all sixteen Ae. albopictus larval populations exhibited increased mortalities with ten of them showing 100% mortalities. These results confirmed the relevance of Temebate® to be continuously used by the residents of these localities as their control efforts against dengue vectors. Nevertheless, Temebate® application by consumers in dengue-risk localities need to be carefully monitored to prevent further development of temephos resistance among Ae. albopictus populations and substantiated with other vector control approaches.

Topics: Aedes; Animals; Dengue; Humans; Insecticide Resistance; Insecticides; Larva; Malaysia; Mosquito Vectors; Temefos

The aim of this study was to analyze the prevention and control practices against Zika virus (ZIKV) infection among pregnant women in Malaysia. A cross-sectional study was conducted among pregnant women who received antenatal care. Only 7.8% reported that they abstained from sex or used barrier methods during sexual intercourse to prevent ZIKV transmission. The odds of abstaining from sex or using barrier methods were significantly higher among the Chinese ethnic group than the Malay ethnic group (odds ratio [OR] = 4.569; 95% confidence interval [CI]: 2.696-7.743). A total ZIKV knowledge score of 12-24 was also significantly associated with higher odds of abstaining from sex or using barrier methods than a score of 0-11 (OR = 2.819; 95% CI: 1.682-4.725). In total, 38.6% of women had a higher mean total score for all the current mosquito control practices than they did before hearing of ZIKV. Participants living in bungalows or village houses (OR = 2.006; 95% CI: 1.023-3.936) and low-rise houses (OR = 1.566; 95% CI: 1.109-2.212) were more likely to have a higher mean total score of current mosquito control practices than the practices before hearing of ZIKV compared to those in high-rise houses. The lack of ZIKV knowledge and control practices provides insight for the pre-emptive and prompt development of health education systems for pregnant women during antenatal care visits.

Topics: Cross-Sectional Studies; Dengue; Female; Humans; Malaysia; Pregnancy; Pregnant Women; Zika Virus; Zika Virus Infection

Dengue remains hyperendemic in Malaysia despite extensive vector control activities. With dynamic changes in land use, urbanisation and population movement, periodic updates on dengue transmission patterns are crucial to ensure the implementation of effective control strategies. We sought to assess shifts in the trends and spatial patterns of dengue in Kelantan, a north-eastern state of Malaysia (5°15'N 102°0'E).. This study incorporated data from the national dengue monitoring system (eDengue system). Confirmed dengue cases registered in Kelantan with disease onset between January 1, 2016 and December 31, 2018 were included in the study. Yearly changes in dengue incidence were mapped by using ArcGIS. Hotspot analysis was performed using Getis-Ord Gi to track changes in the trends of dengue spatial clustering.. A total of 10 645 dengue cases were recorded in Kelantan between 2016 and 2018, with an average of 10 dengue cases reported daily (standard deviation, 11.02). Areas with persistently high dengue incidence were seen mainly in the coastal region for the 3-year period. However, the hotspots shifted over time with a gradual dispersion of hotspots to their adjacent districts.. A notable shift in the spatial patterns of dengue was observed. We were able to glimpse the shift of dengue from an urban to peri-urban disease with the possible effect of a state-wide population movement that affects dengue transmission.

Topics: Dengue; Humans; Incidence; Malaysia; Spatial Analysis; Urbanization

The aim of this study is to assess knowledge and attitudes toward Zika virus disease (ZVD) as well as mosquito prevention practices in Malaysia at a nationwide level.. Computer-assisted telephone interviews (CATI) were conducted between June 2019 and February 2020.. There are gaps in knowledge about the symptoms, mode of transmission, and risk of microcephaly. The mean for the Zika-related knowledge score was 5.9 (SD ± 4.4) out of a possible score of 14. The majority perceived. Zika prevention measures should be targeted in priority toward residents in lower socioeconomic neighborhoods. Campaigns should focus on messages highlighting the high risk of getting dengue.

Topics: Dengue; Health Knowledge, Attitudes, Practice; Humans; Malaysia; Zika Virus; Zika Virus Infection

Dengue is a major mosquito-borne disease in many tropical and sub-tropical countries worldwide, with entomological surveillance and control activities as the key management approaches. This study aimed to explore the spatial dispersal of the vector Aedes albopictus, captured by the modified sticky ovitrap (MSO) in residential areas with low-rise buildings in Selangor, Malaysia. Distribution maps were created and shown as temporally distinguished classes based on hotspot analysis by Getis-Ord; spatial autocorrelation assessed by semivariograms using the exponential Kernel function; and universal Kriging showing areas with estimated high and low vector densities. Distribution, hotspot and interpolated maps were analysed based on the total number of mosquitoes by month and week. All maps in the present study were generated and visualised in ArcMap. Spatial autocorrelation of Ae. albopictus based on the monthly occurrence of Ae. albopictus was found in March, April, October, November and December 2018, and when based on the weekly numbers, in weeks 1, 2, 3, 5, 7, 12, 14, 25, 26, 27, 31, 33, 42, 49 and 52. Semivariograms, based on the monthly and weekly numbers of Ae. albopictus, indicated spatial autocorrelation of the species extending between 50 and 70 m. The mosquito density maps reported in this study may provide beneficial information to facilitate implementation of more efficient entomological control activities.

Topics: Aedes; Animals; Dengue; Disease Vectors; Malaysia; Mosquito Vectors; Spatial Analysis

Dengue is a vector-borne disease affected by meteorological factors and is commonly recorded from ground stations. Data from ground station have limited spatial representation and accuracy, which can be overcome using satellite-based Earth Observation (EO) recordings instead. EO-based meteorological recordings can help to provide a better understanding of the correlations between meteorological variables and dengue cases. This paper aimed to first validate the satellite-based (EO) data of temperature, wind speed, and rainfall using ground station data. Subsequently, we aimed to determine if the spatially matched EO data correlated with dengue fever cases from 2011 to 2019 in Malaysia. EO data were spatially matched with the data from four ground stations located at states and districts in the central (Selangor, Petaling) and east coast (Kelantan, Kota Baharu) geographical regions of Peninsular Malaysia. Spearman's rank-order correlation coefficient (ρ) was performed to examine the correlation between EO and ground station data. A cross-correlation analysis with an eight-week lag period was performed to examine the magnitude of correlation between EO data and dengue case across the three time periods (2011-2019, 2015-2019, 2011-2014). The highest correlation between the ground-based stations and corresponding EO data were reported for temperature (mean ρ = 0.779), followed by rainfall (mean ρ = 0.687) and wind speed (mean ρ = 0.639). Overall, positive correlations were observed between weekly dengue cases and rainfall for Selangor and Petaling across all time periods with significant correlations being observed for the period from 2011 to 2019 and 2015 to 2019. In addition, positive significant correlations were also observed between weekly dengue cases and temperature for Kelantan and Kota Baharu across all time periods, while negative significant correlations between weekly dengue cases and temperature were observed in Selangor and Petaling across all time periods. Overall negative correlations were observed between weekly dengue cases and wind speed in all areas from 2011 to 2019 and 2015 to 2019, with significant correlations being observed for the period from 2015 to 2019. EO-derived meteorological variables explained 48.2% of the variation in dengue cases in Selangor. Moderate to strong correlations were observed between meteorological variables recorded from EO data derived from satellites and ground stations, thereby justifying the use of EO data a

Topics: Dengue; Humans; Incidence; Malaysia; Meteorological Concepts; Temperature; Wind

Dengue fever is a mosquito-borne viral infection of humans caused by a virus of the Flaviviridae family. In Malaysia the annual incidence risk of dengue fever for the period 2000 to 2019 ranged from 30 to 390 cases per 100,000. The aim of this paper was to identify spatial, temporal and spatio-temporal clusters of dengue fever in Peninsular Malaysia for the period 2015 to 2017. Counts of confirmed incident cases of dengue fever for each of the 86 districts of Peninsular Malaysia for the period 1 January 2015 to 31 December 2017 (inclusive) and district-level census data allowed us to calculate the incidence rate of dengue fever, defined as the number of confirmed cases of dengue fever per 100,000 person-years at risk. We applied Kulldorff's cylindrical space-time scan statistic and Takahashi et al.'s prismatic space-time scan statistic to the data. We identified no major differences in the number and location of spatial clusters of dengue incidence for 2015, 2016 and 2017 using Kulldorff's and Takahashi et al.'s method. Spatio-temporal clusters of dengue occurred at several times throughout each year in various high population dense areas. These clusters not only included high population density districts but also their adjacent district neighbours. The temporal clustering of dengue cases during the monsoon season (mid September to late December each year) implies that there is a biologically plausible causal association between rainfall and the incidence of dengue. Identification of locations and time periods when the frequency of dengue is high allows Malaysian public health authorities to be more objective in their decision making around vector control and dengue public awareness campaigns. Future research will quantify the association between population density and rainfall on dengue incidence. This will allow health authorities to take a more proactive approach for dengue control.

Topics: Animals; Cluster Analysis; Dengue; Humans; Incidence; Malaysia; Spatio-Temporal Analysis

Dengue virus (DENV) infection is a major public health concern, posing huge economic and disease burdens globally. In Malaysia, the incidence of DENV infections has increased significantly over the years. Nevertheless, the passive surveillance mechanism applied may not capture the actual magnitude of DENV infection. There was also a paucity of community-based studies exploring DENV seroprevalence. This study aimed to determine the DENV seroprevalence and the associated factors among the urban population in Petaling district, Malaysia. A population-based cross-sectional study was conducted from 18 August to 26 October 2018 with 533 participants recruited. Blood samples were collected and analysed for DENV seropositivity using a composite reference standard comprised of three dengue serological tests. Associated factors were identified by fitting Generalised Linear Mixed Models with binomial error structure and logit link function. DENV seroprevalence obtained was 79.0% (95% CI: 75.2-82.4%). The age-specific DENV seroprevalence showed an increasing trend with advancing age, from 22.7% (95% CI: 9.6-45.0%) for those aged below five years old to 94.9% (95% CI: 81.3-98.7%) for those aged ≥60 years old. Only age group and house level were found to be significant factors associated with DENV seropositivity. The odds of being DENV seropositive generally increased with age, from 13.43 (95% CI: 2.77-65.22) for the 5-9 years old age group to 384.77 (95% CI: 39.27-3769.97) for the ≥60 years old age group, as compared to those aged below 5 years old. For house level, those who lived on the first and second floor (OR: 8.98, 95% CI: 3.16-25.12) and the third floor and above (OR: 4.82, 95% CI: 1.89-12.32) had greater odds of being DENV seropositive compared to those living on the ground floor. This study demonstrated the persistently high DENV seroprevalence among the urban population in Petaling district, which could be useful to evaluate dengue control measures taken and estimate more accurate disease incidence. The associated factors with DENV seropositivity identified could also contribute to undertaking more targeted preventive and control measures.

Topics: Antibodies, Viral; Child; Child, Preschool; Cross-Sectional Studies; Dengue; Dengue Virus; Humans; Malaysia; Middle Aged; Seroepidemiologic Studies

In recent years, the number of leptospirosis cases, including the number of deaths, has exponentially increased in Malaysia. From June 2016 to February 2018, blood samples of 321 febrile patients with the presumptive diagnosis of dengue-like illness were examined for possible exposure to Leptospira. Two hundred fifty-five blood samples were tested as negative for dengue. Seminested polymerase chain reaction (PCR) and IgM ELISA for leptospirosis were performed. From the samples, an overall prevalence for leptospirosis based on PCR of 4.7% (12/255) was obtained. Eighteen percent (46/255) were positive for anti-Leptospira IgM antibodies. The genome sequences of six of 12 Leptospira PCR-positive samples showed > 97.0% similarity to Leptospira interrogans. One patient's sample consisted of Leptospira and chikungunya virus, suggesting a coinfection. Findings from the study suggest that leptospirosis is prevalent among dengue-negative febrile patients in Malaysia.

Topics: Antibodies, Bacterial; Dengue; Fever; Humans; Immunoglobulin M; Leptospira; Leptospirosis; Malaysia

Dengue remains a public health concern due to limited curative treatment and safe vaccine availability. Prevention by individual is utmost necessary but its practice is still lacking. Perceived risk to disease has been reported to exert a good effect on health behaviour change. However, limited evidence showed its relationship towards attitude and practice for dengue prevention. Hence, we aim to measure the mediating effect of dengue risk perception in the relationship between dengue attitude and dengue prevention practice. A cross-sectional study was conducted from April 2021 to November 2021 in a district of Seremban using a pre-validated questionnaire. Informed consent was obtained from the respondents prior to inclusion in the study. The study was approved by the ethical research committee. A total of 347 respondents took part in the survey, but only 341 data points were included in the final analysis. The majority of the respondents were female (63.0%), of Malay ethnicity (86.8%), married (55.4%), and currently employed (71.0%). The pooled confirmatory factor analysis result demonstrated an RMSEA value of 0.038 (<0.08), CFI value of 0.969 (>0.90), TLI value of 0.9565 (>0.90), and

Topics: Cross-Sectional Studies; Dengue; Female; Health Knowledge, Attitudes, Practice; Humans; Malaysia; Male; Surveys and Questionnaires

The release of over 6,000 genetically modified mosquitoes (GMM) into uninhabited Malaysian forests in 2010 was a frantic step on the part of the Malaysian government to combat the spread of dengue fever. The field trial was designed to control and reduce the dengue vector by producing offspring that die in the early developmental stage, thus decreasing the local Aedes aegypti population below the dengue transmission threshold. However, the GMM trials were discontinued in Malaysia despite being technologically feasible. The lack of systematic studies in terms of cost-benefit analysis, questionable research efficacy and safety-related concerns might have contributed to the termination of the field trial. Hence, this research aims to evaluate the feasibility of GMM release in Malaysia by using a holistic approach based on an Islamic ethical-legal assessment under the maslahah-mafsadah (benefit-risk) concept. Three main strategies based on the maslahah-mafsadah concept approach have been applied: 1) an evidence-based approach, 2) an impact-based approach and, 3) a priority approach. The analysis concluded that GMM could be categorised as zanniyyah (probable). GMM is a promising alternative for dengue control, but many issues must be addressed before its widespread adoption.

Topics: Aedes; Animals; Dengue; Humans; Islam; Malaysia; Mosquito Vectors

Several studies have reported a significant association of knowledge, attitude and preventive practice (KAP) regarding dengue infection among community's resident in endemic areas. In this study we aimed to assess and develop a reliable and valid KAP survey on the subject of dengue that is suitable for the resident population of Sabah, Malaysia.. A community-based cross-sectional study was conducted from October 2019 to February 2020 involving 468 respondents. Information on the socio-demographic characteristics of the participants (six items), their KAP (44, 15 and 18 items on knowledge, attitude and practice, respectively) and treatment-seeking behaviour (five items) towards dengue was collected using a structured questionnaire. Data analysis was performed using SPSS and R software in the R Studio environment. The knowledge section was analysed by two-parameter logistic item response theory (2-PL IRT) using ltm package. The construct validity and reliability of items for sections on attitude, practice and treatment-seeking behaviour were analysed using psy package.. For the knowledge section, only 70.5% (31/44) of items were within or close to the parameter acceptable range of -3 to + 3 of difficulty. In terms of discrimination, 65.9% (29/44) of items were within or close to the acceptable range of 0.35 to 2.5, and 24 items (54.5%) failed to fit the 2-PL IRT model (P < 0.05) after assessing by goodness-of-fit analysis. Only eight items were reliable and retained in the attitude section with a Kaiser-Meyer-Olkin (KMO) test value of > 0.7, while based on the communalities, 11 items in the attitude section were excluded due to very low h2, factor loading values and low correlation with the total (< 0.5). The practice section was found suitable for factor analysis because the KMO value was > 0.7. The communalities of the practice section showed that seven items had low h2 values (< 0.3), which were therefore excluded from further analysis, and only 11 items were retained.. The KAP items retained in the final version of the survey were reliable and valid to be use as a questionnaire reference when conducting future similar studies among the population of Sabah.

Topics: Cross-Sectional Studies; Dengue; Factor Analysis, Statistical; Health Knowledge, Attitudes, Practice; Humans; Malaysia; Reproducibility of Results; Surveys and Questionnaires

This study explored the contribution of viral respiratory infections (VRIs) in dengue-like illness (DLI) patients and their distinguishing clinicolaboratory parameters. Two hundred DLI patients were prospectively recruited (July 1- October 1, 2019) from a community clinic in Southern Malaysia. Patients ≥ 18 years with acute fever and fulfilling the WHO criteria of probable dengue were recruited. They underwent blood testing: blood counts, rapid dengue tests (nonstructural antigen-1/IgM) and polymerase chain reaction (PCR) for dengue, Zika, chikungunya, and Leptospira. Nasopharyngeal swabs (NPSs) were collected for FilmArray®RP2plus testing. From the 200 NPSs, 58 respiratory viruses (RVs) were detected in 54 patients. Of the 96 dengue-confirmed cases, 86 had dengue mono-infection, and 10 were coinfected with RVs. Of the 104 nondengue, 44 were RV positive and 4 Leptospira positive. Zika and chikungunya virus were not detected. Overall, the etiological diagnosis was confirmed for 72% of patients. Clinicolaboratory parameters were compared between dengue mono-infection and VRI mono-infection. Patients with coinfections were excluded. Multiple logistic regression showed that recent household/neighborhood history of dengue (adjusted odds ratio [aOR]: 5.9, 95% CI = 1.7-20.7), leukopenia (aOR: 12.5, 95% CI = 2.6-61.4) and thrombocytopenia (aOR: 5.5, 95% CI = 1.3-23.0) predicted dengue. Inversely, rhinorrhoea (aOR: 0.1, 95% CI = 0.01-0.3) and cough (aOR: 0.3, 95% CI = 0.1-0.9) favored VRI. Thus, VRIs comprise many infections diagnosed initially as DLIs. Early clinicolaboratory parameters can guide physicians screen patients for further testing.

Topics: Adult; Dengue; Female; Humans; Malaysia; Male; Prospective Studies; Respiratory Tract Infections; Virus Diseases; Young Adult

Dengue is a complex disease with an increasing number of infections worldwide. This study aimed to analyse spatiotemporal dengue outbreaks using geospatial techniques and examine the effects of the weather on dengue outbreaks in the Klang Valley area, Kuala Lumpur, Malaysia. Daily weather variables including rainfall, temperature (maximum and minimum) and wind speed were acquired together with the daily reported dengue cases data from 2001 to 2011 and converted into geospatial format to identify whether there was a specific pattern of the dengue outbreaks. The association between these variables and dengue outbreaks was assessed using Spearman's correlation. The result showed that dengue outbreaks consistently occurred in the study area during a 11-year study period. And that the strongest outbreaks frequently occurred in two high-rise apartment buildings located in Kuala Lumpur City centre. The results also show significant negative correlations between maximum temperature and minimum temperature on dengue outbreaks around the study area as well as in the area of the high-rise apartment buildings in Kuala Lumpur City centre.

Topics: Cities; Dengue; Disease Outbreaks; Humans; Malaysia; Weather

Dengue, a vector-borne viral illness, shows worldwide widening spatial distribution beyond its point of origination, namely, the tropical belt. The persistent hyperendemicity in Malaysia has resulted in the formation of the dengue early warning system. However, weather variables are yet to be fully utilized for prevention and control activities, particularly in east-coast peninsular Malaysia where limited studies have been conducted. We aim to provide a time-based estimate of possible dengue incidence increase following weather-related changes, thereby highlighting potential dengue outbreaks.. All serologically confirmed dengue patients in Kelantan, a northeastern state in Malaysia, registered in the eDengue system with an onset of disease from January 2016 to December 2018, were included in the study with the exclusion of duplicate entry. Using a generalized additive model, climate data collected from the Kota Bharu weather station (latitude 6°10'N, longitude 102°18'E) was analysed with dengue data.. A cyclical pattern of dengue cases was observed with annual peaks coinciding with the intermonsoon period. Our analysis reveals that maximum temperature, mean temperature, rainfall, and wind speed have a significant nonlinear effect on dengue cases in Kelantan. Our model can explain approximately 8.2% of dengue incidence variabilities.. Weather variables affect nearly 10% of the dengue incidences in Northeast Malaysia, thereby making it a relevant variable to be included in a dengue early warning system. Interventions such as vector control activities targeting the intermonsoon period are recommended.

Topics: Animals; Climate; Climate Models; Culicidae; Dengue; Disease Outbreaks; Disease Vectors; Epidemiological Models; Forecasting; Humans; Incidence; Malaysia; Seasons; Temperature; Weather

The dengue virus type 3 (DENV-3) homotypic outbreak cycles reported in Klang Valley, Malaysia in 1992-1995 and 2002 demonstrated different epidemic magnitude and duration. These outbreak cycles were caused by two closely related strains of viruses within the DENV-3 genotype II (DENV-3/II). The role of viral genotypic diversity and factors that could have influenced this phenomenon were investigated. The serum neutralisation sensitivity of DEN3/II strains responsible for the DENV-3 outbreak cycles in 1992-1995 and 2002 were examined. Representative virus isolates from the respective outbreaks were subjected to virus neutralisation assay using identified sera of patients with homotypic (DENV-3) or heterotypic dengue infections (DENV-1 and DENV-2). Results from the study suggested that isolates representing DENV-3/II group E (DENV-3/II-E) from the 1992-1995 outbreak and DENV-3/II group F (DENV-3/II-F) from the 2002 outbreak were neutralised at similar capacity (intergenotypic differences <2-fold) by sera of patients infected with DENV-3, DENV-1 and DENV-2/Asian genotypes. Sera of the DENV-2/Cosmopolitan infection efficiently neutralised DENV-3/II-F (FRNT50 = 508.0) at a similar neutralisation capacity against its own homotypic serotype, DENV-2 (FRNT50 = 452.5), but not against DENV-3/II-E (FRNT50 = 100.8). The different neutralisation sensitivities of DENV-3/II strains towards the cross-reacting DENV-2 heterotypic immunity could play a role in shaping the DENV-3 recurring outbreaks pattern in Malaysia. Two genetic variations, E-132 (H/Y) and E-479 (A/V) were identified on the envelope protein of DENV-3/II-E and DENV-3/II-F, respectively. The E-132 variation was predicted to affect the protein stability. A more extensive study, however, on the implication of the naturally occurring genetic variations within closely related DENV genotypes on the neutralisation profile and protective immunity would be needed for a better understanding of the DENV spread pattern in a hyperendemic setting.

Topics: Antibodies, Neutralizing; Antibodies, Viral; Dengue; Dengue Virus; Disease Outbreaks; Gene Products, env; Genotype; Humans; Malaysia

Topics: Aedes; Animals; Dengue; Dengue Virus; Malaysia; Mosquito Vectors; Pest Control, Biological; Virus Replication; Wolbachia

Early diagnosis of dengue is important to ensure proper management of patients and effective implementation of control measures. The present study was undertaken to determine the outcome of the implementation of dengue NS1-antigen (Ag) rapid diagnostic test (RDT) in the confirmation of dengue at the first patient hospital visit at the University Malaya Medical Centre. A total of 1036 and 1097 sera from the year 2008 and 2015 were used, representing samples from before and after dengue NS1-Ag RDT was implemented as routine diagnostic at the hospital. Results showed that similar dengue confirmation percentage (56%) was made in 2008 and 2015, regardless of the main laboratory diagnostic method used. Confirmation of dengue, however, increased to 68% and 73% when dengue NS1-Ag test or dengue immunoglobulin M-capture enzyme-linked immunosorbent assay was used as the second test for the 2008 and 2015 samples, respectively. Detection of dengue virus (DENV) using multiplex reverse transcription-polymerase chain reaction (RT-PCR) showed that DENV-1 was the highest in circulation in 2008 and that both DENV-1 and DENV-2 were dominant in 2015. In summary, the present study demonstrated that the introduction and use of the dengue NS1-Ag RDT did not change or compromise confirmation of dengue, highlighting the advantage of using the method. With the reducing cost of molecular detection tools, DENV detection using RT-PCR remains a viable option for further confirmation of dengue in hospital settings.

Topics: Antibodies, Viral; Antigens, Viral; Clinical Laboratory Techniques; Dengue; Dengue Virus; Early Diagnosis; Enzyme-Linked Immunosorbent Assay; Humans; Immunoglobulin M; Malaysia; Reagent Kits, Diagnostic; Sensitivity and Specificity; Serogroup; Viral Nonstructural Proteins

Dengue fever is a mosquito-borne disease that affects nearly 3.9 billion people globally. Dengue remains endemic in Malaysia since its outbreak in the 1980's, with its highest concentration of cases in the state of Selangor. Predictors of dengue fever outbreaks could provide timely information for health officials to implement preventative actions. In this study, five districts in Selangor, Malaysia, that demonstrated the highest incidence of dengue fever from 2013 to 2017 were evaluated for the best machine learning model to predict Dengue outbreaks. Climate variables such as temperature, wind speed, humidity and rainfall were used in each model. Based on results, the SVM (linear kernel) exhibited the best prediction performance (Accuracy = 70%, Sensitivity = 14%, Specificity = 95%, Precision = 56%). However, the sensitivity for SVM (linear) for the testing sample increased up to 63.54% compared to 14.4% for imbalanced data (original data). The week-of-the-year was the most important predictor in the SVM model. This study exemplifies that machine learning has respectable potential for the prediction of dengue outbreaks. Future research should consider boosting, or using, nature inspired algorithms to develop a dengue prediction model.

Topics: Aedes; Algorithms; Animals; Climate; Dengue; Disease Outbreaks; Forecasting; Humans; Incidence; Machine Learning; Malaysia; Mosquito Vectors; Seasons; Temperature; Vector Borne Diseases

Dengue incidence has grown dramatically around the world in recent years. Vector control is the only method to reduce dengue incidence due to the lack of a vaccine available. By understanding the factors contributed to the vector densities such as environmental and sociological factors, dengue prevention and control may succeed.. This study is aimed at determining the impact of sociological and environmental factors contributing to dengue cases.. The study surveyed 379 respondents with dengue history. The socio-environmental factors were evaluated by chi-square and binary regression.. The chi-square results revealed sociological factors associated between family with dengue experience such as older age (p =0.012), fewer than four people in the household (p= 0.008), working people (p= 0.004) and apartment/terrace houses (p=0.023). Similarly, there is a significant association between respondent's dengue history and houses that are shaded with vegetation (p= 0.012) and the present of public playground areas near the residential (p = 0.011).. The study identified socio-environmental factors that play an important role in the abundance of Aedes mosquitoes and also for the local dengue control measures.

Topics: Adolescent; Adult; Aedes; Aged; Animals; Dengue; Female; Humans; Malaysia; Male; Middle Aged; Mosquito Vectors; Young Adult

Dengue, an acute infectious disease caused by a flavivirus, is a threat to global health. There is sparse evidence exploring obesity and the development of more severe dengue cases in adults. With increasing prevalence of obesity in areas with a high risk of dengue infection, obesity may increase the burden and mortality related to dengue infection. Our study aimed to determine the association between obesity and the development of more severe dengue infection in primary healthcare settings and whether these associations were modified by dengue fever phase.. A cohort study was conducted among laboratory-confirmed dengue patients aged >18 y in the central region of Peninsular Malaysia from May 2016 to November 2017. We collected demographic, clinical history, physical examination and laboratory examination information using a standardized form. Dengue severity (DS) was defined as either dengue with warning signs or severe dengue. Participants underwent daily follow-up, during which we recorded their vital signs, warning signs and full blood count results. Incidence of DS was modeled using mixed-effects logistic regression. Changes in platelet count and hematocrit were modeled using mixed-effects linear regression. The final multivariable models were adjusted for age, gender, ethnicity and previous dengue infection.. A total of 173 patients were enrolled and followed up. The mean body mass index (BMI) was 37.4±13.75 kg/m2. The majority of patients were Malay (65.9%), followed by Chinese (17.3%), Indian (12.7%) and other ethnic groups (4.1%). A total of 90 patients (52.0%) were male while 36 patients (20.8%) had a previous history of dengue infection. BMI was significantly associated with DS (adjusted OR=1.17; 95% CI 1.04 to 1.34) and hematocrit (%) (aβ=0.09; 95% CI 0.01 to 0.16), but not with platelet count (x103/µL) (aβ=-0.01; 95% CI -0.84 to 0.81). In the dose response analysis, we found that as BMI increases, the odds of DS, hematocrit levels and platelet levels increase during the first phase of dengue fever.. Higher BMI and higher hematocrit levels were associated with higher odds of DS. Among those with high BMI, the development of DS was observed during phase one of dengue fever instead of during phase two. These novel results could be used by clinicians to help them risk-stratify dengue patients for closer monitoring and subsequent prevention of severe dengue complications.

Topics: Adult; Body Mass Index; Cohort Studies; Dengue; Humans; Malaysia; Male; Platelet Count; Severe Dengue

In recent decades, dengue outbreaks have become increasingly common around the developing countries, including Malaysia. Thus, it is essential for rural as well as urbanised livelihood to understand the distribution pattern of this infection. The objective of this study is to determine the trend of dengue cases reported from the year 2014 to 2018 and the spatial pattern for this spread. Spatial statistical analyses conducted found that the distribution pattern and spatial mean centre for dengue cases were clustered in the eastern part of the Bangi region. Directional distribution observed that the elongated polygon of dengue cluster stretched from the Northeast to the Southwest of Bangi District. The standard distance observed for dengue cases was smallest in the year 2014 (0.017 m), and largest in 2016 (0.019 m), whereas in the year 2015, 2017 and 2018, it measured 0.018 m. The average nearest neighbour analysis also displayed clustered patterns for dengue cases in the Bangi District. The three spatial statistical analyses (spatial mean centre, standard distance and directional distribution) findings illustrate that the dengue cases from the year 2014 to 2018 are clustered in the Northeast to the Southwest of the study region.

Topics: Cluster Analysis; Dengue; Disease Outbreaks; Humans; Malaysia; Spatial Analysis

The state of Selangor, in Malaysia consist of urban and peri-urban centres with good transportation system, and suitable temperature levels with high precipitations and humidity which make the state ideal for high number of dengue cases, annually. This study investigates if districts within the Selangor state do influence each other in determining pattern of dengue cases. Study compares two different models; the Autoregressive Integrated Moving Average (ARIMA) and Ensemble ARIMA models, using the Akaike Information Criterion (AIC) and Bayesian Information Criterion (BIC) measurement to gauge their performance tools. ARIMA model is developed using the epidemiological data of dengue cases, whereas ensemble ARIMA incorporates the neighbouring regions' dengue models as the exogenous variable (X), into traditional ARIMA model. Ensemble ARIMA models have better model fit compared to the basic ARIMA models by incorporating neighbuoring effects of seven districts which made of state of Selangor. The AIC and BIC values of ensemble ARIMA models to be smaller compared to traditional ARIMA counterpart models. Thus, study concludes that pattern of dengue cases for a district is subject to spatial effects of its neighbouring districts and number of dengue cases in the surrounding areas.

Topics: Algorithms; Climate; Dengue; Geography; Humans; Malaysia; Models, Statistical

In Malaysia, dengue remains a top priority disease and usage of insecticides is the main method for dengue vector control. Limited baseline insecticide resistance data in dengue hotspots has prompted us to conduct this study. The present study reports the use of a map on the insecticide susceptibility status of Aedes aegypti and Aedes albopictus to provide a quick visualization and overview of the distribution of insecticide resistance.. The insecticide resistance status of Aedes populations collected from 24 dengue hotspot areas from the period of December 2018 until June 2019 was proactively monitored using the World Health Organization standard protocol for adult and larval susceptibility testing was conducted, together with elucidation of the mechanisms involved in observed resistance. For resistance monitoring, susceptibility to three adulticides (permethrin, deltamethrin, and malathion) was tested, as well as susceptibility to the larvicide, temephos. Data showed significant resistance to both deltamethrin and permethrin (pyrethroid insecticides), and to malathion (organophosphate insecticide) in all sampled Aedes aegypti populations, while variable resistance patterns were found in the sampled Aedes albopictus populations. Temephos resistance was observed when larvae were tested using the diagnostic dosage of 0.012mg/L but not at the operational dosage of 1mg/L for both species.. The present study highlights evidence of a potential threat to the effectiveness of insecticides currently used in dengue vector control, and the urgent requirement for insecticide resistance management to be integrated into the National Dengue Control Program.

Topics: Aedes; Animals; Dengue; Female; Insecticide Resistance; Insecticides; Larva; Malaysia; Mosquito Vectors

Topics: Chikungunya Fever; Dengue; Humans; Malaysia; Zika Virus; Zika Virus Infection

Dengue is a major threat to public health globally. While point-of-care diagnosis of acute/recent dengue is available to reduce its mortality, a lack of rapid and accurate testing for the detection of previous dengue remains a hurdle in expanding dengue seroepidemiological surveys to inform its prevention, especially vaccination, to reduce dengue morbidity. This study evaluated ViroTrack Dengue Serostate, a biosensors-based semi-quantitative anti-dengue IgG (immunoglobulin G) immuno-magnetic agglutination assay for the diagnosis of previous and recent dengue in a single test. Blood samples were obtained from 484 healthy participants recruited randomly from two communities in Petaling district, Selangor, Malaysia. The reference tests were Panbio Dengue IgG indirect and capture enzyme-linked immunosorbent assays, in-house hemagglutination inhibition assay, and focus reduction neutralization test. Dengue Serostate had a sensitivity and specificity of 91.1% (95%CI 87.8-93.8) and 91.1% (95%CI 83.8-95.8) for the diagnosis of previous dengue, and 90.2% (95%CI 76.9-97.3) and 93.2% (95%CI 90.5-95.4) for the diagnosis of recent dengue, respectively. Its positive predictive value of 97.5% (95%CI 95.3-98.8) would prevent most dengue-naïve individuals from being vaccinated. ViroTrack Dengue Serostate's good point-of-care diagnostic accuracy can ease the conduct of dengue serosurveys to inform dengue vaccination strategy and facilitate pre-vaccination screening to ensure safety.

Topics: Adult; Antibodies, Viral; Biosensing Techniques; Dengue; Diagnostic Tests, Routine; Enzyme-Linked Immunosorbent Assay; Female; Humans; Immunoglobulin G; Malaysia; Point-of-Care Systems; Point-of-Care Testing; Sensitivity and Specificity; Young Adult

The challenges faced by healthcare personnel in relation to dengue prevention and control are perennial but noticeably unexplored. It is often difficult to translate policies and decision making by the elite into astute management in consonance with the needs of rank-and-file personnel. In this study, we assess the impact of governance on dengue prevention and control activities in Malaysia as narrated by the elite.. A qualitative study using a case-study approach was conducted between January 2019 and November 2019 in the districts of Gombak and Klang, where the relevant key informants were located. Nineteen interviews were conducted among elite healthcare personnel from different divisions: management, vector, laboratory, inspectorate, health promotion and entomology. Semi-structured interviews were conducted. The sample size was determined through saturation point criteria. Purposive sampling techniques were used to recruit the participants. The interviews were audio recorded, and the transcribed text was analysed with deductive thematic analysis.. Data analysis led to the development of 5 themes and 13 categories. The major principles of governance were embodied in a milieu of predicament, linked to constraints but also opportunities. The constraints resulted from inherent determinants of dengue outbreaks, the serviceability of governing policies and the macro-economics of budget allocation. The opportunities to sustain governance at the local operating level stem from a prevalent supportive internal management system, collaborative efforts among corresponding external government agencies and willingness to innovate and embrace novel technology.. Elites are influential, often well-informed personnel tasked with making decisions that can reverberate across an organisation, impacting future plans and strategic policies. Political arrangements at higher levels will reflect in advance the tone of how governance in dengue prevention and control is operationalised by entities and individuals at lower levels of the health system. The prevailing centralised structure in the Malaysian health system will continue to entrench the position of the elite and intertwine it with governance and its predicaments.

Topics: Dengue; Government Programs; Health Personnel; Humans; Malaysia; Qualitative Research

Dengue fever is the most common mosquito-borne infection worldwide where an expanding surveillance and characterization of this infection are needed to better inform the healthcare system. In this surveillance-based study, we explored the prevalence and distinguishing features of dengue fever amongst febrile patients in a large community-based health facility in southern peninsular Malaysia.. Over six months in 2018, we recruited 368 adults who met the WHO 2009 criteria for probable dengue infection. They underwent the following blood tests: full blood count, dengue virus (DENV) rapid diagnostic test (RDT), ELISA (dengue IgM and IgG), nested RT-PCR for dengue, multiplex qRT-PCR for Zika, Chikungunya and dengue as well as PCR tests for Leptopspira spp., Japanese encephalitis and West Nile virus.. Laboratory-confirmed dengue infections (defined by positive tests in NS1, IgM, high-titre IgG or nested RT-PCR) were found in 167 (45.4%) patients. Of these 167 dengue patients, only 104 (62.3%) were positive on rapid diagnostic testing. Dengue infection was significantly associated with the following features: family or neighbours with dengue in the past week (AOR: 3.59, 95% CI:2.14-6.00, p<0.001), cutaneous rash (AOR: 3.58, 95% CI:1.77-7.23, p<0.001), increased temperature (AOR: 1.33, 95% CI:1.04-1.70, p = 0.021), leucopenia (white cell count < 4,000/μL) (AOR: 3.44, 95% CI:1.72-6.89, p<0.001) and thrombocytopenia (platelet count <150,000/μL)(AOR: 4.63, 95% CI:2.33-9.21, p<0.001). Dengue infection was negatively associated with runny nose (AOR: 0.47, 95% CI:0.29-0.78, p = 0.003) and arthralgia (AOR: 0.42, 95% CI:0.24-0.75, p = 0.004). Serotyping by nested RT-PCR revealed mostly mono-infections with DENV-2 (n = 64), DENV-1 (n = 32) and DENV-3 (n = 17); 14 co-infections occurred with DENV-1/DENV-2 (n = 13) and DENV-1/DENV-4 (n = 1). Besides dengue, none of the pathogens above were found in patients' serum.. Acute undifferentiated febrile infections are a diagnostic challenge for community-based clinicians. Rapid diagnostic tests are increasingly used to diagnose dengue infection but negative tests should be interpreted with caution as they fail to detect a considerable proportion of dengue infection. Certain clinical features and haematological parameters are important in the clinical diagnosis of dengue infection.

Topics: Adult; Aged; Antibodies, Viral; Antigens, Viral; Blood Cell Count; Cross-Sectional Studies; Dengue; Dengue Virus; Enzyme-Linked Immunosorbent Assay; Female; Fever; Humans; Immunoglobulin G; Immunoglobulin M; Malaysia; Male; Middle Aged; Polymerase Chain Reaction

Outdoor Residual Spraying (ORS) technique is a complementary preventive measure for dengue. The alarming number of dengue cases in Malaysia requires an alternative method to control dengue besides the traditional method such as fogging. However, the introduction of new technologies depends on social acceptance. Therefore, this study was important to determine the factors that influence stakeholders' attitudes towards the ORS and the moderating factor. A validated instrument was used to randomly interview 399 respondents representing two stakeholder groups which consist of scientists, and the public in Klang Valley, Malaysia. The findings revealed that the stakeholders claimed to have a high degree of religiosity, a high level of trust in the key players, perceived ORS as having high benefits, and displayed highly positive attitudes towards the ORS. The attitudes model towards the ORS model was developed using the SmartPLS software version. The perceived benefit was endorsed as the most important direct predictor of attitudes towards the ORS (ß = 0.618, P<0.001), followed by trust in the key players (ß = 0.151, P<0.001). It is also interesting to note that religiosity served as a moderator for the association between perceived benefit (ß = 0.075, P = 0.024) and perceived risk (ß = 0.114, P = 0.006) with attitudes towards the ORS. The identified predictor factors of stakeholders' attitudes toward the ORS and the moderating factor can serve as indicators for social acceptance of ORS in developing countries. These indicators can help the policymakers in decision making to implement this technique.

Topics: Aedes; Animals; Attitude to Health; Dengue; Humans; Insecticides; Malaysia; Mosquito Control; Public Opinion; Stakeholder Participation; Surveys and Questionnaires; Trust

In China, Guangdong and Yunnan are the two most dengue-affected provinces. This study aimed to compare the epidemiological characteristics of dengue fever in Guangdong and Yunnan during 2004-2018.. Descriptive analyses were used to explore the temporal, spatial, and demographic distribution of dengue fever.. Of the 73,761 dengue cases reported in mainland China during 2004-2018, 93.7% indigenous and 65.9% imported cases occurred in Guangdong and Yunnan, respectively. A total of 55,970 and 5938 indigenous cases occurred in 108 Guangdong and 8 Yunnan counties, respectively during 2004-2018. Whereas 1146 and 3050 imported cases occurred in 84 Guangdong and 72 Yunnan counties, respectively during 2004-2018. Guangdong had a much higher average yearly indigenous incidence rate (3.65 (1/100000) vs 0.86 (1/100000)), but a much lower average yearly imported incidence rate (0.07 (1/100000) vs 0.44(1/100000)) compared with Yunnan in 2004-2018. Furthermore, dengue fever occurred more widely in space and more frequently in time in Guangdong. Guangdong and Yunnan had similar seasonal characteristics for dengue fever, but Guangdong had a longer peak period. Most dengue cases were clustered in the south-western border of Yunnan and the Pearl River Delta region in Guangdong. Most of the imported cases (93.9%) in Guangdong and Yunnan were from 9 Southeast Asian countries. Thailand, Cambodia, and Malaysia imported mainly into Guangdong while Myanmar and Laos imported into Yunnan. There was a strong male predominance among imported cases and an almost equal gender distribution among indigenous cases. Most dengue cases occurred in individuals aged 21-50 years, accounting for 57.3% (Guangdong) vs. 62.8% (Yunnan) of indigenous and 83.2% (Guangdong) vs. 62.6% (Yunnan) of imported cases. The associated major occupations (house worker or unemployed, retiree, and businessman, for indigenous cases; and businessman, for imported cases), were similar. However, farmers accounted for a larger proportion of dengue cases in Yunnan.. Identifying the different epidemiological characteristics of dengue fever in Guangdong and Yunnan can be helpful to formulate targeted, strategic plans, and implement effective public health prevention measures in China.

Topics: Cambodia; China; Dengue; Female; Humans; Laos; Malaysia; Male; Myanmar; Thailand

Knowledge of the interrelationship of mosquito communities and land use changes is of paramount importance to understand the potential risk of mosquito disease transmission. This study examined the effects of land use types in urban, peri-urban and natural landscapes on mosquito community structure to test whether the urban landscape is implicated in increased prevalence of potentially harmful mosquitoes. Three land use types (park, farm, and forest nested in urban, peri-urban and natural landscapes, respectively) in Klang Valley, Malaysia, were surveyed for mosquito larval habitat, mosquito abundance and diversity. We found that the nature of human activities in land use types can increase artificial larval habitats, supporting container-breeding vector specialists such as Aedes albopictus, a dengue vector. In addition, we observed a pattern of lower mosquito richness but higher mosquito abundance, characterised by the high prevalence of Ae. albopictus in the urban landscape. This was also reflected in the mosquito community structure whereby urban and peri-urban landscapes were composed of mainly vector species compared to a more diverse mosquito composition in natural landscape. This study suggested that good environmental management practices in the tropical urban landscape are of key importance for effective mosquito-borne disease management.

Topics: Aedes; Animals; Dengue; Ecosystem; Forests; Human Activities; Humans; Malaysia; Mosquito Vectors

Dengue virus (DENV), Japanese encephalitis virus (JEV), and Zika virus (ZIKV) are mosquito-borne flavivirus of medical importance in tropical countries such as Malaysia. However, much remains unknown regarding their prevalence among the underserved indigenous people (Orang Asli) living in communities in the forest fringe areas of Peninsular Malaysia. Information on the prevalence of diseases is necessary to elevate the effectiveness of disease control and preventive measures. This study aimed to determine the seroprevalence of the three major flaviviruses among the Orang Asli and investigate the association between demographic factors and seropositivities. Sampling activities were conducted in the Orang Asli villages to obtain serum samples and demographic data from consenting volunteers. The presence of DENV, JEV, and ZIKV immunoglobulin G (IgG) antibodies in the sera were examined using commercial enzyme-linked immunosorbent assay kits. A focus reduction neutralization assay was performed to measure virus-specific neutralizing antibodies. A total of 872 serum samples were obtained from the Orang Asli volunteers. Serological assay results revealed that DENV IgG, JEV IgG, and ZIKV IgG seropositivities among the Orang Asli were at 4.9%, 48.4%, and 13.2%, respectively. Neutralizing antibodies (FRNT50 ≥ 1:40) against JEV and ZIKV were found in 86.7% and 100.0%, respectively, out of the samples tested. Positive serology to all three viruses corresponded significantly to the age of the volunteers with increasing seropositivity in older volunteers. Findings from the study suggest that Orang Asli are at significant risk of contracting JEV and ZIKV infections despite the lack of active transmission of the viruses in the country.

Topics: Adult; Antibodies, Neutralizing; Antibodies, Viral; Cross Reactions; Dengue; Dengue Virus; Encephalitis Virus, Japanese; Encephalitis, Japanese; Enzyme-Linked Immunosorbent Assay; Female; Flavivirus; Humans; Immunoglobulin G; Indigenous Peoples; Malaysia; Male; Seroepidemiologic Studies; Young Adult; Zika Virus; Zika Virus Infection

Vector-borne viral diseases pose an urgent public health challenge, particularly in the tropics. Field releases of mosquitoes carrying bacterial symbionts that reduce vector competence are ongoing in Kuala Lumpur, Malaysia. Early results show that wAlbB Wolbachia can persist in mosquitoes in urban settings and decrease dengue incidence in humans.

Topics: Aedes; Animals; Antiviral Agents; Dengue; Dengue Virus; Humans; Malaysia; Mosquito Vectors; Wolbachia

The public health burden of dengue is most likely under reported. Current dengue control measures only considered symptomatic dengue transmission. Hence, there is a paucity of information on the epidemiology of inapparent dengue. This study reports that many people have been unknowingly exposed to dengue infection. Almost 10% and 70% of individuals without any history of dengue infection and living in a dengue hotspot, in Selangor, Malaysia, were dengue IgM and IgG positive respectively. When dengue-positive mosquitoes were detected in the hotspot, 11 (6.3%) of the 174 individuals tested were found to have dengue viremia, of which 10 were asymptomatic. Besides, upon detection of a dengue-infected mosquito, transmission was already widespread. In a clinical setting, it appears that people living with dengue patients have been exposed to dengue, whether asymptomatic or symptomatic. They can either have circulating viral RNA and/or presence of NS1 antigen. It is also possible that they are dengue seropositive. Collectively, the results indicate that actions taken to control dengue transmission after the first report of dengue cases may be already too late. The current study also revealed challenges in diagnosing clinically inapparent dengue in hyperendemic settings. There is no one best method for diagnosing inapparent dengue. This study demonstrates empirical evidence of inapparent dengue in different settings. Early dengue surveillance in the mosquito population and active serological/virological surveillance in humans can go hand in hand. More studies are required to investigate the epidemiology, seroprevalence, diagnostics, and control of inapparent dengue. It is also crucial to educate the public, health staff and medical professionals on asymptomatic dengue and to propagate awareness, which is important for controlling transmission.

Topics: Adolescent; Adult; Aedes; Aged; Animals; Cross-Sectional Studies; Dengue; Dengue Virus; Female; Hospitals; Humans; Malaysia; Male; Middle Aged; Real-Time Polymerase Chain Reaction; RNA, Viral; Seroepidemiologic Studies; Viremia; Young Adult

Dengue is an emerging infectious disease that infects up to 390 million people yearly. The growing demand of dengue diagnostics especially in low-resource settings gave rise to many rapid diagnostic tests (RDT). This study evaluated the accuracy and utility of ViroTrack Dengue Acute - a new biosensors-based dengue NS1 RDT, SD Bioline Dengue Duo NS1/IgM/IgG combo - a commercially available RDT, and SD Dengue NS1 Ag enzyme-linked immunosorbent assay (ELISA), for the diagnosis of acute dengue infection.. This prospective cross-sectional study consecutively recruited 494 patients with suspected dengue from a health clinic in Malaysia. Both RDTs were performed onsite. The evaluated ELISA and reference tests were performed in a virology laboratory. The reference tests comprised of a reverse transcription-polymerase chain reaction and three ELISAs for the detection of dengue NS1 antigen, IgM and IgG antibodies, respectively. The diagnostic performance of evaluated tests was computed using STATA version 12.. The sensitivity and specificity of ViroTrack were 62.3% (95%CI 55.6-68.7) and 95.0% (95%CI 91.7-97.3), versus 66.5% (95%CI 60.0-72.6) and 95.4% (95%CI 92.1-97.6) for SD NS1 ELISA, and 52.4% (95%CI 45.7-59.1) and 97.7% (95%CI 95.1-99.2) for NS1 component of SD Bioline, respectively. The combination of the latter with its IgM and IgG components were able to increase test sensitivity to 82.4% (95%CI 76.8-87.1) with corresponding decrease in specificity to 87.4% (95%CI 82.8-91.2). Although a positive test on any of the NS1 assays would increase the probability of dengue to above 90% in a patient, a negative result would only reduce this probability to 23.0-29.3%. In contrast, this probability of false negative diagnosis would be further reduced to 14.7% (95%CI 11.4-18.6) if SD Bioline NS1/IgM/IgG combo was negative.. The performance of ViroTrack Dengue Acute was comparable to SD Dengue NS1 Ag ELISA. Addition of serology components to SD Bioline Dengue Duo significantly improved its sensitivity and reduced its false negative rate such that it missed the fewest dengue patients, making it a better point-of-care diagnostic tool. New RDT like ViroTrack Dengue Acute may be a potential alternative to existing RDT if its combination with serology components is proven better in future studies.

Topics: Adolescent; Adult; Aged; Child; Child, Preschool; Communicable Diseases, Emerging; Cross-Sectional Studies; Dengue; Dengue Virus; Diagnostic Tests, Routine; Enzyme-Linked Immunosorbent Assay; Female; Humans; Immunoglobulin G; Immunoglobulin M; Infant; Malaysia; Male; Middle Aged; Point-of-Care Systems; Probability; Prospective Studies; Sensitivity and Specificity; Serotyping; Young Adult

The massive flood in Malaysia's east coast in December 2014 has placed Kelantan in a possible dengue outbreak risk. At this point, community awareness is essential in preventing disease spread. However, no data on knowledge, attitude, and practice (KAP) of dengue in Kelantan have existed in relevance to flood disaster, although such information is necessary for the vector control programs. The purpose of this study is to assess the KAP regarding dengue among school children from flooded and unflooded areas and to evaluate the effectiveness of the dengue health education program in improving their KAP level. A school-based pre- and post-tests design was utilized in this study whereby a booklet on dengue was distributed during the interphase of the tests. The information collected was on the socio-demographic, KAP and the source of dengue information. We statistically compared the KAP between the two study sites and the pre- and post-test scores to evaluate the health education program. A total of 203 students participated in the survey, and 51.7% of them were flood victims. When comparing the baseline KAP, the respondents from the unflooded area had higher knowledge scores compared to those from the flooded area (P<0.05), while non-significant differences were observed in the attitude and practice between the two study areas (P>0.05). The health education program significantly improved knowledge and practice in the flooded area and knowledge only in the unflooded area (P<0.05). The multinomial regression analysis suggests that age and dengue history are the primary determinants that influence the high practice level in both areas. We suggest the need to increase routine dengue health education programs to all age groups targeting both high and low dengue risk areas, and the necessity to ensure the translation of positive knowledge and attitude changes into real dengue preventive practices.

Topics: Adolescent; Communicable Disease Control; Community-Acquired Infections; Cross-Sectional Studies; Dengue; Female; Health Education; Health Knowledge, Attitudes, Practice; Humans; Malaysia; Male; Schools; Students; Surveys and Questionnaires

Dengue diagnostics have come a long way. Attempts at breaking away from lab-oriented dengue detection, such as NS1 antigen, IgM or IgG antibodies detection have extensively received numerous coverage. As a result, rapid detection tests (RDTs) have started to gain inroads in medical practice. Rapid detection tests notwithstanding, analysis of blood serum is still a relatively complicated task. This includes the necessity of phlebotomy, centrifugation for blood serum, and other reagent-based tests. Therefore, a non-invasive method of dengue detection was considered. In this study, we present the utility of diffuse reflectance skin spectroscopy (bandwidth of 200-2500nm) on the forearm during the triaging period for dengue screening potential. This is performed with multivariate analysis of 240 triaged febrile/suspected dengue patients. The data is then scrutinized for its clinical validity to be included as either confirmed or probable dengue, or a control group. Based on discriminant analysis of several data normalization models, we can predict the patients' clinical dengue-positivity at ranges of accuracy between ~93-98% depending on mode of the data, with a probably optimal sensitivity and specificity to the clinical diagnosis of ~89% and ~100% respectively. From the outcomes of this study, we recommend further trials with cautious optimism. With these findings, it is hoped that the elusive non-invasive detection of tropical diseases may gain platform in the near future.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Dengue; Female; Humans; Malaysia; Male; Mass Screening; Middle Aged; Multivariate Analysis; Sensitivity and Specificity; Skin; Spectrum Analysis; Young Adult

Several sites, Z-7L, Z-5 and Z-14, in Sibu district, Sarawak, Malaysia, experienced intense dengue transmission in 2014 that continued into 2015. A pilot study with Bacillus thuringiensis israelensis (Bti) to control Aedes aegypti (L.) and Ae. albopictus (Skuse) was evaluated in Z-7L, a densely populated site of 12 ha. Bti treatments were conducted weekly from epidemiology week (EW) 24/2015 for 4 weeks, followed by fortnight treatments for 2 months, in addition to the routine control activities. Bti was directly introduced into potable containers and the outdoor artificial and natural containers were treated via a wide area spray application method using a backpack mister. Aedes indices significantly reduced during the treatment and post treatment phases, compared to the control site, Z-5 (p<0.05). A 51 fold reduction in the incidence rate per 100,000 population (IR) was observed, with one case in 25 weeks (EW 29-52). In Z-5 and Z-14, control sites, a 6 fold reduction in the IR was observed from EW 29-52. However, almost every week there were dengue cases in Z-14 and until EW 44 in Z-5. In 2016, dengue cases resurfaced in Z-7L from EW 4. Intensive routine control activities were conducted, but the IR continued to escalate. The wide area Bti spray misting of the outdoor containers was then included from EW 27 on fortnight intervals. A 6 fold reduction in IR was observed in the Bti treatment phase (EW 32-52) with no successive weekly cases after EW 37. However, in the control sites, there were dengue cases throughout the year from EW 1-52, particularly in Z-14. We feel that the wide area Bti spray application method is an integral component in the control program, in conjunction with other control measures carried out, to suppress the vector population in outdoor cryptic containers and to interrupt the disease transmission.

Topics: Aedes; Animals; Bacillus thuringiensis; Biological Control Agents; Dengue; Disease Reservoirs; Disease Vectors; Insecticides; Larva; Malaysia; Mosquito Control; Mosquito Vectors; Pilot Projects; Prevalence

We report a rare case of severe Plasmodium knowlesi malaria and dengue co-infection in a 36-year-old lady with hyperparasitaemia, metabolic acidosis, haemolysis and acute kidney injury. She was in shock requiring inotropic support and elective intubation. She had pericardial tamponade which necessitate pericardiocentesis to allow for haemodynamic stability during haemodialysis. She underwent haemodialysis, was ventilated for six days and stayed in hospital for 29 days. She was discharged home well with almost complete renal recovery. Physicians must have a high degree of suspicion for dengue co-infection in malaria patients with plasma leakage such as pericardial effusion to allow for prompt management.

Topics: Acute Kidney Injury; Adult; Coinfection; Dengue; Female; Humans; Malaria; Malaysia; Plasmodium knowlesi; Renal Dialysis; Treatment Outcome

In South East Asia, dengue epidemics have increased in size and geographical distribution in recent years. We examined the spatiotemporal distribution and epidemiological characteristics of reported dengue cases in the predominantly rural state of Sabah, in Malaysian Borneo-an area where sylvatic and urban circulation of pathogens are known to intersect. Using a public health data set of routinely notified dengue cases in Sabah between 2010 and 2016, we described demographic and entomological risk factors, both before and after a 2014 change in the clinical case definition for the disease. Annual dengue incidence rates were spatially variable over the 7-year study period from 2010-2016 (state-wide mean annual incidence of 21 cases/100,000 people; range 5-42/100,000), but were highest in rural localities in the western districts of the state (Kuala Penyu, Nabawan, Tenom and Kota Marudu). Eastern districts exhibited lower overall dengue rates, although a high proportion of severe (haemorrhagic) dengue cases (44%) were focused in Sandakan and Tawau. Dengue incidence was highest for those aged between 10 and 29 years (24/100,000), and was slightly higher for males compared to females. Available vector surveillance data indicated that during large outbreaks in 2015 and 2016 the mosquito Aedes albopictus was more prevalent in both urban and rural households (House Index of 64%) than Ae. aegypti (15%). Demographic patterns remained unchanged both before and after the dengue case definition was changed; however, in the years following the change, reported case numbers increased substantially. Overall, these findings suggest that dengue outbreaks in Sabah are increasing in both urban and rural settings. Future studies to better understand the drivers of risk in specific age groups, genders and geographic locations, and to test the potential role of Ae. albopictus in transmission, may help target dengue prevention and control efforts.

Topics: Adolescent; Adult; Aedes; Age Distribution; Animals; Child; Child, Preschool; Dengue; Dengue Virus; Female; Humans; Incidence; Infant; Malaysia; Male; Middle Aged; Mosquito Vectors; Young Adult

Currently, dengue control relies largely on reactive vector control programmes. Proactive vector-control using a rational, well-balanced integrated vector management approach may prove more successful for dengue control. As part of the development of a cluster randomized controlled epidemiological trial, a study was conducted in Johor Bahru, Malaysia. The study included one control site (three buildings) and three intervention sites which were treated as follows: targeted outdoor residual spraying only (TORS site, two buildings); deployment of autodissemination devices only (ADD site, four buildings); and the previous two treatments combined (TORS + ADD site, three buildings). The primary entomological measurement was per cent of positive ovitraps-ovitrap index (OI). The effect of each intervention on OI was analyzed by a modified ordinary least squares regression model. Relative to the control site, the TORS and ADD sites showed a reduction in the Aedes OI (-6.5%, P = 0.04 and -8.3%, P = 0.10, respectively). Analysis by species showed that, relative to control, the Ae. aegypti OI was lower in ADD (-8.9%, P = 0.03) and in TORS (-10.4%, P = 0.02). No such effect was evident in the TORS + ADD site. The present study provides insights into the methods to be used for the main trial. The combination of multiple insecticides with different modes of action in one package is innovative, although we could not demonstrate the additive effect of TORS + ADD. Further work is required to strengthen our understanding of how these interventions impact dengue vector populations and dengue transmission.

Topics: Aedes; Animals; Cities; Dengue; Insecticides; Malaysia; Mosquito Control; Mosquito Vectors

Dengue has become a global public health problem. Despite reactive efforts by the government in Malaysia, the dengue cases are on the increase. Adequate knowledge, positive attitude and correct practice for dengue control are essential to stamp out the disease. Hence, this study aims to assess the factors associated with dengue knowledge, attitude and practice (KAP), as well as the association with dengue IgM and IgG seropositivity. A community-based cross-sectional study was conducted in a closed, dengue endemic area with multi-storey dwellings . Five hundred individuals (aged 18 years and above) were approached for pre-tested KAP and seroprevalences assessment. The study showed only half of the total participants have good knowledge (50.7%) but they had insufficient knowledge about dengue during pregnancy. 53.2% of people had poor attitude and 50.2% reported poor practice for dengue control. Out of 85 respondents who agreed to participate in the dengue seroprevalence study, 74.1% (n = 63) were positive for dengue IgG and 7.1% (n = 6) were positive for dengue IgM. Among all sociodemographic variable, race is the only independent predicator for all KAP levels (P < 0.05). In conclusion, proactive and sustainable efforts are needed to bring a behavioural change among communities in order to fight dengue outbreaks in endemic areas.

Topics: Adult; Cross-Sectional Studies; Dengue; Female; Health Knowledge, Attitudes, Practice; Humans; Malaysia; Male; Seroepidemiologic Studies

Background Dengue is a vector-borne viral disease endemic in Malaysia. The disease is presently a public health issue in the country. Hence, the use of mathematical model to gain insights into the transmission dynamics and derive the optimal control strategies for minimizing the spread of the disease is of great importance. Methods A model involving eight mutually exclusive compartments with the introduction of personal protection, larvicide and adulticide control strategies describing dengue fever transmission dynamics is presented. The control-induced basic reproduction number (R˜

Topics: Aedes; Animals; Dengue; Malaysia; Models, Biological; Mosquito Vectors

A periodic serosurvey of dengue seroprevalence is vital to determine the prevalence of dengue in countries where this disease is endemic. This study aimed to determine the prevalence of dengue immunoglobulin G (IgG) seropositivity among healthy Malaysian adults living in urban and rural areas.. A total of 2598 serum samples (1417 urban samples, 1181 rural samples) were randomly collected from adults ages 35-74 y. The presence of the dengue IgG antibody and neutralising antibodies to dengue virus (DENV) 1-4 was determined using enzyme-linked immunosorbent assay and the plaque reduction neutralisation test assay, respectively.. The prevalence of dengue IgG seropositivity was 85.39% in urban areas and 83.48% in rural areas. The seropositivity increased with every 10-y increase in age. Ethnicity was associated with dengue seropositivity in urban areas but not in rural areas. The factors associated with dengue seropositivity were sex and working outdoors. In dengue IgG-positive serum samples, 98.39% of the samples had neutralising antibodies against DENV3, but only 70.97% of them had neutralising antibodies against DENV4.. The high seroprevalence of dengue found in urban and rural areas suggests that both urban and rural communities are vital for establishing and sustaining DENV transmission in Malaysia.

Topics: Adult; Aged; Antibodies, Viral; Dengue; Dengue Virus; Enzyme-Linked Immunosorbent Assay; Epidemics; Humans; Immunoglobulin G; Malaysia; Middle Aged; Rural Population; Seroepidemiologic Studies

An estimated 105 million dengue infections occur per year across 120 countries, where traditional vector control is the primary control strategy to reduce contact between mosquito vectors and people. The ongoing sars-cov-2 pandemic has resulted in dramatic reductions in human mobility due to social distancing measures; the effects on vector-borne illnesses are not known. Here we examine the pre and post differences of dengue case counts in Malaysia, Singapore and Thailand, and estimate the effects of social distancing as a treatment effect whilst adjusting for temporal confounders. We found that social distancing is expected to lead to 4.32 additional cases per 100,000 individuals in Thailand per month, which equates to 170 more cases per month in the Bangkok province (95% CI: 100-242) and 2008 cases in the country as a whole (95% CI: 1170-2846). Social distancing policy estimates for Thailand were also found to be robust to model misspecification, and variable addition and omission. Conversely, no significant impact on dengue transmission was found in Singapore or Malaysia. Across country disparities in social distancing policy effects on reported dengue cases are reasoned to be driven by differences in workplace-residence structure, with an increase in transmission risk of arboviruses from social distancing primarily through heightened exposure to vectors in elevated time spent at residences, demonstrating the need to understand the effects of location on dengue transmission risk under novel population mixing conditions such as those under social distancing policies.

Topics: Animals; Betacoronavirus; Communicable Disease Control; Coronavirus Infections; COVID-19; Dengue; Humans; Malaysia; Mosquito Vectors; Pandemics; Pneumonia, Viral; SARS-CoV-2; Singapore; Social Isolation; Thailand

An outbreak of dengue in Kudat, northern Sabah in 2016-2017 provided an opportunity to investigate the circulating serotypes of dengue viruses of cases at Hospital Kudat. Between September 2016 and December 2017, a total of 156 dengue positive sera (tested positive by either NS1 antigen, or IgM and IgG antibody rapid test) were collected from dengue patients who had acute fever and showed signs and symptoms suggestive of dengue. RNA was extracted from the sera using QIAamp RNA Blood Mini Kit, and molecular amplification was performed using one-step RT-PCR kit, followed by nested PCR using HotStart Taq master mix kit with the primers of the dengue C-prM gene. There were 81 (52%) male and 75 (48%) female cases. The age group with the highest number of cases was the 10-19 years old, while the youngest infected was 8 months old and the oldest was 83 years old. RT-PCR results showed 88 sera dengue positive, 48 infected with a single serotype while another 40 with multiple serotypes. All four DENV serotypes were co-circulating during the outbreak period and DENV-1 was predominant. Molecular analysis also indicated 69.2%, 50.0%, 51.9% and 48.9% respectively of the NS1, IgM, IgG and IgM and IgG positive sera were RT-PCR positive for dengue. High number of cases were seen in December 2016, February and May 2017. The dengue outbreak might be related to switching of predominant serotype from DENV 4 to DENV 1.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Child; Child, Preschool; Dengue; Dengue Virus; Disease Outbreaks; Female; Humans; Infant; Malaysia; Male; Middle Aged; Serotyping; Young Adult

The continued absence of an effective and safe tetravalent dengue vaccine and the lack of specific anti-viral treatment have made mosquito vector control using chemical insecticides as the mainstream for dengue prevention and control. However, the long-term use of chemical insecticides may induce resistance. Hence detection of insecticide resistance in dengue vectors is crucially important in ensuring the insecticide-based intervention in dengue control program is still effective and reliable. In this study, the susceptibility status of Aedes aegypti from five selected dengue hotspots in Klang Valley, Malaysia against pyrethroids was determined by employing the World Health Organization (WHO) protocol of adult bioassay. Four types of pyrethroids were tested against adult female Aedes aegypti to determine the knockdown rate, post 24-h adult mortality and resistance ratio. All field-collected Aedes aegypti strains were resistant to the four pyrethroids tested, except for the Taman Sungai Jelok (TSJ) strain. Permethrin exhibited the lowest knockdown rate against Aedes aegypti, followed by deltamethrin, cyfluthrin and lambda-cyhalothrin. This present study indicated the widespread of pyrethroid resistance in Aedes aegypti in Klang Valley, indicating the needs of implementing alternative measures in vector control program. The data in this study can be utilised as an input for insecticide resistance management of Aedes aegypti in Malaysia.

Topics: Aedes; Animals; Dengue; Female; Insecticide Resistance; Insecticides; Malaysia; Mosquito Vectors; Pyrethrins

The present study aimed to explore the current status of knowledge and practices of dengue prevention associated with sociodemographic status among the community living in an urban area of Selangor, Malaysia. A total of 441 participants were interviewed regarding sociodemographic status, knowledge of dengue, and self-reported prevention practices. Participants over 40 years old were more likely (odds ratio [OR] = 4.210, 95% CI = 1.652-10.733, P = 0.003) to have better dengue knowledge. Participants whose average monthly household income was more than MYR3,000 (US$715) were more likely (OR = 1.607, 95% CI = 1.059-2.438, P = 0.026) to have better practices of dengue prevention measures. The finding suggests that both government and community efforts are essential in order to continue to educate about dengue and reduce the frequency of dengue cases nationwide.

Topics: Adult; Aedes; Animals; Cross-Sectional Studies; Dengue; Health Knowledge, Attitudes, Practice; Humans; Malaysia; Mosquito Vectors; Socioeconomic Factors; Urban Population; Young Adult

Natural reservoir hosts can sustain infection of pathogens without succumbing to overt disease. Multiple bat species host a plethora of viruses, pathogenic to other mammals, without clinical symptoms. Here, we detail infection of bat primary cells, immune cells, and cell lines with Dengue virus. While antibodies and viral RNA were previously detected in wild bats, their ability to sustain infection is not conclusive. Old-world fruitbat cells can be infected, producing high titres of virus with limited cellular responses. In addition, there is minimal interferon (IFN) response in cells infected with MOIs leading to dengue production. The ability to support in vitro replication/production raises the possibility of bats as a transient host in the life cycle of dengue or similar flaviviruses. New antibody serology evidence from Asia/Pacific highlights the previous exposure and raises awareness that bats may be involved in flavivirus dynamics and infection of other hosts.

Topics: Animals; Australasia; Cell Line; Chiroptera; Dengue; Dengue Virus; Host-Pathogen Interactions; Immunity, Innate; Malaysia; Virus Internalization

The frequency of travel-related infections in the world has increased due to the easily and widespread use of travel facilities in the 21st century. Vector-borne diseases are an important part of infectious diseases. Dengue fever is one of the travel-related infections that has been reported increasingly in recent years through the development of diagnostic methods. The aim of this report was to present two Dengue fever cases originating from travel. There was a story of mosquito bite during a trip to Sri Lanka travel in our first case. The patient was 30 years old and maculopapular rash appeared on the fifth day of contact. Three days after the onset of the rash, she has admitted to our clinic, complaining with fever and chills. Increased leukopenia and muscle enzymes were detected in the laboratory analysis. Real-time reverse transcriptase polimerase chain reaction (RT-PCR) was positive in the serum sample. The patient was followed up with supportive care and discharged by improvement. The second case, a 24-year-old male, had a story of mosquito bite during his trip to Malaysia. After the patient complained of fever, chills, fever, nausea, vomiting and muscle pain, the Dengue virus (DENV) NS1 antigen test performed in this country was found to be positive. In the second case, there was no maculopapular rash and laboratory analysis showed an increase in leukopenia, thrombocytopenia and muscle enzymes. RT-PCR positivity was detected in the serum sample. The patient was followed up with supportive treatment and discharged with cure. DENV infections are caused by DENV which is common in the tropical areas of the world. There are four DENV-1, DENV-2, DENV-3 and DENV-4 serotypes. DENV infections can present different clinical manifestations such as asymptomatic disease, viral syndrome, Dengue haemorrhagic fever, and Dengue shock syndrome. Dengue fever is often accompanied by arthritis, maculopapular rash and high fever. Our cases were defined as Dengue fever according to this definition. In the diagnosis of the disease, it is necessary first to be suspicious of the disease and the travel history must be questioned. In the definitive diagnosis, virus isolation, antigen, nucleic acid detection and serological tests are used. The virus can be isolated from blood, serum, urine and tissues. In the first five days after beginning of the symptoms associated with DENV infections, serum RT-PCR and Dengue NS1 antigen test may be positive.

Topics: Adult; Dengue; Dengue Virus; Exanthema; Female; Humans; Malaysia; Male; Sri Lanka; Travel-Related Illness; Treatment Outcome; Young Adult

The world's first dengue vaccine [Dengvaxia; Sanofi Pasteur] was licensed in 2015 and others are in development. Real-world evaluations of dengue vaccines will therefore soon be needed. We assessed feasibility of case control (CC) and test-negative (TN) design studies for dengue vaccine effectiveness by measuring associations between socio-demographic risk factors, and hospitalized dengue outcomes, in Malaysia.. Following ethical approval, we conducted hospital-based dengue surveillance for one year in three referral hospitals. Suspected cases aged 9-25 years underwent dengue virological confirmation by RT-PCR and/or NS1 Ag ELISA at a central laboratory. Two age- and geography-matched hospitalized non-dengue case-controls were recruited for a traditional CC study. Suspected cases testing negative were test-negative controls. Socio-demographic, risk factor and routine laboratory data were collected. Logistic regression models were used to estimate associations between confirmed dengue and risk factors.. We recruited 327 subjects; 155 were suspected of dengue. The planned sample size was not met. 124 (80%) of suspected cases were dengue-confirmed; seven were assessed as severe. Three had missing RT-PCR results; the study recruited 28 test-negative controls. Only 172 matched controls could be recruited; 90 cases were matched with ≥1 controls. Characteristics of cases and controls were mostly similar. By CC design, two variables were significant risk factors for hospitalized dengue: recent household dengue contact (OR: 54, 95% CI: 7.3-397) and recent neighbourhood insecticidal fogging (OR: 2.1; 95% CI: 1.3-3.6). In the TN design, no risk factors were identified. In comparison with gold-standard diagnostics, routine tests performed poorly.. The CC design may be more appropriate than the TN design for hospitalized dengue vaccine effectiveness studies. Selection bias in case control selection could be minimized by protocol changes more easily than increasing TN design control numbers, because early-stage dengue diagnosis in endemic countries is highly specific. MREC study approval: (39)KKM/NIHSEC/P16-1334.

Topics: Adolescent; Adult; Case-Control Studies; Dengue; Dengue Vaccines; Dengue Virus; Feasibility Studies; Female; Humans; Malaysia; Male; Young Adult

Dengue has enormous health impacts globally. A novel approach to decrease dengue incidence involves the introduction of Wolbachia endosymbionts that block dengue virus transmission into populations of the primary vector mosquito, Aedes aegypti. The wMel Wolbachia strain has previously been trialed in open releases of Ae. aegypti; however, the wAlbB strain has been shown to maintain higher density than wMel at high larval rearing temperatures. Releases of Ae. aegypti mosquitoes carrying wAlbB were carried out in 6 diverse sites in greater Kuala Lumpur, Malaysia, with high endemic dengue transmission. The strain was successfully established and maintained at very high population frequency at some sites or persisted with additional releases following fluctuations at other sites. Based on passive case monitoring, reduced human dengue incidence was observed in the release sites when compared to control sites. The wAlbB strain of Wolbachia provides a promising option as a tool for dengue control, particularly in very hot climates.

Topics: Aedes; Animals; Dengue; Dengue Virus; Female; Humans; Insect Vectors; Malaysia; Male; Mosquito Vectors; Pest Control, Biological; Wolbachia

Japanese encephalitis virus (JEV) is a zoonotic, mosquito-borne flavivirus, distributed across Asia. Infections are mostly mild or asymptomatic, but symptoms include neurological disorders, sequelae, and fatalities. Data to inform control strategies are limited due to incomplete case reporting.. We used JEV serological data from a multicountry Asian dengue vaccine study in children aged 2-14 years to describe JEV endemicity, measuring antibodies by plaque reduction neutralization test (PRNT50).. A total 1479 unvaccinated subjects were included. A minimal estimate of pediatric JEV seroprevalence in dengue-naive individuals was 8.1% in Indonesia, 5.8% in Malaysia, 10.8% in the Philippines, and 30.7% in Vietnam, translating to annual infection risks varying from 0.8% (in Malaysia) to 5.2% (in Vietnam). JEV seroprevalence and annual infection estimates were much higher in children with history of dengue infection, indicating cross-neutralization within the JEV PRNT50 assay.. These data confirm JEV transmission across predominantly urban areas and support a greater emphasis on JEV case finding, diagnosis, and prevention.

Topics: Adolescent; Asia; Child; Child, Preschool; Dengue; Dengue Vaccines; Dengue Virus; Encephalitis Virus, Japanese; Encephalitis, Japanese; Humans; Indonesia; Malaysia; Neutralization Tests; Philippines; Prevalence; Seroepidemiologic Studies; Vietnam

Malaysia has rising dengue incidence. World Health Organization clinical practice guidelines for managing dengue have been adapted by the Ministry of Health in Malaysia, with evidence of good awareness by clinicians. However, dengue mortality has not reduced. This study aimed to explore the challenges of dengue management for Medical Officers, with a particular focus on use of clinical practice guidelines.. Qualitative study using six focus groups and 14 semi-structured interviews with doctors responsible for dengue management at a large tertiary hospital in Malaysia.. Dengue was recognised as difficult to diagnose and manage. Wide awareness and use of both WHO and Ministry of Health guidelines was reported, but several limitations noted in their coverage of particular patient groups. However, the phrase 'guidelines' also referred to local algorithms for fluid management, which were less clinically evidence-based. Where Medical Officers were well trained in the appropriate use of evidence-based guidelines, barriers to use included: the potential for 'following the algorithm' to undermine junior clinicians' claims to clinical expertise; inability to recognise the pattern of clinical progress; and lack of clinical experience. Other reported barriers to improved case management were resource constraints, poor referral practices, and insufficient awareness of the need for timely help seeking.. Awareness of clinical practice guidelines is a necessary, but not sufficient, condition for optimal dengue management. In high prevalence settings, all clinical staff would benefit from regular dengue management training which should include diagnosis, practice in monitoring disease progression and the use of clinical practice guidelines in a range of clinical contexts.

Topics: Dengue; Focus Groups; Health Personnel; Humans; Malaysia; Physicians; Practice Guidelines as Topic; Referral and Consultation; Tertiary Care Centers; World Health Organization

Topics: Adolescent; Adult; Aged; Child; Dengue; Dengue Virus; Diabetes Complications; Female; Fever; Humans; Length of Stay; Logistic Models; Malaysia; Male; Middle Aged; Retrospective Studies; Serogroup; Tertiary Care Centers; Viral Nonstructural Proteins

An early warning system for dengue is meant to predict outbreaks and prevent dengue cases by aiding timely decision making and deployment of interventions. However, only a system which is accepted and utilised by the public would be sustainable in the long run. This study aimed to explore the perception and attitude of the Malaysian public towards a dengue early warning system. The sample consisted of 847 individuals who were 18 years and above and living/working in the Petaling District, an area adjacent to Kuala Lumpur, Malaysia. A questionnaire consisting of personal information and three sub-measures of; i) perception, ii) attitude towards dengue early warning and iii) response towards early warning; was distributed to participants. We found that most of the respondents know about dengue fever (97.1%) and its association with climate factors (90.6%). Most of them wanted to help reduce the number of dengue cases in their area (91.5%). A small percentage of the respondents admitted that they were not willing to be involved in public activities, and 64% of them admitted that they did not check dengue situations or hotspots around their area regularly. Despite the high awareness on the relationship between climate and dengue, about 45% of respondents do not know or are not sure how this can be used to predict dengue. Respondents would like to know more about how climate data can be used to predict a dengue outbreak (92.7%). Providing more information on how climate can influence dengue cases would increase public acceptability and improve response towards climate-based warning system. The most preferred way of communicating early warning was through the television (66.4%). This study shows that the public in Petaling District considers it necessary to have a dengue warning system to be necessary, but more education is required.

Topics: Adolescent; Adult; Aged; Attitude to Health; Climate; Cross-Sectional Studies; Decision Making; Dengue; Disease Outbreaks; Female; Health Knowledge, Attitudes, Practice; Humans; Malaysia; Male; Middle Aged; Public Opinion; Socioeconomic Factors; Surveys and Questionnaires; Young Adult

Increasing incidences of dengue have become a global health threat with major clinical manifestation including high fever and gastrointestinal symptoms. These symptoms were also expressed among Blastocystis sp. infected individuals, a parasite commonly seen in human stools. This parasite has been previously reported to replicate faster upon exposure to high temperature. The present study is a hospitalized-based cross-sectional study involved the collection of faecal sample from dengue patients. Stool examination was done by in vitro cultivation to isolate Blastocystis sp. Growth pattern of all the positive isolates were analyzed to identify the multiplication rate of Blastocystis sp. isolated from dengue patients. Distribution of Blastocystis sp. among dengue patients was 23.6%. Dengue patients who were positive for Blastocystis sp. infection denoted a significantly higher fever rate reaching 38.73°C (p<0.05) compared to the non-Blastocystis sp. infected patients (38.44°C). It was also found that Blastocystis sp. infected patients complained of frequenting the toilet more than five times a day (p<0.05) compared to those who were non-Blastocystis sp. infected. At the same time, the duration of hospitalization was significantly longer (p<0.05) for Blastocystis sp. infected dengue patients compared to the non-Blastocystis sp. infected patients. Besides, Blastocystis sp. isolated from dengue patients (in vivo thermal stress) showed a higher growth rate compared to the non-dengue isolated which was exposed to high temperature (in vitro thermal stress). Our findings suggest that presence of Blastocystis sp. during dengue infection could trigger the increase of temperature which could be due to highly elevated pro inflammatory cytokines by both parasitic and virus infection. This could justify why the temperature in Blastocystis sp. infected dengue patients is higher compared to the non-Blastocystis sp. infected patients. Higher temperature could have triggered a greater parasite multiplication rate that contributed to the aggravation of the gastrointestinal symptoms.

Topics: Adult; Blastocystis; Blastocystis Infections; Cross-Sectional Studies; Dengue; Feces; Female; Fever; Gastrointestinal Diseases; Health Care Costs; Humans; Malaysia; Male

Topics: Adolescent; Adult; Aged; Comorbidity; Dengue; Female; Guillain-Barre Syndrome; Humans; Malaysia; Male; Middle Aged; Nervous System Diseases; Young Adult

Dengue is a serious public health problem worldwide, including in Selangor, Malaysia. Being an important vector of dengue virus, Aedes aegypti are subjected to control measures which rely heavily on the usage of insecticides. Evidently, insecticide resistance in Ae. aegypti, which arise from several different point mutations within the voltage-gated sodium channel genes, has been documented in many countries. Thus, this robust study was conducted in all nine districts of Selangor to understand the mechanisms of resistance to various insecticides in Ae. aegypti. Mosquitoes were collected from dengue epidemic and non-dengue outbreak areas in Selangor.. Using the Center for Disease Control and Prevention (CDC) bottle assays, the insecticide resistance status of nine different Ae. aegypti strains from Selangor was accessed. Synergism tests and biochemical assays were conducted to further understand the metabolic mechanisms of insecticide resistance. Polymerase chain reaction (PCR) amplification and sequencing of the IIP-IIS6 as well as IIIS4-IIIS6 regions of the sodium channel gene were performed to enable comparisons between susceptible and resistant mosquito strains. Additionally, genomic DNA was used for allele-specific PCR (AS-PCR) genotyping of the gene to detect the presence of F1534C, V1016G and S989P mutations.. Adult female Ae. aegypti from various locations were susceptible to malathion and propoxur. However, they exhibited different levels of resistance against dichlorodiphenyltrichloroethane (DDT) and pyrethroids. The results of synergism tests and biochemical assays indicated that the mixed functions of oxidases and glutathione S-transferases contributed to the DDT and pyrethroid resistance observed in the present study. Besides detecting three single kdr mutations, namely F1534C, V1016G and S989P, co-occurrence of homozygous V1016G/S989P (double allele) and F1534C/V1016G/S989P (triple allele) mutations were also found in Ae. aegypti. As per the results, the three kdr mutations had positive correlations with the expressions of resistance to DDT and pyrethroids.. In view of the above outcomes, it is important to seek new tools for vector management instead of merely relying on insecticides. If the latter must be used, regular monitoring of insecticide resistance should also be carried out at all dengue epidemic areas. Since the eggs of Ae. aegypti can be easily transferred from one location to another, it is probable that insecticide-resistant Ae. aegypti can be found at non-dengue outbreak sites as well.

Topics: Aedes; Alleles; Animals; Dengue; Female; Genotype; Glutathione Transferase; Insect Proteins; Insecticide Resistance; Insecticides; Malathion; Malaysia; Mosquito Vectors; Mutation; Oxidoreductases; Polymerase Chain Reaction; Pyrethrins; Sequence Analysis, DNA; Sodium Channels

Dengue is fast becoming the most urgent health issue in Malaysia, recording close to a 10-fold increase in cases over the last decade. With much uncertainty hovering over the recently introduced tetravalent vaccine and no effective antiviral drugs, vector control remains the most important strategy in combating dengue. This study analyses the relationship between weather predictors including its lagged terms, and dengue incidence in the District of Tawau over a period of 12 years, from 2006 to 2017. A forecasting model purposed to predict future outbreaks in Tawau was then developed using this data. Monthly dengue incidence data, mean temperature, maximum temperature, minimum temperature, mean relative humidity and mean rainfall over a period of 12 years from 2006 to 2017 in Tawau were retrieved from Tawau District Health Office and the Malaysian Meteorological Department. Cross-correlation analysis between weather predictors, lagged terms of weather predictors and dengue incidences established statistically significant cross-correlation between lagged periods of weather predictors-namely maximum temperature, mean relative humidity and mean rainfall with dengue incidence at time lags of 4-6 months. These variables were then employed into 3 different methods: a multivariate Poisson regression model, a Seasonal Autoregressive Integrated Moving Average (SARIMA) model and a SARIMA with external regressors for selection. Three models were selected but the SARIMA with external regressors model utilising maximum temperature at a lag of 6 months (p-value:0.001), minimum temperature at a lag of 4 months (p-value:0.01), mean relative humidity at a lag of 2 months (p-value:0.001), and mean rainfall at a lag of 6 months (p-value:0.001) produced an AIC of 841.94, and a log-likelihood score of -413.97 establishing it as the best fitting model of the methodologies utilised. In validating the models, they were utilised to develop forecasts with the model selected with the highest accuracy of predictions being the SARIMA model predicting 1 month in advance (MAE: 7.032, MSE: 83.977). This study establishes the effect of weather on the intensity and magnitude of dengue incidence as has been previously studied. A prediction model remains a novel method of evidence-based forecasting in Tawau, Sabah. The model developed in this study, demonstrated an ability to forecast potential dengue outbreaks 1 to 4 months in advance. These findings are not dissimilar to what has been prev

Topics: Climate; Dengue; Forecasting; Humans; Incidence; Malaysia; Models, Statistical; Poisson Distribution; Weather

Zika virus (ZIKV) is believed to be endemic in Southeast Asia. However, there have been few Zika cases reported to date in Malaysia, which could be due to high pre-existing levels of population immunity.. To determine Zika virus (ZIKV) seroprevalence in Kuala Lumpur, Malaysia, 1085 serum samples from 2012, 2014-2015 and 2017 were screened for anti-ZIKV antibodies using a ZIKV NS1 blockade-of-binding assay. Reactive samples were confirmed using neutralization assays against ZIKV and the four dengue virus (DENV) serotypes. A sample was possible ZIKV seropositive with a ZIKV 50% neutralization (NT50) titre ≥20. A sample was probable ZIKV seropositive if, in addition, all DENV NT50 titres were <20 or the ZIKV NT50 titre was >4-fold greater than the highest DENV NT50 titre.. We found low rates of possible ZIKV seropositivity (3.3% [95% confidence interval {CI} 2.4 to 4.6]) and probable ZIKV seropositivity (0.6% [95% CI 0.3 to 1.4]). Possible ZIKV seropositivity was independently associated with increasing age (odds ratio [OR] 1.04 [95% CI 1.02 to 1.06], p<0.0001) and male gender (OR 3.5 [95% CI 1.5 to 8.6], p=0.005).. The low ZIKV seroprevalence rate, a proxy for population immunity, does not explain the low incidence of Zika in dengue-hyperendemic Kuala Lumpur. Other factors, such as the possible protective effects of pre-existing flavivirus antibodies or reduced transmission by local mosquito vectors, should be explored. Kuala Lumpur is at high risk of a large-scale Zika epidemic.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Antibodies, Viral; Child; Dengue; Dengue Virus; Female; Humans; Malaysia; Male; Middle Aged; Prevalence; Seroepidemiologic Studies; Young Adult

The frequency and magnitude of dengue epidemics continue to increase exponentially in Malaysia, with a shift in the age range predominance toward adults and an expansion to rural areas. Despite this, information pertaining to the extent of transmission of dengue virus (DENV) in the rural community is lacking. This community-based pilot study was conducted to establish DENV seroprevalence amongst healthy adults in a rural district in Southern Malaysia, and to identify influencing factors.. In this study undertaken between April and May 2015, a total of 277 adult participants were recruited from households across three localities in the Sungai Segamat subdistrict in Segamat district. Sera were tested for immunoglobulin G (IgG) (Panbio® Dengue Indirect IgG ELISA/high-titer capture) and immunoglobulin M (IgM) (Panbio®) antibodies. The plaque reduction neutralization test (PRNT) was conducted on random samples of IgG-positive sera for further confirmation. Medical history and a recall of previous history of dengue were collected through interviews, whereas sociodemographic information was obtained from an existing database.. The overall seroprevalence for DENV infection was 86.6% (240/277) (95% CI: 83-91%). Serological evidence of recent infection (IgM/high-titer capture IgG) was noted in 11.2% (31/277) of participants, whereas there was evidence of past infection in 75.5% (209/277) of participants (indirect IgG minus recent infections). The PRNT assay showed that the detected antibodies were indeed specific to DENV. The multivariate analysis showed that the older age group was significantly associated with past DENV infections. Seropositivity increased with age; 48.5% in the age group of <25 years to more than 85% in age group of >45 years (P < 0.001). No associations with occupation, study site, housing type, comorbidity, educational level, and marital status were observed, although the latter two were statistically significant in the univariate analysis. None of the studied factors were significantly associated with recent DENV infections in the multivariate analysis, although there was a pattern suggestive of recent outbreak in two study sites populated predominately by Chinese people. The majority of infections did not give rise to recognizable disease (either asymptomatic or nonspecific symptoms) as only 12.9% of participants (31/240) recalled having dengue in the past.. The predominantly rural community under study had a very high previous exposure to dengue. The finding of a high proportion of unreported cases possibly due to subclinical infections underscores the need for enhanced surveillance and control methods. This finding also has implications for measuring disease burden, understanding transmission dynamics, and hypothesizing effects on DENV vaccine efficacy and uptake.

Topics: Adult; Age Factors; Antibodies, Viral; Dengue; Dengue Virus; Disease Outbreaks; Enzyme-Linked Immunosorbent Assay; Female; Healthy Volunteers; Humans; Immunoglobulin G; Immunoglobulin M; Malaysia; Male; Middle Aged; Pilot Projects; Residence Characteristics; Rural Population; Seroepidemiologic Studies

A large scale study was conducted to elucidate the true relationship among entomological, epidemiological and environmental factors that contributed to dengue outbreak in Malaysia. Two large areas (Selayang and Bandar Baru Bangi) were selected in this study based on five consecutive years of high dengue cases. Entomological data were collected using ovitraps where the number of larvae was used to reflect Aedes mosquito population size; followed by RT-PCR screening to detect and serotype dengue virus in mosquitoes. Notified cases, date of disease onset, and number and type of the interventions were used as epidemiological endpoint, while rainfall, temperature, relative humidity and air pollution index (API) were indicators for environmental data. The field study was conducted during 81 weeks of data collection. Correlation and Autoregressive Distributed Lag Model were used to determine the relationship. The study showed that, notified cases were indirectly related with the environmental data, but shifted one week, i.e. last 3 weeks positive PCR; last 4 weeks rainfall; last 3 weeks maximum relative humidity; last 3 weeks minimum and maximum temperature; and last 4 weeks air pollution index (API), respectively. Notified cases were also related with next week intervention, while conventional intervention only happened 4 weeks after larvae were found, indicating ample time for dengue transmission. Based on a significant relationship among the three factors (epidemiological, entomological and environmental), estimated Autoregressive Distributed Lag (ADL) model for both locations produced high accuracy 84.9% for Selayang and 84.1% for Bandar Baru Bangi in predicting the actual notified cases. Hence, such model can be used in forestalling dengue outbreak and acts as an early warning system. The existence of relationships among the entomological, epidemiological and environmental factors can be used to build an early warning system for the prediction of dengue outbreak so that preventive interventions can be taken early to avert the outbreaks.

Topics: Aedes; Animals; Dengue; Dengue Virus; Disease Outbreaks; Female; Humans; Larva; Malaysia; Male; Models, Biological; Mosquito Vectors

Hospitalization due to dengue illness is an important measure of dengue morbidity. However, limited studies are based on administrative database because the validity of the diagnosis codes is unknown. We validated the International Classification of Diseases, 10th revision (ICD) diagnosis coding for dengue infections in the Malaysian Ministry of Health's (MOH) hospital discharge database.. This validation study involves retrospective review of available hospital discharge records and hand-search medical records for years 2010 and 2013. We randomly selected 3219 hospital discharge records coded with dengue and non-dengue infections as their discharge diagnoses from the national hospital discharge database. We then randomly sampled 216 and 144 records for patients with and without codes for dengue respectively, in keeping with their relative frequency in the MOH database, for chart review. The ICD codes for dengue were validated against lab-based diagnostic standard (NS1 or IgM).. The ICD-10-CM codes for dengue had a sensitivity of 94%, modest specificity of 83%, positive predictive value of 87% and negative predictive value 92%. These results were stable between 2010 and 2013. However, its specificity decreased substantially when patients manifested with bleeding or low platelet count.. The diagnostic performance of the ICD codes for dengue in the MOH's hospital discharge database is adequate for use in health services research on dengue.

Topics: Adolescent; Adult; Aged; Child; Child, Preschool; Databases, Factual; Dengue; Female; Hospital Records; Hospitalization; Humans; International Classification of Diseases; Malaysia; Male; Middle Aged; Patient Discharge; Retrospective Studies; Young Adult

Dengue virus type 3 genotype III (DENV3/III) is associated with increased number of severe infections when it emerged in the Americas and Asia. We had previously demonstrated that the DENV3/III was introduced into Malaysia in the late 2000s. We investigated the genetic diversity of DENV3/III strains recovered from Malaysia and examined their phylogenetic relationships against other DENV3/III strains isolated globally.. Phylogenetic analysis revealed at least four distinct DENV3/III lineages. Two of the lineages (DENV3/III-B and DENV3/III-C) are current actively circulating whereas the DENV3/III-A and DENV3/III-D were no longer recovered since the 1980s. Selection pressure analysis revealed strong evidence of positive selection on a number of amino acid sites in PrM, E, NS1, NS2a, NS2b, NS3, NS4a, and NS5. The Malaysian DENV3/III isolates recovered in the 1980s (MY.59538/1987) clustered into DENV3/III-B, which was the lineage with cosmopolitan distribution consisting of strains actively circulating in the Americas, Africa, and Asia. The Malaysian isolates recovered after the 2000s clustered within DENV3/III-C. This DENV3/III-C lineage displayed a more restricted geographical distribution and consisted of isolates recovered from Asia, denoted as the Asian lineage. Amino acid variation sites in NS5 (NS5-553I/M, NS5-629 T, and NS5-820E) differentiated the DENV3/III-C from other DENV3 viruses. The codon 629 of NS5 was identified as a positively selected site. While the NS5-698R was identified as unique to the genome of DENV3/III-C3. Phylogeographic results suggested that the recent Malaysian DENV3/III-C was likely to have been introduced from Singapore in 2008 and became endemic. From Malaysia, the virus subsequently spread into Taiwan and Thailand in the early part of the 2010s and later reintroduced into Singapore in 2013.. Distinct clustering of the Malaysian old and new DENV3/III isolates suggests that the currently circulating DENV3/III in Malaysia did not descend directly from the strains recovered during the 1980s. Phylogenetic analyses and common genetic traits in the genome of the strains and those from the neighboring countries suggest that the Malaysian DENV3/III is likely to have been introduced from the neighboring regions. Malaysia, however, serves as one of the sources of the recent regional spread of DENV3/III-C3 within the Asia region.

Topics: Amino Acid Substitution; Dengue; Dengue Virus; Genetic Variation; Genotype; Geography; Humans; Internationality; Malaysia; Open Reading Frames; Phylogeny; Phylogeography; Selection, Genetic

Dengue outbreaks are increasing in frequency over space and time, affecting people's health and burdening resource-constrained health systems. The ability to detect early emerging outbreaks is key to mounting an effective response. The early warning and response system (EWARS) is a toolkit that provides countries with early-warning systems for efficient and cost-effective local responses. EWARS uses outbreak and alarm indicators to derive prediction models that can be used prospectively to predict a forthcoming dengue outbreak at district level.. We report on the development of the EWARS tool, based on users' recommendations into a convenient, user-friendly and reliable software aided by a user's workbook and its field testing in 30 health districts in Brazil, Malaysia and Mexico.. 34 Health officers from the 30 study districts who had used the original EWARS for 7 to 10 months responded to a questionnaire with mainly open-ended questions. Qualitative content analysis showed that participants were generally satisfied with the tool but preferred open-access vs. commercial software. EWARS users also stated that the geographical unit should be the district, while access to meteorological information should be improved. These recommendations were incorporated into the second-generation EWARS-R, using the free R software, combined with recent surveillance data and resulted in higher sensitivities and positive predictive values of alarm signals compared to the first-generation EWARS. Currently the use of satellite data for meteorological information is being tested and a dashboard is being developed to increase user-friendliness of the tool. The inclusion of other Aedes borne viral diseases is under discussion.. EWARS is a pragmatic and useful tool for detecting imminent dengue outbreaks to trigger early response activities.

Topics: Aedes; Animals; Brazil; Cost-Benefit Analysis; Dengue; Disease Outbreaks; Humans; Malaysia; Mexico; Models, Statistical; Population Surveillance; Software

The resistance status of Selangor Aedes aegypti (Linnaeus) larvae against four major groups of insecticides (i.e., organochlorines, carbamates, organophosphates and pyrethroids) was investigated. Aedes aegypti were susceptible against temephos (organophosphate), although resistance (RR

Topics: Acetylcholinesterase; Aedes; Animals; Carbamates; Dengue; Disease Outbreaks; Esterases; Female; Glutathione Transferase; Hydrocarbons, Chlorinated; Insecticide Resistance; Insecticides; Larva; Malaysia; Mixed Function Oxygenases; Mosquito Vectors; Organophosphates; Pesticide Synergists; Pyrethrins

This study investigated the potential relationship between dengue cases and air quality - as measured by the Air Pollution Index (API) for five zones in the state of Selangor, Malaysia. Dengue case patterns can be learned using prediction models based on feedback (lagged terms). However, the question whether air quality affects dengue cases is still not thoroughly investigated based on such feedback models. This work developed dengue prediction models using the autoregressive integrated moving average (ARIMA) and ARIMA with an exogeneous variable (ARIMAX) time series methodologies with API as the exogeneous variable. The Box Jenkins approach based on maximum likelihood was used for analysis as it gives effective model estimates and prediction. Three stages of model comparison were carried out for each zone: first with ARIMA models without API, then ARIMAX models with API data from the API station for that zone and finally, ARIMAX models with API data from the zone and spatially neighbouring zones. Bayesian Information Criterion (BIC) gives goodness-of-fit versus parsimony comparisons between all elicited models. Our study found that ARIMA models, with the lowest BIC value, outperformed the rest in all five zones. The BIC values for the zone of Kuala Selangor were -800.66, -796.22, and -790.5229, respectively, for ARIMA only, ARIMAX with single API component and ARIMAX with API components from its zone and spatially neighbouring zones. Therefore, we concluded that API levels, either temporally for each zone or spatio- temporally based on neighbouring zones, do not have a significant effect on dengue cases.

Topics: Air Pollutants; Bayes Theorem; Dengue; Malaysia; Models, Statistical; Spatial Analysis

Increasing numbers of dengue infection worldwide have led to a rise in deaths due to complications caused by this disease. We present here a cross-sectional study of dengue patients who attended the Emergency and Trauma Department of Ampang Hospital, one of Malaysia's leading specialist hospitals. The objective was to search for potential clustering of severe dengue, in space and/or time, among the annual admissions with the secondary objective to describe the spatio-temporal pattern of all dengue cases admitted to this hospital. The dengue status of the patients was confirmed serologically with the geographic location of the patients determined by residency, but not more specific than the street level. A total of 1165 dengue patients were included in the analysis using SaTScan software. The mean age of these patients was 27.8 years, with a standard deviation of 14.2 years and an age range from 1 to 77 years, among whom 54 (4.6%) were cases of severe dengue. A cluster of general dengue cases was identified occurring from October to December in the study year of 2015 but the inclusion of severe dengue in that cluster was not statistically significant (P=0.862). The standardized incidence ratio was 1.51. General presence of dengue cases was, however, detected to be concentrated at the end of the year, which should be useful for hospital planning and management if this pattern holds.

Topics: Adolescent; Adult; Aged; Child; Child, Preschool; Cross-Sectional Studies; Dengue; Female; Hospitalization; Hospitals, Special; Humans; Infant; Malaysia; Male; Middle Aged; Space-Time Clustering; Spatial Analysis; Young Adult

Epidemiologic measures of the dengue burden such as prevalence and incidence are important for policy-making and monitoring the progress of disease control. It is a common practice where epidemiologic and economic research estimate dengue burden based on notification data. However, a basic challenge in estimating the incidence of dengue is that a significant proportion of infected population are asymptomatic. It can be overcome by using mathematical models that relate observed prevalence and mortality to incidence. In this study, we estimate the trend of dengue incidence and hospitalization in Malaysia.. This study is based entirely on the available secondary data sources on dengue in Malaysia. The age-specific incidence of dengue between 2001 and 2013 was estimated using the prevalence and mortality estimates in an incidence-prevalence-mortality (IPM) model. Data on dengue prevalence were extracted from six sero-surveys conducted in Malaysia between 2001 and 2013; while statistics on dengue notification and Case Fatality Rate were derived from National Dengue Surveillance System. Dengue hospitalization data for the years 2009 to 2013 were extracted from the Health Informatics Centre and the volumes of dengue hospitalization for hospitals with missing data were estimated with Poisson models.. The dengue incidence in Malaysia varied from 69.9 to 93.4 per 1000 population (pkp) between 2001 and 2013.The temporal trend in incidence rate was decreasing since 2001. It has been reducing at an average rate of 2.57 pkp per year from 2001 to 2013 (p = 0.011). The age-specific incidence of dengue decreased steadily with dengue incidence reaching zero by age > 70 years. Dengue notification rate has remained stable since 2001 and the number of notified cases each year was only a small fraction of the incident cases (0.7 to 2.3%). Similarly, the dengue hospitalization was larger but still a small fraction of the incident cases (3.0 to 5.6%).. Dengue incidence can be estimated with the use of sero-prevalence surveys and mortality data. This study highlights a reducing trend of dengue incidence in Malaysia and demonstrates the discrepancy between true dengue disease burden and cases reported by national surveillance system. Sero-prevalence studies with representative samples should be conducted regularly to allow better estimation of dengue burden in Malaysia.

Topics: Adolescent; Adult; Age Distribution; Aged; Child; Child, Preschool; Dengue; Female; Hospitalization; Humans; Incidence; Infant; Infant, Newborn; Information Storage and Retrieval; Malaysia; Male; Middle Aged; Models, Theoretical; Policy Making; Population Surveillance; Prevalence; Residence Characteristics; Selection Bias; Seroepidemiologic Studies; Young Adult

Malaysia experienced an unprecedented dengue outbreak from the year 2014 to 2016 that resulted in an enormous increase in the number of cases and mortality as compared to previous years. The causes that attribute to a dengue outbreak can be multifactorial. Viral factors, such as dengue serotype and genotype, are the components of interest in this study. Although only a small number of studies investigated the association between the serotype of dengue virus and clinical manifestations, none of these studies included analyses on dengue genotypes. The present study aims to investigate dengue serotype and genotype-specific clinical characteristics among dengue fever and severe dengue cases from two Malaysian tertiary hospitals between 2014 and mid-2017.. A total of 120 retrospective dengue serum specimens were subjected to serotyping and genotyping by Taqman Real-Time RT-PCR, sequencing and phylogenetic analysis. Subsequently, the dengue serotype and genotype data were statistically analyzed for 101 of 120 corresponding patients' clinical manifestations to generate a descriptive relation between the genetic components and clinical outcomes of dengue infected patients. During the study period, predominant dengue serotype and genotype were found to be DENV 1 genotype I. Additionally, non-severe clinical manifestations were commonly observed in patients infected with DENV 1 and DENV 3. Meanwhile, patients with DENV 2 infection showed significant warning signs and developed severe dengue (p = 0.007). Cases infected with DENV 2 were also commonly presented with persistent vomiting (p = 0.010), epigastric pain (p = 0.018), plasma leakage (p = 0.004) and shock (p = 0.038). Moreover, myalgia and arthralgia were highly prevalent among DENV 3 infection (p = 0.015; p = 0.014). The comparison of genotype-specific clinical manifestations showed that DENV 2 Cosmopolitan was significantly common among severe dengue patients. An association was also found between genotype I of DENV 3 and myalgia. In a similar vein, genotype III of DENV 3 was significantly common among patients with arthralgia.. The current data contended that different dengue serotype and genotype had caused distinct clinical characteristics in infected patients.

Topics: Adolescent; Child; Dengue; Dengue Virus; Female; Genotype; Genotyping Techniques; Humans; Malaysia; Male; Phylogeny; Real-Time Polymerase Chain Reaction; Retrospective Studies; Reverse Transcriptase Polymerase Chain Reaction; Sequence Analysis, DNA; Serogroup; Serotyping; Tertiary Care Centers; Young Adult

Dengue is the most prevalent mosquito-borne disease in Southeast Asia, where the incidence of systemic lupus erythematosus (SLE) is approximately 30 to 53 per 100,000. Severe dengue, however, is rarely reported among individuals with SLE. Here, whether sera of patients with SLE cross-neutralize dengue virus (DENV) was investigated. Serum samples were obtained from individuals with SLE who were dengue IgG and IgM serology negative. Neutralization assays were performed against the three major DENV serotypes. Of the dengue serology negative sera of individuals with SLE, 60%, 61% and 52% of the sera at 1/320 dilution showed more than 50% inhibition against dengue type-1 virus (DENV-1), DENV-2 and DENV-3, respectively. The neutralizing capacity of the sera was significantly greater against DENV-1 (P < 0.001) and DENV-3 (P < 0.01) than against DENV-2 (P < 0.05). Neutralization against the DENV correlated with dengue-specific IgG serum titers below the cut-off point for dengue positivity. Depletion of total IgG from the sera of patients with SLE resulted in significant decreases of up to 80% in DENV inhibition, suggesting that IgG plays an important role. However, some of the SLE sera was still able to neutralize DENV, even with IgG titers <0.1 OD absorbance. Our findings suggest that sera of patients with SLE contain IgG, and possibly other type of antibodies, that can cross-neutralize DENV, which may explain the rarity of severe dengue in individuals with SLE. Further studies, are needed to further substantiate this finding and to elucidate the specific neutralizing epitopes recognized by the sera of individuals with SLE.

Topics: Adult; Animals; Antibodies, Neutralizing; Antibodies, Viral; Chlorocebus aethiops; Cross Reactions; Dengue; Dengue Virus; Epitopes; Female; Humans; Immunity, Heterologous; Immunoglobulin G; Immunoglobulin M; Lupus Erythematosus, Systemic; Malaysia; Male; Middle Aged; Neutralization Tests; Serogroup; Vero Cells

Increased prevalence of dengue fever had led to increase stress in providing optimal care for patients. This has been identified as a potential factor that may lead to negative health effects on medical doctors. This study was designed to review the prevalence and associated factors of burnout syndrome (including depression, anxiety, and stress level) among clinicians in the setting of increasing cases of dengue in Malaysia.. A cross-sectional, multi-centre study was carried out among doctors in contact with patients with dengue infection from four major hospitals in Malaysia in 2015 using Maslach Burnout Inventory and DASS-21 questionnaire.. A total of 313 respondents were included in this study with 15.9% of the respondents experiencing high burnout syndrome. Long working hours, depression, anxiety, and stress were significantly associated with high degree of burnout syndrome (p<0.05). However, number of dengue cases reviewed was not significantly associated with the degree of burnout syndrome. Depression and stress were among factors identified as the predictors for burnout syndrome.. High degree of burnout syndrome among clinicians with significant correlations with symptoms of depression and stress will require early identification to enable early measures to resolve, as well as prevent it. Future studies with more hospitals involvement should be conducted to establish the relationship between the degree of burnout syndrome and prevalence of dengue infection.

Topics: Adult; Burnout, Professional; Cross-Sectional Studies; Dengue; Female; Health Personnel; Humans; Malaysia; Male; Prevalence; Risk Factors; Surveys and Questionnaires

Clinical Practice Guideline (CPG) provides evidence-based guidance for the management of Dengue Infection in adult patients. A cross sectional study was conducted to evaluate awareness and utilization of CPG among doctors in public or private hospitals and clinics in Malaysia. Doctors practicing only at hospital Medical and Emergency Departments were included, while private specialist clinics were excluded in this study. A multistage proportionate random sampling according to region (Central, Northern, Southern, Eastern, Sabah and Sarawak) was performed to select study participants. The overall response rate was 74% (84% for public hospitals, 82% for private hospitals, 70% for public clinics, and 64% for private clinics). The CPG Awareness and Utilization Feedback Form were used to determine the percentage in the study. The total numbers of respondent were 634 with response rate of 74%. The mean lengths of service of the respondent were 13.98 (11.55).A higher percentages of doctors from public facilities (99%) were aware of the CPG compared to those in private facilities (84%). The percentage of doctors utilising the CPG were also higher (98%) in public facilities compared to private facilities (86%). The percentage of Medical Officer in private facilities that utilizing the CPG were 84% compares to Medical Officer in public facilities 98%. The high percentage of doctors using the CPG in both public (97%) and private (94%) hospitals were also observed. However, only 69% of doctors in private clinics utilised the CPG compared to doctors in public clinics (98%). Doctors in both public and private facilities were aware of the dengue CPG. However, most doctors in private clinic were less likely to utilise the CPG. Therefore, there is a need to increase the level of CPG utilisation especially in private clinics.

Topics: Adult; Awareness; Dengue; Female; Humans; Malaysia; Male; Middle Aged; Practice Guidelines as Topic; Practice Patterns, Physicians'

Dengue is a fast spreading mosquito-borne disease that affects more than half of the population worldwide. An unprecedented outbreak happened in Guangzhou, China in 2014, which contributed 52 percent of all dengue cases that occurred in mainland China between 1990 and 2015. Our previous analysis, based on a deterministic model, concluded that the early timing of the first imported case that triggered local transmission and the excessive rainfall thereafter were the most important determinants of the large final epidemic size in 2014. However, the deterministic model did not allow us to explore the driving force of the early local transmission. Here, we expand the model to include stochastic elements and calculate the successful invasion rate of cases that entered Guangzhou at different times under different climate and intervention scenarios. The conclusion is that the higher number of imported cases in May and June was responsible for the early outbreak instead of climate. Although the excessive rainfall in 2014 did increase the success rate, this effect was offset by the low initial water level caused by interventions in late 2013. The success rate is strongly dependent on mosquito abundance during the recovery period of the imported case, since the first step of a successful invasion is infecting at least one local mosquito. The average final epidemic size of successful invasion decreases exponentially with introduction time, which means if an imported case in early summer initiates the infection process, the final number infected can be extremely large. Therefore, dengue outbreaks occurring in Thailand, Singapore, Malaysia and Vietnam in early summer merit greater attention, since the travel volumes between Guangzhou and these countries are large. As the climate changes, destroying mosquito breeding sites in Guangzhou can mitigate the detrimental effects of the probable increase in rainfall in spring and summer.

Topics: Animals; China; Climate; Climate Change; Culicidae; Dengue; Dengue Virus; Disease Outbreaks; Humans; Malaysia; Models, Theoretical; Seasons; Singapore; Thailand; Travel; Vietnam

Dengue and leptospirosis infections are currently two major endemics in Malaysia. Owing to the overlapping clinical symptoms between both the diseases, frequent misdiagnosis and confusion of treatment occurs. As a solution, the present work initiated a pilot study to investigate the incidence related to co-infection of leptospirosis among dengue patients. This enables the identification of more parameters to predict the occurrence of co-infection.. Two hundred sixty eight serum specimens collected from patients that were diagnosed for dengue fever were confirmed for dengue virus serotyping by real-time polymerase chain reaction. Clinical, laboratory and demographic data were extracted from the hospital database to identify patients with confirmed leptospirosis infection among the dengue patients. Thus, frequency of co-infection was calculated and association of the dataset with dengue-leptospirosis co-infection was statistically determined.. The frequency of dengue co-infection with leptospirosis was 4.1%. Male has higher preponderance of developing the co-infection and end result of shock as clinical symptom is more likely present among co-infected cases. It is also noteworthy that, DENV 1 is the common dengue serotype among all cases identified as dengue-leptospirosis co-infection in this study.. The increasing incidence of leptospirosis among dengue infected patients has posed the need to precisely identify the presence of co-infection for the betterment of treatment without mistakenly ruling out either one of them. Thus, anticipating the possible clinical symptoms and laboratory results of dengue-leptospirosis co-infection is essential.

Topics: Adult; Coinfection; Dengue; Dengue Virus; Female; Humans; Incidence; Leptospira; Leptospirosis; Malaysia; Male; Pilot Projects; Prevalence; Real-Time Polymerase Chain Reaction; Retrospective Studies; Serotyping; Young Adult

Dengue is hyperendemic in most of Southeast Asia. In this region, all four dengue virus serotypes are persistently present. Major dengue outbreak cycle occurs in a cyclical pattern involving the different dengue virus serotypes. In Malaysia, since the 1980s, the major outbreak cycles have involved dengue virus type 3 (DENV3), dengue virus type 1 (DENV1) and dengue virus type 2 (DENV2), occurring in that order (DENV3/DENV1/DENV2). Only limited information on the DENV3 cycles, however, have been described. In the current study, we examined the major outbreak cycle involving DENV3 using data from 1985 to 2016. We examined the genetic diversity of DENV3 isolates obtained during the period when DENV3 was the dominant serotype and during the inter-dominant transmission period. Results obtained suggest that the typical DENV3/DENV1/DENV2 cyclical outbreak cycle in Malaysia has recently been disrupted. The last recorded major outbreak cycle involving DENV3 occurred in 2002, and the expected major outbreak cycle involving DENV3 in 2006-2012 did not materialize. DENV genome analyses revealed that DENV3 genotype II (DENV3/II) was the predominant DENV3 genotype (67%-100%) recovered between 1987 and 2002. DENV3 genotype I (DENV3/I) emerged in 2002 followed by the introduction of DENV3 genotype III (DENV3/III) in 2008. These newly emerged DENV3 genotypes replaced DENV3/II, but there was no major upsurge of DENV3 cases that accompanied the emergence of these viruses. DENV3 remained in the background of DENV1 and DENV2 until now. Virus genome sequence analysis suggested that intrinsic differences within the different dengue virus genotypes could have influenced the transmission efficiency of DENV3. Further studies and continuous monitoring of the virus are needed for better understanding of the DENV transmission dynamics in hyperendemic regions.

Topics: Dengue; Dengue Virus; Disease Outbreaks; Genetic Variation; Genome, Viral; Genotype; Humans; Malaysia; Phylogeny

Mosquito-borne dengue virus (DENV) is maintained in a sylvatic, enzootic cycle of transmission between canopy-dwelling non-human primates and Aedes mosquitoes in Borneo. Sylvatic DENV can spill over into humans living in proximity to forest foci of transmission, in some cases resulting in severe dengue disease. The most likely vectors of such spillover (bridge vectors) in Borneo are Ae. albopictus and Ae. niveus. Borneo is currently experiencing extensive forest clearance. To gauge the effect of this change in forest cover on the likelihood of sylvatic DENV spillover, it is first necessary to characterize the distribution of bridge vectors in different land cover types. In the current study, we hypothesized that Ae. niveus and Ae. albopictus would show significantly different distributions in different land cover types; specifically, we predicted that Ae. niveus would be most abundant in forests whereas Ae. albopictus would have a more even distribution in the landscape.. Mosquitoes were collected from a total of 15 sites using gravid traps and a backpack aspirator around Kampong Puruh Karu, Sarawak, Malaysian Borneo, where sylvatic DENV spillover has been documented. A total of 2447 mosquitoes comprising 10 genera and 4 species of Aedes, were collected over the three years, 2013, 2014 and 2016, in the three major land cover types in the area, homestead, agriculture and forest. Mosquitoes were identified morphologically, pooled by species and gender, homogenized, and subject to DNA barcoding of each Aedes species and to arbovirus screening. As predicted, Ae. niveus was found almost exclusively in forests whereas Ae. albopictus was collected in all land cover types. Aedes albopictus was significantly (P = 0.04) more abundant in agricultural fields than forests. Sylvatic DENV was not detected in any Aedes mosquito pools, however genomes of 14 viruses were detected using next generation sequencing.. Land cover type affects the abundance and distribution of the most likely bridge vectors of sylvatic DENV in Malaysia Borneo. Conversion of forests to agriculture will likely decrease the range and abundance of Ae. niveus but enhance the abundance of Ae. albopictus.

Topics: Aedes; Animal Distribution; Animals; Borneo; Dengue; Dengue Virus; Forests; High-Throughput Nucleotide Sequencing; Humans; Insect Vectors; Larva; Malaysia; Primates; Severe Dengue

The global expansion of Ae. albopictus from its native range in Southeast Asia has been implicated in the recent emergence of dengue endemicity in Malaysia. Genetic variability studies of Ae. albopictus are currently lacking in the Malaysian setting, yet are crucial to enhancing the existing vector control strategies. The study was conducted to establish the genetic variability of maternally inherited mitochondrial DNA encoding for cytochrome oxidase subunit 1 (CO1) gene in Ae. albopictus. Twelve localities were selected in the Subang Jaya district based on temporal indices utilizing 120 mosquito samples. Genetic polymorphism and phylogenetic analysis were conducted to unveil the genetic variability and geographic origins of Ae. albopictus. The haplotype network was mapped to determine the genealogical relationship of sequences among groups of population in the Asian region. Comparison of Malaysian CO1 sequences with sequences derived from five Asian countries revealed genetically distinct Ae. albopictus populations. Phylogenetic analysis revealed that all sequences from other Asian countries descended from the same genetic lineage as the Malaysian sequences. Noteworthy, our study highlights the discovery of 20 novel haplotypes within the Malaysian population which to date had not been reported. These findings could help determine the genetic variation of this invasive species, which in turn could possibly improve the current dengue vector surveillance strategies, locally and regionally.

Topics: Aedes; Animals; Dengue; Electron Transport Complex IV; Genetic Variation; Haplotypes; Malaysia; Mosquito Vectors; Phylogeny; Phylogeography

Behavioural impact programmes are especially effective for dengue control and prevention. Universities are key settings for health promotion, so understanding factors that influence the practice of dengue prevention within a university community becomes important. This study aimed to examine the factors affecting dengue knowledge, attitude and preventive practices amongst students and staff of a public university. A cross-sectional survey study was conducted in Kuala Lumpur, Malaysia. A total of 372 students and staff of the NDUM were recruited by stratified sampling method. Data were collected via self-administered pre-tested structured questionnaires covering socio-demography and dengue KAP. Data were analysed descriptively. For bivariate analysis, Chi square test was applied. To explore the factors independently associated with the practice of dengue prevention, a logistic regression model was introduced. Overall, the participants had moderate dengue-related knowledge, good attitudes and good preventive practices. The majority had misconceptions about mosquito biting habits (83.8 %), seasonality of dengue epidemics (73.2 %), and mosquito breeding sites (70.3 %). Staff were more likely to have good dengue-related knowledge (p < 0.001) and attitudes (p = 0.008) than students. There was statistically significant positive association between the level of dengue knowledge and monthly average household income (p = 0.008), age (p < 0.001) and education (p < 0.001). Having good attitudes towards dengue was associated with being a non-Malay (p = 0.034), having higher monthly average household income (p = 0.047) and tertiary education (p < 0.001). In regression analysis, only dengue knowledge and dengue attitudes were significantly and positively associated with practice of dengue prevention. Dengue preventive strategies amongst university students and staff should focus on maintaining good dengue-related preventive practices. Educational campaigns should mainly target students, young staff members, and those with lower level of education and income.

Topics: Adolescent; Adult; Cross-Sectional Studies; Dengue; Faculty; Female; Health Knowledge, Attitudes, Practice; Humans; Malaysia; Male; Middle Aged; Students; Surveys and Questionnaires; Universities; Young Adult

Dengue and malaria are two common, mosquito-borne infections, which may lead to mortality if not managed properly. Concurrent infections of dengue and malaria are rare due to the different habitats of its vectors and activities of different carrier mosquitoes. The first case reported was in 2005. Since then, several concurrent infections have been reported between the dengue virus (DENV) and the malaria protozoans, Plasmodium falciparum and Plasmodium vivax. Symptoms of each infection may be masked by a simultaneous second infection, resulting in late treatment and severe complications. Plasmodium knowlesi is also a common cause of malaria in Malaysia with one of the highest rates of mortality. This report is one of the earliest in literature of concomitant infection between DENV and P. knowlesi in which a delay in diagnosis had placed a patient in a life-threatening situation.. A 59-year old man staying near the Belum-Temengor rainforest at the Malaysia-Thailand border was admitted with fever for 6 days, with respiratory distress. His non-structural protein 1 antigen and Anti-DENV Immunoglobulin M tests were positive. He was treated for severe dengue with compensated shock. Treating the dengue had so distracted the clinicians that a blood film for the malaria parasite was not done. Despite aggressive supportive treatment in the intensive care unit (ICU), the patient had unresolved acidosis as well as multi-organ failure involving respiratory, renal, liver, and haematological systems. It was due to the presentation of shivering in the ICU, that a blood film was done on the second day that revealed the presence of P. knowlesi with a parasite count of 520,000/μL. The patient was subsequently treated with artesunate-doxycycline and made a good recovery after nine days in ICU.. This case contributes to the body of literature on co-infection between DENV and P. knowlesi and highlights the clinical consequences, which can be severe. Awareness should be raised among health-care workers on the possibility of dengue-malaria co-infection in this region. Further research is required to determine the real incidence and risk of co-infection in order to improve the management of acute febrile illness.

Topics: Antimalarials; Artemisinins; Artesunate; Coinfection; Dengue; Dengue Virus; Doxycycline; Humans; Malaria; Malaysia; Male; Middle Aged; Plasmodium knowlesi; Thailand; Treatment Outcome

Dengue control and prevention rely heavily on insecticide-based interventions. However, insecticide resistance in the dengue vector Aedes aegypti, threatens the continued effectiveness of these tools. The molecular basis of the resistance remains uncharacterised in many endemic countries including Malaysia, preventing the design of evidence-based resistance management. Here, we investigated the underlying molecular basis of multiple insecticide resistance in Ae. aegypti populations across Malaysia detecting the major genes driving the metabolic resistance.. Genome-wide microarray-based transcription analysis was carried out to detect the genes associated with metabolic resistance in these populations. Comparisons of the susceptible New Orleans strain to three non-exposed multiple insecticide resistant field strains; Penang, Kuala Lumpur and Kota Bharu detected 2605, 1480 and 425 differentially expressed transcripts respectively (fold-change>2 and p-value ≤ 0.05). 204 genes were commonly over-expressed with monooxygenase P450 genes (CYP9J27, CYP6CB1, CYP9J26 and CYP9M4) consistently the most up-regulated detoxification genes in all populations, indicating that they possibly play an important role in the resistance. In addition, glutathione S-transferases, carboxylesterases and other gene families commonly associated with insecticide resistance were also over-expressed. Gene Ontology (GO) enrichment analysis indicated an over-representation of GO terms linked to resistance such as monooxygenases, carboxylesterases, glutathione S-transferases and heme-binding. Polymorphism analysis of CYP9J27 sequences revealed a high level of polymorphism (except in Joho Bharu), suggesting a limited directional selection on this gene. In silico analysis of CYP9J27 activity through modelling and docking simulations suggested that this gene is involved in the multiple resistance in Malaysian populations as it is predicted to metabolise pyrethroids, DDT and bendiocarb.. The predominant over-expression of cytochrome P450s suggests that synergist-based (PBO) control tools could be utilised to improve control of this major dengue vector across Malaysia.

Topics: Aedes; Animals; Cytochrome P-450 Enzyme System; Dengue; Female; Insect Proteins; Insect Vectors; Insecticide Resistance; Insecticides; Malaysia; Polymorphism, Genetic; Pyrethrins

Dengue disease poses a great economic burden in Malaysia.. This study evaluated the cost effectiveness and impact of dengue vaccination in Malaysia from both provider and societal perspectives using a dynamic transmission mathematical model. The model incorporated sensitivity analyses, Malaysia-specific data, evidence from recent phase III studies and pooled efficacy and long-term safety data to refine the estimates from previous published studies. Unit costs were valued in $US, year 2013 values.. Six vaccination programmes employing a three-dose schedule were identified as the most likely programmes to be implemented. In all programmes, vaccination produced positive benefits expressed as reductions in dengue cases, dengue-related deaths, life-years lost, disability-adjusted life-years and dengue treatment costs. Instead of incremental cost-effectiveness ratios (ICERs), we evaluated the cost effectiveness of the programmes by calculating the threshold prices for a highly cost-effective strategy [ICER <1 × gross domestic product (GDP) per capita] and a cost-effective strategy (ICER between 1 and 3 × GDP per capita). We found that vaccination may be cost effective up to a price of $US32.39 for programme 6 (highly cost effective up to $US14.15) and up to a price of $US100.59 for programme 1 (highly cost effective up to $US47.96) from the provider perspective. The cost-effectiveness analysis is sensitive to under-reporting, vaccine protection duration and model time horizon.. Routine vaccination for a population aged 13 years with a catch-up cohort aged 14-30 years in targeted hotspot areas appears to be the best-value strategy among those investigated. Dengue vaccination is a potentially good investment if the purchaser can negotiate a price at or below the cost-effective threshold price.

Topics: Adolescent; Adult; Cost of Illness; Cost-Benefit Analysis; Dengue; Dengue Vaccines; Health Care Costs; Humans; Immunization Programs; Malaysia; Models, Theoretical; Vaccination; Young Adult

The aims of this study were to explore the differences in (1) the perception of severity towards ZIKV infection and dengue fever, and (2) mosquito control practices before and after the ZIKV outbreak were declared a Public Health Emergency of International Concern (PHEIC). Data were collected between Feb to May 2016 using a computer-assisted telephone interviewing system. The median scale score for perceived severity of ZIKV was 3 (interquartile range [IQR] 1-5) versus 4 (IQR 3-5) for dengue (P < 0.001). The scores for mosquito control practices before and after ZIKV was declared a PHEIC were similar, at 4 (IQR 3-5). Multivariate analysis revealed that participants with a higher score for perception of severity of ZIKV were more likely to report greater mosquito control practices after the declaration of the PHEIC (OR 1.822 [95% CI 1.107-2.998]). The emerging ZIKV pandemic requires concerted efforts to enhance mosquito control practices among the Malaysian public. Efforts to improve public mosquito control practices should focus on enhancing the perception of the severity of ZIKV.

Topics: Adolescent; Adult; Cross-Sectional Studies; Dengue; Female; Health Knowledge, Attitudes, Practice; Humans; Malaysia; Male; Middle Aged; Mosquito Control; Young Adult; Zika Virus Infection

Haemophagocytic lymphohistiocytosis (HLH) is a potentially fatal disorder resulting from uncontrolled hyperinflammatory response. There had been increase in cases of one of the secondary form of HLH, i.e., infectionassociated haemophagocytic syndrome (IAHS) in severe dengue in recent years. However, the condition remains under diagnosed due to lack of awareness compounded by the lack of validated diagnostic criteria. Severe hepatitis with prolonged cytopenias, severe hyperferritinemia, hypofibrinogenemia and persistent fever were evident in all four cases reported. All the subjects survived with supportive care and adjuvant steroid therapy. Prospective controlled studies are needed to develop diagnostic criteria and management protocol for IAHS in severe dengue.

Topics: Adolescent; Adult; Child; Dengue; Female; Hospitals, District; Humans; Lymphohistiocytosis, Hemophagocytic; Malaysia; Male; Middle Aged

Dengue is endemic in all parts of Malaysia. However, there is limited\ data regarding the cost burden of this disease at household level. We aimed to\ examine the cost of dengue infection at the household level in Seremban District,\ Malaysia. This cost assessment can provide an insight to policy-makers about\ economic impact of dengue infection in order to guide and prioritize control strategies.\ The data were collected via interview. We evaluated120 previous dengue\ infection patients registered at the Tuanku Ja’afar Hospital, Seremban District,\ Malaysia. The average duration of dengue illness was 9.69 days. The average\ household days lost was 18.7; students lost an average of 6.3 days of school and\ patients and caregivers lost an average of 12.5 days of work. The mean total cost\ per case of dengue infection was estimated to be USD365.16 with the indirect\ cost being USD327.90 (89.8% of the total cost) and the direct cost being USD37.26\ (10.2% of the total cost). Our findings suggest each episode of dengue infection\ imposes a significant financial burden at the household level in Seremban District,\ Malaysia; most of the burden being indirect cost. This cost needs to be factored\ into the overall cost to society of dengue infection. This data can inform policy\ makers when allocating resources to manage public health problems in Malaysia.

Topics: Cost of Illness; Cross-Sectional Studies; Dengue; Female; Hospitalization; Humans; Interviews as Topic; Malaysia; Male; Office Visits; Sick Leave; Transportation

Several criteria have been used to stratify acute kidney injury (AKI) in dengue infection and have resulted in variations in its incidence as well as clinic-laboratory characteristics. The current study was aimed to compare three commonly used criteria of AKI among patients with dengue.. 667 patients with dengue were defined and staged according to the conventional definition (CD), the Acute Kidney Injury Network (AKIN) and the Risk, Injury, Failure, Loss of function, End stage renal disease (RIFLE) criteria. Appropriate statistical methods were used to compare these three criteria.. The incidence of AKI during dengue infection was 14.2% by AKIN criteria, 12.6% by RIFLE criteria and 4.2% by CD. AKIN and RIFLE criteria were comparable while AKIN-I identified 11 more patients with AKI than RIFLE-R (76.8% vs. 73.8%, p=0.023). CD was found to be less sensitive than AKIN and RIFLE due to stratification of only severe AKI cases with serum creatinine ≥176.8 µmol/L. Overall mortality was 1.2% and severe stages of AKI were associated with increased mortality (p<0.001). AKIN criteria identified seven risk factors, RIFLE identified six and CD identified three risk factors. Old age, severe dengue and the use of nephrotoxic drugs were found to be independent predictors identified by all criteria while hypertension was only identified by AKIN.. The incidence of AKI in dengue infection, the risk factors for its development and clinico-laboratory characteristics vary significantly according to the diagnostic criteria used. In our analysis, AKIN and RIFLE were comparable to each other and superior to CD with regard to early diagnosis and sensitivity.

Topics: Acute Kidney Injury; Adult; Age Factors; Antiviral Agents; Biomarkers; Chemical and Drug Induced Liver Injury; Dengue; Female; Glomerular Filtration Rate; Hospital Mortality; Humans; Incidence; Malaysia; Male; Practice Guidelines as Topic; Predictive Value of Tests; Prognosis; Retrospective Studies; Severity of Illness Index; Viral Vaccines

In Malaysia, the number of reported cases of dengue fever demonstrates an increasing trend. Since dengue fever has no vaccine or antiviral treatment available, it has become a burden. Complementary and alternative medicine (CAM) has become one of the good alternatives to treat the patients with dengue fever. There is limited study on the use of CAM among patients with dengue fever, particularly in hospital settings. This study aims to determine the prevalence, types, reasons, expenditure, and resource of information on CAM use among patients with dengue fever.. This is a descriptive, cross-sectional study of 306 patients with dengue fever, which was carried out at the dengue clinic of three hospitals. Data were analysed using IBM SPSS Statistics version 21.0 and logistic regression analysis was used to determine the factors associated with CAM use.. The prevalence of CAM use was 85.3% among patients with dengue fever. The most popular CAMs were isotonic drinks (85.8%), crab soup (46.7%) and papaya leaf extract (22.2%). The most common reason for CAM use was a good impression of CAM from other CAM users (33.3%). The main resource of information on CAM use among patients with dengue fever was family (54.8%). In multiple logistic regression analysis, dengue fever patients with a tertiary level are more likely to use CAM 5.8 (95% confidence interval (CI 1.62-20.45) and 3.8 (95% CI 1.12-12.93) times than secondary level and primary and below respectively.. CAM was commonly used by patients with dengue fever. The predictor of CAM use was a higher level of education.

Topics: Adult; Attitude to Health; Complementary Therapies; Cross-Sectional Studies; Dengue; Female; Hospitals; Humans; Malaysia; Male; Young Adult

Dengue fever (DF) is an urban vector-borne disease transmitted by Aedes aegypti and Aedes albopictus. Both species deposit their eggs in favorable breeding sites either in natural or artificial containers. An understanding of their habitat characteristics is crucial in curbing DF outbreaks. A search and destroy survey was carried out at 10 dengue hotspot localities in Shah Alam, Malaysia. A quantitative in-situ measurement of selected physical parameters was conducted focusing on the environmental characteristics and the presence of vegetation. Larvae and pupae found in different types of container were morphologically identified.. Evidence of breeding was discovered in 62 containers. Rubber materials (container efficiency: 2.10), with clear water in the presence of dead vegetation (71 and 33% respectively) were found to be most efficient for pupae development. Furthermore, low water volume (60%) was preferred for breeding purposes. Kruskal-Wallis test demonstrated that water volume, wind velocity and distance from habitation were statistically significant towards dengue vectors.. Our findings have provided the profile of Aedes species based on environmental and water conditions in hotspot areas in Malaysia. These outcomes provide useful information regarding container characteristics that can enable selective elimination of vector habitat thus minimizing the risk of dengue outbreak.

Topics: Aedes; Animals; Dengue; Ecosystem; Humans; Larva; Malaysia; Mosquito Vectors; Plants; Pupa; Reproduction; Rubber; Species Specificity; Urban Health; Water

Control of Aedes albopictus, major dengue and chikungunya vector, is threatened by growing cases of insecticide resistance. The mechanisms driving this resistance remain poorly characterised. This study investigated the molecular basis of insecticide resistance in Malaysian populations of Ae. albopictus. Microarray-based transcription profiling revealed that metabolic resistance (cytochrome P450 up-regulation) and possibly a reduced penetration mechanism (consistent over-expression of cuticular protein genes) were associated with pyrethroid resistance. CYP6P12 over-expression was strongly associated with pyrethroid resistance whereas CYP6N3 was rather consistently over-expressed across carbamate and DDT resistant populations. Other detoxification genes also up-regulated in permethrin resistant mosquitoes included a glucuronosyltransferase (AAEL014279-RA) and the glutathione-S transferases GSTS1 and GSTT3. Functional analyses further supported that CYP6P12 contributes to pyrethroid resistance in Ae. albopictus as transgenic expression of CYP6P12 in Drosophila was sufficient to confer pyrethroid resistance in these flies. Furthermore, molecular docking simulations predicted CYP6P12 possessing enzymatic activity towards pyrethroids. Patterns of polymorphism suggested early sign of selection acting on CYP6P12 but not on CYP6N3. The major role played by P450 in the absence of kdr mutations suggests that addition of the synergist PBO to pyrethroids could improve the efficacy of this insecticide class and overcome resistance in field populations of Ae. albopictus.

Topics: Aedes; Animals; Animals, Genetically Modified; Cytochrome P450 Family 6; Dengue; Gene Expression Profiling; Gene Expression Regulation; Gene Knockdown Techniques; Genetics, Population; Insecticide Resistance; Insecticides; Malaysia; Models, Molecular; Molecular Conformation; Polymorphism, Genetic; Protein Binding; Pyrethrins; Reproducibility of Results

The increasing incidence and geographical distribution of dengue has had significant impact on global healthcare services and resources. This study aimed to determine the factors associated with dengue-related mortality in a cohort of Malaysian patients.. This was a retrospective cohort study of patients in the Malaysian National Dengue Registry of 2013. The outcome measure was dengue-related mortality. Associations between sociodemographic and clinical variables with the outcome were analysed using multivariate analysis.. There were 43 347 cases of which 13081 were serologically confirmed. The mean age was 30.0 years (SD 15.7); 60.2% were male. The incidence of dengue increased towards the later part of the calendar year. There were 92 probable dengue mortalities, of which 41 were serologically confirmed. Multivariate analysis in those with positive serology showed that increasing age (OR 1.03; CI:1.01-1.05), persistent vomiting (OR 13.34; CI: 1.92-92.95), bleeding (OR 5.84; CI 2.17-15.70) and severe plasma leakage (OR 66.68; CI: 9.13-487.23) were associated with mortality. Factors associated with probable dengue mortality were increasing age (OR 1.04; CI:1.03-1.06), female gender (OR 1.53; CI:1.01-2.33), nausea and/or vomiting (OR 1.80; CI:1.17-2.77), bleeding (OR 3.01; CI:1.29-7.04), lethargy and/or restlessness (OR 5.97; CI:2.26-15.78), severe plasma leakage (OR 14.72; CI:1.54-140.70), and shock (OR 1805.37; CI:125.44-25982.98), in the overall study population.. Older persons and those with persistent vomiting, bleeding or severe plasma leakage, which were associated with mortality, at notification should be monitored closely and referred early if indicated. Doctors and primary care practitioners need to detect patients with dengue early before they develop these severe signs and symptoms.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Child; Child, Preschool; Cohort Studies; Dengue; Female; Humans; Incidence; Infant; Malaysia; Male; Middle Aged; Registries; Retrospective Studies; Risk Factors; Young Adult

Globally, dengue infections constitute a significant public health burden. In recent decades, Malaysia has become a dengue hyper-endemic country with the co-circulation of the four dengue virus serotypes. The cyclical dominance of sub-types contributes to a pattern of major outbreaks. The consequences can be observed in the rising incidence of reported dengue cases and dengue related deaths. Understanding the complex interaction of the dengue virus, its human hosts and the mosquito vectors at the community level may help develop strategies for addressing the problem.. A prospective cohort study will be conducted in Segamat district of Johor State in Peninsular Malaysia. Researchers received approval from the Malaysian Medical Research Ethics Committee and Monash University Human Research Ethics Committee. The study will be conducted at a Malaysian based health and demographic surveillance site over a 1 year period in three different settings (urban, semi-urban and rural). The study will recruit healthy adults (male and female) aged 18 years and over, from three ethnic groups (Malay, Chinese and Indian). The sample size calculated using the Fleiss method with continuity correction is 333. Sero-surveillance of participants will be undertaken to identify asymptomatic, otherwise healthy cases; cases with dengue fever who are managed as out-patients; and cases with dengue fever admitted to a hospital. A genetic analysis of the participants will be undertaken to determine whether there is a relationship between genetic predisposition and disease severity. A detailed medical history, past history of dengue infection, vaccination history against other flaviviruses such as Japanese encephalitis and Yellow fever, and the family history of dengue infection will also be collected. In addition, a mosquito surveillance will be carried out simultaneously in recruitment areas to determine the molecular taxonomy of circulating vectors.. The research findings will estimate the burden of asymptomatic and symptomatic dengue at the community level. It will also examine the relationship between virus serotypes and host genotypes, and the association of the clinical manifestation of the early phase with the entire course of illness.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Cohort Studies; Dengue; Dengue Virus; Ethnicity; Female; Humans; Malaysia; Male; Middle Aged; Prospective Studies; Residence Characteristics; Young Adult

As there is no specific treatment for dengue, early detection and access to proper treatment may lower dengue fatality. Therefore, having new techniques for the early detection of dengue fever, such as the use of dengue test kit, is vitally important. The aims of the study were: 1) identify factors associated with acceptance of a home self-test kit for dengue fever if the dengue test is available to the public and 2) find out the characteristics of the test kits that influence the use of the dengue test kit.. A national telephone survey was carried out with 2,512 individuals of the Malaysian public aged 18-60 years old. Individuals were contacted by random digit dialling covering the whole of Malaysia from February 2012 to June 2013.. From 2,512 participants, 6.1 % reported to have heard of the availability of the dengue home test kit and of these, 44.8 % expressed their intention to use the test kit if it was available. Multivariate logistic regressions indicated that participants with primary (OR: 0.65; 95 % CI: 0.43-0.89; p = 0.02, vs. tertiary educational level) and secondary educational levels (OR: 0.73; 95 % CI: 0.57-0.90; p = 0.01, vs. tertiary educational level) were less likely than participants with a tertiary educational level to use a home self-testing dengue kit for dengue if the kit was available. Participants with lower perceived barriers to dengue prevention (level of barriers 0-5) were less likely (OR: 0.67, 95 % CI: 0.53-0.85, p < 0.001, vs. higher perceived barriers) to use a home self-testing dengue kit for dengue if the kit was available compared to those with higher perceived barriers to dengue prevention (level of barriers 6-10). Participants with a lower total dengue fever knowledge score (range 0-22) were also less likely to use a home self-testing dengue kit for dengue if the kit was available (OR: 0.75; 95 % CI: 0.61-0.91, p = 0.001, vs. higher total dengue fever knowledge score) compared to those with a higher total dengue fever knowledge score (range 23-44). With response to characteristics of the test kit, participants indicated that ease of usability and easy to understand instructions were the most important factors influencing the decision to use the dengue home test kit; this was followed by the price of the test kit.. The study highlights the need for provision of information to increase knowledge about the home self-testing dengue kit. Educational interventions should target people with low educational levels, those with lower dengue fever knowledge and those with lower perceived barriers to dengue prevention.

Topics: Adolescent; Adult; Awareness; Communicable Diseases; Costs and Cost Analysis; Cross-Sectional Studies; Dengue; Educational Status; Female; Health Knowledge, Attitudes, Practice; Humans; Intention; Logistic Models; Malaysia; Male; Mass Screening; Middle Aged; Odds Ratio; Patient Acceptance of Health Care; Self Care; Surveys and Questionnaires; Young Adult

Each year an estimated 390 million dengue infections occur worldwide. In Malaysia, dengue is a growing public health concern but estimate of its disease burden remains uncertain. We compared the urban-rural difference of dengue seroprevalence and determined age-specific dengue seroprevalence in Malaysia.. We undertook analysis on 11,821 subjects from six seroprevalence surveys conducted in Malaysia between 2001 and 2013, which composed of five urban and two rural series.. Prevalence of dengue increased with age in both urban and rural locations in Malaysia, which exceeded 90 % among those aged 70 years or beyond. The age-specific rates of the 5 urban surveys overlapped without clear separation among them, while prevalence was lower in younger subjects in rural series than in urban series, the trend reversed in older subjects. There were no differences in the seroprevalence by gender, ethnicity or region. Poisson regression model confirmed the prevalence have not changed in urban areas since 2001 but in rural areas, there was a significant positive time trend such that by year 2008, rural prevalence was as high as in urban areas.. Dengue seroprevalence has stabilized but persisted at a high level in urban areas since 2001, and is fast stabilizing in rural areas at the same high urban levels by 2008. The cumulative seroprevalence of dengue exceeds 90 % by the age of 70 years, which translates into 16.5 million people or 55 % of the total population in Malaysia, being infected by dengue by 2013.

Topics: Adolescent; Adult; Age Distribution; Aged; Aged, 80 and over; Child; Child, Preschool; Dengue; Female; Humans; Infant; Malaysia; Male; Middle Aged; Poisson Distribution; Prevalence; Regression Analysis; Rural Population; Seroepidemiologic Studies; Urban Population; Young Adult

Perceptions about illnesses may influence self-care and preventive health behaviours. Illness perceptions of the Zika virus (ZIKV) infection were investigated under the framework of the Self-Regulation Model of Illness. Illness perception differences between ZIKV and dengue fever were also examined. Lastly, associations between illness perceptions of ZIKV with mosquito prevention practices were studied. Samples were drawn from landline telephone numbers using computer-assisted telephone interviewing in Malaysia. A total of 567 respondents completed the survey between February 2015 and May 2016. The median and interquartile range (IQR) for the total six dimensions of illness perceptions score was higher for dengue (23.0 (IQR 17.0-28.0)) than ZIKV (20.0 (IRQ 11.0-28.0)),

Topics: Adolescent; Adult; Animals; Dengue; Female; Health Knowledge, Attitudes, Practice; Humans; Malaysia; Male; Middle Aged; Mosquito Control; Young Adult; Zika Virus Infection

Dengue fever is a debilitating and infectious disease that could be life-threatening. It is caused by the dengue virus which affects millions of people in the tropical area. Currently, there is no cure for the disease as there is no vaccine available. Thus, prevention of the vector population using conventional methods is by far the main strategy but has been found ineffective. A genetically modified (GM) mosquito is among the favoured alternatives to curb dengue fever in Malaysia. Past studies have shown that development and diffusion of gene technology products depends heavily upon public acceptance. The purpose of this study is to identify the relevant factors influencing stakeholders' attitudes toward the GM Aedes mosquito and to analyse the relationships between all the factors using the structural equation model. A survey was carried out on 509 respondents from various stakeholder groups in the Klang Valley region of Malaysia. Results of the survey have confirmed that public perception towards complex issues such as gene technology should be seen as a multi-faceted process. The perceived benefit-perceived risk balance is very important in determining the most predominant predictor of attitudes toward a GM mosquito. In this study the stakeholders perceived the benefit of the GM mosquito as outweighing its risk, translating perceived benefit as the most important direct predictor of attitudes toward the GM mosquito. Trust in key players has a direct influence on attitudes toward the GM mosquito while moral concern exhibited an indirect influence through perceived benefits. Other factors such as attitudes toward technology and nature were also indirect predictors of attitudes toward the GM mosquito while religiosity and engagement did not exhibited any significant roles. The research findings serve as a useful database to understand public acceptance and the social construct of public attitudes towards the GM mosquito to combat dengue.

Topics: Adolescent; Adult; Aedes; Animals; Attitude; Dengue; Humans; Malaysia; Morals; Organisms, Genetically Modified; Public Opinion; Risk; Surveys and Questionnaires; Trust

This qualitative study aimed to describe field worker perceptions, evaluations of worth, and time costs of routine dengue vector surveillance methods in Cairns (Australia), Kuala Lumpur and Petaling District (Malaysia). In Cairns, the BG-Sentinel trap is a favored method for field workers because of its user-friendliness, but is not as cost-efficient as the sticky ovitrap. In Kuala Lumpur, the Mosquito Larvae Trapping Device is perceived as a solution for the inaccessibility of premises to larval surveys. Nonetheless, the larval survey method is retained in Malaysia for prompt detection of dengue vectors. For dengue vector surveillance to be successful, there needs to be not only technical, quantitative evaluations of method performance but also an appreciation of how amenable field workers are to using particular methods. Here, we report novel field worker perceptions of dengue vector surveillance methods in addition to time analysis for each method.

Topics: Aedes; Animals; Australia; Dengue; Health Personnel; Humans; Insect Vectors; Malaysia; Population Surveillance; Qualitative Research

To assess the impact of past dengue epidemics in Singapore, we undertook a national seroepidemiological study to determine the prevalence of past dengue virus (DENV) infection in the adult population in 2010 and make comparisons with the seroprevalence in 2004. The study involved residual sera from 3293 adults aged 18-79 years who participated in a national health survey in 2010. The overall prevalence of anti-DENV IgG antibodies was 56·8% (95% confidence interval 55·1-58·5) in 2010. The seroprevalence increased significantly with age. Males had significantly higher seroprevalence than females (61·5% vs. 53·2%). Among the three major ethnic groups, Malays had the lowest seroprevalence (50·2%) compared to Chinese (57·0%) and Indians (62·0%). The age-standardized seroprevalence in adults was significantly lower in 2010 (54·4%) compared to 2004 (63·1%). Older age, male gender, Indian ethnicity, permanent residency and being home-bound were independent risk factors significantly associated with seropositivity. About 43% of the Singapore adult resident population remain susceptible to DENV infection as a result of the successful implementation of a comprehensive nationwide Aedes surveillance and control programme since the 1970s. Vector suppression and concerted efforts of all stakeholders in the community remain the key strategy in the prevention and control of dengue.

Topics: Adolescent; Adult; Aged; China; Dengue; Female; Humans; India; Malaysia; Male; Middle Aged; Seroepidemiologic Studies; Singapore; Young Adult

We aimed to reparameterize and validate an existing dengue model, comprising an entomological component (CIMSiM) and a disease component (DENSiM) for application in Malaysia. With the model we aimed to measure the effect of importation rate on dengue incidence, and to determine the potential impact of moderate climate change (a 1 °C temperature increase) on dengue activity. Dengue models (comprising CIMSiM and DENSiM) were reparameterized for a simulated Malaysian village of 10 000 people, and validated against monthly dengue case data from the district of Petaling Jaya in the state of Selangor. Simulations were also performed for 2008-2012 for variable virus importation rates (ranging from 1 to 25 per week) and dengue incidence determined. Dengue incidence in the period 2010-2012 was modelled, twice, with observed daily weather and with a 1 °C increase, the latter to simulate moderate climate change. Strong concordance between simulated and observed monthly dengue cases was observed (up to r = 0·72). There was a linear relationship between importation and incidence. However, a doubling of dengue importation did not equate to a doubling of dengue activity. The largest individual dengue outbreak was observed with the lowest dengue importation rate. Moderate climate change resulted in an overall decrease in dengue activity over a 3-year period, linked to high human seroprevalence early on in the simulation. Our results suggest that moderate reductions in importation with control programmes may not reduce the frequency of large outbreaks. Moderate increases in temperature do not necessarily lead to greater dengue incidence.

Topics: Aedes; Animals; Climate Change; Dengue; Entomology; Humans; Malaysia; Models, Theoretical; Software

Evaluation of binding between analytes and its relevant ligands on surface plasmon resonance (SPR) biosensor is of considerable importance for accurate determination and screening of an interference in immunosensors. Dengue virus serotype 2 was used as a case study in this investigation. This research work compares and interprets the results obtained from analytical analysis with the experimental ones. Both the theoretical calculations and experimental results are verified with one sample from each category of dengue serotypes 2 (low, mid, and high positive), which have been examined in the database of established laboratorial diagnosis. In order to perform this investigation, the SPR angle variations are calculated, analyzed, and then validated via experimental SPR angle variations. Accordingly, the error ratios of 5.35, 6.54, and 3.72% were obtained for the low-, mid-, and high-positive-specific immune globulins of patient serums, respectively. In addition, the magnetic fields of the biosensor are numerically simulated to show the effect of different binding mediums.

Topics: Antibodies, Viral; Dengue; Dengue Virus; Humans; Immunoglobulin M; Malaysia; Reagent Kits, Diagnostic; Surface Plasmon Resonance

Entomological surveillance was conducted in order to determine the abundance and to evaluate any changes of biological vectors or ecology, especially in the dengue outbreak areas. The abundance and breeding preference of Aedes albopictus and Aedes aegypti were conducted in selected dengue outbreak localities in three states of peninsular Malaysia namely Selangor, Federal Territory of Kuala Lumpur, and Penang Island using ovitraps and larval survey method. It was determined that Ae. albopictus was predominant in most of the localities and found to breed more outdoor than indoor. A wide range of breeding foci were recorded in this study. It was also determined that ovitrap method was more effective to detect the presence of Aedes mosquitoes when the larval survey was at low rate of infestation. The abundance of Ae. albopictus in dengue outbreak localities emphasis that the vector control programme should also target this species together with the primary dengue vector, Ae. aegypti.

Topics: Aedes; Animals; Dengue; Disease Outbreaks; Entomology; Female; Malaysia; Sexual Behavior, Animal

Dengue serotype surveillance is important as any changes in serotype distribution may result in an outbreak or increase in severe dengue cases. This study aimed to determine circulating dengue serotypes in two hospitals in Selangor. Serum samples were collected from patients admitted for dengue at these two major public hospitals i.e. Hospital Sungai Buloh (HSB) and Hospital Tunku Ampuan Rahimah (HTAR) between November 2010 and August 2011 and subjected to real-time RT-PCR using SYBR® Green. All four dengue serotypes were detected in samples from both hospitals. The predominating serotype was dengue 1 in samples from both hospitals (HSB, DENV-1; 25.53 % and HTAR, DENV-1; 32.1 %).

Topics: Dengue; Dengue Virus; Epidemiological Monitoring; Hospitals; Humans; Malaysia; Real-Time Polymerase Chain Reaction; RNA, Viral; Seroepidemiologic Studies; Serogroup; Serum

Efforts to stamp dengue in many dengue endemic countries has met little success. There is a need to re-examine and understand how the public at large view the dengue prevention efforts. This study aimed to examine the demographic factors, theoretical constructs of the Health Belief Model and knowledge about dengue and how these influence the practice of dengue prevention.. A national telephone survey was carried out with 2,512 individuals of the Malaysian public aged 18-60 years.. The majority (73%) of the Malaysian public had a total dengue prevention score of 51-100 (of a possible score of 1-100). Multivariate analysis suggests significant correlates of higher dengue prevention practices with demographic background, perception of susceptibility to dengue, perceived density of mosquitoes in the neighbourhood and knowledge about dengue. Households of lower income of which the majority (40.7%) were from the rural areas, were associated with the highest odds [OR = 1.33; 95%CI = 1.09-1.67; p = 0.004] of dengue prevention. Dengue prevention practices were also less likely to be undertaken in neighbourhoods where the responders perceived there is no and/or low density of mosquitoes. Dengue prevention practices are also less likely to be practiced by skilled workers [OR = 0.78; 95%CI = 0.63-0.95; p = 0.029] compared to those unemployed. Higher perceived susceptibility to dengue was associated with higher dengue prevention practices and participants with higher dengue knowledge were found to have a higher level of involvement in dengue prevention practices.. Results from the study suggest that in formulating approaches to contain dengue, strategies should be developed to cultivate dengue prevention practices among urban population and target areas with low density of mosquitoes where public perceived a less likely chance of getting dengue. Dengue prevention campaigns should focus on messages highlighting the risk of contracting dengue and education to increase knowledge about dengue.

Topics: Adult; Animals; Culicidae; Demography; Dengue; Disease Transmission, Infectious; Female; Health Knowledge, Attitudes, Practice; Humans; Linear Models; Malaysia; Male; Middle Aged; Models, Psychological; Multivariate Analysis; Population Density

Characterization of 14,079 circulating dengue viruses in a cross-border surveillance program, UNITEDengue, revealed that the 2013 outbreaks in Singapore and Malaysia were associated with replacement of predominant serotype. While the predominant virus in Singapore switched from DENV2 to DENV1, DENV2 became predominant in neighboring Malaysia. Dominance of DENV2 was most evident on the southern states where higher fatality rates were observed.

Topics: Dengue; Dengue Virus; Disease Outbreaks; Humans; Malaysia; Phylogeny; Serotyping; Singapore

Dengue causes significantly more human disease than any other arboviruses. It causes a spectrum of illness, ranging from mild self-limited fever, to severe and fatal dengue hemorrhagic fever, as evidenced by vascular leakage and multifactorial hemostatic abnormalities. There is no specific treatment available till date. Evidence shows that chemokines CXCL10, CXCL11 and their receptor CXCR3 are involved in severity of dengue, but their genetic association with the susceptibility of vascular leakage during dengue infection has not been reported. We genotyped 14 common variants of these candidate genes in 176 patients infected with dengue. rs4859584 and rs8878 (CXCL10) were significantly associated with vascular permeability of dengue infection (P<0.05); while variants of CXCL11 showed moderate significance of association (P=0.0527). Haplotype blocks were constructed for genes CXCL10 and CXCL11 (5 and 7 common variants respectively). Haplotype association tests performed revealed that, "CCCCA" of gene CXCL10 and "AGTTTAC" of CXCL11 were found to be significantly associated with vascular leakage (P=0.0154 and 0.0366 respectively). In summary, our association study further strengthens the evidence of the involvement of CXCL10 and CXCL11 in the pathogenesis of dengue infection.

Topics: Adult; Alleles; Capillary Permeability; Case-Control Studies; Chemokine CXCL10; Chemokine CXCL11; Dengue; Dengue Virus; Female; Gene Expression; Gene Frequency; Genetic Predisposition to Disease; Haplotypes; Humans; Ligands; Malaysia; Male; Receptors, CXCR3; Severity of Illness Index

Knowledge on the extent, distribution and mechanisms of insecticide resistance is essential for successful insecticide-based dengue control interventions. Here, we report an extensive resistance profiling of the dengue vectors Aedes aegypti and Aedes albopictus across Malaysia and establish the contribution of knockdown resistance mechanism revealing significant contrast between both species.. Aedes mosquitoes were collected from four states in Malaysia in 2010 using ovitraps and tested against six major insecticides using WHO bioassays. Knockdown resistance (kdr) was investigated in both species.. A moderate resistance to temephos was detected from samples collected in 2010 in Penang, Kuala Lumpur, Johor Bharu and Kota Bharu (1.5 < RR < 3.3). A widespread and multiple resistances was observed in Ae. aegypti particularly against pyrethroids, DDT and bendiocarb. Mosquitoes from Kuala Lumpur consistently had the highest resistance levels and was the only population showing a moderate resistance to malathion (91% mortality). The resistance profile of Ae. albopictus contrasted to Ae. aegypti with full susceptibility to pyrethroids except in Kuala Lumpur where moderate resistance is observed. PBO synergist assays suggest metabolic resistance mechanisms play a major role in resistance in both species. Two kdr mutations, F1534C and V1016G, were detected in Ae. aegypti across Malaysia but neither of these mutations were found in Ae. albopictus. Additionally, signatures of selection were detected on the Voltage-gated sodium channel gene in Ae. aegypti but not in Ae. albopictus. The presence of the 1534C allele was significantly associated with pyrethroid resistance and an additive effect to pyrethroid resistance was observed in individuals containing both kdr alleles.. Findings from this study will help to design and implement successful insecticide-based interventions against Ae. aegypti and Ae. albopictus to improve dengue control across Malaysia.

Topics: Aedes; Alcohol Oxidoreductases; Alleles; Animals; Biological Assay; Dengue; Gene Expression Regulation; Genotype; Insect Vectors; Insecticide Resistance; Insecticides; Larva; Malaysia; Pesticide Synergists; Piperonyl Butoxide; Species Specificity

Wolbachia are maternally transmitted bacteria found in most arthropods and nematodes, but little is known about their distribution and reproductive dynamics in the Malaysian dengue vector Aedes albopictus. In this study, polymerase chain reaction (PCR) was used to determine the presence of Wolbachia from field collected Ae. albopictus from various parts of the country using wsp specific primers. Ae. albopictus had Wolbachia infection ranging from 60 to 100%. No sequence diversity of wsp gene was found within all wAlbA and wAlbB sequences. Our findings suggest that Wolbachia infection amongst the Malaysian Ae. albopictus were not homogenously distributed in all districts in Malaysia. The presence of Wolbachia in different organs of Ae. albopictus was also determined. Wolbachia were only found in the ovaries and midguts of the mosquitoes, while absent in the salivary glands. The effects of Wolbachia on Ae. albopictus fecundity, longevity and egg viability were studied using infected and uninfected colonies. The removal of Wolbachia from Ae. albopictus resulted in reduced fecundity, longevity and egg viability, thus. Wolbachia seem to play a vital role in Ae. albopictus reproductive system.

Topics: Aedes; Animals; Dengue; Genetic Variation; Genotype; Humans; Insect Vectors; Malaysia; Polymerase Chain Reaction; Wolbachia

We examined variations in dengue vector control costs and resource consumption between the District Health Departments (DHDs) and Local Authorities (LAs) to assist informed decision making as to the future roles of these agencies in the delivery of dengue vector control services in Malaysia. Data were collected from the vector control units of DHDs and LAs in 8 selected districts. We captured costs and resource consumption in 2010 for premise inspection for mosquito breeding sites, fogging to destroy adult mosquitoes and larviciding of potential breeding sites. Overall, DHDs spent US$5.62 million or US$679 per case and LAs spent US$2.61 million or US$499 per case. The highest expenditure for both agencies was for fogging, 51.0% and 45.8% of costs for DHDs and LAs, respectively. The DHDs had higher resource costs for human personnel, vehicles, pesticides, and equipment. The findings provide some evidence to rationalize delivery of dengue vector control services in Malaysia.

Topics: Animals; Costs and Cost Analysis; Dengue; Humans; Insect Vectors; Malaysia; Mosquito Control

To determine the effectiveness of using sticky traps and the NS1 dengue antigen kit for the surveillance of Aedes mosquitoes for dengue control.. Apartments were selected in a dengue-endemic area, and sticky traps were set to capture adult Aedes mosquitoes. NS1 dengue antigen kit was used to detect dengue antigen in mosquitoes, and positive mosquitoes were serotyped using real-time RT-PCR.. The sticky traps were effective in capturing Aedes aegypti, and a minimum of three traps per floor was sufficient. Multiple serotypes were found in individual mosquitoes.. The sticky trap and the NS1 dengue antigen test kit can be used as surveillance tool in dengue control programmes. This proactive method will be better suited for control programmes than current reactive methods.

Topics: Aedes; Animals; Dengue; Dengue Virus; Feasibility Studies; Insect Vectors; Malaysia; Pilot Projects; Polymerase Chain Reaction; RNA, Viral; Specimen Handling

Dengue is prevalent among Malaysia's indigenous peoples, known as the Orang Asli, and it poses a serious health threat to them. The study aims to look at the socio-demographic factors, health beliefs, and knowledge about dengue and its association to dengue prevention practices among Orang Asli communities in Peninsular Malaysia.. A cross-sectional survey was conducted in 16 randomly selected Orang Asli villages from eight states in Peninsular Malaysia from April 2012 until February 2013.. A total of 560 Orang Asli were interviewed and 505 completed the survey. Slightly above half of the participants (n = 280, 55.4%) had a total dengue prevention score of 51-100 (of a possible score of 0-100). Multivariate analysis findings showed dengue knowledge, perceived barriers to perform dengue prevention, fogging frequency, and perceived susceptibility to dengue fever as significant factors associated to dengue prevention practices. Participants with a lower dengue knowledge score (score 0-18) were less likely (OR = 0.63, 95%CI = 0.44-0.92 vs. score 19-36, P = 0.015) to practice dengue prevention. Participants with low perceived barriers to prevent dengue (score of 1-5) were more likely (OR = 2.06, 95%CI = 1.21-3.53, vs. score of 6-10, P = 0.008) to practice dengue prevention. Villages that were not fogged (OR = 0.49, 95%CI = 0.24-0.99, P = 0.045) or rarely fogged (OR = 0.40, 95%CI = 0.22-0.75, P = 0.004) had lower dengue prevention practices than villages that were fogged often. Participants with low perceived susceptibility of acquiring dengue (score of 1-5) were less likely (OR = 0.54, 95%CI = 0.33-0.89 vs. score of 6-10, P = 0.018) to practice dengue prevention measures.. Findings imply that educational and health programmes should focus on enhancing dengue knowledge and perceived susceptibility of acquiring dengue and reducing perceived barriers to performing dengue prevention practices among the Orang Asli. More outreach on mosquito control campaigns should be carried out especially in villages where mosquito fogging is frequent.

Topics: Adolescent; Adult; Cross-Sectional Studies; Dengue; Female; Health Knowledge, Attitudes, Practice; Humans; Logistic Models; Malaysia; Male; Mosquito Control; Odds Ratio; Population Groups; Young Adult

While visiting Malaysia, a 22-year-old previously healthy Japanese man developed myalgia, headache, and fever, leading to a diagnosis of classical dengue fever. After improvement and returning to Japan after a five day hospitalization, he developed productive cough several days after defervescing from dengue. Computed tomography (CT) thorax scan showed multiple lung cavities. A sputum smear revealed leukocytes with phagocytized gram-positive cocci in clusters, and grew an isolate Staphylococcus aureus sensitive to semi-synthetic penicillin; he was treated successfully with ceftriaxone and cephalexin. This second reported case of pneumonia due to S. aureus occurring after dengue fever, was associated both with nosocomial exposure and might have been associated with dengue-associated immunosuppression. Clinicians should pay systematic attention to bacterial pneumonia following dengue fever to establish whether such a connection is causally associated.

Topics: Dengue; Fever; Humans; Japan; Malaysia; Male; Pneumonia, Staphylococcal; Staphylococcus aureus; Travel; Young Adult

Wolbachia-based vector control strategies have been proposed as a mean to augment the existing measures for controlling dengue vector. Prior to utilizing Wolbachia in novel vector control strategies, it is crucial to understand the Wolbachia-mosquito interactions. Many studies have only focused on the prevalence of Wolbachia in female Aedes albopictus with lack of attention on Wolbachia infection on the male Ae. albopictus which also affects the effective expression of Wolbachia induced- cytoplasmic incompatibility (CI). In this study, field surveys were conducted to screen for the infection status of Wolbachia in female and male Ae. albopictus from various habitats including housing areas, islands and seashore.. Adult Ae. albopictus (n=104) were collected using human landing catches and hand aspirator. Standard ovitraps were also set in the selected areas for five days and the larvae were identified to species level. All the collected Ae. albopictus were screened for the presence of Wolbachia using multiplex polymerase chain reaction (PCR) and gene sequencing of Wolbachia surface protein (wsp) gene.. A 100 per cent positivity of Wolbachia infection was observed for individual Ae. albopictus screened. For pooled mosquitoes, 73 of the 76 pools (female) and 83 of the 87 pools (male) were positive with Wolbachia infection. The wsp gene sequence of the Wolbachia strain isolated from individual and pooled mosquitoes showed a 100 per cent homology with Wolbachia sp. of Ae. albopictus isolated from various geographical regions. Phylogenetic analysis based on wsp gene fragments showed that the isolates were clustered into groups A and B, respectively.. The results indicated that Wolbachia infection was widespread in Ae. albopictus population both in female and male Ae. albopictus. All the infected females were superinfected with both A and B strains while the infected males showed a combination of superinfection of A and B strains and single infection of B strain.

Topics: Aedes; Animals; Dengue; Female; Humans; Insect Vectors; Malaysia; Male; Phylogeny; Wolbachia

Dengue fever, an arbovirus disease transmitted by Aedes mosquitoes, has recently spread rapidly, especially in the tropical countries of the Americas and Asia-Pacific regions. It is endemic in Malaysia, with an annual average of 37,937 reported dengue cases from 2007 to 2012. This study measured the overall economic impact of dengue in Malaysia, and estimated the costs of dengue prevention. In 2010, Malaysia spent US$73.5 million or 0.03% of the country's GDP on its National Dengue Vector Control Program. This spending represented US$1,591 per reported dengue case and US$2.68 per capita population. Most (92.2%) of this spending occurred in districts, primarily for fogging. A previous paper estimated the annual cost of dengue illness in the country at US$102.2 million. Thus, the inclusion of preventive activities increases the substantial estimated cost of dengue to US$175.7 million, or 72% above illness costs alone. If innovative technologies for dengue vector control prove efficacious, and a dengue vaccine was introduced, substantial existing spending could be rechanneled to fund them.

Topics: Aedes; Animals; Cost of Illness; Dengue; Dengue Vaccines; Endemic Diseases; Humans; Insect Vectors; Malaysia; Mosquito Control

The incidence of dengue is rising steadily in Malaysia since the first major outbreak in 1973. Despite aggressive measures taken by the relevant authorities, Malaysia is still facing worsening dengue crisis over the past few years. There is an urgent need to evaluate dengue cases for better understanding of clinic-laboratory spectrum in order to combat this disease.. A retrospective analysis of dengue patients admitted to a tertiary care teaching hospital during the period of six years (2008 - 2013) was performed. Patient's demographics, clinical and laboratory findings were recorded via structured data collection form. Patients were categorized into dengue fever (DF) and dengue hemorrhagic fever (DHF). Appropriate statistical methods were used to compare these two groups in order to determine difference in clinico-laboratory characteristics and to identify independent risk factors of DHF.. A total 667 dengue patients (30.69 ± 16.13 years; Male: 56.7 %) were reviewed. Typical manifestations of dengue like fever, myalgia, arthralgia, headache, vomiting, abdominal pain and skin rash were observed in more than 40 % patients. DHF was observed in 79 (11.8 %) cases. Skin rash, dehydration, shortness of breath, pleural effusion and thick gall bladder were more significantly (P < 0.05) associated with DHF than DF. Multivariate regression analysis demonstrated presence of age > 40 years (OR: 4.1, P < 0.001), secondary infection (OR: 2.7, P = 0.042), diabetes mellitus (OR: 2.8, P = 0.041), lethargy (OR: 3.1, P = 0.005), thick gallbladder (OR: 1.7, P = 0.029) and delayed hospitalization (OR: 2.3, P = 0.037) as independent predictors of DHF. Overall mortality was 1.2 % in our study.. Current study demonstrated that DF and DHF present significantly different clinico-laboratory profile. Older age, secondary infection, diabetes mellitus, lethargy, thick gallbladder and delayed hospitalization significantly predict DHF. Prior knowledge of expected clinical profile and predictors of DHF/DSS development would provide information to identify individuals at higher risk and on the other hand, give sufficient time to clinicians for reducing dengue related morbidity and mortality.

Topics: Adolescent; Adult; Age Factors; Demography; Dengue; Dengue Virus; Diabetes Mellitus, Type 2; Disease Outbreaks; Female; Humans; Incidence; Malaysia; Male; Middle Aged; Odds Ratio; Regression Analysis; Retrospective Studies; Risk Factors; Severe Dengue; Young Adult

Monoclonal antibody-escape variant of dengue virus type 1 (MabEV DEN-1) was discovered and isolated in an outbreak of dengue in Klang Valley, Malaysia from December 2004 to March 2005. This study was done to investigate whether DEN152 (an isolate of MabEV DEN-1) is a product of recombination event or not. In addition, the non-synonymous mutations that correlate with the monoclonal antibody-escape variant were determined in this study. The genomes of DEN152 and two new DEN-1 isolates, DENB04 and DENK154 were completely sequenced, aligned, and compared. Phylogenetic tree was plotted and the recombination event on DEN152 was investigated. DEN152 is sub-grouped under genotype I and is closely related genetically to a DEN-1 isolated in Japan in 2004. DEN152 is not a recombinant product of any parental strains. Four amino acid substitutions were unique only to DEN 152. These amino acid substitutions were (Ser)[326](Leu), (Ser)[340](Leu) at the deduced E protein, (Ile)[250](Thr) at NS1 protein, and (Thr)[41](Ser) at NS5 protein. Thus, DEN152 is an isolate of the emerging monoclonal antibody-escape variant DEN-1 that escaped diagnostic laboratory detection.

Topics: Amino Acid Substitution; Antibodies, Monoclonal; Antibodies, Viral; Dengue; Dengue Virus; Disease Outbreaks; Genome, Viral; Humans; Malaysia; Mutation, Missense; Phylogeny; Sequence Alignment; Sequence Analysis, DNA; Sequence Homology; Serogroup; Viral Envelope Proteins

Copy number variation (CNV) is a form of genetic variation in addition to single nucleotide polymorphisms. The significance of CNV in the manifestation of a number of diseases is only recently receiving considerable attention. We genotyped 163 dengue patients from Peninsular Malaysia for genes possibly linked to dengue infection using quantitative real-time PCR. Here, we report a serendipitous discovery of a novel rare CNV of the ABCF1 gene among the dengue patients. Among these patients, two had a gain of 1 copy (CN = 3) and one had lost 1 copy (CN = 1), indicating that a rare CNV of the ABCF1 gene was detected among dengue patients from Peninsular Malaysia. Although the gene is suspected to regulate inflammatory responses and pathogen-induced cytokine storm, its relevance to dengue requires further investigation.

Topics: ATP-Binding Cassette Transporters; Dengue; DNA Copy Number Variations; Genetic Predisposition to Disease; Genetic Variation; Genotype; Humans; Malaysia

With its elusive pathogenesis, dengue imposes serious healthcare, economic and social burden on endemic countries. This study describes the clinical and immunological parameters of a dengue cohort in a Malaysian city, the first according to the WHO 2009 dengue classification.. This longitudinal descriptive study was conducted in two Malaysian hospitals where patients aged 14 and above with clinical symptoms suggestive of dengue were recruited with informed consent. Among the 504 participants, 9.3% were classified as non-dengue, 12.7% without warning signs, 77.0% with warning signs and 1.0% with severe dengue based on clinical diagnosis. Of these, 37% were misdiagnosed as non-dengue, highlighting the importance of both clinical diagnosis and laboratory findings. Thrombocytopenia, prolonged clotting time, liver enzymes, ALT and AST served as good markers for dengue progression but could not distinguish between patients with and without warning signs. HLA-A*24 and -B*57 were positively associated with Chinese and Indians patients with warning signs, respectively, whereas A*03 may be protective in the Malays. HLA-A*33 was also positively associated in patients with warning signs when compared to those without. Dengue NS1, NS2A, NS4A and NS4B were found to be important T cell epitopes; however with no apparent difference between with and without warning signs patients. Distinction between the 2 groups of patients was also not observed in any of the cytokines analyzed; nevertheless, 12 were significantly differentially expressed at the different phases of illness.. The new dengue classification system has allowed more specific detection of dengue patients, however, none of the clinical parameters allowed distinction of patients with and without warning signs. While the HLA-A*33 may be predictive marker for development of warning signs; larger studies will be needed to support this findings.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Biomarkers; Case-Control Studies; Cohort Studies; Comorbidity; Demography; Dengue; Dengue Virus; Disease Progression; Endemic Diseases; Female; Gene Frequency; HLA-A Antigens; HLA-B Antigens; Humans; Immunoglobulin M; Interferon-gamma; Malaysia; Male; Middle Aged; Reproducibility of Results; T-Lymphocytes; Young Adult

Demographic, economic and behavioural factors are central features underpinning the successful management and biological control of dengue. This study aimed to examine these factors and their association with the seroprevalence of this disease.. We conducted a cross-sectional telephone survey of households in a 3 km radius of the schools where we had conducted serological tests on the student population in a previous study. Households were surveyed about their socio-demographics, knowledge, practices, and Health Belief Model (HBM) constructs. The results were then associated with the prevalence rate of dengue in the community, as marked by IgG seropositivity of the students who attended school there.. A total of 1,400 complete responses were obtained. The community's IgG seropositivity was significantly positively associated with high household monthly income, high-rise residential building type, high surrounding vegetation density, rural locality, high perceived severity and susceptibility, perceived barriers to prevention, knowing that a neighbour has dengue, frequent fogging and a higher level of knowledge about dengue. In the multivariate analyses, three major correlates of the presence of IgG seropositivity in the community: (1) high-rise residential apartment house type or condominium buildings; (2) the main construct of the HBM, perceived severity and susceptibility; and (3) the additional constructs of the HBM, lack of preventive measures from the community level and having a neighbour with dengue as a cue to action. Weak correlations were found between self-practices to prevent dengue and the level of dengue seropositivity in the community, and between HBM constructs and knowledge (r = 0.09).. The residential environment factor and the constructs of the HBM are useful and important elements in developing interventions to prevent and control dengue. The study also sheds light on the importance of the need for approaches that ensure the translation of knowledge into practice.

Topics: Adult; Antibodies, Viral; Cross-Sectional Studies; Dengue; Family Characteristics; Female; Health Knowledge, Attitudes, Practice; Humans; Immunoglobulin G; Interviews as Topic; Malaysia; Male; Middle Aged; Multivariate Analysis; Schools; Young Adult

Toxorhynchites splendens larvae are a natural predator of dengue vector mosquito larvae, Aedes albopictus. This study was carried out to evaluate the predation rate of Tx. splendens third instar larvae on Ae. albopictus larvae in 24 h. Each predator was offered prey at a density between 10 to 50 individuals. Predation rate of Tx. splendens were also tested with two manipulated factors; various types of container and different water volumes. The experiment was evaluated in man-made containers (tin cans, plastic drinking glasses and rubber tires) and natural container (bamboo stumps) which were filled with different water volumes (full, half full, 1/4 full, and 1/8 full). The prey density and the characteristics of the container were found as significant factors which influence the predation rate of Tx. splendens. The predator consumed significantly more prey at higher prey densities (40 and 50 preys) compared to the lowest density (10 preys) (F=3.935, df=4, p=0.008). The results showed significantly higher consumption in horizontal shaped container of rubber tire than in vertical shape of bamboo stumps (F=3.100, df=3, p=0.029). However, the water volume had no significant effect on predation rate of Tx. splendens (F=1.736, df=3, p=0.162). We generally suggest that Tx. splendens is best to be released in discarded tires or any other containers with horizontal shape design with wide opening since Tx. splendens can become more effective in searching prey in this type of container design. This predator is also a suitable biocontrol candidates to be introduced either in wet and dry seasons in Malaysia.

Topics: Aedes; Animals; Culicidae; Dengue; Female; Humans; Insect Vectors; Larva; Malaysia; Mosquito Control; Predatory Behavior; Seasons; Water

Dengue fever (DF) is a major vector-borne disease in Malaysia. The incidences of DF in Malaysia are caused by viruses transmitted through the bites of infected female Aedes albopictus and Ae. aegypti mosquitoes. This study aims to establish the spatial density of mosquito population or breteau index (BI) in the areas of Kuala Lumpur using geographic information system (GIS), remote sensing (RS) and spatial statistical tools.. The 2010 weekly report data of BI obtained from the Ministry of Health (MoH) and the 2010 monthly rainfall data obtained from Malaysia Meteorological Services Department were analyzed using RS and spatial statistical tools to show the spatial correlation of dengue in each zone in Kuala Lumpur. The Kernel density was implemented to identify the better dengue hotspot localities.. RESULTS indicated a strong significant positive relationship between the number of localities with high BI and monthly rainfall (r = 0.64; p = 0.024). In addition, types of landuse did not appear to influence the mosquito's population (Built-up: r = 0.16, p = 0.118; Cleared area: r = - 0.107, p = 0.304; Vegetation dense: r = - 0.206, p = 0.046; Vegetation sparse: r = 0.023, p = 0.823; and Water: r = 0.246, p = 0.016).. In the present study, several hotspots identified will be beneficial to assist the local health authorities to reduce and eradicate mosquitoes in these areas. These results will provide valuable information through the application of advanced tools in combating Aedes mosquitoes.

Topics: Aedes; Animals; Cities; Demography; Dengue; Disease Eradication; Female; Geographic Information Systems; Incidence; Insect Vectors; Malaysia; Population Density; Remote Sensing Technology

The latest revised version of the World Health Organization's dengue classification was released in 2009. A handful of studies have taken initiatives to evaluate the old and revised guidelines to determine early signs and symptoms of severe dengue. This retrospective study aimed to compare the classification of dengue using both the 1997 and 2009 guidelines in a selected cohort of dengue patients from Peninsular Malaysia between 2008 and 2012.. Adult dengue patients were recruited from tertiary hospitals in two different states, Selangor and Kelantan, in Peninsular Malaysia. Their clinical manifestations were assessed.. A total of 281 confirmed dengue patients were enrolled; the mean duration of illness at admission was five days. Of these, 88.6%, 10.7%, and 0.7% were classified according to the 1997 guidelines as having dengue fever (DF), dengue hemorrhagic fever (DHF), and dengue shock syndrome (DSS), respectively. When the WHO 2009 guidelines were applied, 17.1%, 78.3%, and 4.6% were classified as dengue without warning signs, dengue with warning signs, and severe dengue, respectively.. Our data suggests that the revised WHO 2009 guidelines stratify a much larger proportion of patients into a category that requires a higher level of medical and nursing care.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Dengue; Female; Guidelines as Topic; Hospitalization; Humans; Malaysia; Male; Middle Aged; Retrospective Studies; Severe Dengue; World Health Organization; Young Adult

The transmission of dengue disease is influenced by complex interactions among vector, host and virus. Land use such as water bodies or certain agricultural practices have been identified as likely risk factors for dengue because of the provision of suitable habitats for the vector. Many studies have focused on the land use factors of dengue vector abundance in small areas but have not yet studied the relationship between land use factors and dengue cases for large regions. This study aims to clarify if land use factors other than human settlements, e.g. different types of agricultural land use, water bodies and forest are associated with reported dengue cases from 2008 to 2010 in the state of Selangor, Malaysia. From the correlative relationship, we aim to generate a prediction risk map. We used Boosted Regression Trees (BRT) to account for nonlinearities and interactions between the factors with high predictive accuracies. Our model with a cross-validated performance score (Area Under the Receiver Operator Characteristic Curve, ROC AUC) of 0.81 showed that the most important land use factors are human settlements (model importance of 39.2%), followed by water bodies (16.1%), mixed horticulture (8.7%), open land (7.5%) and neglected grassland (6.7%). A risk map after 100 model runs with a cross-validated ROC AUC mean of 0.81 (±0.001 s.d.) is presented. Our findings may be an important asset for improving surveillance and control interventions for dengue.

Topics: Communicable Disease Control; Dengue; Humans; Malaysia; Models, Statistical; Population Density; ROC Curve; Spatial Analysis

During a dengue outbreak in 2005 in the East-coast region of Peninsular Malaysia, one of the worst hit areas in the country at that time, we undertook a prospective study. We aimed to describe the bleeding outcome and changes in the liver and hematologic profiles that were associated with major bleeding outcome during the outbreak. All suspected cases of dengue admitted into the only referral hospital in the region during the outbreak were screened for WHO 2002 criteria and serology. Liver function, hematologic profile and severity of bleeding outcome were carefully documented. The association between symptoms, liver and hematologic impairments with the type of dengue infection (classical vs. hemorrhagic) and bleeding outcome (major vs. non-major) was tested. Dengue fever was confirmed in 183 cases (12.5/100,000 population) and 144 cases were analysed. 59.7% were dengue hemorrhagic fever, 3.5% were dengue shock syndrome and there were 3 in-hospital deaths. Major bleeding outcome (gastrointestinal bleeding, intracranial bleeding or haemoptysis) was present in 14.6%. Elevated AST, ALT and bilirubin were associated with increasing severity of bleeding outcome (all P < 0.05). Platelet count and albumin level were inversely associated with increasing severity of bleeding outcome (both P < 0.001). With multivariable analysis, dengue hemorrhagic fever was more likely in the presence of abdominal pain (OR 1.1, 95% CI 0.02- 1.6) and elevated AST (OR 1.0, 95% CI 1.0-1.1) but the presence of pleural effusion (OR 5.8, 95% CI: 1.1-29.9) and elevated AST (OR 1.008, 95% CI: 1.005-1.01) predicted a severe bleeding outcome. As a conclusion, the common presence of a severe hemorrhagic form of dengue fever may explain the rising death toll in recent outbreaks and the worst impairment in liver and hematologic profiles was seen in major bleeding outcome.

Topics: Adolescent; Adult; Cross-Sectional Studies; Dengue; Disease Outbreaks; Female; Hemorrhage; Humans; Liver; Liver Function Tests; Malaysia; Male; Middle Aged; Prospective Studies; Young Adult

In order to reduce the risk of dengue outbreak recurrence in a dengue outbreak prone area, the members of the community need to sustain certain behavior to prevent mosquito from breeding. Our study aims to identify the factors associated with larval control practices in this particular community. A cross-sectional study involves 322 respondents living in a dengue outbreak prone area who were interviewed using a pretested questionnaire. The level of knowledge about Aedes mosquitoes, dengue transmission, its symptoms, and personal preventive measures ranges from fair to good. The level of attitude towards preventive measures was high. However, reported level of personal larval control practices was low (33.2%). Our multiple logistic regression analysis showed that only those with a good level of attitude towards personal preventive measure and frequent attendance to health campaigns were significantly associated with the good larval control practices. We conclude that, in a dengue outbreak prone area, having a good attitude towards preventive measures and frequent participation in health campaigns are important factors to sustain practices on larval control.

Topics: Adult; Aedes; Animals; Cities; Cross-Sectional Studies; Dengue; Disease Outbreaks; Female; Health Knowledge, Attitudes, Practice; Humans; Larva; Logistic Models; Malaysia; Male; Middle Aged; Mosquito Control; Young Adult

BACKGROUND & OBJECTIVESI: Transovarial transmission of dengue virus in the Aedes vectors is now a well-documented phenomenon reported from many parts of the endemic areas in the world, which played an important role in initiating and maintaining the outbreak in human populations. This study investigated the factors affecting breeding habitats and the relationship with transovarial dengue virus in larvae of Aedes aegypti and Ae. albopictus.. Larval surveillance was conducted in dengue outbreak areas in Malaysia from 2008 until 2009. Sampling was carried out based on habitat type, water condition (substrate type), canopy coverage, temperature and pH at breeding habitats. RT-PCR was performed to detect presence of transovarial dengue virus in larvae collected in the study areas.. A total of 789 breeding habitats were identified during this study and the majority of these breeding sites were plastic containers (57.46%). Aedes albopictus dominated most of the water condition surveyed, while Ae. aegypti indicated preference toward habitats with clear water. Aedes aegypti was selective in selecting ovipositional sites compared to Ae. albopictus where shaded areas were shown to be the most preferred. From a total of 363 mosquito larvae pools, 23 (6.3%) pools were positive for dengue virus where 18 of them were from Ae. albopictus and five were from Ae. aegypti mosquito larvae pools.. This study indicated the presence of transovarial transmission of dengue virus in immature Ae. aegypti and Ae. albopictus in the field. This study also showed that combination of water conditions, canopy coverage, temperature and pH of breeding habitats were the factors affecting the larval population. The study suggested that larval survey programme could serve as a tool not only to monitor the local dengue vector distribution but also to provide objective information for taking appropriate action by the community against dengue vectors.

Topics: Aedes; Animals; Dengue; Dengue Virus; Ecosystem; Insect Vectors; Larva; Malaysia; Reverse Transcriptase Polymerase Chain Reaction; RNA, Viral

Spatio-temporal patterns of dengue risk in Malaysia were studied both at the address and the sub-district level in the province of Selangor and the Federal Territory of Kuala Lumpur. We geocoded laboratory-confirmed dengue cases from the years 2008 to 2010 at the address level and further aggregated the cases in proportion to the population at risk at the sub-district level. Kulldorff's spatial scan statistic was applied for the investigation that identified changing spatial patterns of dengue cases at both levels. At the address level, spatio-temporal clusters of dengue cases were concentrated at the central and south-eastern part of the study area in the early part of the years studied. Analyses at the sub-district level revealed a consistent spatial clustering of a high number of cases proportional to the population at risk. Linking both levels assisted in the identification of differences and confirmed the presence of areas at high risk for dengue infection. Our results suggest that the observed dengue cases had both a spatial and a temporal epidemiological component, which needs to be acknowledged and addressed to develop efficient control measures, including spatially explicit vector control. Our findings highlight the importance of detailed geographical analysis of disease cases in heterogeneous environments with a focus on clustered populations at different spatial and temporal scales. We conclude that bringing together information on the spatio-temporal distribution of dengue cases with a deeper insight of linkages between dengue risk, climate factors and land use constitutes an important step towards the development of an effective risk management strategy.

Topics: Aedes; Animals; Cluster Analysis; Dengue; Geographic Mapping; Humans; Insect Vectors; Malaysia; Risk Factors; Spatio-Temporal Analysis

Malaysia a dengue endemic country with dengue infections in pregnancy on the rise. The present study was aimed at determining dengue seroprevalence (IgG or IgM) during pregnancy and its neonatal transmission in dengue seropositive women.. Maternal with paired cord blood samples were tested for dengue antibodies (IgG and IgM) using an enzyme-linked immunosorbent assay (ELISA). Maternal age, parity, occupation, ethnic group, and gestational age were recorded. Data on neonatal Apgar score and admissions to the Neonatal Intensive Care Unit (NICU) were analyzed.. Out of 358 women recruited, about 128 (35.8%) patients were seropositive. Twelve patients (3.4%) had recent infections (IgM positive) and another 116 women (32.4%) were with past infections (IgG positive). All babies born to seropositive mothers had positive IgG paired cord blood; however, no IgM seropositivity was observed. All neonates had good Apgar scores and did not require NICU admission.. In this study, 35.8% pregnant women were found to be dengue seropositive. However, transplacental transfer of IgG antibodies had no detrimental effect on the neonatal outcomes.

Topics: Adult; Antibodies, Viral; Dengue; Dengue Virus; Enzyme-Linked Immunosorbent Assay; Female; Humans; Immunoglobulin G; Infant, Newborn; Malaysia; Pregnancy; Seroepidemiologic Studies

The Water-associated Disease Index (WADI) was developed to identify and visualize vulnerability to different water-associated diseases by integrating a range of social and biophysical determinants in map format. In this study vulnerability is used to encompass conditions of exposure, susceptibility, and differential coping capacity to a water-associated health hazard. By assessing these conditions, the tool is designed to provide stakeholders with an integrated and long-term understanding of subnational vulnerabilities to water-associated disease and contribute to intervention strategies to reduce the burden of illness. The objective of this paper is to describe and validate the WADI tool by applying it to dengue. A systemic ecohealth framework that considers links between people, the environment and health was applied to identify secondary datasets, populating the index with components including climate conditions, land cover, education status and water use practices. Data were aggregated to create composite indicators of exposure and of susceptibility in a Geographic Information System (GIS). These indicators were weighted by their contribution to dengue vulnerability, and the output consisted of an overall index visualized in map format. The WADI was validated in this Malaysia case study, demonstrating a significant association with dengue rates at a sub-national level, and illustrating a range of factors that drive vulnerability to the disease within the country. The index output indicated high vulnerability to dengue in urban areas, especially in the capital Kuala Lumpur and surrounding region. However, in other regions, vulnerability to dengue varied throughout the year due to the influence of seasonal climate conditions, such as monsoon patterns. The WADI tool complements early warning models for water-associated disease by providing upstream information for planning prevention and control approaches, which increasingly require a comprehensive and geographically broad understanding of vulnerability for implementation.

Topics: Dengue; Geographic Information Systems; Geographic Mapping; Health Status Indicators; Humans; Malaysia; Risk Assessment; Vulnerable Populations

Dengue fever is a major public health problem in Malaysia. This study aimed to assess factors affecting knowledge, attitudes, and practices regarding dengue fever among a selected population in Malaysia. A descriptive, community-based, cross sectional study was conducted with 300 participants from three different geographical settings in urban, semi-urban, and rural areas within the states of Selangor and Kuala Lumpur. The questionnaire included questions on demographic data, knowledge, attitudes, and practices regarding dengue fever. Mean age of respondents was 34.4 (+/- 5.7) years, and the age ranged from 18 to 65 years. The majority of respondents were married (54.7%), Malays (72.7%) and heard about dengue fever (89.7%). Television was the common source of information about dengue fever (97.0%). Participants answered 4 out of 15 items of knowledge incorrectly. There was no significant association between knowledge score and socio-demographic factors. About one-fifth of the respondents (24%) believed that immediate treatment is not necessary for dengue fever, and the majority of them were not afraid of the disease (96.0%). Attitudes toward dengue fever were significantly associated with the level of education and employment status (p < 0.05). Practice was associated significantly with age, marital status, and geographic area (p < 0.05) and knowledge on dengue fever (p = 0.030). There is a need to increase health promotion activities through campaigns and social mobilization to increase knowledge regarding dengue fever. This would help to mold positive attitudes and cultivate better preventive practices among the public to eliminate dengue in the country.

Topics: Adolescent; Adult; Age Factors; Aged; Consumer Health Information; Cross-Sectional Studies; Dengue; Female; Health Knowledge, Attitudes, Practice; Humans; Malaysia; Male; Middle Aged; Residence Characteristics; Socioeconomic Factors; Young Adult

We studied the diversity of Aedes breeding sites in various urban, suburban, and rural areas over time between February 2009 and February 2010 in the dengue endemic areas of Penang Island, Malaysia. We categorized the breeding sites and efficiency, and identified the key breeding containers. Among the 3 areas, the rural areas produced the highest container index (55), followed by suburban (42) and urban (32) areas. The numbers of key premises and containers were significantly higher (P < 0.000) in rural areas. The class 1 containers were identified as the key containers with higher productivity and efficiency, although class 2 and class 4 are the highest in numbers. Aedes aegypti immatures were found mostly in drums, water reservoirs, and polyethylene sheets, while mixed breeding was more common in buckets and empty paint cans in urban and suburban areas. Aedes albopictus was found mainly in miscellaneous containers such as drums, empty paint cans, and covers in all areas. The main potential containers indoors were drums, water reservoirs, and empty paint cans, and containers outdoors included empty paint cans, drums, and polyethylene sheets.

Topics: Animals; Culicidae; Dengue; Ecosystem; Humans; Insect Vectors; Larva; Malaysia; Population Density; Pupa; Reproduction

To analyze trends of dengue incidences and deaths in Malaysia from 2000 to 2010 as well as the predominant dengue virus serotypes during the last decade.. We used the national data on annual reported cases, deaths, incidence rate, mortality rate, and case fatality rate of dengue fever (DF) and dengue hemorrhagic fever (DHF) as well as dengue virus serotypes prevalent in Malaysia during the last decade. Trend/ regression lines were fitted to investigate the trend of dengue incidences and deaths due to the disease for a 11-year period (2000-2010). For the distribution of national incidence rate, mortality rate, and case fatality rate of DF and DHF, descriptive statistics using mean and 95% confidence intervals (CI 39) for means, and range were applied.. The number of dengue cases and number of deaths have increased, on average, by 14% and 8% per year respectively. The average annual incidence rate of DF per 100 000 populations was higher as compared to that of DHF. Conversely, the yearly mean mortality rate of DHF per 100 000 populations was greater than that of DF. The simultaneous circulation of all four dengue serotypes has been found in Malaysia. But a particular dengue virus serotype predominates for at least two years before it becomes replaced by another serotype.. The dengue situation in Malaysia has worsened with an increasing number of reported cases and deaths during the last decade. The increasing trend of dengue highlights the need for a more systematic surveillance and reporting of the disease.

Topics: Cohort Studies; Dengue; Dengue Virus; Humans; Incidence; Malaysia

This qualitative study aimed to provide an in-depth understanding of the meaning of dengue fever (DF) amongst people living in a dengue endemic region, dengue prevention and treatment-seeking behaviours. The Health Belief Model was used as a framework to explore and understand dengue prevention behaviours.. A total of 14 focus group discussions were conducted with 84 Malaysian citizens of different socio-demographic backgrounds between 16(th) December, 2011 and 12(th) May, 2012.. The study revealed that awareness about DF and prevention measures were high. The pathophysiology of dengue especially dengue haemorrhagic fever (DHF) and dengue shock syndrome (DSS) were rarely known; as a result, it was seen as deadly by some but was also perceived as easily curable by others without a basis of understanding. Young adults and elderly participants had a low perception of susceptibility to DF. In general, the low perceived susceptibility emerged as two themes, namely a perceived natural ability to withstand infection and a low risk of being in contact with the dengue virus vector, Aedes spp. mosquitoes. The barriers to sustained self-prevention against dengue prevention that emerged in focus groups were: i) lack of self-efficacy, ii) lack of perceived benefit, iii) low perceived susceptibility, and iv) unsure perceived susceptibility. Low perceived benefit of continued dengue prevention practices was a result of lack of concerted action against dengue in their neighborhood. Traditional medical practices and home remedies were widely perceived and experienced as efficacious in treating DF.. Behavioural change towards attaining sustainability in dengue preventive practices may be enhanced by fostering comprehensive knowledge of dengue and a change in health beliefs. Wide use of unconventional therapy for DF warrants the need to enlighten the public to limit their reliance on unproven alternative treatments.

Topics: Adult; Aged; Animals; Dengue; Disease Transmission, Infectious; Female; Focus Groups; Health Education; Health Knowledge, Attitudes, Practice; Humans; Malaysia; Male; Middle Aged; Patient Acceptance of Health Care; Young Adult

Dengue has emerged as one of the major public health problems in Malaysia. The Ministry of Health, Malaysia, is committed in monitoring and controlling this disease for many years. The objective of this study is to analyze the dengue outbreak pattern on a monthly basis in Subang Jaya in terms of their spatial dissemination and hotspot identification.. Collated dengue cases data covering a 5-year period (2006-2010) retrieved from a municipal surveillance system of Subang Jaya were georeferenced and then converted into Geographical Information System format. Average nearest neighbor (ANN) analysis and kernel density (KD) estimation were used to assess the spatial dissemination of dengue cases and detect dengue hotspots, respectively.. The spatial patterns of dengue fever cases during the 5-year period were spatially clustered (with R values < 1) based on the monthly frequency data. The hotspot map produced by the KD techniques showed a spatially diffused pattern.. The methodology used in the study and the result obtained could be useful not only for documentation by epidemiologists but also for active surveillance of dengue outbreak in a locality.

Topics: Aedes; Animals; Cluster Analysis; Dengue; Disease Outbreaks; Geographic Information Systems; Humans; Insect Vectors; Malaysia; Public Health; Retrospective Studies; Seasons; Spatial Analysis

Dengue fever is endemic in Malaysia, with frequent major outbreaks in urban areas. The major control strategy relies on health promotional campaigns aimed at encouraging people to reduce mosquito breeding sites close to people's homes. However, such campaigns have not always been 100% effective. The concept of self-efficacy is an area of increasing research interest in understanding how health promotion can be most effective. This paper reports on a study of the impact of self-efficacy on dengue knowledge and dengue preventive behaviour.. We recruited 280 adults from 27 post-outbreak villages in the state of Terengganu, east coast of Malaysia. Measures of health promotion and educational intervention activities and types of communication during outbreak, level of dengue knowledge, level and strength of self-efficacy and dengue preventive behaviour were obtained via face-to-face interviews and questionnaires. A structural equation model was tested and fitted the data well (χ(2) = 71.659, df = 40, p = 0.002, RMSEA = 0.053, CFI = 0.973, TLI = 0.963). Mass media, local contact and direct information-giving sessions significantly predicted level of knowledge of dengue. Level and strength of self-efficacy fully mediated the relationship between knowledge of dengue and dengue preventive behaviours. Strength of self-efficacy acted as partial mediator in the relationship between knowledge of dengue and dengue preventive behaviours.. To control and prevent dengue outbreaks by behavioural measures, health promotion and educational interventions during outbreaks should now focus on those approaches that are most likely to increase the level and strength of self-efficacy.

Topics: Adult; Behavior Therapy; Cross-Sectional Studies; Dengue; Disease Outbreaks; Female; Health Education; Health Knowledge, Attitudes, Practice; Humans; Malaysia; Male; Middle Aged; Self Efficacy

Topics: Aedes; Animals; Communicable Disease Control; Dengue; Dengue Vaccines; Dengue Virus; Humans; Malaysia; World Health Organization

The number of dengue cases has been increasing on a global level in recent years, and particularly so in Malaysia, yet little is known about the effects of weather for identifying the short-term risk of dengue for the population. The aim of this paper is to estimate the weather effects on dengue disease accounting for non-linear temporal effects in Selangor, Kuala Lumpur and Putrajaya, Malaysia, from 2008 to 2010. We selected the weather parameters with a Poisson generalized additive model, and then assessed the effects of minimum temperature, bi-weekly accumulated rainfall and wind speed on dengue cases using a distributed non-linear lag model while adjusting for trend, day-of-week and week of the year. We found that the relative risk of dengue cases is positively associated with increased minimum temperature at a cumulative percentage change of 11.92% (95% CI: 4.41-32.19), from 25.4 °C to 26.5 °C, with the highest effect delayed by 51 days. Increasing bi-weekly accumulated rainfall had a positively strong effect on dengue cases at a cumulative percentage change of 21.45% (95% CI: 8.96, 51.37), from 215 mm to 302 mm, with the highest effect delayed by 26-28 days. The wind speed is negatively associated with dengue cases. The estimated lagged effects can be adapted in the dengue early warning system to assist in vector control and prevention plan.

Topics: Dengue; Dengue Virus; Humans; Malaysia; Nonlinear Dynamics; Poisson Distribution; Seasons; Weather

Dengue is a serious public health problem in Malaysia. The aim of this study was to compare the vertical infestation of Aedes population in 2 apartments in Kuala Lumpur with different status of dengue incidence (i.e., high-dengue-incidence area and area with no reported dengue cases). The study was also conducted to assess the relationship between environmental factors such as rainfall, temperature, and humidity and Aedes population that may influence Aedes infestation. Surveillance with a mosquito larvae trapping device was conducted for 28 continuous weeks (January to July 2012) in Vista Angkasa (VA) and Inderaloka (IL) apartments located in Kuala Lumpur, Malaysia. The results indicated that both Aedes spp. could be found from ground to higher floor levels of the apartments, with Aedes aegypti being more predominant than Ae. albopictus. Data based on mixed and single breeding of Aedes spp. on different floors did not show any significant difference. Both rainfall (R3; i.e., the amount of rainfall collected during the previous 3 wk before the surveillance period began) and RH data showed significant relationship with the number of Aedes larvae collected in VA and IL. No significant difference was found between the numbers of Aedes larvae in both study areas as well as maximum and minimum temperatures. Results also indicated adaptations of Ae. aegypti to the ecosystem at each elevation of high-rise buildings, with Ae. albopictus staying inside of apartment units.

Topics: Aedes; Animals; Dengue; Housing; Humans; Insect Vectors; Malaysia; Weather

Dengue fever is endemic in Malaysia and poses a significant problem to the national health system. Because of its nonspecific clinical features, it creates clinical and administrative uncertainties. We evaluated the role of an emergency department short-stay ward (EDSSW) in the management of dengue fever in the Universiti Kebangsaan Malaysia Medical Centre (UKMMC).. A retrospective study was carried out on suspected dengue patients who were admitted to UKMMC EDSSW, between January and March 2010. Data were retrieved from the EDSSW Monthly Census Book and patients' medical records. Patients were categorized as follows: group 1, which included patients who received treatment in the EDSSW only, and group 2, which included patients who received initial treatment in EDSSW and were subsequently admitted to the inpatient (IP) wards.. A total of 147 patients' records were available. The total length of stay was 32.2 h in group 1 and 100.5 h in group 2. For group 2 patients, a median of 21.8 h was spent in EDSSW and 78.8 h was spent in IP. All patients in group 1 and group 2 were discharged well. The total EDSSW stay was 4309 patient-hours; IP stay totalled 5137 patient-hours. The use of the EDSSW reduced the IP burden in managing dengue by 45.6%.. EDSSW limit the number and burden of dengue patients requiring formal IP admissions while acting as a 'safety net' for inappropriate discharges and unnecessary admissions.

Topics: Adult; Cross-Sectional Studies; Dengue; Efficiency, Organizational; Emergency Service, Hospital; Female; Humans; Length of Stay; Malaysia; Male; Patient Admission; Retrospective Studies

Chikungunya virus (CHIKV) and dengue virus (DENV) co-circulate in areas endemic with the Aedes mosquito vectors. Both viruses cause similar illnesses which may be difficult to distinguish clinically. CHIKV is also associated with persistent arthralgia.. To compare and describe factors which differentiate between DENV and CHIKV infections on presentation; and to describe predictors of persistent arthralgia in CHIKV patients.. Patients aged >14 years diagnosed with acute CHIKV and DENV infections in Kuala Lumpur, Malaysia were retrospectively identified. Clinical and laboratory data were obtained from medical records, and compared. CHIKV patients were telephoned 15-24 months later and interviewed about persistent symptoms. Logistic regression analysis was performed.. A total of 53 CHIKV and 113 DENV patients were included. CHIKV patients were older and more likely to be female. CHIKV was independently associated with arthralgia and rash, while DENV was associated with myalgia, raised aspartate transaminase, and leucopaenia. Forty CHIKV patients were followed up, with a median duration of self-reported arthralgia of 3 months (range, 0-24 months). Eighteen (45%) had persistent arthralgia beyond 4 months, for which age >40 years was an independent predictor. At 1 year, 9 (22.5%) patients had arthralgia.. In Kuala Lumpur, selected clinical and laboratory predictors help to distinguish between DENV and CHIKV infections. Persistent arthralgia was a frequent sequel of CHIKV infection in this cohort.

Topics: Adult; Alphavirus Infections; Arthralgia; Chikungunya virus; Decision Support Techniques; Dengue; Diagnosis, Differential; Female; Follow-Up Studies; Humans; Interviews as Topic; Malaysia; Male; Middle Aged; Retrospective Studies; Young Adult

This study was conducted to determine the inhibitory effects of ribavirin and hydroxyurea on dengue virus replication in Aedes aegypti mosquitoes. Female Ae. aegypti mosquitoes were infected with dengue-2 virus and fed ribavirin at a dose of 0.3 mg/ml and/or hydroxyurea at a dose of 6 mg/ml via artificial membrane feeding technique. The virus in infected mosquitoes was isolated using C6/36 cell culture. Peroxidase-antiperoxidase (PAP) staining was used to detect dengue-infected C6/36 cells and to quantify the level of infection by determining the presence of infected cells. In mosquitoes treated with ribavirin alone, hydroxyurea alone or both drugs in combination had reductions in dengue infection rates of 87.72, 89.47 and 95.61%, respectively. The mortalities of female Ae. aegypti mosquitoes fed with these drugs were significantly higher than the control. Ribavirin also had an inhibitory effect on the fecundity of female Ae. aegypti mosquitoes.

Topics: Aedes; Animals; Antiviral Agents; Dengue; Dengue Virus; Female; Humans; Hydroxyurea; Insect Vectors; Malaysia; Ribavirin; Virus Replication

This case study investigates the connections among urban planning, governance and dengue fever in an emerging market context in the Global South. Key informant interviews were conducted with leading figures in public health, urban planning and governance in the planned city of Putrajaya, Malaysia. Drawing on theories of urban political ecology and ecosocial epidemiology, the qualitative study found the health of place - expressed as dengue-bearing mosquitoes and dengue fever in human bodies in the urban environment - was influenced by the place of health in a hierarchy of urban priorities.

Topics: City Planning; Dengue; Humans; Interviews as Topic; Malaysia; Models, Organizational; Politics; Public Health; Urban Health

The domestic dengue vector Aedes aegypti mosquitoes breed in indoor containers. However, in northern peninsular Malaysia, they show equal preference for breeding in both indoor and outdoor habitats. To evaluate the epidemiological implications of this peridomestic adaptation, we examined whether Ae. aegypti exhibits decreased survival, gonotrophic activity, and fecundity due to lack of host availability and the changing breeding behavior.. This yearlong field surveillance identified Ae. aegypti breeding in outdoor containers on an enormous scale. Through a sequence of experiments incorporating outdoors and indoors adapting as well as adapted populations, we observed that indoors provided better environment for the survival of Ae. aegypti and the observed death patterns could be explained on the basis of a difference in body size. The duration of gonotrophic period was much shorter in large-bodied females. Fecundity tended to be greater in indoor acclimated females. We also found increased tendency to multiple feeding in outdoors adapted females, which were smaller in size compared to their outdoors breeding counterparts.. The data presented here suggest that acclimatization of Ae. aegypti to the outdoor environment may not decrease its lifespan or gonotrophic activity but rather increase breeding opportunities (increased number of discarded containers outdoors), the rate of larval development, but small body sizes at emergence. Size is likely to be correlated with disease transmission. In general, small size in Aedes females will favor increased blood-feeding frequency resulting in higher population sizes and disease occurrence.

Topics: Aedes; Analysis of Variance; Animals; Body Size; Data Collection; Dengue; Feeding Behavior; Female; Fertility; Geography; Housing; Larva; Life Cycle Stages; Malaysia; Oviposition; Ovum; Reproduction; Survival Analysis; Wings, Animal

Topics: Adult; Animals; Culicidae; Dengue; Dengue Virus; Diagnosis, Differential; Exanthema; Fever; Headache; Humans; Malaysia; Male; Nausea; Singapore; Travel; Tropical Medicine

In the last few years in Malaysia, dengue fever has increased dramatically and has caused huge public health concerns. The present study aimed to establish a spatial distribution of dengue cases in the city of Kuala Lumpur using a combination of Geographic Information System (GIS) and spatial statistical tools. Collation of data from 1,618 dengue cases in 2009 was obtained from Kuala Lumpur City Hall (DBKL). These data were processed and then converted into GIS format. Information on the average monthly rainfall was also used to correlate with the distribution pattern of dengue cases. To asses the spatial distribution of dengue cases, Average Nearest Neighbor (ANN) Analysis was applied together with spatial analysis with the ESRI ArcGIS V9.3 programme. Results indicated that the distribution of dengue cases in Kuala Lumpur for the year 2009 was spatially clustered with R value less than 1 (R = 0.42; z-scores = - 4.47; p < 0.001). Nevertheless, when this pattern was further analyzed according to month by each zone within Kuala Lumpur, two distinct patterns were observed which include a clustered pattern (R value < 1) between April to June and a dispersed pattern (R value > 1) between August and November. In addition, the mean monthly rainfall has not influenced the distribution pattern of the dengue cases. Implementation of control measures is more difficult for dispersed pattern compared to clustered pattern. From this study, it was found that distribution pattern of dengue cases in Kuala Lumpur in 2009 was spatially distributed (dispersed or clustered) rather than cases occurring randomly. It was proven that by using GIS and spatial statistic tools, we can determine the spatial distribution between dengue and population. Utilization of GIS tools is vital in assisting health agencies, epidemiologist, public health officer, town planner and relevant authorities in developing efficient control measures and contingency programmes to effectively combat dengue fever.

Topics: Animals; Dengue; Humans; Malaysia; Seasons; Topography, Medical

It is important to obtain frequent measurements of the abundance, distribution, and seasonality of mosquito vectors to determine the risk of disease transmission. The number of cases of dengue infection has increased in recent years on Penang Island, Malaysia, with recurring epidemics. However, ongoing control attempts are being critically hampered by the lack of up-to-date information regarding the vectors. To overcome this problem, we examined the current situation and distribution of dengue vectors on the island. Residences throughout the urban, suburban, and rural areas were inspected through wet and dry seasons between February 2009 and February 2010. Two vectors were encountered in the survey, with Aedes aegypti present in especially high numbers mostly in urban areas. Similar observations were noted for Ae. albopictus in rural areas. The former species was more abundant in outdoor containers, while the latter showed almost equivalent abundance both outdoors and indoors. The dengue virus was active in both urban and rural areas, and the number of cases of infection was higher in areas where Ae. aegypti was predominant. The abundance of immature Ae. albopictus was positively correlated with rainfall (r2 = 0.461; P < 0.05), but this was not the case for Ae. aegypti. For both species, the size of immature populations tended to increase with increasing intensity of rain, but heavy rains resulted in population loss. In addition to updating data regarding the larval habitats and locations (outdoors and indoors), this study highlighted the importance of spatial vector control stratification, which has the potential to reduce costs in control programs.

Topics: Aedes; Animals; Dengue; Dengue Virus; Ecosystem; Housing; Humans; Insect Vectors; Larva; Malaysia; Population Density; Seasons; Species Specificity

Dengue is the most important mosquito-borne viral disease. In the absence of specific drugs or vaccines, control focuses on suppressing the principal mosquito vector, Aedes aegypti, yet current methods have not proven adequate to control the disease. New methods are therefore urgently needed, for example genetics-based sterile-male-release methods. However, this requires that lab-reared, modified mosquitoes be able to survive and disperse adequately in the field.. Adult male mosquitoes were released into an uninhabited forested area of Pahang, Malaysia. Their survival and dispersal was assessed by use of a network of traps. Two strains were used, an engineered 'genetically sterile' (OX513A) and a wild-type laboratory strain, to give both absolute and relative data about the performance of the modified mosquitoes. The two strains had similar maximum dispersal distances (220 m), but mean distance travelled of the OX513A strain was lower (52 vs. 100 m). Life expectancy was similar (2.0 vs. 2.2 days). Recapture rates were high for both strains, possibly because of the uninhabited nature of the site.. After extensive contained studies and regulatory scrutiny, a field release of engineered mosquitoes was safely and successfully conducted in Malaysia. The engineered strain showed similar field longevity to an unmodified counterpart, though in this setting dispersal was reduced relative to the unmodified strain. These data are encouraging for the future testing and implementation of genetic control strategies and will help guide future field use of this and other engineered strains.

Topics: Aedes; Animal Distribution; Animals; Animals, Genetically Modified; Climate; Dengue; Dengue Virus; Female; Humans; Infertility, Male; Insect Vectors; Malaysia; Male; Mosquito Control; Statistics, Nonparametric

Plasmodium knowlesi is a simian malaria parasite and is recently recognized as the fifth malaria parasite infecting humans. Manifestation of the infection may resemble other infection particularly dengue fever leading to inappropriate management and delay in treatment. We reported three cases of naturally acquired P. knowlesi in Hospital Universiti Sains Malaysia, Kubang Kerian, Kelantan, Malaysia. Clinical manifestations were quite similar in those cases. Microscopically, the diagnosis might be challenging. These cases were confirmed by polymerase chain reaction method which serves as a gold standard.

Topics: Adult; Aged; Antimalarials; Dengue; Diagnosis, Differential; Fever; Hospitals, Teaching; Humans; Malaria; Malaysia; Male; Middle Aged; Plasmodium knowlesi; Polymerase Chain Reaction; Tertiary Care Centers; Thrombocytopenia

Biweekly ovitrap surveillance (OS) was conducted for a year (August 2007 - September 2008) at two different dengue endemic sites in Shah Alam, Selangor, Malaysia, 50 km from Kuala Lumpur. Aedes aegypti collected from these 2 locations were raised to the F3 stage and subjected to a WHO standard bioassay method to determine lethal time (LT) against pyrethroids (permethrin 0.75%, cyfluthrin 0.15%), organophosphates (malathion 5.0%, fenitrothion 1.0%), carbamates (propoxur 0.1%, bendiocarb 0.1%) and organochlorine (DDT 4.0%). Insecticide susceptibilities were analyzed for one year. Aedes aegypti were resistant to DDT with a mortality range of 0 - 13.3% throughout the year at both sites. Susceptibilities to pyrethroids and carbamates varied throughout the year. In contrast, susceptibilities to pyrethroids and carbamates varied throughout the year: resistant to propoxur, bendiocarb and permethrin with mortality of < 80% in most months; but, showed incipient resistant to cyfluthrin in most months. Mosquitoes were consistently susceptible to malathion and fenitrothion, with complete mortality during most months. They were especially susceptible to malathion with LT50 values of 21.32 - 36.37 minutes, suggesting effectiveness of malathion for control of dengue.

Topics: Aedes; Animals; Carbamates; DDT; Dengue; Insecticide Resistance; Insecticides; Malaysia; Organophosphates; Pyrethrins; Seasons

A one year study was conducted to evaluate the impact of spray application of Bacillus thuringiensis israelensis (Bti), strain AM65-52 on vector populations and dengue transmission in a dengue endemic state in Malaysia. Residential sites with similar populations of Aedes aegypti (L.) and Aedes albopictus Skuse were studied. One site was treated with spray application of Bti into all outdoor target vector habitats, which consisted of natural and artificial containers. The other site was not treated. The impact of spray application was measured with an indoor and outdoor ovitrap index (OI) and epidemiologic data. Significant reductions in both Ae. aegypti and Ae. albopictus, OI were observed both indoors and outdoors, in treated sites compared to untreated sites (p < 0.05). OI reduction was achieved over time in the treated area. The OI was suppressed to below 10%. This was maintained for 4 weeks into the post-treatment phase. The outdoor OI at the untreated site remained at more than 40% for 38 weeks during the evaluation period. One dengue case occurred at the Bti treatment site at the beginning of the treatment phase, but no further cases were detected during the remainder of the treatment phase. However, there was an ongoing dengue outbreak in the untreated area with 15 serologically confirmed cases during weeks 37-54. Intensive fogging operations with pyrethroids at the untreated (Bti) site had a positive impact on Ae. albopictus, but not on Ae. aegypti.

Topics: Aedes; Animals; Bacillus thuringiensis; Chi-Square Distribution; Dengue; Endemic Diseases; Humans; Insect Vectors; Insecticides; Malaysia; Mosquito Control

Dengue fever is a recurring public health problem afflicting thousands of Malaysians annually. In this paper, the risk map for dengue fever in the peninsular Malaysian states of Selangor and Kuala Lumpur was modelled based on co-kriging and geographical information systems. Using population density and rainfall as the model's only input factors, the area with the highest risk for dengue infection was given as Gombak and Petaling, two districts located on opposite sides of Kuala Lumpur city that was also included in the risk assessment. Comparison of the modelled risk map with the dengue case dataset of 2010, obtained from the Ministry of Health of Malaysia, confirmed that the highest number of cases had been found in an area centred on Kuala Lumpur as predicted our risk profiling.

Topics: Aedes; Animals; Dengue; Disease Reservoirs; Geographic Information Systems; Geographic Mapping; Humans; Incidence; Insect Vectors; Malaysia; Models, Biological; Population Density; Rain; Risk Assessment

Topics: Animals; Brazil; Culicidae; Dengue; Disclosure; Evaluation Studies as Topic; Focus Groups; Guidelines as Topic; Humans; Informed Consent; Malaysia; Organisms, Genetically Modified; Public Opinion; Public Relations; Risk Assessment; West Indies

From 2005 to 2009, the Institute for Medical Research (IMR), Kuala Lumpur, Malaysia received 488 serum and blood samples from hospitalized patients on the East Coast of Peninsular Malaysia, suspected of having dengue infection. In this study we determined the prevailing dengue serotypes using a real time polymerase chain reaction assay (RT-PCR). All 4 dengue virus serotypes were found circulating during the study period; however the predominant serotype varied. In 2005 and 2006, the predominant serotypes circulating were DENV-1 and DENV-3, in 2007, DENV-1 and DENV-2 were predominant, and in 2008 and 2009, DENV-3 was the predominant serotype.

Topics: Dengue; Dengue Virus; Female; Humans; Malaysia; Male; Molecular Typing; Reverse Transcriptase Polymerase Chain Reaction; Serotyping

Primary prevention is the most effective measure in dengue prevention and control. The objectives were (i) to determine the level of knowledge and practice of dengue control amongst the study community, and (ii) to explore the factors affecting practice of dengue control in the study area. A cross-sectional study was conducted in a semi-urban Town of Malaysia, using a structured questionnaire covering sociodemography, knowledge related to dengue, knowledge related to Aedes mosquito and preventive measures against the disease. For comparison of survey responses, chi-square test was applied for categorical data. To explore the factors affecting the practice of dengue control, a linear regression model was introduced. Almost all of the respondents (95%) had heard about dengue. Overall, misconceptions of dengue transmission were identified and the practice of dengue control in the study population was insufficient. About half (50.5%) had misconceptions that Aedes can breed in dirty water and the preferred biting time is dusk or sunset (45.6%). Only 44.5% of the households surveyed had covered their water containers properly. Significant associations were found between knowledge scores of dengue and age (P = 0.001), education level (P = 0.001), marital status (P = 0.012), and occupation (P = 0.007). In regression analysis, only the knowledge of dengue was significantly and positively associated with practice on dengue control. A future study with larger samples and more variables to assess the knowledge, attitudes and practices of dengue control is recommended.

Topics: Adult; Aedes; Animals; Bites and Stings; Cross-Sectional Studies; Dengue; Female; Health Knowledge, Attitudes, Practice; Humans; Insect Repellents; Insect Vectors; Malaysia; Male; Middle Aged; Mosquito Control; Primary Prevention; Surveys and Questionnaires

Ovitrap surveillance was conducted in methodically selected areas in Bentong, Pahang, Malaysia from June 2008 till December 2009 in order to identify insular sites with stable Aedes aegypti population. Eleven sites were surveyed in Bentong district, Pahang, and one of these locations (N3º33' E101º54') was found to have an ovitrap index of Ae. aegypti and Aedes albopictus ranging from 8%-47% and 37%-78% respectively, indicating that this site could be a high-risk area for dengue outbreak. Ae. aegypti larvae were found in both indoor and outdoor ovitraps (p>0.05) while significant difference between the populations of Ae. albopictus larvae from indoors and outdoors was observed (p<0.01). Data collected in this study could provide important entomological information for designing an effective integrated vector control programme to combat Aedes mosquitoes in this area.

Topics: Aedes; Animals; Dengue; Disease Vectors; Ecosystem; Humans; Malaysia; Population Density

Serological tests for IgM and IgG are routinely used in clinical laboratories for the rapid diagnosis of dengue and can differentiate between primary and secondary infections. Dengue virus non-structural protein 1 (NS1) has been identified as an early marker for acute dengue, and is typically present between days 1-9 post-onset of illness but following seroconversion it can be difficult to detect in serum.. To evaluate the performance of a newly developed Panbio® Dengue Early Rapid test for NS1 and determine if it can improve diagnostic sensitivity when used in combination with a commercial IgM/IgG rapid test.. The clinical performance of the Dengue Early Rapid was evaluated in a retrospective study in Vietnam with 198 acute laboratory-confirmed positive and 100 negative samples. The performance of the Dengue Early Rapid in combination with the IgM/IgG Rapid test was also evaluated in Malaysia with 263 laboratory-confirmed positive and 30 negative samples.. In Vietnam the sensitivity and specificity of the test was 69.2% (95% CI: 62.8% to 75.6%) and 96% (95% CI: 92.2% to 99.8) respectively. In Malaysia the performance was similar with 68.9% sensitivity (95% CI: 61.8% to 76.1%) and 96.7% specificity (95% CI: 82.8% to 99.9%) compared to RT-PCR. Importantly, when the Dengue Early Rapid test was used in combination with the IgM/IgG test the sensitivity increased to 93.0%. When the two tests were compared at each day post-onset of illness there was clear differentiation between the antigen and antibody markers.. This study highlights that using dengue NS1 antigen detection in combination with anti-glycoprotein E IgM and IgG serology can significantly increase the sensitivity of acute dengue diagnosis and extends the possible window of detection to include very early acute samples and enhances the clinical utility of rapid immunochromatographic testing for dengue.

Topics: Adolescent; Adult; Aged; Antibodies, Viral; Antigens, Viral; Child; Child, Preschool; Clinical Laboratory Techniques; Dengue; Dengue Virus; Early Diagnosis; Female; Humans; Immunoassay; Immunoglobulin G; Immunoglobulin M; Infant; Malaysia; Male; Middle Aged; Retrospective Studies; Sensitivity and Specificity; Vietnam; Viral Nonstructural Proteins; Young Adult

Early detection of a dengue outbreak is an important first step towards implementing effective dengue interventions resulting in reduced mortality and morbidity. A dengue mathematical model would be useful for the prediction of an outbreak and evaluation of control measures. However, such a model must be carefully parameterized and validated with epidemiological, ecological and entomological data. A field study was conducted to collect and analyse various parameters to model dengue transmission and outbreak. Dengue prone areas in Kuala Lumpur, Pahang, Kedah and Johor were chosen for this study. Ovitraps were placed outdoor and used to determine the effects of meteorological parameters on vector breeding. Vector population in each area was monitored weekly for 87 weeks. Weather stations, consisting of a temperature and relative humidity data logger and an automated rain gauge, were installed at key locations in each study site. Correlation and Autoregressive Distributed Lag (ADL) model were used to study the relationship among the variables. Previous week rainfall plays a significant role in increasing the mosquito population, followed by maximum humidity and temperature. The secondary data of rainfall, temperature and humidity provided by the meteorological department showed an insignificant relationship with the mosquito population compared to the primary data recorded by the researchers. A well fit model was obtained for each locality to be used as a predictive model to foretell possible outbreak.

Topics: Aedes; Animals; Dengue; Disease Outbreaks; Disease Vectors; Humans; Malaysia; Meteorological Concepts; Models, Theoretical; Population Dynamics; Risk Assessment

A field evaluation on the effectiveness of a modified approach of chemical fogging of insecticides against the conventional method was carried out in the Seremban district within the state of Negeri Sembilan, Malaysia from 7th February 2003 to 7th September 2003. In the 3 months period, November 2002 to January 2003, prior to institution of modified approach of chemical fogging, 27 of 42 (64.3%) dengue outbreaks were successfully controlled within the stipulated time frame of 14 days by the conventional approach of thermal chemical fogging. However, during the period when the modified approach of chemical fogging was instituted, 25 of 27 (92.6%) dengue outbreaks within the same district were successfully controlled within the 14-days time-line. Statistically, the modified approach of chemical fogging significantly improved the success rate of achieving dengue outbreak control within the stipulated time frame (chi2 = 5.65, p = 0.01745). The modified approach of chemical fogging also appeared to reduce the number of dengue cases recorded in the same district. This small pilot study shows that the modified approach of chemical fogging reduced cost in carrying out each fogging activity to control dengue outbreak. It also substantially reduced the required time taken to complete each fogging activity in comparison to the conventional approach. Thus, it enabled similar number of workers to cover more localities simultaneously affected by the outbreaks. In addition, the modified approach reduced the exposure time to hazardous insecticides for each worker doing hand-held thermal fogging.

Topics: Animals; Dengue; Humans; Insecticides; Malaysia; Mosquito Control; Pilot Projects

This cross-sectional study was to compare and categorize potential breeding sites of dengue vectors, Aedes aegypti and Aedes albopictus at three different places, namely, an urban (Taman Permas Jaya, Johor Bahru, Johor), a suburban (Kg. Melayu Gelang Patah, Johor Bahru, Johor) and a rural (Felda Simpang Waha, Kota Tinggi, Johor) habitats in Malaysia. Larval surveys were conducted once in every two months at each habitat over a period of 11 months from August 2000 until June 2001. There was a significant difference between the three study sites in terms of potential breeding sites inspected (p<0.001). There were more potential breeding sites found in the rural area when compared to the urban and suburban habitats. The mean Potential Container Index (PCI) values in descending order were as follows: rural habitat (57.72)>suburban (29.35)>urban habitat (16.97). Both breeding sites and potential breeding sites were the nominator and the total number of containers inspected as the denominator in the formula of PCI, thus the latter could be a potential indicator to initiate anti-dengue campaign at the community level to rid off potential Aedes breeding sites. The three most common potential breeding sites of Aedes species were similar for urban and suburban habitats (flower pots, pails and bowls respectively). However, flower pots, vases and tyres were the three most common potential breeding sites for the rural habitat. Another finding in this study was that various types of larval habitats were found indoors and outdoors for both species.

Topics: Aedes; Animals; Dengue; Insect Vectors; Malaysia; Reproduction; Water

The mosquito Ae. albopictus is usually adapted to the peri-domestic environment and typically breeds outdoors. However, we observed its larvae in most containers within homes in northern peninsular Malaysia. To anticipate the epidemiological implications of this indoor-breeding, we assessed some fitness traits affecting vectorial capacity during colonization process. Specifically, we examined whether Ae. albopictus exhibits increased survival, gonotrophic activity and fecundity due to the potential increase in blood feeding opportunities.. In a series of experiments involving outdoors and indoors breeding populations, we found that Ae. albopictus lives longer in the indoor environment. We also observed increased nighttime biting activity and lifetime fecundity in indoor/domestic adapted females, although they were similar to recently colonized females in body size.. Taken together these data suggest that accommodation of Ae. albopictus to indoor/domestic environment may increase its lifespan, blood feeding success, nuisance and thus vectorial capacity (both in terms of increased vector-host contacts and vector population density). These changes in the breeding behavior of Ae. albopictus, a potential vector of several human pathogens including dengue viruses, require special attention.

Topics: Aedes; Animals; Body Size; Breeding; Dengue; Female; Fertility; Geography; Humans; Insect Vectors; Malaysia; Male

The human leukocyte antigen alleles have been implicated as probable genetic markers in predicting the susceptibility and/or protection to severe manifestations of dengue virus (DENV) infection. In this present study, we aimed to investigate for the first time, the genotype variants of HLA Class 1(-A and -B) of DENV infected patients against healthy individuals in Malaysia.. This study was carried out with 92 dengue disease patients and 95 healthy controls from three different ethnic groups (Malay, Chinese and Indian) in Malaysia. All patients with clinical and laboratory confirmation of DENV infection were typed for the HLA-A and B loci, using polymerase chain reaction-sequence specific primer techniques. In our total population, a significant increase for HLA-B*53 (P = 0.042, Pc = 1.008) allele and a significant decrease for A*03 (P = 0.015, Pc = 0.18, OR = 5.23, 95% CI = 1.19-23.02) and B*18 (P = 0.017, Pc = 0.408) alleles were noted in DHF patients as compared to healthy donors. We also observed that in the Malay DHF patients, allele B*13 (P = 0.049, Pc = 1.176, OR = 0.18, 95% CI = 0.03-0.90) was present at a significantly higher frequency in this population while allele HLA-B*18 (P = 0.024, Pc = 0.576) was seen to be negatively associated with DHF.. These are the first findings on genetic polymorphisms in our population and we conclude that: (1) In our total population, HLA-B*53 probably involve in disease susceptibility, while the HLA-A*03 and HLA-B*18 may confer protection from progression to severe disease; (2) In the Malay population, HLA-B*13 and B*18 are probably associated in disease susceptibility and protection, respectively. These results could furnish as a valuable predictive tool to identify ethnically different individuals at risk and/or protection from severe forms of DENV infection and would provide valuable informations for the design of future dengue vaccine.

Topics: Adolescent; Adult; Alleles; Case-Control Studies; Dengue; Dengue Virus; Female; Genetic Predisposition to Disease; Genotype; HLA-A Antigens; HLA-B Antigens; Humans; Immunity, Innate; Malaysia; Male; Middle Aged; Severe Dengue; Young Adult

A year-long ovitrap surveillance was conducted between November 2007 and October 2008 in two insular settlements (Kampung Pulau Ketam and Kampung Sungai Lima) within the Malaysian island of Pulau Ketam. Eighty standard ovitraps were placed indoors and outdoors of randomly selected houses/locations. Results demonstrated an endemic baseline Aedes population throughout the year without weekly large fluctuations. Kampung Pulau Ketam has high Aedes aegypti and Aedes albopictus population, but only Ae. aegypti was found in Kampung Sungai Lima. Aedes aegypti showed no preference for ovitraps placed indoor versus outdoor. However, as expected, significantly more outdoor ovitraps were positive for Ae. albopictus (p<0.05). Trends in Ae. albopictus and Ae. aegypti populations mirrored each other suggesting that common factors influenced these two populations.

Topics: Aedes; Animals; Dengue; Housing; Humans; Insect Vectors; Malaysia; Population Density; Time Factors

Ancestral sylvatic dengue virus type 1, which was isolated from a monkey in 1972, was isolated from a patient with dengue fever in Malaysia. The virus is neutralized by serum of patients with endemic DENV-1 infection. Rare isolation of this virus suggests a limited spillover infection from an otherwise restricted sylvatic cycle.

Topics: Animals; Dengue; Dengue Virus; Genome, Viral; Haplorhini; Human Growth Hormone; Humans; Malaysia; Neutralization Tests; Phylogeny

Dengue fever is a major public health threat in Malaysia, especially in the highly urbanized states of Selangor and the Federal Territory of Kuala Lumpur. It is believed that many seek treatment at the primary care clinics and are not admitted. This study aims at establishing the fact that primary care practitioners, as the first point of patient contacts, play a crucial role in advising patients suspected of having dengue to take early preventive measures to break the chain of dengue transmission. A total of 236 patients admitted to two government hospitals for suspected dengue fever were interviewed using a structured questionnaire over a one week period in December 2008. It was found that 83.9% of the patients had sought treatment at a Primary Care (PC) facility before admission to the hospital, with 68.7% of them seeking treatment on two or more occasions. The mean time period for seeking treatment at primary care clinic was one and a half (1.4) days of fever, compared to almost five (4.9) days for admission. The majority of patients (96-98%) reported that primary care practitioners had not given them any advice on preventive measures to be taken even though 51.9% of the patients had been told they could be having dengue fever. This study showed the need for primary care providers to be more involved in the control and prevention of dengue in the community, as these patients were seen very early in their illness compared to when they were admitted.

Topics: Cross-Sectional Studies; Dengue; Female; Humans; Malaysia; Male; Patient Acceptance of Health Care; Physician's Role; Primary Health Care

Although dengue is a common disease in South-East Asia, there is a marked absence of virological data from the Malaysian state of Sarawak located on the island of Borneo. From 1997 to 2002 we noted the co-circulation of DENV-2, DENV-3 and DENV-4 in Sarawak. To determine the origins of these Sarawak viruses we obtained the complete E gene sequences of 21 isolates. A phylogenetic analysis revealed multiple entries of DENV-2 and DENV-4 into Sarawak, such that multiple lineages co-circulate, yet with little exportation from Sarawak. Notably, all viral isolates were most closely related to those circulating in different localities in South-East Asia. In sum, our analysis reveals a frequent traffic of DENV in South-East Asia, with Sarawak representing a local sink population.

Topics: Dengue; Dengue Virus; Evolution, Molecular; Genetic Variation; Humans; Malaysia; Molecular Epidemiology; Phylogeny; RNA, Viral; Sequence Analysis, DNA; Serotyping; Viral Envelope Proteins

This study was undertaken to determine the impact of larvaciding using a Bti (Bacillus thuringiensis israelensis) formulation (VectoBac WG) against Aedes aegypti larvae in earthen jars containing aquatic plants. Aquatic plants commonly used for landscaping, Pistia stratiotes (L.) (Liliopsida: Araceae) and Sagittaria sp. (Liliopsida: Alismataceae) were placed inside earthen jars filled with 50 L tap water. All earthen jars were treated with Bti formulation at 8g/1000L. Untreated jars with and without aquatic plants were also set up as controls. Fifty laboratory-bred 2nd instar larvae were introduced into each earthen jar. All earthen jars were observed daily. Number of adults emerged was recorded and the larval mortality was calculated. The indicators of effectiveness of Bti for these studies were (i) residual activities of Bti, and (ii) larval mortality in earthen jars with or without aquatic plants. The treated earthen jars containing P. stratiotes and Sagittaria sp. showed significant residual larvicidal effect up to 7 weeks, in comparison to untreated control (p < 0.05). The larval mortality ranged from 77.34% - 100% for jars with aquatic plants vs 80.66% - 100% for jars without aquatic plant. Earthen jars treated with Bti without aquatic plants also exhibited significantly longer residual larvicidal activity of up to 10 weeks (p < 0.05). The larval mortality ranged from 12.66% - 100% for jars with aquatic plants vs 59.34% - 100% for jars without aquatic plant. Thus, earthen jars without aquatic plants exhibited longer residual larvicidal effect compared to those with aquatic plants. This study suggested that containers with aquatic plants for landscaping should be treated more frequently with Bti in view of the shortened residual activity.

Topics: Aedes; Alismataceae; Animals; Araceae; Bacillus thuringiensis; Ceramics; Dengue; Insect Vectors; Larva; Malaysia; Pest Control, Biological; Water

Although the disease burden of dengue is increasing, the impact on the quality of life (QoL) has not been investigated. A study to determine the QoL of confirmed dengue patients using the EuroQol visual thermometer scale was carried out at the University Malaya Medical Center. Of the 207 participants, 40% were ambulatory and 60% were hospitalized. Of eight health domains, 6.2 and 5.0 domains were affected in the hospitalized and ambulatory cohorts, respectively (P < 0.001), with cognition and interpersonal activities affected most. All patients experienced a drastic decrease in their QoL from the onset of symptoms. The QoL deteriorated to the lowest point (40% of healthy status) between the third and seventh days of illness. The duration of impaired QoL (9 days for ambulatory or 13 days for hospitalized patients) was longer than the duration of fever (5 and 7 days, respectively). Symptomatic dengue has major effects on patients' health.

Topics: Adolescent; Adult; Child; Child, Preschool; Cohort Studies; Dengue; Depression; Female; Humans; Infant; Infant, Newborn; Malaysia; Male; Middle Aged; Quality of Life

Topics: Animals; Animals, Genetically Modified; Culicidae; Dengue; Humans; Insect Vectors; Malaysia; Pest Control, Biological

The field bioefficacy of a wettable granule (WG) formulation of Bacillus thuringiensis israelensis (Bti), VectoBac WG (Bti strain AM65-52) against dengue vectors, Aedes aegypti and Ae albopictus; was evaluated in a suburban residential area (TST) and in a temporary settlement site (KB) in the state of Selangor, Malaysia. Pre-control ovitrap surveillance of the trial sites indicated a high population of both types of Aedes mosquitoes. The populations were monitored continuously by weekly ovitrapping. Bti was sprayed biweekly at a dosage of 500 g/ha by using a mist-blower. The spray application was targeted into outdoor larval habitats. If required, Bti formulation was also applied directly into indoor water-holding containers at 8 g/1,000 l. Based on ovitrap surveillance, a significant reduction in Aedes populations was evident 4 weeks after initiating the first Bti treatment. The ovitrap index (OI) and the larvae density decreased drastically in both trial sites. In TST, the indoor OI was significantly reduced from 57.50 +/- 7.50% to 19.13 +/- 5.49% (p<0.05), while the outdoor OI decreased from 38.89 +/- 11.11% to 15.36 +/- 5.93%. In KB, similarly, the OI was significantly reduced by more than half, from 66.66 +/- 6.67% to 30.26 +/- 2.99% (p< 0.05). In all cases, the reduction in OI was paralleled by reduction in larval density.

Topics: Aedes; Animals; Bacillus thuringiensis; Dengue; Endemic Diseases; Humans; Insect Vectors; Insecticides; Larva; Malaysia; Mosquito Control

This study presents a new approach to determine the significant prognosis factors in dengue patients utilizing the self-organizing map (SOM). SOM was used to visualize and determine the significant factors that can differentiate between the dengue patients and the healthy subjects. Bioimpedance analysis (BIA) parameters and symptoms/signs obtained from the 210 dengue patients during their hospitalization were used in this study. Database comprised of 329 sample (210 dengue patients and 119 healthy subjects) were used in the study. Accordingly, two maps were constructed. A total of 35 predictors (17 BIA parameters, 18 symptoms/signs) were investigated on the day of defervescence of fever. The first map was constructed based on BIA parameters while the second map utilized the symptoms and signs. The visualized results indicated that, the significant BIA prognosis factors for differentiating the dengue patients from the healthy subjects are reactance, intracellular water, ratio of the extracellular water and intracellular water, and ratio of the extracellular mass and body cell mass.

Topics: Algorithms; Decision Support Systems, Clinical; Dengue; Diagnosis, Computer-Assisted; Humans; Malaysia; Proportional Hazards Models; Risk Assessment; Risk Factors

This is a retrospective study of the gastrointestinal symptoms, signs and laboratory parameters in adult dengue patients admitted to Kuala Lumpur Hospital from 1st December 2004 to 31st December 2004. Clinical and laboratory parameters that may predict the need for intensive care were investigated. Six hundred sixty-six patients with clinical and biochemical features consistent with dengue infection were identified. Patients were stratified into those who required intensive care and those who were managed in non high dependency wards. Serum alanine aminotransaminase (ALT) levels were normal in 22.8% of patients and 5.9% of patients had acute fulminant hepatitis. More patients with dengue haemorrhagic fever (DHF) had elevated ALT levels as compared to patients with classic dengue fever (DF) (p = 0.012). Patients with DF had a statistically significant lower mean ALT level as compared to patients with DHF. Abdominal pain (p = 0.01) and tenderness (p<0.001), gastrointestinal bleed (p<0.001), jaundice (p<0.001), hepatomegaly (p<0.001) and ascites (p<0.001) were predictors of need for intensive care. We conclude that gastrointestinal manifestations are very common in dengue patients. Presence of abdominal pain and tenderness, gastrointestinal bleed, jaundice, hepatomegaly and ascites can be used to triage patients requiring intensive care.

Topics: Adult; Alanine Transaminase; Critical Care; Dengue; Female; Gastrointestinal Diseases; Humans; Liver Failure, Acute; Malaysia; Male; Patient Admission; Retrospective Studies

To estimate prevalence rate of recent dengue infection in parturients, as well as the vertical transmission rate, and to compare pregnancy outcomes among infected women.. A prospective cohort study was performed. Maternal and paired umbilical cord bloods were taken at delivery. A brief questionnaire on febrile illness and dengue in pregnancy was completed by participants. The samples were sent to a World Health Organization Collaborating Center for Arbovirus Reference and Research. Maternal sera were tested with a dengue-specific immunoglobulin M (IgM) capture test. The paired umbilical cord serum was tested to determine when the maternal sample was positive. Dengue reverse transcriptase polymerase chain reaction (PCR) was performed on all dengue IgM-positive sera. Pregnancy outcome was extracted from delivery records.. A total of 2,958 parturients were enrolled, and 2,531 paired maternal-umbilical cord blood samples were available for testing. Dengue-specific IgM was positive in 63 of 2,531 (2.5%, 95% confidence interval [CI] 1.9-3.2%) maternal samples. Only 1 of 64 (1.6%, 95% CI 0.0-9.5%) of the paired umbilical cord sera was IgM-positive. All reverse transcriptase PCR tests were negative. Fifty-six of 63 (88.9%) of dengue IgM-positive women did not report a febrile illness in pregnancy. Apart from a higher mean age in dengue IgM-positive women of 30.6+/-5.2 compared with 29.2+/-4.9 years (P=.025) compared with dengue IgM-negative women, all other characteristics were similar. Rates of preterm birth, mode of delivery, postpartum hemorrhage, low birth weight, and neonatal outcomes were not different.. Recent dengue infection was demonstrated in 2.5% of parturients, with a vertical transmission rate of 1.6%. Pregnancy outcome of recently infected women was not different.. II.

Topics: Adult; Dengue; Female; Humans; Immunoglobulin M; Infectious Disease Transmission, Vertical; Malaysia; Pregnancy; Pregnancy Complications, Infectious; Pregnancy Outcome; Prospective Studies; Reverse Transcriptase Polymerase Chain Reaction

Topics: Aedes; Animals; Dengue; Evaluation Studies as Topic; Female; Fertility; Genetic Engineering; Humans; Malaysia; Male; Mosquito Control

Dengue fever is endemic in many countries of South East Asia. In spite of the occasional epidemics, dengue maculopathy remains a rare entity.. A 31-year-old gentleman was admitted with a 6-day history of fever, generalised rash, headache and myalgia after a trip to Malaysia. There were no bleeding manifestations. The lowest platelet count was 71 x 10,000/ml, the haematocrit was 42.7%, and dengue serology was positive. On the 8th day of illness, he complained of bilateral blurred vision. Detailed visual examination showed visual acuity of right eye 6/30 and left eye 6/50. Fundoscopy revealed dilated veins, hyperaemic optic discs, flame and blot haemorrhages, soft exudates and macular ischaemia. After a course of high-dose steroids, the visual acuity as well as colour vision improved markedly.. The pathology of maculopathy is not obvious in this case, but an immunological reaction is suspected. There is a risk of residual visual impairment, and there is no definitive treatment. The use of high-dose steroids seemed to improve visual acuity and colour vision. However, it is not known whether immunosuppression improves the prognosis. Time for resolution is from 8 weeks to 4 months. Since there is an increase in the incidence of dengue fever in our region, coupled with rising international travel, one could postulate that global incidence of dengue-related maculopathy may become significant.. Ocular complications associated with dengue fever are rare but may result in permanent visual impairment. Dengue fever should be suspected in travellers, particularly those returning from endemic areas, and they should be systematically screened for maculopathy when visual disturbances arise.

Topics: Adult; Dengue; Humans; Macula Lutea; Malaysia; Male; Ophthalmoscopy; Steroids; Travel; Treatment Outcome; Vision Disorders

Topics: Dengue; Female; Humans; Malaysia; Obstetric Labor, Premature; Pregnancy; Pregnancy Complications, Infectious

Dengue virus infections are a major cause of morbidity and mortality in tropical and subtropical areas in the world. Attempts to develop effective vaccines have been hampered by the lack of understanding of the pathogenesis of the disease and the absence of suitable experimental models for dengue viral infection. The magnitude of T-cell responses has been reported to correlate with dengue disease severity. Sixty Malaysian adults with dengue viral infections were investigated for their dengue virus-specific T-cell responses to 32 peptides antigens from the structural and nonstructural regions from a dengue virus isolate. Seventeen different peptides from the C, E, NS2B, NS3, NS4A, NS4B, and NS5 regions were found to evoke significant responses in a gamma interferon enzyme-linked immunospot (ELISPOT) assay of samples from 13 selected patients with dengue fever (DF) and dengue hemorrhagic fever (DHF). NS3 and predominantly NS3(422-431) were found to be important T-cell targets. The highest peaks of T-cell responses observed were in responses to NS3(422-431) and NS5(563-571) in DHF patients. We also found almost a sevenfold increase in T-cell response in three DHF patients compared to three DF patient responses to peptide NS3(422-431). A large number of patients' T cells also responded to the NS2B(97-106) region. The ELISPOT analyses also revealed high frequencies of T cells that recognize both serotype-specific and cross-reactive dengue virus antigens in patients with DHF.

Topics: Adolescent; Adult; Amino Acid Sequence; Cross Reactions; Dengue; Dengue Virus; Enzyme-Linked Immunosorbent Assay; Humans; Interferon-gamma; Malaysia; Middle Aged; Molecular Sequence Data; Peptides; Severe Dengue; T-Lymphocytes; Viral Nonstructural Proteins; Viral Structural Proteins

Difficulties in the classification of dengue infection have been documented. Such difficulties could be due to the low awareness of the World Health Organization diagnostic guidelines among clinicians.. To study the diagnostic practices of clinicians in classifying patients as dengue fever (DF) or dengue haemorrhagic fever (DHF)/dengue shock syndrome (DSS) at the time of discharge during an outbreak.. A prospective descriptive study of clinical features and disease classification in adult and pediatric dengue patients in the University of Malaya Medical Centre.. Five hundred and twenty adult and 191 pediatric patients were enrolled. Thrombocytopenia and evidence of plasma leakage were present in 8% of adult and 19% of pediatric patients. Of these, 93% and 49%, respectively, were given the discharge diagnoses of DF instead of DHF/DSS. Hemoconcentration, serous effusion and thrombocytopenia were not recognized in clinicians' discharge diagnosis of DHF/DSS for adult patients. The receiver operating characteristic (ROC) curve suggested a lack of consistency in the use of WHO guidelines in establishing DHF/DSS in adult patients, while implying otherwise for pediatric patients.. DHF/DSS is an under-recognized condition by clinicians managing these patients. This can affect the case fatality rate of DHF/DSS and the economic burden of the disease. The lack of awareness in disease manifestations especially plasma leakage, can lead to delayed recognition of DHF/DSS.

Topics: Academic Medical Centers; Adolescent; Adult; Area Under Curve; Child; Child, Preschool; Dengue; Disease Outbreaks; Humans; Malaysia; Practice Patterns, Physicians'; ROC Curve; Severe Dengue; World Health Organization

Outbreaks involving dengue viruses (DENV) of the same genotype occur in a cyclical pattern in Malaysia. Two cycles of outbreaks involving dengue virus type 2 (DENV-2) of the same genotype occurred in the 1990s in the Klang Valley, Malaysia. Sera of patients from the first outbreak and sera of mice inoculated with virus from the same outbreak had poorer neutralization activity against virus of the second outbreak. Conversely, patient sera from the second outbreak showed higher neutralization titer against virus of the early outbreak. At subneutralizing concentrations, sera of mice immunized with second outbreak virus did not significantly enhance infection with viruses from the earlier outbreak. Amino acid substitution from valine to isoleucine at position 129 of the envelope protein (E), as well as threonine to alanine at position 117 and lysine to arginine at position 272 of the NS1 protein, differentiated viruses of the two outbreaks. These findings highlight the potential influence of specific intragenotypic variations in eliciting varied host immune responses against the different DENV subgenotypes. This could be an important contributing factor in the recurring homogenotypic dengue virus outbreaks seen in dengue-endemic regions.

Topics: Amino Acid Substitution; Animals; Antibodies, Viral; Cross Reactions; Dengue; Dengue Virus; Disease Outbreaks; Humans; Malaysia; Mice; Mutation, Missense; Neutralization Tests; Viral Envelope Proteins; Viral Nonstructural Proteins; Virulence

Topics: Aedes; Animals; Dengue; Humans; Insect Vectors; Malaysia; Population Surveillance; Public Health Administration; Sanitation

The objective of this study was to elucidate the association of various risk factors with dengue cases reported in Lundu district, Sarawak, by analyzing the interaction between environmental, entomological, socio-demographic factors. Besides conventional entomological, serological and house surveys, this study also used GIS technology to generate geographic and environmental data on Aedes albopictus and dengue transmission. Seven villages were chosen based on the high number of dengue cases reported. A total of 551 households were surveyed. An overall description of the socio-demographic background and basic facilities was presented together with entomological and geographical profiles. For serological and ovitrap studies, systematic random sampling was used. Serological tests indicated that 23.7% of the 215 samples had a history of dengue, either recent or previous infections. Two samples (0.9%) were confirmed by IgM ELISA and 49 samples (22.8%) had IgG responses. A total of 32,838 Aedes albopictus eggs were collected in 56 days of trapping. Cluster sampling was also done to determine whether any of the risk factors (entomological or geographical) were influenced by geographical location. These clusters were defined as border villages with East Kalimantan and roadside villages along Lundu/Biawas trunk road. The data collected were analyzed using SPSS version 10.01. Descriptive analysis using frequency, means, and median were used. To determine the association between variables and dengue cases reported, and to describe the differences between the two clusters of villages, two-sample t-test, and Pearson's Chi-Square were used. Accurate maps were produced with overlay and density function, which facilitates the map visualization and report generating phases. This study also highlights the use of differential Global Positioning System in mapping sites of 1m accuracy. Analysis of the data revealed there are significant differences in clusters of villages attributable to container density, house density, distance of the house from the main road, and number of Ae. albopictus eggs from ovitraps set indoor, outdoor and in dumping sites (Person's Chi-Square = 6.111, df = 1, p < 0.01). Further analysis using t-test showed that house density, container density, indoor mosquitoes egg count, outdoor mosquitoes egg count, and dumping sites mosquitoes egg count were higher at the roadside villages compared to border villages. A number of potential risk factors includin

Topics: Aedes; Animals; Antibodies, Viral; Dengue; Disease Outbreaks; Humans; Insect Vectors; Larva; Malaysia; Population Surveillance; Retrospective Studies; Risk Factors; Rural Health

This was a retrospective study of patients with dengue infection in pregnancy from year 2000 till 2004. Data were analyzed by looking at the presentation, complications of patient and fetus, and pregnancy outcomes. There was a total of 16 cases with an increasing trend (0.12% in 2003 vs 0.25% in 2004). The mean age of patients was 30.19+/-6.85 years. Fifty percent of patients were multiparae and in their third trimester. The average gestation was 24.44 weeks with 7.5 days being the average duration of ward admission. Tourniquet test was positive in 62.5% of patients. Dengue serology IgM was positive in 50% whereas dengue serology IgG were positive in 68.8% of patients. There were three cases of maternal death. One patient presented as missed abortion. Preterm deliveries happened in 50.0% of the women. There were 4 premature babies, one in-utero fetal death, and two fetuses which suffered acute fetal distress. Three babies required intensive care. One unrelated fetal anomaly resulted in early neonatal death.

Topics: Adult; Dengue; Female; Fetus; Humans; Immunoglobulin G; Immunoglobulin M; Malaysia; Pregnancy; Pregnancy Outcome; Retrospective Studies

Dengue fever is major public health problem especially among the highly urbanized states of Malaysia, such as, Selangor and Kuala Lumpur Federal Territory. We report an epidemiological cluster pattern of dengue outbreak in the district of Gombak, Selangor that may mimic other acute febrile illnesses in which the transmission mode is via close contact. This dengue outbreak consisted of two waves; an initial cluster of three cases (including the first deceased, JI) which occurred between 20th and 21st of July, followed by a later larger cluster of 11 cases that occurred between 1st and 8th of August 2005. This epidemiological clustering pattern of acute dengue virus infection among close contacts suggests an intense rate of dengue virus transmission within the vicinity of the first deceased's house.

Topics: Adolescent; Adult; Child; Child, Preschool; Cluster Analysis; Dengue; Disease Outbreaks; Female; Humans; Malaysia; Male

Ovitrap surveillance was conducted in four dengue endemic areas in Kuala Lumpur and Selangor, Malaysia to determine the distribution and percentage of mixed breeding of both Aedes aegypti and Aedes albopictus. The percentage of mixed breeding in all study sites both indoors and outdoors accounted for 10 to 32 % from the total ovitraps collected. Ae. aegypti was found at a higher frequency than Ae. albopictus in these ovitraps. This study again indicates that ovitrap is a sensitive tool to attract gravid females of more than one mosquito species to oviposit in the container.

Topics: Aedes; Animals; Breeding; Demography; Dengue; Endemic Diseases; Female; Insect Vectors; Malaysia; Reproduction

Dengue and dengue haemorrhagic fever are common and serious arboviral diseases endemic in a number of countries situated in both the tropical and subtropical belts.. A prospective study was carried out to examine the environmental factors influencing the ovipositing behaviour of gravid female Aedes mosquitoes in a typical urbanised residential environment in Malaysia. This study reports the effect of the usual ultra-low volume fogging of insecticides carried out by public health officers on the collection of immature Aedes mosquitoes using ovitraps.. Throughout the study, no dead immature Aedes mosquitoes was noted in any of the ovitraps set up in all of the fogging and immediate post-fogging periods. The mean number of days of ovitrapping for immediate pre-fogging, fogging and post-fogging periods were 10.3, 10.1 and 10.4 days, respectively. There was no statistically significant difference in the mean duration of ovitrapping cycle among the immediate pre-fogging, fogging and immediate post-fogging periods. The total number of immature Aedes mosquitoes collected in the immediate post-fogging periods was more than the immediate pre-fogging periods, and both were more than the fogging periods. However, there was no statistically significant difference in the total number of immature Aedes mosquitoes collected at various periods. It was not unusual to find dead insects, spiders and even small animals collected in ovitraps or environment in the fogged locality within 48 hours of chemical fogging.. In this study, the usual chemical fogging in natural environment was ineffective in breaking the reproductive lifecycle by eliminating gravid female Aedes mosquitoes.

Topics: Aedes; Age Factors; Animals; Dengue; Female; Humans; Insect Vectors; Insecticides; Malaysia; Mosquito Control; Oviposition; Permethrin; Prospective Studies; Severe Dengue

The insect growth regulator pyriproxyfen was tested against Aedes aegypti at 0.01 and 0.02 mg of active ingredient (AI) per liter of water in 60-liter earthern jars. Both concentrations provided 100% control for 4 months. In additional experiments where 10 liters of water were replaced fortnightly, 100% control was still obtained over 4 months with 0.02 mg AI/liter and greater than 93-100% control was obtained over 4 months with 0.01 mg AI/liter. In less-controlled field-trial conditions, pyriproxyfen at a dosage of 0.02 mg AI/liter provided 100% control for 10 wk against Aedes albopictus even though water was replaced either daily or weekly. Although the activity of pyriproxyfen declines after 10 wk, those tests in the plastic tubs showed much higher levels of sustained residual activity compared to those in the earthern jars. Pyriproxyfen did not have an impact on nontarget organisms.

Topics: Aedes; Animals; Dengue; Insect Vectors; Juvenile Hormones; Larva; Malaysia; Mosquito Control; Pyridines; Time Factors

Dengue fever and dengue hemorrhagic fever have been known to be endemic and reportable diseases in Malaysia since 1971. Major outbreaks occurred in 1973, 1982 and in 1998. For the past few decades until now. many studies have been performed to investigate the importance of these two diseases in Malaysia. A retrospective study was carried out in Hospital Tengku Ampuan Rahimah Klang to find the prevalence of these diseases. The data was collected from the record department of this hospital starting from the year 1999 until 2003 (5 years). A total of 6,577 cases of dengue fever and 857 cases of dengue hemorrhagic fever were reported. From the year 2000 onwards, cases of dengue fever had increased tremendously. However for the year 2001, there was a slight decrease in the reported cases. Most cases occurred in 2003, increasing from 674 in 1999 to 2,813 in 2003. Highest incidence was seen in Malay males more than 12 years of age. However, the cases of dengue hemorrhagic fever declined tremendously throughout the years. Most cases occurred in 1999 with 674 cases, then declining to only one in the year 2001 before it increased to 60 and 72 in the years 2002 and 2003, respectively. Most cases occurred in patients above 12 years old, the majority of which were Malay males.

Topics: Adolescent; Dengue; Disease Outbreaks; Endemic Diseases; Female; Hospitals, Community; Humans; Malaysia; Male; Prevalence; Retrospective Studies; Risk Factors; Severe Dengue

Ovitrap surveillance was conducted in two urban residential areas (Taman Samudera Timur and Taman Samudera Selatan) and in a settlement area (Kampung Banjar), which is located 16 km from Kuala Lumpur city center, Malaysia. In Taman Samudera, dengue cases were reported monthly in 2003/2004. Thus, a study was initiated to determine the distribution and abundance of dengue vectors, Aedes aegypti and Ae. albopictus. The ovitrap surveillance indicated that Ae. aegypti and Ae. albopictus were present both indoors and outdoors. The residential sites had 73 - 79% of the ovitraps with just Ae. aegypti population and Kg. Banjar had 56% of the ovitraps with just Ae. aegypti. In the indoor and outdoor of the residential areas, together with the settlement area, the Ae. aegypti density was significantly more than Ae. albopictus (p < 0.05) by 3 - 50 folds. There was no significant difference in the larval numbers of Ae. aegypti between indoors and outdoors (p > 0.05), thus implicating that adult gravid female Ae. aegypti are present both indoors and outdoors and they do oviposit indoors and outdoors. Ae. aegypti can be incriminated as the principal dengue vector in the urban residential site, Taman Samudera and in the settlement area, Kg. Banjar.

Topics: Aedes; Animals; Dengue; Housing; Humans; Insect Vectors; Malaysia; Mosquito Control; Population Density; Seasons; Urban Health

Field bioefficacy of residual-sprayed deltamethrin against Aedes vectors was evaluated in an urban residential area in Kuala Lumpur. The trial area consisted of single storey wood-brick houses and a block of flat. The houses were treated with outdoor residual spraying while the flat was used as an untreated control. Initial pre-survey using ovitrap surveillance indicated high Aedes population in the area. Deltamethrin WG was sprayed at a dosage of 25mg/m2 using a compression sprayer. The effectiveness of deltamethrin was determined by wall bioassay and ovitrap surveillance. The residual activity of 25mg/m2 deltamethrin was still effective for 6 weeks after treatment, based on biweekly bioassay results. Bioassay also indicated that both Aedes aegypti and Aedes albopictus were more susceptible on the wooden surfaces than on brick. Aedes aegypti was more susceptible than Ae. albopictus against deltamethrin. Residual spraying of deltamethrin was not very effective against Aedes in this study since the Aedes population in the study area did not reduce as indicated by the total number of larvae collected using the ovitrap (Wilcoxon Sign Test, p> 0.05). Further studies are required to improve the effectiveness of residual spraying against Aedes vectors.

Topics: Aedes; Animals; Dengue; Environmental Monitoring; Housing; Insect Vectors; Insecticides; Larva; Malaysia; Mosquito Control; Nitriles; Population Density; Program Evaluation; Pyrethrins; Urban Health

Larvae of Aedes aegypti and Aedes albopictus obtained from 6 consecutive ovitrap surveillance (OS) in Taman Samudera and Kg. Banjar were evaluated for their susceptibility to temephos. Larval bioassays were carried out in accordance with WHO standard methods, with diagnostic dosage (0.012 mg/L) and operational dosage (1 mg/L) of temephos respectively. Aedes aegypti and Ae. albopictus obtained from six OS in Taman Samudera showed resistance to diagnostic dosage of temephos with percentage mortality between 5.3 to 72.0 and 9.3 to 56.0, respectively, while Ae. aegypti and Ae. albopictus obtained from Kg. Banjar showed resistance to temephos with percentage mortality between 16.0 to 72.0 and 0 to 50.6, respectively. Only two strains of Ae. aegypti from Kg. Banjar were susceptible to temephos with 93.3% (OS 2) and 100% (OS 3) mortality. The 50% mortality at lethal time (LT50) for all strains of Ae. aegypti and Ae. albopictus tested against operational dosage of temephos showed range between 36.07 to 75.69 minutes and 58.65 to 112.50 minutes, respectively, and complete mortality was achieved after 24 hours. Our results indicated that there is weekly variations of the resistance status for Ae. aegypti and Ae. albopictus. Aedes susceptibility to temephos is changing from time to time in these two study sites. It is essential to continue monitoring the resistance of this vector to insecticides in order to ensure the efficiency of program aimed at vector control and protection of human health.

Topics: Aedes; Animals; Biological Assay; Dengue; Humans; Insect Vectors; Insecticide Resistance; Insecticides; Larva; Malaysia; Temefos

Topics: Asia; Dengue; Humans; Malaysia; Population Surveillance; World Health Organization

Topics: Adolescent; Adult; Aged; Antibodies, Viral; Child; Child, Preschool; Dengue; Dengue Virus; Female; Humans; Malaysia; Male; Middle Aged; Suburban Population

A cross-sectional survey was conducted to assess the level of knowledge, attitude and practices concerning dengue and its vector Aedes mosquito among selected rural communities in the Kuala Kangsar district from 16-25th June, 2002. It was found that the knowledge of the community was good. Out of the 200 respondents, 82.0% cited that their main source of information on dengue was from television/radio. The respondents' attitude was found to be good and most of them were supportive of Aedes control measures. There is a significant association found between knowledge of dengue and attitude towards Aedes control (p = 0.047). It was also found that good knowledge does not necessarily lead to good practice. This is most likely due to certain practices like water storage for domestic use, which is deeply ingrained in the community. Mass media is an important means of conveying health messages to the public even among the rural population, thus research and development of educational strategies designed to improve behaviour and practice of effective control measures among the villagers are recommended.

Topics: Adult; Aedes; Animals; Bites and Stings; Cross-Sectional Studies; Dengue; Dengue Virus; Family Characteristics; Female; Health Education; Health Knowledge, Attitudes, Practice; Humans; Malaysia; Male; Mass Media; Middle Aged; Rural Health; Social Marketing; Socioeconomic Factors; Water Supply

Phylogenetic analyses of the envelope (E) gene sequence of five recently isolated dengue virus type 4 (DENV-4) suggested the emergence of a distinct geographical and temporal DENV-4 subgenotype IIA in Malaysia. Four of the isolates had direct ancestral lineage with DENV-4 Indonesia 1973 and showed evidence of intra-serotypic recombination with the other recently isolated DENV-4, MY01-22713. The E gene of isolate MY01-22713 had strong evidence of an earlier recombination involving DENV-4 genotype II Indonesia 1976 and genotype I Malaysia 1969. These results suggest that intra-serotypic recombination amongst DENV-4 from independent ancestral lineages may have contributed to the emergence of DENV-4 subgenotype IIA in Malaysia.

Topics: Aedes; Animals; Base Sequence; Cell Line; Dengue; Dengue Virus; DNA, Viral; Genotype; Humans; Malaysia; Molecular Sequence Data; Mutagenesis; Phylogeny; Sequence Analysis, DNA; Viral Envelope Proteins

Dengue continues to be a major health threat to Malaysia a century after its first reported outbreak in 1902. Examination of the available outbreak data suggested that a major DF/DHF outbreak occurred in Malaysia in a cyclical pattern of approximately every 8 years. All four dengue virus serotypes are found co-circulating in Malaysia, but after the first and only major outbreak involving DEN-4 in 1960's, only DEN-1, DEN-2 and DEN-3 were associated with DF/DHF outbreaks. It is argued that perhaps the spread of the later dengue virus serotypes followed the pattern of spread of the mosquito vector Aedes aegypti, whereas the former was associated with Aedes albopictus, the outdoor and rural area dwelling mosquito. Estimating from the trend and pattern of dengue and the associated dengue virus serotypes, unless there is a major breakthrough in dengue vaccine development, it is likely that dengue outbreaks will continue to occur in Malaysia throughout the 21st century.

Topics: Aedes; Animals; Dengue; Dengue Virus; Disease Outbreaks; Humans; Insect Vectors; Malaysia; Serotyping

Deltacide (S-bioallethrin 0.71% w/v, deltamethrin 0.5% w/v, piperonyl butoxide 8.9% w/v excipients to 100% w/v) and Solfac UL 015 (cyfluthrin 1.5% w/v) were evaluated against the sentinel sugar-fed adults and 4th-instar larvae of Aedes aegypti at 17 storey high-rise apartments in Malaysia using ULV applications. The impact of both insecticides on field populations of Ae. aegypti and Ae. albopictus larvae was monitored weekly using bottle containers. Both Deltacide and Solfac UL 015 showed adulticidal and larvicidal effects. This was the first field trial using Deltacide against dengue vectors in Malaysia and showed its potential for use in dengue vector control programs.

Topics: Aedes; Allethrins; Animals; Dengue; Humans; Insect Vectors; Insecticides; Larva; Malaysia; Nitriles; Pest Control; Piperonyl Butoxide; Pyrethrins

Topics: Adolescent; Adult; Age Distribution; Dengue; Humans; Incidence; Malaysia; Middle Aged; Severe Dengue; Survival Rate

Cyfluthrin (Solfac ULO15) and malathion 96 TG were evaluated against sentinel sugar-fed adults and 4th-instar larvae of Aedes aegypti at high-rise flats in Malaysia by ULV spraying. The impact of both insecticides on field populations of Aedes spp. (Ae. aegypti and Ae. albopictus) larvae were monitored weekly using containers. Both cyfluthrin and malathion 96 TG showed adulticidal effects but cyfluthrin showed more significant larvicidal effect than malathion 96 TG (P < 0.05).

Topics: Animals; Dengue; Housing; Humans; Insect Vectors; Insecticides; Larva; Malathion; Malaysia; Mosquito Control; Nitriles; Pyrethrins

Topics: Aedes; Animals; Dengue; Dengue Virus; Female; Immunoenzyme Techniques; Malaysia; Male; Oviposition; Ovum; Polymerase Chain Reaction; Species Specificity

Since dengue was first documented in Malaysia in 1902 and made notifiable in 1973, the disease pattern has changed from major outbreaks every four years to one of increasing trend yearly. The largest outbreak was seen in 1996 with 14,255 dengue cases reported and 32 deaths. The case fatality rate varied from a high of 10.43% in 1985 when dengue type 3 was the predominant type to a low of 1.29% when dengue type 1 predominated. Severe disease patterns have been observed with dengue 2 and 3 serotypes in the country. The clinical spectrum has also been changing and multisystem involvement with more severe manifestations are being seen. Liver involvement has been documented since 1987. Fulminant hepatitis with encephalopathy can resemble Reye's syndrome. Dengue type 3 has been isolated from liver biopsy specimens. Neurological manifestations can very from irritability, convulsions, coma to peripheral neuritis. The isolation of dengue viruses from cerebrospinal fluids recently strongly suggests that dengue viruses can be neurovirulent. Adult respiratory distress syndrome was seen in three children admitted with shock. Deaths were more frequent in children in the early period but since 1982, over 50% of deaths have occurred in patients over the age of 15 years.

Topics: Adult; Child; Dengue; Disease Outbreaks; Humans; Malaysia

Topics: Aedes; Animals; Dengue; Dengue Virus; Disease Susceptibility; Feeding Behavior; Humans; Insect Vectors; Insecticides; Malathion; Malaysia; Mosquito Control

The relationship between the Breteau index, the House index, and the occurrence of dengue/dengue hemorrhagic fever in the 6 zones of Kuala Lumpur was studied throughout 1994. Cases of dengue/dengue hemorrhagic fever varied between zones and between months, ranging from 0 to 21 cases. In most of the zones in Kuala Lumpur, the occurrence of dengue/dengue hemorrhagic fever has no relationship with the Breteau and House indices. Cases of dengue/dengue hemorrhagic fever occurred in all zones despite the low Breteau and House indices.

Topics: Aedes; Animals; Dengue; Insect Vectors; Malaysia; Seasons

Topics: Adolescent; Adult; Child; Child, Preschool; Cross-Sectional Studies; Dengue; Developing Countries; Female; Humans; Incidence; Infant; Malaysia; Male; Serotyping; Survival Rate

This study describes the use of polymerase chain reaction as a diagnostic tool for detecting and typing of dengue virus. PCR was compared against virus isolation. First RT-PCR was done using dengue consensus primers after which positive samples were subjected to RT-PCR using type-specific primers. This study shows that the local strains of the dengue virus could be detected using the chosen primers. Furthermore, RT-PCR was found to be more sensitive than virus isolation in identifying the dengue positive samples.

Topics: Case-Control Studies; Dengue; Dengue Virus; Humans; Malaysia; Random Amplified Polymorphic DNA Technique; Reproducibility of Results; RNA, Viral; Sensitivity and Specificity; Serotyping

Topics: Dengue; Humans; Malaysia

Topics: Adolescent; Adult; Child; Child, Preschool; Dengue; Female; Health Education; Humans; Malaysia; Male; Mosquito Control; Seasons

Topics: Adolescent; Adult; Child; Child, Preschool; Community Participation; Dengue; Female; Health Education; Humans; Incidence; Insect Control; Malaysia; Male

The control of dengue outbreak requires a multi-pronged effort by the various government agencies. It requires co-operation of the community in the control activities, strict adherence to existing control procedures and guidelines by health personnel, increased manpower where necessary and strengthening co-operation between various health agencies to prevent delay in instituting control measures.

Topics: Communicable Disease Control; Dengue; Disease Outbreaks; Humans; Malaysia

Dengue fever/Dengue haemorrhagic fever (DF/DHF) has been a public health problem in Malaysia with an endemic level of about 7 per 100,000 population per year. In 1990, Malaysia experienced its most severe outbreak of DF/DHF with a record total of 5,590 cases referred to the Division of Virology, Institute for Medical Research (IMR). Of these, 1,880 were confirmed serologically to be DF/DHF. The conventional serological procedure, the Haemagglutination Inhibition (HI) test, for the diagnosis of DF/DHF is cumbersome and causes delay in diagnosis. Another problem associated with the HI test has been that it has often been difficult to obtain a second convalescent serum sample for an accurate diagnosis. This has raised an urgent need to establish a "rapid" test for diagnosis of DF/DHF. As such the authors recently carried out an evaluation of a newly available commercial rapid test, namely, the Dengue Blot Assay (Diagnostic Biotechnology Singapore Pte Ltd). The test is intended for use in laboratory confirmation of dengue virus infection. The evaluation was to determine if the test could be utilised as a routine laboratory test and to establish its sensitivity and specificity. Over 400 samples were tested against the Dengue Blot Assay. Results were checked against an in-house Dengue IgM ELISA and HI assay. Preliminary results indicate that the sensitivity and specificity of the Dengue Blot is satisfactory. Our results also indicate that the Dengue Blot has a useful role to play in a routine laboratory especially since it provides rapid results on single serum samples thereby reducing the workload in a busy diagnostic laboratory.

Topics: Dengue; Dengue Virus; Enzyme-Linked Immunosorbent Assay; Hemagglutination Inhibition Tests; Humans; Malaysia; Reagent Kits, Diagnostic

This study describes the status of viral encephalitis in Perak, Malaysia during the year 1990. In addition, 14 cases selected from Penang and Perak during the years 1989 and 1990 are presented, with data showing titers of neutralizing antibodies against Japanese encephalitis virus (JEV) and dengue 2 virus, titers of antibodies against JEV and dengue virus antigens as determined by DEIA, and a comparison of these with the presence of IgM to JEV and dengue virus. These data show that there probably is far more viral encephalitis due to JEV in Malaysia than the national figures reflect.

Topics: Adolescent; Adult; Child; Child, Preschool; Dengue; Encephalitis, Japanese; Enzyme-Linked Immunosorbent Assay; Female; Humans; Immunoblotting; Immunoenzyme Techniques; Immunoglobulin M; Incidence; Malaysia; Male; Neutralization Tests; Seasons; Seroepidemiologic Studies

This study describes the use of an IgM capture ELISA using cell culture derived antigens and a polyclonal rabbit antiflavivirus antisera for the detection of dengue positive cases. The IgM capture ELISA is compared with the dot enzyme immunoassay and the results are discussed in the context of dengue endemicity.

Topics: Dengue; Enzyme-Linked Immunosorbent Assay; Evaluation Studies as Topic; Humans; Immunoblotting; Immunoenzyme Techniques; Immunoglobulin M; Malaysia; Recurrence; Sensitivity and Specificity; Serotyping

Field trials were conducted in two residential areas of Petaling Jaya Municipality to test the adulticidal and larvicidal effects of malathion 96% TG and Resigen on Aedes aegypti. Malathion is the currently used insecticide in Malaysia for the control of dengue. The Leco HD ULV machine was used throught the trials. For malathion the flow rate was 90 ml/minute at a vehicle speed of 8kph and for Resigen the flow rate was 200 ml/minute at the same vechicle speed. Malathion was more effective giving higher mortality rates when compared with Resigen. The mortality rate of adult Ae. aegypti outdoor was higher than in the living room and kitchen. Both insecticides did not show promising larvicidal effects.

Topics: Aedes; Allethrins; Animals; Dengue; Humans; Malathion; Malaysia; Mosquito Control; Piperonyl Butoxide; Pyrethrins

Topics: Adult; Aged; Dengue; Female; Humans; Malaysia; Male; Pakistan; Travel; United Kingdom

Topics: Base Sequence; Capsid; Dengue; Dengue Virus; Humans; Malaysia; Molecular Sequence Data; Sequence Homology, Nucleic Acid; Syndrome; Viral Core Proteins; Viral Nonstructural Proteins

Topics: Amino Acid Sequence; Base Sequence; Capsid; Dengue; Dengue Virus; Genes, Viral; Humans; Malaysia; Molecular Sequence Data; Sequence Homology, Nucleic Acid; Shock, Septic; Viral Structural Proteins

Topics: Amino Acid Sequence; Base Sequence; Dengue; Dengue Virus; Genes, Viral; Humans; Malaysia; Molecular Sequence Data; Protein Precursors; Sequence Homology, Nucleic Acid; Shock, Septic; Viral Matrix Proteins; Viral Structural Proteins

Thirteen strains of dengue type 1 were isolated from the lymphocyte fractions of 69 acute phase blood samples collected at Thursday Island Hospital during 1981 and 1982. One further strain of type 1 was isolated from 7 blood samples despatched by air from Cairns Base Hospital during 1982. Four of these Australian isolates representing the beginning, middle, and end of the epidemic were examined by restriction enzyme mapping and were found to be identical for the nine restriction enzymes used. The maps differed from those derived from two Malaysian dengue type 1 strains isolated during the epidemic of 1981-82 in that country. This suggests reliance on serological typing to establish global circulation patterns of epidemic dengue is insufficient and that more specific methods such as genome mapping are useful.

Topics: Adolescent; Adult; Child; Dengue; Dengue Virus; Disease Outbreaks; DNA Restriction Enzymes; Female; Humans; Infant; Lymphocytes; Malaysia; Male; Nucleic Acid Hybridization; Queensland; RNA, Viral; Serotyping

Topics: Adolescent; Child; Child, Preschool; Dengue; Epidemiologic Methods; Humans; Infant; Malaysia

Four recent cases of dengue fever with severe, unusual clinical manifestations are described. Two of these cases had features of fulminant hepatitis and encephalopathy; one of these cases was fatal. The two remaining cases showed hepatitis with renal impairment. The significance and importance of these unusual manifestations of dengue disease are discussed.

Topics: Adolescent; Adult; Central Nervous System; Child; Dengue; Female; Hepatitis; Humans; Infant; Kidney; Malaysia; Male

Biotechnological tools are being used in malaria, filariasis and dengue research. The main emphasis has been on the production of reagents for immunodiagnosis and research. In this respect monoclonal antibodies (McAbs) against various species and stages of the above pathogens have been produced. It is hoped that these McAbs will be useful not only in immunodiagnosis but also for seroepidemiological applications. A DNA probe against Brugia malayi has been tested in Malaysia and was found to be sensitive and specific.

Topics: Animals; Antibodies, Monoclonal; Biotechnology; Brugia; Dengue; DNA, Recombinant; Elephantiasis, Filarial; Filariasis; Humans; Malaria; Malaysia; Parasitic Diseases

Acute-phase serum samples collected during an outbreak of dengue fever and dengue haemorrhagic fever in Penang, Malaysia, were tested by a method involving antibody-dependent enhancement of infectivity in the mouse macrophage-like cell line, P388D1. 58 of 71 (81.7%) serologically positive cases yielded virus.

Topics: Animals; Antibodies, Viral; Dengue; Dengue Virus; Disease Outbreaks; Humans; Macrophages; Malaysia; Methods; Mice

A case of haemorrhagic fever with renal syndrome that originated in Malaysia is reported. The patient presented with clinical symptoms which were not typical of the disease as seen in endemic regions. Renal involvement, which is characteristic of haemorrhagic fever with renal syndrome, was mild, and the predominant symptom was a persistently marked elevation of serum transaminase levels that was suggestive of hepatitis. Liver involvement has not been described in the Asian form of haemorrhagic fever with renal syndrome. The patient developed a petechial skin rash and had severe thrombocytopenia. Serological confirmation of the diagnosis of haemorrhagic fever with renal syndrome was obtained by the demonstration of significant antibody rises to hantaviruses in the patient's acute- and convalescent-phase sera.

Topics: Adult; Antibodies, Viral; Dengue; Diagnosis, Differential; Hemorrhagic Fever with Renal Syndrome; Hepatitis, Viral, Human; Humans; Malaysia; Male; Orthohantavirus; Vietnam

A nation-wide outbreak of 260 cases of DF/DHF with 1 death occurred in Singapore from Apr-Sept 1986. The outbreak originated from 3 separate foci of transmission at the western, south-eastern and north-eastern parts of the island and then spread to other dengue receptive urban and suburban areas. The morbidity rate was highest in young male Chinese adults between 15 and 24 years of age. The outbreak was rapidly brought under control through destruction of adult Aedes mosquitoes, surveys and source reduction of larval breeding habitats, health education and to a certain extent law enforcement. The Aedes population was high in the main foci of transmission although the overall house index was only 1.1. Other factors which could have precipitated the outbreak included waning herd immunity of the human population and continuous introduction of dengue virus into the country.

Topics: Aedes; Animals; China; Dengue; Disease Outbreaks; Ethnicity; Female; Humans; India; Malaysia; Male; Mosquito Control; Singapore

A serological study on dengue infection conducted in Singapore during the period 1982 to 1984 showed that 54.4% of the healthy population between 6 months and over 50 years of age surveyed possessed no haemagglutination-inhibition antibody to dengue type 2 virus. Children below 10 years of age showed the lowest antibody prevalence and were at the greatest risk, with 96.6% susceptible to infection, whereas virtually all adults over 40 showed evidence of prior dengue infection. The geometric mean titre showed a rising trend indicating continuing acquisition of infection in the older age groups. The seropositivity rate of dengue infection of males was twice that of females. Among the 3 major ethnic groups, no significant difference in seropositivity was noted between the Malays and Indians, but the differences between Malays and Chinese and between Indians and Chinese were statistically significant. The study confirmed that the successful implementation of the nation-wide Aedes control programme is reducing endemic dengue virus transmission in the country.

Topics: Adolescent; Adult; Antibodies, Viral; Child; Child, Preschool; China; Dengue; Dengue Virus; Female; Humans; India; Infant; Malaysia; Male; Middle Aged; Sex Factors; Singapore

Topics: Adolescent; Adult; Aedes; Animals; Child; Child, Preschool; Dengue; Disease Outbreaks; Female; Humans; Infant; Infant, Newborn; Insect Vectors; Malaysia; Male; Middle Aged; Mosquito Control

Topics: Adult; Aedes; Attitude to Health; Dengue; Humans; Malaysia

An epidemio-meteorotropic analytical study of Selangor, in the Southwest coast of Peninsular Malaysia, examines the monthly incidence of dengue for the period 1973-1982 to assess possible quantitative association with the monthly rainfall. The relationships between rainfall, abundance of A. aegypti and dengue infection during 1982 in Jinjang, a dengue-prone area in Selangor, were also examined. A quantitative association between rainfall and the number of dengue cases was found during the first wet period. The lag time between the onset of heavy rain and dengue outbreak was about two to three months. A 120% increase in the number of dengue cases was observed when the monthly rainfall was 300 mm or more. Positive associations were seen between the incidence of dengue and the Aedes house index and the Breteau index in Jinjang. The relationships between these three variables and rainfall suggest that the latter might have exerted its effect on dengue infection partly through the creation of more breeding sites for A. aegypti. Assessment of the importance of A. aegypti in the transmission of dengue in this locality was not possible because of the lack of adjustment for A. albopictus, the other known vector of dengue in the state, and for social and other environmental factors influencing infection rates. In spite of this and the interpretational problems common in aggregate studies, the present analyses have provided relatively strong statistical evidence of an association between rainfall and dengue outbreaks in Selangor, thereby indicating that it is a factor worthy of careful surveillance and monitoring.

Topics: Aedes; Animals; Dengue; Disease Outbreaks; Humans; Insect Vectors; Malaysia; Rain; Seasons; Weather

In 1982, Malaysia experienced the worst dengue/dengue haemorrhagic fever outbreak in its history. All states in Peninsular and East Malaysia were similarly affected. There was a total of 3,005 cases with 35 deaths, with the majority of cases occurring between the months of July to October. There was a total of 1,001 laboratory confirmed cases. Most of the cases were in patients over the age of 15 years. The Chinese population was mainly affected, although a much higher proportion of Malays was noted in comparison to previous years. The main serotypes involved were dengue-1 and dengue-3. No dengue-4 serotype were isolated.

Topics: Adolescent; Adult; Child; Child, Preschool; Dengue; Dengue Virus; Disease Outbreaks; Female; Humans; Infant; Infant, Newborn; Malaysia; Male; Seasons; Serotyping

Analysis of the bleeding manifestations of 130 cases of dengue haemorrhagic fever admitted into the Children's ward of the General Hospital, Kuala Lumpur from May 1973 to September 1978 has been done. Petechial skin rash, epistaxis and gum bleeding were seen most commonly in mild and moderately severe cases. However, blood stained gastric aspirates, and severe haematemesis were seen in severe or very severe cases. Though with better vector control and preventive measures, a marked reduction in the incidence of the cases has been noted, severe cases were seen with symptoms of shock and gastrointestinal bleeding. These symptoms carried a bad prognosis. Among 15 children that died 10 had gastrointestinal bleeding and 2 had a disseminated intravascular coagulation defect. Lymphocytosis with atypical lymphocytes, low platelet count, low reticulocyte count and raised packed cell volume were the main haematological features seen in all these cases. All these features reverted to normal within a week. Mild evidence of disseminated intravascular coagulation was seen in a number of cases, but severe features were seen only in four. Two cases improved as a result of heparin therapy.

Topics: Age Factors; Child; Child, Preschool; Dengue; Female; Hemorrhage; Humans; Infant; Malaysia; Male; Racial Groups; Seasons

Topics: Aedes; Animals; Dengue; Disease Outbreaks; Insect Vectors; Malaysia

The first major Malaysian epidemic of dengue hemorrhagic fever with severe manifestations occurred in 1973, with 969 reported cases and 54 deaths. In a detailed study of 138 clinically diagnosed and laboratory confirmed cases at the General Hospital in Kuala Lumpur, hemorrhagic manifestations were observed in 68.7% and shock in 18.1% of the patients. The cases occurred mainly from May to September, largely in urban and suburban areas of the majority of the states in the country. A main focus of infection was Jinjang, a heavily populated outlying district of Kuala Lumpur, where unusually high incidences of morbidity, severe disease and mortality were seen. Severe disease was seen mostly in children under the age of 15 years, although a significant number of adults suffered milder illnesses. The Chinese population was chiefly affected, due to their living in crowded, low-income housing where the vector, Aedes aegypti, occurred in the greatest numbers. All four dengue types were recovered during the epidemic period, although dengue 3 (DEN-3) was incriminated as the major epidemic type. Entomological data revealed high indices of A. aegypti throughout the country and left little doubt that this epidemic was aegypti transmitted. Spraying and fogging operations were carried out in attempts to control vector populations.

Topics: Adolescent; Adult; Age Factors; Antibodies, Viral; Child; Child, Preschool; Culicidae; Dengue; Dengue Virus; Disease Outbreaks; Ethnicity; Female; Hemagglutination Inhibition Tests; Humans; Infant; Insect Vectors; Malaysia; Male; Sex Factors

Topics: Aedes; Animals; Dengue; Humans; Malaysia; Rain; Seasons; Water Supply; Weather

Topics: Aedes; Animals; Culicidae; Dengue; Humans; Malaysia; Urban Health

Topics: Aedes; Animals; Dengue; Ecology; Female; Humans; Insect Vectors; Malaysia; Male; Species Specificity; Zoonoses

Topics: Aedes; Animals; Communicable Disease Control; Community Health Workers; Dengue; Disease Vectors; Health Knowledge, Attitudes, Practice; Humans; Insect Bites and Stings; Insect Control; Insect Vectors; Malaysia; Public Opinion; Urban Population

An ovitrap survey was carried out in April and May of 1975 at twenty-one locations scattered throughout Penang Island excluding the City of Georgetown. The results showed the ubiquitous presence of Ae. albopictus. Ae. aegypti was recorded only in Tanjung Tokong Lama, an area adjacent to the City of Georgetown. In the survey, Ae. albopictus females were found to prefer the outdoor ovitraps than indoor ones. The effectiveness of ovitrap in Aedes survey was discussed.

Topics: Aedes; Animals; Dengue; Ecology; Female; Geography; Malaysia; Male; Oviposition; Ovum; Rural Health

Topics: Age Factors; China; Dengue; Female; Humans; Malaysia; Male; Urban Population

Topics: Aedes; Dengue; Hemorrhagic Fevers, Viral; Humans; Insect Vectors; Malaysia

Topics: Aedes; Animals; Culex; Dengue; Disease Reservoirs; Malaysia; Species Specificity

Topics: Animals; Culicidae; Dengue; Gastrointestinal Hemorrhage; Humans; Malaysia; Zoonoses

Topics: Aedes; Animals; Arbovirus Infections; Classification; Culicidae; Dengue; Diagnosis; Hemoglobins; Hemorrhagic Fever with Renal Syndrome; Hemorrhagic Fevers, Viral; Humans; Insect Vectors; Leukocyte Count; Malaysia; Mortality; Statistics as Topic

Topics: Animals; Dengue; Ecology; In Vitro Techniques; Malaysia; Zoonoses

In order to obtain information on the occurrence of arboviruses in Western Australia, sera from white persons and Australian aborigines and from animals were subjected to antibody estimations with selected viruses as a prelude to virus isolations. The serological evidence shows the presence of group A and group B arboviruses but significant differences in antibody distribution between the two groups. Antibodies to group A viruses, particularly to the Malayan mosquito virus AMM 2354, are present in both the aboriginal and the white populations over the entire territory. Neutralizing antibody to another group A virus, AMM 2021, isolated in Malaya, is found in much lower prevalence, while antibodies to the newly isolated Queensland group A virus, MRM 39, are found only in the Kimberley area. No avian group A antibodies were detected. The prevalence of group B antibodies is high in the northern part of the State and almost non-existent in the central areas. The results indicate the presence of more than one group B virus and the absence of dengue neutralizing antibody in the Australian aborigine. A unique situation exists in central Australia, where all aboriginal sera have group A antibody but none has group B antibody.

Topics: Allergy and Immunology; Animals; Antibodies; Arbovirus Infections; Arboviruses; Australia; Birds; Culicidae; Dengue; Epidemiology; Flavivirus; Malaysia; Western Australia

Topics: Animals; Culicidae; Dengue; Encephalitis; Encephalitis, Japanese; Humans; Malaysia; Rural Population; Yellow Fever

Topics: Animals; Culicidae; Dengue; Dengue Virus; Disease Outbreaks; Malaysia