exudates and Malaria--Vivax

Anemia is a major complication of vivax malaria. Antiphosphatidylserine (PS) antibodies generated during falciparum malaria mediate phagocytosis of uninfected red blood cells that expose PS and have been linked to late malarial anemia. However, their role in anemia from non-falciparum Plasmodium species is not known, nor their role in early anemia from falciparum malaria.. We measured PS immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies in Malaysian patients with vivax, falciparum, knowlesi, and malariae malaria, and in healthy controls, and correlated antibody titres with hemoglobin. PS antibodies were also measured in volunteers experimentally infected with Plasmodium vivax and Plasmodium falciparum.. PS IgM and IgG antibodies were elevated in patients with vivax, falciparum, knowlesi, and malariae malaria (P < .0001 for all comparisons with controls) and were highest in vivax malaria. In vivax and falciparum malaria, PS IgM and IgG on admission correlated inversely with admission and nadir hemoglobin, controlling for parasitemia and fever duration. PS IgM and IgG were also increased in volunteers infected with blood-stage P. vivax and P. falciparum, and were higher in P. vivax infection.. PS antibodies are higher in vivax than falciparum malaria, correlate inversely with hemoglobin, and may contribute to the early loss of uninfected red blood cells found in malarial anemia from both species.

Topics: Adolescent; Adult; Anemia; Antibodies, Antiphospholipid; Female; Hemoglobins; Humans; Immunoglobulin G; Immunoglobulin M; Malaria, Falciparum; Malaria, Vivax; Malaysia; Male; Young Adult

The zoonotic Plasmodium knowlesi parasite is a growing public health concern in Southeast Asia, especially in Malaysia, where elimination of P. falciparum and P. vivax malaria has been the focus of control efforts. Understanding of the genetic diversity of P. knowlesi parasites can provide insights into its evolution, population structure, diagnostics, transmission dynamics, and the emergence of drug resistance. Previous work has revealed that P. knowlesi fall into three main sub-populations distinguished by a combination of geographical location and macaque host (Macaca fascicularis and M. nemestrina). It has been shown that Malaysian Borneo groups display profound heterogeneity with long regions of high or low divergence resulting in mosaic patterns between sub-populations, with some evidence of chromosomal-segment exchanges. However, the genetic structure of non-Borneo sub-populations is less clear. By gathering one of the largest collections of P. knowlesi whole-genome sequencing data, we studied structural genomic changes across sub-populations, with the analysis revealing differences in Borneo clusters linked to mosquito-related stages of the parasite cycle, in contrast to differences in host-related stages for the Peninsular group. Our work identifies new genetic exchange events, including introgressions between Malaysian Peninsular and M. nemestrina-associated clusters on various chromosomes, including in parasite invasion genes (DBP[Formula: see text], NBPX[Formula: see text] and NBPX[Formula: see text]), and important proteins expressed in the vertebrate parasite stages. Recombination events appear to have occurred between the Peninsular and M. fascicularis-associated groups, including in the DBP[Formula: see text] and DBP[Formula: see text] invasion associated genes. Overall, our work finds that genetic exchange events have occurred among the recognised contemporary groups of P. knowlesi parasites during their evolutionary history, leading to apparent mosaicism between these sub-populations. These findings generate new hypotheses relevant to parasite evolutionary biology and P. knowlesi epidemiology, which can inform malaria control approaches to containing the impact of zoonotic malaria on human communities.

Topics: Animals; Genetic Variation; Genetics, Population; Humans; Macaca fascicularis; Malaria; Malaria, Falciparum; Malaria, Vivax; Malaysia; Plasmodium knowlesi; Selection, Genetic

Malaysia has achieved the status of zero indigenous human malaria cases. Nevertheless, imported human malaria has increasingly been reported in Sarawak, Malaysian Borneo. As zoonotic malaria caused by Plasmodium knowlesi remains a major public health problem in Sarawak, the threat of imported malaria must be addressed as it can cause human malaria reintroduction, sustain transmission, and lead to complications. The objectives of this study were to investigate the epidemiological characteristics of imported malaria cases reported in Sarawak and to underline the challenge posed by imported malaria towards malaria elimination efforts.. Imported malaria cases reported in Sarawak from 2011 to 2019 were collected from Sarawak State Health Department and analysed in this longitudinal retrospective study.. A total of 2058 imported malaria cases were registered in all districts in Sarawak. Highest number of cases were reported in Kapit (n = 559; 27.16%), followed by Sibu (n = 424; 20.6%), and Miri (n = 166; 8.07%). Based on the demographic profile, most of the patients constituted of either male sex (98.49%), age group of 40-49 years (39.6%), Iban ethnic (57.92%), worked in logging industry (88.58%), Malaysian nationals (91.84%), contracted malaria in Papua New Guinea (46.11%), uncomplicated disease (77.89%), or hospitalised cases (97.86%). The most prominent Plasmodium species diagnosed were P. vivax (52.67%) and P. falciparum (35.81%).. Surveillance, disease detection, and medical follow-up must be carried out thoroughly for individuals who returned from malaria-endemic countries. It is also necessary to promote pre-travel preventive education as well as chemoprophylaxis to travellers heading to endemic areas.

Topics: Adult; Humans; Malaria; Malaria, Falciparum; Malaria, Vivax; Malaysia; Male; Middle Aged; Plasmodium knowlesi; Retrospective Studies

The treatment of Plasmodium vivax malaria with 8-aminoquinolines is contraindicated in glucose-6-phosphate dehydrogenase (G6PD) deficient individuals due to the risk of acute haemolytic anaemia. Effective G6PD screening is paramount to avoid adverse drug reactions. This study aimed to evaluate the performance of novel quantitative point-of-care (POC) tests as a new screening method for G6PD deficiency in Malaysia.. A total of 153 neonatal cord blood, 99 peripheral blood of older children aged between 1 month to 12-years old, and 62 peripheral adult blood were screened for G6PD deficiency using two quantitative POC tests, CareStartTM biosensor (Carestart) and CareStartTM Biosensor 1 (S1). The results were compared with OSMMR2000D kit as a reference assay. Two statistical analyses were performed in this study to evaluate the POC test performances, the Spearman's correlation test and the Cohen's kappa method.. Both Carestart and S1 tests showed significant positive correlations to OSMMRS000D with r. This study showed that the Carestart and S1 biosensors have high-performance reliability for screening of G6PD deficiency, which can guide safe prescriptions of anti-malaria medications and hence, eradication of Plasmodium vivax malaria.

Topics: Adolescent; Adult; Child; Glucosephosphate Dehydrogenase; Glucosephosphate Dehydrogenase Deficiency; Humans; Infant; Infant, Newborn; Malaria, Vivax; Malaysia; Point-of-Care Testing; Reproducibility of Results

Malaria remains a public health problem in many parts of the world. In Malaysia, the significant progress towards the national elimination programme and effective disease notification on malaria has resulted in zero indigenous human malaria cases since 2018. However, the country still needs to determine the extent of malaria exposure and transmission patterns, particularly in high-risk populations. In this study, a serological method was used to measure transmission levels of

Topics: Antibody Formation; Cross-Sectional Studies; Humans; Malaria; Malaria, Falciparum; Malaria, Vivax; Malaysia; Plasmodium falciparum; Plasmodium vivax; Seroepidemiologic Studies

Reported incidence of the zoonotic malaria Plasmodium knowlesi has markedly increased across Southeast Asia and threatens malaria elimination. Nonzoonotic transmission of P. knowlesi has been experimentally demonstrated, but it remains unknown whether nonzoonotic transmission is contributing to increases in P. knowlesi cases. Here, we adapt model-based inference methods to estimate R

Topics: Humans; Malaria; Malaria, Falciparum; Malaria, Vivax; Malaysia; Plasmodium knowlesi

Increasing reports of resistance to a frontline malaria blood-stage treatment, chloroquine (CQ), raises concerns for the elimination of Plasmodium vivax. The absence of an effective molecular marker of CQ resistance in P. vivax greatly constrains surveillance of this emerging threat. A recent genetic cross between CQ sensitive (CQS) and CQ resistant (CQR) NIH-1993 strains of P. vivax linked a moderate CQR phenotype with two candidate markers in P. vivax CQ resistance transporter gene (

Topics: Alleles; Antimalarials; Chloroquine; Drug Resistance; Humans; Malaria, Vivax; Malaysia; Plasmodium vivax; Protozoan Proteins

Through the regional control programme, Malaysia has been successfully reducing the incidence of Plasmodium falciparum and Plasmodium vivax infections. However, the incidence of zoonotic malaria Plasmodium knowlesi infection is increasing and now has been the major cause of malaria in Malaysia especially Malaysian Borneo. The emergence of knowlesi infection has threatened the malaria elimination programme which the government aims to reduce the overall malaria infections by 2020. Unlike other benign human Plasmodium spp., P. knowlesi can cause fatal infections. The aim of this study was to determine the incidence and distribution of five human malaria parasites including P. knowlesi in Peninsular Malaysia and Malaysian Borneo. A total of 112 blood samples were collected from seven states and district hospitals in Peninsular Malaysia and Malaysian Borneo from year 2015 to 2016. The samples were examined by microscopy and further confirmed by nested PCR assay targeting 18S rRNA gene of Plasmodium spp. Following the nested PCR assays, a total of 54 (48.2%) samples were positive for P. knowlesi infections, 12 (10.7%) cases were positive for P. vivax infections, followed by 7 (6.3%) cases of P. falciparum and 4 (3.5%) cases of P. malariae. There were 3 cases (2.7%) of mixed infections (P. knowlesi/P. vivax). However, no cases were identified as P. ovale. A total of 32 (28.6%) cases were found as negative infections. LoopMediated Isothermal Amplification Assay (LAMP) was performed to confirm inconclusive results produced by microscopy and nested PCR. P. knowlesi showed the highest prevalence in Sarawak (n= 30), Sabah (n=13), Pulau Pinang (n=5) and Pahang (n=6). PCR and LAMP was not able to detect a large number of microscopy positive samples due to DNA degradation during storage and shipping. Among all the states involved in this study, the highest prevalence of P. knowlesi infection was found in Sabah and Sarawak.

Topics: Hospitals; Humans; Incidence; Malaria; Malaria, Falciparum; Malaria, Vivax; Malaysia; Plasmodium knowlesi

Five children in Pos Lenjang, Pahang, Malaysia were PCR-positive for vivax malaria and were admitted to the hospital from 5 to 26 July 2019. One of the patients experienced three episodes of recurrence of vivax malaria. Microsatellite analysis showed that reinfection is unlikely. Drug resistance analysis indicated that Riamet (artemether-lumefantrine) is effective. Cytochrome P450 2D6 (CYP2D6) testing showed that this patient has defective CYP2D6 function. Primaquine failure to clear the Plasmodium vivax hypnozoites may be the cause of recurring infections in this patient. This report highlights the need for the development of liver-stage curative antimalarials that do not require metabolism by the CYP2D6 enzyme.

Topics: Antimalarials; Artemether; Artemether, Lumefantrine Drug Combination; Child; Cytochrome P-450 CYP2D6; Humans; Malaria, Vivax; Malaysia; Plasmodium vivax; Primaquine; Recurrence

Topics: Adolescent; Adult; Asymptomatic Infections; Female; Humans; Malaria; Malaria, Vivax; Malaysia; Male; Middle Aged; Plasmodium; Plasmodium knowlesi; Plasmodium ovale; Plasmodium vivax; Polymerase Chain Reaction; Prevalence; Young Adult

Anaemia is a major consequence of malaria, caused by the removal of both infected and uninfected red blood cells (RBCs) from the circulation. Complement activation and reduced expression of complement regulatory proteins (CRPs) on RBCs are an important pathogenic mechanism in severe malarial anaemia in both Plasmodium falciparum and Plasmodium vivax infection. However, little is known about loss of CRPs on RBCs during mild malarial anaemia and in low-density infection.. The expression of CRP CR1, CD55, CD59, and the phagocytic regulator CD47, on uninfected normocytes and reticulocytes were assessed in individuals from two study populations: (1) P. falciparum and P. vivax-infected patients from a low transmission setting in Sabah, Malaysia; and, (2) malaria-naïve volunteers undergoing P. falciparum induced blood-stage malaria (IBSM). For clinical infections, individuals were categorized into anaemia severity categories based on haemoglobin levels. For IBSM, associations between CRPs and haemoglobin level were investigated.. CRP expression on RBC was lower in Malaysian individuals with P. falciparum and P. vivax mild malarial anaemia compared to healthy controls. CRP expression was also reduced on RBCs from volunteers during IBSM. Reduction occurred on normocytes and reticulocytes. However, there was no significant association between reduced CRPs and haemoglobin during IBSM.. Removal of CRPs occurs on both RBCs and reticulocytes during Plasmodium infection even in mild malarial anaemia and at low levels of parasitaemia.

Topics: Adult; Anemia; Complement System Proteins; Erythrocytes; Female; Humans; Malaria, Falciparum; Malaria, Vivax; Malaysia; Male; Middle Aged; Plasmodium falciparum; Plasmodium vivax; Young Adult

Malaysia has declared its aim to eliminate malaria with a goal of achieving zero local transmission by the year 2020. However, targeting the human reservoir of infection, including those with asymptomatic infection is required to achieve malaria elimination. Diagnosing asymptomatic malaria is not as straightforward due to the obvious lack of clinical manifestations and often subpatent level of parasites. Accurate diagnosis of malaria is important for providing realistic estimates of malaria burden and preventing misinformed interventions. Low levels of parasitaemia acts as silent reservoir of transmission thus remains infectious to susceptible mosquito vectors. Hence, the aim of this study is to investigate the prevalence of asymptomatic submicroscopic malaria (SMM) in the District of Belaga, Sarawak.. In 2013, a total of 1744 dried blood spots (DBS) were obtained from residents of 8 longhouses who appeared healthy. Subsequently, 251 venous blood samples were collected from residents of 2 localities in 2014 based on the highest number of submicroscopic cases from prior findings. Thin and thick blood films were prepared from blood obtained from all participants in this study. Microscopic examination were carried out on all samples and a nested and nested multiplex PCR were performed on samples collected in 2013 and 2014 respectively.. No malaria parasites were detected in all the Giemsa-stained blood films. However, of the 1744 samples, 29 (1.7%) were positive for Plasmodium vivax by PCR. Additionally, of the 251 samples, the most prevalent mono-infection detected by PCR was Plasmodium falciparum 50 (20%), followed by P. vivax 39 (16%), P. knowlesi 9 (4%), and mixed infections 20 (8%).. This research findings conclude evidence of Plasmodium by PCR, among samples previously undetectable by routine blood film microscopic examination, in local ethnic minority who are clinically healthy. SMM in Belaga district is attributed not only to P. vivax, but also to P. falciparum and P. knowlesi. In complementing efforts of programme managers, there is a need to increase surveillance for SMM nationwide to estimate the degree of SMM that warrant measures to block new transmission of malaria.

Topics: Adolescent; Adult; Asymptomatic Infections; Carrier State; Child; Child, Preschool; Coinfection; Disease Reservoirs; Female; Humans; Infant; Infant, Newborn; Malaria; Malaria, Falciparum; Malaria, Vivax; Malaysia; Male; Microscopy; Parasitemia; Plasmodium; Plasmodium falciparum; Plasmodium knowlesi; Plasmodium vivax; Polymerase Chain Reaction; Young Adult

Although

Topics: Adolescent; Adult; Child; Child, Preschool; Diagnostic Tests, Routine; Disease Outbreaks; Female; Humans; Infant; Malaria, Falciparum; Malaria, Vivax; Malaysia; Male; Middle Aged; Phylogeny; Plasmodium falciparum; Plasmodium vivax; Polymerase Chain Reaction; Young Adult

Primaquine is essential for the radical cure of vivax malaria, however its broad application is hindered by the risk of drug-induced haemolysis in individuals with glucose-6-phosphate-dehydrogenase (G6PD) deficiency. Rapid diagnostic tests capable of diagnosing G6PD deficiency are now available, but these are not used widely.. A series of qualitative interviews were conducted with policy makers and healthcare providers in four vivax-endemic countries. Routine G6PD testing is not part of current policy in Bangladesh, Cambodia or China, but it is in Malaysia. The interviews were analysed with regard to respondents perceptions of vivax malaria, -primaquine based treatment for malaria and the complexities of G6PD deficiency.. Three barriers to the roll-out of routine G6PD testing were identified in all sites: (a) a perceived low risk of drug-induced haemolysis; (b) the perception that vivax malaria was benign and accordingly treatment with primaquine was not regarded as a priority; and, (c) the additional costs of introducing routine testing. In Malaysia, respondents considered the current test and treat algorithm suitable and the need for an alternative approach was only considered relevant in highly mobile and hard to reach populations.. Greater efforts are needed to increase awareness of the benefits of the radical cure of Plasmodium vivax and this should be supported by economic analyses exploring the cost effectiveness of routine G6PD testing.

Topics: Administrative Personnel; Bangladesh; Cambodia; China; Diagnostic Tests, Routine; Glucosephosphate Dehydrogenase Deficiency; Health Knowledge, Attitudes, Practice; Health Personnel; Humans; Malaria, Vivax; Malaysia; Primaquine

Plasmodium knowlesi, a simian malaria parasite, has become the main cause of malaria in Sarawak, Malaysian Borneo. Epidemiological data on malaria for Sarawak has been derived solely from hospitalized patients, and more accurate epidemiological data on malaria is necessary. Therefore, a longitudinal study of communities affected by knowlesi malaria was undertaken.. A total of 3002 blood samples on filter paper were collected from 555 inhabitants of 8 longhouses with recently reported knowlesi malaria cases in the Betong Division of Sarawak, Malaysian Borneo. Each longhouse was visited bimonthly for a total of 10 times during a 21-month study period (Jan 2014-Oct 2015). DNA extracted from blood spots were examined by a nested PCR assay for Plasmodium and positive samples were then examined by nested PCR assays for Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae, Plasmodium ovale, Plasmodium knowlesi, Plasmodium cynomolgi and Plasmodium inui. Blood films of samples positive by PCR were also examined by microscopy.. Genus-specific PCR assay detected Plasmodium DNA in 9 out of 3002 samples. Species-specific PCR identified 7 P. knowlesi and one P. vivax. Malaria parasites were observed in 5 thick blood films of the PCR positive samples. No parasites were observed in blood films from one knowlesi-, one vivax- and the genus-positive samples. Only one of 7 P. knowlesi-infected individual was febrile and had sought medical treatment at Betong Hospital the day after sampling. The 6 knowlesi-, one vivax- and one Plasmodium-infected individuals were afebrile and did not seek any medical treatment.. Asymptomatic human P. knowlesi and P. vivax malaria infections, but not P. cynomolgi and P. inui infections, are occurring within communities affected with malaria.

Topics: Adult; Aged; Aged, 80 and over; Asymptomatic Infections; Borneo; Dried Blood Spot Testing; Female; Humans; Longitudinal Studies; Malaria; Malaria, Vivax; Malaysia; Male; Middle Aged; Plasmodium; Plasmodium cynomolgi; Plasmodium knowlesi; Plasmodium vivax; Young Adult

Recurrence rates of Plasmodium vivax infections differ across various geographic regions. Interestingly, South-East Asia and the Asia-Pacific region are documented to exhibit the most frequent recurrence incidences. Identifying patients at a higher risk for recurrences gives valuable information in strengthening the efforts to control P. vivax infections. The aim of the study was to develop a tool to identify P. vivax- infected patients that are at a higher risk of recurrence in Malaysia.. Patient data was obtained retrospectively through the Ministry of Health, Malaysia, from 2011 to 2016. Patients with incomplete data were excluded. A total of 2044 clinical P. vivax malaria cases treated with primaquine were included. Data collected were patient, disease, and treatment characteristics. Two-thirds of the cases (n = 1362) were used to develop a clinical risk score, while the remaining third (n = 682) was used for validation.. Using multivariate analysis, age (p = 0.03), gametocyte sexual count (p = 0.04), indigenous transmission (p = 0.04), type of treatment (p = 0.12), and incomplete primaquine treatment (p = 0.14) were found to be predictors of recurrence after controlling for other confounding factors; these predictors were then used in developing the final model. The beta-coefficient values were used to develop a clinical scoring tool to predict possible recurrence. The total scores ranged between 0 and 8. A higher score indicated a higher risk for recurrence (odds ratio [OR]: 1.971; 95% confidence interval [CI]: 1.562-2.487; p ≤ 0.001). The area under the receiver operating characteristic (ROC) curve of the developed (n = 1362) and validated model (n = 682) was of good accuracy (ROC: 0.728, 95% CI: 0.670-0.785, p value < 0.001, and ROC: 0.766, 95% CI: 0.700-0.833, p-value < 0.001, respectively). In both the developed and validated models, area under the ROC curves showed no significant difference in predicting recurrence based on the constructed scoring mechanism (p = 0.399; Z-value: -0.8441; standard error: 0.045).. The developed model to predict recurrence was found to be of good accuracy and could be a useful tool in targeting patients at a higher risk for recurrence for closer monitoring during follow-up, after treatment with primaquine.

Topics: Adolescent; Adult; Age Factors; Aged; Aged, 80 and over; Antimalarials; Area Under Curve; Child; Child, Preschool; Female; Humans; Infant; Infant, Newborn; Life Cycle Stages; Logistic Models; Malaria, Vivax; Malaysia; Male; Middle Aged; Multivariate Analysis; Odds Ratio; Plasmodium vivax; Primaquine; Recurrence; Retrospective Studies; ROC Curve; Treatment Adherence and Compliance; Young Adult

Malaria cases persist in some remote areas in Sabah and Sarawak despite the ongoing and largely successful malaria control programme conducted by the Vector Borne Disease Control Programme, Ministry Of Health, Malaysia. Point mutations in the genes that encode the two enzymes involved in the folate biosynthesis pathway, dihydrofolate reductase (DHFR) and dihydropteroate synthase (DHPS) enzymes confer resistance to pyrimethamine and sulfadoxine respectively, in both Plasmodium falciparum and P. vivax. The aim of the current study was to determine the mutation on both pvdhfr at codon 13, 33, 57, 58, 61, 117, and 173 and pvdhps genes at codon 383 and 553, which are potentially associated with resistance to pyrimethamine and sulfadoxine in P. vivax samples in Sabah.. Every individual was screened for presence of malaria infection using a commercial rapid dipstick assay, ParaMax-3™ (Zephyr Biomedical, India). Individuals tested positive for P. vivax had blood collected and parasite DNA extracted. The pvdhfr and pvdhps genes were amplified by nested-PCR. Restriction fragment length polymorphism (RFLP) was carried out for detection of specific mutations in pvdhfr at codons 13Leu, 33Leu, 57Ile/Leu, 58Arg, 61Met, 117Asn/Thr, and 173Leu and pvdhps at codons 383Gly and 553Gly. The PCR-RFLP products were analysed using the Agilent 2100 Bioanalyzer (Agilent Technology, AS).. A total of 619 and 2119 individuals from Kalabakan and Kota Marudu, respectively participated in the study. In Kalabakan and Kota Marudu, 9.37 and 2.45 % were tested positive for malaria and the positivity for P. vivax infection was 4.2 and 0.52 %, respectively. No mutation was observed at codon 13, 33 and 173 on pvdhfr and at codon 553 on pvdhps gene on samples from Kalabakan and Kota Marudu. One-hundred per cent mutations on pvdhfr were at 57Leu and 117Thr. Mutation at 58Arg and 61Met was observed to be higher in Kota Marudu 72.73 %. Mutation at 383Gly on pvdhps was highest in Kalabakan with 80.77 %. There are four distinct haplotypes of pvdhfr/pvdhps combination.. The presence of triple and quintuple mutation combination suggest that the P. vivax isolates exhibit a high degree of resistant to sulfadoxine, pyrimethamine and sulfadoxine-pyrimethamine combination therapy.

Topics: Dihydropteroate Synthase; Haplotypes; Humans; Malaria, Vivax; Malaysia; Mutation; Plasmodium vivax; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; Protozoan Proteins; Tetrahydrofolate Dehydrogenase

Plasmodium vivax malaria has a wide geographic distribution and poses challenges to malaria elimination that are likely to be greater than those of P. falciparum. Diagnostic tools for P. vivax infection in non-reference laboratory settings are limited to microscopy and rapid diagnostic tests but these are unreliable at low parasitemia. The development and validation of a high-throughput and sensitive assay for P. vivax is a priority.. A high-throughput LAMP assay targeting a P. vivax mitochondrial gene and deploying colorimetric detection in a 96-well plate format was developed and evaluated in the laboratory. Diagnostic accuracy was compared against microscopy, antigen detection tests and PCR and validated in samples from malaria patients and community controls in a district hospital setting in Sabah, Malaysia.. The high throughput LAMP-P. vivax assay (HtLAMP-Pv) performed with an estimated limit of detection of 1.4 parasites/ μL. Assay primers demonstrated cross-reactivity with P. knowlesi but not with other Plasmodium spp. Field testing of HtLAMP-Pv was conducted using 149 samples from symptomatic malaria patients (64 P. vivax, 17 P. falciparum, 56 P. knowlesi, 7 P. malariae, 1 mixed P. knowlesi/P. vivax, with 4 excluded). When compared against multiplex PCR, HtLAMP-Pv demonstrated a sensitivity for P. vivax of 95% (95% CI 87-99%); 61/64), and specificity of 100% (95% CI 86-100%); 25/25) when P. knowlesi samples were excluded. HtLAMP-Pv testing of 112 samples from asymptomatic community controls, 7 of which had submicroscopic P. vivax infections by PCR, showed a sensitivity of 71% (95% CI 29-96%; 5/7) and specificity of 93% (95% CI87-97%; 98/105).. This novel HtLAMP-P. vivax assay has the potential to be a useful field applicable molecular diagnostic test for P. vivax infection in elimination settings.

Topics: High-Throughput Screening Assays; Humans; Malaria, Vivax; Malaysia; Nucleic Acid Amplification Techniques; Plasmodium; Plasmodium vivax

During 2009 to 2010, a total of 408 blood samples collected from malaria patients in Ranong (149) and Yala (259) Provinces, Thailand were investigated for Plasmodium spp using microscopic examination. There are no statistical differences in the prevalence of P. falciparum and P. vivax in samples collected from Ranong and Yala (46% vs 52%, and 54% vs 45%, respectively). Single nucleotide polymorphism of codon 86 in pfmdr1 (encoding P. falciparum multidrug resistance protein 1) was investigated among 75 samples of P. falciparum and 2 samples of P. knowlesi. A pfmdr1 N86Y mutation was detected in 1 out of 29 samples and 45 out of 46 samples obtained from Ranong and Yala Provinces, respectively. It is interesting that pfmdr1 was detected in two P. knowlesi DNA samples obtained previously from Ranong Province which was 99% homologous to pfmdr1 obtained from falciparum parasites in the same area but the mutation was not observed. The difference in multidrug resistance protein in Plasmodium obtained from those two border areas of Thailand will be of use in monitoring drug resistance in these border regions of the country.

Topics: Codon; DNA, Protozoan; Drug Resistance; Drug Resistance, Multiple; Humans; Malaria; Malaria, Falciparum; Malaria, Vivax; Malaysia; Multidrug Resistance-Associated Proteins; Mutation; Myanmar; Plasmodium falciparum; Plasmodium knowlesi; Plasmodium vivax; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; Polymorphism, Single Nucleotide; Thailand

Plasmodium knowlesi has long been present in Malaysia, and is now an emerging cause of zoonotic human malaria. Cases have been confirmed throughout South-East Asia where the ranges of its natural macaque hosts and Anopheles leucosphyrus group vectors overlap. The majority of cases are from Eastern Malaysia, with increasing total public health notifications despite a concurrent reduction in Plasmodium falciparum and P. vivax malaria. The public health implications are concerning given P. knowlesi has the highest risk of severe and fatal disease of all Plasmodium spp in Malaysia. Current patterns of risk and disease vary based on vector type and competence, with individual exposure risks related to forest and forest-edge activities still poorly defined. Clustering of cases has not yet been systematically evaluated despite reports of peri-domestic transmission and known vector competence for human-to-human transmission.. A population-based case-control study will be conducted over a 2-year period at two adjacent districts in north-west Sabah, Malaysia. Confirmed malaria cases presenting to the district hospital sites meeting relevant inclusion criteria will be requested to enrol. Three community controls matched to the same village as the case will be selected randomly. Study procedures will include blood sampling and administration of household and individual questionnaires to evaluate potential exposure risks associated with acquisition of P. knowlesi malaria. Secondary outcomes will include differences in exposure variables between P. knowlesi and other Plasmodium spp, risk of severe P. knowlesi malaria, and evaluation of P. knowlesi case clustering. Primary analysis will be per protocol, with adjusted ORs for exposure risks between cases and controls calculated using conditional multiple logistic regression models.. This study has been approved by the human research ethics committees of Malaysia, the Menzies School of Health Research, Australia, and the London School of Hygiene and Tropical Medicine, UK.

Topics: Animals; Anopheles; Case-Control Studies; Disease Vectors; Female; Forests; Humans; Macaca; Malaria; Malaria, Falciparum; Malaria, Vivax; Malaysia; Male; Plasmodium knowlesi; Research Design; Residence Characteristics; Risk Factors

Malaria may be a serious complication of blood transfusion due to the asymptomatic persistence of parasites in some donors. This case report highlights the transfusion-transmitted malaria of Plasmodium vivax in a child diagnosed with germ cell tumour. This child had received blood transfusion from three donors and a week later started developing malaria like symptoms. Nested PCR and sequencing confirmed that one of the three donors was infected with P. vivax and this was transmitted to the 12-year-old child. To the best of the authors' knowledge, this is the first reported transfusion-transmitted malaria case in Malaysia.

Topics: Child; DNA, Protozoan; Humans; Malaria, Vivax; Malaysia; Male; Neoplasms, Germ Cell and Embryonal; Plasmodium vivax; Polymerase Chain Reaction; Sequence Analysis, DNA; Transfusion Reaction

Despite significant progress in the control of malaria in Malaysia, the complex transmission dynamics of P. vivax continue to challenge national efforts to achieve elimination. To assess the impact of ongoing interventions on P. vivax transmission dynamics in Sabah, we genotyped 9 short tandem repeat markers in a total of 97 isolates (8 recurrences) from across Sabah, with a focus on two districts, Kota Marudu (KM, n = 24) and Kota Kinabalu (KK, n = 21), over a 2 year period. STRUCTURE analysis on the Sabah-wide dataset demonstrated multiple sub-populations. Significant differentiation (F ST  = 0.243) was observed between KM and KK, located just 130 Km apart. Consistent with low endemic transmission, infection complexity was modest in both KM (mean MOI  = 1.38) and KK (mean MOI  = 1.19). However, population diversity remained moderate (H E  = 0.583 in KM and H E  = 0.667 in KK). Temporal trends revealed clonal expansions reflecting epidemic transmission dynamics. The haplotypes of these isolates declined in frequency over time, but persisted at low frequency throughout the study duration. A diverse array of low frequency isolates were detected in both KM and KK, some likely reflecting remnants of previous expansions. In accordance with clonal expansions, high levels of Linkage Disequilibrium (I A (S) >0.5 [P<0.0001] in KK and KM) declined sharply when identical haplotypes were represented once (I A (S)  = 0.07 [P = 0.0076] in KM, and I A (S) = -0.003 [P = 0.606] in KK). All 8 recurrences, likely to be relapses, were homologous to the prior infection. These recurrences may promote the persistence of parasite lineages, sustaining local diversity. In summary, Sabah's shrinking P. vivax population appears to have rendered this low endemic setting vulnerable to epidemic expansions. Migration may play an important role in the introduction of new parasite strains leading to epidemic expansions, with important implications for malaria elimination.

Topics: DNA, Protozoan; Endemic Diseases; Genetic Variation; Genotype; Humans; Linkage Disequilibrium; Malaria, Vivax; Malaysia; Plasmodium vivax; Prevalence; Recurrence

Plasmodium knowlesi commonly causes severe malaria in Malaysian Borneo, with high case-fatality rates reported. We compared risk, spectrum, and outcome of severe disease from P. knowlesi, Plasmodium falciparum, and Plasmodium vivax and outcomes following introduction of protocols for early referral and intravenous artesunate for all severe malaria.. From September 2010 to October 2011 we prospectively assessed nonpregnant patients aged ≥12 years admitted to Queen Elizabeth Hospital (QEH), Sabah, with polymerase chain reaction-confirmed Plasmodium monoinfection. Standardized referral and prereferral intravenous artesunate were instituted at district hospitals.. Severe malaria occurred in 38 of 130 (29%) patients with P. knowlesi, 13 of 122 (11%) with P. falciparum, and 7 of 43 (16%) with P. vivax. The commonest severity criteria in knowlesi malaria included parasitemia >100 000/µL (n = 18), jaundice (n = 20), respiratory distress (n = 14), hypotension (n = 13), and acute kidney injury (n = 9). On multivariate analysis, P. knowlesi was associated with a 2.96-fold (95% confidence interval, 1.19-7.38-fold) greater risk of severity than P. falciparum (P = .020); only parasitemia and schizontemia >10% independently predicted knowlesi severity. Risk of severe knowlesi malaria increased 11-fold with parasitemia >20 000/µL, and 28-fold with parasitemia >100 000/µL. Nearly all (92%) knowlesi malaria patients received oral artemisinin therapy; 36 of 38 (95%) and 39 of 92 (42%) with severe and nonsevere disease, respectively, also received ≥1 dose of intravenous artesunate. No deaths occurred from any species.. Plasmodium knowlesi is the commonest cause of severe malaria at QEH, with parasitemia the major risk factor for severity. Early referral and treatment with artesunate was highly effective for severe malaria from all species and associated with zero mortality.

Topics: Adult; Aged; Antimalarials; Artemisinins; Artesunate; Female; Humans; Malaria; Malaria, Falciparum; Malaria, Vivax; Malaysia; Male; Middle Aged; Parasitemia; Plasmodium falciparum; Plasmodium knowlesi; Plasmodium vivax; Prospective Studies; Risk Factors; Severity of Illness Index; Time Factors; Treatment Outcome; Young Adult

Malaria is endemic in Malaysia. Leishmaniasis is a protozoan infection rarely reported in Malaysia. Here, a 24-year-old Nepalese man who presented with prolonged fever and hepatosplenomegaly is reported. Blood film examination confirmed a Plasmodium vivax malaria infection. Despite being adequately treated for malaria, his fever persisted. Bone marrow examination showed presence of Leishman-Donovan complex. He was successfully treated with prolonged course of amphotericin B. The case highlights the importance of awareness among the treating physicians of this disease occurring in a foreign national from an endemic region when he presents with fever and hepatosplenomegaly. Coinfection with malaria can occur although it is rare. It can cause significant delay of the diagnosis of leishmaniasis.

Topics: Amphotericin B; Antiprotozoal Agents; Bone Marrow; Coinfection; Emigrants and Immigrants; Humans; Leishmaniasis, Visceral; Malaria, Vivax; Malaysia; Male; Treatment Outcome; Young Adult

Plasmodium knowlesi is increasingly recognized as a cause of human malaria in Southeast Asia but there are no detailed prospective clinical studies of naturally acquired infections.. In a systematic study of the presentation and course of patients with acute P. knowlesi infection, clinical and laboratory data were collected from previously untreated, nonpregnant adults admitted to the hospital with polymerase chain reaction-confirmed acute malaria at Kapit Hospital (Sarawak, Malaysia) from July 2006 through February 2008.. Of 152 patients recruited, 107 (70%) had P. knowlesi infection, 24 (16%) had Plasmodium falciparum infection, and 21 (14%) had Plasmodium vivax. Patients with P. knowlesi infection presented with a nonspecific febrile illness, had a baseline median parasitemia value at hospital admission of 1387 parasites/microL (interquartile range, 6-222,570 parasites/microL), and all were thrombocytopenic at hospital admission or on the following day. Most (93.5%) of the patients with P. knowlesi infection had uncomplicated malaria that responded to chloroquine and primaquine treatment. Based on World Health Organization criteria for falciparum malaria, 7 patients with P. knowlesi infection (6.5%) had severe infections at hospital admission. The most frequent complication was respiratory distress, which was present at hospital admission in 4 patients and developed after admission in an additional 3 patients. P. knowlesi parasitemia at hospital admission was an independent determinant of respiratory distress, as were serum creatinine level, serum bilirubin, and platelet count at admission (p < .002 for each). Two patients with knowlesi malaria died, representing a case fatality rate of 1.8% (95% confidence interval, 0.2%-6.6%).. Knowlesi malaria causes a wide spectrum of disease. Most cases are uncomplicated and respond promptly to treatment, but approximately 1 in 10 patients develop potentially fatal complications.

Topics: Adolescent; Adult; Aged; Animals; Antimalarials; Blood Chemical Analysis; Chloroquine; Female; Hemoglobins; Hospitalization; Humans; Malaria; Malaria, Falciparum; Malaria, Vivax; Malaysia; Male; Middle Aged; Parasitemia; Plasmodium falciparum; Plasmodium knowlesi; Plasmodium vivax; Primaquine; Prospective Studies; Respiratory Tract Diseases; Thrombocytopenia; Young Adult

An epidemiological cross-sectional study was undertaken to determine the endemicity of malaria among the Orang Asli population of Raub, Pahang. Malaria endemicity was measured in terms of the prevalence of parasitaemia and splenomegaly. A total of 520 Orang Asli were examined. The point prevalence of malaria was 24.2% (95% CI 20.7-25.1), with Plasmodium falciparum (67.5%) being the predominant species. Children < 12 years were at least 3.7 times more likely to be parasitaemic compared to those older. The prevalence of malaria among children 2-<10 years was 38.1% (95% CI 31.6-50.0). Spleen rate among children 2-<10 years old was 22.3% (95% CI 17.1-28.3). The average enlarged spleen size was 1.2. These findings classify the study area as being mesoendemic. Malaria control activities among the Orang Asli should focus on protecting vulnerable subgroups like young children. Measuring the level of malaria endemicity at regular intervals is fundamental in evaluating the effectiveness of malaria control programs.

Topics: Adolescent; Adult; Child; Child, Preschool; Endemic Diseases; Female; Humans; Malaria, Falciparum; Malaria, Vivax; Malaysia; Male; Parasitemia; Plasmodium falciparum; Plasmodium vivax; Prevalence; Rural Population; Splenomegaly; Young Adult

Anopheles mosquitos were surveyed using three trapping technics in four longhouse settlements and their respectively farming zone in western Sarawak, Malaysia. The study area was mountainous with tropical rain forest. An. leucosphyrus and An. donaldi were predominant in the farm huts. An. tessellatus and An. subpictus were more abundant in the village settlements. In both ecotypes, human baited traps yielded a significantly greater proportion of Anopheles mosquito than CDC light traps and landing biting catches. Circumsporozoite antigen positively rate, mosquito survival rate and parasite rate showed that malaria transmission is more intense in farm huts than in longhouse settlements. The entomological inoculation rate of An. donaldi and An. leucosphyrus in farm huts was 0.035 and 0.023, respectively. No sporozoite infections were observed in the main settlements.

Topics: Analysis of Variance; Animals; Anopheles; Chi-Square Distribution; Enzyme-Linked Immunosorbent Assay; Humans; Incidence; Insect Vectors; Malaria, Falciparum; Malaria, Vivax; Malaysia; Plasmodium falciparum; Plasmodium vivax; Population Density; Prevalence; Rural Health

A study on the distribution of malaria in Hulu Perak district, Peninsular Malaysia was carried out between January and December 1993. The study encompassed the distribution of malaria cases according to sex, age and profession. A total of 332 cases were recorded, with 182 cases occurring in males. The highest infection was observed in the above 15 years old age group. Forest workers (loggers, rattan collectors and forest product gatherers) were the group most exposed to the disease (32.8%), followed by both plantantion workers (32.2%) and aboriginal communities (32.2%). Army and police personnels (2.1%) were also infected. Plasmodium falciparum was the most common species of malaria in the area.

Topics: Adolescent; Adult; Child; Child, Preschool; Endemic Diseases; Female; Humans; Infant; Infant, Newborn; Malaria, Falciparum; Malaria, Vivax; Malaysia; Male; Occupational Exposure; Seasons; Thailand

Blood from most of the residents of a remote village in northern peninsular Malaysia, bordering Thailand, was examined for malaria parasites monthly for 1 year. Plasmodium vivax was the commonest infection, but P. falciparum and mixed infections also occurred. Monthly collections of the malaria vector, Anopheles maculatus showed a positive correlation between mosquito densities and malaria positivity in the human population and a negative correlation with rainfall.

Topics: Animals; Anopheles; Humans; Insect Vectors; Malaria, Falciparum; Malaria, Vivax; Malaysia; Population Density; Prevalence; Rain

In spite of more than 30 years of control activities, malaria continues to be the most important parasitic infection in Malaysia, accounting for 39,189 confirmed cases in 1991, giving an annual parasite incidence rate of 2.2 per 1,000 population. Some factors contributing to the continued transmission of malaria are the development of drug resistant Plasmodium falciparum, changes in vector behavior, and ecological changes due to socio-economic reasons. Malaria parasite rates are higher among the Aborigines, land scheme settlers and those in intimate contact with the jungle, like loggers. There has been no substantial change in the proportion of the three common malaria species responsible for infections, P. falciparum, P. vivax, P. malariae and mixed infections accounting for about 70%, 28%, 1% and 1%, respectively of all infections. Drug resistant P. falciparum is unevenly distributed in Malaysia, but based on clinical experience and in vitro drug sensitivity studies, chloroquine resistance is frequently encountered. There has been clinical and laboratory evidence of resistance to sulfadoxine/pyrimethamine combination as well as quinine, but all these have so far been successfully treated with a combination of quinine and tetracycline. The eradication of the disease is impossible in the near future but there is confidence that with better surveillance techniques and the use of alternative control measures like permethrin impregnated bed-nets to complement existing ones, the target of bringing down the annual parasite incidence to 2 per 1,000 population during the Sixth Malaysian Plan period (1991-1995) can be achieved.

Topics: Animals; Drug Resistance; Humans; Malaria; Malaria, Falciparum; Malaria, Vivax; Malaysia; Mosquito Control; Plasmodium falciparum; Plasmodium malariae; Primary Prevention; Seroepidemiologic Studies

The quantitative buffy coat (QBC) technique was compared with the conventional thick blood film technique in a malaria survey carried out in a mesoendemic area of malaria in Betau, Pahang, Malaysia. The QBC technique was found to be a rapid technique but had a sensitivity of about 56% and a specificity of 95%, using the thick blood film method as the "gold standard". Malaria species identification was unsatisfactory with the QBC technique as it could identify parasites correctly in only about 60% of specimens. It was unable to detect as positive about 58% of specimens which had parasite counts < or = 500 per ul but could detect about 94% of those with counts > 500 per ul. This difference in positive detection rate was significantly different (p < 0.05). It cannot quantify parasitemia easily and the specimens cannot be stored for future reference and for quality control purposes. It is therefore concluded that the QBC technique cannot replace the classical thick blood film technique for use in malaria control programmes. Its use may be appropriate in situations like busy blood banks and outpatient clinics where rapid screening of malaria infection is needed but where experienced malaria microscopists may not be available.

Topics: Acridine Orange; Adolescent; Adult; Aged; Animals; Azure Stains; Child; Child, Preschool; Erythrocytes; Humans; Infant; Malaria; Malaria, Falciparum; Malaria, Vivax; Malaysia; Middle Aged; Plasmodium malariae; Sensitivity and Specificity

The malaria parasite rates and densities were compared in 79 ovalocytic-normocytic pairs of Malayan Aborigines matched for age, sex, proximity of residence to each other, and use of bed nets when sleeping in their jungle settlement in central Peninsular Malaysia. Malaria infection was determined from thick and thin Giemsa-stained blood films collected monthly for a period of six months. Blood films from ovalocytic individuals were found to be positive for malaria less often than in persons with normal red blood cells (P less than 0.05). Malaria infections per 100 person-months at risk were 9.7 in the ovalocytic group compared with 15.19 in the normocytic group. Among individuals parasitemic at any time, heavy infections (greater than or equal to 10,000 parasites/mm3 of blood) with Plasmodium falciparum, P. vivax, and P. malariae were encountered only in normocytic subjects, which comprised approximately 12.5% of the malaria-positive individuals in this group. In an earlier survey of 629 settlers that identified subjects for the above study, the prevalence of ovalocytosis was found to increase significantly with age. The above field observations support the view that ovalocytic individuals might have a survival advantage in the face of malaria. Consideration of the ovalocytic factor is indicated in future evaluations of malaria control measures in areas where ovalocytosis is prevalent.. The malaria parasite rates and densities were compared in 79 ovalocytic-normocytic pairs of Malayan Aborigines matched for age, sex, proximity of residence to each other, and use of bednets when sleeping in their jungle settlement in central Peninsular Malaysia. Malaria infection was detected from thick and thin Giemsa-stained blood films collected monthly for a 6-month period. Blood films from ovalocytic individuals were found to be positive for malaria less often than in those individuals with normal red blood cells (p0.05). Malaria infections/100 person-months at risk were 9.7 in the ovalocytic group as compared with 15.19 in the other group. Among those parasitemic at any time, heavy infections (or= 10,000 parasites/cu.mm of blood) with Plasmodium falciparum, P. vivax, and P. malariae were seen only in normocytic subjects, approximately 12.5% of the malaria-positive persons in this group. In an earlier survey of 629 settlers who identified subjects for the above study, the prevalence of ovalocytosis was found to increase significantly with age. The above field observations support the view that ovalocytic individuals might have a survival advantage in the face of malaria. Consideration of the ovalocytic factor is indicated in future evaluations of malaria control measures in those areas where ovalocytosis is prevalent.

Topics: Adolescent; Adult; Age Factors; Child; Child, Preschool; Elliptocytosis, Hereditary; Female; Hemoglobins; Humans; Incidence; Infant; Malaria; Malaria, Falciparum; Malaria, Vivax; Malaysia; Male; Middle Aged; Native Hawaiian or Other Pacific Islander; Prevalence; Racial Groups; Regression Analysis