clove and Malaria--Falciparum

The purpose of this review was to provide up-to-date information on the resistance of Plasmodium falciparum to the main antimalarials used in Madagascar and to assist implementation of the malaria control and elimination program. In 2006, the failure rate for chloroquine treatment was 44% (n = 300) and was comparable to the rate observed in continental Africa. Most treatment failures occurred after the first week of follow-up. P. falciparum resistance to chloroquine appeared to be special in Madagascar with only 3.2% of isolates showing in vitro resistance (n = 372, 7 sentinel sites) and less than 1% harbouring mutant parasites within the Pfcrt gene. Conversely, the Pfmdr1 N86Y point mutation was found in 64.3% (n = 174) of isolates in 2006 and in 51.7% (n = 343) in 2007. Failure of combined sulfadoxine-pyrimethamine therapy, i.e., the recommended intermittent preventive treatment for malaria during pregnancy, and in vitro resistance to pyrimethamine were rare. However, the Pfdhfr 51I/59R/108N allele showed consistently high prevalence levels reaching 33.3% in 2008. Moreover, the single Pfdhfr 164L mutant allele, a haplotype unique to Madagascar, was discovered in 2006 and showed prevalence rates up to 30% in some locations (southeast) in 2008. Up to now, the quadruple mutant allele Pfdhfr 51I/59R/108N/164L has not been observed. Susceptibility to the other antimalarials tested appeared excellent but the number of isolates showing in vitro susceptibility to artemisinin derivatives has been fallen in recent years and this decline may herald a decrease in the efficacy of these drugs.

Topics: Antimalarials; Drug Resistance; Haplotypes; Humans; Madagascar; Malaria, Falciparum; Mutation; Plasmodium falciparum; Tetrahydrofolate Dehydrogenase

Malaria remains a major health problem in Madagascar. Over past decades, the burden of malarial disease has fluctuated over time, partly in line with the successes and failures of antimalarial policy. In the 1950s and 1960s, a sharp decline in malaria transmission was observed in the central highlands due to indoor spraying with DDT and to the massive use of chloroquine by the population. Following this, the discontinuation of the 'nivaquinization' policy was followed by devastating outbreaks in the central highlands in the 1980s. Currently, the rate of in vitro chloroquine-resistant Plasmodium falciparum isolates does not exceed 5%. This figure appears disconnected from the high level of clinical treatment failure (near 40%). pfcrt mutant isolates are found in less than 1% of isolates on the Island. Conversely, pfmdr1 mutant isolates are found in more than 60% of isolates and may be responsible for the bulk of resistance to chloroquine in Madagascar. Other antimalarials remain generally effective in Madagascar. Recent clinical and in vitro data support the complete efficacy of the combination artesunate-amodiaquine in Madagascar. As such, this artemisinin combination therapy should play a central role in the control and possible elimination of P. falciparum malaria in Madagascar

Topics: Animals; Antimalarials; Drug Resistance; Humans; Madagascar; Malaria, Falciparum; Plasmodium falciparum

On the island of Madagascar, malaria was nearly eradicated in the highland areas and malaria transmission was significantly decreased in the coastal areas between the 1940s and 1960s. The success of the control programme was primarily achieved by chloroquine (CQ) use at the community level. CQ was administered to children weekly on a routine basis for malaria prevention in the period 1949-1971. Then, the Malagasy Government was unable to financially support the malaria control programme. The malarial situation worsened in the 1980s, partly due to the shortage of CQ. A malaria epidemic occurred. To deal with this epidemic, massive CQ use was urgently adopted. CQ has remained the first-line drug since 1945, but the prevalence of Plasmodium falciparum carrying the pfcrt mutation associated with CQ resistance remains low (<3%). However, late CQ treatment failure has been reported and the prevalence may be as high as 35% during 14-day follow-up since 1982. In an effort to eliminate malaria as a public health problem, a shift from CQ to artemisinin-based combination therapy has been advocated by a new policy since December 2005. A change of this kind is complex and the lessons learnt from the six decades of CQ use are of the utmost importance to achieve malaria control.

Topics: Adolescent; Animals; Antimalarials; Artemisinins; Child; Chloroquine; Disease Outbreaks; Drug Resistance; Drug Therapy, Combination; Evidence-Based Practice; Health Policy; Humans; Madagascar; Malaria, Falciparum; Membrane Transport Proteins; Plasmodium falciparum; Prevalence; Protozoan Proteins

Madagascar is considered as a sub-region of the Afrotropical geographical Region in spite of the high endemicity of 95% of the invertebrates. Nevertheless the three malaria vectors An. gambiae s.s., An. arabiensis and An. funestus are quite similar to those of the continental Africa. This support the hypothesis of their recent introduction. Plasmodium falciparum is the dominant parasite but the prevalence of P. vivax is not negligible. It is linked to the Asian component of the human population. P. malariae and P. ovale are of minor importance. The main epidemiological "facies" of Africa are found in Madagascar. The equatorial facies on the East Coast is characterized by a high transmission all year long. In the tropical facies on the West Coast transmission is seasonal (7 months at least). In both areas, malaria is stable and the inhabitants acquire a high immunity before the age of ten; most of the severe cases touch children below 10. The three vectors can be found but An. gambiae s.s. is dominant. In the exophilic southern facies the transmission is seasonal (two to four months). The only vector is An. arabiensis. Malaria is unstable and severe epidemics occur during the years of high rainfall. All age groups are vulnerable because the population is not immune in the Plateaux facies above 1,000 m., malaria is unstable. Severe epidemics occurred in 1987-1988. The vectors are An. Arabiensis and An. funestus. The occurrence of P. falciparum on the Plateaux seems linked to the development of irrigation of rice farming in the XIXth century. Most of the anopheles breeding places on the Plateaux are dependent on rice cultivation. Urban development has brought the inhabitants of the suburbs in close contact with rice fields. Despite the high number of anopheline bites the number of malaria cases remains by far lower than in the neighbouring rural areas. Regional migrations inside the island bring non-immune populations, from the south and the plateaux, in highly malarious areas of the coast, where the migrants are exposed to high risk. In spite of 40 years of uncontrolled use, chloroquine can still cure most, if not all, of malaria cases. Control measures appropriated to the different areas of Madagascar are discussed.

Topics: Agriculture; Animals; Anopheles; Chloroquine; Emigration and Immigration; Humans; Insect Vectors; Madagascar; Malaria; Malaria, Falciparum; Malaria, Vivax; Oryza; Plasmodium malariae; Population Surveillance; Prevalence; Risk Factors; Seasons; Severity of Illness Index; Urbanization; Water

Malaria is a major public health problem in Madagascar, particularly in coastal areas. We conducted a randomized, controlled, parallel-group study of artemisinin-based combination therapy (ACT) in Mananjary and Farafangana, two localities on the rainy south-east coast of Madagascar, from March to September 2018. The efficacy and safety of artesunate + amodiaquine (ASAQ) and artemether + lumefantrine (AL) were assessed according to the WHO protocol with a 28-day follow-up. Children aged 6 months to 14 years with uncomplicated Plasmodium falciparum malaria were randomized to receive ASAQ or AL for three days (1:1). 347/352 (98.5%) randomized patients reached the study endpoint on day 28. Crude adequate clinical and parasitological response (ACPR) rates were 100% (95% CI: 98.8-100%) in the ASAQ group and 96% (95% CI: 93.1-98.9%) in the AL group (per protocol population). However, the PCR-corrected ACPR rate was 97.7% (95% CI: 95.4-100%) in the AL group. Two cases of recrudescence and three of re-infection were observed. Mild and moderate adverse events, including gastrointestinal and/or nervous disorders, were reported in 11.9% (42/352) of patients. We found that ASAQ and AL were safe and efficacious for treating uncomplicated P. falciparum malaria. They may be used for treatment at health facilities and at the community level, and for mass drug administration campaigns.. Efficacité thérapeutique et sécurité de l’artésunate + amodiaquine et de l’artéméther + luméfantrine pour le traitement du paludisme simple à Plasmodium falciparum chez les enfants sur la côte sud-est pluvieuse de Madagascar.. Le paludisme demeure un problème majeur de santé publique à Madagascar notamment dans les régions côtières. Nous avons réalisé une étude multisite, randomisée, contrôlée, en groupes parallèles sur la combinaison thérapeutique à base des dérivés d’artémisinine (CTA) à Mananjary et Farafangana, deux localités sur la côte sud-est pluvieuse de Madagascar, de mars au septembre 2018. L’efficacité et la sécurité de l’artésunate + amodiaquine (ASAQ) et de l’artéméther + luméfantrine (AL) ont été évaluées selon le protocole de l’OMS avec un suivi de 28 jours. Des enfants âgés de 6 mois à 14 ans souffrant de paludisme non compliqué à Plasmodium falciparum ont été randomisés (1:1) pour recevoir ASAQ ou AL pendant trois jours. 347/352 (98,5 %) des patients randomisés ont pu être suivis jusqu’au jour 28. Le taux de réponse clinique et parasitologique adéquate (RCPA) était de 100 % (95 % CI : 98,8 – 100 %) dans le bras thérapeutique ASAQ et de 96 % (95 % CI : 93,1 – 98,9 %) dans le bras thérapeutique AL (population per protocole). Cependant, après correction par PCR, le taux de RCPA était de 97,7 % (95 % CI : 95,4 – 100 %) dans le bras thérapeutique AL. Deux cas de recrudescence et trois cas de réinfections ont été observées. Des effets indésirables légers et modérés, notamment des troubles gastro-intestinaux et/ou nerveux, ont été rapportés chez 11,9 % (42/352) des patients. Nos résultats démontrent que l’ASAQ et l’AL sont sûrs et efficaces pour le traitement du paludisme non compliqué à P. falciparum. Ces deux CTA peuvent par conséquent être utilisés pour traiter le paludisme dans les centres de santé et au niveau communautaire, et aussi pendant les campagnes de traitement de masse.

Topics: Amodiaquine; Artemether, Lumefantrine Drug Combination; Artesunate; Child; Humans; Madagascar; Malaria, Falciparum

Gametocytes are the sexual stages ensuring continuity of the development cycle of the parasite, as well as its transmission to humans. The efficacy of artemisinin-based anti-malarials against asexual stages of Plasmodium has been reported in Madagascar, but their effects on gametocytes are not well documented. The present study aims to determine the emergence of gametocyte and gametocyte clearance after artesunate-amodiaquine (ASAQ) or artemether-lumefantrine (AL) treatment in children with uncomplicated Plasmodium falciparum malaria in 5 regions of Madagascar.. 558 children with uncomplicated P. falciparum malaria, aged between 1 and 15 years, were assigned randomly to AL or ASAQ treatment. They come from 5 regions of Madagascar with different epidemiological facies related to malaria: Ankilivalo, Benenitra, Ampanihy, Ankazomborona and Matanga. Gametocytes were identified by microscopy, from t blood smears at day 1, day 2, day 3, day 7, day 14, day 21 and day 28 after treatment.. At baseline, 9.7% (54/558) children [95% CI: 7.4-12.5%] had detectable gametocyte by microscopy. Among the 54 enrolled children, gametocytes emergence rate was high during the first days of treatment in both treatment arms (AL and ASAQ), especially on day 1. Gametocytes were undetectable from day 14 for AL arm while for ASAQ arm, gametocyte carriage was gradually decreased but persisted until day 21.. This study demonstrates that AL has a more rapid effect on gametocyte clearance compared to ASAQ in children with uncomplicated Plasmodium falciparum malaria.

Topics: Adolescent; Amodiaquine; Antimalarials; Artemether; Artemether, Lumefantrine Drug Combination; Artesunate; Child; Child, Preschool; Drug Combinations; Ethanolamines; Humans; Infant; Madagascar; Malaria, Falciparum; Plasmodium falciparum

Since 2005, artemisinin-based combination therapy (ACT) has been recommended to treat uncomplicated falciparum malaria in Madagascar. Artesunate-amodiaquine (ASAQ) and artemether-lumefantrine (AL) are the first- and second-line treatments, respectively. A therapeutic efficacy study was conducted to assess ACT efficacy and molecular markers of anti-malarial resistance.. Children aged six months to 14 years with uncomplicated falciparum malaria and a parasitaemia of 1000-100,000 parasites/µl determined by microscopy were enrolled from May-September 2018 in a 28-day in vivo trial using the 2009 World Health Organization protocol for monitoring anti-malarial efficacy. Participants from two communes, Ankazomborona (tropical, northwest) and Matanga (equatorial, southeast), were randomly assigned to ASAQ or AL arms at their respective sites. PCR correction was achieved by genotyping seven neutral microsatellites in paired pre- and post-treatment samples. Genotyping assays for molecular markers of resistance in the pfk13, pfcrt and pfmdr1 genes were conducted.. Of 344 patients enrolled, 167/172 (97%) receiving ASAQ and 168/172 (98%) receiving AL completed the study. For ASAQ, the day-28 cumulative PCR-uncorrected efficacy was 100% (95% CI 100-100) and 95% (95% CI 91-100) for Ankazomborona and Matanga, respectively; for AL, it was 99% (95% CI 97-100) in Ankazomborona and 83% (95% CI 76-92) in Matanga. The day-28 cumulative PCR-corrected efficacy for ASAQ was 100% (95% CI 100-100) and 98% (95% CI 95-100) for Ankazomborona and Matanga, respectively; for AL, it was 100% (95% CI 99-100) in Ankazomborona and 95% (95% CI 91-100) in Matanga. Of 83 successfully sequenced samples for pfk13, no mutation associated with artemisinin resistance was observed. A majority of successfully sequenced samples for pfmdr1 carried either the NFD or NYD haplotypes corresponding to codons 86, 184 and 1246. Of 82 successfully sequenced samples for pfcrt, all were wild type at codons 72-76.. PCR-corrected analysis indicated that ASAQ and AL have therapeutic efficacies above the 90% WHO acceptable cut-off. No genetic evidence of resistance to artemisinin was observed, which is consistent with the clinical outcome data. However, the most common pfmdr1 haplotypes were NYD and NFD, previously associated with tolerance to lumefantrine.

Topics: Adolescent; Amodiaquine; Antimalarials; Artemether, Lumefantrine Drug Combination; Artemisinins; Child; Child, Preschool; DNA, Protozoan; Drug Combinations; Female; Humans; Infant; Madagascar; Malaria, Falciparum; Male; Multidrug Resistance-Associated Proteins; Plasmodium falciparum; Polymerase Chain Reaction; Polymorphism, Genetic; Pregnancy; Prevalence; Recurrence; Reinfection

Since 2006, the artemisinin-based combination therapy (ACT) are recommended to treat uncomplicated malaria including non Plasmodium falciparum malaria in Madagascar. Artesunate-amodiaquine (ASAQ) and artemether-lumefantrine are the first- and second-line treatment in uncomplicated falciparum malaria, respectively. No clinical drug efficacy study has been published since 2009 to assess the efficacy of these two artemisinin-based combinations in Madagascar, although the incidence of malaria cases has increased from 2010 to 2016. In this context, new data about the efficacy of the drug combinations currently used to treat malaria are needed.. Therapeutic efficacy studies evaluating the efficacy of ASAQ were conducted in 2012, 2013 and 2016 among falciparum malaria-infected patients aged between 6 months and 56 years, in health centres in 6 sites representing different epidemiological patterns. The 2009 World Health Organization protocol for monitoring anti-malarial drug efficacy was followed.. A total of 348 enrolled patients met the inclusion criteria including 108 patients in 2012 (n = 64 for Matanga, n = 44 for Ampasipotsy), 123 patients in 2013 (n = 63 for Ankazomborona, n = 60 for Anjoma Ramartina) and 117 patients in 2016 (n = 67 for Tsaratanana, n = 50 for Antanimbary). The overall cumulative PCR-corrected day 28 cure rate was 99.70% (95% IC 98.30-99.95). No significant difference in cure rates was observed overtime: 99.02% (95% IC 94.65-99.83) in 2012; 100% (95% IC 96.8-100) in 2013 and 100% (95% IC 96.65-100) in 2016.. The ASAQ combination remains highly effective for the treatment of uncomplicated falciparum malaria in Madagascar.

Topics: Adolescent; Adult; Amodiaquine; Antimalarials; Artemisinins; Child; Child, Preschool; Drug Combinations; Female; Humans; Infant; Madagascar; Malaria, Falciparum; Male; Young Adult

There is an on-going debate about whether health products, such as insecticide-treated bednets (ITNs) for protection against malaria, should be distributed for free or at a positive price to maximize ownership and use. One argument in favour of free distribution is related to positive externalities. Like vaccines, individual use of ITNs provides a community-wide protective effect against malaria even for non-users. In addition, price may act as a barrier to ownership particularly among those most at-risk who are frequently poor. Alternatively, charging a positive price may reduce donor dependence, more efficiently allocate nets to those most at risk of malaria, and encourage use through a hypothesized sunk cost effect, where individuals are more likely to use goods they pay for. Using a randomized experiment in Madagascar, we evaluate the impact of price on demand for and use of ITNs. We find that price negatively affects both demand and use of ITNs. When price increases by $0.55, demand falls by 23.1% points (CI 19.6–26.6; P < 0.01) and effective coverage falls by 23.1% points (CI 19.6–26.6; P < 0.01). We fail to find evidence of a screening effect for prices greater than zero, but households eligible for free ITNs are more likely to use them if they have more self-reported fevers in the household at baseline. We also fail to find evidence of a sunk cost effect, meaning that households are not more likely to use nets that they pay for. Our results suggest that: (1) only partially subsidizing ITNs significantly limits ownership and (2) distributing ITNs for free or at a small nominal price will maximize demand and effective coverage. Alternative sources of financing should be identified to completely (or almost completely) subsidize the cost of ITNs in order to maximize coverage of ITNs among poor populations at risk of malaria.

Topics: Adult; Female; Fever; Health Services Needs and Demand; Humans; Insecticide-Treated Bednets; Madagascar; Malaria, Falciparum; Male; Middle Aged; Ownership; Poverty; Rural Population

Early diagnosis, as well as prompt and effective treatment of uncomplicated malaria, are essential components of the anti-malaria strategy in Madagascar to prevent severe malaria, reduce mortality and limit malaria transmission. The purpose of this study was to assess the performance of the malaria rapid diagnostic tests (RDTs) used by community health workers (CHWs) by comparing RDT results with two reference methods (microscopy and Polymerase Chain Reaction, PCR).. Eight CHWs in two districts, each with a different level of endemic malaria transmission, were trained to use RDTs in the management of febrile children under five years of age. RDTs were performed by CHWs in all febrile children who consulted for fever. In parallel, retrospective parasitological diagnoses were made by microscopy and PCR. The results of these different diagnostic methods were analysed to evaluate the diagnostic performance of the RDTs administered by the CHWs. The stability of the RDTs stored by CHWs was also evaluated.. Among 190 febrile children with suspected malaria who visited CHWs between February 2009 and February 2010, 89.5% were found to be positive for malaria parasites by PCR, 51.6% were positive by microscopy and 55.8% were positive by RDT. The performance accuracy of the RDTs used by CHWs in terms of sensitivity, specificity, positive and negative predictive values was greater than 85%. Concordance between microscopy and RDT, estimated by the Kappa value was 0.83 (95% CI: 0.75-0.91). RDTs stored by CHWs for 24 months were capable of detecting Plasmodium falciparum in blood at a level of 200 parasites/μl.. Introduction of easy-to-use diagnostic tools, such as RDTs, at the community level appears to be an effective strategy for improving febrile patient management and for reducing excessive use of anti-malarial drugs.

Topics: Child, Preschool; Community Health Workers; Diagnosis, Differential; Diagnostic Tests, Routine; Female; Fever; Humans; Infant; Madagascar; Malaria, Falciparum; Male; Microscopy; Plasmodium falciparum; Polymerase Chain Reaction; Reproducibility of Results; Retrospective Studies; Sensitivity and Specificity

Topics: Adolescent; Adult; Animals; Antimalarials; Child; Chloroquine; Double-Blind Method; Drug Resistance; Humans; Indole Alkaloids; Madagascar; Malaria, Falciparum; Middle Aged; Phytotherapy; Plasmodium falciparum; Strychnos; Young Adult

In order to improve the monitoring of the antimalarial drug resistance in Madagascar, a new national network based on eight sentinel sites was set up. In 2006/2007, a multi-site randomized clinical trial was designed to assess the therapeutic efficacy of chloroquine (CQ), sulphadoxine-pyrimethamine (SP), amodiaquine (AQ) and artesunate plus amodiaquine combination (ASAQ), the antimalarial therapies recommended by the National Malaria Control Programme (NMCP).. Children between six months and 15 years of age, with uncomplicated falciparum malaria, were enrolled. Primary endpoints were the day-14 and day-28 risks of parasitological failure, either unadjusted or adjusted by genotyping. Risks of clinical and parasitological treatment failure after adjustment by genotyping were estimated using Kaplan-Meier survival analysis. Secondary outcomes included fever clearance, parasite clearance, change in haemoglobin levels between Day 0 and the last day of follow-up, and the incidence of adverse events.. A total of 1,347 of 1,434 patients (93.9%) completed treatment and follow-up to day 28. All treatment regimens, except for the chloroquine (CQ) treatment group, resulted in clinical cure rates above 97.6% by day-14 and 96.7% by day-28 (adjusted by genotyping). Parasite and fever clearance was more rapid with artesunate plus amodiaquine, but the extent of haematological recovery on day-28 did not differ significantly between the four groups. No severe side-effects were observed during the follow-up period.. These findings (i) constitute an up-dated baseline data on the efficacy of antimalarial drugs recommended by the NMCP, (ii) show that antimalarial drug resistance remains low in Madagascar, except for CQ, compared to the bordering countries in the Indian Ocean region such as the Comoros Archipelago and (iii) support the current policy of ASAQ as the first-line treatment in uncomplicated falciparum malaria.

Topics: Adolescent; Antimalarials; Child; Child, Preschool; Drug Resistance; Female; Humans; Infant; Madagascar; Malaria, Falciparum; Male; National Health Programs; Treatment Outcome

Data concerning antimalarial combination treatment for uncomplicated malaria in Madagascar are largely lacking. Randomized clinical trial was designed to assess therapeutic efficacies of chloroquine (CQ), amodiaquine (AQ), sulphadoxine-pyrimethamine (SP), amodiaquine plus sulphadoxine-pyrimethamine combination (AQ+SP) and artesunate plus amodiaquine combination (AQ+AS).. 287 children between 6 months and 15 years of age, with uncomplicated falciparum malaria, were enrolled in the study. Primary endpoints were the day-14 and day-28 risks of parasitological failure, either unadjusted or adjusted by genotyping.. All treatment regimens, except for CQ treatment, gave clinical cure rates above 97% by day-14 and 92% by day-28 (PCR-corrected). AQ+SP was as effective as AQ+AS. The risk of new infection within the month after therapy was generally higher for AQ+AS than AQ+SP.. These findings show that the inexpensive and widely available combination AQ+SP may be valuable in for the treatment of uncomplicated malaria in Madagascar and could have an important role in this country, where much of the drugs administered go to patients who do not have malaria.

Topics: Adolescent; Amodiaquine; Antimalarials; Artemisinins; Artesunate; Child; Child, Preschool; Chloroquine; Drug Combinations; Drug Therapy, Combination; Humans; Infant; Madagascar; Malaria, Falciparum; Pyrimethamine; Sesquiterpenes; Sulfadoxine; Treatment Outcome

A controlled randomized trial of anti-helminthic treatment was undertaken in 1996-1997 in a rural area of Madagascar where populations were simultaneously infected with Ascaris lumbricoides, Plasmodium falciparum, and Schistosoma mansoni. Levamisole was administered bimonthly to 107 subjects, whereas 105 were controls. Levamisole was highly effective in reducing Ascaris egg loads in the treated group (P < 10(-3) at all visits), whereas it had no effect on schistosomiasis. Subjects 5-14 years of age, treated with levamisole, had a significant increase of their P. falciparum densities compared with controls (P = 0.003). There was no effect of the treatment on children 6 months to 4 years of age, nor on adults > 15 years of age. This study confirms the results of a randomized trial, which showed a negative interaction in those > 5 years of age between Ascaris and malaria parasite density in another Malagasy population, submitted to a higher malaria transmission.

Topics: Adolescent; Age Factors; Animals; Anthelmintics; Ascariasis; Ascaris lumbricoides; Child; Child, Preschool; Female; Humans; Infant; Levamisole; Madagascar; Malaria, Falciparum; Male; Parasite Egg Count; Plasmodium falciparum; Schistosoma mansoni; Schistosomiasis; Seasons; Time Factors

In order to document the evolution of the chemoresistance of Plasmodium falciparum to chloroquine in Madagascar, a study was carried out in Sainte-Marie island located at 6 km on the eastern border of the country. Symptomatic malaria patients who satisfied criteria for resistance testing, were recruited by a process of passive case detection at two clinics. These patients were enrolled in a sensitivity 14-day in vivo test for uncomplicated P. falciparum malaria attacks. All subjects received a supervised therapeutic regimen of chloroquine (25 mg base/kg over 3 days). Parasitemia and symptoms were monitored for 14 days. 62 (93.9%) out of the 66 enrolled patients completed the 14-day follow-up. A total of 50 of 62 patients (80.6%) presented an adequate clinical response. Early and late treatment failures were observed in 3 (4.8%) and 9 (14.5%) patients respectively. Failure therapeutic treatments treated with sulfadoxine-pyrimethamine were successful. Chloroquine remains effective in the treatment of malaria due to P. falciparum and therefore its choice as a first line drug remains justified. Likewise, guidelines for the use of sulfadoxine-pyrimethamine as second line drug are adequate. In vitro, 4 resistances out of 27 successful tests to chloroquine (14.8%) and 1 resistance out of 25 successful tests to mefloquine (4%) were recorded. No resistance to quinine nor to amodiaquine were noticed. Alternative antimalarial drugs such as quinine, amodiaquine or mefloquine can be used in patients for whom the treatment with chloroquine is not possible. Nevertheless, the level of therapeutic failures to chloroquine detected in this study highlights the need and importance of drug sensitivity test for the development of a rational national antimalarial drug policy.

Topics: Adolescent; Adult; Animals; Antimalarials; Child; Child, Preschool; Chloroquine; Drug Combinations; Drug Evaluation, Preclinical; Drug Monitoring; Drug Resistance; Female; Geography; Humans; Infant; Madagascar; Malaria, Falciparum; Male; Middle Aged; Parasitic Sensitivity Tests; Patient Selection; Plasmodium falciparum; Pyrimethamine; Sulfadoxine; Treatment Outcome

Histidine-rich protein 2 (HRP2)-based rapid diagnostic tests detect Plasmodium falciparum malaria and are used throughout sub-Saharan Africa. However, deletions in the pfhrp2 and related pfhrp3 (pfhrp2/3) genes threaten use of these tests. Therapeutic efficacy studies (TESs) enroll persons with symptomatic P. falciparum infection. We screened TES samples collected during 2016-2018 in Ethiopia, Kenya, Rwanda, and Madagascar for HRP2/3, pan-Plasmodium lactate dehydrogenase, and pan-Plasmodium aldolase antigen levels and selected samples with low levels of HRP2/3 for pfhrp2/3 genotyping. We observed deletion of pfhrp3 in samples from all countries except Kenya. Single-gene deletions in pfhrp2 were observed in 1.4% (95% CI 0.2%-4.8%) of Ethiopia samples and in 0.6% (95% CI 0.2%-1.6%) of Madagascar samples, and dual pfhrp2/3 deletions were noted in 2.0% (95% CI 0.4%-5.9%) of Ethiopia samples. Although this study was not powered for precise prevalence estimates, evaluating TES samples revealed a low prevalence of pfhrp2/3 deletions in most sites.

Topics: Antigens, Protozoan; Diagnostic Tests, Routine; Ethiopia; Gene Deletion; Humans; Kenya; Madagascar; Malaria; Malaria, Falciparum; Plasmodium falciparum; Protozoan Proteins; Rwanda

Rapid diagnostic tests (RDT) are widely used for malaria diagnosis in Madagascar, where Plasmodium falciparum is the predominant species. Molecular diagnosis is essential for malaria surveillance, but requires additional blood samples for DNA extraction. Used RDTs is an attractive alternative that can be used as a source of DNA. Plasmodium falciparum genetic diversity and multiplicity of infection, usually determined by the genotyping of polymorphic regions of merozoite surface proteins 1 and 2 genes (msp1, msp2), and the repeated region RII of the glutamate-rich protein gene (glurp) have been associated with malaria transmission levels and subsequently with the impact of the deployed control strategies. Thus, the study aims to use RDT as DNA source to detect Plasmodium species, to characterize Plasmodium falciparum genetic diversity and determine the multiplicity of infection.. A pilot study was conducted in two sites with different epidemiological patterns: Ankazomborona (low transmission area) and Matanga (high transmission area). On May 2018, used RDT (SD BIOLINE Malaria Ag P.f/Pan, 05FK63) were collected as DNA source. Plasmodium DNA was extracted by simple elution with nuclease free water. Nested-PCR were performed to confirm Plasmodium species and to analyse P. falciparum msp1, msp2 and glurp genes polymorphisms.. Amongst the 170 obtained samples (N = 74 from Ankazomborona and N = 96 from Matanga), Plasmodium positivity rate was 23.5% (40/170) [95% CI 17.5-30.8%] by nested-PCR with 92.2% (37/40) positive to P. falciparum, 5% (2/40) to Plasmodium vivax and 2.5% (1/40) to P. falciparum/P. vivax mixed infection. Results showed high polymorphisms in P. falciparum msp1, msp2 and glurp genes. Multiple infection rate was 28.6% [95% CI 12.2-52.3%]. The mean of MOI was 1.79 ± 0.74.. This pilot study highlighted that malaria diagnosis and molecular analysis are possible by using used malaria RDT. A large-scale study needs to be conducted to assess more comprehensively malaria parasites transmission levels and provide new data for guiding the implementation of local strategies for malaria control and elimination. Trial registration Retrospectively registered.

Topics: Antigens, Protozoan; DNA, Protozoan; Genetic Variation; Humans; Madagascar; Malaria, Falciparum; Merozoite Surface Protein 1; Pilot Projects; Plasmodium falciparum; Polymorphism, Genetic; Protozoan Proteins

Malaria is a parasitic disease caused by a hematozoan of the genus. A total of 142. The successful rates of amplification of. Despite the limited number of samples analyzed, our study highlighted the circulation of isolates carrying both the mutant

Topics: Amodiaquine; Artesunate; Child; Chloroquine; Drug Resistance; Genotype; Humans; Madagascar; Malaria, Falciparum; Membrane Transport Proteins; Multidrug Resistance-Associated Proteins; Plasmodium falciparum; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; Protozoan Proteins

Assessment of the genetic diversity of Plasmodium falciparum parasites from various malaria transmission settings could help to define tailored local strategies for malaria control and elimination. Such assessments are currently scarce in Madagascar. The study presented here aimed to bridge this gap by investigating the genetic diversity of P. falciparum populations in three epidemiological strata (Equatorial, Tropical and Fringes) in Madagascar.. Two-hundred and sixty-six P. falciparum isolates were obtained from patients with uncomplicated malaria enrolled in clinical drug efficacy studies conducted at health centres in Tsaratanana (Equatorial stratum), Antanimbary (Tropical stratum) and Anjoma Ramartina (Fringes) in 2013 and 2016. Parasite DNA was extracted from blood samples collected before anti-malarial treatment. Plasmodium species were identified by nested PCR targeting the 18 S rRNA gene. The genetic profiles of P. falciparum parasites were defined by allele-specific nested PCR on the polymorphic regions of the msp-1 and msp-2 genes.. Fifty-eight alleles were detected in the P. falciparum samples tested: 18 alleles for msp-1 and 40 for msp-2. K1 (62.9%, 139/221) and FC27 (69.5%, 114/164) were the principal msp-1 and msp-2 allele families detected, although the proportions of the msp-1 and msp-2 alleles varied significantly between sites. Polyclonal infections were more frequent at sites in the Equatorial stratum (69.8%) than at sites in the Tropical stratum (60.5%) or Fringes (58.1%). Population genetics analyses showed that genetic diversity was similar between sites and that parasite flow within sites was limited.. This study provides recent information about the genetic diversity of P. falciparum populations in three transmission strata in Madagascar, and valuable baseline data for further evaluation of the impact of the control measures implemented in Madagascar.

Topics: Genetic Variation; Madagascar; Malaria, Falciparum; Plasmodium falciparum

Malaria is still a heavy public health concern in Madagascar. Few studies combining parasitology and entomology have been conducted despite the need for accurate information to design effective vector control measures. In a Malagasy region of moderate to intense transmission of both Plasmodium falciparum and P. vivax, parasitology and entomology have been combined to survey malaria transmission in two nearby villages.. Community-based surveys were conducted in the villages of Ambohitromby and Miarinarivo at three time points (T1, T2 and T3) during a single malaria transmission season. Human malaria prevalence was determined by rapid diagnostic tests (RDTs), microscopy and real-time PCR. Mosquitoes were collected by human landing catches and pyrethrum spray catches and the presence of Plasmodium sporozoites was assessed by TaqMan assay.. Malaria prevalence was not significantly different between villages, with an average of 8.0% by RDT, 4.8% by microscopy and 11.9% by PCR. This was mainly due to P. falciparum and to a lesser extent to P. vivax. However, there was a significantly higher prevalence rate as determined by PCR at T2 ([Formula: see text] = 7.46, P = 0.025). Likewise, mosquitoes were significantly more abundant at T2 ([Formula: see text] = 64.8, P < 0.001), especially in Ambohitromby. At T1 and T3 mosquito abundance was higher in Miarinarivo than in Ambohitromby ([Formula: see text] = 14.92, P < 0.001). Of 1550 Anopheles mosquitoes tested, 28 (1.8%) were found carrying Plasmodium sporozoites. The entomological inoculation rate revealed that Anopheles coustani played a major contribution in malaria transmission in Miarinarivo, being responsible of 61.2 infective bites per human (ib/h) during the whole six months of the survey, whereas, it was An. arabiensis, with 36 ib/h, that played that role in Ambohitromby.. Despite a similar malaria prevalence in two nearby villages, the entomological survey showed a different contribution of An. coustani and An. arabiensis to malaria transmission in each village. Importantly, the suspected secondary malaria vector An. coustani, was found playing the major role in malaria transmission in one village. This highlights the importance of combining parasitology and entomology surveys for better targeting local malaria vectors. Such study should contribute to the malaria pre-elimination goal established under the 2018-2022 National Malaria Strategic Plan.

Topics: Animals; Anopheles; Disease Vectors; Madagascar; Malaria, Falciparum; Malaria, Vivax; Microscopy; Mosquito Vectors; Plasmodium falciparum; Plasmodium vivax; Polymerase Chain Reaction; Staining and Labeling

Malaria transmission in Madagascar is highly heterogeneous, exhibiting spatial, seasonal and long-term trends. Previous efforts to map malaria risk in Madagascar used prevalence data from Malaria Indicator Surveys. These cross-sectional surveys, conducted during the high transmission season most recently in 2013 and 2016, provide nationally representative prevalence data but cover relatively short time frames. Conversely, monthly case data are collected at health facilities but suffer from biases, including incomplete reporting and low rates of treatment seeking. We combined survey and case data to make monthly maps of prevalence between 2013 and 2016. Health facility catchment populations were estimated to produce incidence rates from the case data. Smoothed incidence surfaces, environmental and socioeconomic covariates, and survey data informed a Bayesian prevalence model, in which a flexible incidence-to-prevalence relationship was learned. Modelled spatial trends were consistent over time, with highest prevalence in the coastal regions and low prevalence in the highlands and desert south. Prevalence was lowest in 2014 and peaked in 2015 and seasonality was widely observed, including in some lower transmission regions. These trends highlight the utility of monthly prevalence estimates over the four year period. By combining survey and case data using this two-step modelling approach, we were able to take advantage of the relative strengths of each metric while accounting for potential bias in the case data. Similar modelling approaches combining large datasets of different malaria metrics may be applicable across sub-Saharan Africa.

Topics: Bayes Theorem; Cross-Sectional Studies; Health Surveys; Humans; Madagascar; Malaria, Falciparum; Plasmodium falciparum; Population Surveillance; Prevalence; Spatio-Temporal Analysis

Malaria is one of the primary health concerns in Madagascar. Based on the duration and intensity of transmission, Madagascar is divided into five epidemiological strata that range from low to mesoendemic transmission. In this study, the spatial and temporal dynamics of malaria within each epidemiological zone were studied.. The number of reported cases of uncomplicated malaria from 112 health districts between 2010 and 2014 were compiled and analysed. First, a Standardized Incidence Ratio was calculated to detect districts with anomalous incidence compared to the stratum-level incidence. Building on this, spatial and temporal malaria clusters were identified throughout the country and their variability across zones and over time was analysed.. The incidence of malaria increased from 2010 to 2014 within each stratum. A basic analysis showed that districts with more than 50 cases per 1000 inhabitants are mainly located in two strata: East and West. Lower incidence values were found in the Highlands and Fringe zones. The standardization method revealed that the number of districts with a higher than expected numbers of cases increased through time and expanded into the Highlands and Fringe zones. The cluster analysis showed that for the endemic coastal region, clusters of districts migrated southward and the incidence of malaria was the highest between January and July with some variation within strata.. This study identified critical districts with low incidence that shifted to high incidence and district that were consistent clusters across each year. The current study provided a detailed description of changes in malaria epidemiology and can aid the national malaria programme to reduce and prevent the expansion of the disease by targeting the appropriate areas.

Topics: Adolescent; Adult; Child; Child, Preschool; Cluster Analysis; Cohort Studies; Humans; Incidence; Infant; Infant, Newborn; Madagascar; Malaria, Falciparum; Spatio-Temporal Analysis; Young Adult

The Malagasy Ministry of Health aimed to achieve 80% coverage of intermittent preventive treatment of malaria among pregnant women (IPTp) in targeted districts by 2015. However, IPTp coverage rates of have remained fairly static over the past few years.. During a cross-sectional household survey, mothers of children under the age of 2 years were asked about their most recent pregnancy. The primary outcome of interest was a mother receiving two or more doses of sulfadoxine-pyrimethamine (SP) (IPTp2) during their last pregnancy, at least one of which was obtained from a health provider. Multilevel analysis was used to account for community-level factors. Correlates included exposure to communication messages, the number of antenatal care (ANC) visits made by the woman, her household wealth, and other sociodemographic characteristics.. Over one-tenth (11.7%) of women received two or more doses of SP, at least one of which was obtained during an ANC visit. Two-thirds (68.3%) of women who consulted a health provider but did not take IPTp attributed this to not being offered the medication by their health provider. The odds of a woman receiving IPTp2 varied with her knowledge, attitudes, and perceived social norms related to IPTp and ANC and exposure to malaria messages. General malaria ideation, specifically the perceived severity of and perceived susceptibility to malaria, however, was not associated with increased odds of receiving IPTp2. A large variation in the odds of receiving IPTp2 was due to community-level factors that the study did not examine.. Health communication programmes should aim to improve IPTp/ANC-specific ideation, particularly the norms of seeking regular care during pregnancy and taking any prescribed medication. While ANC attendance is necessary, it was not sufficient to meet IPTp2 coverage. Women surveyed in Madagascar rely on health providers to prescribe SP according to national policy. At the same time, stock-outs prevent health providers from prescribing SP. The large observed community-level variation in IPTp2 coverage is likely due to supply-side factors, such as SP availability and health-provider ideation and practices.

Topics: Adult; Antimalarials; Cross-Sectional Studies; Drug Combinations; Female; Humans; Madagascar; Malaria, Falciparum; Middle Aged; Patient Acceptance of Health Care; Plasmodium falciparum; Pregnancy; Pregnancy Complications, Parasitic; Pyrimethamine; Sulfadoxine; Young Adult

Reliable measures of disease burden over time are necessary to evaluate the impact of interventions and assess sub-national trends in the distribution of infection. Three Malaria Indicator Surveys (MISs) have been conducted in Madagascar since 2011. They provide a valuable resource to assess changes in burden that is complementary to the country's routine case reporting system.. A Bayesian geostatistical spatio-temporal model was developed in an integrated nested Laplace approximation framework to map the prevalence of Plasmodium falciparum malaria infection among children from 6 to 59 months in age across Madagascar for 2011, 2013 and 2016 based on the MIS datasets. The model was informed by a suite of environmental and socio-demographic covariates known to influence infection prevalence. Spatio-temporal trends were quantified across the country.. Despite a relatively small decrease between 2013 and 2016, the prevalence of malaria infection has increased substantially in all areas of Madagascar since 2011. In 2011, almost half (42.3%) of the country's population lived in areas of very low malaria risk (<1% parasite prevalence), but by 2016, this had dropped to only 26.7% of the population. Meanwhile, the population in high transmission areas (prevalence >20%) increased from only 2.2% in 2011 to 9.2% in 2016. A comparison of the model-based estimates with the raw MIS results indicates there was an underestimation of the situation in 2016, since the raw figures likely associated with survey timings were delayed until after the peak transmission season.. Malaria remains an important health problem in Madagascar. The monthly and annual prevalence maps developed here provide a way to evaluate the magnitude of change over time, taking into account variability in survey input data. These methods can contribute to monitoring sub-national trends of malaria prevalence in Madagascar as the country aims for geographically progressive elimination.

Topics: Child, Preschool; Female; History, 21st Century; Humans; Infant; Madagascar; Malaria; Malaria, Falciparum; Male; Plasmodium falciparum; Prevalence; Surveys and Questionnaires

Community prevalence of infection is a widely used, standardized metric for evaluating malaria endemicity. Conventional methods for measuring prevalence include light microscopy and rapid diagnostic tests (RDTs), but their detection thresholds are inadequate for diagnosing low-density infections. The significance of submicroscopic malaria infections is poorly understood in Madagascar, a country of heterogeneous malaria epidemiology. A cross-sectional community survey in the western foothills of Madagascar during the March 2014 transmission season found malaria infection to be predominantly submicroscopic and asymptomatic. Prevalence of

Topics: Adolescent; Adult; Asymptomatic Diseases; Child; Child, Preschool; Cross-Sectional Studies; Duffy Blood-Group System; Female; Gene Expression; Health Surveys; Humans; Infant; Madagascar; Malaria, Falciparum; Malaria, Vivax; Male; Microscopy; Plasmodium falciparum; Plasmodium vivax; Polymerase Chain Reaction; Prevalence; Receptors, Cell Surface; Risk Factors; Rural Population

Topics: Adult; Antimalarials; Artemisinins; Bone Marrow; Drug Therapy, Combination; Endemic Diseases; Female; Humans; Lactones; Lymphohistiocytosis, Hemophagocytic; Madagascar; Malaria, Falciparum; Remission Induction; Travel-Related Illness

Although malaria has been traditionally regarded as less of a problem in urban areas compared to neighbouring rural areas, the risk of malaria infection continues to exist in densely populated, urban areas of Africa. Despite the recognition that urbanization influences the epidemiology of malaria, there is little consensus on urbanization relevant for malaria parasite mapping. Previous studies examining the relationship between urbanization and malaria transmission have used products defining urbanization at global/continental scales developed in the early 2000s, that overestimate actual urban extents while the population estimates are over 15 years old and estimated at administrative unit level.. This study sought to discriminate an urbanization definition that is most relevant for malaria parasite mapping using individual level malaria infection data obtained from nationally representative household-based surveys. Boosted regression tree (BRT) modelling was used to determine the effect of urbanization on malaria transmission and if this effect varied with urbanization definition. In addition, the most recent high resolution population distribution data was used to determine whether population density had significant effect on malaria parasite prevalence and if so, could population density replace urban classifications in modelling malaria transmission patterns. The risk of malaria infection was shown to decline from rural areas through peri-urban settlements to urban central areas. Population density was found to be an important predictor of malaria risk. The final boosted regression trees (BRT) model with urbanization and population density gave the best model fit (Tukey test p value <0.05) compared to the models with urbanization only.. Given the challenges in uniformly classifying urban areas across different countries, population density provides a reliable metric to adjust for the patterns of malaria risk in densely populated urban areas. Future malaria risk models can, therefore, be improved by including both population density and urbanization which have both been shown to have significant impact on malaria risk in this study.

Topics: Africa South of the Sahara; Child, Preschool; Female; Humans; Infant; Infant, Newborn; Madagascar; Malaria, Falciparum; Male; Plasmodium falciparum; Population Density; Prevalence; Regression Analysis; Urbanization

Deforestation and land-use change have the potential to alter human exposure to malaria. A large percentage of Madagascar's original forest cover has been lost to slash-and-burn agriculture, and malaria is one of the top causes of mortality on the island. In this study, the influence of land-use on the distribution of Plasmodium vectors and concomitant Plasmodium infection in humans and mosquito vectors was examined in the southeastern rainforests of Madagascar.. From June to August 2013, health assessments were conducted on individuals living in sixty randomly selected households in six villages bordering Ranomafana National Park. Humans were screened for malaria using species-specific rapid diagnostic tests (RDTs), and surveyed about insecticide-treated bed net (ITN) usage. Concurrently, mosquitoes were captured in villages and associated forest and agricultural sites. All captured female Anopheline mosquitoes were screened for Plasmodium spp. using a circumsporozoite enzyme-linked immunosorbent assay (csELISA).. Anopheles spp. dominated the mosquito communities of agricultural and village land-use sites, accounting for 41.4 and 31.4 % of mosquitoes captured respectively, whereas Anopheles spp. accounted for only 1.6 % of mosquitoes captured from forest sites. Interestingly, most Anopheles spp. (67.7 %) were captured in agricultural sites in close proximity to animal pens, and 90.8 % of Anopheles mosquitoes captured in agricultural sites were known vectors of malaria. Three Anopheline mosquitoes (0.7 %) were positive for malaria (Plasmodium vivax-210) and all positive mosquitoes were collected from agricultural or village land-use sites. Ten humans (3.7 %) tested were positive for P. falciparum, and 23.3 % of those surveyed reported never sleeping under ITNs.. This study presents the first report of malaria surveillance in humans and the environment in southeastern Madagascar. These findings suggest that even during the winter, malaria species are present in both humans and mosquitoes; with P. falciparum found in humans, and evidence of P. vivax-210 in mosquito vectors. The presence of P. vivax in resident vectors, but not humans may relate to the high incidence of humans lacking the Duffy protein. The majority of mosquito vectors were found in agricultural land-use sites, in particular near livestock pens. These findings have the potential to inform and improve targeted malaria control and prevention strategies in the region.

Topics: Adolescent; Adult; Agriculture; Animals; Anopheles; Child; Child, Preschool; Conservation of Natural Resources; Female; Humans; Infant; Infant, Newborn; Madagascar; Malaria, Falciparum; Malaria, Vivax; Male; Plasmodium falciparum; Plasmodium vivax; Young Adult

Malaria remains a major public health problem in Madagascar. Widespread scale-up of intervention coverage has led to substantial reductions in case numbers since 2000. However, political instability since 2009 has disrupted these efforts, and a resurgence of malaria has since followed. This paper re-visits the sub-national stratification of malaria transmission across Madagascar to propose a contemporary update, and evaluates the reported routine case data reported at this sub-national scale.. Two independent malariometrics were evaluated to re-examine the status of malaria across Madagascar. First, modelled maps of Plasmodium falciparum infection prevalence (PfPR) from the Malaria Atlas Project were used to update the sub-national stratification into 'ecozones' based on transmission intensity. Second, routine reports of case data from health facilities were synthesized from 2010 to 2015 to compare the sub-national epidemiology across the updated ecozones over time. Proxy indicators of data completeness are investigated.. The epidemiology of malaria is highly diverse across the island's ecological regions, with eight contiguous ecozones emerging from the transmission intensity PfPR map. East and west coastal areas have highest transmission year-round, contrasting with the central highlands and desert south where trends appear more closely associated with epidemic outbreak events. Ecozones have shown steady increases in reported malaria cases since 2010, with a near doubling of raw reported case numbers from 2014 to 2015. Gauges of data completeness suggest that interpretation of raw reported case numbers will underestimate true caseload as only approximately 60-75 % of health facility data are reported to the central level each month.. A sub-national perspective is essential when monitoring the epidemiology of malaria in Madagascar and assessing local control needs. A robust assessment of the status of malaria at a time when intervention coverage efforts are being scaled up provides a platform from which to guide intervention preparedness and assess change in future periods of transmission.

Topics: Adolescent; Child; Child, Preschool; Communicable Disease Control; Disease Transmission, Infectious; Epidemiological Monitoring; Female; Humans; Incidence; Infant; Infant, Newborn; Madagascar; Malaria, Falciparum; Male; Topography, Medical

Encouraging advances in the control of Plasmodium falciparum malaria have been observed across much of Africa in the past decade. However, regions of high relative prevalence and transmission that remain unaddressed or unrecognized provide a threat to this progress. Difficulties in identifying such localized hotspots include inadequate surveillance, especially in remote regions, and the cost and labor needed to produce direct estimates of transmission. Genetic data can provide a much-needed alternative to such empirical estimates, as the pattern of genetic variation within malaria parasite populations is indicative of the level of local transmission. Here, genetic data were used to provide the first empirical estimates of P. falciparum malaria prevalence and transmission dynamics for the rural, remote Makira region of northeastern Madagascar.. Longitudinal surveys of a cohort of 698 total individuals (both sexes, 0-74 years of age) were performed in two communities bordering the Makira Natural Park protected area. Rapid diagnostic tests, with confirmation by molecular methods, were used to estimate P. falciparum prevalence at three seasonal time points separated by 4-month intervals. Genomic loci in a panel of polymorphic, putatively neutral markers were genotyped for 94 P. falciparum infections and used to characterize genetic parameters known to correlate with transmission levels.. Overall, 27.8% of individuals tested positive for P. falciparum over the 10-month course of the study, a rate approximately sevenfold higher than the countrywide average for Madagascar. Among those P. falciparum infections, a high level of genotypic diversity and a high frequency of polygenomic infections (68.1%) were observed, providing a pattern consistent with high and stable transmission.. Prevalence and genetic diversity data indicate that the Makira region is a hotspot of P. falciparum transmission in Madagascar. This suggests that the area should be highlighted for future interventions and that additional areas of high transmission may be present in ecologically similar regions nearby.

Topics: Adolescent; Adult; Aged; Child; Child, Preschool; Disease Transmission, Infectious; Female; Genetic Variation; Genotype; Genotyping Techniques; Humans; Infant; Infant, Newborn; Longitudinal Studies; Madagascar; Malaria, Falciparum; Male; Middle Aged; Molecular Epidemiology; Plasmodium falciparum; Prevalence; Rural Population; Young Adult

Field investigations highlighted the use of Psidium acutangulum Mart. ex DC (syn. P. persoonii McVaugh), a small tree used by the Wayana Amerindians in Twenke-Taluhwen and Antecume-Pata, French Guiana, for the treatment of malaria, and administered either orally in the form of a decoction or applied externally over the whole body. This use appears limited to the Wayana cultural group in French Guiana and has never been reported anywhere else. Our goal was to evaluate the antimalarial and anti-inflammatory activities of a P. acutangulum decoction to explain the good reputation of this remedy.. Interviews with the Wayana inhabitants of Twenke-Taluhwen and Antecume-Pata were conducted within the TRAMAZ project according to the TRAMIL methodology, which is based on a quantitative and qualitative analysis of medicinal plant uses. A decoction of dried aerial parts of P. acutangulum was prepared in consistency with the Wayana recipe. In vitro antiplasmodial assays were performed on chloroquine-resistant FcB1 ([(3)H]-hypoxanthine bioassay) and 7G8 (pLDH bioassay) P. falciparum strains and on chloroquine sensitive NF54 ([(3)H]-hypoxanthine bioassay) P. falciparum strain. In vitro anti-inflammatory activity (IL-1β, IL-6, IL-8, TNFα) was evaluated on LPS-stimulated human PBMC and NO secretion inhibition was measured on LPS stimulated RAW murine macrophages. Cytotoxicity of the decoction was measured on L6 mammalian cells, PBMCs, and RAW cells. A preliminary evaluation of the in vivo antimalarial activity of the decoction, administered orally twice daily, was assessed by the classical four-day suppressive test against P. berghei NK65 in mice.. The decoction displayed a good antiplasmodial activity in vitro against the three tested strains, regardless to the bioassay used, with IC50 values of 3.3µg/mL and 10.3µg/mL against P. falciparum FcB1 and NF54, respectively and 19.0µg/mL against P. falciparum 7G8. It also exhibited significant anti-inflammatory activity in vitro in a dose dependent manner. At a concentration of 50µg/mL, the decoction inhibited the secretion of the following pro-inflammatory cytokines: TNFα (-18%), IL-1β (-58%), IL-6 (-32%), IL-8 (-21%). It also exhibited a mild NO secretion inhibition (-13%) at the same concentration. The decoction was non-cytotoxic against L6 cells (IC50>100µg/mL), RAW cells and PBMC. In vivo, 150µL of the decoction given orally twice a day (equivalent to 350mg/kg/day of dried extract) inhibited 39.7% average parasite growth, with more than 50% of inhibition in three mice over five. The absence of response for the two remaining mice, however, induced a strong standard deviation.. This study highlighted the in vitro antiplasmodial activity of the decoction of P. acutangulum aerial parts, used by Wayana Amerindians from the Upper-Maroni in French Guiana in case of malaria. Its antioxidant and anti-inflammatory potential, which may help to explain its use against this disease, was demonstrated using models of artificially stimulated cells.

Topics: Animals; Anti-Inflammatory Agents; Antimalarials; Antiprotozoal Agents; Cell Line; Chloroquine; Ethnopharmacology; French Guiana; Humans; Interleukins; Leukocytes, Mononuclear; Malaria, Falciparum; Mice; Myrtaceae; Nitric Oxide; Plant Extracts; Plants, Medicinal; Plasmodium falciparum; Psidium; Tumor Necrosis Factor-alpha

Numerous studies have indicated a strong association between amplification of the multidrug resistance-1 gene and in vivo and in vitro mefloquine resistance of Plasmodium falciparum. Although falciparum infection usually is not treated with mefloquine, incorrect diagnosis, high frequency of undetected mixed infections, or relapses of P. vivax infection triggered by P. falciparum infections expose non-P. falciparum parasites to mefloquine. To assess the consequences of such unintentional treatments on P. vivax, we studied variations in number of Pvmdr-1 (PlasmoDB accession no. PVX_080100, NCBI reference sequence NC_009915.1) copies worldwide in 607 samples collected in areas with different histories of mefloquine use from residents and from travelers returning to France. Number of Pvmdr-1 copies correlated with drug use history. Treatment against P. falciparum exerts substantial collateral pressure against sympatric P. vivax, jeopardizing future use of mefloquine against P. vivax. A drug policy is needed that takes into consideration all co-endemic species of malaria parasites.

Topics: Cambodia; Drug Resistance; French Guiana; Gene Expression Regulation; Humans; Madagascar; Malaria, Falciparum; Malaria, Vivax; Mefloquine; Multidrug Resistance-Associated Proteins; Plasmodium falciparum; Plasmodium vivax; Protozoan Proteins; Sudan

Data collected by the GeoSentinel Surveillance Network for 1,415 ill travelers returning from Indian Ocean islands during 1997-2010 were analyzed. Malaria (from Comoros and Madagascar), acute nonparasitic diarrhea, and parasitoses were the most frequently diagnosed infectious diseases. An increase in arboviral diseases reflected the 2005 outbreak of chikungunya fever.

Topics: Adolescent; Adult; Aged; Alphavirus Infections; Chikungunya Fever; Communicable Diseases, Emerging; Comoros; Dengue; Female; Foodborne Diseases; Humans; Incidence; Madagascar; Malaria, Falciparum; Male; Middle Aged; Schistosomiasis; Sentinel Surveillance; Travel; Young Adult

Post-malaria neurological syndrome is a rare complication of malaria. Typically, it occurs in case of severe malaria. Here we report a case in a Malagasy patient presenting a non-severe Plasmodium falciparum malaria complicated by post-malaria neurological syndrome. The management of such a syndrome is radically different from non-severe malaria. No specific treatment is needed.

Topics: Adolescent; Humans; Madagascar; Malaria, Cerebral; Malaria, Falciparum; Male; Nervous System Diseases; Plasmodium falciparum; Syndrome

Home management of malaria is recommended for prompt, effective antimalarial treatment in children less than five years of age. Compliance, safety, and effectiveness of the new fixed-dose artesunate-amodiaquine regimen used to treat suspected malaria were assessed in febrile children enrolled in a 24-month cohort study in two settings in Madagascar. Children with fever were asked to visit community health workers. Presumptive antimalarial treatment was given and further visits were scheduled for follow-up. The primary endpoint was the risk of clinical/parasitologic treatment failure. Secondary outcomes included fever/parasite clearance, change in hemoglobin levels, and frequency of adverse events. The global clinical cure rate was 98.4% by day 28 and 97.9% by day 42. Reported compliance was 83.4%. No severe adverse effects were observed. This study provides comprehensive data concerning the clinical cure rate obtained with artesunate-amodiaquine and evidence supporting the scaling up of home management of malaria.

Topics: Amodiaquine; Antimalarials; Artemisinins; Child, Preschool; Dose-Response Relationship, Drug; Drug Combinations; Female; Follow-Up Studies; Humans; Madagascar; Malaria, Falciparum; Male; Patient Compliance; Plasmodium falciparum; Retrospective Studies; Surveys and Questionnaires; Treatment Outcome

Topics: Adolescent; Anticoagulants; Antimalarials; Endemic Diseases; Extracorporeal Membrane Oxygenation; Health Services Accessibility; High-Frequency Ventilation; Humans; India; Madagascar; Malaria, Falciparum; Male; Patient Transfer; Quinine; Respiratory Distress Syndrome; Reunion; Trees

Recently, Plasmodium falciparum parasites bearing Pfdhfr I164L single mutation were found in Madagascar. These new mutants may challenge the use of antifolates for the intermittent preventive treatment of malaria during pregnancy (IPTp). Assays with transgenic bacteria suggested that I164L parasites have a wild-type phenotype for pyrimethamine but it had to be confirmed by testing the parasites themselves.. Thirty Plasmodium falciparum clinical isolates were collected in 2008 in the south-east of Madagascar. A part of Pfdhfr gene encompassing codons 6 to 206 was amplified by PCR and the determination of the presence of single nucleotide polymorphisms was performed by DNA sequencing. The multiplicity of infection was estimated by using an allelic family-specific nested PCR. Isolates that appeared monoclonal were submitted to culture adaptation. Determination of IC(50s) to pyrimethamine was performed on adapted isolates.. Four different Pfdhfr alleles were found: the 164L single mutant-type (N = 13), the wild-type (N = 7), the triple mutant-type 51I/59R/108N (N = 9) and the double mutant-type 108N/164L (N = 1). Eleven out 30 (36.7%) of P. falciparum isolates were considered as monoclonal infection. Among them, five isolates were successfully adapted in culture and tested for pyrimethamine in vitro susceptibility. The wild-type allele was the most susceptible with a 50% inhibitory concentration (IC(50)) < 10 nM. The geometric mean of IC(50) of the three I164L mutant isolates was 6-fold higher than the wild-type with 61.3 nM (SD = 3.2 nM, CI95%: 53.9-69.7 nM). These values remained largely below the IC(50) of the triple mutant parasite (13,804 nM).. The IC(50)s of the I164L mutant isolates were significantly higher than those of the wild-type (6-fold higher) and close from those usually reported for simple mutants S108N (roughly10-fold higher than wild type). Given the observed values, the determination of IC(50)s directly on parasites did not confirm what has been found on transgenic bacteria. The prevalence increase of the Pfdhfr I164L single mutant parasite since 2006 could be explained by the selective advantage of this allele under sulphadoxine-pyrimethamine pressure. The emergence of highly resistant alleles should be considered in the future, in particular because an unexpected double mutant-type allele S108N/I164L has been already detected.

Topics: Adult; Amino Acid Substitution; Antimalarials; DNA, Protozoan; Drug Resistance; Female; Humans; Inhibitory Concentration 50; Madagascar; Malaria, Falciparum; Mutation, Missense; Parasitic Sensitivity Tests; Plasmodium falciparum; Polymerase Chain Reaction; Pregnancy; Pyrimethamine; Sequence Analysis, DNA; Tetrahydrofolate Dehydrogenase

The combination of sulfadoxine-pyrimethamine is recommended for use as intermittent preventive treatment of malaria during pregnancy and is deployed in Africa. The emergence and the spread of resistant parasites are major threats to such an intervention. We have characterized the Plasmodium falciparum dhfr (pfdhfr) haplotypes and flanking microsatellites in 322 P. falciparum isolates collected from the Comoros Islands and Madagascar. One hundred fifty-six (48.4%) carried the wild-type pfdhfr allele, 19 (5.9%) carried the S108N single-mutation allele, 30 (9.3%) carried the I164L single-mutation allele, 114 (35.4%) carried the N51I/C59R/S108N triple-mutation allele, and 3 (1.0%) carried the N51I/C59R/S108N/I164L quadruple-mutation allele. Microsatellite analysis showed the introduction from the Comoros Islands of the ancestral pfdhfr triple mutant allele of Asian origin and its spread in Madagascar. Evidence for the emergence on multiple occasions of the I164L single-mutation pfdhfr allele in Madagascar was also obtained. Thus, the conditions required to generate mutants with quadruple mutations are met in Madagascar, representing a serious threat to current drug policy.

Topics: Alleles; Animals; Comoros; Dinucleotide Repeats; Drug Resistance; Female; Genes, Protozoan; Haplotypes; Humans; Madagascar; Malaria, Falciparum; Mutation; Plasmodium falciparum; Pregnancy; Pregnancy Complications, Parasitic; Protozoan Proteins; Tetrahydrofolate Dehydrogenase

Diagnosis of malaria cases depends on parasitological examination. Since 2006, the Department of Infectious Diseases at the Joseph Raseta Befelatanana University Hospital in Madagascar has been using the malaria rapid diagnostic test. The percentage of malaria cases (presumed or confirmed) in relation to the number of hospitalized patients has decreased. It was 23.4% in 2003, 10.3% in 2006 and 4.3% in 2008 (p<0.01532). To improve management of malaria cases and rationalize use of antimalarial agents, diagnosis should be confirmed by rapid diagnostic tests.

Topics: Humans; Madagascar; Malaria, Falciparum; Reagent Kits, Diagnostic; Registries

Molecular studies have demonstrated that mutations in the Plasmodium falciparum chloroquine resistance transporter gene (Pfcrt) play a major role in chloroquine resistance, while mutations in P. falciparum multidrug resistance gene (Pfmdr-1) act as modulator. In Madagascar, the high rate of chloroquine treatment failure (44%) appears disconnected from the overall level of in vitro CQ susceptibility (prevalence of CQ-resistant parasites <5%) or Pfcrt mutant isolates (<1%), strongly contrasting with sub-Saharan African countries. Previous studies showed a high frequency of Pfmdr-1 mutant parasites (>60% of isolates), but did not explore their association with P. falciparum chloroquine resistance. To document the association of Pfmdr-1 alleles with chloroquine resistance in Madagascar, 249 P. falciparum samples collected from patients enrolled in a chloroquine in vivo efficacy study were genotyped in Pfcrt/Pfmdr-1 genes as well as the estimation of the Pfmdr-1 copy number. Except 2 isolates, all samples displayed a wild-type Pfcrt allele without Pfmdr-1 amplification. Chloroquine treatment failures were significantly associated with Pfmdr-1 86Y mutant codon (OR = 4.6). The cumulative incidence of recurrence of patients carrying the Pfmdr-1 86Y mutation at day 0 (21 days) was shorter than patients carrying Pfmdr-1 86N wild type codon (28 days). In an independent set of 90 selected isolates, in vitro susceptibility to chloroquine was not associated with Pfmdr-1 polymorphisms. Analysis of two microsatellites flanking Pfmdr-1 allele showed that mutations occurred on multiple genetic backgrounds. In Madagascar, Pfmdr-1 polymorphism is associated with late chloroquine clinical failures and unrelated with in vitro susceptibility or Pfcrt genotype. These results highlight the limits of the current in vitro tests routinely used to monitor CQ drug resistance in this unique context. Gaining insight about the mechanisms that regulate polymorphism in Pfmdr1 remains important, particularly regarding the evolution and spread of Pfmdr-1 alleles in P. falciparum populations under changing drug pressure which may have important consequences in terms of antimalarial use management.

Topics: Alleles; Animals; Antimalarials; ATP-Binding Cassette Transporters; Chloroquine; DNA, Protozoan; Drug Resistance; Gene Dosage; Madagascar; Malaria, Falciparum; Membrane Transport Proteins; Microsatellite Repeats; Plasmodium falciparum; Polymorphism, Genetic; Prospective Studies; Protozoan Proteins; Rats; Risk Factors

Strains of Plasmodium falciparum genetically resistant to chloroquine (CQ) due to the presence of pfcrt 76T appear to have been recently introduced to the island of Madagascar. The prevalence of such resistant genotypes is reported to be low (< 3%) when evaluated by conventional PCR. However, these methods are insensitive to low levels of mutant parasites present in patients with polyclonal infections. Thus, the current estimates may be an under representation of the prevalence of the CQ-resistant P. falciparum isolates on the island. Previously, minority variant chloroquine resistant parasites were described in Malawian patients using an isotopic heteroduplex tracking assay (HTA), which can detect pfcrt 76T-bearing P. falciparum minority variants in individual patients that were undetectable by conventional PCR. However, as this assay required a radiolabeled probe, it could not be used in many resource-limited settings.. This study describes a digoxigenin (DIG)-labeled chemiluminescent heteroduplex tracking assay (DIG-HTA) to detect pfcrt 76T-bearing minority variant P. falciparum. This assay was compared to restriction fragment length polymorphism (RFLP) analysis and to the isotopic HTA for detection of genetically CQ-resistant parasites in clinical samples.. Thirty one clinical P. falciparum isolates (15 primary isolates and 16 recurrent isolates) from 17 Malagasy children treated with CQ for uncomplicated malaria were genotyped for the pfcrt K76T mutation. Two (11.7%) of 17 patients harboured genetically CQ-resistant P. falciparum strains after therapy as detected by HTA. RFLP analysis failed to detect any pfcrt K76T-bearing isolates.. These findings indicate that genetically CQ-resistant P. falciparum are more common than previously thought in Madagascar even though the fitness of the minority variant pfcrt 76T parasites remains unclear. In addition, HTAs for malaria drug resistance alleles are promising tools for the surveillance of anti-malarial resistance. The use of a non-radioactive label allows for the use of HTAs in malaria endemic countries.

Topics: Animals; Antimalarials; Child; Child, Preschool; Chloroquine; Drug Resistance; Gene Amplification; Genotype; Heteroduplex Analysis; Humans; Luminescent Measurements; Madagascar; Malaria, Falciparum; Membrane Transport Proteins; Nucleic Acid Heteroduplexes; Plasmodium falciparum; Point Mutation; Protozoan Proteins; Sensitivity and Specificity

Few data are available about severe malaria in Madagascar. Our aims were to describe epidemiological, clinical and therapeutic aspects of severe malaria in patients in Antananarivo. We conducted a retrospective study from 1 March 2006 to 31 March 2008 at the infectious disease department. We recorded 61 cases of severe malaria among 1,803 in patients. Sex ratio was 2 and average age was 35.3 years old. Three pregnant women were recorded among women (15.8%). Self-medication was registered in 23%. Among 35 patients who received first medical care, no one had parasitological examination. The treatment was inadequate for all patients (n = 19). Conscience impairment (65.6%), jaundice (24.6%), seizure (18%) and prostration (14.8%) were the major severe signs. Diagnosis was made 6.54 days after the onset of the disease. Mortality rate was 11.5%. Self-medication, inappropriate primary care and delayed diagnosis represented risk factors for severe malaria in our cohort.

Topics: Adult; Antimalarials; Consciousness Disorders; Early Diagnosis; Female; Hospital Mortality; Hospitals, University; Hospitals, Urban; Humans; Jaundice; Madagascar; Malaria, Falciparum; Male; Pregnancy; Pregnancy Complications, Infectious; Retrospective Studies; Seizures; Self Medication; Treatment Outcome; Young Adult

To investigate whether the severity of Plasmodium falciparum attack in endemic areas was associated with the multiplicity of infection (MOI) and/or with a particular genotype(s).. In two areas of different malaria transmission pattern in Madagascar (Sainte-Marie - mesoendemic and Tsiroanomandidy - hypoendemic) the number and the proportions of msp-2 genotypes within isolates were determined for each patient using a capillary electrophoresis genotyping method. DNA sequencing was performed to identify the msp-2 allelic family of dominant clones.. Eighty six uncomplicated and 33 severe cases were included in Sainte-Marie and 48 uncomplicated and 69 severe cases were included in Tsiroanomandidy. We found no association between the MOI and severity of malaria as the same mean number of msp-2 genotypes was found in isolates from uncomplicated and from severe malaria cases (3.72 and 3.73, respectively, P>0.05). The study of the association of dominant clones with clinical status showed no particular genotype or allelic family associated with malaria severity.. Severity of malaria was not associated with higher MOI in our study. Severity did not appear restricted to some particular genotypes either. On the contrary, severe malaria appeared to be caused by very common genotypes in the studied areas. More comprehensive explorations including immunity and genetic factors of the host are needed to acquire new information about this complex condition.

Topics: Adolescent; Adult; Aged; Alleles; Animals; Antigens, Protozoan; Child; Child, Preschool; Erythrocytes; Female; Genes, Protozoan; Genotype; Humans; Infant; Madagascar; Malaria, Falciparum; Male; Middle Aged; Plasmodium falciparum; Polymorphism, Genetic; Rural Health; Seasons; Sequence Analysis, DNA; Young Adult

We assessed the performance of two new commercially available rapid diagnostic tests (RDTs) for malaria (SD Bioline Malaria Ag Pf test and Ag Pf/Pan test) in 200 patients with uncomplicated malaria between August and October 2007 in Madagascar. Results of the two RDTs were compared with those obtained by microscopy and real-time polymerase chain reaction. The sensitivity and specificity for detection of Plasmodium falciparum were 93% and 98.9%, respectively, for the SD Bioline Malaria Ag Pf test and 92.9% and 98.9% for the SD Bioline Malaria Ag Pf/Pan test. The sensitivity of the SD Bioline Malaria Ag Pf/Pan test was much lower for detection of other species (63.6%). The sensitivity of the two new assays decreased to 77.3% at parasitemia levels < 100 parasites/microL for detection of P. falciparum.

Topics: Animals; Chromatography; Female; Humans; Madagascar; Malaria, Falciparum; Male; Plasmodium falciparum; Sensitivity and Specificity

Field and laboratory studies were carried out in October and November 2005 to provide a comparative evaluation of the performance of three rapid malaria detection tests, two of which were recently introduced (the CareStart Malaria test and the SD Malaria Antigen Bioline test) and the well-known OptiMAL-IT test. Compared with microscopy, the sensitivity of the three tests to detect Plasmodium falciparum malaria was 97% for the CareStart Malaria test, 89.4% for the SD Malaria Antigen Bioline test, and 92.6% for the OptiMAL-IT test. The three tests were less sensitive in detecting non-P. falciparum infections, and the sensitivity decreased at levels of parasitemiaor=100 parasites/microL.

Topics: Adolescent; Adult; Child; Child, Preschool; Female; Humans; Infant; Madagascar; Malaria, Falciparum; Male; Microscopy; Middle Aged; Reagent Kits, Diagnostic; Sensitivity and Specificity

We assessed the status of point mutations associated with chloroquine resistance in pfcrt codon 76 and in pfmdr1 codon 86 among Plasmodium falciparum isolates from symptomatic patients in 3 sites in Madagascar. The in vitro susceptibility of P. falciparum isolates to quinoline-containing drugs was also determined. All isolates (N = 117) successfully typed were pfcrt wild-type, except one from Tsiroanomandidy (1 of 27). However, 67.5% (95% CI: 58.2-75.9%) of these isolates contained mutant pfmdr1 86Y. The pfmdr1 N86Y mutation is associated with higher mefloquine susceptibility, but it did not affect the sensitivity of parasites to chloroquine or quinine. Our findings demonstrate that pfmdr1 mutant P. falciparum are prevalent in Madagascar and confirm the low prevalence of pfcrt mutant P. falciparum after 60 years of chloroquine use. They provide additional field-based evidence for increased mefloquine susceptibility in pfmdr1 mutant P. falciparum and are suggestive of the intrahost selection of pfmdr1 mutant parasites.

Topics: Amodiaquine; Animals; Antimalarials; Chloroquine; DNA, Protozoan; Drug Resistance; Humans; Inhibitory Concentration 50; Madagascar; Malaria, Falciparum; Mefloquine; Membrane Transport Proteins; Multidrug Resistance-Associated Proteins; Plasmodium falciparum; Point Mutation; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; Prevalence; Protozoan Proteins; Quinine; Rural Population

To determine risk for drug-resistant malaria parasites entering Madagascar from Comoros Islands, we screened travelers. For the 141 Plasmodium falciparum isolates detected by real-time PCR, frequency of mutant alleles of genes associated with resistance to chloroquine and pyrimethamine was high. International-level antimalarial policy and a regional antimalarial forum are needed.

Topics: Adult; Animals; Antimalarials; Child, Preschool; Chloroquine; Comoros; Drug Resistance, Multiple; Female; Humans; Madagascar; Malaria, Falciparum; Male; Plasmodium falciparum; Polymerase Chain Reaction; Pyrimethamine; Travel

The island of Madagascar, lying in the Indian Ocean approximately 250 miles from the African coast, has so far remained one of the few areas in the world without noticeable Plasmodium falciparum high-grade chloroquine (CQ) resistance. Here we report genotyping data on pfcrt in Madagascar. The pfcrt K76T mutation, which is critical for resistance to CQ, was detected in six (3.3%) of 183 P. falciparum isolates screened, within the mutant haplotypes CVIET and CVIDT. This is the first observation of pfcrt mutant parasites on the island. The current massive distribution of CQ for in-home management of fever in children will promote the dissemination of these mutant CQ-resistant parasites. In this context, genotyping of pfcrt remains a useful tool for CQ resistance surveillance as the prevalence of pfcrt mutations is far from saturation in Madagascar.

Topics: Animals; Antimalarials; Chloroquine; Codon; Drug Resistance; Female; Humans; Madagascar; Malaria, Falciparum; Membrane Transport Proteins; Plasmodium falciparum; Point Mutation; Population Surveillance; Pregnancy; Pregnancy Complications, Infectious; Protozoan Proteins

The study of urban malaria is an area undergoing rapid expansion, after many years of neglect. The problem of over-diagnosis of malaria, especially in low transmission settings including urban areas, is also receiving deserved attention. The primary objective of the present study was to assess the frequency of malaria among febrile outpatients seen in private and public primary care facilities of Antananarivo. The second aim was to determine, among the diagnosed malaria cases, the contribution of autochthonous urban malaria.. Two cross-sectional surveys in 43 health centres in Antananarivo in February 2003 (rainy season) and in July 2003 (dry season) were conducted. Consenting clinically suspected malaria patients with fever or history of fever in the past 48 hours were included. Malaria rapid diagnostic tests and microscopy were used to diagnose malaria. Basic information was collected from patients to try to identify the origin of the infection: autochthonous or introduced.. In February, among 771 patients, 15 (1.9%) positive cases were detected. Three malaria parasites were implicated: Plasmodium. falciparum (n = 12), Plasmodium vivax (n = 2) and Plasmodium. ovale (n = 1). Only two cases, both P. falciparum, were likely to have been autochthonous (0.26%). In July, among 739 blood smears examined, 11 (1.5%) were positive: P. falciparum (n = 9) and P. vivax (n = 2). Three cases of P. falciparum malaria were considered to be of local origin (0.4%).. This study demonstrates that malaria cases among febrile episodes are low in Antananarivo and autochthonous malaria cases exist but are rare.

Topics: Animals; Anopheles; Antigens, Protozoan; Child, Preschool; Cross-Sectional Studies; Female; Fever; Humans; Madagascar; Malaria; Malaria, Falciparum; Male; Plasmodium falciparum; Plasmodium ovale; Plasmodium vivax; Polymerase Chain Reaction; Prevalence; Protozoan Proteins; Seasons; Urban Population

Madagascar presents a large heterogeneity in terms of climate and altitude, which explains the uneven spread of malaria throughout the island. The capital, Antananarivo, counts more than one million inhabitants, altitude between 1250 and 1470 m, in an area where the transmission is low but malaria may cause deadly epidemic outbreaks. Numerous malaria cases are reported, without biological confirmation, and reliable data about urban malaria transmission are lacking. The " Institut Pasteur de Madagascar" together with the Malagasy Ministry of Health performed in 2003 a study about malaria transmission in Antananarivo. A prevalence survey of malaria among fever syndromes, with data collected from 43 urban dispensaries, showed that confirmed malaria cases represented only 2% of the total fever cases (15 cases out of 779 fever syndromes). The vast majority was imported from costal areas (13 cases out of 15), where malaria is hyperendemic. However, a local urban transmission was found for two patients and five other subjects identified during a proximity survey. Vectors A. arabiensis and A. funestus were found inside the patient houses, located in close proximity of flooded rice fields. Genetic analysis of P. falciparum strains allowed to distinguish three genotypes, aggregated by house. The analysis of parasite genome polymorphism proves here its validity for epidemic surveys in areas where malaria is unstable, with no premunition in the local urban population.

Topics: Adolescent; Adult; Child; Female; Humans; Madagascar; Malaria, Falciparum; Male; Middle Aged; Urban Health

Malaria transmission remains poorly documented in areas of low transmission. A study has been carried out over two consecutive years in Analamiranga, a village located at an altitude of 885m on the western edge of the Malagasy highlands, with the aim of generating and updating malariometric indexes for both mosquitoes and schoolchildren. In this village, no vector control measures were performed during the study period nor during previous decades. Mosquitoes were collected monthly when landing on human volunteers and in various resting-places. Blood samples were taken every 3 months from schoolchildren aged 6-12 years and microscopically examined. Of 7,480 mosquitoes collected on human subjects, 5,790 were anophelines. Ten anopheline species were represented and three of these, Anopheles funestus, Anopheles arabiensis and Anopheles mascarensis, accounted for 59.2% of the collection. Of these three species 4,640 were also collected in resting places. The proportion of mosquitoes fed on bovids was high; conversely, the anthropophilic rate (mosquitoes fed on human beings) was especially low: 31%, 7% and 1%, respectively, for A. funestus, A. arabiensis and A. mascarensis. The only confirmed malaria vector was A. funestus with a low sporozoite index (of 6,830 A. funestus, five were positive for Plasmodium falciparum and four for Plasmodium vivax). The annual entomological inoculation rate (number of bites of infected anophelines per adult person) was estimated at 2.49 with low variation over the 2 years. Overall, 909 thick blood smears were tested from blood samples taken from schoolchildren with 30.3% being malaria-positive. The four Plasmodium species infecting human subjects were detected in the following proportions: P. falciparum 78.9%, P. vivax 19.4%, Plasmodium malariae 1.0% and Plasmodium ovale 0.7%. The proportions of children who were infected with any Plasmodium ranged from 10.7% in February to 51.0% in September. Parasitemic children with fever (axillary temperature >37.5 degrees C) accounted for 16.4% of the children sampled. This study demonstrates that there are substantial parasitological consequences of even a relatively low entomological transmission and also recommends including exterior resting-places of mosquitoes in future spraying campaigns in the highlands of Madagascar.

Topics: Animals; Anopheles; Child; Female; Humans; Insect Vectors; Madagascar; Malaria; Malaria, Falciparum; Malaria, Vivax; Population Density; Prevalence; Rural Health; Seasons; Time Factors

Antananarivo, the capital of Madagascar, is located at an altitude of over 1,200 m. The environment at this altitude is not particularly favourable to malaria transmission, but malaria nonetheless remains a major public health problem. The aim of this study was to evaluate exposure to malaria in the urban population of Antananarivo, by measuring the specific seroprevalence of Plasmodium falciparum.. Serological studies specific for P. falciparum were carried out with an indirect fluorescent antibody test (IFAT). In a representative population of Antananarivo, 1,059 healthy volunteers were interviewed and serum samples were taken.. The seroprevalence of IgG+IgA+IgM was 56.1% and that of IgM was 5.9%. The major risk factor associated with a positive IgG+IgA+IgM IFAT was travel outside Antananarivo, whether in the central highlands or on the coast. The abundance of rice fields in certain urban districts was not associated with a higher seroprevalence.. Malaria transmission levels are low in Antananarivo, but seroprevalence is high. Humans come into contact with the parasite primarily when travelling outside the city. Further studies are required to identify indigenous risk factors and intra-city variations more clearly.

Topics: Adolescent; Adult; Animals; Antibodies, Protozoan; Child; Female; Humans; Immunoglobulin A; Immunoglobulin G; Immunoglobulin M; Madagascar; Malaria, Falciparum; Male; Middle Aged; Plasmodium falciparum; Seroepidemiologic Studies; Urban Health; Urban Population

Culturing fresh clinical isolates of P. falciparum and using the isotopic method, we tested separately chloroquine and isradipine--a calcium channel blocker--, and also the combination isradipine plus chloroquine. Tested wild isolates were chloroquine-sensitive. With regard to the combination isradipine/chloroquine, the isobolograms obtained indicate that isradipine antagonises chloroquine antiplasmodial activity. Taking into account these findings, we discuss the issues related to the calcium channel blocker molecules.

Topics: Animals; Antimalarials; Calcium Channel Blockers; Chloroquine; Drug Resistance; Drug Synergism; Humans; Isradipine; Madagascar; Malaria, Falciparum; Parasitic Sensitivity Tests; Plasmodium falciparum

Topics: Animals; Antimalarials; Comoros; Dose-Response Relationship, Drug; Drug Resistance; Humans; In Vitro Techniques; Madagascar; Malaria, Falciparum; Plasmodium falciparum

To monitor the sensitivity of Plasmodium falciparum to the drugs used to treat severe malaria and to prevent malaria in Comoros and Madagascar.. We used the in vitro isotopic method to test the sensitivity of P. falciparum to quinine, mefloquine and cycloguanil.. We tested fresh isolates of P. falciparum, collected from patients living in urban, suburban and rural areas and suffering from uncomplicated malaria in 2001, against at least one of the antimalarials cited above. In both countries all of the successfully tested isolates were sensitive to quinine (N = 243) and to cycloguanil (N = 67). The mean IC50 ranged from 85.7 to 133.7 nM for quinine. For cycloguanil, the mean IC50 ranged from 1.4 to 20.2 nM and the highest IC50 value (102.5 nM) was recorded in Comoros. Only 0.9% (1/110) of the informative isolates from Madagascar were mefloquine-resistant (0/18 in Comoros). The mefloquine mean IC50s were 8.2 nM, 14.1 nM and 11.6 nM respectively in the rural, suburban and urban areas of Madagascar, and 5.9 nM in Comoros. A positive correlation was found between quinine and mefloquine IC50s (N = 127, r = 0.48, p < 10(-6)), but in vitro mefloquine was 6-16 times more potent than quinine. No correlation was noticed between the activities of quinine and cycloguanil or between the activities of mefloquine and cycloguanil.. We therefore advocate the use of a full-course regimen of quinine, as recommended by the World Health Organisation (WHO), to treat above all severe malaria in Madagascar and Comoros. Our results also demonstrate that the use of mefloquine- and cycloguanil-based antimalarials is still justified to prevent malaria in both countries, mainly in the case of travellers.

Topics: Animals; Antimalarials; Comoros; Drug Resistance; Humans; In Vitro Techniques; Madagascar; Malaria, Falciparum; Mefloquine; Plasmodium falciparum; Proguanil; Quinine; Triazines

Intermittent preventive treatment (IPT) of pregnant women with sulfadoxine-pyrimethamine (SP) is being considered as a routine practice in Madagascar, mainly to decrease the risks of malaria-associated severe anaemia in the women, and of low birthweight in their babies. There is, however, relatively little information available on the efficacy of SP when used, in Madagascar, to treat cases of Plasmodium falciparum malaria. In a preliminary study, carried out in 2003 in the village of Saharevo, 36 uncomplicated cases were each treated with a standard dose of SP and with paracetamol and then followed up for 28 days. No case of therapeutic failure occurred and all the asexual parasitaemias cleared by day 3. It therefore appears that SP is effective against P. falciparum in Saharevo (and probably in the whole, rural district of Moramanga in which the village lies). This is an encouraging observation to make before IPT is initiated throughout the country.

Topics: Animals; Antimalarials; Child; Child, Preschool; Drug Combinations; Female; Humans; Madagascar; Malaria, Falciparum; Male; Parasitemia; Plasmodium falciparum; Pyrimethamine; Rural Health; Sulfadoxine; Treatment Outcome

One hundred and ninety plants, of which 51 are used to treat malaria in traditional medicine, were collected in five different ecosystems of Madagascar for a screening programme devoted to the search of naturally-occurring antimalarial compounds. Thirty-nine plants, of which 12 are used as herbal antimalarials, were found to display in vitro activity against Plasmodium falciparum with a median inhibitory concentration (IC50) lower than 5 microg/ml while 9 had an IC50 ranging from 5 to 7.5 microg/ml. Seventeen of them exhibited cytotoxic effects on murine P388 leukemia cells with an IC50 < 10 microg/ml. The biological activities were mostly located in the ethyl acetate fractions. Bioassay-directed fractionation is underway to isolate the active constituents.

Topics: Animals; Antimalarials; Humans; Inhibitory Concentration 50; Madagascar; Malaria, Falciparum; Medicine, Traditional; Parasitic Sensitivity Tests; Phytotherapy; Plant Extracts; Plants, Medicinal; Plasmodium falciparum

To investigate the mechanism of action of two antiplasmodial compounds, ellagic acid and 3,4,5-trimethoxyphenyl (6'-O-galloyl)-beta-D-glucopyranoside (TMPGG), we studied in vitro two metabolic reactions of intraerythrocytic parasites: the activity of recombinant plasmepsin II, one of the haemoglobin proteases, and the detoxification of haematin into beta-haematin. Both compounds inhibited plasmepsin II activity, but at concentrations ten-fold higher than those needed for inhibiting parasite growth. Moreover, ellagic acid inhibited the formation of beta-haematin, with an IC50 only 3-fold higher than that of chloroquine. These data suggest that the antiplasmodial activity of ellagic acid could be related to the inhibition of beta-haematin formation, whereas plasmepsin II does not represent the main target of the two compounds.

Topics: Animals; Antimalarials; Dose-Response Relationship, Drug; Ellagic Acid; Glucosides; Humans; Malaria, Falciparum; Myrtaceae; Parasitic Sensitivity Tests; Phytotherapy; Plant Bark; Plant Extracts; Plasmodium falciparum

Malaria is known as tazo or tazomoka in local terminology in Madagascar. Within the context of traditional practice, malaria (and/or malaria symptoms) is commonly treated by decoctions or infusions from bitter plants. One possible approach to the identification of new antimalarial drug candidates is to search for compounds that cure or prevent malaria in plants empirically used to treat malaria. Thus, it is worth documenting the ethnobotanical data, and testing the antiplasmodial activity of the extractive from plants.. We interviewed traditional healers, known locally as ombiasy, at Andasibe in the eastern, rainy part of Madagascar. We recorded details of the preparation and use of plants for medicinal purposes. We extracted five alkaloids from Z. tsihanimposa stem bark, and tested them in vitro against Plasmodium falciparum FCM29.. We found that traditional healers treat malaria with herbal remedies consisting of one to eight different plants. We identified and listed the medicinal plants commonly used to treat malaria. The plants used included a large number of species from different families. Zanthoxylum sp (Rutaceae) was frequently cited, and plants from this genus are also used to treat malaria in other parts of Madagascar. From the plant list, Zanthoxylum tsihanimposa, bitter plant endemic to Madagascar, was selected and examined. Five alkaloids were isolates from the stem bark of this plant, and tested in vitro against malaria parasite. The geometric mean IC50 values ranged from 98.4 to 332.1 micromolar. The quinoline alkaloid gamma-fagarine exhibited the strongest antiplasmodial activity.. The current use of plants for medicinal purposes reflects the attachment of the Malagasy people to their culture, and also a lack of access to modern medicine. The possible extrapolation of these in vitro findings, obtained with plant extracts, to the treatment of malaria and/or the signs evoking malaria is still unclear. If plants are to be used as sources of novel antimalarial compounds, we need to increase our knowledge of their empirical use to improve plant selection. In the hope of preserving useful resources, we should now gather and record ethnobotanical data in Madagascar, and should try to bridge the gaps between empirics and realism.

Topics: Animals; Antimalarials; Drug Prescriptions; Humans; Inhibitory Concentration 50; Madagascar; Malaria, Falciparum; Phytotherapy; Plant Preparations; Plants, Medicinal; Plasmodium falciparum

To alleviate the insufficient number of experienced medical teams invited to and accepting to monitor the effectiveness of drugs prescribed to patients with a diagnosis of uncomplicated malaria and to insure the surveillance of the susceptibility of P. falciparum to current antimalarials used in Madagascar, there is a need to draw a feasible study protocol carefully discussed with them. We carried out a preliminary study in two rural areas and assessed the efficacy of sulfadoxine-pyrimethamine (SP) for curing uncomplicated P. falciparum malaria, with a simplified protocol based on the principle of observational study. A single dose of SP was given on day 0 with paracetamol. The persons to whom the drugs were administered accepted two other interventions of one member of the medical teams on day 14 and day 28. Nineteen patients, 3-63 years old, fulfilled the follow-up. The efficacy of this combination was noted for the 19 persons. Our results show that P. falciparum strains are susceptible to SP. Since SP will be used in intermittent preventive treatment in pregnant women in Madagascar, one way to delay the occurrence of SP resistant parasites will be (a) to avoid massive use of SP for the non pregnant persons and (b) to monitor susceptibility of P. falciparum to SP as part of pilot studies using standard WHO protocol (which is not really easy for most of the peripheral health facilities--with the follow-up procedures with clinical examination and parasitological control at Days 0, 1, 2, 3, 7, 14, 21 and 28), and routinely with simplified protocol such as the analytical observational study illustrated in this present study. Limit and advantage of observational study are discussed.

Topics: Adolescent; Adult; Antimalarials; Child; Child, Preschool; Climate; Drug Administration Schedule; Drug Combinations; Drug Monitoring; Drug Resistance; Feasibility Studies; Female; Follow-Up Studies; Humans; Madagascar; Malaria, Falciparum; Male; Middle Aged; Observation; Parasitic Sensitivity Tests; Pyrimethamine; Research Design; Residence Characteristics; Rural Health; Sulfadoxine; Treatment Outcome

Topics: Animals; Anopheles; Child; DDT; Humans; Insect Vectors; Madagascar; Malaria, Falciparum; Mosquito Control; Plasmodium falciparum; World Health Organization

Malaria transmission in the central highlands of Madagascar was interrupted in the 1960s by a national control program that used DDT indoor spraying and mass treatment with chloroquine. At the end of the 1980s in this region, epidemic malaria reappeared. Italian health authorities provided technical assistance to the National Malaria Control Program since the beginning of the resurgence of malaria in the central highlands. Yearly residual house spraying performed for 5 years (1993-1998) and the availability of antimalarial drugs reduced malaria transmission to very low levels, with improvement in parasitologic and entomologic indexes. A significant reduction of malaria prevalence was observed in the villages located at altitudes of 1,000-1,500 m, corresponding to the stratum of unstable malaria that was the main target of the antivector interventions. A significant reduction of malaria prevalence was also observed in the villages located at altitudes of 900-1,000 m, where malaria transmission is stable. The main vector Anopheles funestus was dramatically reduced in abundance and distribution in the sprayed areas.

Topics: Adolescent; Altitude; Animals; Anopheles; Child; Child, Preschool; Cohort Studies; DDT; Humans; Insect Vectors; Madagascar; Malaria, Falciparum; Mosquito Control; Parasitemia; Plasmodium falciparum; Prospective Studies; Rural Population

The dissemination of mutant and resistant strains of Plasmodium falciparum makes a considerable contribution to the spread of drug-resistant malaria. Populations around harbours and airports could be particularly exposed to Plasmodium isolates introduced with imported cases of malaria. The use of chloroquine as well as the use of and sulfadoxine/pyrimethamine is currently an effective method for treating uncomplicated cases of malaria in Madagascar. As part of a monitoring programme, in vitro methods were used to assess the sensitivity of P. falciparum isolates in two coastal towns in Madagascar: Mahajanga on the west coast and Toamasina on the east coast. All of the isolates from both sites were sensitive to amodiaquine, quinine, pyrimethamine and cycloguanil. All of the isolates from Mahajanga were sensitive to chloroquine (n = 25; mean IC50 = 22.6 nM, 95% confidence interval: 16.8-28.7 nM), whereas three of the isolates from Toamasina were resistant to chloroquine (n = 18; mean IC50 = 66.3 nM; 95% confidence interval: 42.6-90 nM). The frequency of the Pfcrt Thr-76 and the dhfr Asn-108 mutations was estimated by PCR/RFLP. The 43 P. falciparum isolates examined, including the three in vitro chloroquine-resistant isolates from Toamasina were all wild-type (Lys-76). Phenotyping and genotyping studies suggested that the prevalence of chloroquine- and pyrimethamine-resistant isolates and of mutant strains of P. falciparum is very low. These results showed that in vitro test and genotyping of resistance markers approaches could be successfully used to monitor the emergence of drug-resistant malaria and to try to alleviate the lack of medical teams able to carry out in vivo test. The possible hazard/risk associated with imported cases of malaria is discussed.

Topics: Animals; Antimalarials; Chloroquine; DNA, Protozoan; Drug Resistance; Drug Resistance, Multiple; Drug Therapy, Combination; Genotype; Humans; Madagascar; Malaria, Falciparum; Membrane Proteins; Membrane Transport Proteins; Mutation; Parasitic Sensitivity Tests; Phenotype; Plasmodium falciparum; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; Protozoan Proteins; Pyrimethamine; Sulfadoxine

To establish a simple definition of a malaria attack based on blood parasite density and other explanatory covariates, a cohort study was conducted from 1993 to 1996 in the Madagascar highlands undergoing a low seasonal transmission of falciparum malaria. Using logistic regression, the explanatory variables found to be significantly related to the risk of fever are parasite density, age, season, and year. However, and in contrast with other studies, we found no evidence of a clear cutoff in parasite density values consistent with the concept of "pyrogenic threshold" despite a gradual increase of the risk of fever with increasing parasite density. Furthermore, the model evidenced an individual-dependent relationship at a given age. This point was in accordance with the immunological data recorded from the participants. The investigators conclude that the parasite density to distinguish malaria attacks from other causes of fever is not reliable in a context of low falciparum transmission.

Topics: Adolescent; Adult; Age Factors; Aged; Animals; Body Temperature; Child; Child, Preschool; Disease Susceptibility; Female; Fever; Humans; Infant; Madagascar; Malaria, Falciparum; Male; Middle Aged; Odds Ratio; Plasmodium falciparum; Prevalence; Seasons

To determine how sensitive Plasmodium falciparum is to the major antimalarial drugs in Madagascar.. Assessment of Plasmodium falciparum isolates sensitivity to antimalarials, by use of the in-vitro radioisotope method.. Ankazobe and Saharevo in the foothill areas; and Toamasina and Tolagnaro in the coastal areas (between January 1998 and November 1999).. Primary Plasmodium falciparum isolates from patients with uncomplicated malaria attack.. Between January 1998 and November 1999, of the 293 in-vitro tests done with at least one antimalarial, 70% (205/293) were interpretable. As there was no significant difference between results from the four study sites, the data have been expressed as a whole. All of the successfully tested isolates were sensitive to halofantrine (n = 56) and to quinine (n = 199), 5.8% (12/205) of the isolates were resistant to chloroquine and 2% (4/199) to mefloquine. The geometric mean IC50 was 0.3 microg/L for halofantrine (95% CI = 0.1-0.4 microg/L); 9.4 microg/L for chloroquine (95% CI = 7.3-10.8 microg/L); 3.8 microg/L for mefloquine (95% CI = 3.3-4.3 microg/L); and 26.8 microg/L for quinine (95% CI = 24.3-29.4 microg/L). The low positive correlation found between halofantrine and chloroquine IC50s (n = 56; r = 0.41, P = 0.002) suggests a risk of cross-resistance between these two drugs.. The degree and frequency of chloroquine resistance in-vitro is stationary in Madagascar compared to previous results during the last decade. The in-vitro sensitivity of P. falciparum to quinine, mefloquine and halofantrine encourages the use of these drugs as alternative in case of chloroquine treatment failure. Nevertheless, it is important to maintain and to extend malaria and drug sensitivity surveillance in Madagascar.

Topics: Animals; Antimalarials; Chloroquine; Drug Evaluation, Preclinical; Drug Resistance; Hospitals, Public; Hospitals, Urban; Humans; Madagascar; Malaria, Falciparum; Mefloquine; Microbial Sensitivity Tests; Phenanthrenes; Plasmodium falciparum; Quinine; Rural Health

Cultivation of Plasmodium falciparum has been a major research success, leading to a greater understanding of the parasite. Despite the fact that several P. falciparum clones have been maintained in continuous culture in different laboratories, research in genomics and proteomics would require parasitic material produced from fresh wild isolates. We have tested the effect of the supernatant from primary culture of mice hepatocytes on in vitro growth of P. falciparum isolates. Parasitized blood samples were collected from Madagascan malarious patients naturally infected. Isolates proliferation was assessed by use of isotopic method. The asexual erythrocytic stages of P. falciparum were grown for 42 hours in RPMI 1640-based medium plus L15 medium-based supernatant from mice liver cells culture, and in standard RPMI 1640-based medium alone. The mean of parasite growth was 1.5 times greater when the standard medium was enriched with the liver cells layer supernatant at a proportion of 10% and 15% (v/v). The usefulness of P. falciparum ex-vivo culture and of the hepatocytes in vitro primary culture is discussed.

Topics: Animals; Cell Culture Techniques; Cell Division; Culture Media, Conditioned; Culture Media, Serum-Free; Genomics; Hepatocytes; Humans; Madagascar; Malaria, Falciparum; Mice; Organic Chemicals; Plasmodium falciparum; Proteomics; Time Factors

To redefine strategy and policy to cure or to prevent malaria, there is a need to get relevant and updated data on Plasmodium sp sensitivity level to antimalarial drugs. Thus, in September 1999, the Madagascan Ministry of Health and the Institut Pasteur de Madagascar (IPM) formed a network named RER for malaria resistance surveillance. To alleviate the lack of experienced medical teams within the health centres, and due to technical and logistic matters, as part of the network activities, it was decided to give a start with the in vitro studies which are carried out at IPM. In vitro sensitivity testing is done by use of the isotopic method. Results from the study done in 2001 demonstrate that the Madagascan P. falciparum isolates are susceptible to amodiaquine (n = 215), to cycloguanil (n = 56), to pyrimethamine (n = 98) and to quinine (n = 214). One isolate (1/110 i.e. 0.9%) of mefloquine-resistant phenotype is detected from the Eastern region. P. falciparum susceptibility to chloroquine is satisfactory with 95.4% (206/216) of in vitro sensitive isolates. RER arises from the partnership and collaboration between the Madagascan Ministry of Health and the IPM. The network set-up is presented. The usefulness of the in vivo approach, and the in vitro investigations (chemosusceptibility test and screening of mutations accounting for resistance to chloroquine) to monitor the emergence and the dissemination of drug-resistant parasites in Madagascar as well as in the subregion of the Indian Ocean is discussed.

Topics: Academies and Institutes; Animals; Antimalarials; Data Collection; DNA, Protozoan; Drug Resistance; Humans; Interinstitutional Relations; Madagascar; Malaria, Falciparum; Mutation; Needs Assessment; Parasitic Sensitivity Tests; Plasmodium falciparum; Population Surveillance; Public Health Practice

Chloroquine has been used in Madagascar since 1945 and remains the first-line treatment for uncomplicated cases of malaria. Low-grades of resistance type R1 and R2 have been reported. Thus, in vitro tests were performed in order to monitor the drug sensitivity of Plasmodium falciparum from different study sites, with the aim of identifying alternatives to chloroquine. Chloroquine IC50 values ranged from 0.2 nM to 283.4 nM (n = 190, mean IC50 = 52.6 nM; 95% CI = 46.1-59.1 nM). Fifteen isolates (7.9%) were chloroquine-resistant. One mefloquine-resistant isolate was detected (1/139). The test isolates were sensitive to amodiaquine (n = 118), quinine (n = 212), pyrimethamine (n = 86) and cycloguanil (n = 79). The median IC50 for amodiaquine was 12.3 nM (mean IC50 = 15.3 nM, 95% CI = 13.3-17.3 nM). Amodiaquine was 3.4 times as active as chloroquine in vitro and 7 times as active as quinine against P. falciparum. These results indicate that amodiaquine may be a potent alternative to chloroquine in Madagascar. There was positive correlation between tested quinoline-containing drugs activities, which suggests in vitro cross-susceptibility.

Topics: Amodiaquine; Animals; Antimalarials; Chloroquine; Drug Resistance; Drug Resistance, Multiple; Humans; Inhibitory Concentration 50; Madagascar; Malaria, Falciparum; Mefloquine; Parasitemia; Plasmodium falciparum; Proguanil; Pyrimethamine; Quinine; Triazines

Topics: Animals; Antimalarials; Chloroquine; Drug Resistance; Humans; Madagascar; Malaria, Falciparum; Membrane Proteins; Membrane Transport Proteins; Mutation; Parasitic Sensitivity Tests; Plasmodium falciparum; Protozoan Proteins

Although the national policy for malaria control in Madagascar is to use chloroquine as the first line of treatment, mefloquine has been and is recommended to travellers to the country, both for malaria prevention and cure. The in-vitro susceptibility of Plasmodium falciparum to mefloquine was therefore assessed during a prospective surveillance study in various areas in Madagascar, including the tourist sites of Nosy-be and Sainte Marie. Of the 254 isolates of P. falciparum successfully tested, 232 (90.9%) were sensitive to mefloquine, 12 (4.7%) showed decreased susceptibility (40 nM < IC50 < 50 nM), and 10 (3.9%) were resistant (IC50 > 50 nM). Five (50%) of the resistant strains and nine (75%) of those with decreased susceptibility were from coastal areas or the two tourist sites. The drug pressure that could have induced the resistance observed could therefore be related to the donation of antimalarials, such as mefloquine, by tourists to local populations. The residents of the coastal areas take any donated drugs as self-medication, ignoring recommended doses and durations of treatment. This situation has two main consequences: (1) there is an urgent need to control the abusive and incorrect use of antimalarial drugs in Madagascar, to safeguard the effectiveness of chemotherapy in the future; and (2) these increases in resistance compromise the efficiency of the antimalarial chemoprophylaxis currently recommended to tourists. The use of mefloquine can no longer be considered as a guarantee of protection against malaria in coastal areas and other sites frequented by tourists.

Topics: Animals; Antimalarials; Drug Administration Schedule; Drug Resistance; Endemic Diseases; Humans; Madagascar; Malaria, Falciparum; Mefloquine; Plasmodium falciparum; Prospective Studies; Public Health; Travel

For a better definition of the polymorphic features of Plasmodium falciparum parasite populations, the polymerase chain reaction (PCR) typing technique was used to investigate the genetic diversity and complexity of parasites harbored by acute P. falciparum carriers from three yet unexplored malaria-mesoendemic areas with different transmission levels: two localities in northwestern Brazil (Ariquemes and Porto Velho) and a village in Madagascar (Ankazobe). A total of 89 DNA samples were analyzed by amplification of polymorphic domains from genes encoding merozoite surface antigens 1 and 2 (MSP-1, MSP-2) and thrombospondin-related anonymous protein (TRAP) and by hybridization with allelic-family-specific probes or random-fragment-length polymorphism (RFLP). In all three localities, extensive polymorphism was observed for each marker, but the MSP-2 central repeat was the most diverse one. Similar levels of genetic diversity, allelic frequency, and infection complexity were observed in the two Brazilian localities, although the isolates had been sampled at 2-year intervals, suggesting the stability of the infecting parasite populations presenting in these regions of the Brazilian Amazon. Unexpectedly, although the entomologic inoculation rate was at least 3 times lower in Ankazobe than in the Brazilian areas. Malagasi samples appeared more complex than the Brazilian ones. The implications of these data with regard to parasite population-dynamics studies are discussed.

Topics: Animals; Antigens, Protozoan; Brazil; Endemic Diseases; Genetic Variation; Humans; Madagascar; Malaria, Falciparum; Merozoite Surface Protein 1; Polymorphism, Restriction Fragment Length; Protozoan Proteins

Chloroquine is still the drug of choice for first-line treatment of uncomplicated malaria in Madagascar. However development and spread of chloroquine-resistance could compromise this therapeutic strategy in the future. The purpose of this 1997 study was to compare the efficacy of combined treatment using sulfadoxine and pyrimethamine and single-agent treatment using chloroquine for management of uncomplicated malaria. Study data were collected at four sites in coastal areas of Madagascar where transmission of malaria is perennial. Prevalence of malaria ranged from 15 p. 100 to 22 p. 100 in school children and from 24 p. 100 to 72 p. 100 in outpatient consulting spontaneously at community health centers. All four Plasmodium species affecting man were identified. Plasmodium falciparum was involved in 83 p. 100 of cases. In vivo testing of the susceptibility of Plasmodium falciparum to chloroquine was performed in 149 patients according to the standard simplified 7-day protocol of the WHO. The 35 tests in school children demonstrated no evidence of resistance. However type R1 + R2 resistance was noted in 17 of the 114 tests performed on outpatients, i.e. 14.9 p. 100. In vitro testing demonstrated chloroquine resistance in four of the 90 specimens tested, i.e. 4.4 p. 100. With regard to combined sulfadoxine/pyrimethamine treatment, 45 of 46 in vivo tests in outpatients showed no evidence of resistance. Combination treatment was more effective than single-agent treatment (p = 0.02) and could offer an effective alternative for future use.

Topics: Adolescent; Animals; Child; Child, Preschool; Chloroquine; Drug Resistance; Drug Therapy, Combination; Humans; Madagascar; Malaria, Falciparum; Plasmodium falciparum; Pyrimethamine; Sulfadoxine

The Malagashy national malaria control programme ('Programme National de Lutte contre le Paludisme', PNLP) has been developing, since 1996, an epidemiological early warning system for malaria epidemics in the Central Highlands with the support of the Italian Development Cooperation. The system is based on the monitoring of malaria morbidity (clinical diagnosis) in 536 peripheral health centres (CSB) of the Highlands. The intervention area corresponds to 27 districts of the Antananarivo and Fianarantsoa provinces (4.7 million inhabitants) and spans around 100,000 square km. For each CSB a monthly warning threshold, defined as the 1993-1996 monthly mean number of malaria cases plus two standard deviations, was established. Three levels of epidemic alert have been defined according to the number of times the cases of presumptive malaria surpassed the threshold and according to the reported presence of severe malaria cases. The surveillance system relies also on the monitoring, in district hospitals of the Highlands, of the Plasmodium falciparum infection rate among clinically diagnosed malaria cases. A total of 185,589 presumptive malaria cases, corresponding to a 42/1000 malaria incidence, were recorded in 1997 by the surveillance system. During the same year 184 alerts of 2nd degree were reported. During 1998 173,632 presumptive malaria cases corresponding to a 38/1000 incidence were reported and 207 alerts of 2nd degree were detected; 75 of these alerts were investigated with ad hoc surveys and 3 initial malaria epidemics identified and controlled. Out of 6884 presumptive malaria cases diagnosed in the district hospitals during 1997-1998, only 835 (12.1%) have been confirmed by microscopy (P. falciparum 81.7%, P. vivax 15.0%, P. malariae 2.5%, P. ovale 0.2%, mixed infections 0.6%); 22.4% of these infections were imported cases from coastal endemic areas. The efficiency of the system in monitoring the trend of malaria morbidity and in the rapid detection and response to malaria epidemics is still being evaluated.

Topics: Animals; Disease Outbreaks; Humans; Incidence; Madagascar; Malaria, Falciparum; Plasmodium falciparum; Sentinel Surveillance

In Manarintsoa, near Antananarivo, Madagascar, two groups of patients were defined in terms of malaria clinical immune status: Group MA+ consisted of 36 patients who suffered from between one to four malaria attacks (MA) during the 20-week study, and Group MA- who comprised of 48 persons who did not have any malaria attacks during this time. In group MA+, IgM and IgG antibody levels to Plasmodium falciparum exoantigens (E-Ag) were inversely related to the number of malaria attacks. The level of IgM antibodies were significantly higher in group MA+. In contrast, IgG, IgG1, IgG2, IgG3 and IgG4 antibodies to E-Ag were significantly higher in group MA-. The level of IgG1 antibodies was inversely correlated, and IgG2 antibodies were positively correlated to the number of malaria attacks.

Topics: Adolescent; Adult; Antibodies, Protozoan; Antigens, Protozoan; Child; Humans; Immunoglobulin G; Longitudinal Studies; Madagascar; Malaria, Falciparum; Middle Aged; Multivariate Analysis; Periodicity; Prevalence; Statistics, Nonparametric

To investigate the relationships between predominant HLA class II alleles and immune responses to the Plasmodium falciparum ring-infected erythrocyte surface antigen (Pf155/RESA), 50 individuals from the highlands of Madagascar were followed-up from 1988 to 1991. The T cell reactivity and antibody responses to synthetic peptides (EENV)4, (EENVEHDA)4, and (DDEHVEEPTVA)3, representing major T and B epitopes of Pf155/RESA antigen, were assessed with an average of five determinations per individual over the four-year follow-up period. The T cell reactivity was investigated by lymphocyte proliferation and assays for interferon-gamma and interleukin-2 release. Antipeptide antibodies were measured using the Falcon assay screening test-enzyme-linked immunosorbent assay. The cumulative prevalence rates of cellular (range for the three peptides = 64-68%) and antibody responders (range = 70-74%) were similar for each peptide. The HLA class II typing was performed using polymerase chain reaction-restriction fragment length polymorphisms. The prevalent alleles or groups of alleles (frequency > 20%) were similar in responders and nonresponders, both for cellular and antibody responses to each peptide. These were HLA-DR 5 group and HLA-DQA1 *0601, *0101-0102-0104, HLA-DQB1 *0301, and HLA-DPB1 *0101-2601 alleles. Allelic distribution was similar in individuals presenting with (74%) or without (26%) a malaria attack during a 20-week follow-up conducted when malaria was hyperendemic (P > 0.05, by Fisher's exact test). Despite repeated immunologic measures that better identify the responders, no relationship was found between HLA class II alleles and the cellular or antibody responses to Pf155/RESA epitopes.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adolescent; Adult; Alleles; Amino Acid Sequence; Animals; Antibodies, Protozoan; Antigens, Protozoan; Antigens, Surface; Base Sequence; Child; DNA Primers; Epitopes; Female; Follow-Up Studies; Gene Frequency; HLA-D Antigens; Humans; Immunity, Cellular; Madagascar; Malaria, Falciparum; Male; Molecular Sequence Data; Plasmodium falciparum; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; Protozoan Proteins; T-Lymphocytes

To evaluate the ability of antibodies to Plasmodium falciparum ring-infected erythrocyte surface antigen (Pf155/RESA) epitopes to discriminate between individuals well protected or poorly protected against malaria, a receiver operating characteristic analysis was performed in two populations living in Madagascar and Malawi. The definition of protection was based on longitudinal measurements of clinical malarial attacks during the season of high malaria transmission in the Madagascar study, and on a cross-sectional measurement of parasitemia in the Malawi study. Antibodies to peptides reproducing the 4-mer, 8-mer, and 11-mer of the Pf155/RESA were tested for their reactivities using the Falcon assay screening test-enzyme-linked immunosorbent assay. Maximal detection of poorly protected individuals (specificity = 100%) corresponded to high cutoff antibody titers (range = 1.65-3.0 optical density [OD] units in the Madagascar study and 0.67-1.42 OD units in the Malawi study) and a sensitivity less than 50%. For a given sensitivity of 50%, specificity ranged from 55% to 62% in the Madagascar study, and from 67% to 94% in the Malawi study. The antibody cutoff titers corresponding to minimal misclassification rates ranged from 0.24 to 1.73 OD units in the Madagascar study and from 0.15 to 0.55 OD units in the Malawi study. For each antibody, the highest detectability value as measured by the area under the curve was obtained for anti-R11 in the Malawi study (0.838). In demonstrating such qualities, antibodies to Pf155/RESA epitopes could be used for screening poorly protected populations in which malaria control programs have to be implemented.

Topics: Amino Acid Sequence; Animals; Antibodies, Protozoan; Antigens, Protozoan; Cohort Studies; Enzyme-Linked Immunosorbent Assay; Epitopes; Female; Humans; Madagascar; Malaria, Falciparum; Malawi; Male; Molecular Sequence Data; Parasitemia; Plasmodium falciparum; Protozoan Proteins; ROC Curve; Sensitivity and Specificity

Topics: Antimalarials; Drug Costs; Drug Resistance; Humans; Madagascar; Malaria, Falciparum; Trimethoprim, Sulfamethoxazole Drug Combination

Topics: Antimalarials; Disease Outbreaks; Drug Resistance; Humans; Madagascar; Malaria, Falciparum; Population Surveillance; Risk Factors

Topics: Drug Resistance; Humans; Madagascar; Malaria, Falciparum; Population Surveillance; Residence Characteristics; Retrospective Studies; Risk Factors

To investigate the protective role of antibodies to the ring-infected erythrocyte surface antigen (Pf155/RESA) epitopes against Plasmodium falciparum clinical malaria, a cohort study was conducted in a Malagasy village over 7 months. In the 304 individuals included, 127 experienced P. falciparum attacks of under 1500 parasites/microliters with no clinical symptoms (protected individuals) and 177 experienced at least one clinical or preclinical P. falciparum attack requiring therapy (unprotected individuals). Antibodies to whole Pf155/RESA, to single epitopes of the 3' terminus, (EENV)4 and EENVEHDA(EENV)2 had higher responses in protected than in unprotected individuals (P = 0.006, P = 0.005, P = 0.05 respectively). Within the whole pattern of antibodies to the Pf155/RESA epitopes, only anti-R4 was related to protection independently of age and anti-wR. The Pf155/RESA 4-mer repeated epitope might be of interest for inclusion in a vaccine against the asexual blood stages of P. falciparum.

Topics: Adolescent; Adult; Amino Acid Sequence; Animals; Antibodies, Protozoan; Antigens, Protozoan; Antigens, Surface; Child; Child, Preschool; Cohort Studies; Epitopes; Follow-Up Studies; Humans; Incidence; Infant; Madagascar; Malaria, Falciparum; Molecular Sequence Data; Plasmodium falciparum; Prevalence; Protozoan Proteins

Authors record the results of entomological and paludometric studies which were run on July 1994 in Ampanihy (Southern Madagascar), since an epidemic of malaria occurred in that region. Although the risk of epidemic malaria is described in the Southern Madagascar, paludometric indexes found in these surveys are pertinent with a mesoendemic malaria. The entomological survey found. A gambiae complex and A. funestus. Complementary surveys are proposed to improve the knowledge of the epidemiology of malaria in this area.

Topics: Adolescent; Age Distribution; Animals; Anopheles; Child; Child, Preschool; Disease Outbreaks; Female; Humans; Infant; Infant, Newborn; Madagascar; Malaria, Falciparum; Malaria, Vivax; Male; Population Surveillance; Risk Factors; Severity of Illness Index

The authors describe the results of an entomological study run in December 1994 in the little town of Bezaha (South-Western Madagascar). The observed entomological indexes are those of an intensive malaria transmission area. The authors suggest to organize a longitudinal entomological survey along with a clinical and parasitological study. They also point out the fact that they found two microfilariae Wuchereria bancrofti in an Anopheles funestus female.

Topics: Animals; Anopheles; Circadian Rhythm; Feeding Behavior; Female; Humans; Insect Vectors; Madagascar; Malaria, Falciparum; Plasmodium falciparum; Population Surveillance; Reproduction; Urban Health; Wuchereria bancrofti

A longitudinal study on the prevalence of Plasmodium falciparum circumsporozoite antibodies (Ab-CS) was carried out in 15 villages of three epidemiologic areas of Madagascar: the highlands, east coast, and the southwest region. A total of 3,967 blood samples were collected from November 1989 to April 1991 from cohorts of resident schoolchildren. The prevalence of Ab-CS in the examined population varied greatly according to the different ecoepidemiologic areas of the country. A correlation analysis was made between Ab-CS and P. falciparum parasite prevalence in the same population. High Ab-CS prevalence rates (25-75%) and levels (optical density = 0.28-0.76) were observed in the villages of the east coast (mesoendemic stable malaria). The Ab-CS prevalence rates varied from 0 to 37% in the highlands and southwest region villages (unstable malaria). The use of Ab-CS prevalence is proposed to be a useful and reliable seroepidemiologic marker of malaria endemicity in those areas of Madagascar in which malaria transmission is high and continues for more than four months a year.

Topics: Adolescent; Animals; Antibodies, Protozoan; Antigens, Protozoan; Child; Cohort Studies; Geography; Humans; Longitudinal Studies; Madagascar; Malaria, Falciparum; Plasmodium falciparum; Prevalence; Protozoan Proteins; Seroepidemiologic Studies

Determine the sensitivity of the pathology examination of the placenta as a screening examination for malaria and the consequences of this infection on prematurity and birth-weight.. Eighty placentas were examined at the Mjunga, Madagascar dispensary at the beginning of the rainy season. The aspect of the placenta was compared with a malaria index and to malaria disease state as a function of parity and anti-malarial prophylaxis used by the mother as well as with the state of the infant.. Among the placentas examined, 41.3% were considered normal and abnormal or clearly pathological in 58.7%. Estimating the gestational age on the basis of the histological examination of the amniotic cells was in agreement with the gestational age calculated from the last cycle in 53 cases and in disagreement in 8 cases. The percentage of cases of malaria discovered by the pathology examination (20%) was greater than that after thick swab screening (10%). 75% of the mothers has Plasmodium falciparum infection at the time of delivery and 13.8% of the mothers with negative thick drops had malaria lesions of the placenta. The parity of infected mothers was similar to non infected mothers. All the premature newborns had pathological placentas included 12.5% with malarial lesions. 90% of the hypertrophic newborns had pathological placentas included 50% with malarial lesions. No case of congenital malaria was observed.. Pathology examination of the placenta is as sensitive as blood drop tests for screening for malaria. The histological examination of amniotic cells can give a good estimation of gestational age in developing countries.

Topics: Adolescent; Adult; Amnion; Birth Weight; Developing Countries; Female; Gestational Age; Humans; Hypertrophy; Infant, Newborn; Infant, Premature; Infant, Premature, Diseases; Madagascar; Malaria; Malaria, Falciparum; Mass Screening; Parity; Placenta; Placenta Diseases; Pregnancy; Pregnancy Complications, Parasitic; Sensitivity and Specificity; Social Class

Topics: Adult; Antimalarials; Drug Resistance, Microbial; Humans; Madagascar; Malaria, Falciparum; Male; Phenanthrenes

Crude alkaloids of Strychnos myrtoides Gilg & Busse, empirically used as an adjuvant to chloroquine (CQ) in Malagasy herbal remedies, were practically devoid of intrinsic in vitro and in vivo antimalarial activity. However, when combined with CQ at a dose level much lower than their IC50 value, they markedly enhanced in vitro the effectiveness of the synthetic drug against a CQ-resistant strain of Plasmodium falciparum. They also enhanced in vivo CQ activity against a resistant strain of Plasmodium yoelii. By counter-current distribution (CCD) separation of the crude alkaloid extract, the two major alkaloids strychnobrasiline (1) and malagashanine (2), together with four minor alkaloids, were isolated. Strychnobrasiline and malagashanine were devoid of both intrinsic antimalarial activity and cytotoxicity effect, but exhibited significant CQ-potentiating actions. These findings could account for the above-mentioned empirical use of S. myrtoides. The present state of research on antimalarial drug from Strychnos genus is also discussed.

Topics: Alkaloids; Animals; Antimalarials; Cell Line; Chloroquine; Drug Resistance; Drug Synergism; HeLa Cells; Humans; Madagascar; Malaria, Falciparum; Mice; Plants, Medicinal; Plasmodium falciparum; Plasmodium yoelii

We previously reported that antibodies to the central repeat (DDEHVEEPTVA) of Pf155/RESA, a major Plasmodium falciparum antigen, were negatively related to antimalarial protection. We measured levels of isotype antibodies to this epitope and to P. falciparum in 76 Madagascan subjects. Immunoglobulin G (IgG) and isotype antibodies specific for P. falciparum had similar levels in individuals who were considered protected and those who were not (as determined during a longitudinal follow-up). The levels of IgG1 antibodies to (DDEHVEEPTVA)3 were higher in nonprotected subjects. The levels of total IgG and of other isotype antibodies had a similar tendency to be higher in nonprotected than in protected individuals.

Topics: Amino Acid Sequence; Animals; Antibodies, Protozoan; Antibody Specificity; Epitopes; Humans; Immunoglobulin Isotypes; Madagascar; Malaria, Falciparum; Molecular Sequence Data; Peptides; Plasmodium falciparum

Results of the epidemiological surveillance of falciparum malaria carried out since 1987 in three villages of the malagasy Highlands are reported. They clearly show the unsteady endemo-epidemic characteristic of the disease with highly variable transmission levels according to foci. At Manarintsoa, a south-western village 20km away from the Capital, the disease has now fully disappeared after the ravage of 1986. But it might reappear with new imported cases and by lack of antivectorial measures. Although Anopheles arabiensis had been rare and its aggressivity rate weak (0.91-2 infecting bites per year per man), surveillance is indispensable for the future. An Ankazobe and Mahavelona, two north-western localities respectively 100km and 65km away from Antananarivo, malaria is endemic with periodic outbreaks during rainy season. At Ankazobe, Anopheles funestus is the main vector maintaining endemic in this area while the role of Anopheles gambiae l.s. is only secondary. At Mahavelona, because of the weak presence of vectors, the treatment protocol by Quinimax has been applied in order to study transmission. This study obviously shows that contrary to set ideas in the Highlands, backward transmission is possible up to the first months of the austral winter (June-July). In these two last villages, adults have acquired some premunition.

Topics: Adolescent; Adult; Altitude; Animals; Anopheles; Child; Disease Outbreaks; Humans; Incidence; Insect Vectors; Madagascar; Malaria, Falciparum; Morbidity; Population Surveillance; Prevalence; Quinine; Rain; Seasons; Suburban Population

Authors record the manifestations on the child of the severe malaria epidemic that raged in Antananarivo. Using the hospitalisation registers of the Debré room, Pediatric Service "A", at the Hospital of Befelatanana as source documents, they underline some points: Concerning morbidity, the epidemic started in 1984, reached its highest point in 1988 (26.7%, of in patients) and began to fade away in 1992. Boys and girls were equally affected, with a majority among children of 5 years old and more (51 to 58% of cases). All patients came from the center of Antananarivo (33.5%) or mainly from the surroundings (66.5%). At the highest point of the epidemic, about half of the children were suffering from severe malaria (48.9%). Plasmodium falciparum was the parasite responsible for 93.3% of cases. It seems that mortality is not influenced by sex, age or home but two factors are especially observed: nutrition disorders and delay of hospitalisation. The quinine based treatment has stemmed mortality by neuropaludism since two years.

Topics: Age Factors; Cause of Death; Child; Child Nutrition Disorders; Child, Preschool; Female; Hospitalization; Humans; Infant; Infant, Newborn; Madagascar; Malaria, Cerebral; Malaria, Falciparum; Male; Morbidity; Nutritional Status; Population Surveillance; Quinine; Time Factors; Urban Population

According to pharmaco-sensitivity studies, about 20% of local Plasmodium falciparum strains showed a certain degree of resistance to chloroquine. No resistance of R3 type has never been observed. During this whole period, the decrease of sensitivity phenomenon remains stable. Because of its remarkable action on parasitemia and fever, chloroquine remains the best antimalaria in simple malarial attacks in madagascar.

Topics: Animals; Chloroquine; Drug Resistance; Fever; Humans; Madagascar; Malaria, Falciparum; Plasmodium falciparum; Population Surveillance; Serotyping

Madagascar was one of the first African countries with reported chloroquine drug resistance of P. falciparum. Suspected as early as 1975, it was confirmed in 1981. Hereafter, regular tests in vivo and in vitro have been performed and allow for a study of drug resistance development. In 742 standard in vivo tests at the dose of 25 mg/kg of chloroquine that were executed between 1983 and 1993, R I resistance levels could be found in 8.5% of cases, R II was found in 8.2%. No resistance at R III levels was detected. The overall situation for in vitro is equally favorable. In 406 tests 78% of samples proved sensitive. The investigations undertaken by the Pasteur Institute of Madagascar, by the Institute for Tropical Medicine and Epidemiology in Paris and by the Unit of Epidemiological Surveillance within the Malagasy Ministry of Health raise a number of questions: Taking to account the various causes for imprecision in measurement and in evaluation (variations in parasite density, microscopic detection levels, bio-availability of the drug) of the groups of R I and R II how significant are the variations observed in numbers and proportions of resistance levels R I and R II? How important are the effects of auto-medication? Can they be correctly evaluated by Bergquist's test? How explain the low level of drug resistance in a country close to East Africa, in which chemoprophylaxis has been widely practiced and in which insufficient dosage for treatment is common? The absence of R III resistance in vivo permit for chloroquine to remain the first line treatment for malaria in Madagascar.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Bias; Biological Availability; Chloroquine; Drug Resistance; Humans; Madagascar; Malaria, Falciparum; Population Surveillance; Residence Characteristics; Self Medication

This study evaluated a nonisotopic DNA assay kit for diagnosing Plasmodium falciparum malaria in an area of Madagascar where all Plasmodium species of human malaria are present and where malaria is endemic. Blood samples from 440 healthy children and 20 healthy adults were processed and assayed in a single day in a blind protocol. The parasitemia levels of the four Plasmodium species were determined by microscopic examinations and by counts of numbers of malaria parasites per 1,000 white blood cells. Relative to P. falciparum infections, the DNA assay results agreed with those of microscopy for 207 positive and 239 negative samples; two samples were scored as positive by the DNA probe that were not detected by microscopy, and 12 samples were scored as positive by microscopy but were not detected by the assay. Relative to microscopy, the sensitivity of the assay was 95%, the specificity was 99%, and the effective sensitivity threshold of the DNA probe assay was approximately 30 parasites/mm3 of blood. The assay did not detect infections with either P. vivax, P. malariae, or P. ovale alone, but detected mixed infections of P. falciparum with either P. vivax or P. ovale. With this nonisotopic DNA probe assay, we were able to process large numbers of samples efficiently and to detect P. falciparum malaria infections with high sensitivity and specificity in a population that did not display overt disease symptoms.

Topics: Adolescent; Adult; Animals; Base Sequence; Child; Child, Preschool; DNA Probes; DNA, Protozoan; Evaluation Studies as Topic; Humans; Madagascar; Malaria, Falciparum; Molecular Sequence Data; Plasmodium falciparum; Reagent Kits, Diagnostic; Sensitivity and Specificity

A resurgence of falciparum malaria occurred in the central highlands of Madagascar in the 1980s and was responsible for an outbreak in 1986-1987. Since 1989, transmission has decreased dramatically. In April 1991, we investigated the humoral and cellular immune responses of 53 inhabitants of the village of Manarintsoa to six synthetic peptides that reproduced the major B and/or T cell epitopes of the Pfl 55/ring-infected erythrocyte surface antigen (RESA) of Plasmodium falciparum. The presence of RESA peptide-reactive T cells was assessed by lymphocyte proliferation assay as well as by detection of in vitro production of interferon-gamma and interleukin-2. The mean values of these cellular responses were low, and the results obtained in these three tests showed no correlation. Twenty-seven subjects presented with anti-RESA antibodies as detected by modified immunofluorescent assay, but the mean levels of anti-peptide antibodies were low. When compared with data obtained in January 1988 from the same subjects with three of the six peptides, the present data demonstrated a decrease in the response to these peptides in terms of both proliferative response and mean antibody titers. The mean values of anti-RESA antibodies remained unchanged. The fact that cellular and humoral responses to the major Pfl 55/RESA epitopes decreased but did not disappear probably reflects both the remainder of the acquired immunity resulting from the 1986-1987 malaria outbreak, and its conservation by the very low level of transmission since 1989.

Topics: Adolescent; Adult; Aged; Amino Acid Sequence; Animals; Antibodies, Protozoan; Antigens, Protozoan; Antigens, Surface; Female; Humans; Immunity, Cellular; Interferon-gamma; Interleukin-2; Lymphocyte Activation; Madagascar; Malaria, Falciparum; Male; Middle Aged; Molecular Sequence Data; Plasmodium falciparum; Prevalence; Protozoan Proteins; T-Lymphocytes

A study involving 169 schoolchildren (5-14 years old) living in Manarintsoa near Antananarivo (Madagascar, East Africa) was performed during the seasonal malaria transmission period. For the whole population examined, the prevalence of Plasmodium falciparum and the rates of spleen enlargement and of circulating stable antigen (S-Ag) were found to be 60.9%, 71.7%, and 46.8%, respectively. The prevalence of IgG antibody to RESA (ring-infected erythrocyte surface antigen) was 42.7% and that of IgG and IgM antibodies to E-Ag (exoantigens) was 44.9% and 2.9%, respectively. The positive rates for IgG and IgM antibodies to Som-Ag (somatic antigen) were 48.5% and 5.9%, respectively. Concerning S-Ag, no significant relationship was observed for parasitemia, spleen size, age, or IgM antibody responses to exoantigens (E-Ag) or to somatic antigen (Som-Ag). Levels of S-Ag were found to be related to IgG antibodies to E-Ag. Our results suggest that S-Ag at low levels may participate in the mechanisms involved in the development of the IgG antibody responses to E-Ag and to Som-Ag, whereas at a comparative population level, higher quantities of S-Ag down-regulate antibody responses to P. falciparum. The data we obtained were compared with those gathered in another malaria mesoendemic area (Bobo-Dioulasso, Burkina Faso, West Africa), where lower levels of S-Ag were found.

Topics: Adolescent; Age Factors; Animals; Antibody Formation; Antigens, Protozoan; Child; Child, Preschool; Enzyme-Linked Immunosorbent Assay; Humans; Immunoglobulin G; Immunoglobulin M; Madagascar; Malaria; Malaria, Falciparum; Malaria, Vivax; Plasmodium; Plasmodium falciparum; Plasmodium vivax; Prevalence; Spleen

The in vivo and in vitro response of Plasmodium falciparum to chloroquine was conducted in Ankazobe, a village located in the high plateau area. These studies confirmed the low level of chloroquine-resistance. The in vivo data indicate the absence of increase resistance during the 2 years study. Chloroquine is still the drug of choice for the treatment of malaria attack in this area.

Topics: Animals; Chloroquine; Drug Resistance; Humans; Madagascar; Malaria, Falciparum; Plasmodium falciparum

Anopheles mascarensis De Meillon, 1947, a mosquito that is native to Madagascar, is reported for the first time to act as a vector of Plasmodium falciparum malaria. From September 1989 to March 1990, 2, 499 An. mascarensis specimens from different regions of Madagascar were tested by an enzyme-linked immunosorbent assay (ELISA), using monoclonal antibodies against the circumsporozoite (CS) protein of the four human species of Plasmodium. The salivary glands of 237 specimens were also dissected. Fourteen of 1,864 specimens obtained from Sainte Marie island on the Malagasy east coast were found by ELISA to be positive for the CS protein of P. falciparum. In addition, two of 237 specimens that were dissected were observed to have sporozoites in the salivary glands. These sporozoites were identified as P. falciparum by ELISA. In the other regions studied, no positive specimens were found. Due to observed behavioral differences between east coast and highland populations of An. mascarensis, the possible presence of a species complex is discussed.

Topics: Animals; Anopheles; Enzyme-Linked Immunosorbent Assay; Humans; Insect Vectors; Madagascar; Malaria, Falciparum; Plasmodium falciparum

The recent reappearance of Plasmodium falciparum in the central highland plateaux of Madagascar has led to an important increase in both morbidity and mortality in the population. To understand the phenomena that originated this outbreak, and to evaluate the clinical and biological reactions of the population, we conducted entomological surveys during the whole malaria transmission season of 1988. In parallel, 41 individuals presenting with a malaria attack in January were given a curative antimalarial treatment and were followed weekly for 20 weeks, until the end of the transmission season, in June. During the follow-up, individuals presenting with a clinical malaria attack or with a parasite density above 5000 per mm3 of blood were again given antimalarial treatment. Overall, individuals presented with an average of 5.6 thick blood smears positive for P. falciparum, and 1.4 malaria attacks requiring treatment. Plasmodium falciparum prevalence rates gradually increased to 53.8% in April, one to two months after the observed peak of transmission, then decreased to 15.4% at the end of follow-up. The proportion of P. falciparum infections with clinical symptoms did not follow a similar temporal evolution and was significantly lower than at enrollment. Splenic rates gradually decreased from 29.3-2.6%, while anti-P. falciparum and anti-Pfl55/RESA antibodies increased. For the whole transmission season individuals experienced a mean 1.5 infective bites; the malaria vectors were Anopheles gambiae s. 1 and An. funestus. This study demonstrates that, in this population newly exposed to P. falciparum infections, almost all sporozoite inoculations lead to blood parasite infection requiring treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adult; Animals; Anopheles; Antibodies, Protozoan; Cohort Studies; Disease Outbreaks; Female; Humans; Madagascar; Malaria, Falciparum; Male; Plasmodium falciparum; Seasons

Data are reported from a malaria survey carried out in June 1991 in the small village of Ankadimbazinba, near Miantso, about 45 km North-West of Antananarivo (Madagascar). The objective was to evaluate the level of transmission of P. falciparum by entomological, parasitological and serological indices. All indices were found consistent with the description of a focus of hyperendemic transmission dependent on the presence of An. funestus at high density, corresponding to more than 50 females per house collected by hand catch. The positivity rate for the circumsporozoite protein (CS) of P. falciparum in blood-fed or gravid An. funestus was 2.0% (11/562) in the house resting sample. The parasite rate in the village population was 47.9% reaching 68.4% in the 0-14 age group and the gametocyte rate in the total sample was 25.0%. The seroprevalence of P. falciparum antisporozoite antibodies was 40.0% in children under 15 years old, 84.2% in the 15-29 age group and 90.9% in the over 29 age group.

Topics: Adult; Animals; Anopheles; Cattle; Child; Child, Preschool; Disease Reservoirs; Female; Housing; Housing, Animal; Humans; Infant; Insect Vectors; Madagascar; Malaria, Falciparum; Middle Aged; Plasmodium falciparum; Prevalence; Seroepidemiologic Studies; Swine

Proliferative responses of peripheral blood lymphocytes to synthetic peptides representing major epitopes of two malaria antigens (the merozoite ring-infected erythrocyte surface antigen and the sporozoite circumsporozoite protein) were investigated in Madagascar during a clinical Plasmodium falciparum episode. Thirty-seven patients greater than 10 years of age were enrolled at the beginning of the malaria transmission season and followed for four weeks. At enrollment, when the subjects presented with an acute infection, lymphocytes recovered from approximately 30% of them proliferated after peptide stimulation. These proliferative responses decreased sharply one and two weeks after treatment, with less than 10% responding to each peptide. Four weeks after treatment, the responses were only partially restored. The amplitude of these variations was not related to the initial parasitemia. At the individual level, proliferative response to each peptide varied greatly during the followup period, and this variation was unrelated to the presence of parasites in the blood.

Topics: Adolescent; Adult; Animals; Antigens, Protozoan; Antigens, Surface; Child; Female; Humans; Longitudinal Studies; Lymphocyte Activation; Madagascar; Malaria, Falciparum; Male; Middle Aged; Plasmodium falciparum; Protozoan Proteins; T-Lymphocytes