Effects of an intervention program to improve mental health and epilepsy care in Madagascar

BACKGROUND

Despite the high prevalence of mental disorders and epilepsy in low- and middle-income countries, nearly 80% of patients are not treated. In Madagascar, initiatives to improve access to epilepsy and mental health care, including public awareness and training of general practitioners (GPs), were carried out between 2013 and 2018. Our study's main objective was to assess the effectiveness of these initiatives, two to five years post-intervention.

METHODS

This quasi-experimental study (intervention vs. control areas) included five surveys assessing: general population's Knowledge Attitudes and Practices (KAP), GPs' KAP , number of epilepsy and mental health consultations at different levels of the healthcare system, diagnostic accuracy, and treatments' availability.

OUTCOMES

In the general population, KAP scores were higher in intervention areas for epilepsy (11.4/20 vs. 10.3/20; p = 0.003). For mental disorders, regardless of the area, KAP scores were low, especially for schizophrenia (1.1/20 and 0.1/20). Among GPs, KAP scores were higher in intervention areas for schizophrenia (6.0/10 vs. 4.5/10; p = 0.008) and epilepsy (6.9/10 vs. 6.2/10; p = 0.044). Overall, there was a greater proportion of mental health and epilepsy consultations in intervention areas (4.5% vs 2.3%). Although low, concordance between GPs' and psychiatrists' diagnoses was higher in intervention areas. There was a greater variety of anti-epileptic and psychotropic medications available in intervention areas.

INTERPRETATION

This research has helped to better understand the effectiveness of initiatives implemented in Madagascar to improve epilepsy and mental health care and to identify barriers which will need to be addressed.

FUNDING

Sanofi Global Health, as part of the Fight Against STigma Program.

Unveiling P. vivax invasion pathways in Duffy-negative individuals

Vivax malaria has long been thought to be absent from sub-Saharan Africa owing to the high proportion of individuals lacking the Duffy antigen receptor for chemokines (DARC) in their erythrocytes. The interaction between P. vivax Duffy-binding protein (PvDBP) and DARC is assumed to be the main pathway used by merozoites to invade reticulocytes. However, the increasing number of reports of vivax malaria cases in genotypically Duffy-negative (DN) individuals has raised questions regarding the P. vivax invasion pathway(s). Here, we show that a subset of DN erythroblasts transiently express DARC during terminal erythroid differentiation and that P. vivax merozoites, irrespective of their origin, can invade DARC+ DN erythroblasts. These findings reveal that a large number of DN individuals may represent a silent reservoir of deep P. vivax infections at the sites of active erythropoiesis with low or no parasitemia, and it may represent an underestimated biological problem with potential clinical consequences in sub-Saharan Africa.

Prevalence of molecular markers of resistance to sulfadoxine-pyrimethamine before and after community delivery of intermittent preventive treatment of malaria in pregnancy in sub-Saharan Africa: a multi-country evaluation

BACKGROUND

The effectiveness of community delivery of intermittent preventive treatment (C-IPT) of malaria in pregnancy (IPTp) with sulfadoxine-pyrimethamine has been evaluated in selected areas of the Democratic Republic of the Congo, Madagascar, Mozambique, and Nigeria. We aimed to assess the effect of C-IPTp on the potential development of Plasmodium falciparum resistance to sulfadoxine-pyrimethamine, since it could threaten the effectiveness of this strategy.

METHODS

Health facility-based cross-sectional surveys were conducted at baseline and 3 years after C-IPTp implementation in two neighbouring areas per country, one with C-IPTp intervention, and one without, in the four project countries. Dried blood spots from children under five years of age with clinical malaria were collected. Sulfadoxine-pyrimethamine resistance-associated mutations of the P falciparum dhfr (Asn51Ile/Cys59Arg/Ser108Asn/Ile164Leu) and dhps (Ile431Val/Ser436Ala/Ala437Gly/Lys540Glu/Ala581Gly/Ala613Ser) genes were analysed.

FINDINGS

2536 children were recruited between June 19 and Oct 10, 2018, during baseline surveys. Endline surveys were conducted among 2447 children between July 26 and Nov 30, 2021. In the Democratic Republic of the Congo, the dhfr/dhps IRNI/ISGEAA inferred haplotype remained lower than 10%, from 2% (5 of 296) at baseline to 8% (24 of 292) at endline, and from 3% (9 of 300) at baseline to 6% (18 of 309) at endline surveys in intervention and non-intervention areas respectively with no significant difference in the change between the areas. In Mozambique, the prevalence of this haplotype remained stable at over 60% (194 [64%] of 302 at baseline to 194 [64%] of 303 at endline, and 187 [61%] of 306 at baseline to 183 [61%] of 301 in endline surveys, in non-intervention and intervention areas respectively). No isolates harbouring the dhps ISGEAA genotype were found in Nigeria. In Madagascar, only five isolates with this haplotype were found in the non-intervention area (2 [>1%] of 300 at baseline and 3 [1%] of 300 at endline surveys). No isolates were found carrying the dhps ISGEGA genotype.

INTERPRETATION

C-IPTp did not increase the prevalence of molecular markers associated with sulfadoxine-pyrimethamine resistance after three years of programme implementation. These findings reinforce C-IPTp as a strategy to optimise the control of malaria during pregnancy, and support the WHO guidelines for prevention of malaria in pregnancy.

FUNDING

UNITAID [2017-13-TIPTOP].

Comparative effect of artemether-lumefantrine and artesunate-amodiaquine on gametocyte clearance in children with uncomplicated Plasmodium falciparum malaria in Madagascar

Background

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.

Methods

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.

Results

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.

Conclusion

This study demonstrates that AL has a more rapid effect on gametocyte clearance compared to ASAQ in children with uncomplicated Plasmodium falciparum malaria.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-022-04369-2.

DNA recovery from used malaria RDT to detect Plasmodium species and to assess Plasmodium falciparum genetic diversity: a pilot study in Madagascar

Background

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.

Methods

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.

Results

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.

Conclusion

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

Plasmodium falciparum pfhrp2 and pfhrp3 Gene Deletions from Persons with Symptomatic Malaria Infection in Ethiopia, Kenya, Madagascar, and Rwanda

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.

Effects of an educational comic book on epilepsy-related knowledge, attitudes and practices among schoolchildren in Madagascar

INTRODUCTION

Epilepsy is a chronic disease of the brain that affects approximately 50 million people globally, with over 80 % of them living in low- and middle-income countries (LMICs). In Madagascar, as in most LMICs, one of the main obstacles to treatment is the stigma and discrimination experienced by patients. Beliefs and prejudices regarding this disease are common, especially among children. "Ao Tsara" is an educational comic book regarding epilepsy, which has been translated in Malagasy from a French version, and which objective is to raise awareness and fight epilepsy related stigma and discrimination. Comic books have indeed been used successfully to raise awareness and change behaviors in several areas of public health.

METHODS

We conducted a study to evaluate the effect of a single reading of this comic book on epilepsy related knowledge, attitudes and practices (KAP) in schoolchildren in Madagascar. This quasi-experimental study compared data collected before and immediately after reading "Ao Tsara". It was conducted both in a school in an urban area and in a school in a rural area.

RESULTS

We recruited 244 children with a mean age of 11.4 (±1.5) in this study. We noted a significant improvement in the global KAP score after reading the comic book, overall as well as both in the urban school and the rural school. Out of a maximum score of twenty, the global KAP score increased from 9.4 to 11.2 (p < 0.001). Although the increase in knowledge was reasonable (from 10.2 to 12.9, p < 0.001) and the corresponding subscore after reading the comic book was at a satisfactory level, that was not the case for attitudes & practices, where the sub-score despite a significant increase remained low (from 8.7 to 9.5 out of a maximum score of twenty, p < 0.001). The comic book was much appreciated by the children with more than 50.0 % giving it the top rating, and 66.4 % stating they had learned a lot from it.

CONCLUSION

A single reading of the comic book has demonstrated a positive effect on the knowledge, attitudes and practices of primary school children in Madagascar. This educational tool, which was much enjoyed by the children, could be of great value to raise awareness about epilepsy in Madagascar. By targeting a slightly older age group and adjusting the reading approach, the outcomes could be optimized especially in terms of attitudes and practices.

School-Based Serosurveys to Assess the Validity of Using Routine Health Facility Data to Target Malaria Interventions in the Central Highlands of Madagascar

BACKGROUND

In low-malaria-transmission areas of Madagascar, annual parasite incidence (API) from routine data has been used to target indoor residual spraying at subdistrict commune level. To assess validity of this approach, we conducted school-based serological surveys and health facility (HF) data quality assessments in 7 districts to compare API to gold-standard commune-level serological measures.

METHODS

At 2 primary schools in each of 93 communes, 60 students were randomly selected with parents and teachers. Capillary blood was drawn for rapid diagnostic tests (RDTs) and serology. Multiplex bead-based immunoassays to detect antibodies to 5 Plasmodium falciparum antigens were conducted, and finite mixture models used to characterize seronegative and seropositive populations. Reversible catalytic models generated commune-level annual seroconversion rates (SCRs). HF register data were abstracted to assess completeness and accuracy.

RESULTS

RDT positivity from 12 770 samples was 0.5%. Seroprevalence to tested antigens ranged from 17.9% (MSP-1) to 59.7% (PF13). Median commune-level SCR was 0.0108 (range, 0.001-0.075). Compared to SCRs, API identified 71% (95% confidence interval, 51%-87%) of the 30% highest-transmission communes; sensitivity declined at lower levels. Routine data accuracy did not substantially affect API performance.

CONCLUSIONS

API performs reasonably well at identifying higher-transmission communes but sensitivity declined at lower transmission levels.

Risk Factors for Malaria Infection in Central Madagascar: Insights from a Cross-Sectional Population Survey

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 Plasmodium infection diagnosed by microscopy, RDT, and molecular diagnosis was 2.4%, 4.1%, and 13.8%, respectively. This diagnostic discordance was greatest for Plasmodium vivax infection, which was 98.5% submicroscopic. Village location, insecticide-treated bednet ownership, and fever were significantly associated with infection outcomes, as was presence of another infected individual in the household. Duffy-negative individuals were diagnosed with P. vivax, but with reduced odds relative to Duffy-positive hosts. The observation of high proportions of submicroscopic infections calls for a wider assessment of the parasite reservoir in other regions of the island, particularly given the country's current focus on malaria elimination and the poorly documented distribution of the non-P. falciparum parasite species.

[Adherence of private sector providers to uncomplicated malaria management policy in Madagascar]

INTRODUCTION

This study aims to assess the adherence of private health providers to the use of malaria rapid diagnostic tests (RDTs) and to the prescription of artemisinin-containing combinations (ACT) in patients with uncomplicated malaria.

METHODS

We conducted an analytical, retrospective and cross-sectional study in 11 Madagascar's health districts divided into four epidemiological strata in September and in October 2015. A total of 43 health providers from 39 private health care facilities (PHF) were interviewed and visited.

RESULTS

Health providers declared having read the malaria management manual in 16.3% of cases (4/43). Only one quarter (25.6%) of health providers had RDTs in their office. ACT was reported as "first-line drug" for the treatment of uncomplicated malaria by 83.7% of health providers. In practice, 55.6% of health providers had doubts about the results of the RDTs. The use of antimalarial drugs, despite having had negative RDTs results (38.2%), was more frequent among those who had raised doubts (p = 0.03). Conversely, despite having had positive RDTs results, half of the health providers did not prescribe ACT (50%). The decision to not participate in periodic reviews by the Health District (p = 0.05) negatively influenced the adherence to the policies.

CONCLUSION

The low adherence of private health providers to the national guidelines for the management of uncomplicated malaria raises questions about the importance of exercising more control over health providers activities.

Efficacy of artesunate-amodiaquine in the treatment of falciparum uncomplicated malaria in Madagascar

Background

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.

Methods

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.

Results

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.

Conclusion

The ASAQ combination remains highly effective for the treatment of uncomplicated falciparum malaria in Madagascar.

Spatio-temporal mapping of Madagascar's Malaria Indicator Survey results to assess Plasmodium falciparum endemicity trends between 2011 and 2016

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Prevalence and genetic variants of G6PD deficiency among two Malagasy populations living in Plasmodium vivax-endemic areas

BACKGROUND

The prevalence and variants of G6PD deficiency in the Plasmodium vivax-endemic zones of Madagascar remain unknown. The admixed African-Austronesian origins of the Malagasy population make it probable that a heterogeneous mix of genetic variants with a spectrum of clinical severity will be circulating. This would have implications for the widespread use of P. vivax radical cure therapy. Two study populations in the P. vivax-endemic western foothills region of Madagascar were selected for G6PD screening. Both the qualitative fluorescent spot test and G6PD genotyping were used to screen all participants.

RESULTS

A total of 365 unrelated male volunteers from the Tsiroanomandidy, Mandoto, and Miandrivazo districts of Madagascar were screened and 12.9% were found to be phenotypically G6PD deficient. Full gene sequencing of 95 samples identified 16 single nucleotide polymorphisms, which were integrated into a genotyping assay. Genotyping (n = 291) found one individual diagnosed with the severe G6PD Mediterranean ^C563T mutation, while the remaining G6PD deficient samples had mutations of African origin, G6PD A- and G6PD A.

CONCLUSIONS

Deployment of P. vivax radical cure in Madagascar must be considerate of the risks presented by the observed prevalence of G6PDd prevalence. The potential morbidity associated with cumulative episodes of P. vivax clinical relapses requires a strategy for increasing access to safe radical cure. The observed dominance of African G6PDd haplotypes is surprising given the known mixed African-Austronesian origins of the Malagasy population; more widespread surveying of G6PDd epidemiology across the island would be required to characterize the distribution of G6PD haplotypes across Madagascar.

Plasmodium vivax Diversity and Population Structure across Four Continents

Plasmodium vivax is the geographically most widespread human malaria parasite. To analyze patterns of microsatellite diversity and population structure across countries of different transmission intensity, genotyping data from 11 microsatellite markers was either generated or compiled from 841 isolates from four continents collected in 1999–2008. Diversity was highest in South-East Asia (mean allelic richness 10.0–12.8), intermediate in the South Pacific (8.1–9.9) Madagascar and Sudan (7.9–8.4), and lowest in South America and Central Asia (5.5–7.2). A reduced panel of only 3 markers was sufficient to identify approx. 90% of all haplotypes in South Pacific, African and SE-Asian populations, but only 60–80% in Latin American populations, suggesting that typing of 2–6 markers, depending on the level of endemicity, is sufficient for epidemiological studies. Clustering analysis showed distinct clusters in Peru and Brazil, but little sub-structuring was observed within Africa, SE-Asia or the South Pacific. Isolates from Uzbekistan were exceptional, as a near-clonal parasite population was observed that was clearly separated from all other populations (F_ST>0.2). Outside Central Asia F_ST values were highest (0.11–0.16) between South American and all other populations, and lowest (0.04–0.07) between populations from South-East Asia and the South Pacific. These comparisons between P. vivax populations from four continents indicated that not only transmission intensity, but also geographical isolation affect diversity and population structure. However, the high effective population size results in slow changes of these parameters. This persistency must be taken into account when assessing the impact of control programs on the genetic structure of parasite populations.

Plasmodium vivax is the predominant malaria parasite in Latin America, Asia and the South Pacific. Different factors are expected to shape diversity and population structure across continents, e.g. transmission intensity which is much lower in South America as compared to Southeast-Asia and the South Pacific, or geographical isolation of P. vivax populations in the South Pacific. We have compiled data from 841 isolates from South and Central America, Africa, Central Asia, Southeast-Asia and the South Pacific typed with a panel of 11 microsatellite markers. Diversity was highest in Southeast-Asia, where transmission is intermediate-high and migration of infected hosts is high, and lowest in South America and Central Asia where malaria transmission is low and focal. Reducing the panel of microsatellites showed that 2–6 markers are sufficient for genotyping for most drug trials and epidemiological studies, as these markers can identify >90% of all haplotypes. Parasites clustered according to continental origin, with high population differentiation between South American and Central Asian populations and the other populations, and lowest differences between Southeast-Asia and the South Pacific. Current attempts to reduce malaria transmission might change this pattern, but only after transmission is reduced for an extended period of time.

Whole genome sequencing of field isolates reveals a common duplication of the Duffy binding protein gene in Malagasy Plasmodium vivax strains

Background

Plasmodium vivax is the most prevalent human malaria parasite, causing serious public health problems in malaria-endemic countries. Until recently the Duffy-negative blood group phenotype was considered to confer resistance to vivax malaria for most African ethnicities. We and others have reported that P. vivax strains in African countries from Madagascar to Mauritania display capacity to cause clinical vivax malaria in Duffy-negative people. New insights must now explain Duffy-independent P. vivax invasion of human erythrocytes.

Methods/Principal Findings

Through recent whole genome sequencing we obtained ≥70× coverage of the P. vivax genome from five field-isolates, resulting in ≥93% of the Sal I reference sequenced at coverage greater than 20×. Combined with sequences from one additional Malagasy field isolate and from five monkey-adapted strains, we describe here identification of DNA sequence rearrangements in the P. vivax genome, including discovery of a duplication of the P. vivax Duffy binding protein (PvDBP) gene. A survey of Malagasy patients infected with P. vivax showed that the PvDBP duplication was present in numerous locations in Madagascar and found in over 50% of infected patients evaluated. Extended geographic surveys showed that the PvDBP duplication was detected frequently in vivax patients living in East Africa and in some residents of non-African P. vivax-endemic countries. Additionally, the PvDBP duplication was observed in travelers seeking treatment of vivax malaria upon returning home. PvDBP duplication prevalence was highest in west-central Madagascar sites where the highest frequencies of P. vivax-infected, Duffy-negative people were reported.

Conclusions/Significance

The highly conserved nature of the sequence involved in the PvDBP duplication suggests that it has occurred in a recent evolutionary time frame. These data suggest that PvDBP, a merozoite surface protein involved in red cell adhesion is rapidly evolving, possibly in response to constraints imposed by erythrocyte Duffy negativity in some human populations.

Malaria results from infection of human red blood cells (RBC) by Plasmodium parasite's merozoite. For Plasmodium vivax the process of RBC invasion has been hypothesized to depend on interactions between the parasite's Duffy binding protein (PvDBP) and human Duffy blood group antigen because Duffy-negative people (most often people of African descent) were shown to be highly resistant to RBC infection and disease. Over the past five years, researchers are reporting with increasing frequency that Duffy-negative individuals are infected with P. vivax. This raises new questions as to how P. vivax infects the RBC when the Duffy blood group antigen is not available. Here we show that the parasite's Duffy binding protein gene has been duplicated in multiple P. vivax strains, especially at high prevalence in Madagascar. The specificity and prevalence of this polymorphism suggest that the parasite genome has responded to the barrier of Duffy negativity through the duplication of the PvDBP gene. Our results indicate that the PvDBP duplication is a recent event and provide novel research avenues to understand alternative pathways for P. vivax RBC invasion.

Global analysis of Plasmodium falciparum Na(+)/H(+) exchanger (pfnhe-1) allele polymorphism and its usefulness as a marker of in vitro resistance to quinine

The aim of this study was to provide a comprehensive analysis of the worldwide genetic polymorphism of ms4760 alleles of the pfnhe-1 gene and to discuss their usefulness as molecular marker of quinine resistance (QNR). A new numbering of ms4760 allele, classification grouping ms4760 alleles according to the number of DNNND and DDNHNDNHNND repeat motifs in blocks II and V was also proposed. A total of 1508 ms4760 sequences from isolates, culture-adapted parasites or reference strains from various geographical regions were retrieved from GenBank (last update on 15th June 2012) or from publications and were used for genetic analyses. The association of different alleles of pfnhe-1 with resistance to quinoline antimalarial drugs showed marked geographic disparities. The validity and reliability of candidate polymorphisms in pfnhe-1 gene as molecular markers of QNR appeared restricted to endemic areas from South Asia or possibly East African countries and needs to be confirmed.

Whole genome sequencing of field isolates provides robust characterization of genetic diversity in Plasmodium vivax

Background

An estimated 2.85 billion people live at risk of Plasmodium vivax transmission. In endemic countries vivax malaria causes significant morbidity and its mortality is becoming more widely appreciated, drug-resistant strains are increasing in prevalence, and an increasing number of reports indicate that P. vivax is capable of breaking through the Duffy-negative barrier long considered to confer resistance to blood stage infection. Absence of robust in vitro propagation limits our understanding of fundamental aspects of the parasite's biology, including the determinants of its dormant hypnozoite phase, its virulence and drug susceptibility, and the molecular mechanisms underlying red blood cell invasion.

Methodology/Principal Findings

Here, we report results from whole genome sequencing of five P. vivax isolates obtained from Malagasy and Cambodian patients, and of the monkey-adapted Belem strain. We obtained an average 70–400 X coverage of each genome, resulting in more than 93% of the Sal I reference sequence covered by 20 reads or more. Our study identifies more than 80,000 SNPs distributed throughout the genome which will allow designing association studies and population surveys. Analysis of the genome-wide genetic diversity in P. vivax also reveals considerable allele sharing among isolates from different continents. This observation could be consistent with a high level of gene flow among parasite strains distributed throughout the world.

Conclusions

Our study shows that it is feasible to perform whole genome sequencing of P. vivax field isolates and rigorously characterize the genetic diversity of this parasite. The catalogue of polymorphisms generated here will enable large-scale genotyping studies and contribute to a better understanding of P. vivax traits such as drug resistance or erythrocyte invasion, partially circumventing the lack of laboratory culture that has hampered vivax research for years.

Plasmodium vivax is the most frequently transmitted and widely distributed cause of malaria in the world. Each year P. vivax is responsible for approximately 250 million clinical cases of malaria and its global economic burden, placed largely on the poor, has been estimated to exceed US$1.4 billion. In contrast to P. falciparum, P. vivax cannot be propagated in continuous in vitro culture and this limits our understanding of the parasite’s biology. In this study, we sequenced the entire genome of five P. vivax isolates directly from blood samples of infected patients. Our data indicated that each patient was infected with multiple P. vivax strains. We also identified more than 80,000 DNA polymorphisms distributed throughout the genome that will enable future studies of the P. vivax population and association mapping studies. Our study illustrates the potential of genomic studies for better understanding P. vivax biology and how the parasite successfully evades malaria elimination efforts worldwide.

Compliance, safety, and effectiveness of fixed-dose artesunate-amodiaquine for presumptive treatment of non-severe malaria in the context of home management of malaria in Madagascar

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.

Management of uncomplicated malaria in febrile under five-year-old children by community health workers in Madagascar: reliability of malaria rapid diagnostic tests

Background

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).

Methods

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.

Results

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.

Conclusion

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.

In vitro susceptibility to pyrimethamine of DHFR I164L single mutant Plasmodium falciparum

Background

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.

Methods

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.

Results

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 (IC₅₀) < 10 nM. The geometric mean of IC₅₀ 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 IC₅₀ of the triple mutant parasite (13,804 nM).

Conclusion

The IC₅₀s 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 IC₅₀s 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.

[Resistance of Plasmodium falciparum to antimalarial drugs: impact on malaria pre-elimination in Madagascar]

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.

Chloroquine clinical failures in P. falciparum malaria are associated with mutant Pfmdr-1, not Pfcrt in Madagascar

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.

Longitudinal survey of malaria morbidity over 10 years in Saharevo (Madagascar): further lessons for strengthening malaria control

Background

Madagascar has been known for having bio-geo-ecological diversity which is reflected by a complex malaria epidemiology ranging from hyperendemic to malaria-free areas. Malaria-related attacks and infection are frequently recorded both in children and adults living in areas of low malaria transmission. To integrate this variability in the national malaria control policy, extensive epidemiological studies are required to up-date previous records and adjust strategies.

Methods

A longitudinal malaria survey was conducted from July 1996 to June 2005 among an average cohort of 214 villagers in Saharevo, located at 900 m above the sea. Saharevo is a typical eastern foothill site at the junction between a costal wet tropical area (equatorial malaria pattern) and a drier high-altitude area (low malaria transmission).

Results

Passive and active malaria detection revealed that malaria transmission in Saharevo follows an abrupt seasonal variation. Interestingly, malaria was confirmed in 45% (1,271/2,794) of malaria-presumed fevers seen at the health centre. All four Plasmodia that infect humans were also found: Plasmodium falciparum; Plasmodium vivax, Plasmodium malariae and Plasmodium ovale. Half of the malaria-presumed fevers could be confirmed over the season with the highest malaria transmission level, although less than a quarter in lower transmission time, highlighting the importance of diagnosis prior to treatment intake. P. falciparum malaria has been predominant (98%). The high prevalence of P. falciparum malaria affects more particularly under 10 years old children in both symptomatic and asymptomatic contexts. Children between two and four years of age experienced an average of 2.6 malaria attacks with P. falciparum per annum. Moreover, estimated incidence of P. falciparum malaria tends to show that half of the attacks (15 attacks) risk to occur during the first 10 years of life for a 60-year-old adult who would have experienced 32 malaria attacks.

Conclusion

The incidence of malaria decreased slightly with age but remained important among children and adults in Saharevo. These results support that a premunition against malaria is slowly acquired until adolescence. However, this claims for a weak premunition among villagers in Saharevo and by extension in the whole eastern foothill area of Madagascar. While the Malagasy government turns towards malaria elimination plans nowadays, choices and expectations to up-date and adapt malaria control strategies in the foothill areas are discussed in this paper.

Epidemiological situation of malaria in Madagascar: baseline data for monitoring the impact of malaria control programmes using serological markers

The aim of this study was to provide baseline information of the epidemiological situation of malaria in Madagascar using serological markers. We carried out cross-sectional studies in schoolchildren from eight sites in the four different malarious epidemiological strata of Madagascar. We studied the prevalence of anti-MSP1 antibodies to assess the burden, and anti-CSP antibodies to estimate the transmission intensity, of malaria. The overall prevalence of each antibody tested was 46.1% for anti-PfMSP-1, 15.2% for anti-PvMSP-1, 14.9% for anti-PfCSP, 4.9% for anti-PvCSP and 2.4% for anti-PmCSP. The prevalence of the five antibodies varied significantly between the sites (P<10(-6)). We also found significant effects of ethnic origin on the prevalence of anti-PfMSP1 antibodies. With regular testing in the same target populations, this data will be particularly useful for managing the elimination strategy supported by the Malagasy Government.

Randomized, multicentre assessment of the efficacy and safety of ASAQ--a fixed-dose artesunate-amodiaquine combination therapy in the treatment of uncomplicated Plasmodium falciparum malaria

Background

The use of artemisinin derivative-based combination therapy (ACT) such as artesunate plus amodiaquine is currently recommended for the treatment of uncomplicated Plasmodium falciparum malaria. Fixed-dose combinations are more adapted to patients than regimens involving multiple tablets and improve treatment compliance. A fixed-dose combination of artesunate + amodiaquine (ASAQ) was recently developed. To assess the efficacy and safety of this new combination and to define its optimum dosage regimen (once or twice daily) in the treatment of uncomplicated P. falciparum malaria, a multicentre clinical study was conducted.

Methods

A multicentre, randomized, controlled, investigator-blinded, parallel-group study was conducted in five African centers in Cameroon, Madagascar, Mali and Senegal from March to December 2006. Efficacy and safety of ASAQ were assessed compared to those of artemether + lumefantrine (AL). The WHO protocol with a 28-day follow-up for assessing the drug therapeutic efficacy was used. Patients suffering from uncomplicated P. falciparum malaria were randomized to receive ASAQ orally once daily (ASAQ1), ASAQ twice daily (ASAQ2) or AL twice daily (AL) for three days. The primary outcome was PCR-corrected parasitological cure rate and clinical response.

Results

Of 941 patients initially randomized and stratified into two age groups (<5 years, and ≥5 years), 936 (99.5%) were retained for the intent to treat (ITT) analysis, and 859 (91.3%) patients for the per protocol (PP) analysis. Among ITT population, up to D28, PCR-corrected adequate parasitological and clinical response rates were 95.2% in the ASAQ1 group, 94.9% in the ASAQ2 group and 95.5% in the AL group. Moreover, the cure rate evaluated among PP population was ≥98.5% in both ASAQ therapeutic arms. Therapeutic response rates did not display any significant differences between age groups or between one geographical site and another. Altogether, this demonstrates the non-inferiority of ASAQ1 regimen compared to both ASAQ2 and AL regimens. During follow-up mild and moderate adverse events including gastrointestinal and/or nervous disorders were reported in 29.3% of patients, with no difference between groups in the nature, frequency or intensity of adverse events.

Conclusion

The non-inferiority of ASAQ compared with AL was demonstrated. The fixed-dose combination artesunate + amodiaquine (ASAQ) is safe and efficacious even in young children under 5 years of age. Whilst administration on a twice-a-day basis does not improve the efficacy of ASAQ significantly, a once-a-day intake of this new combination clearly appears as an effective and safe therapy in the treatment of uncomplicated P. falciparum malaria both in adults and children. Implications of such findings are of primary importance in terms of public health especially in African countries. As most national policies plan to strengthen malaria control to reach the elimination of this disease, anti-malarial drugs such as the artesunate + amodiaquine fixed-dose ACT will play a pivotal role in this process.

Trial registration

The protocol was registered with the www.clinicaltrials.gov open clinical trial registry under the identifier number NCT00316329.

Rapid detection of point mutations in Plasmodium falciparum genes associated with antimalarial drugs resistance by using High-Resolution Melting analysis

We have developed a High-Resolution DNA Melting method to detect mutations related to Plasmodium falciparum resistance. This method is based on real-time PCR followed by High Resolution Melting ramping from 67 degrees C to 80 degrees C with fluorescence data acquisition set at 0.1 degrees C increments. The accuracy of the technique was assessed using 177 P. falciparum clinical isolates and two reference strains. Results perfectly matched those obtained by DNA sequencing for some important genetic markers of P. falciparum resistance. This technique could be of great value for epidemiological studies, especially in developing countries.

Evaluation of two new immunochromatographic assays for diagnosis of malaria

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.

Assessment of the efficacy of antimalarial drugs recommended by the National Malaria Control Programme in Madagascar: up-dated baseline data from randomized and multi-site clinical trials

Background

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).

Methods

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.

Results

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.

Conclusion

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.

Plasmodium vivax dhfr and dhps mutations in isolates from Madagascar and therapeutic response to sulphadoxine-pyrimethamine

Background

Four of five Plasmodium species infecting humans are present in Madagascar. Plasmodium vivax remains the second most prevalent species, but is understudied. No data is available on its susceptibility to sulphadoxine-pyrimethamine, the drug recommended for intermittent preventive treatment during pregnancy. In this study, the prevalence of P. vivax infection and the polymorphisms in the pvdhfr and pvdhps genes were investigated. The correlation between these polymorphisms and clinical and parasitological responses was also investigated in P. vivax-infected patients.

Methods

Plasmodium vivax clinical isolates were collected in eight sentinel sites from the four major epidemiological areas for malaria across Madagascar in 2006/2007. Pvdhfr and pvdhps genes were sequenced for polymorphism analysis. The therapeutic efficacy of SP in P. vivax infections was assessed in Tsiroanomandidy, in the foothill of the central highlands. An intention-to-treat analysis of treatment outcome was carried out.

Results

A total of 159 P. vivax samples were sequenced in the pvdhfr/pvdhps genes. Mutant-types in pvdhfr gene were found in 71% of samples, and in pvdhps gene in 16% of samples. Six non-synonymous mutations were identified in pvdhfr, including two novel mutations at codons 21 and 130. For pvdhps, beside the known mutation at codon 383, a new one was found at codon 422. For the two genes, different combinations were ranged from wild-type to quadruple mutant-type. Among the 16 patients enrolled in the sulphadoxine-pyrimethamine clinical trial (28 days of follow-up) and after adjustment by genotyping, 3 (19%, 95% CI: 5%–43%) of them were classified as treatment failure and were pvdhfr 58R/117N double mutant carriers with or without the pvdhps 383G mutation.

Conclusion

This study highlights (i) that genotyping in the pvdhfr and pvdhps genes remains a useful tool to monitor the emergence and the spread of P. vivax sulphadoxine-pyrimethamine resistant in order to improve the national antimalarial drug policy, (ii) the issue of using sulphadoxine-pyrimethamine as a monotherapy for intermittent preventive treatment of pregnant women or children.

Accuracy and reliability of malaria diagnostic techniques for guiding febrile outpatient treatment in malaria-endemic countries

The main purpose of this study was to assess the accuracy of various techniques available for diagnosis of malaria. Blood samples were collected from 313 patients with clinical suspicion of uncomplicated malaria in 2 primary health centers in Madagascar. The presence of Plasmodium parasites was assessed by conventional microscopy, 2 rapid diagnostic tests (one HRP2-based test, PALUTOP(+4), and one pLDH-based test, OptiMAL-IT), and real-time polymerase chain reaction (PCR), which is used as the "gold standard" method. The degree of agreement observed was very high for microscopy (0.99) and the HRP2-based test (0.93) and high for the pLDH-based test (0.82). Public-health implications are also discussed in this paper.

Short report: prevalence and chloroquine sensitivity of Plasmodium malariae in Madagascar

We report the results of clinical studies carried out at six sites in Madagascar, between January and October 2006. The aims were (i) to update our knowledge of the burden of Plasmodium malariae infection and (ii) to assess the therapeutic efficacy of chloroquine for uncomplicated quartan malaria. Our findings confirm that P. malariae is the third leading cause of malaria, accounting for 1.1% of all malarial infections. They also demonstrate that chloroquine-currently recommended for the home management of presumed malaria in children under the age of five years and commonly used by adults-remains highly effective in patients with uncomplicated P. malariae infection.

Randomized clinical trial of artemisinin versus non-artemisinin combination therapy for uncomplicated falciparum malaria in Madagascar

Background

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).

Methods

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.

Results

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.

Conclusion

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.

Which malaria rapid test for Madagascar? Field and laboratory evaluation of three tests and expert microscopy of samples from suspected malaria patients in Madagascar

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 parasitemia<or=500 parasites/microL for P. falciparum and<or=5,000 parasites/microL for other Plasmodium spp. On the basis of World Health Organization recommendations, only the CareStart Malaria test and the OptiMAL-IT test had sensitivities greater than 95% for samples with parasitemias>or=100 parasites/microL.

Use of pre-packaged chloroquine for the home management of presumed malaria in Malagasy children

Objective

The main objective of this study was to assess the quality of home malaria management with pre-packaged chloroquine in two areas in the Moramanga district of Madagascar. The knowledge, attitude and practices of care providers in terms of home treatment options were evaluated and compared. The availability of treatment options by studying retailers and community-based service providers was also investigated.

Methods

A cross-sectional investigation in two communities, in the hamlets and villages located close to carers, retailers, community-based service providers and primary health centres was carried out.

Results

Carers in the two districts were equally well aware of the use of pre-packaged chloroquine. Their first response to the onset of fever was to treat children with this antimalarial drug at home. The dose administered and treatment compliance were entirely satisfactory (100%) with pre-packaged chloroquine and rarely satisfactory (1.6% to 4.5%) with non pre-packaged chloroquine. In cases of treatment failure, the carers took patients to health centres. Chloroquine was supplied principally by private pharmacies and travelling salesmen selling unpackaged chloroquine tablets. Non pre-packaged chloroquine was the most common drug used at health centres. The frequency of positive rapid malaria tests (P = 0.01) was significantly higher in children treated with non pre-packaged chloroquine (38%) than in children treated with pre-packaged chloroquine (1.3%).

Conclusion

Home malaria management should be improved in Madagascar. Efforts should focus on communication, the training of community-based service providers, access to pre-packaged drugs and the gradual withdrawal of pre-packaged chloroquine and its replacement by pre-packaged artemisinin-based combination therapies.

Monitoring susceptibility to sulfadoxine-pyrimethamine among cases of uncomplicated, Plasmodium falciparum malaria in Saharevo, Madagascar

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.

Susceptibility of Plasmodium falciparum to the drugs used to treat severe malaria (quinine) and to prevent malaria (mefloquine, cycloguanil) in Comoros Union and Madagascar

OBJECTIVES

To monitor the sensitivity of Plasmodium falciparum to the drugs used to treat severe malaria and to prevent malaria in Comoros and Madagascar.

DESIGN

We used the in vitro isotopic method to test the sensitivity of P. falciparum to quinine, mefloquine and cycloguanil.

RESULTS

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.

CONCLUSION

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.

[National Network study to perpetuate the surveillance of Plasmodium falciparum sensitivity to antimalarials in Madagascar]

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.

[Assessment of sulfadoxine-pyriméthamine (Fansidar, Paludar) efficacy in patients with uncomplicated malaria in Madagascar: preliminary study to propose a simplified study protocol]

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.

In-vitro sensitivity of Plasmodium falciparum to chloroquine, halofantrine, mefloquine and quinine in Madagascar

OBJECTIVE

To determine how sensitive Plasmodium falciparum is to the major antimalarial drugs in Madagascar.

DESIGN

Assessment of Plasmodium falciparum isolates sensitivity to antimalarials, by use of the in-vitro radioisotope method.

SETTING

Ankazobe and Saharevo in the foothill areas; and Toamasina and Tolagnaro in the coastal areas (between January 1998 and November 1999).

SUBJECTS

Primary Plasmodium falciparum isolates from patients with uncomplicated malaria attack.

RESULTS

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.

CONCLUSION

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.

Madagascan isolates of Plasmodium falciparum showing low sensitivity to artemether in vitro

In Madagascar, although chloroquine (CQ) remains the first-line treatment of choice for malaria, the gradual spread of resistance to this antimalarial drug is of increasing concern. As part of a larger investigation of the effectiveness of the second- and third-line drugs used to treat malaria, the in-vitro susceptibilities of Plasmodium falciparum collected in Madagascar to CQ, mefloquine (MQ) and artemether (ART) were therefore investigated. Median inhibitory concentrations (IC(50)) were determined for isolates collected from residents of two villages in the foothills of the central highlands. The IC(50) for ART ranged from 0.23-17.50 nM [N = 51; geometric mean = 4.02 nM; 95% confidence interval (CI) = 2.99-5.05 nM], four isolates exhibiting IC(50) (> 12 nM) indicative of resistance to this drug. The artemether IC(50) were found to be correlated with those of CQ (N = 46; Spearman's r = 0.51; P = 0.0002), which varied widely (0.4-254.3 nM; mean = 23.4 nM; CI = 7.1-39.7 nM; N = 46). Five (11%) of the 46 isolates exposed to CQ in vitro were considered resistant to this drug (i.e. to have IC(50) > 100 nM), with IC(50) ranging from 109-245.3 nM (mean = 171.6 nM; CI = 110.4-232.8 nM). However, all the CQ-resistant isolates were considered sensitive to ART and vice versa. All the isolates tested also appeared sensitive to MQ (IC(50) = 2.21-43.1 nM; mean = 10.5 nM; CI = 7.95-13.07 nM; N = 46), the IC(50) for MQ being correlated with those for CQ (N = 46; Spearman's r =0.46; P = 0.001). There was no significant correlation between ART and MQ activities. Although the sample was fairly small, the present results indicate that P. falciparum in Madagascar is generally becoming less sensitive to CQ and ART. The observation of a correlation between the IC(50) for these two drugs perhaps indicates that artemisinin derivatives would be better used in combination with antimalarial drugs other than 4-aminoquinolines.