Frequency and distribution of mixed Plasmodium falciparum-vivax infections in French Guiana between 2000 and 2008.

Marine Ginouves,Aurélia Stefani,Vincent Veron,Magalie Demar,Eric Legrand,Félix Djossou,Ghislaine Prevot,Bernard Carme,Paul Brousse,Lise Musset,Mathieu Nacher

doi:10.1186/s12936-015-0971-1

Abstract

BackgroundThe two main plasmodial species in French Guiana are Plasmodium vivax and Plasmodium falciparum whose respective prevalence influences the frequency of mixed plasmodial infections. The accuracy of their diagnosis is influenced by the sensitivity of the method used, whereas neither microscopy nor rapid diagnostic tests allow a satisfactory evaluation of mixed plasmodial infections.MethodsIn the present study, the frequency of mixed infections in different part of French Guiana was determined using real time PCR, a sensitive and specific technique.ResultsFrom 400 cases of malaria initially diagnosed by microscopy, real time PCR showed that 10.75 % of the cases were mixed infections. Their prevalence varied considerably between geographical areas. The presence, in equivalent proportions, of the two plasmodial species in eastern French Guiana was associated with a much higher prevalence of mixed plasmodial infections than in western French Guiana, where the majority of the population was Duffy negative and thus resistant to vivax malaria.ConclusionClinicians must be more vigilant regarding mixed infections in co-endemic P. falciparum/P. vivax areas, in order to deliver optimal care for patients suffering from malaria. This may involve the use of rapid diagnostic tests capable of detecting mixed infections or low density single infections. This is important as French Guiana moves towards malaria elimination.

Highlights

The two main plasmodial species in French Guiana are Plasmodium vivax and Plasmodium falciparum whose respective prevalence influences the frequency of mixed plasmodial infections
Overall, mixed plasmodial infections were frequent in French Guiana with 10.75 % of malaria cases having mixed P. vivax/P. falciparum malaria
The incidence of P. vivax malaria is very low among Maroon populations, who are Duffy negative and the main ethnic group living on the Maroni River

Summary

Introduction

The two main plasmodial species in French Guiana are Plasmodium vivax and Plasmodium falciparum whose respective prevalence influences the frequency of mixed plasmodial infections. The accuracy of their diagnosis is influenced by the sensitivity of the method used, whereas neither microscopy nor rapid diagnostic tests allow a satisfactory evaluation of mixed plasmodial infections. The presence of P. falciparum was more frequent in western French Guiana, where the Maroon populations live. This population is resistant to P. vivax because, as most Africans, they do not express the Duffy antigen. The proportion of P. falciparum in French Guiana has decreased from 46 % of all malaria cases in 2005 to 30 % in 2014 [2, 9]

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Discussion

Conclusion