Asymptomatic Plasmodium falciparum and vivax infection in the neighborhood of Blondin, Saint-Georges-de-l'Oyapock District, French Guiana.

Optimized elimination strategies are needed to control transmission of malaria. As part of an elimination campaign, active detection of asymptomatic Plasmodium carriers by highly sensitive methods is deemed necessary. Asymptomatic carriage leads to complex scientific, ethical, and operational issues regarding individual or collective detection and treatment. To address this issue, a crosssectional study was carried out in French Guiana to determine the prevalence of asymptomatic Plasmodium carriage during an inter-epidemic season in the whole population of a neighborhood of Saint-Georges-de-l'Oyapock, along the Brazilian border. Fifty-eight participants out of 63 residents were screened. The median age was 23.3 years (range: 2 months-72 years), with a male/female sex-ratio of 0.56. The majority of the participants (74%, N = 43/58) reported a history of malaria, 12% (N = 7/58) during the past 12 months. All rapid diagnostic tests for malaria were negative. Among the 58 participants, malaria prevalence detected by nested-PCR (Polymerase Chain Reaction) was 3.6% (N = 2/56). Two asymptomatic carriers of Plasmodium were identified: one child with Plasmodium vivax and one adult with Plasmodium falciparum. These two carriers were treated and did not develop malaria within the eight months following the diagnosis. This study confirmed the presence of asymptomatic parasitaemias outside hyperendemic areas. However, the benefits of such an active detection and patient treatment to eliminate malaria in French Guiana need to be evaluated at a larger scale.