The hide and seek of Plasmodium vivax in West Africa: report from a large-scale study in Beninese asymptomatic subjects

• Published in: Malaria journal Vol. 15; no. 1; p. 570
• Main Authors: Poirier, Philippe, Doderer-Lang, Cécile, Atchade, Pascal S., Lemoine, Jean-Philippe, de l’Isle, Marie-Louise Coquelin, Abou-bacar, Ahmed, Pfaff, Alexander W., Brunet, Julie, Arnoux, Lydia, Haar, Elodie, Filisetti, Denis, Perrotey, Sylvie, Chabi, Nicodeme W., Akpovi, Casimir D., Anani, Ludovic, Bigot, André, Sanni, Ambaliou, Candolfi, Ermanno
• Format: Journal Article
• Language: English
• Published: London BioMed Central 25.11.2016; BioMed Central Ltd
• Subjects: Analysis; Antibodies; Antibodies, Protozoan - blood; Asymptomatic Infections - epidemiology; Bacteriology; Benin - epidemiology; Biomedical and Life Sciences; Biomedicine; Blood Donors; Dosage and administration; Entomology; Enzyme-Linked Immunosorbent Assay; Epidemiology; Female; Health aspects; Human health and pathology; Humans; Infectious Diseases; Life Sciences; Local population; Malaria; Malaria, Vivax - epidemiology; Malaria, Vivax - pathology; Male; Microbiology; Microbiology and Parasitology; Microscopy; Parasites; Parasitology; Plasmodium vivax; Polymerase Chain Reaction; Protistology; Public Health; Risk factors; Seroepidemiologic Studies; Tropical Medicine; Viral antibodies; Benin; West Africa; Western Africa; Benin; MSP1; Malaria; CSP1; Blood donors; ELISA; Plasmodium vivax
• ISSN: 1475-2875; 1475-2875
• DOI: 10.1186/s12936-016-1620-z

Background Plasmodium vivax is considered to be absent from western Africa, where the prevalence of Duffy-negative red blood cell phenotype proves to be high. Several studies have, however, detected P. vivax infection cases in this part of Africa, raising the question of what is the actual prevalence of P. vivax in local populations. Methods The presence of P. vivax was investigated in a large population of healthy blood donors in Benin using microscopy, serology and molecular detection. The seroprevalence was measured with species-specific ELISA using two recombinant P. vivax proteins, namely r Pv MSP1 and r Pv CSP1. Specific molecular diagnosis of P. vivax infection was carried out using nested-PCR. The performances and cut-off values of both r Pv CSP1 and r Pv MSP1 ELISA were first assessed using sera from P. vivax -infected patients and from non-exposed subjects. Results Among 1234 Beninese blood donors, no parasites were detected when using microscopy, whereas 28.7% (354/1234) of patients exhibited had antibodies against r Pv MSP1, 21.6% (266/1234) against r Pv CSP1, and 15.2% (187/1234) against both. Eighty-four samples were selected for nested-PCR analyses, of which 13 were positive for P. vivax nested-PCR and all Duffy negative. Conclusion The results of the present study highlight an unexpectedly high exposure of Beninese subjects to P. vivax , resulting in sub-microscopic infections. This suggests a probably underestimated and insidious parasite presence in western Africa. While the vaccination campaigns and therapeutic efforts are all focused on Plasmodium falciparum , it is also essential to consider the epidemiological impact of P. vivax .