Plasmodium Vivax Burden, Range and Transmission Among Duffy Negative Inhabitants in Cameroon.

Although Plasmodium vivax (P. vivax), one of the five malaria species causing parasites, has the widest geographical distribution, it is rare in sub-Saharan Africa due to the absence of a red blood cell receptor (Duffy antigen) in black Africans. Duffy-negative individuals are, for the most part, therefore refractory to P. vivax infection and the Duffy-negative phenotype is found at highest frequencies in Africa, whereas it is relatively rare elsewhere. P. vivax has however, been observed as single infections in up to 5% of Duffy-negative febrile patients in one health facility in Dschang, a region of low malaria transmission in Western highlands of Cameroon. Whereas in the littoral South West and Southern forest of Cameroon characterised by high malaria transmission, areas, there are contrasting molecular evidence of human P. vivax infection. While important, the significance is limited from an epidemiological point of view, concerning the source, transmission, distribution range of P. vivax. There is thus a challenge in the true estimation of malaria burden, as well as the attributable parasite species in infections occurring in the low transmission areas of Western Cameroon. As a consequence, our understanding of the local epidemiology of malaria in Western Cameroon warrants formal investigation. The current proposal is a multi-centre observational study. Its purpose is to characterise the malaria species composition and particularly exposure and burden of P. vivax across malaria endemic settings in Cameroon. It will use multiplex serological methods based on quantitative suspension array on finger-stick blood samples collected from febrile patients of ages 1-100 during two malaria transmission seasons in different eco-climatic regions in Cameroon.