Plasmodium vivax Infections Detected in a Large Number of Febrile Duffy-Negative Africans in Dschang, Cameroon

The Duffy blood group is a critical receptor for Plasmodium vivax (Pv) invasion of red blood cells, and consequently, Pv infections were considered rare in sub-Saharan Africa where the prevalence of Duffy-negativity is high. However, recently, Pv infections have been found in Duffy-negative Africans throughout the malaria transmission area of sub-Saharan Africa, raising important questions concerning the molecular composition of these Pv clones and the red blood cell receptors that facilitate their invasion. Here, we describe an unusually high number of Pv infections in febrile Duffy-negative Africans in Dschang, Cameroon (177 of 500 outpatients), as compared with Santchou (two of 400 outpatients) and Kye'-Ossi (two of 101 outpatients), other areas in Cameroon. In the discussion, we speculate on the possible reasons why Dschang might account for the unusually large numbers of Pv infections in Duffy-negative individuals living there.