Asymptomatic Plasmodium vivax infections among Duffy-negative population in Kedougou, Senegal

In the southeastern Senegal, the report of Plasmodium vivax infections among febrile patients in Kedougou constitutes a new emerging health problem. Samples from 48 asymptomatic schoolchildren sampled twice a year over 2 years were used to explore the reservoir of P. vivax parasite infections in this region. Both Duffy genotyping and Plasmodium species diagnostic assays were performed. PCR assays detected Plasmodium genomic DNA in 38.5% (74/192) of samples. Pure P. falciparum and P. vivax infections were identified in 79.7% (59/74) and 20.3% (15/74) of samples, respectively. All schoolchildren were classified as Duffy-negative by genotyping. P. vivax infections were detected in five children: in two children during both years, in one child in 2010 and on May 2011, and only in 2010 for the remaining two children. This unexpectedly high proportion of P. vivax infections in asymptomatic Duffy-negative children highlights to consider vivax malaria as an emerging problem in Senegal.