Population genetics analysis during the elimination process of Plasmodium falciparum in Djibouti
To investigate the importance of malaria as a public health problem in Djibouti, we studied 144 febrile subjects living south of Djibouti-city in the agricultural area of Ambouli. All blood slides examined were negative for parasites. Antibodies against the merozoite stage of Plasmodium falciparum were investigated by an indirect immunofluorescence assay using serial serum dilutions. Only 9 sera reacted negatively at the titer of 50 (the chosen cut-off for positivity). Fourteen sera tested positive at a titer above 1000. Percentages of seropositive subjects and geometric mean titers increased with age. We conclude that inhabitants of Ambouli were heavily exposed to Plasmodium falciparum in the recent past. However, our data do not allow to ascertain if the malaria infections were contracted inside or outside of the national territory, since Djiboutians are frequent and extensive travelers.