Near-fixation of a Pfmsp1 block 2 allelic variant in genetically diverse Plasmodium falciparum populations across Western Colombia

Assessment of the genetic diversity of Plasmodium falciparum in 110 Colombian isolates revealed that nearly all the parasites in the 97 isolates collected in endemic regions west of the Andes shared the same Pfmsp1 block 2 MAD20-type allelic variant, despite showing high diversity for other genetical markers. Analysis of published data indicated that the prevalence of this allelic variant of a major vaccine candidate antigen was already dominant since 1998. This phenomenon, which had not been hitherto recorded for a malaria blood stage antigen, is of biological and immunological interest but remains unexplained.