Plasmodium vivax apical membrane antigen 1I-II from Nicaragua (2012-2013): genetic and antigenic polymorphism

OBJECTIVEGenetic and antigenic polymorphism of P. vivax apical membrane antigen-1 (pvama1I-II) from Nicaragua was examined.MATERIALS AND METHODSInfected blood samples from patients were obtained during 2012-2013. A gene fragment comprising domains I-II was amplified and sequenced, and the genetic parameters, haplotype relationships, genetic structure, and amino acid variation in predicted B cell epitopes were analyzed.RESULTS65 sequences of pvama1III had 19 nonsynonymous and five synonymous nucleotide changes. Nicaraguan parasites had low diversity, high linkage disequilibrium, and few recombination events. Neutrality tests indicate a positive and divergent selection, and three genetic clusters with loss of haplotypes were demonstrated. Amino acid variation predominated in predicted B cell epitopes and was closely related to that in Latin American parasites.CONCLUSIONSNicaraguan P. vivax is a moderately differentiated population under contraction and focalization processes, and the antigenic diversity resembles that of Latin American parasites. This information is relevant for vaccine development and epidemiological surveillance.