Application of genetic markers to the identification of recrudescent Plasmodium falciparum infections on the northwestern border of Thailand

Abstract

Parasite genotyping by the polymerase chain reaction was used to distinguish recrudescent from newly acquired Plasmodium falciparum infections in a Karen population resident on the northwestern border of Thailand where malaria transmission is low (one infection/person/year). Plasmodium falciparum infections were genotyped for allelic variation in three polymorphic antigen loci, merozoite surface proteins-1 and -2 (MSP-1 and -2) and glutamate-rich protein (GLURP), before and after antimalarial drug treatment. Population genotype frequencies were measured to provide the baseline information to calculate the probability of a new infection with a different or the same genotype to the initial pre..