Drug susceptibility of Plasmodium falciparum from polyclonal isolates

Msp-1 and Msp-2 genes, each present as a unique copy in the genome of Plasmodium, contain polymorphic repeats in bloc 2. We studied allelic polymorphism of Msp-1 and Msp-2 by amplifying bloc 2 with a fluorescent primer, and analysing the fragment generated. We validated this method by mixing two cloned strains: chloroquine-susceptible HB3-Honduras and chloroquine-resistant FCM29-Cameroon. This method was then used to quantify the clones in natural isolates of 19 infected persons during quinine treatment. The fragment analysis method detects efficiently clone numbers and the proportions of each in isolates.