Detection of the dihydrofolate reductase-164L mutation in Plasmodium falciparum infections from Malawi by heteroduplex tracking assay.

Standard polymerase chain reaction methods often cannot detect drug-resistance mutations in Plasmodium falciparum infections if the mutation is present in < or = 20% of the parasites. A heteroduplex tracking assay was developed that can detect dihydrofolate reductase 164-L mutations in variants representing 1% of the parasites in an individual host. Using this assay, we confirmed the presence of the mutation in P. falciparum infections in Malawi.