Strong association, but incomplete correlation, between chloroquine resistance and allelic variation in the pfmdr-1 gene of Plasmodium falciparum isolates from India

The increasing prevalence of chloroquine-resistant Plasmodium falciparum ha s complicated the control of falciparum malaria. It has been suggested that point mutations at nucleotide positions 754, 1049, 3598, 3622 and 4234 in the parasite's pfmdr-1 gene are associated with such resistance, although t his is a matter of controversy. Eighteen chloroquine-sensitive and 22 resis tant isolates of P. falciparum from India were investigated, to examine the role of the pfmdr-1 gene in the resistance, and to determine whether any o f the point mutations could be used as a marker for the rapid identificatio n of the chloroquine-resistant strains. As this investigation failed to rev eal an explicit association between allelic variation in the pfmdr-1 gene a nd chloroquine resistance, the use of point mutations to identify the resis tant strains does not appear feasible.