Chloroquine treatment of uncomplicated Plasmodium falciparum malaria in Mali: Parasitologic resistance versus therapeutic efficacy

Whether and when to replace chloroquine with other antimalarial drugs is an urgent public health question in much of Africa, where Plasmodium falcipar um, which is increasingly resistant to chloroquine, continues to kill milli ons each year. Antimalarial drug efficacy has traditionally been measured a s parasitologic resistance, but recent guidelines use both clinical and par asitologic criteria to monitor therapeutic efficacy. To assess the new effi cacy protocol, we measured parasitologic and therapeutic outcomes in 514 pa tients treated with chloroquine for uncomplicated P. falciparum malaria in Mall. There was a general agreement between parasitologic and therapeutic o utcomes at two sites, with 13-17% parasitologic resistance rates and 10-15% treatment failure rates. However, the new protocol overestimated early tre atment failure rates (21-71% of cases classified as early treatment failure had sensitive or RI parasitologic responses), particularly where resistanc e was rare, and missed low-level parasitologic resistance. Modifications of the protocol for monitoring antimalarial therapeutic efficacy are recommen ded.