IN-VITRO SUSCEPTIBILITY OF TANZANIAN WILD ISOLATES OF PLASMODIUM-FALCIPARUM TO ARTEMISININ, CHLOROQUINE, SULFADOXINE PYRIMETHAMINE AND MEFLOQUINE/

A 30-h in vitro susceptibility test of Plasmodium falciparum mild isol ates to artemisinin, chloroquine, sulfadoxine/pyrimethamine and mefloq uine was performed in Kibaha, Tanzania. A sigmoid E-max model was fitt ed to all data for each isolate and drug combination. Artemisinin and mefloquine exhibited 100% growth inhibition against all isolates teste d (n = 69-74). The EC50 values for artemisinin and mefloquine were 14 and 146 nM respectively. Chloroquine and sulfadoxine/pyrimethamine res istance was 30% and 13% respectively. Susceptibility parameters (EC50, 90,95 and (99) values and s) varied between compounds and isolates ind icating the different sensitivity of P. falciparum isolates. No correl ation between susceptibility parameters of artemisinin and the other c ompounds was found. The high in vitro activities of artemisinin and me floquine indicate their potential role for the treatment of multidrug- resistant malaria in Africa.