INVITRO RESPONSE OF PLASMODIUM-FALCIPARUM TO CHLOROQUINE IN THE NANDI DISTRICT, KENYA

Abstract

Isolates of P. falciparum from Nandi district, Kenya, which were tested for their sensitivity to chloroquine using the WHO in vitro macrotechnique, yielded a total of 29 successful tests, one of which showed overt resistance with schizont maturation at chloroquine levels of > 1.5 .times. 10-6 mol/l. The majority of isolates showed reduced sensitivity to chloroquine, and the EC99 [99% effective concentration] was 1.7218 .times. 10-6 mol/l. These findings are indicative of widespread in vitro resistance of a low degree which may remain largely unnoticed in immune individuals. However, in nonimmune subjects one may expect also in vivo resistance because the parasites will not be completely cleared after a normally curative dose of chloroquine.