Chloroquine sensitivity of Plasmodium falciparum in Ibadan, Nigeria.

Thirty-five children with Plasmodium falciparum malaria were treated with 25 mg/kg chloroquine over three days and observed for seven days during which blood films were examined daily for malaria parasites. Asexual forms of P. falciparum which were present in the blood films of all the patients before commencing treatment disappeared rapidly from the blood so that by the third day no parasites were seen in the blood film. The blood films remained negative for the rest of the seven-day observation period. Plasma chloroquine determination in eight of the patients showed high blood levels during the first three days. The results do not confirm the suspicion of chloroquine-resistant P. falciparum in the area studied although RI level of resistance by WHO criteria was not excluded.