Chloroquine resistant Plasmodium falciparum in coastal Tanzania. A challenge to the continued strategy of village based chemotherapy for malaria control

An in vivo study to assess Plasmodium falciparum sensitivity to chloroquine was conducted in two villages of the Bagamoyo District, Tanzania in December 1992. The WHO standard field test (7 days) and the extended test (28 days) were carried out on symptom free children. The presence of chloroquine resistance was confirmed with 59% of infections being found resistant. Fifty-three percent were R(I), 2% were at R(II) and 4% at R(III) levels of resistance. Dosage was 25 mg/kg chloroquine base delivered over three days.