A national survey of the prevalence of chloroquine resistant Plasmodium falciparum in Burkina Faso.

Plasmodium falciparum susceptibility to chloroquine was investigated in 10 areas of Burkina Faso in the rainy seasons in 1990-1991. The 7-days in-vivo test was carried out from August to November on children aged 2-8 years with monospecific P. falciparum infection (asexual parasitaemia > 800 microliters-1 of blood), axillary temperature < 37.5 degrees C, and a negative Bergqvist urine test for 4-aminoquinolines. Among 2190 children screened, 366 were selected. Blood samples were collected on days 0, 2, 4 and 7 by finger-prick, and 100 microscopic fields of thick and thin smears were examined for parasite density and species identification. Chloroquine was given under supervision at the standard dose of 25 mg kg-1 over three days (days 0, 1 and 2) with an observation period of one hour after treatment. Parasitaemia did not clear in 63 cases (17.2%) with a 13.4% RII response and 3.8% RIII response. The results do not seem to indicate a decline in the sensitivity of P. falciparum to chloroquine in Burkina Faso during the past two years.