Persistence of low levels of Plasmodium falciparum resistance to chloroquine in the autochthonous population of the Central African Republic.

In Central African Republic, the first cases of resistant P. falciparum to chloroquine occurred in 1983 in non immune expatriate residents on regular chemoprophylaxis. From 1984 to 1991, 950 in vivo tests with a seven days observation period were performed in semi-immune autochtonous children living in seven towns of the country. Chloroquine treatments were given at 25 mg/kg over 3 days period to children with P. falciparum parasitaemia > 500 (634 simplified methods) or > 1000/mm3 (316 WHO standard field tests), usually asymptomatic. Until 1988, the surveys show an absence or a low frequency of chloroquine resistance (usually below 10%) according to the town; since 1989, the resistance has been present in all towns but everywhere with a frequency under 20%. None cases of R III level resistance was observed and all children became or remained asymptomatic at day 7. Until further surveys demonstrate a decreased efficacity of chloroquine, it is advised that chloroquine be used at 25 mg/kg over 3 days period as the treatment of choice in uncomplicated acute malaria in the Central African Republic.