[Prevalence of malaria in Ouagadougou and the surrounding rural environment during the period of maximal transmission].

The prevalence of malaria infections was estimated in six different areas of the town of Ouagadougou, Burkina Faso, and in three neighbouring villages. Thick and thin blood films from a total of 2,117 children less than 5 years old were examined at the peak of the transmission season (August-September). Plasmodium falciparum was found in more than 98% of the positive slides. The overall parasite index at Ouagadougou was 16%, while indices from 51 to 88% were recorded in the three villages. Significant differences were observed between the six urban areas within the town as well as between the three villages. The highest parasite rates in the town were clearly associated with major breeding places of An. gambiae s.l. indicating a remarkable focality of transmission. Significant differences were observed between groups of children from houses only 300 m apart. Chemoprophylaxis appears to play an important role in determining parasite rates lower than expected in one of the three villages.