THE EPIDEMIOLOGY OF MALARIA IN PRABIS, GUINEA-BISSAU

This article reports upon a community survey of malaria in Prabis, Gui nea-Bissau. A house to house census of the population was initially ca rried out from August to December 1991(rainy season). After completing the census of each village, the population was invited to come, a wee k later to a central point, where they were medically examined and fin ger-prick blood samples were collected for epidemiological characteriz ation of the malaria situation in the area. The blood films of the one single village were used to compare the sensitivity and specificity o f Polymerase Chain Reaction (PCR) with optical microscopy detection of parasites. In another village, the occurrence of parasitaemia was com pared in children with and without fever During the dry season, from M arch to June 1992, the population in each village was again invited to come to a central point. Some of the field procedures were repeated. The study revealed Prabis as an administrative Sector of Guinea-Bissau with endemic malaria, mostly due to Plasmodium falciparum, but with a significant rate of mixed infections. Active transmission occurred th roughout the year but it was more intensive during the rainy season an d in the northwestern quadrant of the Sector The level of endemicity o f the villages varied from hypo to holoendemic. The factors associated with the differences among villages included village size and predomi nant economic activity (closeness to rice fields). The transmission pa radigm was, most likely, a mixture of malaria of the African wet Savan nah and malaria associated with irrigated paddy fields. PCR proved to be a sensitive method with low specificity during the dry season. Pyra exia of 37.4 degrees C or higher in children aged 2-9 years is not a s ensitive indicator of parasitaemia but, it is highly specific and it h as a clinically useful predictive value.