[Stegomyian indices and epidemiological status of yellow fever in a rural area of the Ivory Coast].

The M'bahiakro region, located in the center of Ivory Coast and inhabited by the N'gain, has been the scene of a yellow fever epidemic since 1982. This region reunites all the conditions for cyclic emergence of the flavivirus given the current epidemiologic pattern of yellow fever in Africa. In view of this situation ORSTOM, in collaboration with the Pasteur Institute of Ivory Coast, has created a pilot zone for epidemiologic surveillance of yellow fever in this region. The N'gain region which has a total population of 12,000 living in 20 villages with between 100 and 2000 inhabitants is located in a preforest area with an attenuated transitional climate characterized by a dry season and a rainy season with two peak periods of precipitation (May and October) but a low mean annual rainfall (1172 mm). There are few springs, wells and rivers and maintaining water supplies is difficult. As a result villagers stockpile rainwater in various types of containers. Inspections were carried out from February to July in the 20 villages of the region. Each room of every dwelling was registered and visited. Water reserves were inspected and those containing pre-imaginal stage Culicidae were counted as positive. Nymphs and larva were sometimes collected. Nymphs were raised and larva preserved. Species identification by the laboratory was based on these larva and imagos obtained by raising the nymphs. Correspondence tables established by the World Health Organization between stegomiyan indices (dwelling), container, BRETEAU) and flavivirus in the population were used to exploit the results.(ABSTRACT TRUNCATED AT 250 WORDS)