[Incidence of African trypanosomiasis and the density of settlements in the forests of Côte d'Ivoire: the possibility of predicting high risk areas for surveillance of disease reservoirs].

In the forests of Côte d'Ivoire a surveillance network is needed to quickly and continuously detect cases of Human African Trypanosomiasis (HAT). This requires knowledge of high risk areas, and thus of an appropriate epidemiological indicator. Study of several HAT foci in Côte d'Ivoire shows a striking correlation between epidemiological risk and settlement density by square kilometer (r = 0983; P < 0.05). Epidemiological risk and disease incidence will increase up to the point when human influence eradicates the vector. This hypothesis is supported by the correlation between settlement density (d) and cumulative incidence: i = 0988 d - 0967 (r = 0.951). The prevalence would be 0.5% from 1.5 settlements per km2, and 1% from a density of 2. The first results of remote sensing indicate that it is possible to identify forest areas where settlement density has reached a critical level.