[Diversity of feeding behavior of Glossina palpalis palpalis in the forest belt of the Ivory Coast: relation to the prevalence of human African trypanosomiasis].

The feeding habits of Glossina palpalis palpalis, the main vector of human African trypanosomiasis (HAT) were retrospectively analysed using data collected between 1984 and 1994 in five areas in the forest belt in the mid-west of Côte d'Ivoire. The authors compare the feeding habits of the vector in these different foci. This analysis is aimed at determining if there is any relationship between the feeding pattern of tsetse-flies and the prevalence rates of HAT. The feeding pattern was measured using two indices: the conventional index of Shannon and Weaver (Ish) and a new one, the zoophily/anthropophily index (Za). The latter is an estimate of the ratio of the percentage of animal blood meals divided by the percentage of human blood meals. There was no correlation between apparent density and prevalence rate. A high Ish and a high Za were observed in the foci of Vavoua, Zoukougbeu and Sinfra where prevalence rates of HAT were high. Conversely, a low Ish and a low Za were observed in the hypoendemic areas of Daniafla and Gagnoa. Both indices are highly but not significantly correlated with prevalence rates. The Za index seemed to be more strongly correlated to the disease rate as compared to the Ish index. The epidemiological significance of these observations is discussed.