Evaluation of spatial and temporal contacts between tsetse flies and cattle, a key factor for trypanosomiasis transission in West Africa

Abstract

A global study was carried out in the agropastoral zone of Sideradougou (Burkina Faso) on risk assessment of trypanosomiasis transmission. Sentinel herds from two different farming systems were sampled and followed up during two years. The monthly incidences of infections were measured and interpreted according to the movements of herds, their practices for watering and their contacts with the riparian tsetse flies (Glossina tachinoides and G. palpalis gambiensis). In Nakaka, a Fulani breeders’ village 4 km away from the river, the parasites are transmitted during the dry season at the point of permanent watering places inside the forest gallery. In rainy season, the tsetse flies disperse through the savannah and infect cattle even in the village. In Pefrou, a group of farmers’ settlements, herds are made up mainly of draught cattle. Animals from settlements located near the hydrographic network drink in the river and are regularly infected all the year long. The incidences are higher during the rainy season and the beginning of the dry season when tsetse flies are the most abundant. On the other and, herds from the settlements far away (3 km) from the hydrographic network are watered from wells and do not frequent the habitats of vectors. In such an agricultural landscape, tsetse flies do not disperse even in the rainy season. Incidences in these herds are almost nil. These results prove the importance of space and temporal contacts between hosts and vectors in the epidemiology of trypanosomiasis in West Africa.