Evaluation of risk factors of animal trypanosomosis in Ghana, and the monitoring of the impact of disease and vector eradication intervention in the Upper West Region of Ghana

African animal trypanosomosis (AAT) is a major constraint to viable and sustainable livestock production systems in Ghana. Under the umbrella of the Pan African Tsetse and Trypanosomosis Eradication Campaign (PATTEC), Ghana is collaborating with Burkina Faso in a sub-regional initiative aiming at creating tsetse-free areas across their common borders. The objective of this thesis was to conduct research to guide project implementation and specifically seeks to i) determine the pre-intervention vector and disease situation of the intervention area, ii) determine tsetse population structuring and the consequences on sustainable tsetse control efforts, iii) evaluate SAT for the control of riverine tsetse species in Ghana and iv) evaluate the environmental risk of the intervention programmes. Results of a baseline survey conducted in the Upper West Region (study area) indicated a wide-spread prevalence of Glossina tachinoides but Glossina palpalis gambiensis was limited to the southern edge of the study area. Average parasitological prevalence in cattle was estimated at 2.5% (95% CI: 1.06–5.77) and serological prevalence measured at 19% (95% CI: 14.03–25.35). The mean Index of Apparent Abundance (IAA) of tsetse was 8.7, 1.9 and 1.3 for samples taken along the Black Volta, Kulpawn and Sissili Rivers, respectively. Investigations of the G. tachinoides populations confirmed significant strucring within and between the three main river-basins of the study area, and indicated a local density of 0.048-0.061 flies/m² and dispersal distance that approximated 11 m per generation [CI 9 - 17]. No significant sex-biased dispersal was detected. However, the observed dispersal was deemed sufficient for a G. tachinoides-cleared area to be reinvaded from neighbouring populations in adjacent river basins The potential of Sequential Aerosol Technique (SAT) to eliminate riverine tsetse species in a challenging subsection (dense tree canopy and high tsetse densities) and the subsequent efficacy of an integrated strategy, one year after the SAT operations, were also investigated. Results indicated failure to achieve elimination, attributed to insufficient penetration of insecticide aerosols in thick riverine forest galleries. However the overall reduction rate due to SAT was important (98%) and the subsequent integrated strategy maintained high levels of tsetse suppression. Finally an environmental impact assessment revealed no significant impact of deltamethrin aerosols on non-targeted aquatic and terrestrial arthropods. (Résumé d'auteur