Tsetse and African Animal Trypanosomiasis status; prevalence, spatial distribution, and implications to control trypanosomiasis in Uganda.

Abstract

African animal trypanosomiasis (AAT) transmitted by tsetse flies poses a threat to livestock in Uganda. The disease has been present in the country for many years. Mapping of the disease prevalence and vector spatial distribution in the country was undertaken to assess the situation. The disease has been endemic in the northern region of the country. Tsetse entomological surveys, AAT prevalence data together with environmental (climate, vegetation and topographical) explanatory data were used to map the presence and prevalence risk. Tsetse fly surveys were done and the vector was found mostly in areas north of Lake Kyoga and islands in Lake Victoria. Animal trypanosomiasis prevalence data was obtained from published works and samples collected and analysed during COCTU field operations. AAT was mostly prevalent in northern region. Through linear regressions, it was found that AAT prevalence was mainly significantly (P ≤ 0.001) contributed by temperature variance, precipitation of driest month, precipitation of the warmest quarter, precipitation of coldest quarter and recent annual mean precipitation climatic and vegetation cover. Tsetse flies trapped per day (FTD) were significantly (P ≤ 0.05) associated to precipitation of the wettest quarter, precipitation of coldest quarter and annual mean land surface temperature difference climatic factors. Topographical factor (altitude or elevation) did not influence the model outcome for both while vegetation didn't influence the vector model outcome. AAT and tsetse flies were widely prevalent in the northern and northeastern regions of the country (areas north and northeast of L. Kyoga). The risk reduced in areas south of the lake with the exception of areas around big water bodies and some conservation areas. These findings indicate that initiative-taking measures in vector and disease control should be directed towards the northern hemisphere of the country.