Prevalence of African animal Trypanosomiasis in cattle in the livestock-wildlife interface area of Semliki National Park

Abstract

African Animal Trypanosomiasis (AAT) is one of the biggest disease problems in Uganda, posing a big threat on livestock production due to its implications on productivity through reduced milk production, emaciation, reduced breeding potential, among others. Recently, information has indicated that the AAT prevalence is relatively higher in and around conservation areas and water bodies although accurate estimates of the prevalence of AAT has been curtailed by absence of quick disease detection tools, as diagnosis of AAT in Uganda is majorly based on clinical signs which are sometimes similar with other livestock diseases. For this reason, this study was intended to estimate the prevalence and assess the extent of the trypanosomiasis challenge around Semliki National park by using a recently developed novel rapid serological antibody diagnostic tool. This cross-sectional study was carried out in 13 villages purposively selected in Ntoroko district that were neighboring Semliki National park. The villages were distributed within 6 sub-counties that had earlier raised complaints to the district authorities and subsequently to the Coordinating Office for Control of Trypanosomiasis in Uganda (COCTU) about high levels of tsetse flies and trypanosomiasis among cattle. Whole blood from the ear vein was dropped onto the RDT using a capillary tube, which displayed results within 15 minutes and results recorded onto Excel sheets. A total of 663 heads of cattle including 540 females and 123 males were randomly sampled and screened for trypanosomiasis, and the novel RDT revealed 523 cattle positive and 140 negative. Of the 523 positives obtained, 89 were positive for T. vivax, 298 were positive for T. congolense and 136 positive for both T. vivax and T. congolense; 432 (65.2%) females and 91(13.7) males tested positive. The overall prevalence of AAT in the Semliki region was found to be 78.9%, with Kibiira village having the highest prevalence, and Kakindu village having the lowest. T. congolense was the most prevalent strain in this area, indicating high concentration of tsetse fly vectors in the region and thus need for immediate control. Prevalence was seen to be much higher in Females than males, and also predominantly in weaner cattle than other age groups, which was found not to have any significant association to the prevalence of trypanosomiasis in this area. The high prevalence of AAT revealed by the RDT could be attributed to expression of both active and non-active infections by the antibody test, which indicates prior exposure of the animals to either one or both strains of trypanosomes, and therefore the immediate need for either prophylactic or curative approaches against trypanosomiasis in all the cattle in this area.