Seasonal Dynamics and Associated Risk Factors of Bovine Trypanosomosis and Its Vector in Selected Districts of Gamo and Gofa Zones, Southern Ethiopia.

Abstract

BACKGROUND: Trypanosomosis is an economically significant livestock production constraint in 37 sub-Saharan African countries, including Ethiopia. Trypanosomosis requires a high annual budget to reduce Trypanosomosis infection and vector control. MATERIAL AND METHODS: A repeated cross-sectional study design was employed in four selected districts of the Gamo and Gofa zones to assess the prevalence of African animal trypanosomosis for over four years from 2019 to 2022, in dry and rainy seasons. About eleven kebeles were selected to bleed 2,567 cattle. Two hundred forty NGU traps were deployed for 2 days, 30 traps per season in each district, using a global positioning system (GPS). All cattle were local Zebu breed and were selected systematically from the eleven kebeles of the Zalla, Dara Mallo, Kucha, and Kucha Alfa districts. The risk factors recorded were analysed using Stata 14 software. RESULTS: The overall prevalence of bovine trypanosomosis across the study areas was 9.9% with a 95% confidence interval of 8.8%-11.1%. The responsible cause of Trypanosoma species was Trypanosoma congolense (84.3%), followed by mixed infections of T. vivax and T. congolense (11.1%), and T. vivax (4.7%). The study showed significant (p < 0.05) prevalence differences observed between districts, kebeles, altitudes, seasons, and study years using univariable logistic regression. Multivariable logistic regression analyses revealed that season, study year, skin coat colour, and body condition score were risk factors affecting bovine trypanosomosis in the study area. Infected and poor-body-conditioned animals showed significantly (p < 0.05) lower mean packed cell volume (PCV) than corresponding factors. The overall tsetse survey in wet and dry seasons showed proportions of 2075 (84.1%) and 386 (15.7%) Glossina spp. caught, with apparent densities of 8.65 and 1.61 flies per trap per day, respectively. CONCLUSION: The study findings showed that trypanosomosis and tsetse flies were high in the study area and influenced by the season and study locations. Therefore, the disease requires improved control action to alleviate the problem in the area.