SEASONAL PREVALENCE OF BOVINE TRYPANOSOMOSIS AND VECTOR DYNAMICS IN SELECTED SITES OF WESTERN SIDAMA, SOUTHERN ETHIOPIA

Abstract

Trypanosomosis is a serious and often fatal disease of livestocks mainly in the rural poor community and rightfully considered as a root cause of poverty in the country. The temporal information about the prevalences of trypanosomosis and apparent density of flies are crucial for the design and implementation of the appropraite prevention and control measures. Therefore, the objectives of this repeated cross-sectional study conducted from December 2022 to October 2023 in selected sites of Western Sidama, Southern Ethiopia was to estimate the seasonal prevalence of bovine trypanosomosis and the apparent density of flies in the study area. A total of 480 systematically selected cattle from Chirecha, Fokabadelecha, and Tulito Kebeles were sampled in the dry and wet seasons of the study period. To estimate Trypanosoma infection, the buffy coat technique was used on blood samples collected from the marginal ear vein of the cattle. Out of the 480 cattle, 30 were found positive for trypanosomosis, resulting an overall prevalence of 6.3% (95% CI: 4.4-8.8; OR: 1.54). The wet season showed a relatively higher prevalence (7.5%, 95% CI: 4.8-11.6) than the dry season (5.0%, 95% CI: 2.9-8.6), although the difference was not statistically significant. The prevalence was significantly higher in Chirecha Kebele (12.0%, 95% CI: 8.1-17.4; OR: 6.4) and in black-coated cattle (19.4%, 95% CI: 9.4-35.8; OR: 6.84) (p<0.05). Two species of Trypanosoma, T. congolense (80%) and T. vivax (20%), were identified. The hematological finding found significantly lower mean PCV values in parasitemic animals (21.1±3.39) than aparasitemic animals (26.30±5.23). Out of 256 total flies caught by using 40NGU traps in the dry and wet seasons, 79(30.9%) were G. pallidipes, 56(21.9%) were Tabanus, and 121(47.2%) were stomoxys. The overall apparent density of G. pallidipes was 0.99 f/t/d with relatively higher density in the wet (1.95f/t/d) than the dry (0.025f/t/d) season. In conclusion, the study revealed bovine trypanosomosis and its vectors are widespread in the study area. To reduce the prevalence of trypanosomosis, particularly in high-risk areas such as Chirecha Kebele and black-coated cattles, control measures such as the use of traps, targets, deltamethrin, and trypanocidal drugs should be consolidated.