Bovine trypanosomosis in Gimbi district of Western Oromia, Ethiopia

Abstract

Abstract A study on the epidemiology of bovine trypanosomosis was conducted from September 2006 to April 2007 in six villages of the Gimbi district in west Wollega zone of Ethiopia. The prevalence of the disease, the apparent densities and distribution of tsetse and other biting flies in two seasons, the dry and rainy, were determined. The results of a questionnaire survey from 80 farmers revealed that trypanosomosis was a major health problem affecting animals and impeding agricultural activities.A total of 568 blood samples were collected from randomly selected animals (280 animals in rainy and 288 in dry season) and revealed the presence of Trypanosoma congolense Broden, 1904 and T. vivax Zieman, 1905 in the area. Trypanosoma congolense was the dominant species that accounted for 66.2% of the infections. The mean packed cell volume (PCV) concentrations were 22.77% (95% CI =19.99-21.55) in parasitaemic and 25.25% (95% CI=24.88-25.61) in aparasitaemic animals with a significant difference (P<0.005). There was a significant (P<0.012) difference in trypanosome infection between age groups of cattle, being higher in adults. The overall prevalence of trypanosomosis was 12.5%, while the disease prevalence was higher during the rainy season (15 %) than the dry season (10.1%). In three villages of lowland areas (below 1600 meter above sea level), a higher prevalence was recorded 20.9% and 7.9% as compared to three villages of midland areas (≥ 1600 meter above sea level) 11.8% and 8.3% in late rainy and dry season, respectively.A fly-survey was conducted by using 80 monoconical pyramidal traps and revealed that two tsetse species, namely Glossina morsitans submorsitans Newstead and Glossina tachinoides Westwood were found along with other biting flies (Tabanus, Haematopota and Stomoxys species). Higher numerical catches of Glossina were recorded in late rainy season and the apparent density was positively correlated (r=0.5171) with the prevalence of infection.