The study on tsetse fly (Glossina species) and their role in the trypanosome infection rate in Birbir valley, Baro Akobo River system, western Ethiopia

The study was conducted in Birbir valley of Oromia Regional State, Western Ethiopia from November, 2009 to July, 2010 to determine the trypanosome infection rate ofGlossina species and to relate with season tsetse population density and epidemiology of bovine trypanosomosis. A total of 384 flies of four species were dissected. The overall infection rate of Glossina species was 5.98% among which 4 (1.04%) was male and 19 (4.94%) were female flies. The prevalence was significantly higher (c2 =26.04; P = 0.00) in female flies than male flies. Higher infection rates (5.46%) were observed in the morsitans group (Glossina pallidipes and Glossina morsitans) than the palpalis group (0.52%), (Glossina fuscipes and Glossina tachinoides). In determination of tsetse flies population density, flies were trapped using baited stationary traps and apparent density; species of tsetse flies and other biting flies were estimated in relation to season, altitude levels, vegetation types and traps in selected sites of the study area. Higher proportion of tsetse flies was caught in the riverine vegetation type followed by savanna, forest, bush, and cultivated areas. Designing and implementation of tsetse control should be targeted on the major cyclical vectors of the savannah tsetse flies (G. morsitans and G. pallidipes) rather than controlling the whole species, hence the cost of tsetse control and the time of operation will be reduced.   Key words: Cattle, epidemiology, Glossina species, infection rate, trypanosomosis, Western Ethiopia.