Study on Spatial Distribution of Tsetse Fly and Prevalence of Bovine Trypanosomosis and other Risk Factors: Case Study in Darimu District, Ilu Aba Bora Zone, Western Ethiopia

Abstract

African Animal Trypanosomosis is one of the major impediments to livestock development and agricultural production in Ethiopia, which negatively affect the overall development in agriculture in general, and to food self-reliance efforts in particular.  Currently, about 180,000 to 200,000km² of fertile arable land of west and southwest of the country is underutilized. Darimu district is one of the areas with such problems. Therefore, a cross-sectional study was conducted with the objectives of assessing the prevalence of Bovine Trypanosomosis and determines spatial distribution and apparent density of tsetse and other biting flies in the study area. In current study, a total of 650 blood samples were collected from randomly selected animals and subjected to Buffy coat parasitological laboratory technique and positive samples were subjected to thin blood smear followed by Giemsa staining. Out of the total blood sampled, 7.1% tested positive for trypanosomosis. Out of positive cases, Trypanosoma congolense (82.61%) was the dominant trypanosome species followed by mixed infection (Trypanosoma congolense and Trypanosoma vivax) (8.67%). Infection with Trypanosoma vivax and Trypanosoma brucei were equally prevalent 4.35% (2/46). Statistically significant difference (P<0.05) was observed in the prevalence among the species of trypanosomes. Trypanosomosis prevalence based on body conditions were found to be: 11.43%, 5.40% and 4.16% in poor, medium and good body condition, respectively and there were statistically significant difference (P<0.05) in infection rate among animals of different body conditions. The mean packed cell volume (PCV) values of parasitaemic and aparasitaemic animals were 21.18+2.91 and 28.28+3.82, respectively and was  statistically  significant (P<0.05). Furthermore, for entomological survey, a total of 1170 flies were caught by deploying 70 monopyramidal shaped traps. Of these flies, 962 (82.22%) were Glossina, whilst the remaining flies were either Stomoxys (12.56%) or Tabanus (5.21%). The overall apparent densities of tsetse flies, Stomoxys and Tabanus were 6.87 f/t/d, 1.05 f/t/d and 0.44f/t/d, respectively. Generally, this survey showed that despite frequent control strategy is implemented; trypanosomosis is still a core problem for livestock production in the study area. Therefore, the current control strategies implemented in the area should be assessed and integrated disease and vectors control approaches should be practiced.

Keywords: Prevalence; Bovine Trypanosomosis; Buffy coat; Spatial distribution, Tsetse fly; Darimu