Bovine and equine trypanosomosis in Northwest Ethiopia: Prevalence, density of vectors and control measures

Abstract

A cross-sectional study was carried out from November 2016 to May 2017 in selected districts of Northwest Ethiopia (Jawi, South Achefer, Dembecha and Jabitehenan) with the aim of determining the prevalence of bovine and equine trypanosomosis, estimating the apparent density of vectors and assessing the effectiveness of control measures of the disease. A total of 1257 animals of which 803 bovine and 454 equine were examined for the determination of prevalence using blood sample collected from ear vein of animals. The buffy coat technique was employed to determine the prevalence and the packed cell volume (PCV) value. During sampling animals were categorized into age, body condition score, sex and hair coat color. A total of 40 monoconical traps 10 per district were deployed to estimate the apparent density of vectors. To assess control measures representative number of farmers were interviewed with a prepared questionnaire and using secondary data from veterinary offices. The overall prevalence of trypanosomosis was 7.47% and 4.40% for bovine and equine species, respectively. The prevalence of bovine trypanosomosis was 9.46%, 6.13%, 8.11% and 5.98% while prevalence in equine was 7.8%, 5.3%, 2.7% and 1.8% in Jawi, South Achefer, Dembecha and Jabitehenan districts, respectively. Significance differences in the prevalence of trypanosomosis were observed in hair coat color, age and body condition score in bovine while only body condition was significant in equine. The mean PCV value of parasitemic animals was significantly (P < .001) lower than that of aparasitaemic animals. The apparent densities of vectors were 1.04, 0.97, 0.32 fly/trap/day for Glossina, Stomoxys and Tabanus respectively. Glossina m. submorsitans and G. tachinoides were the species of tsetse identified. The questionnaire response indicated that trypanosomosis was found to be a serious constraint on livestock health in the study areas. The application of continuous trypanosomosis control measures particularly in Jawi and South Achefer districts which were showed an increasing trend in livestock number might be attributed to control effectiveness. In conclusion the presence of trypanosomes and potential vectors necessitate the application of sustainable and integrated control methods in the study areas.