A cross-sectional study of equine trypanosomosis and its vectors in Wolayta zone, Southern Ethiopia

Abstract

A cross-sectional study was conducted from October 2008-April 2009 in Humbo, Kindo koysha and Sodo zuria districts selected from Wolayta zone located in Southern Ethiopia to investigate the prevalence and species of trypanosomes infecting equines and identify the fly vectors playing a role in the transmission of trypanosomosis. Blood samples were collected from a total of 214 donkeys, 20 horses and 60 mules and examined by dark ground/phase contrast buffy coat technique and Giemsa-stamed blood smears. Accordingly, trypanosome species were only encountered in 10.7% of the donkeys (n = 23) while none of the horses and mules examined was positive for trypanosome infection. Two species of trypanosomes were detected in donkeys which in order of predominance were Trypanosoma congolense (52.2%) and Trypanosoma vivax (26.1%) and mixed infection by both species was found in 21.7% of trypanosome-positive animals. Statistical analysis showed no significant association between prevalence of trypanosome infection and the district, Body Condition Score (BCS), age and sex of donkeys (p>0.05 in all cases). There was a highly significant difference (p<0.0001) in mean PCV(%) between trypanosome infected and non infected donkeys. Similarly female animals had significantly lower (p<0.05) mean PCV (%) than male animals. No significant difference (p>0.05) was observed among the mean PCVs of donkeys infected with different species of trypanosomes. The entomological survey revealed the existence of a cyclical vector Glossina pallidipes and other biting flies with a relative proportion of 13.2 and 86.8%, respectively. In conclusion, the prevalence of trypanosomosis obtained in the current study is generally low compared to previous studies and this might be associated with reduction in tsetse density as a result of increased agricultural activities and tsetse control interventions being carried out by governmental and non-governmental organizations in the area. © Medwell Journals, 2010.