Assessment of Trypanocidal Drug Resistance In Tsetse Infested Areas of Guraferda District, Bench Maji Zone, South Western Ethiopia

Abstract

The South Western region of Ethiopia is affected by both tsetse and non-tsetse transmitted trypanosomosis with a significant impact on livestock productivity. The control of trypanosomosis in Ethiopia relies on either curative or prophylactic treatment of animals with diminazene aceturate (DA) or isometamidium chloride (ISMM). This study was conducted from March - June 2017, where tsetse infestation was high in four purposively selected rural kebeles of Guraferda district of Bench Maji Zone, South Western Ethiopia. The main objective of this study was to assess trypanocidal drug resistance under natural grazing systems. Resistance to trypanocidal drug was determined through longitudinal studies. In this study 200 cattle were used for experiment; 50 cattle from each rural kebeles (25 treated and 25 control group). However, 16 animals 5 from control and 11 from threated group were left due to sale of the animals by the owners, refusal of owners to allow their animals during sample collection and inability to reach the study kebeles because of heavy rain and presence of mud. In the present study, 25 cattle were treated with isometamidium and 25 cattle were left untreated and examined regularly at two weeks interval for the presence of trypanosomes. During the experimental period, all infections were monitored in both groups and treated with diminazene (7 mg/kg) body weight. Resistance to isometamidium was assessed by comparing cumulative incidence in both treated and control group using the test relative risk reduction and deducting the rate of treatment failure. Resistance to diminizene was assessed through the rate of treatment failure observed at two week post treatment in the control group. In both cases the threshold of 25% treatment failure was adopted as criteria of presence of chemo-resistance. The present study revealed that the prevalence of trypanosome infection was (76.8%) in control and (23.2%) in treated group. The trypanosome species in the area was predominantly due to T.Congolense (76.8%). This indicates there was a resistance of trypanosome species for the treatment with the recommended dose of diaminazine (7mg/kg) and isometamidium (1mg/kg) body weight. Thus, it is crucial to develop an adequate prophylactic measurements to reduce the prevalence of trypanosome infection there by reducing tsetse fly populations in the study areas.