Assessment of α-cypermethrin Pour-on Application and Diminazene Aceturate for the Treatment of Trypanosome-related Diseases Caused by Tsetse Flies in Cattle in Mô (Togo)

BackgroundThe effects of tsetse-transmitted trypanosomosis control in high tsetse challenge and trypanocidal drug resistance settings remain poorly understood in Togo, owing to the poor data underlying the current disease impact. This study was implemented in the framework of the PDRI-Mô project which is an African animal trypanosomosis control project using trypanocides and insecticides on cattle. This project, planned by the agricultural ministry, focused on all the sedentary cattle breeds in the 1000 km² area of the prefecture of Mô. Until 2013, the locality remained unconnected to outside areas, with long-term limited access to quality medicines, veterinary services, animal husbandry and new AAT control technologies. Methods From March 2014 to November 2017, a database of zoo-sanitary surveys integrating the evolution of the incidence of the disease and the coverage of interventions made it possible to quantify the apparent effect attributable to control effort in herds. The strategy involved an initial phase with cross-sectional entomological and parasitological surveys, including a rapid trypanocidal drug sensitivity testing. Treatment efficacy was assessed using parasitological status post-treatment of trypanosome-positive animals in each village, randomly assigned to three groups, one treated with 0.5 mg/kg b.w. Isometamidium chloride, the second with 3.5 mg/kg b.w. Diminazene diaceturate and the third with distillated water as control. Using parasitological status of blood sample collected on day 0, day 14 and day 28 post-treatment as the outcome result, trypanosome phenotype resistance of drugs treatment was determined if relapse occur. Then, three times a year, 20% of the herd received α-cypermethrin pour-on, and parasitaemic cattle with poor health were individually given diminazene aceturate at 7 mg/kg of body weight (b.w.).ResultsThe tsetse density in the area decreased significantly (P-value ˂ 0.001) from 1.78 ± 0.37 in March 2014 prior to the α-cypermethrin application to 0.48 ± 0.07 in February 2017. Prior to the trypanocidal treatment, relapse of trypanosome infections in the cattle was approximately 12.5% for diminazene at 3.5 mg/kg of b.w., 35% for isometamidium at 0.5 mg/kg of b.w. and null for diminazeen at 7 mg/kg of b.w. Target deployment led to the largest reduction in disease incidence from 28.1% in 2014 to 7.8% in 2017, an improvement in haematocrit from 24.27±4.9% to 27.5±4.6% and a reduction in calf mortality from 15.9±11% to 5.9%.ConclusionsImproving the access to these interventions for different types of livestock and maintaining their effectiveness in the face of high tsetse challenges should be the primary focus of control strategies in areas of Togo.