Epidemiology of Sheep Lice and Efficacy Evaluation of 60% Diazinon and 1% Ivermectin against Bovicola ovis in Sayint District, South Wollo, Ethiopia

Abstract Background Sheep lice, caused by Bovicola ovis are very common in Ethiopia. It can result decreased production and reproduction, downgrading and rejection of skins in tannery industries. A cross-sectional and experimental study were conducted in Sayint District, South Wollo, Ethiopia which aims to determine the prevalence of sheep lice with the associated risk factors, identify the major sheep lice species and evaluate the efficacy of 60% Diazinon and 1% Ivermectin against Bovicola ovis. Study kebeles and animals were selected using purposive and multistage sampling techniques. Accordingly, a total of 232 sheep were sampled to estimate the prevalence of sheep lice. Fifteen sheep for in-vivo and 80 Bovicola ovis lice for in-vitro test were used for drug efficacy trial, by using completely randomized design. Results The overall prevalence of sheep lice in this study was 48%. Hair length (OR = 2, P = 0.00), body condition (OR = 1.9, P = 0.02), agro ecology (OR = 1.19, P = 0.00) and season (OR = 2, P = 0.01) were significantly (P < 0.05) associated with sheep lice infestation. The dominant sheep lice species in the study area were Bovicola ovis with prevalence of 83% and mixed infestation of 17% Bovicola ovis with Linognatus ovillus. In this study, the efficacy of 60% Diazinon and 1% Ivermectin against Bovicola ovis were 97% and 81%, respectively. Conclusion The overall prevalence of sheep lice infestation in the present study area was higher, in which Bovicola ovis was predominant and resistant against 1% Ivermectin. Therefore, tailor made intervention is required with a view to reducing the prevalence of sheep lice infestation and addressing drug resistance in the study area.