Prevalence and Species Identification of Lungworms in Sheep and Cattle: A Postmortem Study in North Shewa, Central Highlands of Ethiopia

Lungworms are among the major nematode parasites causing significant impacts on livestock production, mortality and morbidity in young animals, and poor productivity in adult animals. Despite the widespread distribution of lungworms, there is little information in North Shewa in the central highlands of Ethiopia. Thus, a cross-sectional study was conducted to determine the prevalence of lungworms, identify the major respiratory helminths, and assess putative risk factors in sheep and cattle. A postmortem examination was conducted on 400 randomly selected animals. The present study revealed an overall 20.75% (95% CI: 16.88-25.06) prevalence of lungworm infection. The prevalence of respiratory helminths was 40.69% (95% CI: 33.88-47.77) in sheep and 0% in cattle. The logistic regression analysis indicated that age and season were significant risk factors, whereas body condition was a significant predictor of lungworm infections. Young sheep were 2.3 (95% CI: 1.26-4.23; <i>p</i>=0.007) times more at risk of lungworm infection than adults. The prevalence of the disease was 4 (95% CI: 1.79-8.72; <i>p</i>=0.001) times higher in sheep with poor body conditions. The prevalence of lungworm was more than 3 (95% CI: 1.37-6.62; <i>p</i>=0.006) times higher in autumn than in spring. The most prevalent species of respiratory helminths were <i>Dictyocaulus filaria</i> (29.9%; 95% CI: 23.71-36.69), <i>Muellerius capillaris</i> (4.41%; 95% CI: 2.04-8.21), mixed infections (3.92%; 95% CI: 1.71-7.58), and <i>Protostrongylus rufescens</i> (2.45%; 95% CI: 0.80-5.63). The present study determined a higher prevalence of ovine lungworms and no evidence of the disease in cattle. The study identified age, body condition, and season as the most important risk factors for lungworm infection. Thus, regular deworming of sheep and awareness creation for the farmers on rotational and strategic grazing are forwarded to control lungworms in sheep. Moreover, further studies are required to confirm the conditions of lungworms in cattle in North Shewa.