Concurrent infection of Maedi-Visna with lung worms and pulmonary adenomatosis in sheep kept in Debre Berhan Sheep Improvement Station, Central Ethiopia

The study was conducted with the objectives of determining the possible causes of pneumonia in the sheep and to characterize the microscopic lesions of concurrent infection of Maedi-Visna with lung worms and other infectious pneumonia. Detailed gross and microscopic examinations were employed on 35 Maedi-Visna seropositive sheep. Out of 35 sheep slaughtered and examined for gross lesions on their lungs, lung worms, fibrinous adhesions, and mottling on the cranioventral lobes were observed with decreasing order of frequency. Histopathologically, the pneumonic lungs (n = 35) revealed Maedi (100%), Maedi-Verminous pneumonia complex (28.57%, n = 10), Maedi bronchopneumonia complex (17.14%, n = 6), and Maedi-pulmonary adenomatosis complex (2.86%, n = 1). The occurrence of high proportion of concurrent infection of Maedi-Visna with lung worms and bacteria strongly suggest synergy of the pathogens and the presence of several stress factors including wind draft, unusually chilly weather and poor management in the area that are known to predispose the improved sheep breeds to respiratory disease complex. On top of culling by slaughter of Maedi-Visna seropositive sheep, regular deworming, redesigning the house, and vaccination of sheep with the available vaccines should be carried out timely at least to reduce the severity of Maedi-Visna induced loss.