2. School of Animal and Veterinary Sciences, the University of Adelaide, Adelaide, Australia.
3. Graduate, Faculty of Veterinary Medicine, Tehran University, Tehran, Iran.
4. Department of Clinical Sciences, Faculty of Veterinary Medicine, Tehran University, Tehran.
Background: The described pulmonary lesions are compatible with lesions previously described for maedi. In this study, one of the most important ovine slow viral infections is "Maedi disease" which was evaluated in Mashhad province.
Methods: During the study, ovine lung samples from 170 sheep (>1 year old) with their serum samples were collected in the Mashhad industrial abattoir. Initially, histopathological study for lung samples was carried out by providing H&E staining, serological test and an indirect ELISA on the serum samples. Histopathological study indicated all three lesions of Maedi disease in ovine lung which included smooth muscle hyperplasia (SMH) of alveolar walls, lymphofollicular hyperplasia (LFH) and interstitial pneumonia (IP). Furthermore, some involvement of each lung sample was estimated from mild-moderate and severe.
Results and discussion: Results of histopathological study demonstrated 45 cases (26.5%) and 15 cases (8.8%) with moderate degree and severe degree of involvement respectively. Liked-maedi disease included 60 cases (35.3%) of the whole ovine lung samples. Results of serological study showed 34 positive serums (20.0%). In addition, 15 cases (8.8%) of pulmonary lesions which were observed in histopathological study were equal and similar to the lesions previously described for maedi disease, and serological results confirmed them as well. However, there are some pathogens that can cause nearly pathological lesions like maedi in ovine lung.
Conclusion: This study showed that the pathogen causing maedi disease (maedi-visna virus) can be one of the pathogens causing chronic to subacute lymphoid interstitial pneumonia in Iran. Thus, study on histopathological and serological results correlation was performed.
Keywords: Maedi disease, histopathological, sheep, serological, abattoir