Testicular lesions in rams infected by maedi/visna virus

Pathological lesions were observed in the testicles of 5 out of 7 rams found to be infected by maedi virus serologically and by histopathological examination of the lungs. The interstitium of the testicles was infiltrated with lymphocytes, histiocytes and plasma cells. The infiltration was mainly perivascular and of varying severity, and was accompanied by fibrosis. The seminiferous tubules neighbouring the severely affected parts were atrophied and, as a result, in circumscribed areas of the testicles disturbances of spermatogenesis were observed. The epididymides were devoid of pathological changes. Studies are in progress to determine whether the testicular lesions are actually caused by maedi/visna virus. Transmission of the virus with infected rams' semen is possible.