[Leukemia in sheep on a state farm]

Leukosis was diagnosed in a flock of sheep. It was studied epizootiologically, clinically, morphologically, virologically, and serologically in the course of two years. Fifteen sheep manifested clinical symptoms of the disease. Involved were the lymph nodes (superficial, skeletal, and visceral), liver, spleen, heart, and kidneys. Histologically, there were diffuse or limited lymphoid cell proliferations, some of them showing small unreactive cell elements. Sixty-two out of 160 serologically studied sheep showed in their sera antibodies against the virus of bovine leukosis as established by means of the agglutination immunodiffusion test. The leukosis virus was obtained from lymphocyte cultures isolated from infected sheep. It was used in the production of an antigen. A specific precipitation line was produced in the interaction between the sheep leukotic antigen and the bovine leukotic serum in the agglutination immunodiffusion test. Such data spoke of the antigenic similarity between the virus isolated from leukotic sheep and the virus isolated from leukotic cattle. The slaughterhouse inspection of 157 clinically normal sheep revealed tumoral lesions in 4 more animals. The changes were seen in the lymph nodes. No such changes were observed in the parenchymal organs.