Pulmonary carcinoma (Jaagsiekte) of sheep: Pathologic findings and comparison in multiple-case and case-free herds

During a 2-year intensive study of 3 herds of sheep, alveolar cell carcinoma (lung carcinoma, pulmonary adenomatosis, jaagsiekte) occurred in only 1 herd. This herd also had the highest incidence of various other diseases, such as verminous pneumonia, lung abscesses, chronic interstitial pneumonia, and mediastinal lymphadenitis due to Corinobacterium ovis. Hyper-7S immunoglobulinemia as defined by ultracentrifugal and immunoelectrophoretic analyses was used to indicate diseased animals. In the highly diseased herd, 46 of 550 animals were “hyperimmune.” Postmortem examination of 16 diseased animals revealed 9 jaagsiekte cases and 7 other diseases. The other 2 herds each with 350 animals were “case free.” Virus-like particles, similar to the murine C-type virions, were observed in the primary tumor tissue.