ABSTRACT
Out of a sample of 200 rumens from sheep slaughtered in Edinburgh, papillomas were found in 25. They occurred as fibro-papillomas, mostly along the pillar of muscle between the dorsal and ventral rumen, and were often multiple. No inclusion bodies were seen in the lesions or papilloma virus particles on electron microscopy. Homogenisation of papillomatous tissue followed by various methods of purification did not yield identifiable virus particles, and viral DNA was not detected. Immunoperoxidase staining showed a very small number of positive cells at or on the surface of 6 out of 10 lesions examined. Thus, it seems probable that virus particles are not found in large numbers in the rumen papillomas of sheep, unlike the situation in ovine skin warts, but are present in a few epithelial cells which are rapidly shed from the surface of the mucous membrane.
