Extensive papillomatosis of the bovine upper gastrointestinal tract.

Extensive papillomatosis was identified in a heifer born and raised in Scotland and a steer born and raised in England. In both cases, the papillomas extended from the mouth and tongue to the reticulum. Although cases of florid papillomatosis of the upper gastrointestinal tract occur relatively frequently in cattle grazing on bracken fern in the Scottish Highlands, no such cases have been reported previously in English cattle. Histopathological examination of the papillomas showed that the lesions were wholly epithelial, with acanthosis, hyperkeratosis and the pathognomonic koilocytes characteristic of papillomavirus infection. Bovine papillomavirus type 4 (BPV-4) was identified by molecular amplification and sequencing of the viral genome.