We wish to report an unusual presentation of bovine papular stomatitis virus (BPSV) infection of a single cow’s teat, which was the only clinically detected manifestation of this infection in a dairy herd. The affected animal was a five-year-old Holstein in its third lactation with an average yield of around 9500 litres in a closed herd of 227 Holstein cows on the Cheshire/Shropshire border. The cow presented with extensive proliferative scabby lesions of the entire right forequarter teat skin, which resulted in occlusion of the teat canal (Fig 1). The teat had already been treated using disinfectant (Virkon-S; DuPont) topically for the preceding few days but without improvement. Because viral infection was suspected, the farmer was advised to dip the teat twice daily in 10 per cent iodine.

Samples of the scabs were taken for laboratory examination. Electron microscopy revealed the presence of parapoxviral particles and Staphylococcus aureus was isolated in culture. Potentiated amoxicillin injection (Noroclav; Norbrook) was then prescribed for the cow with continuing topical iodine. Neither treatment resulted in a resolution of the clinical signs and the cow developed severe purulent mastitis in the quarter. For this reason, and as the teat sphincter was undetectable and not functional, the teat was surgically removed to allow drainage of the quarter in order to salvage the cow. Histopathology of the teat showed severe proliferative dermatitis with pronounced rete ridge formation, amphophilic cytoplasmic inclusion bodies, marked endothelial cell activation and proliferation in the papillary dermis, as well as minimal superficial purulent dermatitis associated with coccoid bacteria. Immunohistochemistry revealed extensive parapoxviral antigen in superficial keratinocytes. DNA was isolated from both