A 3-year-old, mixed breed, male horse showed multiple nodules in different areas of the skin. Lesions occurred predominantly on the lips, cheeks, and submandibular and right inguinal regions. The nodules were characterized as mixed, fibroblastic, verrucous and occult types of sarcoid. Histologically there was proliferation of dermal fibroblasts, with or without pseudoepitheliomatous hyperplasia of the epidermis (frequently ulcerated), and formation of small isolated groups of neoplastic fibroblasts in the superficial dermis. Three tissue samples were submitted to DNA extraction and PCR amplification with generic primers for the internal region of the papillomavirus L1 gene. The amplified products from two samples were sequenced and showed 99% identity with the bovine papillomavirus (BPV) BR-UEL-4. This is the first description of BPV BR-UEL-4 infecting a horse and causing sarcoid in this species. BPV BR-UEL-4 is a putative new BPV type recently identified in skin papillomas in a Brazilian cattle herd.
horse diseases; pathology; bovine papillomavirus; BR-UEL-4; sarcoid; PCR
