Cutaneous plaques associated with a putative novel papillomavirus type in a horse.

Unlike more typical equine cutaneous warts which generally appear as pedunculated and filiform masses, the lesions in this horse appeared as raised plaques. With the exception of aural plaques that are confined to the ears, localised clusters of papillomaviral plaques have not been previously described in horses. The lesions contained subtle histological evidence of papillomavirus infection and careful examination is required to differentiate these plaques from pre-neoplastic lesions. The plaques contained a putative novel papillomavirus type. These results increase the spectrum of papillomavirus-induced skin disease in horses.