Canine papillomatosis is a rare viral disease in dogs characterised by numerous benign warts (papillomata) in the head area. The causative agent is canine papillomavirus. Although papillomaviruses occur in many animal species and in humans, they are strictly host-specific, so they do not pose a risk to humans or other animals. Papillomata are mainly observed in the oral cavity and are less frequently on the conjunctiva, the cornea and the eyelids. Warts are benign and usually heal without treatment within one to five months. If feed intake is severely affected by them, surgical excision might be indicated. A current study has attested a good effectiveness to the administration of azithromycin.
The equine sarcoid is one of the most common skin tumours in horses (about 2 – 12% of all horses are affected). The causative agent is bovine papillomavirus – especially type 1, more rarely type 2. The tumour cells are modified fibroblasts; the skin and subcutaneous tissue are affected. Equine sarcoids are considered semi-malignant tumours, i. e. they do not metastasise, but have a strong tendency to recur if surgical removal is incomplete. It is presumed that transmission mainly occurs through direct contact as well as flies and horseflies, but also indirectly through wound sites, saddles, blankets and cleaning utensils. The entire skin surface as well as certain blood cells are infected; moreover, the infection remains throughout life. The initial diagnosis is made at the age of 3 – 12 years.