The most common canine papillomavirus is COPV (recently reclassified as CPV1). Most incidences of COPV infection happens in young dogs. Canine oral papillomas have an incubation period of 4–8 weeks. The oral warts last about 4- 6 weeks, and typically completely regress after a further 4 weeks. The benign lesions rarely cause clinical problems unless their location leads to respiratory obstruction or dysphagia. Where removal is required, it is usually carried out by excision, cryosurgery or electrosurgery. Outbreaks of papillomatosis occur in dog colonies, affecting up to 25% of animals. It was reported in 1898 an outbreak of canine oral papillomatosis affecting 85% of a group of foxhounds. In rare instances, successive crops of non-regressing warts, refractory to treatment by surgery, autogenous vaccination or other therapies,spread throughout the buccal mucosa, tongue and palate, necessitating euthanasia. Being non-enveloped, canine papillomavirus is fairly stable in the environment and ethanol is not effective.