Novel canine papillomavirus type 18 found in pigmented plaques.

A variety of neoplasias of the skin and mucous membranes in humans and animals can be ascribed to papillomavirus infections. Some of these papillomavirus induced neoplasias can undergo malignant transformation, while most remain benign. Papillomavirus infections are often even asymptomatic. Therefore the understanding of these viruses is important for appropriate prevention, diagnostic and therapeutic approaches. The entire genomic sequence of a new canine papillomavirus was determined from DNA detected in pigmented plaques in a pug. The novel canine papillomavirus type 18 (CPV18) falls into the genus Chipapillomavirus whose members have all been isolated form dogs with pigmented plaques, some of them also with squamous cell carcinomas. A small partial sequence of a 2009 isolate from a dog in California is identical with CPV18. Papillomaviruses (PVs) are non-enveloped, double-stranded DNA viruses with a circular genome of about 8.000 base pairs (bp). They are generally host species-specific with some exceptions. Numerous of the known PVs are associated with benign and malignant neoplasias of the skin and mucous membranes in humans and animals, but there is evidence, that asymptomatic infections are more common [1,9,14]. More than 200 human and 140 animal PVs have been characterized, illustrating broad genetic diversity (http://pave.niaid.nih.gov/) [2,6,9]. The identification and study of new animal PVs are important because new PVs are potential pathogens in veterinary medicine, some animal PVs may serve as models for human disease and tools for basic biology, and the analysis of animal PVs helps provide insights into PV evolution. Canine PVs (CPVs) have been found associated with classical exophytic papillomas such as the common canine oral papillomatosis, with endophytic papillomas, with pigmented plaques and in rare