Characterization of a novel papillomavirus species (ZcPV1) from two California sea lions (Zalophus californianus)

A seven-year old California sea lion (Zalophus californianus) presented with focally extensive, bilaterally symmetric, proliferative axillary skin lesions and preputial lesions. A second California sea lion in the same population presented with similar proliferative lesions on the underside of the tail. Histopathology revealed epidermal hyperplasia with severe hyperkeratosis, with proliferating keratinocytes forming broad, branching pegs that extended into the dermis. Pan-papillomaviral consensus PCR was used to obtain initial E1 sequence template and the complete genome was determined using a combination of rolling circle amplification and specific-primer PCR. Analysis revealed a novel papillomavirus, Zalophus californianus papillomavirus 1 (ZcPV1), with seven open reading frames encoding five early proteins (E6, E7, E1, E2 and E4) and two late proteins (L1 and L2). Phylogenetic analysis revealed that (ZcPV1) is most closely related to Equine papillomavirus 1 (EcPV1) in the genus Zetapapillomavirus, and Canine papillomaviruses 3 and 4 (CPV3, CPV4) in the genus Chipapillomavirus. The lesions regressed without intervention over a period of several months.