Oral papillomatosis caused by Enhydra lutris papillomavirus 1 (ElPV-1) in southern sea otters (Enhydra lutris nereis) in California, USA.

The southern sea otter (Enhydra lutris nereis) is a threatened marine sentinel. During postmortem investigations of stranded sea otters from 2004 to 2013 in California, US, papillomas were detected in the oral cavity of at least seven otters via necropsy and histopathology. Next-generation sequencing of viral particles purified from a single papilloma revealed a novel papillomavirus, Enhydra lutris papillomavirus 1 (ElPV-1). The genome of ElPV-1 was obtained, representing the first fully sequenced viral genome from southern sea otters. Phylogenetic analysis of the entire L1 gene, as well as a concatenated protein identities plot of all papillomaviral genes revealed that ElPV-1 is a λ-papillomavirus, related to a raccoon papillomavirus (Procyon lotor papillomavirus type 1) and a canine oral papillomavirus. Immunohistochemical staining, using a cross-reactive bovine papillomavirus antibody, suggested that ElPV-1 is present in intranuclear inclusions and intracytoplasmic keratin granules. Virus-infected cells were scattered throughout the stratum granulosum and stratum spinosum of the gingival and buccal papillomas. Using ElPV-1-specific PCR, we confirmed viral DNA in oral papillomas from all seven stranded sea otters, with identical L1 sequences. This virus is associated with the development of oral papillomatosis in southern sea otters.

Evaluation of the pathogenic potential of cervid adenovirus in calves.

Four 3-month-old Jersey calves and three 3-month-old Holstein calves were inoculated with cervid adenovirus and monitored for clinical signs until necropsied between 10 and 42 days postinoculation. The neonatal Jersey calves had received colostrum, and the Holstein calves were colostrum deprived. Preinoculation and postinoculation serum samples were tested for antibodies to the cervid adenovirus, bovine adenovirus type 6, bovine adenovirus type 7, and goat adenovirus type 1. Virus isolation was performed on kidney, nasal secretion, and/or lung homogenates in fetal white-tailed deer lung cells. Negatively stained preparations of feces from Jersey calves were examined weekly using an electron microscope, and weekly blood samples were collected for complete blood counts. Full necropsies were performed on all calves. A complete selection of tissues was evaluated for microscopic changes, and immunohistochemistry was performed on all tissues using a polyclonal antibody to deer adenovirus. No clinical signs were observed in the calves during the study period. Following inoculation, colostrum-deprived calves developed low antibody titers to deer adenovirus, while the Jersey calves that received colostrum did not. Calves that received colostrum had high antibody titers to bovine adenovirus type 7 and goat adenovirus type 1. No consistent gross or microscopic lesions were seen. Adenovirus was not observed in negatively stained preparations of feces. Immunohistochemistry results did not demonstrate virus in all tissues examined microscopically, and virus was not isolated from lungs, nasal secretions, and kidneys.