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Genital epithelial tumors of Atlantic bottlenose dolphins (Tursiops truncatus [Tt]) and Burmeister's porpoises (Phocoena spinipinnis) were formerly shown to be associated with papillomavirus (PV) infection. Papillomaviruses are highly prevalent viruses involved in the development of various tumor types in a wide range of animals, and so-called high-risk PVs contribute to malignant progression. In marine mammals, the incidence and prevalence of PV infection, transmission pathways, and persistence of infection are largely unknown. Using virus-like particles of bottlenose dolphin PV type 1 (TtPV1) as the antigen, enzyme-linked immunosorbent assay (ELISA) studies were conducted to evaluate PV antibody prevalence in bottlenose dolphins. In total, sera obtained from 115 dolphins were examined. Fifty-one percent of captive dolphins (n=18 of 35) and 90% of free-ranging dolphins (n=72 of 80) were antibody positive. Higher ELISA reactivity was observed among males compared with females. Sexually immature dolphins appeared more likely to seroconvert with age. Besides determining their PV antibody prevalence, each animal was also assessed for the presence of orogenital tumors. Interestingly, the mean age of free-ranging dolphins with tumors (n=21) was 11.2 yr compared with 29.9 yr in captive dolphins with tumors (n=9). Results from the current study suggest PV infection in bottlenose dolphins is common, that the main route of PV transmission among them may be horizontal, and that orogenital neoplasia may develop in early life stages of certain free-ranging bottlenose dolphins.

To characterize a form of progressive keratitis that occurs commonly in otariids.One hundred and thirteen captive otariids were evaluated by ophthalmologic examination and digital photography.Forty-six females and 67 males were in the reference population, average age of 14 years. California sea lions predominated (n = 100); there were also six Steller sea lions, five brown fur seals, one Guadalupe fur seal and one northern fur seal. Three stages of progressive keratitis are described. Overall, 64.6% animals and 142 eyes from 113 animals (62.8%) were affected with one of three stages. The mildest form, Stage 1 keratitis, occurred in 78 of 226 eyes (34.5%); the intermediate Stage 2 keratitis occurred in 30 of 226 eyes (13.3%); and the most severe, Stage 3 keratitis, occurred in 34 of 226 eyes (15%). All but six animals had bilateral disease. Animals with Stage 1 keratitis were significantly younger than those in more advanced stages.'Otariid Keratitis' occurs in all populations of eared seals evaluated. A large-scale epidemiological study is ongoing to identify the risk factors that contribute to this disease. Exposure to chronic sunlight appears to be an important risk factor as shade diminishes clinical signs; animals kept out of sunlight the majority of the time have less severe clinical signs. Age may be important since exposure accumulates with aging. Progression of the disease is also associated with secondary opportunistic bacterial and fungal infections. The surface immune system may be imbalanced contributing to these infections and progression.

Papillomaviruses (PVs) have been shown as being the etiologic agents of various benign and malignant tumours in many vertebrate species. In dolphins and porpoises, a high prevalence of orogenital tumours has recently been documented with at least four distinct novel species-specific PV types detected in such lesions. Therefore, we generated the immunological reagents to establish a serological screening test to determine the prevalence of PV infection in Atlantic bottlenose dolphins [(Tursiops truncatus (Tt)]. Using the baculovirus expression system, virus-like particles (VLPs) derived from the L1 proteins of two TtPV types, TtPV1 and TtPV2, were generated. Polyclonal antibodies against TtPV VLPs were produced in rabbits and their specificity for the VLPs was confirmed. Electron microscopy and enzyme-linked immunosorbent assay (ELISA) studies revealed that the generated VLPs self-assembled into particles presenting conformational immunodominant epitopes. As such, these particles are potential antigen candidates for a TtPV vaccine. Subsequently, the VLPs served as antigens in initial ELISA tests using sera from six bottlenose dolphins to investigate PV antibody presence. Three of these sera were derived from dolphins with genital tumour history and showed positive PV ELISA reactivity, while the remaining sera from lesion-free dolphins were PV antibody-negative. The results suggest that the developed screening test may serve as a potential tool for determining PV prevalence and thus for observing transmission rates in dolphin populations as the significance of PV infection in cetaceans starts to unfold.