Parapoxvirus Infection in Harbor Seals (Phoca vitulina) from the German North Sea

Abstract

In the summer of 2000, proliferative lesions of the skin and oral mucosa were observed in 26 young harbor seals (Phoca vitulina) from a rehabilitation center in Schleswig-Holstein, Germany. Verrucose, roundish nodules, approximately 1-2 cm in diameter, were presented in the oral cavity, especially on the tongue. Some animals developed similarly sized spherical dermal elevations with ulceration on flippers, chest, neck, and perineum. Necropsy of one animal showed multifocal, verrucose nodules in the oral cavity and a mild tonsillitis. Histologically, the nodules were characterized by ballooning degeneration of the outer parts of the spiny layer and stratum granulosum, with large eosinophilic cytoplasmic inclusions and a perivascular to interstitial lymphohistiocytic infiltration accompanied by fibroblastic proliferation and neovascularization. Negative staining of mucosal tissue homogenates demonstrated parapoxvirus-like particles. The presence of parapoxvirus was confirmed by polymerase chain reaction, using primers specific for parapoxvirus of ungulates. By in situ hybridization, using a parapox-specific, digoxigenin-labeled DNA probe, abundant parapoxvirus DNA-positive epithelial cells were detected in the stratum granulosum and the outer parts of the spiny layer. There was no parapoxvirus-positive signal in the adjacent submucosa. Although DNA analysis revealed that the causative agent can clearly be distinct from terrestrial parapoxviruses, lesions resembled parapoxvirus infections in other terrestrial species, and the pattern of virus DNA distribution indicated a direct effect of the virus on keratinocytes. In contrast, changes in the corium may be considered an indirect response mediated by the virus or the immune system.

Causes of Mortality in Northern Fur Seals (Callorhinus Ursinus), St. Paul Island, Pribilof Islands, Alaska, 1986–2006

“…13). Many of the neoplastic cells had large irregular eosinophilic cytoplasmic inclusion bodies and with electron microscopy discrete viral particles compatible with a parapoxvirus (Muller et al, 2003;Nollens et al, 2006). This tumor was classified as a well-differentiated squamous cell papilloma associated with a parapoxvirus.…”

Prevalence of Epidermal Conditions in California Coastal Bottlenose Dolphins (Tursiops truncatus) in Monterey Bay

“…Poxvirus has been well documented in seals and sea lions (Wilson et al 1969;Wilson et al 1972;Becher et al 2002;Muller et al 2003), which occupy the same coastal areas as bottlenose dolphins in California, and is known to occur in cetaceans (Flom and Hoek 1979;Geraci et al 1979;Van Bressem et al 1993Brownell et al 2007). The coastal environment in California, and in Monterey Bay in particular, is of concern because of high contaminant loads and general levels of pollutants (Hartwell 2008).…”

Orf: an update on current research and future perspectives

“…A number of other viruses have been identified as tentative species of parapoxvirus, but are not recognized as official members of the genus; these include seal poxvirus [13], chamois contagious ecthyma and Auzdyk disease virus (both of which affect camels) [7,14]. Parapoxviruses affecting sea lions [15], harbor seals (Phoca vitulina) in the German North Sea [16], gray seals (Halichoerus grypus) and Weddell seals (Leptonychotes weddellii) in Antarctica [17] have also been reported. Studies have shown that the Weddell seal virus is genetically related to parapoxvirus of gray seal (Halichoerus grypus) and harbor seal (Phoca vitulina) under the tentative seal parapoxvirus species [17].…”