Home / Picture of the Month / December 2016

December 2016

Seal: Poxviral dermatitis



18kg male stranded grey seal pup submitted to a Scottish rehabilitation centre


Seal poxviral dermatitis


Moderate, multifocal, proliferative and ulcerative dermatitis on the palmar aspect of the anterior flipper.

Histologically, the epidermis was markedly hyperplastic with extensive ballooning degeneration and eosinophilic, variably sized intracellular inclusion bodies


Proliferative lesions of the skin and oral mucosa of grey seals have been attributed to a novel group of marine poxviruses, bearing much similarity to terrestrial parapoxviruses such as those seen in contagious pustular dermatitis (orf) of sheep and goats and bovine papular stomatitis.

In grey seals, the lesions arise in young animals and are frequently exacerbated by stress as they often appear a few weeks after entering a rehabilitation centre. Infection manifests as plaque-like to nodular areas of hyperkeratosis and parakeratosis with ballooning degeneration of keratinocytes with eosinophilic intracytoplasmic, and occasionally intranuclear, viral inclusion bodies. The clinical significance is not fully known but this condition is thought to cause a highly infectious, self-limiting disease which can leave areas of scar tissue or alopecia following resolution.

Picture and authored by: Dr Johanna Baily, Dipl ECVP, Institute of Aquaculture, University of Stirling, UK