Phocine distemper virus (PDV), is a paramyxovirus of the genus ''

Morbillivirus ''Morbillivirus'' is a genus of viruses in the order '' Mononegavirales'', in the family ''Paramyxoviridae''. Humans, dogs, cats, cattle, seals, and cetaceans serve as natural hosts. This genus contains 10 species, one of which is extinct. Disea ...

'' that is pathogenic for

pinniped Pinnipeds (pronounced ), commonly known as seals, are a widely range (biology), distributed and diverse clade of carnivorous, fin-footed, semiaquatic, mostly marine mammals. They comprise the extant taxon, extant families Odobenidae (whose onl ...

species, particularly seals. Clinical signs include laboured breathing, fever and nervous symptoms. PDV was first identified in 1988 as the cause of death of 18,000

harbor seal The harbor (or harbour) seal (''Phoca vitulina''), also known as the common seal, is a true seal found along temperate and Arctic marine coastlines of the Northern Hemisphere. The most widely distributed species of pinniped (walruses, eared sea ...

s (''Phoca vitulina'') and 300

grey seal The grey seal (''Halichoerus grypus'') is a large seal of the family Phocidae, which are commonly referred to as "true seals" or "earless seals". The only species classified in the genus ''Halichoerus'', it is found on both shores of the Nort ...

s (''Halichoerus grypus'') along the northern European coast. In 2002, an epizootic of PDV along the

North Sea The North Sea lies between Great Britain, Denmark, Norway, Germany, the Netherlands, Belgium, and France. A sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian Se ...

coast resulted in the deaths of 21,700 seals, estimated to be 51% of the population.

Antibodies An antibody (Ab) or immunoglobulin (Ig) is a large, Y-shaped protein belonging to the immunoglobulin superfamily which is used by the immune system to identify and neutralize antigens such as bacteria and viruses, including those that caus ...

to PDV have been found in a number of carnivorous mammal species in the Western North Atlantic, including

polar bear The polar bear (''Ursus maritimus'') is a large bear native to the Arctic and nearby areas. It is closely related to the brown bear, and the two species can Hybrid (biology), interbreed. The polar bear is the largest extant species of bear ...

s, and the Atlantic walrus. The suddenness of the emergence of PDV and related viruses in aquatic mammals has implicated environmental changes as the cause. Pollutants have been posited as contributors by interfering with the ability of animals to mount a defense against infection. Alternatively,

climate change Present-day climate change includes both global warming—the ongoing increase in Global surface temperature, global average temperature—and its wider effects on Earth's climate system. Climate variability and change, Climate change in ...

and

overfishing Overfishing is the removal of a species of fish (i.e. fishing) from a body of water at a rate greater than that the species can replenish its population naturally (i.e. the overexploitation of the fishery's existing Fish stocks, fish stock), resu ...

may have forced aquatic species that naturally harbour the viruses into new areas, exposing immunologically susceptible populations.

References

{{Taxonbar, from=Q29004632, from2=Q5040284 Morbilliviruses Pinniped diseases Animal viral diseases