''Phocine morbillivirus'', formerly ''phocine distemper virus'' (PDV), is a paramyxovirus of the genus '' Morbillivirus'' that is pathogenic for

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

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 se ...

s (''Phoca vitulina'') and 300

grey seal The grey seal (''Halichoerus grypus'') is found on both shores of the North Atlantic Ocean. In Latin Halichoerus grypus means "hook-nosed sea pig". It is a large seal of the family Phocidae, which are commonly referred to as "true seals" o ...

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, Norway, Denmark, Germany, the Netherlands and Belgium. An epeiric sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian ...

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

Antibodies An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of ...

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 hypercarnivorous bear whose native range lies largely within the Arctic Circle, encompassing the Arctic Ocean, its surrounding seas and surrounding land masses. It is the largest extant bear spec ...

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 In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to ...

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 stock), resulting in t ...

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