There is fresh concern for seal colonies in Northern Ireland following the discovery of a deadly virus in a seal on the west coast of Ireland.

More than 15,000 seals have died in European waters over the past five months from the morbillivirus, which attacks the seal's immune system.

The discovery is the first confirmation of the infection in a seal in Ireland during the current epidemic.

Hundreds of seals died along the County Down coast during the last epidemic in 1988.

Earlier this year, common seals in Europe succumbed to a virus which killed thousands of them 14 years ago.

The virus attacks the seal's immune system

More than 1,400 dead seals were found along the coasts of Scandinavia and the Netherlands in the two months to July.

The disease, phocine distemper virus (PDV), attacked the animals' respiratory systems.

Researchers believed few seals in the affected area had acquired immunity to PDV from the 1988 epidemic.

The 1988 epidemic killed more than 18,000 European common seals, including some in UK waters.

Measles

Populations affected included those in Orkney and the Moray Firth in Scotland and the Wash, in eastern England, where about half the seals died.

The disease appeared in the UK about four months after being found in Denmark.

Grey seals - which are more abundant than common seals - were also exposed to PDV in 1988, though few died. They are thought able to carry the virus.

PDV is a morbillivirus, of the same family as measles, and related to canine distemper.

It attacks the white blood cells, which become more susceptible to chance infections.