A deadly epidemic that may threaten the entire seal population in Irish waters has prompted calls from the Irish Seal Sanctuary for more vigilant public behaviour.
"We now regard every seal as potentially infected," said Mr Brendan Price, spokesman for the Irish Seal Sanctuary.
"If anyone comes across a seal washed up on the shore, it is there for a reason," he added. "If it is lethargic and appears sick, just leave it and report it to the authorities."
It is estimated that 330 seals died of phocine distemper virus in the north Irish Sea in the last northern European epidemic in 1988. Mr Price fears a similar number could be affected this time. In total, 18,000 seals, representing half the northern European population, were killed in 1988.
There is no explanation for the reappearance of the virus. To date, over 2,000 seals have died around the Danish, Dutch, Swedish and British coasts since its re-emergence in May.
While there are no proven cases of transmission of the virus to humans, there is a "low but quantifiable risk to dogs", said Dr James Barnett, a vet and volunteer with the British Divers Marine Life Rescue.
"There are a couple of confirmed cases in the Arctic Circle, where the disease has been passed on to dogs," he said. "Although most dogs are vaccinated against it, owners should be more vigilant at this time, if living on the coast".
The virus, which had its first confirmed case in Britain this week, could be responsible for the death of a seal found in Salthill, Galway last Wednesday. A post-mortem is now being carried out to determine the cause of death. Verification will not be available for up to 14 days.
The Irish Seal Sanctuary spokesman also advised against disturbing a herd of seals, in the open water, which "could distribute them and the disease further".
The virus affects the immune system of seals and leaves them susceptible to other infections, such as pneumonia. It spreads between animals in the same way a cold spreads to humans - by inhalation, or through contact with other secretions that carry the virus.Very few seals are immune to the virus, while only 5-20 per cent of them are expected to have acquired immunity from the last epidemic.