European epidemic killed 18,000 seals - scientists
Date: 03-Oct-02
Country: SWEDEN
The first victims of the phocine distemper virus (PDV), which weakens the seals' immune systems and causes pneumonia-like symptoms, were found in May on the Danish island of Anholt in the Kattegat Strait between Sweden and Denmark.
The epizootic - an epidemic among animals - resembled a 1988 PDV outbreak which also killed some 18,000 seals. Like 14 years ago, the virus spread from Kattegat to the German and Dutch coasts as well as south-eastern England.
"Now the population has declined so much that we will probably not see an epizootic next year..." said Magnus Lejhall, marine biologist at the Tjarno laboratorium in southern Sweden.
He said scientists, who have taken samples from more than 2,000 seals killed by the virus over the summer, were now collecting blood samples of live seals to study their immune system.
Scientists are also trying to find out why the virus had lain dormant for the past 14 years and what caused the outbreak.
Scientists are testing two hypotheses, the first being that minks in the region - Denmark is the world's biggest mink producer - carried the virus.
The other theory is that grey seals, eastern cousins of harbour seals, may have transmitted PDV to the harbour seal population. Grey seals catch the virus but rarely die of it.
The PDV outbreak is likely to be the largest epizootic ever reported among sea mammals. Biologists also plan to study whether pollutants and genetics affect the resistance of seals.
