The seal is a sociable animal. But the creature's friendly habits are now costing it its life. Experts say that viruses have little trouble spreading fast among seal populations.

Indeed, in 1988, the Phocine Distemper Virus (PDV) cost the lives of 18,000 seals on Germany’s North Sea cost, effectively wiping out some 60 per cent of the area’s seal population.

Repetition of a nightmare

There are now fresh signs that the environmental nightmare is seeing an unwelcome revival.

The first dead seals with the lethal virus were discovered two months ago in Kattegat, just off the Danish island Anholt.

Since then 2000 animals have fallen victim to the deadly disease off the Scandinavian coast, and the first five infected seals were washed up on German shores this week.

Slow and painful death

The present crisis is almost a repitition of the virus-outbreak scenario, 14 years ago.

The 1988 epidemic, the first to have been reported since researchers counted some 37,000 seals living in the North Sea’s mud flats back in 1900, was sparked by arctic seals. They are believed to have been suffering from Russian and Scandinavian overfishing and looking for nutrition way beyond the boundaries of their natural habitat.

The PDV virus befalls lungs and respiratory organs and bacterial infections bacteria follow. As parasites spread easily to other body organs, the seal dies a slow, and painful death.

While arctic seals are able to live with the PDV virus, the North Sea seal’s population are defenceless against this relatively new epidemic, as they lack the necesary antibodies.

In addition, weakened by a steady increase in marine pollution, these animals now stand little chance of survival.

Weakened by pollution

The origins of PDV and the reasons why it has befallen Anholt for a second time are a mystery.

Animal lovers and activists are becoming increasingly divided over the virus. Some say it is natural selection - the fishing industry estimates the size of the seal population has grown up to more than 20,000 animals.

Others say it may have been brought in by a single animal from waters further afield - similar to the source of the virus back in 1998.

But what scientists have found, however, is a close link between the virus, and high levels of pollution.

Recent thyroid examinations on dead North Sea seals show severe thyroid damage, coinciding with reports of seals from areas off the North German coast containing 17 times the amount of immune system damaging PCBs than their counterparts in Iceland.

According to seal expert Günter Heidemann from Kiel, "the virus alone was not responsible for the seal epidemic in 1988". "It was also the immunodeficiency, resulting from high pollution levels", he told the German weekly Frankfurter Allgemeine am Sonntag.

No remedies

Earlier this week, Jürgen Trittin, Germany’s Environment Minister, said he reckoned with an expansion of the virus in North Sea waters.

A serum, which sparked fresh hopes of treatment in Scandinavia, has proved little help against the contagious disease: Reaching 20 000 seals in open waters with a serum which can only be injected into the animal’s muscle tissue is a tough task.

Local authorities on Germany’s North Sea coast are already bracing themselves for a large-scale epidemic.

But given the lethality of the virus, local crisis management will most likely be reduced to one measure: the removal of carcasses.