The virus has been found in wild swans in Sicily, and other cases are suspected elsewhere in Italy, the country's health minister says.

A specialist UK laboratory has identified the virus in dead swans found in northern Greece and Bulgaria.

The H5N1 strain of bird flu has killed at least 80 people since early 2003, mostly in South-East Asia.

Bird flu appears more likely to wing its away around the globe by plane than by migrating birds. Scientists have been unable to link the spread of the virus to migratory patterns, suggesting that the thousands of wild birds that have died, primarily waterfowl and shore birds, are not primary transmitters of bird flu.

If that holds true, it would suggest that shipments of domestic chickens, ducks and other poultry represents a far greater threat than does the movement of wild birds on the wing.

It also would underscore the need to pursue the virus in poultry farms and markets rather than in wild populations of birds if a possible pandemic is to be checked, U.S. and European experts said.

The H5N1 strain has infected millions of poultry throughout Asia and parts of Europe since 2003. The virus also has killed at least 71 people, many of whom had close contact with poultry.

"There is more and more evidence building up that wild migratory birds do play some role in spreading the virus, but personally I believe -- and others agree -- that it's not a major role," said Ward Hagemeijer, a wild bird ecologist with Wetlands International, a conservation group in Wageningen, Netherlands. "If we would assume based on this evidence that wild birds would be a major carrier of the disease we would expect a more dramatic outbreak of the disease all over the world."

Beijing, 25 November: Commenting on a recent Internet report that alleges that "a Japanese virus expert has claimed that hundreds of Chinese people have died from avian influenza," Mao Qunan, spokesman for China's Ministry of Health, said to Xinhua during an interview that the allegation was strictly a rumour.

Mao Qunan said: "The Ministry of Health and the WHO have confirmed that none of the experts whom WHO commissioned to investigate avian influenza in Hunan was a Japanese virus expert. The report that says that this expert has claimed that hundreds of Chinese have died because of avian influenza infection is untrue."

Tashiro has now told New Scientist that the figures were examples of the "unauthorised information" circulating in China, where he was recently helping investigate the outbreak in Hunan for the WHO.

Earlier reports suggested that Tashiro believed 300 to be the true death toll from bird flu in China. "I do not know whether the numbers were based on any evidence," he says.

But the message is that "we do not know how many cases actually occurred in China", due to poor disease surveillance. "If surveillance is done more extensively, more cases may be detected." He says the international community should assist China with monitoring. He describes the situation as an "iceberg phenomenon" -- with most cases unreported.

The test result confirms that the lethal variant of the virus has arrived on the European continent.

"The results are that it is H5N1 but further laboratory results are required in order to confirm the origin of the virus," said a spokesman for the UK agriculture ministry.

Romanian officials have said further drastic measures will be needed to contain the outbreak.

Domestic poultry has already been culled in the affected area, and a 3km quarantine zone has been set up around it.

Results showing whether this case, or the earlier confirmed outbreak, is the lethal H5N1 strain found in Turkey are expected in the coming days.

The World Health Organization says there is a high probability that the first birds did carry that strain.

The news comes as EU veterinary officers hold an emergency meeting to discuss measures to contain bird flu.

In Turkey and Romania, the sites of bird flu infection have been close to areas favoured by migratory birds.

Working on virus samples from the remains of victims of the 1918 pandemic, the researchers were able to piece together the entire genetic sequence of the virus.

They found the virus contained elements that were new to humans of the time - making it highly virulent.

And analysis of the final three pieces of the virus' genetic code has revealed mutations that have striking similarities to those found in flu viruses found only in birds, such as the H5N1 strain currently found in south east Asia.

What exactly is bird flu?
Bird flu is a viral infection carried by wild birds. It has now spread to domesticated birds and has killed over 100 million of them. Now the bird flu virus has shown it can easily mutate and in some instances make a direct jump from birds to people. Thee have been at least 100 human cases mainly in the far east with the most case occurring in Vietnam.

When did the first human case occur?
1997

Why is bird flu different from regular flu?
Bird flu is genetically different and much more lethal with over half the victims dying. The most deadly type of bird flu virus is H5N1 and it is very similar genetically to the 1918 Spanish Flu that killed 59 million worldwide.

Dr Nabarro stressed he would be working hard to control bird flu through contact with farming communities and markets where birds are sold and looking at the migration of wild birds.

He said the number of deaths from any future influenza pandemic would depend on where it started, how quickly it was discovered and the kind of response they got from governments.

"The range of deaths could be anything between 5m and 150m," said Dr Nabarro.

"I believe that the work we're doing over the next few months will make the difference between, for example, whether the next pandemic leads us in the direction of 150 or in the direction of five. "So our effectiveness will be directly measured in lives saved and the consequences for the world."

The scare was triggered a few weeks ago when several research groups visiting Vietnam filed preliminary reports that many people with mild cases of influenza - and those in contact with them - were testing positive for the deadly avian flu strain H5N1. This suggested that there was widespread human-to-human transmission of the virus.

Subsequent tests have so far failed to confirm this, and WHO spokesman Dick Thompson is keen to play down the incident. "It was just unpublished information provided to us in preliminary form that spurred an investigation," he says. "We thought about upgrading the alert. We looked at it fast and strongly, and based on that decided not to upgrade."

A farm worker in South Sulawesi has tested positive for the H5N1 strain of the virus, although he has shown no outward symptoms of the disease.

In the past 18 months at least 53 people across Asia are known to have died of bird flu - all of them in Cambodia, Vietnam or Thailand.