Don't blame wild birds for H5N1 spread: expert

Wed Jan 23, 2008 12:29pm GMT BANGKOK (Reuters) -

There is no solid evidence that wild birds are to blame for the apparent spread of the H5N1 virus from Asia to parts of Europe, Africa and the Middle East, an animal disease expert said on Wednesday.

There was also no proof that wild birds were a reservoir for the H5N1 virus, Scott Newman, international wildlife coordinator for avian influenza at the U.N.'s Food and Agriculture Organization, said at a bird flu conference in Bangkok.

After H5N1 was found in 2005 in a huge lake in central China where it killed over 10,000 wild birds, it turned up in parts of Europe, Africa and the Middle East, leading some experts to believe migratory birds may be to blame.

But Newman said there was no good reason for thinking so.

"We know that some wild birds have probably moved short distances carrying viruses and then they died, but we have not been able to identify carriage of H5N1 across large scale spatial distances and then resulting in spread to other birds and mortality in poultry flocks," Newman told Reuters.

He said fecal tests on some 350,000 healthy birds worldwide had to date only yielded "a few" positive H5N1 results.

Furthermore, in instances and places where wild birds were found with the disease, there were no concurrent outbreaks of the virus in poultry.

"So we don't have at this point in time a wildlife reservoir for H5N1 ... so they can't be a main spreader of the disease," Newman said.

He stressed the need to focus attention on the poultry trade, and particularly smuggling, adding that these factors may instead be spreading and sustaining the deadly disease.

"We recognize that poultry production, trade, both legal and illegal, and other bio-security issues are probably more important as far as being a mechanism that promotes the sustaining and spread of H5N1," he said.

Experts have warned for years that a flu pandemic was long overdue and they stressed at the three-day Bangkok conference that the H5N1 bird flu virus remained a key candidate.

The virus has killed millions of chickens and ducks and despite the slaughter of millions more and vaccination campaigns, it remains entrenched in many poultry populations.

Although the virus has infected only 351 people around the world since 2003, it has killed 219 of them, according to the World Health Organization.

(Editing by Darren Schuettler)

source: Reuters