Hong Kong Confirms H5N1 Bird Flu At Chicken Farm

`It has been confirmed as H5N1,` said a government spokeswoman.

Hong Kong on Thursday confirmed an outbreak of the highly pathogenic H5N1 bird flu on a chicken farm, while pledging to investigate claims that smuggled eggs from mainland China might be the cause.

The H5N1 outbreak near the border with the mainland, which led to the culling of tens of thousands of chickens, was the city's first farm outbreak in five years despite mass vaccination of the birds, raising fears that the virus may have mutated.

"It has been confirmed as H5N1," said a government spokeswoman citing an Assistant Director of the Agriculture, Fisheries and Conservation Department, Thomas Sit.

Since the H5N1 virus resurfaced in Asia in 2003, it has killed more than 200 people in a dozen countries, according to the World Health Organisation. Experts fear the constantly mutating H5N1 virus could change into a form easily transmitted from person to person and potentially kill millions worldwide.

Chicken traders who have been hit by a three-week import ban on live chickens have claimed fertilised eggs smuggled from mainland China in contravention of Hong Kong's strict bird flu control measures may be spreading the disease.

Hong Kong's health chief said inspections of local farms had revealed nothing suspicious, but pledged to investigate.

"If some industry people are doing this it would be extremely inappropriate and irresponsible. If people have evidence I hope they can provide these details so we can follow up," said Health Secretary York Chow.

"We aren't ruling out any possibilities, though the H5N1 source is not likely to have come from inside the farm but to have come from outside," said Chow.

"But what caused the infection, be it chicks or eggs ... or workers, we still have to check up on this."

Hong Kong now has farms, including the one affected, which are allowed to import fertilised eggs from China to breed their own chicks. But some birdflu experts played down the possibility of live chicken embryos in such eggs being a potential undetected mode of transmission.

"It is very unlikely that the eggs would be infected with H5N1. Chickens that contract H5N1 would almost certainly stop laying eggs," said Leo Poon, a microbiologist from the University of Hong Kong.

Poon did not however rule out the possibility that the surfaces of eggs may be tainted with faeces containing the virus due to environmental contamination.

Hong Kong, a former British colony which returned to Chinese rule in 1997, has so far culled over 75,000 chickens at the affected farm and a wholesale market since Tuesday, with further precautionary culling in the vicinity of the stricken farm.

But Chow said an extensive series of lab tests had only shown up the H5 avian flu in one farm so far, suggesting the outbreak had been effectively contained for now.