Chinese authorities have slaughtered 170,000 chickens as a fast-mutating avian flu virus spreads.  A scientist leading research into the bird flu outbreak says the virus could mutate into a form infectious to humans.

Officials have sought to calm fears by saying recent tests of samples from sick chickens have not found the H5N1-97 strain of the virus that infected humans in 1997.  "It will need one little chance ... and this could give rise to a serious virus," Dr. Ken Shortridge, a microbiologist at the University of Hong Kong who is heading an investigation into the flu outbreak.

Mainland China, the source of 80 percent of Hong Kong's live poultry, has long been thought to be an incubator of flu viruses, the last two of three flu pandemics that swept the world originated there. In 1997, a strain of flu virus crossed from chickens to humans, killing six people.

Since 1997, periodic outbreaks of bird flu here have led to massive culling at the farms and open-air markets that supply the 100,000 chickens to Hong Kong residents eat each day, to pre-empt the emergence of another crossover virus.

Last May, a similar avian virus infected thousands of chickens, forcing the government to destroy 1.37 million birds. That outbreak did not affect humans.  Some older residents shopping at a market seemed unperturbed by yet another spate of bird flu, despite the potential of a dangerous mutant virus.

This time, officials have resisted a territory-wide slaughter.  Chickens at several markets and three farms _ a total of about 170,000 _ have been killed, mainly gassed to death by carbon dioxide in air-tight plastic trash cans.  So far, close to 30 of Hong Kong's 144 poultry farms have been shut down or quarantined. Poultry markets were ordered to close for a thorough cleaning, and imports from China were suspended for two days. The exact number of chickens killed by the virus has not been reported, though earlier official reports said more than 30,000 birds had died.

An avian flu sweeping Hong Kong poultry farms is mutating fast and officials are fighting to stop it from evolving into a strain that crossed to humans and killed six people in 1997, a top scientist said Wednesday.

"At the moment, it does not present an immediate threat (to humans). But that threat is there if it does happen to go to the right type of reassortment (mutation)," Ken Shortridge, who is studying the virus, said on Hong Kong RTHK radio.  "It will need one little chance ... and this could give rise to a serious virus." 

Earlier, Shortridge told the daily South China Morning Post that the bird flu outbreak came from the same family of viruses that mutated into the deadly human strain in 1997.

That outbreak forced authorities to slaughter all domestic fowl, more than a million birds. The latest scare hit as Hong Kong prepares for Chinese New Year next week, when fresh chicken is a main dish.  Officials were criticized in 1997 for their slow response to the outbreak, just after Britain returned the territory of seven million people to China, and the government of Chief Executive Tung Chee-hwa was deeply embarrassed.  This time, Hong Kong health officials have tried to move quickly to stop the virus before it mutates into a rogue strain that threatens humans.

BIRDS SLAUGHTERED, IMPORTS HALTED

Some 169,000 birds from two farms and four markets have been killed since the weekend and 24 more poultry farms were shut on Tuesday.  Imports of live chickens, mostly from mainland China, were halted Wednesday and Thursday and chicken sales will be halted Friday so "all poultry stalls and fresh provision shops can be thoroughly cleansed and disinfected," a government statement said.

About 20 percent of some 100,000 live chickens sold daily are raised in the territory. The remainder come largely from mainland China.  Shortridge said the danger came from the speed with which the virus was mutating in Hong Kong's aquatic bird population. It could become a risk to humans but so far this was not the case.

The government has said the virus had not been identified as yet, but Shortridge said it was from the H5N1 goose family from which the 1997 strain that killed humans emerged.  It is still the Guangdong goose family (of H5N1) but it is moving away from the Guangdong virus of 1996," the parent strain of the 1997 flu, he said.  "The way the virus is behaving now, we are seeing it undergo many, many of what we call reassortment, swapping genes with many other viruses quickly," he told RTHK on radio.

The southern China region is known as an incubator for flu viruses and the latest outbreak comes at the height of the flu season. Hong Kong had to order a mass cull of 1.2 million birds last May after another virus scare. Agriculture officials in neighboring Guangdong province and Shenzhen city in southern China said they had seen no sign of the bird flu outbreak.

They were seized as they tried to enter Lima's San Pedro prison.  The plucked chickens were found to contain a total of 10 kilos of cocaine.  Police believe the gang was working in partnership with a guard at the prison.

Terra Populares reports that police suspect the same gang has smuggled drink, cigarettes and guns into the prison in the past.