BEIJING — Alarmed by the continuing spread of a deadly flu virus transmitted from birds to humans, Hong Kong health officials prepared today to slaughter the territory's entire population of farm-raised chickens and other poultry in markets and farms.
The extreme move, which follows a ban on chicken imports from China, was announced Sunday by Hong Kong Director of Health Margaret Chan after doctors confirmed at least 12 cases of the H5N1 virus, four of which were fatal. Nine other people, ranging widely in age, are suspected of having the virus, a particularly virulent type previously believed to infect only birds.
Health and agriculture officials said that more than 1,000 workers wearing masks and protective clothing will fan across the territory beginning this morning to gather an estimated 1.3 million chickens from 1,000 markets and 160 farms. The birds will be captured in sealed containers, asphyxiated, placed in plastic bags and buried in landfills.
"From tomorrow morning, we will start destroying all the chickens in Hong Kong Island, Kowloon and the New Territories," Secretary for Economic Services Stephen Ip told a news conference Sunday. Ip said the workers will also gather and kill ducks, geese, pigeons and quail housed near the chickens, in an operation that he said will be completed in 24 hours.
After the first case of the so-called bird flu or avian flu was confirmed this summer, international health authorities descended on Hong Kong seeking to solve the mystery of the new flu outbreak and come up with a vaccine before it spread outside the vicinity. So far, they say, they still have no evidence of significant airborne human-to-human transmission from ordinary contact, although one health worker apparently contracted a mild case of the flu from a patient after contact with bodily fluids.
Last week, the territory's authorities banned imports of chicken and other poultry from neighboring Guangdong province on the mainland, where Hong Kong got more than 70% of its live and fresh poultry. The precautionary move was taken because some officials believe that the virus outbreak, which first hit three Hong Kong New Territories chicken farms in March, originated in China.
Mainland Chinese officials, although cooperating with World Health Organization investigators, have denied any outbreaks among their poultry population and said that, so far, they have no human cases.
A team of epidemiologists from the U.S. Centers for Disease Control and Prevention in Atlanta has been in Hong Kong for three weeks attempting to investigate the virus. However, the government scientists said their efforts have been hampered by its extreme virulence.
Some experts have estimated that the earliest date that a vaccine can be produced is mid-1998. However, doctors say that the virus has proved to be sensitive to the drug amantadine, which has been given to health workers and family members of infected people in Hong Kong as a preventive measure.
The main fear is that the bird flu could be the beginning stage of a worldwide flu pandemic like those that have occurred at least three times this century. The last pandemic, in 1968, had its origins in Hong Kong, and many epidemiologists feel that China is the main world incubator of new flu types.
The latest confirmed fatality from H5N1 Type A influenza was a 60-year-old woman who died Tuesday. The first recorded death was a 3-year-old boy who died in May but whose case was not confirmed as H5N1 until August. The other fatalities were a 13-year-old girl who died last week and a 54-year-old man who died Dec. 5.
Hong Kong's decision to kill all chickens came after health authorities, who have been conducting regular testing at farms and markets, on Sunday declared a chicken farm and part of Hong Kong's largest poultry market infected areas.
A government statement said blood samples taken from chickens at the Yuen Long farm near the border with China tested positive for the H5N1 virus.
It also said that a section of the Cheung Sha Wan wholesale poultry market, the target of a massive cleanup operation earlier this month, was closed because veterinary officers found a large number of dead chickens there.
The market used to sell more than a third of the 75,000 chickens imported into Hong Kong daily from China.
Some vendors were already killing their chickens Sunday and putting them in plastic bags for collection by government workers, local television reported.
On Saturday, health officials said blood tests have shown that some humans apparently can develop immunity to the virus. Doctors have discovered antibodies to the virus in the blood of nine people tested who never became severely sick. The presence of antibodies means a person has been exposed to the virus and has developed resistance.