Scientists attempt to trace bird flu

HANOI, Vietnam -- International health experts tried to trace the lines of transmission of a bird flu that has killed five people and millions of chickens across Asia, as China shut trade ports along its border with hard-hit Vietnam Tuesday.\nIn Thailand, which officials claim is free of bird flu, a chicken butcher has been isolated in a hospital with symptoms similar to avian influenza. Officials said initial tests show he is sick with a bacterial lung infection.\nSix scientists from Atlanta's Centers for Disease Control and Prevention Tuesday joined the World Health Organization in Vietnam, which is leading the probe on how the flu, or the H5N1 strain, has jumped from birds to people.\nA total of 14 scientists, with expertise in epidemiology, disease surveillance and livestock and animal husbandry, will be involved in investigations, WHO spokesman Bob Dietz said in Hanoi.\nThe bird flu has ravaged poultry farms in Vietnam, South Korea and Japan. Vietnam, however, is the only country with confirmed cases of the bird flu in people. WHO has confirmed the H5N1 strain in five human cases -- all fatal.\nThe scientists will try to determine exactly how the flu is being transmitted from birds to humans. Among the puzzles they will need to solve is why the bulk of the bird infections have occurred in southern Vietnam, while all the human victims have been from the northern region around Hanoi.\nHealth officials believe patients contracted the disease through contact with the sick birds, but has not yet been confirmed.\nSo far, there has been no evidence of person-to-person transmission. But health officials have warned if the avian virus mutates to allow human transmission, it could make the disease a bigger health crisis than SARS, which killed nearly 800 people worldwide last year.\nThe spread of avian flu, along with the re-emergence of severe acute respiratory syndrome -- with three recent cases confirmed in China -- has put Asia on a region-wide health alert.\nIn a bid to monitor any potential outbreaks, a vigilant China issued an emergency notice requiring "veterinary and quarantine units at the grass-roots level" to make daily reports to higher departments.\nIf the disease is found, all poultry within two miles of the site will have to be slaughtered and all poultry within three miles will have to be vaccinated immediately, it said.\nThe southern Chinese province of Yunnan has closed all of the 40 trade ports along its 740-mile border with Vietnam and set up quarantine checkpoints to keep out the avian disease, the official Xinhua News Agency reported.\nChina's central government has already banned chicken imports from Vietnam as well as Japan and South Korea.\nMillions of chickens have died of bird flu in Thailand, a major chicken exporter, according to some farmers. But government officials attribute the deaths to fowl cholera and infectious bronchitis.\nThough Prime Minister Thaksin Shinawatra announced that a man was sick with symptoms similar to bird flu, he was quick to play down the threat, saying "so far there is no bird flu found in Thailand."\nPublic Health Minister Sudarat Keyuraphan said preliminary tests of the sick man in Nakhon Sawan province, 130 miles north of Bangkok, showed he has a bacterial lung infection. Further examinations were being done.