Published Date: 2002-05-26 23:50:00
Subject: PRO/AH> Avian influenza - China (Hong Kong) (10)
Archive Number: 20020526.4324
AVIAN INFLUENZA - CHINA (HONG KONG) (10)
A ProMED-mail post
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International Society for Infectious Diseases
Date: Fri 24 May 2002
From: ProMED-mail <firstname.lastname@example.org>
Source: ABC News, Reuters report, Fri 24 May 2002 [edited]
Recent H5N1 avian influenza virus strains differ from 1997 outbreak strain
HONG KONG: Investigators for the Hong Kong government confirmed on Fri 24
May 2002 that the viruses in a recent outbreak of avian influenza in the
territory differed from the virus that killed 6 people in 1997. The 1997
outbreak sparked fears of a potential global epidemic, but last month the
government said there was no indication that this year's virus would
endanger humans. Hong Kong has been hit by 3 major outbreaks of avian
influenza in the past 5 years. This year, over 900 000 chickens were
killed. In 1997, and again last year, the entire chicken population of over
one million birds was slaughtered.
"None of these recent H5N1 [avian influenza virus] strains shared the same
combination of genes as those found in the 1997 virus that caused severe
disease in both man and poultry," Thomas Chan, chairman of the
investigation team and director of Agriculture, Fisheries and Conservation,
told reporters on Fri 24 May 2002. "All the viruses isolated early this
year were derived originally from the Goose GD-96 [avian influenza] virus."
The investigators said the 1997 killer H5N1 strain had not been found in
the territory since the first mass slaughter. "The investigation team
considers that the outbreak of disease on local farms was probably caused
by a small number of introductions of H5N1 [avian influenza] virus onto
farms, followed by local spread between farms," Chan said. "The spread from
farm to farm was likely to be due to the movement of people or items
associated with the poultry industry and, for some farms in very close
proximity, may have been the result of airborne spread of the virus,
possibly via contaminated dust."
Hong Kong diners prefer fresh chicken to frozen meat. Recommendations
proposed by the investigation team to reduce the chance of another
outbreak, however, included farmers avoiding any form of contact with
markets, stopping movement of materials between farms, increasing the
supply of chilled poultry, and introducing an additional market "rest day"
each month so retail markets could be disinfected.
[Byline: Carrie Lee]
[In the outbreak of avian influenza A (H5N1) virus in humans in Hong Kong
in 1997 infection was confirmed in 18 individuals, 6 of whom died.
Infections were acquired by humans directly from chickens, without the
involvement of an intermediate host. The outbreak was halted by a
territory-wide slaughter of over 1.5 million chickens at the end of
December 1997. The clinical spectrum of H5N1 virus infection ranged from
asymptomatic infection to fatal pneumonitis and multiple organ failure.
Reactive hemophagocytic syndrome was the most characteristic pathological
finding and might have contributed to the lymphopenia, liver dysfunction,
and abnormal clotting profiles that were observed among patients with
severe infection. - Mod.CP]