Government workers destroyed poultry at a Hong Kong farm Tuesday after dead chickens -- including some vaccinated birds -- tested positive for bird flu. (Photo: AFP)DECEMBER 14, 2008
By JONATHAN CHENG
The Wall Street Journal
HONG KONG -- A lethal strain of avian influenza has resurfaced in Hong Kong, India, Indonesia and Cambodia, raising the threat to humans as the traditional winter flu season approaches.
Authorities in India's northeastern Assam state said they will cull 200,000 chickens after a fresh outbreak there of the bird flu strain known as H5N1. Hong Kong is coping with the first appearance of H5N1 on its poultry farms in more than five years. On Tuesday, it quarantined a chicken farm and culled 80,000 birds.
In Indonesia, the World Health Organization confirmed two new cases of human bird flu on Tuesday, while in Cambodia, a 19-year-old has been confirmed with the virus, the country's first human case in more than 18 months, the World Health Organization and Cambodian government said.
Bird flu remains a threat primarily to poultry, not humans, among whom it is poorly transmitted. Since a peak in 2006, the number of confirmed human cases of H5N1 bird flu reported to the WHO has tapered off, with 38 cases this year -- the majority in Indonesia -- leading to 29 deaths. That's a tiny fraction of the number of deaths each year from regular influenza.
A threat remains in the strain's potential to mutate into a truly human disease that health authorities warn could kill tens of millions.
Hong Kong's chicken deaths included vaccinated birds, suggesting that the vaccine used for the past six years may have lost its effectiveness. Hong Kong officials say smugglers of infected fertilized eggs from mainland China may have penetrated the city's defenses.
Yi Guan, a professor of microbiology at Hong Kong University, notes the current strain of H5N1 virus has persisted since 1996, making it the longest-lasting potential human-influenza virus compared with the two-dozen human influenza outbreaks over the past century. He added the recent spate of cases across the region may not be completely isolated and would likely get worse as winter sets in, when the risks of influenza tend to peak.
Several human vaccines for bird flu, including one made by Sanofi-Aventis SA and another by GlaxoSmithKline PLC, have been developed, but their effectiveness is still untested. Developing and producing a more-precise vaccine that targets a particular bird-flu strain more lethal to humans could take more than six months.
Write to Jonathan Cheng at jonathan.cheng@wsj.com
Authorities in India's northeastern Assam state said they will cull 200,000 chickens after a fresh outbreak there of the bird flu strain known as H5N1. Hong Kong is coping with the first appearance of H5N1 on its poultry farms in more than five years. On Tuesday, it quarantined a chicken farm and culled 80,000 birds.
In Indonesia, the World Health Organization confirmed two new cases of human bird flu on Tuesday, while in Cambodia, a 19-year-old has been confirmed with the virus, the country's first human case in more than 18 months, the World Health Organization and Cambodian government said.
Bird flu remains a threat primarily to poultry, not humans, among whom it is poorly transmitted. Since a peak in 2006, the number of confirmed human cases of H5N1 bird flu reported to the WHO has tapered off, with 38 cases this year -- the majority in Indonesia -- leading to 29 deaths. That's a tiny fraction of the number of deaths each year from regular influenza.
A threat remains in the strain's potential to mutate into a truly human disease that health authorities warn could kill tens of millions.
Hong Kong's chicken deaths included vaccinated birds, suggesting that the vaccine used for the past six years may have lost its effectiveness. Hong Kong officials say smugglers of infected fertilized eggs from mainland China may have penetrated the city's defenses.
Yi Guan, a professor of microbiology at Hong Kong University, notes the current strain of H5N1 virus has persisted since 1996, making it the longest-lasting potential human-influenza virus compared with the two-dozen human influenza outbreaks over the past century. He added the recent spate of cases across the region may not be completely isolated and would likely get worse as winter sets in, when the risks of influenza tend to peak.
Several human vaccines for bird flu, including one made by Sanofi-Aventis SA and another by GlaxoSmithKline PLC, have been developed, but their effectiveness is still untested. Developing and producing a more-precise vaccine that targets a particular bird-flu strain more lethal to humans could take more than six months.
Write to Jonathan Cheng at jonathan.cheng@wsj.com
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