POSTED 17 NOVEMBER 2005
Bird flu flies on
Avian influenza -- a respiratory virus that has killed about half of the humans who have definitely caught it -- has finally caught the eye of world policymakers. Avian influenza is not just "the flu." It's an extremely contagious, fatal disease that could spiral into a global epidemic.
To
date, the H5N1 strain of flu (named for structures on the viral surface)
has caused the death of 151 million domestic birds, and an unknown number
of wild ones, either directly or through human efforts to contain the
virus. Most, perhaps all, of the known human victims caught avian flu
through close contact with infected poultry, and all lived in Southeast
Asia.
March, 2005: Women carry a basket of chickens through Hanoi, Vietnam. A top Vietnamese health official blamed public ignorance about bird flu, weak surveillance systems, and small-scale farming activities for the re-emergence of the disease. Photo: Dept. of State
All bets are off if avian influenza goes through a genetic change and becomes able to transfer directly from person to person. In 1917-18, roughly 50 million people died after a global influenza outbreak, or pandemic. That virus, like H5N1, began in birds.
Some experts say the change is almost inevitable given the history of other viruses that have "jumped" to people. Viruses, after all, are opportunists -- always swapping genes or mutating as they seek to infect new species. Since viruses can only reproduce inside cells, infection is a matter of ultimate evolutionary consequence for them.
A distinctly new strain like H5N1 can be deadly for two reasons: Influenza is highly contagious, and people have no immunity to strains they have never been exposed to.
WHO worries
The World Health Organization (WHO) started a recent conference on avian influenza with "alarming statistics," USA Today wrote on Nov. 8. "The lethal strain of avian influenza is now in 15 countries -- it has been discovered in five since July; 150 million birds have died or been culled; 124 people have been infected, and 63 of them died; and poultry losses have topped more than $10 billion."
Poultry and H5N1 influenza overlap in a big way
in Southeast Asia. Map: FAO
"It is only a matter of time before an avian flu virus, most likely H5N1, acquires the ability to be transmitted from human to human, sparking the outbreak of a human pandemic influenza," said Lee Jong-Wook, director general of WHO. "We don't know when this will happen. But we do know that it will happen," he said (see "'Matter of Time'..." in the bibliography).
Meanwhile, avian influenza spreads:
In July, China blamed a die-off in migratory birds on an extra-lethal version of avian influenza. Apparently the virus is gaining strength, at least among birds.
After dying of avian flu or being culled to prevent
infection, chicken carcasses are burned at a farm near Ho Chi Minh City,
Vietnam. Photo: FAO
Slowly, years after H5N1 first appeared among Asian poultry, the planet is gearing up to the threat of a global pandemic, and the results are not too comforting. "Pandemic influenza is going to run us ragged," said Dr. Mike Ryan, who directs the WHO's Epidemic and Pandemic Alert and Response, charged with coordinating a planetary response to H5N1, told the San Francisco Chronicle on Nov. 9.
"Is the WHO ready for a pandemic? No. We are not," said Ryan (see "Inside U.N.'s Pandemic..." in the bibliography).
Information. It's one small way to prepare for pandemic.
Megan Anderson, project assistant; Terry Devitt, editor; S.V. Medaris, designer/illustrator; David Tenenbaum, feature writer; Amy Toburen, content development executive
