Web Zap*Germs Archive

March 15, 2006

Bird Flu in a "Smoldering Phase" - Poultry Farms the Problem

So says Dr. Kennedy Shortridge in an article in the current SEED Magazine."I have no idea if H5N1 will cause a pandemic," continues Dr. Shortridge, an emeritus professor of microbiology at Hong Kong University who has spent three decades studying influenza. "We can't be certain at all." Shortridge led the campaign against H5N1 in Hong Kong in 1997, after it killed six people.

Shortridge believes H5N1 is presently in a "smoldering phase" of evolution similar to that undergone by the 1918 [flu] virus before it eventually broke out. He thinks the process could last another decade while the virus tests human defenses.

Pandemic viruses, says Shortridge, "have hierarchical capabilities. That is: the ability to enter the human host, escape the immune system and move on to produce new variants of itself." He suspects H5N1 may not possess this intrinsic ability, a prognosis that was echoed by Dr. Peter Palese, head of Mount Sinai School of Medicine's Microbiology faculty, who told The New York Times, "The virus has been around for more than a dozen years, but it hasn't jumped into the human population. I don't think it has the capability."

The global preparedness effort, beyond developing new super-drugs or vaccines as vital last lines of defense, says Shortridge, should be highlighting the need to prevent these outbreaks from occurring at all. He insists the way to truly beat viruses like H5N1 is to eradicate the conditions that foster a virus' rise from benign to lethal. In the current instance, that means acting while the virus is still "smoldering;" an opportunity humanity did not have in 1918.

"The industrialization of poultry is the nub of this problem," says Shortridge. "We have unnaturally brought to our doorstep pandemic-capable viruses. We have given them the opportunity to infect and destroy huge numbers of birds and...jump into the human race."

An avian flu outbreak is potentially only as big as the flock it infects, reasons Shortridge. The larger the flock, the greater the surface area of risk for further onward transmission. Modern poultry-raising operations, in which tens of thousands of birds may be contained in a single shed, provide the greatest risk scenario in history.
According to this week's TIME, U.S. poultry farmers are taking "every precaution" possible to prevent an outbreak in their flocks, and are prepared to slaughter all their birds if/when an avian-flu infection is discovered.


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