Researchers to gauge bird flu's lethal potential

By Emma Ross
The Associated Press

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LONDON — Scientists are experimenting with the bird-flu virus ravaging Asian poultry to see how dangerous it would be if it adapted to humans, the chief influenza expert at the U.N. health agency said yesterday.

Researchers will mix the virus with a human flu variety to see how well they swap genes and test various combinations on ferrets and other animals to determine which would be the most hazardous, said Klaus Stohr, chief flu expert at the World Health Organization, which is coordinating the tests.

"What we want to do is reduce surprises. Every surprise will cost lives," Stohr said in a telephone interview from Geneva. "We still have the time here to do the research. We don't have much time, but the pandemic isn't there yet."

The avian-influenza outbreak has forced the slaughter of more than 80 million chickens and other fowl in Asia, but human infections remain rare.

Experts agree it is only a matter of time before a deadly human flu pandemic develops, and most suspect the current bird flu strain is the most likely candidate to cause it.

"It's not a virus which we have been able to get rid of. It comes back, comes back, and these outbreaks are getting bigger and bigger," Stohr said. "This is the virus which everyone would bet their money on."

There are two ways the bird-flu virus sweeping Asia could become a serious danger to humans:

• It could accumulate enough genetic mutations on its own to become good at passing between humans. Experts are tracking the virus to detect any significant genetic changes, but so far none has been recorded.

• The more scary possibility would be a sudden change in the virus, brought on by combining with a human flu strain in someone's body. The two viruses could swap genes and create a potent hybrid with the deadliness of the bird strain and the contagiousness of a regular human strain. It takes only one person with a double infection to set off such a chain of events, Stohr said.
 
Studies in monkeys using only pure bird-flu virus will be conducted in Rotterdam, the Netherlands, at the same laboratory where key experiments involving the SARS virus were carried out, Stohr said.

Studying how the pure bird-flu virus behaves in monkeys is considered a good indicator of how a pandemic strain based on the virus could behave in humans.

Results are expected by the end of March.

Mexico, European Union

join ban on U.S. poultry

WASHINGTON — Mexico and the European Union joined a dozen other countries yesterday in banning U.S. poultry because of a bird-flu outbreak, threatening to cripple the $2.1 billion export market for U.S. poultry products and depress domestic prices.

The European Commission imposed a one-month ban on all U.S. poultry shipments, a day after the discovery of a virulent form of bird flu on a Texas chicken farm. Mexico expanded an earlier ban on poultry from 10 states to apply to the entire United States.

Big U.S. poultry buyers Japan, South Korea and China have also announced similar bans.

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