Experts Puzzle Over Halt of Bird Flu

By Aussiegirl

Ah tolja an' ah tolja an' ah tolja!

Experts Puzzle Over Halt of Bird Flu - Forbes.com

Experts Puzzle Over Halt of Bird Flu
By MARIA CHENG

Earlier this year, bird flu panic was in full swing: The French feared for their foie gras, the Swiss locked their chickens indoors, and Americans enlisted prison inmates in Alaska to help spot infected wild birds.

The H5N1 virus - previously confined to Southeast Asia - was striking birds in places as diverse as Germany, Egypt, and Nigeria, and a flu pandemic seemed inevitable.

Then the virus went quiet. Except for a steady stream of human cases in Indonesia, the current flu epicenter, the past year's worries about a catastrophic global outbreak largely disappeared.

What happened?

Part of the explanation may be seasonal. Bird flu tends to be most active in the colder months, as the virus survives longer at low temperatures. [....]

While the pandemic has not materialized, experts say it's too early to relax.

"We have a visible risk in front of us," said Dr. Keiji Fukuda, coordinator of the World Health Organization's global influenza program. But although the virus could mutate into a pandemic strain, Fukuda points out that it might go the other direction instead, becoming less dangerous for humans. [....]

Flu viruses constantly evolve, so the mere appearance of mutations is not enough to raise alarm. The key is to identify which mutations are the most worrisome.

"We don't really know how many changes this virus has got to make to adapt to humans, if it can at all," said Dr. Richard Webby, a bird flu expert at St. Jude Children's Research Hospital in Tennessee. [....]

Though scientists are bracing themselves for increased bird flu activity in the winter, there are no predictions about where it might appear next. The WHO's Fukuda said it would not be a surprise to see it appear in new countries.

Copyright 2006 Associated Press. All rights reserved.