Cold, Flu, & Cough Health Center

Bird Flu Woes: Flying This Way?

The Role of Wild Birds

What's now happening in wild birds is also something never seen before. Wild birds usually carry avian flu viruses that aren't very deadly -- low pathogenic avian influenza or LPAI. From time to time, one of these wild LPAI viruses gets into domestic chicken flocks, where it mutates into virulent, highly pathogenic avian influenza or HPAI. But the Asian H5N1 HPAI is breaking all the rules.

"What has not happened before, as far as we know, is for HPAI to go back into wild water fowl," Brand says. "That is where this virus is different. It has gone from poultry back into wild waterfowl. That is what we are seeing now. So we are dealing with things we haven't seen before."

Flu expert John Treanor, is director of the vaccine and treatment evaluation unit at the University of Rochester, N.Y. He agrees that the H5N1 virus is something new.

"This epidemic in birds has some features that are very unusual in our previous experience with bird flu viruses," Treanor tells WebMD. "There is no sign it is going to go away. It may be established as something persistently in the environment. And that means many more opportunities for human exposure. And every time a human gets infected, there is the opportunity for whatever needs to happen to happen."

Impact on U.S. Poultry

In Asia, the H5N1 virus has led to the death or destruction of an estimated 150 million chickens and ducks and has cost more than $10 billion. You might think the U.S. poultry industry would be in a panic. It's not, says Mike Lacy, PhD, head of the poultry science department at the University of Georgia.

"The industry is taking the perceived threat very, very seriously," Lacy tells WebMD. "But the U.S. poultry industry is protected because of the way it is organized. The best word for it is sophistication. Our birds are protected from migratory fowl. It is very unlikely that the Asian bird flu virus is going to get established in U.S. poultry flocks."

Bird flu spreads in Asia because vast numbers of chickens and ducks are raised in backyard farms. The U.S. poultry industry, however, is a bird of a different feather. The nation's gigantic chicken factories are very well contained.

That doesn't mean bird flu never happens here. It does. It last happened in 2004 in Texas -- with an H5N2 virus different from the Asian H5N1 strain.

"They swooped down, tested the infected flock, destroyed the infected and exposed birds, tested birds around the area, and kept the area quarantined," Lacy says. "That outbreak was stomped out in just a matter of a few weeks."