Bird Flu Woes: Flying This Way?
Experts discuss the potential impact of bird flu that could arrive in the U.S. via wild birds.
Bird Flu's Next Move
Scientists -- who think in the very long term -- see an eventual flu pandemic as inevitable. They hedge their bets by saying it might not be the deadly Asian H5N1 that causes the next one. Even so, this scary virus already seems ready to jump to humans. "Seems" is the key word here.
We knew about previous flu pandemic only when people started getting sick. This time, for the first time, scientists are able to watch the virus evolve. What they are seeing is cause for concern -- but there's no way to tell how likely it is that these concerns will become reality. This is the first time anybody has seen these things, says Stephen Morse, PhD, director of the Center for Public Health Preparedness at Columbia University, New York.
"It is a little like a clock striking 13 -- it is a whole new thing, and we don't know what to expect," Morse tells WebMD. "What flu strain is going to be the next pandemic and when? Many people come to grief trying to predict this. It does say something about our science. We have a limited handle on what achieving human-to-human transmission involves. It is not something we can predict very well."
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."