A worrisome new bird flu is spreading in American birds and may be here to stay

April 9, 20228:01 AM ET
Heard on Weekend Edition Saturday
Nell Greenfieldboyce 2010

As the virus moves across the country, and potentially settles in for the long haul, it will encounter new animal species that could get infected. This pathogen will also get a chance to genetically mingle with the flu viruses that are already circulating in the U.S.

"What that means for the virus in terms of how it evolves, how it changes, we just don't really know," says Richard Webby, a flu researcher at St. Jude Children's Research Hospital.
"We're concerned with any avian influenza virus that's circulating in domestic poultry or wild birds," says Todd Davis, an expert on animal-to-human diseases at the Centers for Disease Control and Prevention (CDC). "Because humans have no prior immunity to these viruses typically, if they were to be infected and spread the virus to other humans, then we could have another pandemic virus on our hands."

This virus doesn't have genetic features previously associated with related bird flus that have infected humans. And the only person known to have contracted this particular bird flu virus was an elderly person in the United Kingdom who lived in close quarters with ducks; while some of the ducks got sick and died, their owner never had any symptoms.

The CDC has been monitoring the health of more than 500 people in 25 states who were exposed to infected birds, says Davis. Although a few dozen people did develop flu-like symptoms, all were tested and none were positive for this virus.
"This outbreak in the wild bird population is a lot more extensive than we saw in 2014 and 2015," says David Stallknecht, an avian influenza researcher with the University of Georgia. "Just a lot more birds appear to be affected."
It remains to be seen how much of a toll this virus will take on American bird species.
The bird flu that struck in 2014 and 2015 resulted in the deaths of more than 50 million birds and cost the industry billions of dollars. Back then, the greatest number of cases occurred in the month of April.

"So I think I am kind of holding my breath this month," says Denise Heard, director of research programs for the U.S. Poultry & Egg Association.