An unprecedented number of people in the U.S. were infected with bird flu this past year. In this country, a lot of science focused on the virus in dairy cows and in poultry. But researchers say something ominous is happening in wild animals and not just birds. NPR's Gabrielle Emanuel reports
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EMANUEL: Now, this virus, H5N1, it's been around for decades. It originated in East Asia, infecting poultry and sometimes people. And it did periodically jump over into wild birds. But the virus killed them quickly before they could migrate, so the virus never took off globally. Then about five years ago, the virus changed. Erik Karlsson is the director of the Cambodian National Influenza Center.
ERIK KARLSSON: This new virus seems to be a bit more like dead bird flying, right?
EMANUEL: So a bird gets infected and will likely die eventually, but first...
KARLSSON: They seem to be able to still migrate further, and they contact another group of birds. They fly a little bit further, and that eventually gets all the way across the world.
EMANUEL: It's almost like a relay race. And that's what Michelle Wille has been mapping. She's at the Centre for Pathogen Genomics at the University of Melbourne. She says infected wild birds carried the virus to North America a few years ago, and then South America.
MICHELLE WILLE: So then in South America, it traveled the 6,000-kilometer spine in about six months, OK? So this is a virus. It's not assisted by airplanes. This is a virus that's traveling by mass mortality after mass mortality, after mass mortality, after mass mortality.
EMANUEL: Now, she says, the virus is racing around Antarctica. The problem globally is nobody knows how many wild animals the virus has killed.
WILLE: No one's counting. We have no idea. So it's been like a catastrophe. It is a global catastrophe.
EMANUEL: It's a catastrophe for the animal species and for the ecosystems they're part of. But on top of that, this matters for human health. People can get bird flu. But right now, the virus doesn't spread easily from one person to another. That could change. The estimates are millions of birds have been infected and tens of thousands of marine mammals. And each animal the virus infects, that's another chance for it to evolve.
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and as a bonus it's already killing some domestic(ish) animals like felines