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Hey, shortwaivers, Regina Barber here to talk about the bird flu, also known as avian influenza.

It's spreading among livestock and other mammals in the U.S. and raising fears that another pandemic is in our future.

So bird flu got into the news when a farm worker was infected in the spring of last year,

and last month, California declared a state of emergency due to rising cases in dairy cattle.

So here to parse through the data is health correspondent Will Stone. Hey Will. Hey, Gina.

Will, you've been monitoring bird flu ever since the first case almost a year ago. And there's so much to

cover. But can we start with like a refresher? What's happened like so far? Sure things. So there

have been more than 65 human cases in the U.S. during this current outbreak. And there's reason to

believe that's probably an undercount. Luckily, these have largely been mild. Many are presenting

as conjunctivitis and sometimes as a cold, although there have been a few that have resulted

in serious illness. And just to refresh listeners, a bird flu infection starts when the protein on

the virus binds to a receptor on the cell it wants to take over.

This is the HA protein on the bird flu virus.

Luckily, the version of H5N1 spreading in cattle has not evolved to target the receptors that

dominate upper airways in humans, you know, in the way that people get infected with seasonal

influenza every year.

That would be a key step in the

path to this becoming a pandemic. But scientists warn, it could evolve, right, and be more

dangerous. I mean, do you have a sense of how worried scientists are? Yeah, scientists who study

influenza have told me they are about as worried as they've ever been about a potential

bird flu pandemic. Now, that doesn't mean it will necessarily happen. Dr. Jesse Goodman, an

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