Bird Flu: The Next Pandemic?

Bird flu has been in the headlines for ages, with scientists warning that we could be headed for a pandemic. But we’ve been hearing about this H5N1 virus for so long that it’s kind of starting to feel like the boy who cried wolf. So — what’s really going on with H5N1 bird flu? How scary is it, and how likely is it that we’re going to end up in a bird flu pandemic? We talk to virologists Dr. Seema Lakdawala and Dr. Richard Webby. Find our transcript here: https://bit.ly/ScienceVsBirdFlu (00:00) Tons of people are freaked out about H5N1 bird flu (03:38) Why H5N1 bird flu is scary (05:01) Birds are falling out of the sky dead (07:32) Things get weird when bird flu gets into mammals (18:34) What happens when humans start getting this bird flu (23:26) Is bird flu mutating? (29:11) Should I worry about bird flu? (30:50) Do we have anything to fight bird flu? (32:14) We have had some silent cases of bird flu already This episode was produced by Blythe Terrell, with help from Wendy Zukerman, Michelle Dang, Rose Rimler, Meryl Horn and Ekedi Fausther-Keeys. We’re edited by Blythe Terrell with help from Wendy Zukerman. Mix and sound design by Bobby Lord and Sam Bair. Fact checking by Erica Akiko Howard. Music written by Bumi Hidaka, Peter Leonard, Emma Munger, So Wylie, and Bobby Lord. Thanks so much to all the researchers we spoke to for this episode, including Dr. Louise Moncla, Dr. Ted Elsasser, Dr. John Korslund, Victoria Rosado and Lindsey Adams. Thanks to Jeff DelViscio. Science Vs is a Spotify Studios Original. Listen for free on Spotify or wherever you get your podcasts. Follow us and tap the bell for episode notifications. Learn more about your ad choices. Visit podcastchoices.com/adchoices

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Wendy Zukerman?

  Hi, I'm Wendy Zukerman and you're listening to Science Versus.

• 0:05Wendy Zukerman?

  Today on the show, we are putting facts against bird flu.

• 0:14Wendy Zukerman?

  And to tell us all about it is editor of Science Versus, Blythe Terrell. Hey, Blythe.

• 0:19Wendy Zukerman?

  Yeah, hey, Wendy. So you've spent the last few months, I feel like, coming into meetings and saying, "Oh, my God, I just learned something crazy about bird flu. Oh, my God, Wendy." And I have kept telling you to wait for this conversation right here. So...

• 0:36Speaker 02

  The day has finally come when I get to talk to you about bird flu.

• 0:39Wendy Zukerman?

  The day has come. Tell me this crazy stuff you're hearing about bird flu.

• 0:43Speaker 02

  Yes, I will, I will. And actually, Wendy, I will say it's been years that we've been talking about bird flu, not mere months.

• 0:49Wendy Zukerman?

  It's true, it's true. I mean, when I think about it, the alarm bells about bird flu, just in general, becoming a global pandemic, I feel like they've been going on and off and on again for like 20 years. I mean, to be honest, it is feeling a little boy who cried wolf at this point. I mean, has something changed?

• 1:11Speaker 02

  Yeah, right. Yeah, what's different? What's different? That is an extremely fair question. I can say there are a few things that have kind of tipped things over the edge here. And for one thing, we have had poultry farms being hit super, super hard.

• 1:26Speaker 03

  So right now, the biggest outbreak of bird flu in US history is sweeping across this country, leaving millions of hens dead.

• 1:33Speaker 02

  Since the outbreak started in 2022, the avian flu has impacted more than 135 million birds. We're hearing about these super high egg prices. You can't find eggs, which is partly because of bird flu.

• 1:44Speaker 04

  Eggflation is back for the vengeance, and it's cooking the family's grocery budget. Are they going up more? Are all the birds gonna die?

• 1:52Speaker 02

  Wendy, I have seen reports of egg smuggling, like people getting busted bringing eggs across the border. Also, in New York City, in the Bronx, the bodegas are selling egg Lucy's. Like, you know, you can usually buy like one cigarette at a time. They're selling like two eggs at a time.

• 2:08Wendy Zukerman?

  In Australia, too, eggs crazy. Crazy expensive right now. Supermarkets empty, kind of like the pandemic when the, where the toilet paper used to be. Just like, it's kind of like that, but for eggs.

• 2:19Speaker 02

  Yeah, and I mean, it is really like blowing up beyond chickens and eggs. So, you know, at this point, they found the bird flu in like all sorts of animals, more than 450 species.

• 2:29Wendy Zukerman?

  Recent tests show avian flu was detected in foxes, raccoons, skunks, and even domestic cats.

• 2:36Speaker 05

  Many health experts are calling this a global pandemic of animals.

• 2:40Speaker 02

  The UN has called the spread in animals, quote, "unprecedented," actually.

• 2:43Wendy Zukerman?

  Uh huh.

• 2:44Speaker 02

  And then, yeah, like, all this is happening while the Trump administration is making cuts to science and to a bunch of the agencies that handle public health in the US.

• 2:51Wendy Zukerman?

  Right.

• 2:52Speaker 02

  So with all this going on, we are just getting this steady drumbeat of headlines and news reports saying that this bird flu is the real deal. No more boy who cried wolf, Wendy. It's only a matter of time before this thing could totally blow up and land us in another global pandemic.

• 3:10Speaker 06

  What I'm here to tell you is, this is a very serious threat to humanity.

• 3:15Wendy Zukerman?

  When we say we are in emergency mode, that is the mode we are in right now. Could potentially lead to another pandemic.

• 3:25Wendy Zukerman?

  Oh, man. Are they riot? That's what we're gonna find out after the break.

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• 6:10Wendy Zukerman?

  Welcome back. Today, we're talking about bird flu. Blythe is about to tell us if this is gonna be the next pandemic.

• 6:17Speaker 02

  Okay, yeah, so I want to start actually by talking about why exactly this bird flu scares the crap out of us so much.

• 6:23Wendy Zukerman?

  Okay.

• 6:24Speaker 02

  And a huge reason is that generally speaking, this type of bird flu, H5N1, can be really deadly for humans. Like, some of the warnings out there say that if we do get a bird flu pandemic, it could kill 100 million people.

• 6:39Wendy Zukerman?

  Why do they think that?

• 6:41Speaker 02

  Yeah, so there's a couple of reasons, right? So, you know, if you look at past flu pandemics, like, often a lot of people get sick. And this flu has a really high fatality rate. So when humans get this kind of bird flu, it tends to kill 50 to 60% of the people who get it. And, you know, with the caveat that there are some people who get bird flu and we don't know about, so maybe that death rate is a little high. But still, I mean, over the past few decades, on and off, about 1,000 people have been diagnosed with this, H5N1, and about half of them have died.

• 7:12Wendy Zukerman?

  Wow. And so how exactly are people dying from bird flu?

• 7:17Speaker 02

  So when bird flu gets, like, really bad in a person, they can get this terrible fever, they can't breathe, they might go into respiratory failure, and sometimes their organs will fail too. They can get inflammation in their brain. It's really, it can be really bad.

• 7:32Wendy Zukerman?

  So, bird flu has been going around for a while now, every now and then, killing people over the last 20 years. What's been happening recently?

• 7:42Speaker 02

  So, over the years, there's been all these different types. And, I mean, I've been talking about H5N1, sort of this umbrella type. But then, several years ago, something changed the game here. So, H5N1 has been making virus babies, let's call them. Each one a little different. These are different clades. Clades is what they're called. And then this one called 2344B popped up.

• 8:08Wendy Zukerman?

  2344B, it's called.

• 8:14Wendy Zukerman?

  I didn't realize that when they started calling those coronavirus variants Delta and Omicron, that they were big or fancy with us.

• 8:22Speaker 02

  Yeah, I know, I know. We didn't realize, most of the time, it's these really nerdy number names that are a little bit hard to keep track of.

• 8:28Wendy Zukerman?

  Okay, so, but this 2344B, that is what people are freaking out about right now?

• 8:36Speaker 02

  Yeah, mhm. And, I mean, that's because when it started showing up in wild birds, it was clear that something was really different about this guy.

• 8:44Wendy Zukerman?

  Okay.

• 8:45Speaker 02

  I talked about this with Seema Lakdawala, who is a virologist at Emory University. And so Seema came across this because she works with other nerds who monitor bird flu like worldwide. And she remembers first hearing about this virus from some other scientists out of the UK.

• 9:01Speaker 09

  It was a 2021 where like, birds were just falling out of the sky dead.

• 9:06Speaker 02

  Wait, like, wait, they were like literally falling out of the sky dead?

• 9:09Speaker 09

  Yeah, yeah, that's their description. We've had more birds fall out of the sky. Like, it is bad.

• 9:14Speaker 02

  I actually watched a video of this bald eagle with bird flu. And it's like flying down to the ground, and it stumbles, and it like can't really land, and it's trying to walk, and it's going around in circles, and it's just like shaking its head, shaking its head all over the place.

• 9:27Wendy Zukerman?

  Oh, gosh.

• 9:28Speaker 02

  It's really sad.

• 9:28Wendy Zukerman?

  And so scientists are seeing all these awful deaths in birds?

• 9:33Speaker 02

  And of course, what can happen with bird flu is that it moves with the birds, who also move. So it makes its way to other countries, including the US. And we start seeing it in wild birds and in chickens. And this is like late 2021, 2022.

• 9:48Speaker 09

  Okay.

• 9:49Speaker 02

  And so in the US, what we do when this happens, when it shows up on like a poultry farm, whatever, we kill those birds. And we are killing millions of birds, which is definitely like one thing that can make eggs more expensive, right? You got fewer birds, you get fewer eggs.

• 10:02Speaker 09

  Right.

• 10:03Speaker 02

  So overall, as this happens, though, when it first kind of pops up, it's not ringing like huge alarm bells for humans, right? Like, it's crappy, but we're kind of used to bird flu in birds.

• 10:11Speaker 09

  Right.

• 10:12Speaker 02

  But then, this virus starts showing up in like more and more mammals.

• 10:15Speaker 09

  Hmm.

• 10:16Speaker 02

  And scientists always keep an eye on that. Because...

• 10:21Speaker 02

  Once a virus starts like jumping species, maybe adapting to these different hosts, you start to worry that it could get to a point where it is easier for it to move from human to human.

• 10:32Wendy Zukerman?

  Which at this point hasn't really happened.

• 10:34Speaker 02

  Right, but here is SEMA. Every time a virus, like a bird virus, gets into a mammal, it can then adapt to that mammal, right? Because viruses change. We know this. Covid, right? Omicron, Delta. Like, you know, I'm saying things that people remember. Viruses change when they infect hosts.

• 10:53Wendy Zukerman?

  Uh huh, okay.

• 10:54Speaker 02

  So we're finding this new bird flu in all these different animals. But the important thing that happens next in our story is when it shows up in this particular mammal. We've had sporadic spillover events from birds into seals in lots of different places, right? You might remember this?

• 11:12Wendy Zukerman?

  Seal outbreaks. Oh, yeah. And so this is 2022, where are we?

• 11:19Speaker 02

  2022, 23.

• 11:20Wendy Zukerman?

  Okay. Yeah, how did the seals get it?

• 11:23Speaker 02

  So we don't know for sure. But it could be that seals live along the shorelines, like along the waterline. And you also get a ton of birds who live and hang out in that same space, right? So we're thinking, oh, maybe the birds are crapping on or near the water. And the seals are like, maybe they're licking it up. Maybe they're swimming in like bird crap-infested waters or whatever.

• 11:42Wendy Zukerman?

  Pooh, I thought it was the crap. Those birds crap so much. And so they're crapping out the virus.

• 11:49Speaker 02

  Yeah. And, well, the thing is that it wasn't just the dead seals that like freaked people out here because they were sad about seals. The important thing was that the seals started giving this virus to each other.

• 12:03Wendy Zukerman?

  Oh.

• 12:04Speaker 02

  So they think it wasn't just like one seal sucks up some bird crap, another one does, another one does. They think the seals were actually spreading it. And this kind of thing is pretty unusual. You know, bird flu going mammal to mammal. It's not the first time. But scientists start to worry that this could help it mutate to where it could go human to human.

• 12:23Wendy Zukerman?

  Oh.

• 12:26Speaker 02

  Okay, so at this point, when we start to see all these dead seals, I asked Seema, like, how she was feeling. And she actually said she was not freaking out.

• 12:34Wendy Zukerman?

  It's not terrifying yet.

• 12:37Speaker 02

  Okay.

• 12:37Wendy Zukerman?

  She's, okay, not terrifying yet. Yet. Noting the yet. Interesting. It's just a sign that, huh, we don't like that. But a seal is not a human. That seems like that's her mindset.

• 12:52Speaker 02

  Exactly. Also, I mean, humans don't hang around seals all that much, right? So we have a low chance of getting it from them. Which kind of leads me to what you might be wondering, which is, when does it get terrifying?

• 13:05Wendy Zukerman?

  Hmm.

• 13:05Speaker 02

  For people like Seema. The biggest shift in my perspective happened in March and April of 2024. That was when it was first identified in cattle.

• 13:17Wendy Zukerman?

  Cattle? Why, oh, I was so sure she was gonna say humans. So why, I mean, cows just feel like seals of the land. Why is she worried about cattle?

• 13:28Speaker 02

  I believe that's actually what farmers call them, is the seals of the land.

• 13:33Wendy Zukerman?

  They've got those big eyes, you know?

• 13:35Speaker 02

  Sure, charismatic megafauna.

• 13:38Wendy Zukerman?

  Yes.

• 13:38Speaker 02

  The reason, so I asked Seema that question. I asked why the cows matter.

• 13:43Wendy Zukerman?

  Yeah, so I'll tell you two reasons why I think it's really important. The first one is that they're farm animals, they're domestic. Humans have a lot of interaction with these animals compared to, say, seals.

• 13:55Speaker 02

  She's like, cattle? We've got cattle all over this country. We have people giving them medicine, helping them give birth, milking them, feeding them, tending them when they're sick.

• 14:06Wendy Zukerman?

  Okay.

• 14:07Speaker 02

  But there's also other reasons why scientists kind of freak out when the cows get it. And one of them is that, as far as we knew, cows generally, like, did not get this kind of flu.

• 14:17Wendy Zukerman?

  Mm-hmm.

• 14:18Speaker 02

  So this bird flu belongs to this group of flus known as influenza As, which just like are not much of a thing in cows. I mean, one virologist actually told me that people in his science community, they would like test cows for influenza A and he would like laugh at them because he was like, it was so dumb to think that a cow could get this kind of flu.

• 14:36Speaker 09

  Oh, because they were so sure, you know, these cows don't have it.

• 14:39Speaker 02

  Yeah, exactly. Yeah. And because of this, it was like actually really impressive how scientists figured out that it was bird flu in the first place. So Wendy, we were lucky to have some very clever nerds on the case. And, um, yeah. And it basically started with some dairy cows in Texas that were looking a bit sick. They were eating less. They were like maybe pumping out a little bit less milk. And they actually had mastitis in their udders.

• 15:03Speaker 09

  So this is where like the, the milk from a cow becomes like yogurty and yellowy and chunky. And it's typically caused by bacteria.

• 15:12Speaker 02

  Okay. So these veterinarians, they ran their tests. They did their thing. They were like, okay, is it this? Is it this? It doesn't seem to be any of these infections we thought it was.

• 15:20Speaker 09

  Right.

• 15:21Speaker 02

  And they were like, pretty confused. And so then a veterinarian went on the farm and noticed some dead birds and a neurologically sick cat, like a cat with neurological symptoms.

• 15:34Speaker 09

  Whoa, this is like house. This is like.

• 15:36Speaker 02

  Yeah, like, right? It's super, it's super, like, again.

• 15:39Speaker 09

  Detective work.

• 15:41Speaker 02

  Right. And then of course, they work out that it's bird flu.

• 15:44Speaker 09

  Mm hmm. And the bird flu was giving the cat neurological symptoms and the cow's mastitis.

• 15:52Speaker 02

  Yeah, right. Which is like kind of crazy. And what's interesting here is that they didn't just like pop a swab up the cow's nose and swirl it around in there. They also tested the milk.

• 16:05Speaker 09

  And what they found was like massive amounts of virus in the milk. And when I talk about massive amounts, like it is scary how much virus is in the milk of a cow. And I'm talking 10 million to 100 million infectious particles in one milliliter, one milliliter of milk. Oh gosh. Was the virus alive? I mean, are we drinking that virus?

• 16:33Speaker 02

  The virus that is actually in the milk is alive. Are we drinking it?

• 16:40Speaker 02

  If you are drinking pasteurized milk.

• 16:42Wendy Zukerman?

  Right.

• 16:44Speaker 02

  Pasteurization does seem to kill the virus.

• 16:47Wendy Zukerman?

  Okay.

• 16:48Speaker 02

  From everything I've found, like, there's already, there's been a lot of research on this where they're like, the pasteurization process seems to make the milk safe.

• 16:54Wendy Zukerman?

  Right.

• 16:55Speaker 02

  Now, where you might run into problems, Wendy, is if you are drinking raw milk.

• 17:01Wendy Zukerman?

  Yes.

• 17:01Speaker 02

  Which is, the whole point of it is it's not pasteurized, right?

• 17:04Wendy Zukerman?

  Right.

• 17:05Speaker 02

  For real, it is like not a good idea to be drinking that right now. Like, people are playing with fire because they could be straight up drinking bird flu.

• 17:11Wendy Zukerman?

  Got it. Do not drink raw milk in this moment.

• 17:14Speaker 02

  Correct. If you take nothing else away, Wendy, take that away from this.

• 17:18Wendy Zukerman?

  It's taken away. Yep.

• 17:21Speaker 02

  And the same goes for unpasteurized cheese, by the way.

• 17:23Wendy Zukerman?

  Oh.

• 17:25Speaker 02

  Yeah. And we actually do know that eating bird flu virus, like, it can get animals sick. And in fact, it's one way that cats are getting it, by drinking raw milk or eating raw pet food. And raw pet food, which can be like, stuff like ground up chickens or turkeys, that has made some cats sick and some of them have died.

• 17:43Wendy Zukerman?

  Oh, and, and eggs? Is it okay to eat eggs right now?

• 17:48Speaker 02

  Yeah, they say basically as long as you're, you know, cooking up your eggs, well, they think eggs are safe.

• 17:55Wendy Zukerman?

  Uh huh. Don't be guest on-ing in this moment.

• 17:57Speaker 02

  Oh, my god.

• 17:58Wendy Zukerman?

  Five dozen eggs, don't do it.

• 18:00Speaker 02

  Right. Don't guest on your way to getting bird flu, please.

• 18:05Speaker 02

  The other thing that I would just want to point out is that it's showing up in cows and we're like really not doing all that much to stop it. Like, definitely not to the level of what we do with other animals, chickens.

• 18:15Wendy Zukerman?

  We're not killing the cows, in the same way we would the chickens?

• 18:19Speaker 02

  Yeah, exactly. And I mean, it kind of makes sense that we're not killing the cows because like, what's reassuring is that a lot of the cows are surviving. It's not like they're getting super, super sick from this bird flu.

• 18:31Wendy Zukerman?

  So then, okay, so we're seeing all of these animals get it. That this was, we're up to last year with the cows.

• 18:37Speaker 02

  Yeah, so once it gets into cows, it starts spreading among the cows like crazy.

• 18:43Wendy Zukerman?

  Oh, gosh.

• 18:43Speaker 02

  So it's so far been found in more than a thousand herds of cows in 17 states in the US.

• 18:51Wendy Zukerman?

  Mm hmm.

• 18:52Speaker 02

  And I will tell you one more thing, Wendy.

• 18:53Wendy Zukerman?

  Oh, yeah, so this is, oh, this is also one of the most interesting things that I've learned.

• 18:57Speaker 02

  Yeah, so to go back to one of the big concerns here, that we end up in a situation where the virus gets in more and more animals, more and more animals. Now that the cows have it, we think a whole bunch of new animals might also be at risk.

• 19:09Wendy Zukerman?

  Yeah.

• 19:10Speaker 02

  And that's partly because of this disgusting and kind of fascinating thing called a manure lagoon.

• 19:17Wendy Zukerman?

  Oh, it sounds like a 90s band.

• 19:20Speaker 02

  You wish it were a 90s band, Wendy. And here's Seema.

• 19:24Speaker 09

  When a cow is sick, it had, like, say with H5 or with any bacterial infection, it has to be milked, right? It's inhumane to not milk a lactating cow. And so it is this, like, yogurt chunky milk, right? The smasite is milk. So it is not make it into our drinking milk. It gets collected separately and then it is poured into typically on farms into what's called a manure lagoon.

• 19:46Wendy Zukerman?

  Oh, no.

• 19:47Speaker 09

  And this manure lagoon is this large area where there's water, so there's always birds, like, feeding at it. The milk is not treated in most cases before it is poured into the manure lagoon. And again, just remind you, like I said, 10 million to 100 million virus infectious virus particles per small milliliter. This is one of the ways we think that peri-domestic animals on farms, near farms, are getting infected, right? Because it's just in the environment.

• 20:15Wendy Zukerman?

  Oh, no. Don't, don't put the milk in the manure lagoons. Oh, my gosh.

• 20:21Speaker 02

  So it's like, it's just in the environment. It's just out there.

• 20:25Wendy Zukerman?

  So, okay, so there's all this potential for humans to now get infected, not just from the cow to human interface, but also the cat-to-human interface, and the rodent-human interface, and the raccoon-human interface, and the opossum. I'm sure those opossums are also getting it. So where are we at now?

• 20:49Speaker 02

  Yeah, so after the break, we hear what happens when humans get this new type of bird flu.

• 20:57Wendy Zukerman?

  Coming up.

• 21:04Wendy Zukerman?

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• 22:15Wendy Zukerman?

  Welcome back. Today, I'm here with Blad, our editor at Science Versus. Who's about to tell us what bird flu is currently doing in humans. Where, what's going on?

• 22:28Speaker 02

  Okay, so we heard about the cows, all the birds, the seals, all these other animals, right?

• 22:32Wendy Zukerman?

  Yes.

• 22:32Speaker 02

  So after all this cow stuff starts popping off, pretty quickly, we start getting reports of bird flu in humans in the US.

• 22:39Wendy Zukerman?

  And they're now getting that newish version, that H5N1 baby that you were talking about?

• 22:46Speaker 02

  Yes. So in the US, we start seeing cases in people around March 2024. That's when we get the first known case of someone getting it from a cow. And actually, scientists think that not only is this the first time that they know about that bird flu has gone cow to human, they actually think that this is the first time they know about that any mammal has given bird flu to any human.

• 23:10Wendy Zukerman?

  Oh, because we normally get it through the birds.

• 23:12Speaker 02

  Right, right, yeah, we normally get it directly from a bird.

• 23:15Wendy Zukerman?

  Okay.

• 23:16Speaker 02

  And some people in the US do start getting it from birds, too. So overall, in the past couple of years, we've seen about 70 known cases of this bird flu in the US, of this H5N1 baby.

• 23:29Wendy Zukerman?

  Uh huh, 70 known cases. And so what's happening now when people get it? Are they, are they getting really sick?

• 23:37Speaker 02

  Yeah, so actually, this is what's pretty surprising. So despite all the scary headlines, every time someone gets bird flu, generally speaking, people who have gotten this in the US are not getting that sick.

• 23:48Wendy Zukerman?

  Oh.

• 23:49Speaker 02

  We are mostly seeing people who have flu-y symptoms, your typical stuff, fatigue, respiratory. We do see this one weird symptom that I want to talk about for a sec, cropping up a lot, because a lot of people are getting conjunctivitis or pink eye. Actually, one study looked at this, the people who'd gotten it, and found that 93% of them had gotten pink eye, which is like, not typical for flu.

• 24:10Wendy Zukerman?

  No, that is, that is strange.

• 24:13Speaker 02

  Yeah, but overall, like, a lot of people are getting these sort of like milder symptoms.

• 24:18Wendy Zukerman?

  Good news, great news there.

• 24:20Speaker 02

  But then, there are some serious cases where things played out really differently. And I want to talk about a couple of those.

• 24:27Wendy Zukerman?

  Okay.

• 24:28Speaker 02

  So there's one. In Canada.

• 24:30Speaker 09

  Canada's first human case of bird flu has everyone talking.

• 24:33Speaker 05

  Canadian teenager with the virus has been actually hospitalized in critical condition.

• 24:38Speaker 02

  Had to be on lifesaving machines, super scary, ends up surviving. And then there's a person in Louisiana who, same thing, gets really sick and ends up in the hospital, and that person ends up dying.

• 24:51Speaker 11

  For the first time, bird flu has claimed a human life in the US. The first person to die of bird flu, it's alarming.

• 24:58Speaker 08

  That's right, because this feels like it was a threshold, an alarm bell sounding.

• 25:03Speaker 02

  And when the scientists genetically tested the virus that's in these two people, they're like, oh, no, this is a slightly different type of bird flu. Because H5N1's baby, she's got babies of her own. And this particular baby, it seems to be making people sicker, and it is spreading in birds, and now also in the cows.

• 25:35Wendy Zukerman?

  Oh, no.

• 25:36Speaker 02

  Yeah, and we've since seen a few more cases of it in the US, a couple more people hospitalized. In addition to this, you know, we are seeing bird flu cases and deaths in other countries, too, in H5N1. It's showing up in Cambodia, it's killed several people there, including children. We just had a child die in India, a child in Mexico, and we don't always know exactly what, which of these types of H5N1 it is, which version, if it's this creepier one, if it's something else. In some cases, though, it does seem likely that it is.

• 26:11Wendy Zukerman?

  Mm-hmm. So, so these cases, they're kind of trickling out, but the question obviously becomes, have we had a case where the virus has gone human to human?

• 26:24Speaker 02

  That is 100% the question, right? Because that, if that starts happening, Wendy, like, that's when we're like, we've got an outbreak.

• 26:33Wendy Zukerman?

  Yes.

• 26:33Speaker 02

  And we start freaking out about a pandemic, right?

• 26:36Wendy Zukerman?

  Exactly. Then we're like the seals, you know?

• 26:39Speaker 02

  Yeah, exactly. So is that happening? Here's what Seema told me about what's been going on in the US.

• 26:47Speaker 09

  There has been no documented human-to-human transmission. Does that mean it hasn't happened? No.

• 26:57Speaker 02

  So basically, there are a few cases of people who've gotten bird flu, and we just don't know how.

• 27:02Speaker 02

  Like, they're not agriculture workers.

• 27:04Wendy Zukerman?

  Right, OK. And we don't know if those people got it through wild birds, through another person. That's so difficult to know. When you look at the genetics of the virus, does it give us any clues about where this might go?

• 27:22Speaker 02

  The big thing scientists are watching is exactly that, Wendy. Like, it's exactly the genetics of the virus. Like, they're watching how this thing mutates. Because what they want to see is if it ends up mutating in a way that makes it way easier to spread from one person to another.

• 27:38Wendy Zukerman?

  Mm-hmm, yes.

• 27:39Speaker 02

  And one of the scientists who is watching this is a guy named Richard Webby. He's a virologist at St. Jude Children's Research Hospital in Tennessee. I did come across an article that called you "The Flu Catcher." What do you think about that nickname?

• 27:52Speaker 12

  Yeah, I'm not sure. I must admit, I don't do much catching of flu myself anymore.

• 27:57Wendy Zukerman?

  What's he do? What's he doing on our bird flu episode, then?

• 28:01Speaker 02

  He was mostly like, "My kids aren't in daycare anymore."

• 28:03Wendy Zukerman?

  Oh, OK.

• 28:05Speaker 02

  So Richard tells me that flu viruses, including bird flu viruses, are generally really good at mutating. And that's partly because when they get inside an animal or a person and start making copies of themselves, they tend to make a whole bunch of little mistakes. And then, in some cases, those mistakes are very helpful and, like, help them adapt.

• 28:24Wendy Zukerman?

  Right, so they can then infect seals and cows and other animals.

• 28:29Speaker 02

  Yeah, exactly. And so I asked Richard, "At this point, how likely do you think it is that this H5 virus will start moving from human to human?"

• 28:39Speaker 12

  Yeah.

• 28:41Speaker 02

  I know, you're shaking your head.

• 28:42Speaker 12

  Yeah, you can see it.

• 28:45Speaker 02

  You love this question, I can tell.

• 28:46Speaker 12

  I love it a lot, right? What is the risk?

• 28:51Speaker 12

  So I'll tell you why I find that difficult to answer.

• 28:56Speaker 12

  If we look today, so right now, today, even let's look at the viruses in cows. Even the viruses that we get from people that have been infected. They still have all the characteristics of bird viruses. They want to be infecting birds.

• 29:11Speaker 02

  Yeah, like they look like the virus that you're pulling out of a goose or a chicken or a turkey or whatever. I mean, they haven't like really adapted to be good at infecting humans. Got it. Generally, which is good news, except.

• 29:24Speaker 12

  The problem is this virus could be two, three, maybe even one mutation away from changing that.

• 29:34Speaker 02

  Yes. So scientists don't think it'll take that much mutating at all to get to a version that could have the capacity to spread more easily. And actually, there was like a big paper that was looking at this in the lab and actually identified one mutation. They were like, oh, if you flip this switch. That's all it takes. That's a version that'll probably be easier to get into people. Ah. And we do know that this bird flu can get certain mutations like this out in the wild. Because you know those two patients, Wendy, who got really sick and one of them died? Yeah, yeah, yeah. They were sick for so long that scientists think the virus did mutate inside their bodies. And when they looked at the virus's genetics, like some of the virus in those people

• 30:16Speaker 02

  did have mutations that might have made it easier to spread from person to person. Wow. Which is interesting because it didn't in those cases. Yes, right. Which brings me to perhaps like a kind of surprisingly optimistic point. Some good news, if you'll have it. I'll take it. I'll take some good news. So like, we've seen it mutate. It's gotten into a fair number of people. It hasn't yet broken out, as far as we can tell, in any meaningful way. And Richard told me that scientists are really debating what that means.

• 30:52Speaker 12

  So some people look at that, even some experts, look at that and say, H5 can never become a human pathogen, and that's-

• 30:59Speaker 02

  Really? They say it never can?

• 31:01Speaker 12

  That's right. It's just not able to do it, right?

• 31:03Speaker 02

  They say it would have happened by now, if it could?

• 31:05Speaker 12

  Right. That's right. It could. I mean, the argument against that, I'm not in that boat. I think the virus probably can, but the barrier to it making those key changes is relatively high.

• 31:18Wendy Zukerman?

  Yeah, that's interesting, and that's not really a gamble we want to make.

• 31:22Speaker 02

  Right, yeah. And there's this other thing that could happen that could screw us on this. It is called reassortment, and it's where different types of flus are kind of able to mix together. So the deal with that is, say, I get infected with the regular human flu, and I'm a poultry worker, and I go in to work, and I get exposed to bird flu. And both of these flus manage to get inside my body at the same time. What can happen is that they can kind of mix and match inside of me, and that is reassortment. And that's actually, that process has triggered, one scientist told me, basically all the major flu pandemics in modern history.

• 32:05Wendy Zukerman?

  Oh, where a human flu, or a human-adapted flu, basically has virus sex with an animal flu. And then, because that's a, yeah, from a virus's perspective, that's a much more efficient way to just get all of these adaptive features that are like, bip, bip, bip, bip, I'll take this, and now we can infect humans much easier-

• 32:28Speaker 02

  Exactly.

• 32:29Wendy Zukerman?

  -than having to completely develop all these-

• 32:31Speaker 02

  Rinky-dink, mutation by mutation by mutation by mutation. So that's another thing that they're really watching for.

• 32:38Wendy Zukerman?

  Oh, okay. So that good news was short-lived.

• 32:45Speaker 02

  It always is, isn't it, on Science vs. I mean, and overall, big picture, like, when we talk about these viruses and how this flu is mutating and what could happen, where it could go, how it could mix with other viruses. What scientists told me is that it's a numbers game. You know, the more chances you give it, the more you give it chances to have virus sex, the more likely it is that it'll mutate into something that I can give to you and that you can pass along.

• 33:13Wendy Zukerman?

  Yeah.

• 33:14Speaker 02

  Here is how Seema is thinking about it at this moment.

• 33:17Wendy Zukerman?

  What we're allowing this virus to do is take 1,000 shots on goal every day, maybe 10,000 shots on goal.

• 33:25Speaker 02

  When would you worry?

• 33:26Wendy Zukerman?

  I'm already worried. Sorry, if that's not coming across, let me make it very clear. I am worried.

• 33:32Speaker 02

  Given all of this, right, I asked Richard. Let's see, where's Dr. Richard Webby's worry meter?

• 33:39Speaker 12

  So somewhere between, yeah, sitting back with my feet up on the recliner and, as I tell people, running, you know, heading towards the hills, I'm in the middle. I think I'm square in the middle a little bit.

• 33:50Speaker 02

  Is that like buying a few extra masks? Is that toilet paper?

• 33:54Speaker 12

  I think that'll be the key. If my neighbors see me, see me arriving back from Sam's Club with four or five extra packets of toilet paper, then they will know I've changed.

• 34:05Wendy Zukerman?

  You mentioned buying a few extra masks. Would that help?

• 34:10Speaker 02

  Yeah. For humans, generally tends to be a respiratory virus. Like, that's what we see. So I do think masks would help.

• 34:16Wendy Zukerman?

  Right. And this is still a flu. It's still a flu. That's right.

• 34:19Speaker 02

  It's still a flu. I mean, Wendy, I did buy masks last week.

• 34:22Wendy Zukerman?

  Oh, OK. But extra toilet paper? Did you do that yet?

• 34:25Speaker 02

  Uh, no, still taking my chances on that one.

• 34:28Wendy Zukerman?

  So do we have anything to, to fight against bird flu? Are there vaccines?

• 34:32Speaker 02

  Yeah, there are vaccines. You can't just go get one at the pharmacy. They're not, like, available, but they do exist.

• 34:39Wendy Zukerman?

  Great.

• 34:39Speaker 02

  But as far as how they would do if bird flu really took off?

• 34:42Speaker 12

  The good answer is we don't know, really, right? Because we've never had a pandemic in humans. Yeah, we've never had a pandemic to know how good they are in humans, which is a good thing.

• 34:52Speaker 02

  And we have stuff like antivirals that can help, too.

• 34:55Wendy Zukerman?

  It's funny because I have to go get my flu vaccine now because it's an early human flu season in Australia. And but it did make me think that is this something that you can do?

• 35:08Speaker 02

  Yeah, I mean, look, it's not going to do anything specifically for bird flu. They're just different enough. But you should do it. You should do it.

• 35:14Wendy Zukerman?

  Hmm.

• 35:15Speaker 02

  I mean, a lot of scientists reminded me that the regular flu, Wendy, I mean, it kills thousands of people every year. Like, that's still going on. And getting the flu vaccine does reduce the chance that, I mean, if you happen to be very unlucky, right, and also get bird flu,

• 35:31Wendy Zukerman?

  Mm hmm.

• 35:32Speaker 02

  get that reassortment thing that we're talked about, that you, Wendy, you know, will be patient zero of the bird flu pandemic. And actually, one of the things that Health and Human Services Department here in the US told me is that they are actually giving agricultural workers access to the seasonal flu vaccine as kind of part of their strategy here.

• 35:51Wendy Zukerman?

  Uh huh. And so then, just finally, what is the US government saying about all this?

• 35:56Speaker 02

  So, I mean, yeah, overall, like, bird flu does not really seem to be a big focus right now. You know, at the USDA, they are looking at ways to stop it in chickens. But like I mentioned at the start of the show, you know, the Trump administration's also like firing tons of people, including people whose job it was to work on diseases like this.

• 36:14Wendy Zukerman?

  Hmm, right.

• 36:16Speaker 02

  Yeah, and I mean, you know, the thing I'm actually kind of freaked out about here, Wendy, is like whether we're really going to be able to track this thing properly, you know, given everything that's going on. Like, how soon would we really know if it's starting to gain steam and spread in people? And one reason this has been on my mind so much is, so when I first started working on this episode, you know, watching all this last year into this year, human cases were kind of ticking up, kind of a few at a time, here and there. There's reports, there's news reports, data's coming in. And it was early this year, like around February, when we hit that 70 cases or so that I mentioned, right?

• 36:55Wendy Zukerman?

  Yeah, yeah, yeah.

• 36:57Speaker 02

  And so where we are now, it's May, more than two months later, and we're still like supposedly at 70 cases.

• 37:06Speaker 02

  And that just makes me a little suspicious, right? Because the flu is still showing up in cows. It's still showing up in new herds of cattle, right? There have been almost 50 new cattle herds infected in just the past month.

• 37:18Wendy Zukerman?

  Mm hmm. We're getting data on the cows. It's still clearly spreading, but.

• 37:22Speaker 02

  Yeah, so are like, are we really not getting more cases in people? It's just so hard to know if we can trust that.

• 37:29Wendy Zukerman?

  Hmm, that is scary.

• 37:32Speaker 02

  Yeah, and there is one more thing, you know, that that I guess gets my spidey sense on this tingling.

• 37:39Wendy Zukerman?

  Yeah.

• 37:40Speaker 02

  So there was this CDC report out a couple of months ago, like before all these firings really got going, where what they had done is they had tested a bunch of veterinarians who work on large animals, right?

• 37:52Wendy Zukerman?

  Uh huh.

• 37:53Speaker 02

  And they found that three of them had antibodies for this bird flu for H5N1.

• 38:00Wendy Zukerman?

  Okay.

• 38:01Speaker 02

  Yeah, but they hadn't really been sick. And in some cases, they, these vets hadn't even known they were working with infected animals in the first place. So what this tells me, right, is that there have been at least some silent cases of this flu already floating around.

• 38:18Wendy Zukerman?

  Oh, gosh, what does this tell us? What does this tell us? Because it means they didn't even know they were sick.

• 38:23Speaker 02

  Mm hmm.

• 38:24Wendy Zukerman?

  So asymptomatic infection is a thing. That also could suggest maybe this, this type of bird flu, when it go, if it goes pandemic on us, it's not going to be that deadly. And, you know, it's so that we don't have our scare hats on. We do know that from history, viruses tend to become less deadly as they go pandemic, because it allows them to spread.

• 38:54Wendy Zukerman?

  But it also could be that this bird flu isn't that deadly for everyone, but it still has a high case fatality rate.

• 39:03Speaker 02

  Mm-hmm.

• 39:04Wendy Zukerman?

  This is just where we're at. It's just like this tip of who knows what. And in the meantime, we can't trust that we're getting proper information about

• 39:13Speaker 02

  Right.

• 39:14Wendy Zukerman?

  what's actually going on.

• 39:15Speaker 02

  That's, yeah, that's my feeling in this moment. And I guess I will say, like, not to, to

• 39:19Wendy Zukerman?

  Not to put your scare hat on.

• 39:21Speaker 02

  Not to put my scare hat on. I will say, you know, I will say, like, not to, I don't want to be alarmist about it, right? Because I will also say that, like, I asked a bunch of scientists this question because I've had this question. I'm like, if there is, if things, if this thing really starts to spread, will we know?

• 39:37Wendy Zukerman?

  Mm.

• 39:37Speaker 02

  And all of them were like, yeah, dude. Like, if this really gets going, like, and we're seeing a lot of cases, they're like, we'll know. You know, like, reports are gonna come out other ways. There's gonna be, you know, you're gonna start hearing from doctors.

• 39:52Wendy Zukerman?

  Yeah.

• 39:55Wendy Zukerman?

  Okay, so then, you know, we mentioned the boy who cried wolf at the start of the show. So is it, are we, are we crying wolf?

• 40:09Speaker 02

  Well, now you have me worried, Wendy. We all know what happened to that guy. He was murdered by wolves.

• 40:15Wendy Zukerman?

  Yeah, I forget the ending of that. It's funny that, isn't it?

• 40:18Speaker 02

  So stop trying to trap me into.

• 40:23Wendy Zukerman?

  Watch this space. Blythe will be there on the top of the hill, looking for the wolves.

• 40:28Speaker 02

  Yeah. I've got my binoculars. I'm, I'm gonna do my best to keep watch for the wolves.

• 40:34Wendy Zukerman?

  All right. In the meantime, watch out if you get pink eye.

• 40:38Speaker 02

  That's right.

• 40:39Wendy Zukerman?

  Thanks, Blythe. Um, how many citations are in this week's episode?

• 40:43Speaker 02

  Um, so in this week's episode, we have 123 citations, Wendy.

• 40:52Wendy Zukerman?

  Ooh.

• 40:53Speaker 02

  I know.

• 40:54Wendy Zukerman?

  All right. And if people want to read more about bird flu, where should they go?

• 40:58Speaker 02

  They should go to our transcript, which they can find in the show notes of this episode. And they can find all of our sourcing, including, by the way, some citations that I'm sure will explain that a virus is not necessarily technically alive. It's complicated, we know.

• 41:16Wendy Zukerman?

  Yes, yes. Also, next week, you know, we did allude to the fact that there have been cuts to science funding, which we have talked about on the show before. But next week, we're going to do an update on what exactly is going on with US science right now.

• 41:34Speaker 02

  Yeah.

• 41:35Wendy Zukerman?

  There's been a lot. There's been a lot happening.

• 41:37Speaker 02

  A lot happening. And also, like, to point out, too, you know, we talk about layoffs. We talk about some people losing their jobs. There have been stories about the government trying to rehire some of those people, some of the people working on bird flu. It's just been really confusing what's actually going on with that. And I just want to note, too, that I did reach out to Health and Human Services and talk to them about a little bit of this. I did try to ask them about this whole idea that we might be missing cases of bird flu. And I just, I didn't hear back on that.

• 42:06Wendy Zukerman?

  Mm hmm. All right. Thanks, Blythe.

• 42:08Speaker 02

  Thank you, Wendy. Thanks for letting me bird flu with you.

• 42:13Wendy Zukerman?

  Thanks for bird fluing with me. Anytime.

• 42:23Wendy Zukerman?

  This episode was produced by Blythe Terrell with help from me, Wendy Zukerman, Michelle Dang, Rose Rimler, Merrill Horn, and Akety Foster Keys. We're edited by Blythe Terrell. Mix and sound design by Bobby Lord and Sam Vair. Fact checking by Erica Akiko Howard. Music written by Boomi Hidaka, Peter Leonard, Emma Munga, So Wiley, and Bobby Lord. Thanks so much to all of the researchers that we spoke to for this episode, including Dr. Louise Moncla, Dr. Ted Elsasser, Dr. John Korslund, Victoria Rosado, and Lindsay Adams. A special thanks to Jeff Del Visio. Science Versus is a Spotify Studios original. Listen to us for free on Spotify or wherever you get your podcasts. We are everywhere. Whatever you listen to us on, give us a five star review because it helps people find

• 43:07Wendy Zukerman?

  the show. And if you are listening on Spotify, follow us and tap the bell icon so you get notifications when new episodes come out. And if you would like to get in touch with us, we are on Instagram, science underscore VS. I'm on TikTok, at Wendy Zukerman. So come and say hello. I'm Wendy Zukerman. Back to you next time.

• 43:36Speaker 13

  Get your business ready for clients faster with Base44. Describe what you need in your own words and build the website and software behind it with database, backend, and hosting included. Go to base44.com. That's base44.com.