Bird Flu: The Next Pandemic?

Summary

Science Vs: Bird Flu—The Next Pandemic?

Episode Release Date: May 15, 2025
Host: Wendy Zuckerman
Editor: Blythe Terrell
Description: In this gripping episode, Science Vs delves deep into the escalating bird flu crisis, examining its impact across various species and the looming threat it poses to human populations. Through expert insights and thorough analysis, the episode sifts through the facts to determine whether bird flu could indeed spark the next global pandemic.

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1. Introduction to the Bird Flu Crisis

The episode opens with Wendy Zuckerman and editor Blythe Terrell setting the stage for a critical discussion on bird flu. Blythe expresses her frustration over the recurring warnings about bird flu over the past decades, questioning whether the persistent alarm is indicative of escalating danger or another case of "the boy who cried wolf."

Notable Quote:
Wendy Zuckerman [00:49]:
"Has something changed?"

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2. The Escalation of Bird Flu Among Birds and Poultry

Blythe Terrell explains that recent months have seen an unprecedented outbreak of bird flu in the United States, marking the largest in the country’s history. Since 2022, over 135 million birds have been affected, leading to skyrocketing egg prices and widespread scarcity reminiscent of pandemic-era shortages.

Key Points:

• Massive die-offs in poultry farms.
• Surge in egg prices, referred to as "eggflation."
• Instances of egg smuggling due to scarcity.

Notable Quote:
Seema Lakhdawala [01:26]:
"The biggest outbreak of bird flu in US History is sweeping across this country, leaving millions of hens dead."
Blythe Terrell [01:33]:
"Eggflation is back with a vengeance, and it's cooking the family's grocery budget."

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3. Spread to Wild and Domestic Mammals

The bird flu outbreak has transcended avian species, with the virus now detected in various mammals including foxes, raccoons, skunks, domestic cats, seals, and cattle. This cross-species transmission raises significant concerns about the virus mutating and adapting to new hosts.

Key Points:

• Seals: Initial infections traced to shoreline interactions with infected birds.
• Cattle: First human cases linked to transmission from cattle, a novel development.
• Other Mammals: Continuous spread in diverse animal populations.

Notable Quote:
Blythe Terrell [02:29]:
"The global spread in animals has been unprecedented, according to the UN."

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4. Human Infections and Symptoms

Human cases of the novel H5N1 bird flu variant began emerging in March 2024, primarily linked to contact with infected cattle and birds. Unlike previous strains, most human infections exhibit milder symptoms, though a few severe cases have resulted in hospitalization and death.

Key Points:

• Approximately 70 known cases in the US as of early 2025.
• Predominant symptoms include fatigue and respiratory issues, with an unusual prevalence of conjunctivitis (93% of cases).
• Severe cases in Canada and Louisiana highlight the virus's potential lethality.

Notable Quotes:
Seema Lakhdawala [07:58]:
"Bird flu can cause severe respiratory failure and organ damage."
Blythe Terrell [22:06]:
"Despite scary headlines, most US cases present milder symptoms, but some have been critical."

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5. Mutation and Pandemic Potential

Experts discuss the virus's capacity to mutate, increasing its transmissibility among humans. Richard Webby emphasizes that while the current strain retains its avian characteristics, minimal mutations could render it highly contagious among humans. The phenomenon of reassortment—where bird flu combines with human flu strains—poses a significant risk for a pandemic.

Key Points:

• Flu viruses, including H5N1, are prone to mutations.
• Laboratory studies indicate that a single mutation could enhance human-to-human transmission.
• Reassortment events could accelerate the virus’s adaptation to human hosts.

Notable Quote:
Richard Webby [28:20]:
"The virus could be one mutation away from spreading easily among humans."

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6. Government Response and Public Health Measures

The response to the bird flu outbreak has been criticized as inadequate, particularly following reductions in funding and personnel within public health agencies under the Trump administration. The USDA focuses on controlling outbreaks in poultry but has been less aggressive with cattle, despite the emerging threat.

Key Points:

• Inconsistent tracking and reporting of human cases raise concerns about potential underestimation.
• Limited availability of bird flu vaccines, with existing ones not yet optimized for mass human use.
• Health and Human Services prioritizing seasonal flu vaccines for agricultural workers as a preventive measure.

Notable Quote:
Blythe Terrell [34:53]:
"We're still at around 70 human cases two months after the jump, which is suspicious given ongoing animal outbreaks."

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7. Public Awareness and Preventative Actions

While vaccines and antivirals exist, their efficacy against the current bird flu strain remains uncertain. Public health experts encourage vaccination against seasonal flu to reduce the risk of reassortment. Additionally, avoiding raw milk and unpasteurized products is advised to prevent direct transmission from infected animals.

Key Points:

• Importance of following pasteurization protocols to eliminate the virus in dairy products.
• Keeping raw milk and unpasteurized cheese out of consumption to avoid infection.
• Use of masks recommended as a general preventive measure against respiratory viruses.

Notable Quote:
Blythe Terrell [16:45]:
"Do not drink raw milk right now. You could be straight up drinking bird flu."

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8. Silent Spread and Undocumented Cases

A CDC report revealed that several veterinarians exhibited antibodies against H5N1 without showing symptoms, suggesting asymptomatic or mild infections that might go unreported. This underlines the difficulty in accurately gauging the virus's true prevalence and potential for unnoticed transmission.

Key Points:

• Presence of antibodies in vaccinated individuals indicates possible silent spread.
• Difficulty in tracking asymptomatic cases complicates outbreak control.
• Raises questions about the virus’s actual case fatality rate and transmission dynamics.

Notable Quote:
Blythe Terrell [36:57]:
"Three veterinarians had antibodies for H5N1, some without knowing they were exposed. This suggests silent spread."

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9. Expert Perspectives and Future Outlook

Experts like Richard Webby and Seema Lakhdawala share their cautious optimism and concern. While some believe the virus may not become a human pathogen, others warn that continued exposure increases the chances of dangerous mutations. The consensus emphasizes proactive monitoring and preparedness to prevent a full-scale pandemic.

Key Points:

• Ongoing vigilance is crucial as the virus continues to circulate in multiple species.
• Importance of robust surveillance systems to detect and respond to emerging mutations.
• Balancing optimism with caution to avoid complacency in public health measures.

Notable Quotes:
Seema Lakhdawala [32:13]:
"What we're allowing this virus to do is take thousands of chances to mutate."
Richard Webby [30:02]:
"The barrier to key changes is relatively high, but not insurmountable."

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10. Conclusion: Are We Facing a New Pandemic?

As the episode wraps up, Blythe Terrell and Wendy Zuckerman grapple with the uncertain trajectory of the bird flu. While current human cases are manageable, the potential for the virus to mutate and transmit efficiently between humans remains a significant threat. The dialogue underscores the necessity for increased scientific funding, transparent reporting, and public awareness to mitigate the risks of a looming pandemic.

Final Thoughts:
The ongoing bird flu outbreak serves as a stark reminder of the delicate balance between animal and human health. Without decisive action and comprehensive monitoring, the threat of a new pandemic becomes increasingly plausible.

Notable Quote:
Blythe Terrell [38:48]:
"If this really gets going, like, you'll start seeing lots of cases. We’ll know."

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Further Resources:
For those interested in diving deeper, the episode's transcript and comprehensive citations are available in the show notes. Upcoming episodes will continue to explore related topics, including updates on science funding and governmental responses.

Stay Informed:
Follow Science Vs on Spotify, Instagram (@sciencevs), and TikTok (@WendyZuckerman) for the latest updates and detailed analyses on pressing scientific issues.

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Disclaimer: The information presented in this summary is based on the transcript provided and aims to accurately reflect the content and discussions from the Science Vs episode on bird flu. Always consult professional health sources for medical advice and updates.

Transcript

[Wendy Zuckerman]

Hi, I'm Wendy Zuckerman, and you're listening to Science Verses. Today on the show, we are pitting facts against bird flu. And to tell us all about it is editor of Science versus Blythe Terrell. Hey, Blythe.

[Blythe Terrell]

Yeah. Hey, Wendy.

[Wendy Zuckerman]

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 my day.

[Blythe Terrell]

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

[Wendy Zuckerman]

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

[Seema Lakhdawala]

I will.

[Blythe Terrell]

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

[Wendy Zuckerman]

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?

[Blythe Terrell]

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, like, poultry farms being hit super, super hard.

[Seema Lakhdawala]

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

[Blythe Terrell]

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. Eggflation is back with a vengeance, and it's cooking the family's grocery budget.

[Richard Webby]

Are they going up more? Are all the birds gonna die?

[Blythe Terrell]

Wendy, I have seen reports of eggs smuggling. Like, people getting busted bringing eg. Also, like, in. In New York City, in the Bronx, the bodegas are like, 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.

[Wendy Zuckerman]

Time in Australia, too. Eggs 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.

[Blythe Terrell]

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.

[Wendy Zuckerman]

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

[Richard Webby]

Many health experts are calling this a.

[Blythe Terrell]

Global pandemic of animals. The UN has called the spread in animals, quote, unprecedented, actually.

[Wendy Zuckerman]

Mm.

[Blythe Terrell]

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 U.S. right. 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.

[Richard Webby]

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

[Wendy Zuckerman]

When we say we are in emergency mode, that is the mode we are.

[Blythe Terrell]

In right now could potentially lead to another pandemic.

[Wendy Zuckerman]

Oh, man, are they right.

[Blythe Terrell]

That's what we're going to find out after the break.

[Wendy Zuckerman]

This episode is brought to you by Brooks. So Brooks just released the new Glycerin 22 running shoes. And let me tell you why. I think you're going to love them. So I have weird shaped feet. I know lots of people don't love their feet, but seriously, I have bunions on one side of my foot. On the other side, there's this bone that may as well be a bunion. The pinky toe is weird. The second toe, it's all just a mess. And it means that buying shoes is a real mess. Every single time I buy shoes, and particularly running shoes, I have to coat my feet with band aids so I don't get blisters. Except for when I wear Brooks. Seriously, I just put on my new glycerin 22 running shoes just then and went for a run. No band aids. And my feet feel great. It was a great run. They were bouncy. It was fun. They're also so bright. They're so clean. I guess that's just because they're new shoes. But seriously, I'm really excited about these shoes. If you want to know more about the glycerin 22 shoe, head to BrooksRunning.com this episode is brought to you by. Indeed. Taking things slow isn't always a good thing. Sometimes you need to speed things along. Like when your toilet breaks down. You gotta get that plumber in quickly or you're gonna be in trouble. If you're hiring, you probably also wanna get things moving fast. So use Indeed. Indeed. Sponsored Jobs. Move your job post to the top of the page. Helping you stand out and reach candidates quickly speed up your H. Hiring right now with a 75 sponsored job credit at indeed.comscienceon that's indeed.comscienceon terms and conditions apply. Hiring indeed is all you need. Welcome back. Today we're talking about bird flu. Blythe is about to tell us if this is going to be the next pandemic.

[Blythe Terrell]

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

[Wendy Zuckerman]

Okay.

[Blythe Terrell]

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 a hundred million people.

[Wendy Zuckerman]

Why do they think that?

[Blythe Terrell]

Yeah, so there's a couple 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 a thousand people have been diagnosed with this H5N1, and about half of them have died.

[Wendy Zuckerman]

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

[Blythe Terrell]

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 can be really bad.

[Wendy Zuckerman]

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?

[Blythe Terrell]

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.

[Wendy Zuckerman]

2344B it's called. I didn't realize that when they started calling those coronavirus variants Delta and Omicron that they were being all fancy with us.

[Blythe Terrell]

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.

[Wendy Zuckerman]

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

[Blythe Terrell]

Yeah. Mm. 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.

[Wendy Zuckerman]

Okay.

[Blythe Terrell]

I talked about this with Seema Lakhdawala, 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.

[Seema Lakhdawala]

The U.K. i would say 2021, where, like, birds were just falling out of the sky dead.

[Blythe Terrell]

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

[Seema Lakhdawala]

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

[Blythe Terrell]

I actually watched a video of this bald eagle with bird flu, and it's, like, flying down to the ground, and then 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. Oh, gosh, that's really sad.

[Wendy Zuckerman]

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

[Blythe Terrell]

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 U.S. and we start seeing it in wild birds and in chickens. And this is, like, late 2021, 2022.

[Wendy Zuckerman]

Okay.

[Blythe Terrell]

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.

[Wendy Zuckerman]

Right?

[Blythe Terrell]

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 and birds, right? But then this virus starts showing up in, like, more and more mammals. And scientists always keep an eye on that, because 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.

[Wendy Zuckerman]

Human to human, which, at this point, hasn't really happened.

[Blythe Terrell]

Right. But here is Sima.

[Seema Lakhdawala]

Every time a virus, like a bird virus gets into a mammal, it can then adapt to that mammal.

[Blythe Terrell]

Right?

[Seema Lakhdawala]

Cause viruses change. Know this Covid, right? Omicron delta. Like, I'm you know, I'm saying things that people remember. Viruses change when they infect hosts.

[Wendy Zuckerman]

Uh huh. Okay.

[Blythe Terrell]

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.

[Seema Lakhdawala]

We've had sporadic spillover events from birds into seals in lots of different places. Right. You might remember this.

[Wendy Zuckerman]

Seal outbreaks. Oh, yeah. And so this is 2022.

[Blythe Terrell]

We're at 2022. 23.

[Wendy Zuckerman]

Okay. Yeah. How did the seals get it?

[Blythe Terrell]

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. Pooh.

[Wendy Zuckerman]

I thought was the crab. Those birds crap so much and so they're crapping out the virus.

[Blythe Terrell]

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

[Wendy Zuckerman]

Oh.

[Blythe Terrell]

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.

[Seema Lakhdawala]

It's not terrifying yet.

[Blythe Terrell]

Okay.

[Wendy Zuckerman]

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.

[Blythe Terrell]

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 for people like Seema?

[Seema Lakhdawala]

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

[Wendy Zuckerman]

Cat. Cattle. Oh, I'm so sure she was gonna say human. So why? I mean, cows just feel like seals of the land. Why is she worried about Cattle, I.

[Blythe Terrell]

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

[Wendy Zuckerman]

So you got those big eyes, you know? Sure.

[Blythe Terrell]

Charismatic megafauna.

[Wendy Zuckerman]

Yes.

[Blythe Terrell]

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

[Seema Lakhdawala]

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

[Blythe Terrell]

Compared to, say, seals, she's like, cattle. 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.

[Wendy Zuckerman]

Okay.

[Blythe Terrell]

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. So this bird flu belongs to this group of flus known as influenza A's, 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. To think that a cow could get this kind of flu.

[Wendy Zuckerman]

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

[Blythe Terrell]

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. 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.

[Seema Lakhdawala]

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.

[Blythe Terrell]

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.

[Wendy Zuckerman]

Right.

[Blythe Terrell]

And they were, like, pretty confused.

[Seema Lakhdawala]

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.

[Blythe Terrell]

Whoa. This is like, House. This is, like. Yeah.

[Seema Lakhdawala]

Like, right. It's super.

[Blythe Terrell]

Like, again, detective work.

[Seema Lakhdawala]

Right.

[Blythe Terrell]

And then, of course, they work out.

[Wendy Zuckerman]

That it's bird flu and the bird flu was giving the cat neurological symptoms. And the cows mastitis.

[Blythe Terrell]

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, and what.

[Seema Lakhdawala]

They found was, like, massive amounts of virus in the milk. And when I talk about massive amounts, 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 1 milliliter. 1 milliliter of milk.

[Wendy Zuckerman]

Oh, gosh. Was the virus alive? I mean, are we drinking that virus?

[Blythe Terrell]

The virus that is actually in the milk is alive. Are we drinking it? If you are drinking pasteurized milk.

[Wendy Zuckerman]

Right.

[Blythe Terrell]

Pasteurization does seem to kill the virus.

[Wendy Zuckerman]

Okay.

[Blythe Terrell]

From everything I 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.

[Wendy Zuckerman]

Right.

[Blythe Terrell]

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

[Wendy Zuckerman]

Yes.

[Blythe Terrell]

Which is the whole point of it is it's not pasteurized.

[Wendy Zuckerman]

Right, right.

[Blythe Terrell]

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.

[Wendy Zuckerman]

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

[Blythe Terrell]

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

[Wendy Zuckerman]

Take it away. Yeah.

[Blythe Terrell]

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

[Wendy Zuckerman]

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

[Blythe Terrell]

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

[Wendy Zuckerman]

Aha. Don't be guest. Stunning in this moment.

[Blythe Terrell]

Oh, my God.

[Wendy Zuckerman]

Five dozen eggs. Don't do it.

[Blythe Terrell]

Right. Don't gaston your way to getting bird flu, please. The other thing that I would just want to point out is that it's showing up in cows, and we are, like, really not doing all that much to stop it. Like, definitely not to the level of what we do with other animals. Chickens.

[Wendy Zuckerman]

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

[Blythe Terrell]

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.

[Wendy Zuckerman]

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.

[Blythe Terrell]

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

[Wendy Zuckerman]

Oh, gosh.

[Blythe Terrell]

So it's so far been found in more than a thousand herds of cows in 17 states in the US and I will tell you one more thing, Wendy.

[Seema Lakhdawala]

Oh, yeah.

[Blythe Terrell]

So this is.

[Seema Lakhdawala]

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

[Blythe Terrell]

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.

[Wendy Zuckerman]

Yeah.

[Blythe Terrell]

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

[Wendy Zuckerman]

Oh, sounds like a 90s band.

[Blythe Terrell]

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

[Seema Lakhdawala]

When a cow is sick, it ha. Like, say with age 5 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 chunkety milk. Right. This mastitis milk. So it does 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.

[Wendy Zuckerman]

Oh, no.

[Seema Lakhdawala]

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 in 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 in which we think that peri. Domestic animals on farms, near farms are getting infected. Right. Because it's just in the environment.

[Wendy Zuckerman]

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

[Blythe Terrell]

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

[Wendy Zuckerman]

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 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?

[Blythe Terrell]

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

[Wendy Zuckerman]

Coming up.

[Susan Ettlinger]

The PC gave us computing power at home. The Internet connected us and mobile let us do it pretty much anywhere. Now, generative AI lets us communicate with technology in our own language, using our own senses. But figuring it all out when you're living through it is a totally different story. Welcome to Leading the Shift, a new podcast for Microsoft Azure. I'm your host, Susan Ettlinger. In each episode, leaders will share what they're learning to help you navigate all this change with confidence. Please join us, listen, and subscribe wherever you get your podcasts.

[Wendy Zuckerman]

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

[Blythe Terrell]

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

[Wendy Zuckerman]

Yes.

[Blythe Terrell]

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

[Wendy Zuckerman]

The US and they're now getting that newish version that H5N1 baby that you were talking about.

[Blythe Terrell]

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.

[Wendy Zuckerman]

Oh. Cause we normally get it through the birds, right?

[Blythe Terrell]

Right. Yeah, we normally get it directly from a bird.

[Wendy Zuckerman]

Okay.

[Blythe Terrell]

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

[Wendy Zuckerman]

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

[Blythe Terrell]

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.

[Wendy Zuckerman]

Oh.

[Blythe Terrell]

We are mostly seeing people who have fluy 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.

[Wendy Zuckerman]

No, that is. That is strange.

[Blythe Terrell]

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

[Wendy Zuckerman]

Good news. Great news. There.

[Blythe Terrell]

But then there are some serious cases where things played out really differently. And I want to talk about a couple of those. Okay, so there's one in Canada. Canada's first human case of bird flu has everyone talking about. Canadian teenager with the virus has been actually hospitalized in critical condition. Had to be on life saving 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.

[Seema Lakhdawala]

For the first time bird flu has claimed a human life in the US.

[Wendy Zuckerman]

The first person to die of bird flu. It's alarming.

[Blythe Terrell]

That's right. Because this feels like it was a.

[Seema Lakhdawala]

Threshold, an alarm bell sounding.

[Blythe Terrell]

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 age 5N1'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.

[Wendy Zuckerman]

Oh, no.

[Blythe Terrell]

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.

[Wendy Zuckerman]

Mm. 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?

[Blythe Terrell]

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.

[Wendy Zuckerman]

Yes.

[Blythe Terrell]

And we start freaking out about a pandemic.

[Wendy Zuckerman]

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

[Blythe Terrell]

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

[Seema Lakhdawala]

Has been no documented human to human transmission. Does that mean it hasn't happened?

[Wendy Zuckerman]

No.

[Blythe Terrell]

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

[Wendy Zuckerman]

Right. Okay. 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?

[Blythe Terrell]

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.

[Wendy Zuckerman]

Yes.

[Blythe Terrell]

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?

[Richard Webby]

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

[Wendy Zuckerman]

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

[Blythe Terrell]

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

[Wendy Zuckerman]

Oh, okay.

[Blythe Terrell]

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.

[Wendy Zuckerman]

Right. So they can then infect seals and cows and other animals.

[Blythe Terrell]

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? Yeah, I. I know you're shaking your head.

[Richard Webby]

Yeah, you can see.

[Blythe Terrell]

You love this question.

[Wendy Zuckerman]

I just love it. I love it.

[Richard Webby]

I love it a lot. Right. What is the. So I'll tell you why I find that difficult to answer if we look today. So right now, today, even, let's look at the virus that's in cows. Even the viruses that we get from people that have been infected, they still have all of the characteristics of bird viruses. They want to be infecting birds.

[Blythe Terrell]

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.

[Wendy Zuckerman]

Got it.

[Blythe Terrell]

Got it. Generally got it. Which is good news.

[Richard Webby]

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

[Wendy Zuckerman]

Yes.

[Blythe Terrell]

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. Probably be easier to get into people. 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?

[Wendy Zuckerman]

Yeah, yeah.

[Blythe Terrell]

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 did have mutations that might have made it it easier to spread from person to person.

[Wendy Zuckerman]

Wow.

[Blythe Terrell]

Which is interesting because it didn't in those cases.

[Wendy Zuckerman]

Yes. Right.

[Blythe Terrell]

Which brings me to perhaps, like a kind of surprisingly optimistic point. Some good news, if you'll have it.

[Wendy Zuckerman]

I'll take it. I'll take some good news.

[Blythe Terrell]

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, like, scientists are, like, really debating what that means.

[Richard Webby]

So some people look at that, you know, even some experts look at that and say H5 can never become a human pathogen. And that's really.

[Blythe Terrell]

They say it never can.

[Richard Webby]

That's right. That's just not able to do it. Right.

[Blythe Terrell]

It would have. They say it would have happened by now if it could.

[Richard Webby]

Right.

[Blythe Terrell]

Huh?

[Richard Webby]

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.

[Wendy Zuckerman]

Mm. Yeah. That's interesting. And that's not really a gamble we want to make.

[Blythe Terrell]

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 like, 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 like, 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 like that process has triggered, one scientist told me, basically all the major flu pandemics in modern history. Oh.

[Wendy Zuckerman]

Where a human flu or a human adapted flu basically has virus sex with an. 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 beep beep, beep, beep, beep. I'll take this. And now we can infect humans. Much easier than having to completely develop.

[Blythe Terrell]

All these rinky dink mutation by mutation by mutation by mutation. So that's another thing that they're really watching for.

[Wendy Zuckerman]

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

[Blythe Terrell]

I know it is, isn't it? On science versus, I mean an 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.

[Wendy Zuckerman]

Yeah.

[Blythe Terrell]

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

[Seema Lakhdawala]

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

[Blythe Terrell]

When would you worry?

[Seema Lakhdawala]

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

[Blythe Terrell]

Given all of this. Right. I asked Richard, let's see, where is Dr. Richard Webby's worry meter?

[Richard Webby]

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.

[Blythe Terrell]

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

[Richard Webby]

I think that'll be the key. If my neighbours 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.

[Wendy Zuckerman]

You mentioned buying a few extra masks. That would that help?

[Blythe Terrell]

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

[Wendy Zuckerman]

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

[Blythe Terrell]

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

[Wendy Zuckerman]

Oh, okay. But extra toilet paper, did you do that yet?

[Blythe Terrell]

No, still taking my chances on that one.

[Wendy Zuckerman]

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

[Blythe Terrell]

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

[Wendy Zuckerman]

Great.

[Blythe Terrell]

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

[Richard Webby]

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

[Blythe Terrell]

And we have stuff like antivirals that can help too.

[Wendy Zuckerman]

It's funny because I have to, I 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?

[Blythe Terrell]

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. I mean that's 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, 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.

[Wendy Zuckerman]

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

[Blythe Terrell]

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 who are job. It was to work on diseases like this, right? 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, 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 taking 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?

[Wendy Zuckerman]

Yeah, yeah, yeah.

[Blythe Terrell]

And so where we are now, it's May more than two months later and we're still like supposedly at 70 cases. 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've been almost 50 new cattle herds infected in just the past month.

[Wendy Zuckerman]

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

[Blythe Terrell]

Yeah. So are we really not getting more cases in people? It's just so hard to know if we can trust that. That is scary. Yeah. And there is one more thing, you know, that, that I guess gets my spidey sense on this tingling. So there was this CDC report out a couple 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?

[Wendy Zuckerman]

Uh huh.

[Blythe Terrell]

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

[Wendy Zuckerman]

Okay.

[Blythe Terrell]

Yeah. But they hadn't really been sick. And in some cases, 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.

[Wendy Zuckerman]

Oh gosh. What does this tell us? What does this tell us? Because it means they didn't even know they were sick. 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 gonna be that deadly. And you know, 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. But it also could be that this bird flu isn't that deadly for everyone, but it still has a high case fatality rate. 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 what's actually going on.

[Blythe Terrell]

That's. Yeah, that's my feeling in this moment. And I guess I will say, like, not to. Not to put your scare hat on. 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? 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.

[Wendy Zuckerman]

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

[Blythe Terrell]

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

[Wendy Zuckerman]

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

[Blythe Terrell]

So stop trying to trap me into.

[Wendy Zuckerman]

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

[Blythe Terrell]

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

[Wendy Zuckerman]

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

[Blythe Terrell]

That's right.

[Wendy Zuckerman]

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

[Blythe Terrell]

So in this week's episode, we have 123 citations. Wendy. Ooh, Hello.

[Wendy Zuckerman]

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

[Blythe Terrell]

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.

[Wendy Zuckerman]

Yes, yes. Also next week, you know, we. 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 gonna do an update on what exactly is going on with us science. Cause there's been a lot. There's been a lot happening.

[Blythe Terrell]

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 wanna 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.

[Wendy Zuckerman]

All right, thanks, Blythe.

[Blythe Terrell]

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

[Wendy Zuckerman]

Thanks for bird fluing with me.

[Blythe Terrell]

Anytime.

[Wendy Zuckerman]

This episode was produced by Blythe Terrell, with help from me, Wendy Zuckerman, Michelle Dang, Rose Rimler, Meryl Horn and Aketti Foster. Keys we're edited by Blythe Terrell Mix and sound design by Bobby Lord and Sam Baer Fact checking by Erica Akiko Howard Music written by Bumi Hidaka, Peter Leonard, Emma Munger so Wiley and Bobby Lord. Thanks so much to all of the researchers that we spoke to for this episode including Dr. Louise Moncler, Dr. Ted Elsasser, Dr. John Corsland, Victoria Rosado and Lindsey Adams. A special thanks to Jeff Dalvisio. Science Versus is a Spotify Studios original. Listen to 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 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 sciencevs. I'm on TikTok Wendy Zuckerman so come and say hello, I'm Wendy Zuckerman. Back to you next time.