In This Episode
Why does it feel like avian flu is always circling around? How did it land on cows? Are we on the cusp of another pandemic? Dr. Abdul El-Sayed, host of America Dissected, joins Erin to break down how this strain of bird flu could go from animal plague to human plague, lessons learned from past outbreaks, and what can be done to stop it this time around.
SOURCES
A Bird Flu H5N1 Status Report – by Eric Topol
Updates on Highly Pathogenic Avian Influenza (HPAI) | FDA
H5N1 update: We have to do better, faster
Bird flu ‘an urgent warning to move away from factory farming’
Inflation is cooling. Why are egg prices still so hard to crack?
Birds, Pigs, and People: The Rise of Pandemic Flus – PMC
The cost of replication fidelity in an RNA virus.
‘Nobody saw this coming’; California dairies scramble to guard herds against bird flu
H5N1 Bird Flu: Current Situation Summary | Avian Influenza (Flu)
Bird flu risk prompts warnings against raw milk, unpasteurized dairy products – CBS News
Climate change will force new animal encounters — and boost viral outbreaks.
TRANSCRIPT
Erin Ryan: Abdul, do you ever feel like you’re living in a time loop?
Abdul El-Sayed: Yeah, sometimes. But then I look in the mirror and despite my incredible skin routine, I realize that I am, in fact, getting older.
Erin Ryan: I’m serious. Just look at the similarities between 2020 and 2024, both leap years. Joe Biden and Donald Trump are the two major party nominees for president. The Chiefs beat the 49ers in the Super Bowl both times. And once again, we’re here talking about a pandemic.
Abdul El-Sayed: Yeah, you’re probably talking about that uh H5n1 avian flu that has recently been found in dairy cows across nine states.
[clip of unidentified news reporter number 1] The US FDA says that samples of milk taken from grocery stores across the US have tested positive for remnants of the bird flu virus that has infected dairy cows.
[clip of unidentified news reporter number 2] America’s dairy cows will be tested for bird flu more closely to stop the virus from spreading.
[clip of unidentified news reporter number 3] Starting Monday, all dairy cattle moving between states must be tested for bird flu.
Erin Ryan: Yeah, I feel like all of a sudden, bird flu infected cows are like this horror movie monster creeping toward us in plain sight, and we are doomed to repeat the worst parts of 2020 all over again.
Abdul El-Sayed: I mean, we’ve been farming cows and chickens for long enough that you knew they were going to team up to get back at us. [laughter] So look, we’re not necessarily doomed to repeat 2020. First of all, the Lakers. Well, they’ve already been eliminated from the NBA playoffs. So there’s that. And um secondly, there are a ton of differences between the early days of the Covid pandemic and what we’re seeing now with the avian flu.
Erin Ryan: Oh thank goodness. So you’re going to tell me a bunch of stuff about bird flu infected livestock. And it’s going to make me feel better.
Abdul El-Sayed: Yeah. No, that’s not happening.
Erin Ryan: Oh.
Abdul El-Sayed: Not at all.
Erin Ryan: Oh okay.
Abdul El-Sayed: But I can help you to put your pandemic anxiety at least and we’ll just say, put it in the right box and tie a little bow over it. How about that?
Erin Ryan: Oh. Okay, well thank you. I think.
Abdul El-Sayed: I’m Dr. Abdul Azad, host of America Dissected.
Erin Ryan: I’m Erin Ryan.
Abdul El-Sayed: And this is How We Got Here. The show where we take one big question from the week’s news and tell a story that answers that question.
Erin Ryan: This week, what will it take for the H5n1 bird flu strain to go from animal plague to human plague? And what, if anything, can be done to stop it?
Abdul El-Sayed: Considering that I literally spend my day job working on this problem, I do have to try and chop this up a little bit. So to even begin to answer this, we’re going to tell the story of a couple of outbreaks that graduated from animal illness to human pandemic and break down what would need to happen for this strain of bird flu to become a five alarm, shut it all down, worst case scenario. A recipe for public health disaster, if you will.
Erin Ryan: A recipe for public health disaster. The lowest rated recipe on the New York Times cooking app.
Abdul El-Sayed: But the good news is this one does it come with a long preamble about the chef’s life. How about that?
Erin Ryan: [laughter] Classic public health official humor right there. Okay, so right off the bat, you’re helping assuage my fears. You’re saying that this H5n1 virus that has been running roughshod through cattle in nine states is not currently a nightmare scenario.
Abdul El-Sayed: It could get there if some of the elements line up just right. We think about a virus’s pandemic potential in three ways, transmissibility, pathogenicity, and immune evasion. And I know those are big words. So let me break it down. Transmissibility is how likely this is to transmit between people. It’s basically a function of how sticky that is. Remember our discussion of the SARS-CoV-2 spike protein? You know that spike on the coronavirus, that was what made the Covid virus so sticky. It could bind our cells well and therefore infect them.
Erin Ryan: Okay, so like throwing a ball of glue at something versus, say, throwing a ping pong ball.
Abdul El-Sayed: That’s exactly right. And when it comes to pathogenicity, again, another one of those words, it just means how sick it makes us. A pandemic capable virus isn’t too pathogenic because think about it, if it killed everybody really quickly, it would burn out. And if it’s not pathogenic enough, then we don’t really care about it because it doesn’t make us that sick, think the common cold.
Erin Ryan: Okay, I got it.
Abdul El-Sayed: And then finally, immune evasion, the ability to rapidly evolve to evade our immune systems. In this case, you’re usually talking about a virus whose genetic code is mediated through RNA, the material our bodies use to take, we’ll call them notes, of what our DNA says. Those notes have a lot of mistakes in them. And those mistakes, well, they usually kill viruses.
Erin Ryan: Oh my gosh, I can feel the anxiety leaving my body.
Abdul El-Sayed: Not so fast.
Erin Ryan: Oh.
Abdul El-Sayed: Sometimes they make viruses even better at infecting us.
Erin Ryan: Okay. Never mind anxiety is back.
Abdul El-Sayed: So over time, our bodies build up immunity. What happens is the viruses that survive, they’re the ones with the mutations that can allow them to evade our immune response. And so what happens is our immunity actually selects for those mutations that make those viruses better able to transmit between us. That’s why, for example, we keep having new waves of Covid caused by new variants that figure out how to evade our immunity and identify the nooks and crannies in our immune response.
Erin Ryan: All right, so now we know the story of what could take John or Jane every germ to the big leagues. But we also have examples from history about external conditions beyond the nature of the viruses themselves that lent themselves well to mutation and spread. Right. Like you can lock the nastiest, stickiest germ in the world in a janitor closet. And if it can’t find anything to infect, it’s just going to die there, right?
Abdul El-Sayed: That’s exactly right. In order for H5n1 to become the next pandemic, it would certainly be helped along by the ability to spread quickly and over long distances.
Erin Ryan: Like a viral mass transit system.
Abdul El-Sayed: So for a historical example of that, we can look to the 1918 influenza pandemic, which was aided and abetted in a big way by what was going on in 1918, World War one.
Erin Ryan: Okay, so can you explain how World War One helped the influenza pandemic along?
Abdul El-Sayed: Yeah, contrary to the Spanish flu misnomer, the H1n1 flu virus that killed tens of millions between 1918 and 1920 actually was first documented in Camp Funston in Kansas.
Erin Ryan: Ah. USA. Number one, take that Spain.
Abdul El-Sayed: Trying to put their names on things that we created. Early in 1918, doctors at the military base noticed that the flu cases they were seeing were especially bad. Lucky for the flu, and unluckily for humanity, a military base is just about the perfect place for a flu virus to frolic.
Erin Ryan: That’s a lot of people living in close quarters, getting yelled at, breathing heavily from physical exertion.
Abdul El-Sayed: You can imagine that virus being called a maggot by like, some really overzealous overcaffeinated drill sergeant.
Erin Ryan: Totally.
Abdul El-Sayed: Anyway, because we were in the middle of a pretty serious war. Groups of military personnel, some of whom were carrying the virus with them, were being sent off also in close quarters to far flung parts of the US and all over the world, where they would then often sit in crowded foxholes on crowded boats and train cars, etc. By that May, the 1918 flu had made it to France, where it burned its way from west to east.
Erin Ryan: So from the H1n1 flu virus’s perspective, World War One was like a bacchanalian party bus all around the world.
Abdul El-Sayed: So that virus got passed around every transport boat, like a joint at a drum circle. The virus kept mutating and getting stronger and meaner.
Erin Ryan: I’m going to ask an extremely non doctor question here, but how does a virus like know aren’t they’re like barely alive, right?
Abdul El-Sayed: Yeah, it’s a really good question, Erin. It’s a numbers game. Remember how I mentioned that RNA viruses are always making mistakes when they replicate? Eventually, a mistake inadvertently yields a stronger version of the virus. And the more times a virus replicates, the more chances it has to mutate into a much more transmissible pathogen.
Erin Ryan: Okay, so 1918 was basically the H1n1’s training montage. It was getting everything a germ could want. Lots of hosts, easy transmission, free tickets for travel around the world. But we’re not fighting a trench based World War right now. And as far as I know, wild birds aren’t sleeping in barracks. So can we breathe a sigh of relief that this one still has to find a more efficient way to get around?
Abdul El-Sayed: Well, I hate to break it to you, Erin. There is something in common with the way the 1918 virus got around and the way this H5n1 is getting around.
Erin Ryan: Is there some kind of bird war going on?
Abdul El-Sayed: So we mentioned earlier that this particular strain of bird flu has made its way to, well, dairy cows. Where do these factory farmed cows sleep, eat and live?
Erin Ryan: Well, it’s not in spacious 12,000 bedroom ranch style houses, that’s for sure.
Abdul El-Sayed: Oh, come on, in this economy. No way. You’re right. Livestock on commercial farms are crammed in a small a space as farmers can get away with. In many places, they’re not allowed much time outdoors. And sometimes farmhands are not as diligent at cleaning milking equipment as they should be.
Erin Ryan: Because commercial farmers are trying to maximize profits and also fuck them cows.
Abdul El-Sayed: So you’ve got lots of potential hosts crammed in a small space. And in the US, cows are often transported long distances. Hmm. Groups of potential hosts traveling long distances without tight infection controls to mitigate the spread of this particular pathogen.
Erin Ryan: How very 1918.
Abdul El-Sayed: That’s right. To a virus like H5n1 that has made the leap from bird to mammal, American factory farms might as well be trenches in World War One. Plus, people are more urbanized and globalized than we’ve ever been. Urbanicity increases density. You know, the number of people packed together in a subway every day, for example. Globalization means that a virus can hop a ride from China to NYC or Siberia to Rio.
Erin Ryan: From pale horse, pale rider to pale cow, pale milk. I guess.
Abdul El-Sayed: I know you’re joking, but there’s another reason that cows make such an ideal vector for this avian flu to potentially make its way to humans. It’s not killing them.
Erin Ryan: So these cows, they’re just getting the sniffles and working remotely.
Abdul El-Sayed: Basically, they’re living our 2020 reality right now. Viruses don’t benefit from killing their hosts too quickly. They want to infect as many hosts as possible. So these dairy cows that have H5n1 are feeling a little under the weather. Maybe not eating or drinking as much, but they’re not dying rapidly because of the disease.
Erin Ryan: Yeah. Come to think of it, I haven’t seen any dead cow B-roll on TV coverage of this virus.
Abdul El-Sayed: And that’s because this virus. Well, it turns out not to be very pathogenic in cows. Remember, it doesn’t make them all that sick. Now, that could change as the virus mutates. And it has mutated quite a bit since it first showed up.
Erin Ryan: And when was that? I mean, it was just a couple of years ago that some bird flu or another was killing all the chickens. And that’s why eggs suddenly cost like $8. And for some reason, most of the news coverage of that bird flu was about how much it was costing us at the grocery store, and not how we were living through the chicken plague.
[clip of unidentified news reporter number 4] Prices have risen for lots of foods, but the cost of eggs climbed the most in the last year, and consumers and businesses have scrambled to keep up.
[clip of unidentified person] One egg.
[clip of unidentified news reporter number 5] A disappointing result but a common occurrence for many farms across the state.
[clip of unidentified person] This is the price of a dozen jumbo eggs at Windmill Farms in Del Cerro today.
[clip of unidentified person] If that’s absolutely ridiculous, the price of eggs.
[clip of unidentified person] It is getting a little bit concerning.
Abdul El-Sayed: Yeah, that was the same flu, Erin.
Erin Ryan: What? The bird flu that gave brunch places across America an excuse to charge $16 for two sunnyside up eggs, toast and bacon. That was the same flu we’re living through right now?
Abdul El-Sayed: The very same. In fact, this strain of H5n1 was first observed in 1996, in waterfowl in southern China. It reemerged in the mid-aughts and then again in 2021. That’s when we started to see a lot more spread, particularly throughout North America. It’s been jumping into different mammalian species, including mink, bottlenose dolphins, sea lions, cats and now dairy cattle.
Erin Ryan: Dolphins, sea lions, is this like a Little Mermaid disaster happening right now?
Abdul El-Sayed: It’s the version of The Little Mermaid where a bunch of sick birds shit all over the top of the ocean.
Erin Ryan: Oh, okay. Yeah. I don’t think I want to watch that one.
Abdul El-Sayed: So the theory is that both species had contact with wild birds, possibly by eating their meat, possibly by having bird droppings infect their food or water supply. And it turns out that this bird flu was particularly pathogenic in sea lions. There were entire beaches and parts of the world covered with dead sea lions and their pups.
Erin Ryan: Not to mention the number of domesticated chickens that died.
Abdul El-Sayed: Well, lucky for brunch, the chicken population has rebounded. Remember, diseases like this come in waves, just like Covid does. And animals pick up immunity to a virus over time, just like we do. But during that wave, more than 90 million chickens died.
Erin Ryan: That’s more chickens than there are people in Turkey. [music break]
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Erin Ryan: Okay, this virus has already done some interspecies hopping, and it’s made its way from birds to mammals. What happens when an animal virus makes its way from mammals to people?
Abdul El-Sayed: A virus can cause what’s called a zoonotic illness when it jumps between animals and people. In fact, almost every pandemic happens when a virus does exactly that. A virus that humans haven’t been exposed to and therefore don’t have an immune response to, then jumps into us and it finds a way to spread between us. And that happened back when I was in med school in 2009. The world saw an outbreak of just such a zoonotic virus, the quote, “swine flu.” Here’s ABC’s coverage at the time:
[clip of unidentified ABC news reporter] This is believed to be ground zero in the swine flu outbreak. La Gloria, a remote Mexican farming village that time forgot and that the world would never know but for a five year old boy who was very, very sick with swine flu a month ago.
Erin Ryan: I think I was busy being an idiot in 2009. Definitely not in med school, and I wasn’t paying much attention to existential viral threats to humanity. I miss those days. So what exactly was that swine flu?
Abdul El-Sayed: Swine flu, as it sounds, was an influenza that was endemic, meaning common in swine. It hopped into people and then figured out how to transmit between people. In this case, it appears that there was likely a pig that had been co infected with human H1n1. In fact, the same influenza that caused the 1918 flu pandemic, and it swapped DNA with other viruses native to pigs, likely in central Mexico, which then made it illegible to our immune systems and caused a pandemic.
Erin Ryan: Hold the phone. Two viruses infecting the same host at the same time can combine to form a Frankenvirus that can evade immunity?
Abdul El-Sayed: Yeah, super cool trick, right?
Erin Ryan: Yeah. Cool trick. So people started getting infected with swine flu, and then what happened?
Abdul El-Sayed: Well, thankfully, it wasn’t as deadly as it could have been, killing 0.01% of people, though it still took between 151,000 lives and 575,000 lives.
Erin Ryan: Well, even on the low end, that’s still a lot of people.
Abdul El-Sayed: Remember transmissibility, pathogenicity and immune evasion. 2009 so-called swine flu wasn’t very transmissible, nor very pathogenic. Once the virus jumped into humans, it started to spread among us. Though misconceptions about the notion that one might contract the virus from pigs led to a significant culling of the animals.
Erin Ryan: And that’s how farmers handled that wave of H5n1 infections that impacted egg laying chicken flocks, right? Because birds were almost certainly going to die anyway once they were infected. And so you might as well just kill the whole flock once one bird gets sick.
Abdul El-Sayed: That’s right. And farmers in the U.S. would be reimbursed for their loss if they were proactive about culling sick flocks.
Erin Ryan: But obviously, this bovine iteration of H5n1 must be handled differently than another bird based outbreak would be.
Abdul El-Sayed: Yeah. That’s right. On one hand, the situation is a lot more precarious, as it’s a lot easier for a virus to jump from mammal to human than it is from bird to human.
Erin Ryan: Okay, explain this to me like I’m five.
Abdul El-Sayed: We’re mammals. Cows are mammals, so they’re like us. And the inside of their nose is a lot more similar to ours than it is to the inside of a bird’s nose. And the version that’s spreading in cows has learned how to spread in the kind of anatomy that we have, very different than the ones that birds have.
Erin Ryan: And to breed and raise cows also takes much more time and resources than breeding and raising chickens. So we’d probably be hard pressed to find farmers who would be as willing to immediately cull herds of sick cattle.
Abdul El-Sayed: Yeah, you can imagine, cows are huge animals, and there’s a lot of worry on the part of the dairy industry about what that approach would mean for their animals and the dairy industry as a whole.
Erin Ryan: Right. But there’s obviously something that can be done, like steps that can be taken to keep this tamped down. Right?
Abdul El-Sayed: Remember back to Covid when everybody needed to isolate and we all kind of built these small pods. That’s kind of what you need to do with the cows. The way to stop this is to very strictly isolate infected cattle herds so that once the virus spreads within them and runs out of cattle to infect, it would lose steam. But that has to be strictly enforced.
Erin Ryan: Cut to herds of cows staying home and bingeing Tiger King so driven mad by isolation that they think it’s a good show. I mean, not to sound callous, but there are more important factors at play here than the profitability of the dairy industry. Like, for example, is the simple act of drinking milk going to lead to some kind of viral mutation that will end humanity, because some factory farmer didn’t want to write off a farming loss in 2024?
Abdul El-Sayed: Yeah, you’re right to question agribusiness as some sort of experts in virology. But for now, there’s no need to freak out about milk. The FDA, the gold standard for food information, just recently tested 297 samples of milk from 38 states, including every single state where there’s been infected cattle. And they found no evidence of live virus in pasteurized milk.
Erin Ryan: No virus in steak?
Abdul El-Sayed: It’s kind of weird, but we’ve only seen this in dairy cattle, not beef cattle. So eat all the beef tartare you want.
Erin Ryan: If I had a dollar for every time I’ve heard the phrase eat all the beef tartare you want, I’d have $1. So you did say pasteurized milk. I’m assuming that raw milk is not a great call right now.
Abdul El-Sayed: Yeah, frankly, it’s not a great call most of the time. If you’re not personally familiar with the health of the cows it comes from, but especially right now when there’s literally a mutated strain of bird flu circulating among dairy cattle, consuming dairy products made from unpasteurized milk would be not the best idea, so you should avoid it.
Erin Ryan: Okay, so for the average consumer, avoiding raw milk is much easier than avoiding all dairy. Plus, don’t we know a lot more about influenza than we did about Covid 19 when it first hit?
Abdul El-Sayed: Yeah, that’s a really important point. We know a lot about the flu. It’s been around for over 100 years. We have effective vaccines that people have been taking for decades. We know how it behaves, who it tends to hurt the most and how to treat it. So this isn’t a novel pathogen scenario like we had during Covid 19.
Erin Ryan: I hate to sound like a PETA billboard, but maybe this is yet another sign from the universe that we should consume fewer animal products?
Abdul El-Sayed: Yo, it’s been telling us. Okay, but jokes aside, the number one cause of deforestation is cattle ranching, and that’s putting cows closer and closer to wild animals who are reservoirs for the kinds of viruses that could cause the next big pandemic.
Erin Ryan: So it sounds like most of the pieces are in place for some future wave of H5n1 to unleash something horrible on humanity. We’ve got a lot of potential hosts jammed into small spaces and occasionally being moved long distances a la the 1918 strain of H1n1. We’ve got a large population of cows passing the virus back and forth, giving it optimal chances to evolve into something that can make people sick. Like what happened during the swine flu outbreak. Uh. We have a couple of odd cow to human transmissions, but we should probably talk about another factor at play here. I’m starting to think Abdul, based off this conversation that we’ve been worried about the wrong things when it comes to this particular bird flu.
Abdul El-Sayed: What do you mean?
Erin Ryan: Well, when it hit chickens in 2022, we were worried about egg prices and not the fact that it could devastate entire animal populations. And this time around, we’re back to talking about the food supply and not other more likely ways that a cow to human version of H5n1, might take off.
Abdul El-Sayed: Yeah, I got to tell you, as a local public health director, there are a few things about this virus that do keep me up at night, and none of them are whether or not I can eat soft cheeses.
Erin Ryan: Yeah, like we discussed, conditions on factory farms would make it easy for this virus to get around.
Abdul El-Sayed: And it’s not just animals we concentrate in unhygienic spaces sadly, it’s also the people we ask to do the farming work. Too often we’re talking about marginalized migrant laborers who bunk in close quarters, don’t have access to health care, and have a lot of incentive not to interact with the government. That’s a recipe for disaster. But there’s also Covid fatigue.
Erin Ryan: Boy, is there ever. When we discussed swine flu, I kept thinking back to the media and information environment we lived in back then. Obviously, 2009 mass media had its limits. I mean, Tumblr was huge, but people in the US largely trusted mass media sources like there weren’t vast disinformation apparatuses operating on social media platforms and on fringe right wing YouTube channels. And not to mention the fact that it seems like the Covid pandemic and the government’s response to it kind of messed a lot of people up. Like the post 2020 world feels so much angrier, meaner, more distrusting. People are so isolated and algorithmically designed information silos that I’m not sure how actual good information could get to them if, God forbid, this virus mutates its way to humans.
Abdul El-Sayed: Yeah, I’m really worried about that. There’s so much unresolved trauma, society wide from the pandemic that the politicization of public health could render our tools moot. Here’s the thing, though. We dodged one big bullet with Covid. It didn’t really make kids all that sick. Flu, we know does. And that’s the thing I’m most worried about.
Erin Ryan: And of course, after the Covid pandemic stretched parents to their limit, the US government has helpfully responded by making zero helpful changes to the social safety net meant to support families. Still no paid leave. Republicans fought to let the expanded child tax credit expire, and nothing is being done to address the problem of teachers quitting in droves. Funding to make childcare more affordable has run out. I guess when problems present themselves and those responsible for solving them don’t solve them. Maybe we are doomed to be stuck in a time loop.
Abdul El-Sayed: Yeah, as a parent, I sadly endorse this message.
Erin Ryan: Well, Abdul, you were right.
Abdul El-Sayed: You’ll have to be more specific. I’m usually right about a lot of things. Erin, I don’t know if I told you this. I’m a doctor.
Erin Ryan: Ah. How could I forget? Okay, you were right that talking to you about the H5n1 avian flu did not help me freak out less. It simply helped me reorganize my anxiety.
Abdul El-Sayed: Look, I’m an epidemiologist, but my wife, she’s a psychiatrist and maybe she can help you with that.
Erin Ryan: Oh, that sounds great. Give her my number once we stop this recording. Uh. But there is one more thing I’d like to bring up to support my maybe we’re living in a time loop thesis.
Abdul El-Sayed: Do go on.
Erin Ryan: So in 1918, there was a total solar eclipse that traveled across the U.S., including Kansas, where Camp Funston is located.
Abdul El-Sayed: Camp Funston again being that military base where the H1n1 outbreak is now thought to have originated.
Erin Ryan: Okay, so just last month, we had another total solar eclipse, part of it passed over Texas.
Abdul El-Sayed: Where the first known cow to human transmission of the H5n1 flu occurred. You bring up some important points here, Doctor Ryan. Can’t let the moon off the hook too fast. But also, if you want some real science takes on scary diseases and more, do check out my podcast, America Dissected, where this is all we do.
Erin Ryan: That’s all the time we have for this week’s scary pandemic deja vu episode of How We Got Here. Play us out MIA. [clip of MIA song plays]
Max Fisher: How We Got Here is written and hosted by me, Max Fisher, and by Erin Ryan.
Erin Ryan: It’s produced by Austin Fisher. Emma Illick-Frank is our associate producer.
Max Fisher: Evan Sutton mixes and edits the show.
Erin Ryan: Jordan Cantor sound engineers the show. Audio support from Kyle Seglin, Charlotte Landes and Vasilis Fotopoulos.
Max Fisher: Production support from Adriene Hill, Leo Duran, Erica Morrison, Raven Yamamoto, and Natalie Bettendorf.
Erin Ryan: And a special thank you to What a Day’s talented hosts Tre’vell Anderson, Priyanka Aribindi, Josie Duffy Rice and Juanita Tolliver for welcoming us to the family. [music break]
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