Speaker 1: Hi, I'm Aaron Welsh and this is this Podcast Will
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Speaker 1: w k Y book Club series, where I get to
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Speaker 1: By now, we are all fairly familiar with the concept
Speaker 1: of the microbiome, the community of microbes that live in
Speaker 1: a particular environment, such as your gut, or your skin,
Speaker 1: or maybe even inside your belly button. But how many
Speaker 1: of you have heard of the aerobiome. We don't often
Speaker 1: think of the air as a medium teeming with microbial life,
Speaker 1: but as Carl Zimmer demonstrates in his latest book Airborne,
Speaker 1: The Hidden History of the life We breathe, that may
Speaker 1: be a critical oversight. In this book Club episode, award
Speaker 1: winning science writer Carl Zimmer joins me to discuss the
Speaker 1: long neglected science of aerial life and the public health
Speaker 1: implications of this research. Many of you may recall the
Speaker 1: debate that sprung up seemingly out of nowhere in the
Speaker 1: first couple of years of the COVID pandemic, when scientists
Speaker 1: couldn't seem to agree on whether the virus was transmitted
Speaker 1: via respiratory droplets or whether it was airborne. Why this
Speaker 1: distinction mattered and how the issue grew so contentious is
Speaker 1: just part of what Zimmer covers in Airborne. By placing
Speaker 1: this debate in the broader context of the history of
Speaker 1: aerial biology, he draws a line from the early days
Speaker 1: of germ theory to the pioneers of this emerging field,
Speaker 1: from the height of biowarfare research to a Washington State
Speaker 1: choir in the first weeks of the COVID pandemic. Linking
Speaker 1: together these disparate stories from the history of science, Zimmer
Speaker 1: presents a revelatory picture of a scientific field you didn't
Speaker 1: know existed. How might the COVID pandemic have been different
Speaker 1: if we acknowledged the airborne potential of this virus earlier?
Speaker 1: What lessons can we draw from this oversight to apply
Speaker 1: to future outbreaks? What even lives in the air, and
Speaker 1: why does it matter? We get into all of these
Speaker 1: questions and so many more. According to a quick Google search,
Speaker 1: we breathe about twenty two thousand breaths a day, breaths
Speaker 1: that we don't often think about, but after this episode,
Speaker 1: you'll have a newfound respect for those breaths and the
Speaker 1: invisible airborne life all around us.
Speaker 2: I am very.
Speaker 1: Excited to be bringing this episode to you, so let's
Speaker 1: just take a quick break and get started. Carl, thank
Speaker 1: you so much for joining me today.
Speaker 2: Thanks for having me.
Speaker 1: I have long been such a fan of your work,
Speaker 1: and I really especially appreciated your latest book, Airborne, which
Speaker 1: tells us really fascinating story of discovery, dismissal, and then
Speaker 1: ultimately kind of redemption in the end. To start us off,
Speaker 1: can you give us this big picture view of what
Speaker 1: the story that you explore in your book and what
Speaker 1: inspired you to write about it.
Speaker 2: The story is about the air and how humanity has
Speaker 2: slowly come to appreciate the fact that it's alive. In
Speaker 2: other words, we really are walking around on the floor
Speaker 2: of a giant, living ocean that is filled with trillions
Speaker 2: upon trillions of organisms, thousands of different species, a few
Speaker 2: of which we can see, you know, we can, you know,
Speaker 2: see a goose flying overhead, but for the most part,
Speaker 2: it's totally invisible to us. And I guess I say
Speaker 2: this the seed of this book came about during the
Speaker 2: COVID pandemic. I was working at the New York Times,
Speaker 2: and I, along with my colleagues, we were just trying
Speaker 2: to write as fast as we could about this totally
Speaker 2: new disease. And you know, it was challenging because scientists
Speaker 2: themselves are trying to figure out what exactly this disease
Speaker 2: is like. And one of the biggest sumbling points, one
Speaker 2: of the areas with the most debate and uncertainty, was
Speaker 2: how it spreads. You had people telling you on TV
Speaker 2: to wipe down your groceries. I know I did, and
Speaker 2: just you know, keep your distance from people, and you know,
Speaker 2: you'll be fine. Then there were other there were scientists,
Speaker 2: a small number of scientists at first, who were saying,
Speaker 2: we think this might be airborne. World Heart Organization explicitly
Speaker 2: saying COVID is not airborne, and you know, it took
Speaker 2: a couple of years, and then world health organizations that yeah,
Speaker 2: it's airborne. And I just thought, why was that so hardy?
Speaker 2: And the scientists themselves said to me, like, well, you
Speaker 2: need to understand the history. One scientist said, you know,
Speaker 2: history set us up. And so that led me down
Speaker 2: this path to discover this whole history of this science
Speaker 2: of the life in the air, which is called aerobiology.
Speaker 1: Yes, and as you discussed, you know this, we're living
Speaker 1: underneath this ocean of all of these different organisms. This
Speaker 1: the aerobiome. What can you tell me about the aerobiom
Speaker 1: Like who's up there? Who's floating around besides the geese
Speaker 1: that we.
Speaker 2: See, well, all sorts of things. The numbers are kind
Speaker 2: of crazy. I mean, actually you have to write them
Speaker 2: down and double check them because I'm like, did I
Speaker 2: get that right? Because they're just so I'll just give
Speaker 2: you one example. So insects. Okay, so you know you
Speaker 2: presumably seen you know, some dragonflies flying by, or maybe
Speaker 2: like a little swarm of mayflies or what have you.
Speaker 2: I mean, it's not unusual to see an insect in
Speaker 2: the air, but scientists have long suspected that that maybe
Speaker 2: large numbers of insects flying long distances high in the air,
Speaker 2: thousands of feet in the air. The problem is you
Speaker 2: can't see them, and so scientists have invented technology st
Speaker 2: barring radar and tuning it so that you can detect
Speaker 2: insects that are in large numbers that are way up
Speaker 2: in the air. Lo and behold, there are a lot
Speaker 2: of insects up there. And just to give you one example,
Speaker 2: and there's a study that came out last year and
Speaker 2: from China where just in a small region of China,
Speaker 2: they set up some radar systems to look up and
Speaker 2: over the course of a year they recorded nine point
Speaker 2: four trillion insects just in that place.
Speaker 1: I can't comprehend that.
Speaker 2: Yeah, yeah, right now, these numbers are incomprehensible. When you
Speaker 2: get to fungi, you walk around in a forest trail,
Speaker 2: you see some mushrooms. You think you know what fungi are,
Speaker 2: but you really don't, because they're everywhere. They're on everything,
Speaker 2: and they make a living by sending their spores into
Speaker 2: the air. I mean they have adapted beautiful like little
Speaker 2: cannons and other devices to get their spores up high
Speaker 2: enough so that the air can carry them away and
Speaker 2: then they can go all the way up to the stratosphere.
Speaker 2: Fungi loan they lift up about a trillion trillion spores
Speaker 2: every year.
Speaker 1: Again, I can't I don't know what that means even
Speaker 1: right right.
Speaker 2: What do you do with that? The you know they're
Speaker 2: back also bacteria, viruses, algae like and again they probably
Speaker 2: comprise thousands tens of thousands, maybe millions of species. You know,
Speaker 2: we've barely begun to sample this habitat, this living habitat
Speaker 2: in the air called the aerobiome.
Speaker 1: And I love how you describe it as an ecosystem
Speaker 1: of visitors. You know, this is a for most of
Speaker 1: these species. This is a transitory period. If you take
Speaker 1: one you know, cubic meter of air or something wherever
Speaker 1: it is, how often that changes just within a second,
Speaker 1: within a minute, within a day, it's completely different.
Speaker 2: Yeah, it really depends for the individual organism on how
Speaker 2: high they get up initially, you know, and what the
Speaker 2: air conditions are like when they get lofted into the air.
Speaker 2: The oceans, for example, every time a wave breaks, there
Speaker 2: are lots of tiny droplets that rise up, and some
Speaker 2: of them have bacteria, viruses, other marine organisms in them. Now,
Speaker 2: if there's enough of a breeze, they may get carried
Speaker 2: up and maybe they fall right back down after you know,
Speaker 2: a few seconds. But it is possible for them to
Speaker 2: go up and then keep going up, and then eventually
Speaker 2: they get so high that they're just riding along long
Speaker 2: distance waves and they can actually go thousands of miles,
Speaker 2: so they can be floating for days. You know eventually
Speaker 2: they will land. I mean, it's just a matter of time.
Speaker 2: But because there's so many things coming up all the time,
Speaker 2: it's always a very lively space. So like the clouds,
Speaker 2: for example, every cloud you look at is alive. It's
Speaker 2: it's got you know, trillions of bacteria something something on
Speaker 2: the order of that. And you know the bacteria, there
Speaker 2: are signs that they might be growing in the clouds,
Speaker 2: and that means that they are eating the clouds. So
Speaker 2: you know, it's a different way to look at the
Speaker 2: sky and think about what's up there.
Speaker 1: Let's take a short break, and when we get back,
Speaker 1: there's still so much to discuss. Welcome back everyone. I've
Speaker 1: been chatting with Carl Zimmer about his latest book Airborne,
Speaker 1: The Hidden History of the life We breathe. Let's get
Speaker 1: back into things. Which certain types of pathogens are more
Speaker 1: likely to be airborne? Do they share certain evolutionary history
Speaker 1: or drivers that might make them more likely to be airborne.
Speaker 2: That's a really good question, and I honestly, I don't
Speaker 2: think anybody has a good answer for you. Yet. Part
Speaker 2: of the challenge is it's hard to really carefully study
Speaker 2: airborne disease if you're talking particularly about pathogens. Now, certainly
Speaker 2: there are some very familiar pathogens that are clearly we
Speaker 2: know are airborne, but that's by no means an exhaustive list.
Speaker 2: There probably are lots of other things that we are
Speaker 2: not appreciating fully yet. But just to give a couple examples,
Speaker 2: the biggest infectious disease killer by far is tuberculosis. It's
Speaker 2: caused by bacteria, and those bacteria are totally airborne. In
Speaker 2: other words, they really can't infect people in any other
Speaker 2: way other than people releasing little droplets that float out,
Speaker 2: not just you know, maybe when they cough or sneeze,
Speaker 2: but even when they're just breathing, they are going to
Speaker 2: release droplets, some of which have tuberculosis bacteria in them.
Speaker 2: These are so good at being airborne that they actually
Speaker 2: manipulate us. They actually have adaptations to sort of essentially
Speaker 2: tickle our airway to get us to cough more, because
Speaker 2: that gets them out and gets them into the air,
Speaker 2: propels them and then they can float off and infect
Speaker 2: someone else, and they make the droplets make their way
Speaker 2: into the very finest tips of our airway endings. In
Speaker 2: the lungs, the lvoli and that's where the bacteria can grow.
Speaker 2: So tuberculosis kills over a million people a year. But
Speaker 2: you know, it's also a huge threat to in terms
Speaker 2: of pathogens. It's also a huge threat to our crops.
Speaker 2: So there are lots of disease is, particularly fungi that
Speaker 2: spread through the air in part or entirely. I write
Speaker 2: a lot about a kind of fungus called rust, which
Speaker 2: can just you know, it can endanger the food supply
Speaker 2: of whole countries if it really breaks out seriously. So
Speaker 2: I'm just giving you two examples, but there's a long list.
Speaker 2: And you know, is there something about airborne pathogens that
Speaker 2: you know they all have in common? I would say
Speaker 2: they're rugged in the sense that they can survive being
Speaker 2: floating around in the air. It's not easy to be
Speaker 2: a pathogen floating around out in the air. It's hard.
Speaker 2: And there's some viruses that don't last very long when
Speaker 2: they're exposed air. Other viruses can last a really long time,
Speaker 2: and it might be that they sort of they have
Speaker 2: adaptations that let them kind of use the chemicals inside
Speaker 2: of those droplets that come out of our lungs to
Speaker 2: sort of shield themselves from the elements.
Speaker 1: This respiratory droplet versus airborne debate, you know, as you say,
Speaker 1: really took center stage during COVID as we all remember,
Speaker 1: and kind of, like you it seemed baffling, like why
Speaker 1: is this so controversial? Why is this something that we're
Speaker 1: so resistant to the idea of this being airborne, especially
Speaker 1: when it seemed like, you know, this research had been
Speaker 1: going on for quite some time. And before we get
Speaker 1: into how that controversy started in the germ theory myasthma debate,
Speaker 1: what role did people think the air played in diseases
Speaker 1: before germ theory.
Speaker 2: So if you go all the way back to say Hippocrates,
Speaker 2: in the sort of the world of Western thought in particular,
Speaker 2: there was this idea that obviously, you know, air is
Speaker 2: essential to us. The Greeks considered it, you know, one
Speaker 2: of the main elements we obviously we need to breathe.
Speaker 2: But people couldn't really say why. And yet there was
Speaker 2: sort of a sinister dark side to the atmosphere. And
Speaker 2: you know, like I mean, we've all, I suppose we've
Speaker 2: all had that experience walking around. It's you know, today
Speaker 2: here in Connecticut, it's a beautiful sunny day. The air
Speaker 2: feels very lovely, but you know there are also days
Speaker 2: where you like, it smells really wrong, or there's a
Speaker 2: there's a weird light in the sky because there are
Speaker 2: wildfires someplace, and you know, like the the air is unpredictable.
Speaker 2: And so Greeks had this idea that gods could visit
Speaker 2: curses on them and they would call these miasthmas. And
Speaker 2: Hippocrates said sort of took that name and applied it
Speaker 2: to what do you call it, like corruptions of the air,
Speaker 2: so that if you breathed in that air, you would
Speaker 2: become sick. And there were different miasthmas for different diseases,
Speaker 2: and even different species could get different diseases because they
Speaker 2: had their own miasthmas, but they were all transformations of
Speaker 2: the air itself. It had a certain explanatory power. I mean,
Speaker 2: how was it that, you know, a bunch of people
Speaker 2: in this same town all would get the same disease
Speaker 2: around the same time. You can imagine, well, you know,
Speaker 2: a breeze just came through and people all inhaled it
Speaker 2: and then they all keeled over. But that explained plague,
Speaker 2: and you know influenza, and you know malaria literally like
Speaker 2: bad air, like that's what the disease name means. And
Speaker 2: so it held on for a long long time until
Speaker 2: people who had been discovering and studying microbes said no, wait,
Speaker 2: we think these are responsible for these diseases. And it
Speaker 2: was a very you know, it was a very long
Speaker 2: slog I mean to us in hindsight, it seems obvious,
Speaker 2: but you know, this was a battle that started around
Speaker 2: seventeen hundred and lasted up until about nineteen hundred, so
Speaker 2: about two hundred years of a long drawn out fight.
Speaker 1: It seems like a blink of an eye, like Louis
Speaker 1: Pasture came in and solved everything, But it's not. That's
Speaker 1: not what actually happened. But I think it's it's so
Speaker 1: interesting to think about miasma and airborne transmission because they
Speaker 1: seem like almost the same thing, right, Like, how was
Speaker 1: that distinction made between microbes in the air causing disease
Speaker 1: and miasma causing disease?
Speaker 2: There were a lot of confusing, seemingly contradictory pieces of
Speaker 2: evidence flying around. So Louis Pasteur, who you mentioned it
Speaker 2: was an architect of the germ theory disease. He actually
Speaker 2: was the first person to really clearly demonstrate that there
Speaker 2: were germs floating in the air. And people said at
Speaker 2: the time when he was trying to persuade them of this,
Speaker 2: that this was crazy. One journalists said, this is you
Speaker 2: want to lead us into a world that's too fantastic
Speaker 2: to believe. I love that line. But he would go
Speaker 2: outside with flasks and he would catch bacteria. They would
Speaker 2: fall down the long neck of the flask and fall
Speaker 2: into sterile broth and start multiplying. And he did it
Speaker 2: in Paris streets, he did it in farmland around France,
Speaker 2: and the even climbed a glacier, which was my favorite
Speaker 2: episode of this. And he actually initially said that he
Speaker 2: thought that lots of diseases were caused by these floating germs,
Speaker 2: by airborne germs, but it didn't really go that way,
Speaker 2: and what happened instead was that as as scientists definitely
Speaker 2: showed that the diseases were caused by germs. So, for example,
Speaker 2: cholera not caused by miasma as the authority is claimed. Instead,
Speaker 2: it was caused by Fibrio cholerae, like one particular bacteria,
Speaker 2: and that particular bacteria spread in water, so you have
Speaker 2: a water borne disease and then you have other bacteria
Speaker 2: that get into food and contaminate food, so you have
Speaker 2: food borne diseases. You have you know, bacteria that spread
Speaker 2: through sex, sexually transmitted diseases, and on and on and on.
Speaker 2: So it was like the germ theory disease was taking
Speaker 2: one disease after another out of the air. Yeah, and
Speaker 2: by the early nineteen hundreds you had very prominent public
Speaker 2: health figures saying we don't need to worry about the
Speaker 2: air anymore, like this should be a relief. The air
Speaker 2: has been this specter of infection since Hippocrates. They literally
Speaker 2: said this, and now you don't need to worry that.
Speaker 2: I think that really did keep people from really thinking
Speaker 2: very much about life in the air. And they also
Speaker 2: didn't have very good technology for really measuring and capturing
Speaker 2: life in the air. So that combination really did lead
Speaker 2: to a real, very strong consensus starting in the early
Speaker 2: nineteen hundreds that has endured for over a century.
Speaker 1: Let's take a quick break here, we'll be back before
Speaker 1: you know it. Welcome back. I'm here chatting with Carl
Speaker 1: Zimmer about his book Airborne, The Hidden History of the
Speaker 1: Life We Breathe. Let's get into some more questions. There
Speaker 1: were still some people that did remain intrigued by the
Speaker 1: concept of, you know, living things that the aerobiome. And
Speaker 1: I want to ask you about one of these, which
Speaker 1: is Fred Meyer. How did he end up turning what
Speaker 1: was first a hobby into this branch, this whole branch
Speaker 1: of science.
Speaker 2: Yes, Fred Meyer is a really remarkable figure, and it's
Speaker 2: kind of typical for early aerobiology figures completely forgotten, so
Speaker 2: you know, I had to dig into archives to really
Speaker 2: figure out what I could about his life. So I
Speaker 2: had mentioned before about, you know how there are these
Speaker 2: pathogens of plants, particularly of crops. So fred Meyer was
Speaker 2: a plant pathologist. He worked at the US Department of
Speaker 2: Agriculture ever since he was like twenty years old, was
Speaker 2: just his lifelong employer, and he was part of this
Speaker 2: tradition of studying diseases that affected crop like watermelon and
Speaker 2: wheat and so on. And they were very comfortable with
Speaker 2: the idea of airborne disease because there are these spectacular
Speaker 2: crop failures, like you know, the the Great Irish Famine
Speaker 2: that was caused by potato blight that in part was
Speaker 2: airborne that organism. So by the early nineteen hundreds, plant pathologists.
Speaker 2: They knew that things moved through the air, they just
Speaker 2: didn't know how far they could go or high they
Speaker 2: could go. And so eventually fred Meyer says, like, I
Speaker 2: am going to try to figure out how high and
Speaker 2: far I can go to catch them. And this was
Speaker 2: something that his bosses did not want him to do,
Speaker 2: so he just did it on the side on his
Speaker 2: off hours, and it's kind of spectacular. He would he
Speaker 2: would jump into planes, these open cockpit cockpit biplanes, and
Speaker 2: you know, he'd have these petra dishes stuck on to
Speaker 2: handle wooden handles, and he would just basically be waving
Speaker 2: his arms around out of a flying plane in the clouds,
Speaker 2: and the pilots would just be totally baffled by him.
Speaker 2: But he'd bring these prejudicies back to his lab and
Speaker 2: he would grow stuff. He was catching things. So then
Speaker 2: he started looking for opportunities to send more sophisticated devices
Speaker 2: higher and farther. So, for example, Charles and n. Lindberg,
Speaker 2: they flew in ninety thirty four across the North Atlantic
Speaker 2: over Greenland, and he talked them into trying to catch
Speaker 2: life as well, and they did. And then there were
Speaker 2: these explorers who got into sort of metal spheres that
Speaker 2: were attached to giant balloons, and they went up to
Speaker 2: the stratosphere, and so they took along with them probes
Speaker 2: that Meyer had to see if life could survive up
Speaker 2: in the stratosphere. And then on a second voyage, they
Speaker 2: actually were able to catch stuff up there in the stratosphere.
Speaker 2: Real kind of unbelievable to me is that by nineteen
Speaker 2: thirty seven Meyer had done assembled so much dazzling work
Speaker 2: that he was able to talk the government into creating
Speaker 2: a whole new service in the government, a kind of
Speaker 2: centralized lab for life in the air, and he was
Speaker 2: going to head it. He coined the word for the
Speaker 2: science that they were going to do, aerobiology. He came
Speaker 2: up with that word in nineteen thirty seven with this plan,
Speaker 2: and everything was looking great, and then he went on
Speaker 2: his you know, sort of made voyage across the Pacific
Speaker 2: in search of search of life and was never heard
Speaker 2: from again. So I feel sometimes writing about these people,
Speaker 2: there's there's a certain curse that hangs over aerobiology.
Speaker 1: I mean, I was shocked when that was like the
Speaker 1: twist in the story, But then also it did feel
Speaker 1: like fitting in a way like, of course this like
Speaker 1: there's more things, Like you said, Befell, these people that
Speaker 1: you know, you can't quite get their ideas and their
Speaker 1: evidence to take hold in the public eye, I think,
Speaker 1: in the public facing side of science. But as you
Speaker 1: talk about the military side of things, this really did
Speaker 1: gain hold. There was more interest in aerobiology and the
Speaker 1: potential of air as a way to transmit disease and
Speaker 1: how to protect ourselves from that. And I think it's
Speaker 1: interesting to think about these two sort of lenses through
Speaker 1: which people viewed aerobiology. You have Fred Meyer on the
Speaker 1: one hand, who's just interested in the rich tapestry of
Speaker 1: life in the air, and then you have more of
Speaker 1: the US government interest at the time, in part shaped
Speaker 1: by global politics, where it's like what about bioweapons, what
Speaker 1: about biodefense, And how did that branch kind of grow
Speaker 1: more or gain more interest than Meyer's side.
Speaker 2: Yeah, when World War two begins and then the United
Speaker 2: States is starting to prepare to enter, there was a
Speaker 2: serious concern that, you know, that Nazi Germany might be
Speaker 2: developing biological weapons that it might use in battle. I mean,
Speaker 2: it never have never been done before, but there was
Speaker 2: this great fear for decades. They were in a fear
Speaker 2: that someone might somehow deploy these these deadly germs against
Speaker 2: soldiers or even civilians. So the US government actually started
Speaker 2: to reach out to these aerobiologists. They would say, well,
Speaker 2: what do you think, what do you think are the
Speaker 2: what do you think are the risks that we face?
Speaker 2: And so there was one aerobiologist named Ellen Stackman who
Speaker 2: wrote a very long memo based a lot on the
Speaker 2: work that he and Fred Meyer and others had been doing, saying, yes,
Speaker 2: we could be attacked, and here's what could happen. So
Speaker 2: I mentioned stem rust. So he said, you could imagine
Speaker 2: someone dropping a stem rust bomb over our farms and
Speaker 2: wiping out our food supply, and you know, they someone
Speaker 2: like Stackman, who had, you know, been involved in World
Speaker 2: War One, could see like what happens when an army
Speaker 2: loses a food supply. Because Germany actually had its own
Speaker 2: potato light, you know, this airborne disease that was devastating
Speaker 2: to its food supply and that may have really tipped
Speaker 2: the balance of the war. So he said, we need
Speaker 2: to be aware of that. We need to have like
Speaker 2: plant pathologists looking out for attack and so on. But
Speaker 2: then it's quite amazing, like in writing, is like, we
Speaker 2: have to explore developing our own weapons. It would be
Speaker 2: remiss of us not to. It would be irresponsible for
Speaker 2: us not to start building our own arsenal. You know.
Speaker 2: It's kind of like the nuclear sort of logic, like, well,
Speaker 2: if they're going to be building him, well we should
Speaker 2: too as defense. And he had this He said, here's
Speaker 2: how you could like go after Japan. You know they
Speaker 2: have these rubber plantations for their tires for their vehicles. Well,
Speaker 2: here's a MicroB you could drop on their rubber plantations
Speaker 2: and wipe those out. He really thought a lot about this.
Speaker 2: And there were other aerobiologists, William and Mildred Wells, a
Speaker 2: husband and wife team who in the nineteen thirties had
Speaker 2: been showing how people can spread diseases to each other
Speaker 2: through the air. And William Wells in particular had developed
Speaker 2: all sorts of really elegant devices to demonstrate how germs
Speaker 2: can float in the air and also then to sort
Speaker 2: of measure how much you would need an animal to
Speaker 2: inhale to die. The military, you know, at Camp Dietrich,
Speaker 2: they started building very similar devices they took secretly without
Speaker 2: his awareness, They secretly started building these devices so to
Speaker 2: figure out, well, how instead of saying, like, well, how
Speaker 2: do we understand these airborne diseases to protect people? How
Speaker 2: do we build better weapons? Like what's the minimum dose
Speaker 2: we need of anthrax in the air to kill these mice?
Speaker 2: And they did all this resent in a giant building
Speaker 2: literally called the Aerobiology Building, and you know, the United States,
Speaker 2: the Soviet Union and other countries you know, would go
Speaker 2: on for decades to build huge stocks of biological weapons,
Speaker 2: all firmly based on this new science of air biology.
Speaker 1: I mean, that is such an interesting aspect of this story,
Speaker 1: where you have this acceptance of this idea of how
Speaker 1: much the air can contribute to the spread of disease
Speaker 1: and the potential there. So we have that happening in
Speaker 1: the military side of things, what was happening in the
Speaker 1: more public facing side of science and aerobiology with the Wellses.
Speaker 2: The Wells has come into the world of airbiology kind
Speaker 2: of in a very peculiar, sort of sideways manner. You know.
Speaker 2: William Wells, he gets a bachelor's degree at MIT and
Speaker 2: Sanitation and he goes off to study typhoid and water
Speaker 2: and he gets into studying how it is that oysters
Speaker 2: actually can be really dangerous to eat because they filter
Speaker 2: all the bacteria that caused typhoid, and you eat them
Speaker 2: raw and you die. And so he's trying to figure
Speaker 2: out how do I purify you oysters and so on,
Speaker 2: and then he gets pulled into World War One. His
Speaker 2: job is to clean the water for the soldiers, and
Speaker 2: so he is protecting, you know, American soldiers by providing
Speaker 2: clean water. But meanwhile they're dying of influenza, not a
Speaker 2: waterborne disease, and it's not really clear how it's spreading,
Speaker 2: but I think that the seeds were planted there that
Speaker 2: they thought maybe this is airborne, despite that prevailing view
Speaker 2: that diseases are not airborne. So he comes back from
Speaker 2: the war. He's married Mildred Wells. She had gotten a
Speaker 2: medical degree, but she didn't practice medicine. She was raising
Speaker 2: their son who probably had some sort of psychiatric disorders.
Speaker 2: Just judging from medical files, I was able to come
Speaker 2: across later. They have a good run. In the twenties,
Speaker 2: he continues studying oysters. He gets famous for being the
Speaker 2: oyster Godfather because he's figuring out how to breed oysters.
Speaker 2: And then the Great Depression comes and he's out of
Speaker 2: a job. Mildred somehow gets a job studying the epidemiology
Speaker 2: of polio, and she actually contributes to a book about it,
Speaker 2: and she develops this idea that maybe polio is being
Speaker 2: spread through the air. She doesn't really develop it a
Speaker 2: lot in her writings, but it definitely influenced William Wells.
Speaker 2: He gets a job at Harvard teaching. He's terrible at it,
Speaker 2: like just I mean, I'm not making it up, Like
Speaker 2: the dean of the school, bubble Galth says, this is
Speaker 2: something that Wells does very badly, Like it's in writing,
Speaker 2: and he in particular had a very difficult time with
Speaker 2: communication and just he would get into arguments with people
Speaker 2: or long long monologues. Mildred was really fierce herself. They
Speaker 2: didn't make friends, and put it this way, They're brilliant,
Speaker 2: but they alienated everybody. But at Harvard they start to
Speaker 2: do some experiments that actually established some of the basic
Speaker 2: ideas about airborne infection. In other words, that you know,
Speaker 2: when you breathe, you are releasing droplets and some of
Speaker 2: them have can have viruses or bacteria in them. They
Speaker 2: can float around for hours, maybe days in the right conditions,
Speaker 2: primarily in indoor spaces, and they even show that you
Speaker 2: can use ultraviolet light to kill them in the air.
Speaker 2: First they do this with, you know, with experiments on animals.
Speaker 2: But then when they moved to Philadelphia, they put ultraviolet
Speaker 2: lamps in a school and in nineteen forty there's an
Speaker 2: outbreak of a disease we's been hearing a lot about recently, measles.
Speaker 2: At the time, there was no vaccine, so people were
Speaker 2: just very resigned to this terrible disease sweeping through The
Speaker 2: Philadelphia school was substantially protected from this measle's outbreak by
Speaker 2: these ultra violet lamps. And you know, this was not
Speaker 2: stuff they did in secret. This was all heavily reported.
Speaker 2: People were very excited. They were like, wow, we'd maybe
Speaker 2: we don't have to worry about a new nineteen eighteen
Speaker 2: flu pandemic again, because we know that influences airborne and
Speaker 2: we have a way to protect ourselves from it. And
Speaker 2: yet nobody knows who the Wells is are these days.
Speaker 2: They just they crashed into obscurity later on, so you know,
Speaker 2: they might not have died in a plane crash like
Speaker 2: fred Meyer, but they had their own crash Nevertheless.
Speaker 1: That's another kind of mysterious disappearance of its own, Like
Speaker 1: why this work that could have such profound implications for
Speaker 1: public health just kind of went away, And I'm curious
Speaker 1: to hear your thoughts on why that might be. You know,
Speaker 1: was part of it any sort of taint that, like
Speaker 1: the military's interest in bioweapons, Like was that part of it?
Speaker 1: You mentioned, like antibiotics and vaccines and sort of the
Speaker 1: decline is like we're winning the war against infectious disease.
Speaker 1: What were some of the factors at play there?
Speaker 2: Yeah, I think there are many of these factors that
Speaker 2: you mentioned that we're all play. I think that first
Speaker 2: of all, epidemiology and trying to establish how diseases get
Speaker 2: from one person another. It's just difficult science. You need
Speaker 2: just the right opportunity and just the right conditions. You
Speaker 2: need to design your experiments just right to get really clear,
Speaker 2: compelling evidence. And so you know, if you're talking about water,
Speaker 2: like let's say that sewage is flowing into a river
Speaker 2: and a city is getting its drinking water supply just downstream,
Speaker 2: and there are a bunch of typhoid cases like this
Speaker 2: literally happened in Lowell, Massachusetts in the eighteen nineties. You
Speaker 2: can you know, you can say like, hey, let's stop
Speaker 2: getting our drinking water from there, shall we, and then
Speaker 2: lo and behold the typhoid goes away, you know, like
Speaker 2: so that there's a certain sort of control to that,
Speaker 2: whereas the air is like it's very hard to control.
Speaker 2: It's elusive, and while there is a lot of life
Speaker 2: in the air, like it's it's dilute, you know. So
Speaker 2: you might be breathing, you know, two thousand times a day,
Speaker 2: hundreds of thousands of times a month, but you know,
Speaker 2: it could just take one of those breaths for you
Speaker 2: to take in COVID or what have you, and boom,
Speaker 2: You've got an infection. So I'll just say it is
Speaker 2: hard to study. But you know, on top of that,
Speaker 2: I think there was this consensus that had really built
Speaker 2: in and people were very reluctant to shift away from it.
Speaker 2: So they just they would say, like, you need to
Speaker 2: really really persuade me that diseases can be airborne. So
Speaker 2: they really refused to look at good evidence. And yeah,
Speaker 2: and I think with the with the biological warfare research,
Speaker 2: it's arguable that a lot of the best evidence that
Speaker 2: diseases are in fact, airborne was being done in secrecy, right.
Speaker 2: It was being done you know, as classified research, and
Speaker 2: some of that is still classified today. So instead of
Speaker 2: being an open science, a science that was really like
Speaker 2: focused on human health and you know, and understanding ecosystems,
Speaker 2: a huge amount of effort in the air biology world
Speaker 2: went into building weapons. And so maybe people thought like, well,
Speaker 2: I suppose you could build a weapon that could really
Speaker 2: create an airborne disease, but that you need human intervention
Speaker 2: as opposed to just nature. So there were a lot
Speaker 2: of different a lot of different reasons. But what's remarkable
Speaker 2: is that even at the start of the COVID pandemic,
Speaker 2: a lot of these assumptions and a lot of these
Speaker 2: misunderstandings and so on that you can trace back a
Speaker 2: century were still present in public health guidelines. Yeah, and
Speaker 2: how and how public health organizations dealt with the COVID pandemic,
Speaker 2: they were still in place, right.
Speaker 1: And the message was respiratory droplet transmission.
Speaker 2: Well, and that just to clarify what they were talking
Speaker 2: about is like if someone is just a cough in
Speaker 2: your face and like a big old drop of like
Speaker 2: boom and just hits you in the face, that's what
Speaker 2: they're talking about. Whereas what someone like William Wells was
Speaker 2: talking about was saying, these tiny droplets that leave your
Speaker 2: nose in your mouth just as you breathe or talk
Speaker 2: or sing, and they can float. So those big droplets
Speaker 2: they drop to the ground because they're so heavy, the
Speaker 2: thinking was, But in fact, there's all these tiny droplets
Speaker 2: which can themselves have covid viruses or influenza viruses or
Speaker 2: you know, tuberculosis bacteria in them, and you know, they
Speaker 2: can fill a room if it's not well ventilated. They
Speaker 2: can fill a room like smoke. Think of those as viruses.
Speaker 1: And this is something that seemed to emerge during the
Speaker 1: first Stars epidemic in two thousand and two two thousand
Speaker 1: and three, with this idea that there was evidence for
Speaker 1: potential airborne transmission of this virus. Why didn't we remember
Speaker 1: those lessons? Is it just more of the same thing,
Speaker 1: just the stickiness of this idea that airborne transmission is
Speaker 1: a minor plays a minor role in the spread of
Speaker 1: most respiratory pathogens, Like, why why didn't we remember that?
Speaker 2: Yeah, it would have been great if we had so.
Speaker 2: In the SARS epidemic, what's really remarkable is that, you know,
Speaker 2: as this coronavirus, another coronavirus was emerging as a human disease.
Speaker 2: There were a few scientists who were getting dissatisfied with
Speaker 2: the standard view held that these must be spread by
Speaker 2: kind of you know, contact or very short range droplets.
Speaker 2: They're like, no, this is like spreading. It seems like
Speaker 2: it's spreading through like buildings. And they had to rediscover
Speaker 2: William and Mildred Wells. Like these people were like, h
Speaker 2: I keep seeing these references to William and Mildred Wells,
Speaker 2: Like who are these people? Like nobody knew who they were.
Speaker 2: And I talked to this one University of Hong Kong researcher,
Speaker 2: a named Hugo Lee, who is just a you know
Speaker 2: now is like a world expert on airborne and at
Speaker 2: the time he was trying to help understand SARS and
Speaker 2: he was like, h it looks like Wells has written
Speaker 2: a book. Wells wrote a book in nineteen fifty five.
Speaker 2: Nobody in Hong Kong had it, and the only place
Speaker 2: he could find it was in one university library in
Speaker 2: the United States, and he asked them to photocopy it.
Speaker 2: This is like the early two thousands. They so they
Speaker 2: photocopied the whole book for him and they mailed it
Speaker 2: to him. And then so he gets this big stack
Speaker 2: of photocopied pages and he starts reading it and he says, ah, okay,
Speaker 2: now this is making sense. These are droplets, okay. And
Speaker 2: it's crazy to think that he had to go to
Speaker 2: these measures to discover what had been widely reported and
Speaker 2: widely known in the nineteen thirties. You know that he
Speaker 2: had to dig this back up, and thank goodness he did,
Speaker 2: because then he did a lot of research on SARS
Speaker 2: and really demonstrated how with the way he was spreading
Speaker 2: through buildings and hospital wards and so on, it really
Speaker 2: did look like it was behaving like what William and
Speaker 2: Mildred Bells was talking about and airborne disease. The problem is,
Speaker 2: among other problems, is that SARS, it's sort of a
Speaker 2: good news band news thing. SARS was able to be
Speaker 2: controlled and then eradicated because all you needed to do
Speaker 2: is as soon as people showed symptoms, that's when they
Speaker 2: started becoming infectious. So you just be real careful about
Speaker 2: isolating people, you know, supporting them. Some of them died,
Speaker 2: you know, about eight hundred people died of SARS worldwide,
Speaker 2: but they rained it in and there is no stars anymore.
Speaker 2: So it wasn't something that you could be sort of
Speaker 2: steadying year in year out. It was just this one
Speaker 2: terrible moment in history. And you know, there were these clues,
Speaker 2: you know, these studies that said like, hey, maybe this
Speaker 2: is airborne, but I yeah, I'd say that it didn't
Speaker 2: really penetrate. You know, all the pandemic preparedness that came
Speaker 2: afterwards was all based on this idea that it would
Speaker 2: not be truly airborne.
Speaker 1: That shift did eventually happen during the COVID pandemic what
Speaker 1: came to a head to then finally change the tides
Speaker 1: to people realizing that airborne transmission is a real not
Speaker 1: just a real possibility, but like at the forefront of
Speaker 1: what is maybe spreading a lot of these cases.
Speaker 2: So there were people like Hugo Lee early in the
Speaker 2: pandemic in early twenty twenty who would say, you know,
Speaker 2: this seems to be spreading like an airborne disease, and
Speaker 2: they were just being emphatically ignored by public health officials
Speaker 2: or you know, people would just start brushing them off
Speaker 2: or saying no, no, there's the evidence says otherwise. And
Speaker 2: so this group of people, at first just you know,
Speaker 2: just a couple dozen experts, they got together and they
Speaker 2: tried to change the world health organizations the view on this,
Speaker 2: who didn't budge. So then they went public. They started
Speaker 2: trying to like gin up support. But it really took
Speaker 2: like a whole string of outbreaks and studies on those
Speaker 2: outbreak to really demonstrate it. I focus on one in
Speaker 2: particular that struck a choir in Washington State where on
Speaker 2: March tenth, twenty twenty, about sixty people gathered together one
Speaker 2: night to sing, and they were being careful, they were
Speaker 2: doing everything they were supposed to be doing, and no
Speaker 2: one seemed to be sick, no one was coughing, but
Speaker 2: there was an infected person who was breathing, and then
Speaker 2: you know, over fifty people came down with COVID in
Speaker 2: the next few days. It took time, unfortunately, to sort
Speaker 2: of to become aware of these outbreaks and then for
Speaker 2: these airborne advocates to say, like, hey, we're going to
Speaker 2: investigate these as sort of cases of airborne spread, see
Speaker 2: if we can test this hypothesis. And then eventually enough
Speaker 2: evidence emerged that satisfied a lot of people, and then
Speaker 2: the consensus shifted. I mean, I wouldn't you know, I'm
Speaker 2: there are people who will still say like, no, I'm
Speaker 2: not convinced, but you know, I would say like that
Speaker 2: most certainly most scientific societies that are relevant to this
Speaker 2: and so on, have all agreed that it's airborne. But yeah,
Speaker 2: it took a long time.
Speaker 1: It did, and it does I think beg the question
Speaker 1: of what could have been different if we had recognized
Speaker 1: this before COVID. I mean not just before stars, but
Speaker 1: just at least before COVID.
Speaker 2: If we had recognized it, there would be the at
Speaker 2: least the opportunity to deal with the disease as an
Speaker 2: airborne disease. You know, that takes a lot. I think
Speaker 2: another reason for the slow take up of, you know,
Speaker 2: recognizing this disease as airborne is that it's simpler to
Speaker 2: deal with a disease that is just caused by short
Speaker 2: range droplets or by contact. It is just it's a
Speaker 2: simpler process. If it's all around you, as like a smoke,
Speaker 2: then you've got to do different things. For one thing,
Speaker 2: we might have made sure, really sure that we had
Speaker 2: a real stockpile of protective equipment, which we didn't, so
Speaker 2: you know, people were just desperately reusing N ninety five masks,
Speaker 2: which is crazy. We could have invested in ventilation systems
Speaker 2: in schools and other places. We could have had ultifilet
Speaker 2: light in places where ventilation wasn't a good solution. I mean,
Speaker 2: you know, these advocates of airborne disease that they were
Speaker 2: saying in the summer of twenty twenty, like, we can
Speaker 2: get kids back in school this fall if we take
Speaker 2: airborne infection seriously, if every classroom has you know, at
Speaker 2: least an air purifier or something. But you know, the
Speaker 2: ventilation of schools, unfortunately, is terrible. So I think across
Speaker 2: the board a lot of lives would have been saved
Speaker 2: if we had immediately responded to COVID, recognizing the possibility
Speaker 2: that it was airborne and acting on that.
Speaker 1: Has this recognition that not only airborne transmission of COVID
Speaker 1: is a possibility, but just recognition of Wells's work overall.
Speaker 1: The Wells work has that kind of revitalized the field
Speaker 1: of aerobiology.
Speaker 2: Yes, it definitely has. And these scientists who felt like
Speaker 2: they were just shouting into the wind, forgive the pun
Speaker 2: they they really are trying to seize the moment our
Speaker 2: whole research centers being built to study airborne transmission, and
Speaker 2: they are trying to translate these findings into two real
Speaker 2: meaningful policy that can protect people not just from new
Speaker 2: diseases but from present ones. You know, measles, tuberculosis, influenza,
Speaker 2: chicken box, like, there are lots of diseases that can
Speaker 2: spread through the air at least to some degree. What
Speaker 2: it hasn't led to has been real mandates. Like there's
Speaker 2: no country anywhere yet that officially has standards in place,
Speaker 2: you know, like if you're going to build a building,
Speaker 2: this is what you have to do to keep the
Speaker 2: air safe. Doesn't exist yet. If you walk into a building,
Speaker 2: you kind of expect that, you know, there are building
Speaker 2: standards about the rebar and the materials that they're used.
Speaker 2: You know, you don't expect that they contain poisons that
Speaker 2: are going to walk through the air and kill you
Speaker 2: because there are standards, But there are no standards yet
Speaker 2: for how to keep the air clear of pathogens. They've
Speaker 2: suggested mandates, no one's taken them up quite yet.
Speaker 1: It'll be interesting to see what the future holds in
Speaker 1: that regard as long as people are allowed to continue
Speaker 1: to do basic research on this sort of thing.
Speaker 2: But which is an open question right now? An open question?
Speaker 1: Yeah, Well, I really enjoy chatting with you about this.
Speaker 1: I loved your book Airborne. Everyone go check it out,
Speaker 1: and thanks so much for taking the time to chat
Speaker 1: with me today.
Speaker 2: Thanks been real pleasure.
Speaker 1: Huge thanks again to Carl Zimmer for taking the time to.
Speaker 2: Chat with me.
Speaker 1: This was such an eye opening conversation. If you enjoyed
Speaker 1: today's episode and would like to learn more, check out
Speaker 1: our website this podcast will kill you dot com, or
Speaker 1: I'll post a link to where you can find Airborne,
Speaker 1: The Hidden History of the Life We Breathe, as well
Speaker 1: as a link to Carl's website where you can find
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Speaker 2: Foo