Athena (00:00:04): Have you been zombified by disease? Dave (00:00:07): Hopefully not Ebola. Athena (00:00:10): Or anything really. Dave (00:00:11): Maybe. Yeah. Maybe. Athena (00:00:14): Or the fear of disease? Dave (00:00:16): Oh, certainly. Um, yeah, the fear of disease, like, although not as much as my mom would like, she always wants me to get my flu shot and uh, then I don't, I just don't get it. [laughter] Athena (00:00:30): So according to your mom, you're not zombified enough by your fear of disease. Dave (00:00:33): Exactly, yes. So, which I guess increases the chances that I will be actually zombified by disease. Athena (00:00:39): Potentially. Potentially. Dave (00:00:40): Yeah, so- Athena (00:00:41): Welcome to the zombified podcast, your source for fresh brains. I'm your host, Athena Aktipis, psychology professor at ASU and chair of the zombie apocalypse medicine Alliance. Dave (00:00:53): And I'm your co-host Dave Lundberg-Kenrick media outreach program manager at Arizona State University. Athena (00:01:00): And we love brains. Dave (00:01:01): We love brains, not so keen on disease. Maybe. Athena (00:01:05): Yeah, we can do without disease. [Dave agrees] This episode is about disease. Epidemics. Dave (00:01:14): That's right. Athena (00:01:14): Bats spreading disease. Dave (00:01:16): Yeah. And a lot of really interesting history about how disease spreads from one place to another. [Athena agrees] And so who are we talking to today? Athena (00:01:25): We are talking with David Quammen, who is a journalist science writer and he's kind of an adventurer. He's been like all over the place studying disease and human animal interactions. [Dave agrees] And he's got a really interesting perspective on not just the sort of negative side of transmission, but there's also a positive side of transmission, that you can have organisms actually sort of sharing genes with each other. You know, bacteria sharing genes with each other. You're going to have organisms taking up genes from one another. Even our very existence as eukaryotic organisms is because of cooperation, or maybe not cooperation, we don't really know. But we basically took on what were previously bacterial cells free living and they are, what our mitochondria are now. Dave (00:02:20): It's a very heartwarming episode. [laughter] Athena (00:02:22): It is. Yeah. And we, we recorded this, um, before the coronavirus outbreak. Dave (00:02:30): That's true. Athena (00:02:31): And so there's some things in this episode that I think are relevant to understanding that, but you also need to know that it was before coronavirus. That's why we're not talking about it at all in this episode. [Dave agrees] Well, let's hear from this week's fresh brain. David Quammen. Dave (00:02:48): Sounds good. Intro (00:02:49): [Psychological by Temi] Athena (00:03:25): Welcome. David, would you, uh- David (00:03:28): Thank you! Athena (00:03:28): Introduce yourself in your own words for us? David (00:03:31): I'm David Quammen, I'm just in from Bozeman, Montana. I'm a science journalist and author of books mostly about biological sciences for the general public. Athena (00:03:41): Awesome. And as we just discovered, as we were getting ready here, you, Dave, are also from Bozeman, but not recently. Dave (00:03:50): That's right. I was, I was born in Bozeman and then, and then I moved here. So, uh, the opposite of Sam McGee from Tennessee. David (00:03:57): Sam McGee was from Tennessee where the cotton blooms and blows. Why he left his home in the South to roam around the pole. God only knows. [Athena laughs] Dave (00:04:05): I went the opposite way, see. So this is the first time in my life I've ever been cold, so when I'm laid in the ground, I'd be the opposite. David (00:04:13): Well, that's what that's uh say, Bozeman is a cold place. Nobody, you know, nobody would want to live there. It's, here we are on November 11th, I flew out on the 10th we'd had snow on the ground for three or four weeks. It's a miserable cold, frigid place. Dave (00:04:31): I was born, I was born August 30th and my mom said it was snowing the day I was born. David (00:04:35): There you go. There you go, listeners. August 30th: snowing in Bozeman. Athena (00:04:41): So, so, so David, well first of all we have Dave and David so to Dave, my cohost- Dave (00:04:46): Uh huh, yes [laughs] David (00:04:46): and then David, our guest, just so that we all are, are on the same page. So, so David, how did you get into science journalism and, and in particular, you know, these questions about evolution and disease and um, you know, things that are close to our zombie hearts. David (00:05:07): I drifted sideways into science journalism. I started my writing career as a fiction writer. I published a novel when I was fresh out of college back in 1970. 49 years ago, I published my first book and then I paid my dues between my first book and my second rather than the usual, which is pay your dues before your first book. So for 13 years I didn't publish much of anything else. I was a bartender and a waiter and a fishing guide in Montana. Athena (00:05:37): That sounds not so bad. [Athena laughs] David (00:05:39): There are worse things, and this is a good time. This is in the 70s. And um, I started reading nonfiction, uh, more intently than I ever had. Discovering that nonfiction can be imaginative and artful without cooking any of the facts, without, inventing quotes or anything like that. Straight, careful, responsible, accurate nonfiction can also be artful. I learned that from reading McPhee, and Stephen Jay Gould, and Annie Dillard, and Lauren Isley, and J.B.S. Haldane, and a number of other people. And then I said, hey, uh, yeah, that's the kind of writing I'd like to do. So I... reinvented myself as a magazine writer, uh, focusing on the natural world, figured out how to be a freelance magazine writer and then eventually started writing books about natural science as well--about Darwin, about evolutionary biology, about island biogeography, and then eventually about life science, things that don't take place mostly outside, but some of them take place inside, in laboratories, like molecular phylogenetics and... Athena (00:06:55): Awesome. David (00:06:56): Uh, evolutionary oncology. Athena (00:06:58): Yeah. So, so for you it was sort of like this realization that science and reality doesn't have to be deathly boring. David (00:07:06): Exactly. Yes. Not only does it not have to be deathly boring, but you can, you can thrive as a writer and get great satisfaction creating artful non-fictions that present complicated scientific facts, theories, and ideas in a way that's narratively dramatic and satisfying. People want to read about people. So when people read about science, part of them really wants to read about human stories of doing science, of science as a process, of science as a human activity. And I figured that out fairly early and that's what I've been doing since. I've been writing about natural science, but equally writing about natural scientists and writing about the history of science, especially the history of evolutionary, all the, all the branches of evolutionary biology. Because evolution, after all, is a historical discipline. If people are going to understand evolutionary biology, it seems to me logical that they should understand the history to some extent of evolutionary biology and have all these great discoveries. Athena (00:08:17): Well in some of your work also is about human-animal interactions, which is something that I think people are very interested in. Right? Both in its the positive sides of it and the potential risks. David (00:08:30): Yeah. A lot of my work is about human-animal interactions. I mean the book "Spillover" published in 2012 is about zoonotic diseases, meaning the, um, the infectious agents that pass from nonhuman animals into humans and become human epidemics and pandemics. Ebola, SARS, HIV, and some other fascinating viruses in particular that most people haven't heard of. Dramatic stories of, um, lethal emerging viruses coming out of nonhuman animal hosts and getting into humans. [Athena agrees] But some of my earlier writing before that too was about animal-human interactions. I wrote a book about big predators, um, in particular, uh, the relationship- relationships between rural people who live on the landscape and the big predators that we all want to see preserved: tigers, lions, crocodiles, Brown bears. That's a book called "Monster of God." Athena (00:09:33): Interesting. Cool. Dave (00:09:34): And what is it? Give us the sort of brief rundown of the dynamic between the people and the animals? David (00:09:43): Well, I focused on, in particular, those big predators that are big enough, fierce enough, and solitary enough such that a single individual can and sometimes does kill and eat a human. So what are loosely called man-eaters, [Athena laughs] that's the really not a very good term because most of those big predators that occasionally kill a human do not make a living preying on humans. If they do it occasionally when they have broken teeth, they're desperate. Um, or when their natural- Athena (00:10:16): Is it because we're not that tasty to them? David (00:10:17): No, because we're dangerous and troublesome. [Dave laughs] Athena (00:10:20): Oh, okay. So we are tasty. We're just a lot of trouble. David (00:10:22): I think we're as tasty as the next mammal. [everyone laughs] Maybe not. I don't know. But, um, what happens is that if you have a population of big predators, tigers, lions, uh, they're- they have their prey base. They're living on antelope or deer or whatever. They're the native herbivores. And if human population starts to grow, just even rural people and um, and they have livestock, they have goats and sheep and cows, then those goats and sheep and cows are competing against the wild herbivores. And the people don't like the wild herbivores because they're competing for grass with their livestock. So they tend to kill the wild herbivores for meat or displace the wild herbivores. If you still have big predators there and their wild herbivores are gone. What are they going to do? They're going to eat the domestic herbivores that have replaced them. So they eat cows, sheep, goats. People want to protect their cows, sheep and goats. Boom. Animal-human conflict. People against big predators. So the most natural and inevitable thing in the world. Athena (00:11:33): Hmm. Yeah. That's a great summary of what is a really complicated situation and I'm sure the human side of it and the politics- David (00:11:42): And I focused in particular on four populations of big predators around the world and on the people, the rural people who live on the ground amid those big predators who pay the costs for those big predators. We all enjoy the benefit of knowing that the Siberian tiger is still alive in the Russian far East, that the saltwater crocodile is still alive in Northern Australia, that the Asiatic lion has survived in Western India, in the state of Gujarat. The Asiatic lion, not tiger in India, and that Brown bears, which we call Grizzlies in Montana, but you're, that the Brown bear is a whole Arctic species that lives all the way around the North. I went to Romania and studied their Brown bear population there. Each of those big predators shares the landscape with rural people who are mostly poor and disempowered and raising livestock in the landscape and they are paying the costs of those big predators while the rest of us around the world enjoy the benefits of knowing that those big predators survived. Athena (00:12:51): Hmm. Interesting. Yeah. Well, so maybe this is a great, um, way to start talking about some of those smaller predators that come in at this intersection with sort of human agriculture and wild populations. Um, maybe could you tell us a little bit about like the, the Hendra virus? David (00:13:11): Mmhmm. Hendra virus is the case that I described at the very beginning of the book "Spillover." 1994, in a suburb of uh, oh, in the suburb of Brisbane, Australia, called Hendra - name of the suburb. It's a racing community, lots of race horses, thoroughbred race, horses in stables, there, lots of race tracks. It's a culture of racing. And in one stable, uh, all of a sudden in 1994, horses started dying, foaming at the mouth, convulsing, thrashing on the ground. Three men were there trying to save these horses, trying to clear their windpipes. Um, there was, um, a stable hand, a veterinarian and the owner of the stables, these three guys, and they worked with these horses and they, nobody knew what was causing, um, this terrible phenomenon, disease that was passing from one horse to another. But horses were dying. Something like 12 horses died in three or four days and these guys were working to try and save them. And then these guys, two of the three got sick, the stable hand went home, feeling like he had a terrible, terrible flu and the stable owner went into the hospital with severe respiratory problems and then organ failure. He died. Stable foreman recovered. The veterinarian is the one who told me the story years later. What they discovered was this was a new virus that was infecting these horses and it was similar to measles. It was an orthomyxovirus, I think, orthomyxovirus, I'm forgetting the family name, anyway related to measles. And uh, but it was never seen by science before and they named it after this suburb Hendra and then they tried to figure out where did this virus come from all over the bloody sudden hell? Um, and one fellow named Hume Field, who was a veterinarian who was getting a PhD in ecology, decided to make that his project to find the natural host, the reservoir host of this virus. What animal was it living in before it got into the horses? Athena (00:15:32): Yes. Can we maybe just take a minute to talk about this idea of a natural host or reservoir hosts? Like what that means exactly. David (00:15:38): Yeah. So virus can only replicate inside living cells. Virus is not a cellular form of life. It's kind of halfway between life and non-life. It's sort of this weird mechanical thing, a virus. But to replicate it must be inside a living human cell. Therefore it must be inside some kind of an animal plant or some other creature, could be inside of bacteria even. Um, but when you- when you talk about emerging viruses that infect humans in each case, that virus seems to come out of nowhere. If it's a new virus, suddenly it's in humans, but it can't come out of nowhere. It has to come out of somewhere. Um, there's a section in my book "Spillover" titled "Everything Comes from Somewhere." Athena (00:16:22): Mhm, so natural population or reservoir... David (00:16:25): So the reservoir host is the, um, is the species of creature and usually it's an animal in which the virus lives chronically, permanently, inconspicuously without causing disease in that particular species of creature. Athena (00:16:42): So it's a little, I don't know, for me it's a little confusing to wrap my mind around. Like it's the, you know, natural host quote for the virus. But then in that host, it doesn't even really manifest as an illness. Right? It's like, it's almost like it's- David (00:16:55): Generally not as far as we can tell. Athena (00:16:57): Yeah. David (00:16:57): It doesn't cause massive die-offs. Um, it lives there inconspicuously and permanently. That's it's refuge. Uh, and it has presumably evolved to some sort of an of an equilibrium, a standoff, an understanding with that species so that it, um, it in generally in the reservoir hosted exists at low levels, not concentrated virus, you know, not high viremium, meaning the blood is seething with viruses. It's just there and then it drips out of that host or spills over. [Athena mmhm] It's my title from that host. And if it gets into another creature, a horse or a human, then in some cases it can cause fulminating disease, um, sickness and death. And so this virus had spilled over from something, got into horses, horses turned out to be hugely susceptible to this virus. So they were dying and they were producing a lot of, um, you know, discharge, foam, um, bloody snot, all sorts of things. And that got on the arms of the guys. They're reaching down the throats of these horses trying to clear their windpipe, exposing themselves. They didn't know that this was a new virus and two out of three got sick. One out of three died. That's, that's Hendra. Athena (00:18:20): And then this relates to the idea of an amplifier, right? David (00:18:24): Yes. Um, the horses were considered amplifier hosts, but the, the term- Dave (00:18:27): What is- David (00:18:27): The term amplifier is kind of anthropocentric. I mean, if you're a horse, horses are not an amplifier host. Horses are the victims of this virus. If you're humans and you're getting it from horses, then you call them the amplifier host. Dave (00:18:42): So the amplifier host, that's the host where it goes from sort of not causing a lot of symptoms to causing a lot of symptoms? David (00:18:50): And just producing a lot more virus. It's virus is replicating more abundantly in the amplifier host. Dave (00:18:56): So, so you were saying, you were talking about the reservoir hosts, are we reservoir hosts to viruses? David (00:19:02): Um, we probably are, let's see, what would be an example? Um, there are probably, um, yeah, if you're a mountain gorilla and human tourists come and one of them is carrying measles, but that person, you know, has been vaccinated against measles, but he's somehow he's been exposed to measles and he still, you know, is carrying a little bit of measles virus and that person sneezes on you and you're a mountain gorilla and you die of measles. Then the human was a reservoir host. Dave (00:19:37): Okay. Athena (00:19:38): Yeah, which- David (00:19:38): But- Athena (00:19:38): -brings up this sort of interesting issue of like the different susceptibility, of different mammals. [David agrees] Right? David (00:19:45): Even what I said there is not fully accurate because I mean, a reservoir host as it's classically understood. It's an ecological term. It's not, you know, it's got slightly fuzzy boundaries, a reservoir host, but generally it means that this is the species in which the virus is living constantly. Dave (00:20:03): Right. So it wouldn't necessarily be like measles because measles, David (00:20:05): because measles circulates, measles does not. [Dave agrees] Yeah. Measles either make, makes you sick pretty soon or it's gone. Dave (00:20:14): Uh huh. So then, so then this student set out to find out... David (00:20:18): Yeah. So this fellow human field set. And so he started, um, he started collecting and sampling all the creatures that lived around these stables. Rats, no sign of the virus, lizards, no sign of the virus, no, uh, uh, possums, uh, no sign of the virus. Um, and then he noticed that the first horse, this was a little mystery story and the people who study emerging diseases essentially are, you know, are disease detectives. So he noticed the fact that the very first horse that got sick had not been in those stables. She was a mare who had been out in a, in a paddock field because she was with foal, she was getting ready to give birth. She was out there, but she got very sick. And so he brought her into his stables and then she died and she made all the others [Dave "uh-huh"]. So her name was drama series, kind of a appropriate name [Athena and Dave laugh] because she generated a drama series. So drama series had been out in this paddock. This is some tropical Australia. It's sunny, it's hot, you know, it's like Tempe [Dave "sure" Athena and Dave laugh], like Phoenix in the summer. Um, and there was one tree out in this field that threw some shade. And so this horse drama series would go under that tree and hang out in the shade. And this guy went back to that paddock. Um, and he looked at it and he saw this one tree, and then he saw bats flying in and out of that tree because it was a fig tree. Hmm. Ooh... [Athena laughs] Athena (00:21:49): Ding ding ding ding ding! David (00:21:54): So he caught some of these big Australian fruit bats. And he'd sampled them. Bingo. He found the virus. Dave (00:22:00): Huh. David (00:22:00): So that was identified as the reservoir host, this big fruit bat, I forget the species name of it. Athena (00:22:08): So it was the horse probably like eating the figs and they had the bat shit on them [David "exactly"] and it made her bat shit crazy. David (00:22:16): Hypothetically. Yes, exactly that. Yeah. Uh, so that's the sort of disease detection that goes on wherever new diseases are emerging, especially new viral diseases. Ebola, what's for for years. I think this mystery now has been officially solved, but for years, people you know, were terrified of Ebola, knew Ebola could be a terrible virus, kill 60, 70% of the people that it infects and these outbreaks would occur including the big 2014 outbreak in West Africa, which was not an outbreak, it was, it was an epidemic. It was more than an outbreak. Um, uh, and people did not know what the reservoir host of Ebola was. People said, well, we think it's bats. Bats are the reservoir hosts in a lot of these cases, but there was no smoking gun. There was not the gold standard of proof that it was bats. The gold standard of proof is not that you take an animal and you sample it and you find antibodies in its blood against this virus. That might just indicate exposure. If you find live virus, if you can take a blood sample and you can grow live Ebola virus in the lab from the blood of that animal, then you have shown that that animal was a reservoir host. Athena (00:23:31): Yeah. Can we talk about this sort of finding the antibodies and what that means? 'Cause I think that's like just a big picture issue with, you know, detecting disease that's interesting, right? That like you don't actually have to find the live virus in order to know that this species is affected. [David agrees] Yeah. David (00:23:49): If you find antibodies and there are several different kinds of, of tests where you can, in the lab you can, you can test to see if there are antibodies against this particular virus. Um. Athena (00:24:02): And that those would be there because- David (00:24:04): One of them's called Western blot. Athena (00:24:04): -the immune system detected that virus in that host. Right? And then produce these antibodies [David agrees] to try to fight it off and those will stay in the host pretty much indefinitely- David (00:24:16): And those will stay. It's part of the adaptive immune system. Right- Athena (00:24:16): So you can, yeah. So, so it's kind of cool actually that we can take the way that the immune system is working and use that for clues about the direct, you know, the, the path that a disease has taken through the web of life. David (00:24:32): It's sort of another kind of molecular fossil record. [Athena agrees] Dave (00:24:35): So once we figured that out, what, how does discovering what the reservoir host is? How does that help us? You know what I mean? Like- David (00:24:44): If you discover the reservoir host of a terrible new virus is animal A, then uh, some people, some people say, well, that's going to be bad to know because then people were going to say, okay, um- Dave (00:24:59): Eliminate- David (00:25:00): Fruit eating bat A is the reservoir host of Hendra or Ebola. Therefore, what's the logical conclusion, well we got to kill off, we've got to exterminate that animal. No wrong. No. The logical conclusion is we've got to keep humans and animal A separate. We've got to keep humans from hunting animal A for food, keep humans from killing 10 of these giant bats and carrying them into, to market over their shoulder and then carrying the little daughter over the same shoulder when they walk back from the market. Dave (00:25:36): Right, okay. David (00:25:36): Um, you got to do that sort of thing. Leave the bats alone. We need bats. Bats are wonderful creatures. They have huge, uh, importance. They deliver a lots of ecological services. The world doesn't have enough bats. We need all the bats we have, but keep humans and bats from having contact insofar as possible. Athena (00:25:56): Yeah. So I think there's a whole interesting set of issues too about like why is it that bats are often such a problematic species for us, right? In terms of, yeah- David (00:26:08): Yes. Because if you, if you make a Rogue's gallery list of new dangerous emerging viruses - SARS, MIRVs, Hendra, Nipah in Malaysia, in Bangladesh, a Marburg virus in central Africa, and now Ebola and a number of others. And you say, what are the reservoir hosts of these? A lot of them will turn out to be bats. And this is a question that science has, scientists who work on this is grappling with. Why bats? And I asked those scientists, I went to them when I was researching "Spillover." Why bats? There's a wonderful scientist in Fort Collins named Charlie Calisher, who has worked on these viruses. He's become a pal of mine. And, uh, Charlie wrote a paper on the subject why bats, uh, and, uh, looked at a number of different hypotheses and looked at the data that were available. Not as much data as we wish, but a lot. And there are a couple of things that can be said. First of all, do bats seem to be disproportionately represented as reservoir hosts of dangerous viruses? Yes. At first blush, they do seem to be disproportionately represented, but then you remember one in every five species of mammal on planet earth is a bat. Athena (00:27:21): Oh. [Athena laughs] David (00:27:23): Yeah, yeah. Bats are extraordinarily diverse. There's something like, I think it's 1200 species of bats, something like that. Maybe 6,000 species of mammals. I may have those numbers wrong. This is just off the top of my head. But, and you know, this book was published seven years ago, but I think it's about that. Bats are disproportionately represented in the diversity of mammals on earth. So, uh, that's one thing. The other thing is that bats tend to live a long time. You know, a little bat size of a mouse can live 20 years. A mouse is not going to live 20 years. Dave (00:27:58): So does that give the disease more time to... David (00:28:00): Yes. And bats live in the, at least some live in huge social aggregations. So, you know, I've walked into a cave with um, with the, uh, research a couple of researchers and we've seen um, uh, an aggregation of bats on a wall looked like somebody had put up like a big Buffalo robe on the wall, but what it was was 60,000 bats. Athena (00:28:25): Oh my gosh. David (00:28:26): Uh, all huddled together, keeping one another warm, their babies, their pups under their arms. Athena (00:28:33): That's like the size of the undergrad population on this campus. David (00:28:37): Yeah. Oh, yeah. Dave (00:28:39): Right. That's a lot. Athena (00:28:39): 60,000, like that's a lot of mammals all together- David (00:28:43): Yeah. So, um, they live a long time. They live closely jammed together. Both of those, um, represent good opportunities for viruses to be passed from one to the other. There is also some evidence that they down-regulate their immune systems during the, if the, if they're hibernating bats- Athena (00:29:03): Oh... David (00:29:04): During the period of hibernation. Dave (00:29:06): Just explain what down regulating the immune system, what that means and what that involves. David (00:29:12): Um, I'm going to get it wrong if I go into any sort of molecular detail. Athena (00:29:17): Yeah we don't need to go into that [laughter] Dave (00:29:18): But the basic idea is just they stopped allocating resources to the immune system [David "right" ]while they're hibernating. David (00:29:23): Yeah. And they're, you know, much more specific molecular and cellular explanations for how that works. You know, the MHC complex of genes, um, decides to, you know, produce, um, immune cells that are not as aggressively. I don't know. Dave (00:29:41): Sure if that's, I just needed the broad- [Athena and David agree] Athena (00:29:45): Okay. So there, so Dave (00:29:47): I have one more, like just clarifying question from earlier. Ebola, did it turn out it was bats? David (00:29:52): Well, I'm told I missed this paper when it came out, but I'm told that there was a paper published in January of this year that had the gold standard of proof for at least one of the quote on quote species of Ebola virus. And I think it was the most infamous one, which is the Ebola Zaire, that they had found live virus in the species of African, I think it was a fruit bat. There are big bats and little bats. Big bats eat fruit, little bats eat insects, um, macro bats and micro bats. Uh, and I think it was a macro bat central African macro bat. But I haven't seen the paper. I need to go back to look at that. But until that point, people, everybody was saying, people were saying that's, oh sure, bats are the reservoir host. But the Ebola experts that I've talked to, and I did an article on this very subject for national geographic in 2014, they were saying, no, no, we don't know. We don't know that for sure yet. That's a supposition as of now, it's apparently, I think more than a supposition. Dave (00:30:53): Hmm. Okay. Athena (00:30:54): So in terms of the bats and why they're an issue, it seems like there's, there's two other things that are, are just like very, um, just big picture. One is they're mammals, right? [David agrees] So in terms of for humans, right, they're going to be the viruses that can proliferate in them are probably going to be more similar to those that can proliferate in non-mammals. David (00:31:15): Yes. As a first take generalization, that's correct. Athena (00:31:18): Yeah. And then there's the fact that they fly all over the place, right? So their geographic range... David (00:31:24): They operate in three dimensions, not just geographic range in two dimensions, but the third dimension. Um, so they occupy a lot of space. That doesn't necessarily mean that they come into contact with humans in three dimensions except when we shoot them out of the sky. Athena (00:31:41): Uh huh. If they're like interacting with, you know, livestock or animals, right. Like they can potentially get from one place to another faster than like a rat might be able to. David (00:31:51): Yes. That's right. Yeah. They cover more. They cover more ground. That's correct. [Athena agrees]. Dave (00:31:59): Interesting. And then in terms of the transmission from bats to us, is that like you were saying that you thought it might've been from eating something that was covered in... Athena (00:32:07): Batshit. David (00:32:07): Well, yeah, I mean that's, um, they can shed virus in their feces, in their urine. [Dave agrees] Oh yeah. Probably also in saliva, depending on the virus. Um- Dave (00:32:19): So if we're eating some fruit that they've taken a bite out of, we could also, theoretically... David (00:32:22): Yeah, theoretically. Yeah. Right. I mean, there's this other case that I described in spillover of a Nipah virus in Bangladesh, uh, which began, was first recognized in Malaysia and that involved pigs as an intermediary. It was a virus. It turns out that it was also a bat-born virus in a particular group of giant fruit bats. Um, and on Peninsular Malaysia, there are these big pig farms- there were in Malaysia and, um, a lot of land has been cleared and they were producing thousands and thousands of pigs. And then the pigs started getting sick and dying, coughing, you know, showing this, this infection that was passing from one to another and passing from one pig farm to another. You could hear it coming from over the Hill. They, they said these pigs had had a one mile cough. You could hear this- Athena (00:33:11): What? David (00:33:11): -this coming. Yeah. Yeah. Athena (00:33:13): That's crazy. David (00:33:14): Yeah, it's scary. [Athena laughs] So it was a big problem all of a sudden. And then, and then pig workers started getting sick. Um, people who worked in the abattoirs, butchers, you know, meat sellers, they started getting sick and dying. This virus was identified, that was given the name, Nipah, N-I-P-A-H, named after little village in Malaysia where it was first identified, and it was found that what had happened was that, um, uh, these piggeries existed in the sun. But then the people who ran them started planting fruit trees like mango trees and I think starfruit trees, um, shading these piggeries and they had another, another income source, another income stream cause they were harvesting the fruit. Meanwhile, peninsula Malaysia is getting deforested, losing its native forest. It's got these big fruit bats that are used to flying around in the native forest eating the fruit. Now the native forest is disappearing, but there are these orchards. So they go to the orchards, they start eating the mangoes and the starfruit. Athena (00:34:18): It's the same story as with the predators. David (00:34:18): And yes, and there they are. And where are they shitting? Well they're shitting Like rain down onto the pigs. The pigs are eating everything that falls fruit, pulp, um, you know, mud, whatever. And I don't want to be too hard on pigs. They're eating, you know, strip up in the things. So the pigs get infected because the bats are raining virus down on them. Dave (00:34:38): Oh wow. David (00:34:38): This was figured out. And so, and then people were getting sick and people were dying of this virus. And in Bangladesh there's a different story of how it transfers. Same virus, same reservoir, host of a bat. Um, but a different story in Bangladesh. Okay. Bangladesh does not have big pig farms because Bangladesh is Muslim. [Dave agrees] Please forgive me, Bangladeshis out there, if I'm getting any of this wrong. It's a nice country and I had a good time researching there. Uh, um, and uh, but people were showing up sick with this virus there with Nipah virus. What's happening? Well, it's a tradition in Bangladesh to drink fresh date palm sap when the date palm sap is running, and there are tappers who climb up the date Palm trees and they cut slashes and they put pots to collect the sap. Just the way people collect maple syrup in Vermont. And then they, and they leave it up there all night, this little red clay pot and climb down, uh, in the morning and they've got a clay pot full of this nice fresh date palm sap. And they sell it like from a lemonade stand on the corner. Fresh sap. Some people also, um, boil it and reduce it, um, and turn it into kind of molasses cause it's sugary. But if you sell it fresh, people say, wow, this is fresh date palm sap, this is great, but what's happening- Athena (00:35:57): This is healthy and natural. [laughter] David (00:35:58): They've got this pot up there all night and the bats are coming to eat the date Palm dates and they're pissing and shitting in the, into the pot, into the day pong. [laughter] This is, am I allowed to use this vocabulary? Athena (00:36:10): Oh yes. Yes, yes. [laughter] David (00:36:15): And so they're contaminating, date palm sap. People were selling it fresh on the street and uh, the people who buy it are getting Nipah virus and getting very sick and some of them dying. That's the mechanism in Bangladesh as opposed to in Malaysia where they've got all the pigs. Dave (00:36:29): It is pretty interesting though, this idea of, you know, us getting these diseases. I actually had never known that bats were such a major disease- David (00:36:39): You know, in this book. I've got it. Are we on, are we rolling? We're rolling. So, uh, in this book I've got about 110-120 page chapter devoted to the ecological origins of HIV, which has also been published separately as a short book with a new introduction called the Chimp in the river. And it's just dizziyngly counter-intuitive. It's so different from what we think we know about the origins of the AIDS pandemic. Dave (00:37:04): Really? So what's the, what's the real story? David (00:37:07): Um, this is reconstructed by me from the work of a number of scientists, particularly um, Beatrice Han, then at the university of Alabama and her group and Michael Warby still at, um, University of Arizona down in Tucson. [Dave agrees] And they figured out using molecular evidence that the origins of the pandemic strain of HIV, which is HIV one group M, we're in the Southeastern corner of Cameroon in central Africa in 1908, give or take a margin of error. Athena (00:37:45): Seriously that long ago? David (00:37:46): When a single chimpanzee had blood to blood contact with a single human being [Athena and Dave "wow"] and that human being became the real patient zero. Dave (00:37:56): In 1908? David (00:37:57): Give or take a margin of error. Athena (00:38:01): Yes, so who, what's known about that? What happened then? David (00:38:03): Well, we don't know. We don't know. But somehow that, um, that virus, having found its way into a human, discovered that it could exist in replicate, uh, and thrive pretty well in humans. So it was passed from human to human and the probably in the headwaters of the, um, Ngoko River, which leads to the, uh, Tsonga which leads to the mainstem Congo at a place called Brazzaville, which is right across the river from a place that was then called Leopoldville, the two biggest colonial towns then in central Africa. Um, it might've taken 20 or 30 years to pass from human to human in the villages, slowly and work its way down river. And it got to Brazzaville and Leopoldville, um, and Leopoldville became Kinshasa at independence. Um, but back in, um, before independence. And that roughly the time of independence. Leopoldville for instance, had, um, at a hospital for people with venereal diseases. And there was, there were a lot of what they called femme libre, free - femme libre, free women who essentially were sex workers who were also, um, cooks and companions and laundresses and might have four or five. These were essentially men's labor camps, Brazzaville and Leopoldville in those days, Athena (00:39:41): Wellingly named free women. David (00:39:43): Yeah, yeah. Right, right. [Athena laughs] Yeah, yeah. That's what the French called them because supposedly they were, you know, their morals were loose, [Athena laughs] but of course their morals were no looser than their clients' morals or less so. Anyway, that's what they were called. Yeah. And it is an ironic, sort of- Dave (00:40:00): So they were working, so they're working at these men's labor camps where there's a lot of them. David (00:40:05): So they're having contact with men and occasionally if they have, um, uh, if they have a, um, a manifesting venereal disease, you know, syphilis or gonorrhea, they would go into this clinic where the clinic would treat them with hypodermic needles that were non-disposable that they would rinse in distilled water between injections. Dave (00:40:27): Okay. Athena (00:40:28): Wow. David (00:40:28): And this was also going on in, um, that was in what then was Belgian Congo, uh, Leopoldville Congo. Dave (00:40:36): So when is this about like what... David (00:40:37): This was, this was like from the 1920s until independence in around 1960. Um, there was a fellow in French Congo, which is now, um, the Republic of Congo of which the capital is Brazzaville North of the Congo river. There was a doctor there who traveled around during the 1920s and thirties, vaccinating people against, um, if I recall correctly, again, this is seven years ago since, you know, I've really talked about this book, vaccinating people against problems like Malaria and, uh, just a semiosis and he had something like six hypodermic syringes- Dave (00:41:17): Gosh. David (00:41:17): -precision medical instruments probably made in France or Germany. And with those six hypodermics, he vaccinated something like 5,000 people. Dave (00:41:28): Wow. David (00:41:28): Going from town to town. Now, this is not proven, but this is hypothesized to be part of what jump-started the transmissibility of HIV virus from one human to another. And eventually, uh, that became unnecessary because sexual contact became relatively efficient as a way of, I mean, that had always been presumably part of it before the hypodermic needles, you know, the people in the villages of Southeastern Cameron and, um, it passed slowly, but steadily through sexual contact. And then according to the thinkings of some writers, including a fellow named Jacques Pepin, who's written an important book called the origins of AIDS. Um, there was this fellow doing all this vaccinating that probably helped to jumpstart it. And then this, um, this medical clinic in Leopoldville was doing the same sort of thing. Athena (00:42:28): And I mean, if that is a part of the, you know, history of this virus, then there's actually been selection pressures for it to be good at transmitting through hypodermic needles. David (00:42:41): Yes, that's right. That's right. Athena (00:42:44): So- David (00:42:45): Yeah so it's not a surprise that it still does it. [Athena agrees] Yeah. Of course transmitting through a hypodermic needle is a whole lot easier than transmitting through sexual contact. If it's a, you know, if it's a bloodborne virus. Uh, how did it get to America? You might ask. Dave (00:43:03): Yeah. Athena (00:43:03): Yes, how did it get to America, David? David (00:43:03): If you're as old as I am, you remember that when, when AIDS first loomed on the screen in 1980 and 1981 and it was mysterious and terrifying and, um, and lethal, one of the things that people thought they knew about it was that it affected, um, hemophiliacs. And, uh, men who had sex with men, uh, and Haitians, that was part of it. Haitians, that was part of the early risk groups. People were turning up with the first cases, those three groups of people. So, so scientists were trying to make sense of that pattern. Men who have sex with men, hemophiliacs, Haitians. Okay, here's, here's Jacque Pepin's explanation for that, which I, um, amplified in my book, um, in, uh, in 1959, 1960, uh, the Belgian Congo was rumbling with readiness for independence and it was a wonderful leader named Patrice Lumumba. Uh, and he was assassinated. Um, and all the Belgians left with independence in 1960. Um, the Congolese essentially said, get out of here. You Belgians, you know, go back where you came from, to Belgium. And they left and they threw out all the, in getting rid of the Belgians, they got rid of the professional class. They got rid of the doctors, the lawyers, the clerks, um, the engineers, the teachers, and the Belgians had trained no to speak of no Congolese into those rules. So the Congo was left without a professional class. Big sprawling country. This big population. So they were in trouble. And, um, UNESCO said, uh, somebody needs to help the Congolese, please, let's get some professionals from somewhere and get them to come in and help the Congolese. Well, Haiti and a lot of French speaking, black, African by ethnic origin. People who were professionals, doctors, lawyers, clerks, engineers, teachers, and God bless them. They- lots of them. It was like the Peace Corps. They went to Congo and started filling this role. Dave (00:45:30): Wow. David (00:45:30): Haitians. And they lived there for five years, six years. And they had wives and girlfriends and some of them picked up this infection that now was in Kinshasa, as the city by now was known. And then, um, uh, what's his name? I'm forgetting the, the Congolese leader. Um, not Mugabi he was obviously in Zimbabwe. Oh. Mobutu. Mobutu Sese Seko, as he later called himself, uh, he became, um, leader, eventually dictator, Mobutu of the Congo. And he said, I'm going to, I'm going to make Congo more Congo. I'm going to get rid of all these outside influences. And he changed the name of the country to Zaire. And he had a program that was called Zairianization of Congo, meaning Congo for the Congolese. So now instead of getting rid of the Belgians, he got rid of the Haitians, kicked the Haitians out, they went back to Haiti, and they took the virus with them. Dave (00:46:38): Okay. Interesting. Athena (00:46:41): And then so making sense of this pattern with. David (00:46:44): Yes. And then the next thing, according to Jacques Pepin, and I think this is persuasive, um, in Haiti at that time in the late sixties now, there were plasmapheresis centers. There were places where you could go and sell the plasma from your blood for a good payoff. You know, go in there, let them draw two pints of blood, and they'd give you $6. But they don't keep the blood. They just want the plasma. So they circulate your blood through a plasmapheritic separator, and they take out only the liquids and they put the red blood cells back into you- Athena (00:47:29): Oh my gosh. David (00:47:29): Back into you so that then you can come back a week later and donate some more plasma. Right. Where does that plasma go? Athena (00:47:38): All this blood. David (00:47:38): It's owned by Americans and they're shipping that plasma to Miami where it goes to hospitals. Athena (00:47:46): Wow. David (00:47:46): Okay. Thousands of pints of blood are traveling from, from Haiti to the U.S. In the late sixties, early seventies. As this plasma-for-pay operation, they're importing it to the U.S. And what's happening? Well, you hook up Haitian A to this machine. You run his blood through the machine, you take out the plasma, he leaves, the Haitian B comes in, C, D, E, F, G. Their blood is all going through the same machine and it's all mixing. The plasma is all mixing. So one donator out of a hundred might be HIV positive and the yield of plasma is going to be HIV positive. Athena (00:48:30): Wow. David (00:48:32): And that goes to the U.S. Athena (00:48:34): Wow, and this is like a standard thing, right? Where they like, pool- David (00:48:38): Yeah. Athena (00:48:38): -blood before- David (00:48:40): That's right. It's pooled. Dave (00:48:41): Is this why the hemophiliacs ended up...? Donated blood- David (00:48:43): Yes. That's because they're getting, they're getting, um, some of this plasma for clotting factor. Dave (00:48:50): Okay. David (00:48:51): Right. So it shows up among haemophiliacs. It shows up among Haitians in Florida because they're migrating up from Florida. Um, and they're, some of them are bringing it with them. And, and then it shows up in, um, men who have sex with men. [Athena and Dave agree] Athena (00:49:11): Yeah well then- David (00:49:11): And so that's happening in 1980 or 81. Where did it begin? It began 1908, give or take a margin of error in the Southeastern corner of Cameroon when one guy, probably a guy, um, traps a chimpanzee in a snare for meat comes up, kills that chimpanzee with his machete, dismembers it, takes a couple of bloody arms to the market, gets blood somewhere on his arms. This is called the cut hunter hypothesis and it's, I believe it's Beatrice Hans' phrase, as I said she's one of the two people who led the work to untangle all this. She was the one using molecular evidence who placed the origin to the Southeastern corner of Cameroon. And Michael Warby with his group, placed the time to 1908, give or take a margin of error. Athena (00:50:04): Hmm, cool. [Dave laughs] Well, I mean, it's horrible, but like, uh, the detective story of it is really awesome. David (00:50:14): It's all ecology and evolutionary biology. Athena (00:50:16): Yeah, yeah. Speaking of which, can we talk about, um, this idea of heritability, like the infectious heritability idea...? Dave (00:50:27): Can I ask one question before we move on? [Athena and David agree] Athena (00:50:31): Yeah you're like still trying to metabolize this. [Athena laughs] Dave (00:50:32): So at this point, right. I know in America there's a lot of fear about things like getting vaccines and things like that from the injections. Do we take precautions to, right, cause I assume we don't, we don't reuse hypodermic needles, but this, this idea of this sort of plasma thing where they mix the blood. Are there, are there risks like that currently from, cause a lot of it sounds like a lot of this was transmitted by, you know what I mean? Athena (00:50:58): Hospital and medical- Dave (00:50:59): -hospital and medical procedures. And it's a little- David (00:51:02): These lessons have been learned by the medical community and the scientific community. Okay. They haven't yet been learned by the, the fearful public. Dave (00:51:13): Uh huh. David (00:51:13): So they're um, you know, 50 years ago, 60 years ago, um, there were legitimate concerns about blood plasma and, and even in some cases about vaccines, the scientists have been on this, they have learned the lessons and those, those products now are screened carefully. Dave (00:51:33): Okay. So the, when they, so now if you go in to get like a blood transfusion or whatever, they check. David (00:51:39): Yeah, yeah, that blood has been screened. But um, there are still there are paranoid stories about what happened. Even back in those days. There is a story, uh, I was talking with Athena and Carlo about this over lunch. There is, um, there's a 900 page book that was published by a fellow named Edward Hooper called "The River," which tells the story, his version of the story of the origins of AIDS. His version is different from the version I just told you because he wanted to believe based on some, I think 10 years evidence that, um, the AIDS pandemic was jump-started in Africa because someone, um, a fellow named Hillary Koprowski from the Wistar Institute in Philadelphia was testing an oral polio vaccine that was not made from monkey liver cells, but had been made from chimpanzee cells and that had supposedly picked up this other virus, HIV, uh, that has been investigated and thoroughly debunked. Uh, but this, this fellow continued arguing for a long time. Um, is it true? No, it's not true. Uh, I've read the whole book. I've talked to the, you know, and talk to and read the same sources. Um, no, we know that it wasn't true, but it scared people for awhile. Dave (00:53:04): So now, so now when we go in the U.S. They, they dispose needles, right? They use them one at a time. And now in Africa, when people are going, are they at, they switched to disposable needles? David (00:53:15): Um, that's a really good question. I mean, you know, there's an Ebola outbreak still going on in Western Democratic Republic of the Congo. [Dave agrees] Um, and they are desperately short of basic medical materials in some of these places, you know, examination gloves, syringes, um, those, the cost of a syringe, I don't know what it costs in a drug store in the U.S. Not very much. She can buy it. I don't know if you can buy syringes over the counter. Um, but the cost is trivial in the U.S. But those costs are not trivial if you, if you're in a village in central Africa. Dave (00:53:53): Sure. Athena (00:53:53): Yeah. David (00:53:54): So, so it's, that is a serious constraint. If you're a doctor trying to save people from Ebola in, uh, Eastern democratic Republic of Congo right now, today, November 11th, you probably are desperately short of various different medical material including syringes Athena (00:54:14): Hmm. you bring up. Also, another good point, Dave, which is just that this whole issue of the view of diseases and like medical treatment and all of that is such a rife, um, environment for conspiracy theories, right? Yeah. Like it's, [David agrees] and part of it is there's a lot of unknowns, right? And it's hard to piece together some of the stories, but then even when facts come to light, um, there's, you know, you might've figured out the actual biological virus, but the mimetic virus, right? David (00:54:48): Yeah, right. Yes. And it's always, and it's always yes. And it's always easier and more exciting to be paranoid and scared than it is to exercise due diligence, do the research and find out that yes, for this particular vaccination, your child is, you know, a thousand times more safe if she gets a flu vaccine, if she gets the basic, you know, going to school vaccines, MMR. And those kinds of things. Yes. Yes. Vaccination is one of- Athena (00:55:19): They save lots and lots of lives. [Athena laughs] David (00:55:20): It's, yeah, it's one of the, one of the foundation points of, of 21st century medicine. [Athena agrees] Dave (00:55:28): Yeah. No, but I could see like, so as some, I mean I've, I've vaccinated my kids, but I could see hearing this story like it's like, wow, there's a lot of steps of the story that involve well-meaning physicians sort of not realizing that they're helping to spread an epidemic. You know? And so I could definitely see how hearing the story, it's like, it's a little, it's scary. I could see how people are, are scared about the idea. I'm not saying- David (00:55:51): Yeah, people in Eastern Congo or, or you know, are scared and, and believe lots of various things about Ebola. Oh, they don't, they don't want their loved ones to go into the Ebola treatment centers because 60% of the people who go in there come out feet first. Sure. So, okay. So let's keep grandma at home instead when she starts suffering from Ebola. That doesn't work out so well either. Yeah. Athena (00:56:17): Yeah. I think, you know, that maybe there's this tendency to go into like a risk averse mode when you feel threatened, too. Right? And then maybe you're like overestimating, uh, the threat of various things. I'm- David (00:56:29): Sure, yeah. Of course. Athena (00:56:29): I'm just speculating here, but I think there might be some psychological issues, right? David (00:56:33): Yeah. They found that even, um, it was a doctors without borders did this study, I can't remember who did this study, but in the early Ebola treatment centers, um, they would bring people in to isolate them, get them the way away from the community so that they wouldn't continue to transmit the disease and then they would try to treat Ebola. Although there was no anti Ebola drug at that point. So they treated him with just basic life support, um, you know, fluids and, and antibiotics and things like that to protect them against secondary infections and then hope that the people could come through. But when they would go into the Ebola treatment center, it would go in behind these big plastic fences, opaque plastic fences, and then their loved ones wouldn't see them. They'd go in there and then they might come out alive and they might come out dead. They discovered that if you just made those fences out of mesh instead of out of solid plastic so that people could see what's going on in there, their doctors and nurses walking around trying to care of people, that that decreased the paranoia to no considerable- Athena (00:57:38): That's literally the transparency. David (00:57:39): Yes. Literally transparency helped. Athena (00:57:43): That is a really cool literal metaphor. It's not even a metaphor. It's a thing. Dave (00:57:48): Yeah. Actually. Athena (00:57:49): Yeah. I love that. Dave (00:57:50): That is interesting. Athena (00:57:51): Yeah. Cool. All right, so should we, I mean, I, so I want to talk about this like heritability thing, right? Because David (00:57:59): Infective heredity. Athena (00:58:00): Yes, that's right. Infective heredity, that the- David (00:58:00): The phrase that comes from the great Josh Lederberg, the great Josh Lederberg and the great Esther Lederberg. Athena (00:58:07): Yeah. So when do infections go from being something that just jump, um, you know, uh, horizontally from organism to organism and actually like become part of who we are? David (00:58:21): Yeah. So this is, this involves the phenomenon that's called horizontal gene transfer, which most people have never heard of, which I had never heard of until 2013 when I started reading about it. And that led me to write this book, the tangled tree, which is about the fact that the tree of life is a picture of evolutionary history is not a tree. It's a tangled tree, meaning that the branches don't all just diverge, diverge, diverge, leading up to little twigs and leaves. But some of the branches on the tree of life flow into other branches. They flow sideways horizontally. No real tree does that. Um, that's horizontal gene transfer. Um, this phenomenon discovered belatedly that, uh, when people started sequencing genomes, that genes sometimes move sideways from one species into another, even from one kingdom of life into another. Athena (00:59:16): And how on earth do they do that? David (00:59:16): How do they do that? [Athena laughs] Well, it was first discovered in bacteria, um, because bacteria, um, smooch, um, bacteria, you know, it's called the metaphor is bacterial sex. There's phenomenon called conjugation. I know, I'm telling you things that you know, but it's a phenomenon called conjugation, which is two bacteria, um, connect themselves by way of a tube. And then genes usually in the form of little circular genes, plasmids they call them, can pass from one bacterium into another one particle into another trading genes sideways. Horizontal gene transfer, that's called conjugation. Um, it's not really bacterial sex because it has nothing to do with reproduction. It's just transfer of genes. Athena (01:00:02): It's like there's any, each of the little text messages or something. Dave (01:00:05): Yeah. What is the why of it? Why does that happen? David (01:00:07): Uh, it happens, it happens because it can, and it happens because it's reinforced by natural selection. In some cases, those genes that are moving sideways carry, um, capacities that are highly useful for a new environment into which the bacteria may have just moved or found itself. Dave (01:00:28): Okay. Athena (01:00:28): So like a whole adaptation? Yeah. Can just be like, zip! David (01:00:32): so bacterial genomes, bacterial genomes are very economical and concise and small. They don't carry around everything they need, bacteria, but they have the ability to acquire tools on the fly, you know? Um, like a one bicycle racer throws a water bottle to another bicycle racer. Okay, that's conjugation. Dave (01:00:54): Okay. David (01:00:54): Now, um, except it's not throwing a water bottle. It's throwing a little plasma that has genes on. What might those genes do? One of the things they might do is confer resistance to penicillin. Suddenly bacteria number two acquires this gene from bacteria number one. So now bacteria number two is resistant to penicillin cause she's got a copy of this gene. Athena (01:01:16): Yeah, so- Dave (01:01:18): It's like the genetic equivalent of like watching a YouTube tutorial, right? David (01:01:22): That's exactly what it is. [laughter] I meant to say that. [Athena and Dave agree] Um, so that's one form of ineffective heredity. But now we learned that for instance, viruses, um, can do sort of a drag and drop thing. Athena (01:01:34): This thing about the, the um, that bacteria can share these, these resistance genes means that if you take antibiotics, um, then like if there's just some bacteria in your gut that have resistance to those antibiotics, they can then share the antibiotic resistance genes with other bacteria from other species in your gut. David (01:01:55): Yes, from species to species. Um, an E. coli can share a gene across to a salmonella and the salmonella can share it to a staphylococcus by this form of horizontal gene transfer. And that's why antibiotic resistant bacteria are such a global problem so quickly, [Athena agrees] not because of incremental point mutation that they're independently developing a resistance to antibiotics, but that once resistant or resistant gene is developed in bacterial species, a quote on quote species that can be passed instantaneously into a completely different kind of bacteria through horizontal gene transfer process. Dave (01:02:37): Wow. David (01:02:37): And therefore, um, antibiotic resistance has spread around the world like wildfire. Dave (01:02:46): That's wild. [Athena agrees] David (01:02:46): Uh, but viruses can pick up a piece of gene viruses, you know, get into a cell. They get into the nucleus, uh, at least in some cases they can pick up a piece of DNA from the nucleus of organism A and then the virus replicates with that new piece of DNA. The virus replicates spills out of that cell might infect another cell or it might leave that organism and infect another organism carrying that bit of DNA with it, delivering that bit of DNA into the genome of the other organisms. That's called transduction. Viruses carrying bits of DNA. Athena (01:03:26): Those can get into the germline? David (01:03:28): and that can get into the germline if they infect- Dave (01:03:31): What do you mean by germline? David (01:03:31): Germline cells, Athena (01:03:33): Yeah so the egg cells or sperm cells. [David agrees] Dave (01:03:35): So like- David (01:03:35): So they where the germ line is the permanent, continuous, um, chain of, of genome inheritance. Dave (01:03:43): So essentially like if I had this happen to me then, like- Athena (01:03:48): Your kids. Dave (01:03:48): Not the kids that I have now, but if I have- Athena (01:03:50): Future kids Dave (01:03:50): Future kids, then they might have, share- David (01:03:53): Yes. Okay. So now let's talk about endogenous retroviruses. Athena (01:03:57): Ooh, yes. [Athena laughs] David (01:03:59): Speaking of the germline. Um, a retrovirus is a virus that moves backwards from what you think of viruses infecting cells and replicating themselves and exploding the cell. And then there are more virus particles. A retrovirus inserts itself into the, into the nucleus of the cell that it infects and it inserts its DNA program into the genome of that cell. And then two things can happen. It can replicate itself in that cell and explode and lots of more retrovirus particles come out or it can just abide there while that cell lives, its life replicates itself. When it replicates itself, it replicates the, the retroviral genome that gets passed along and it just might pass pass along for awhile and then eventually bust out and express itself as viral particles. Okay. That's what happens with HIV, which is a retrovirus. It infects immune cells in just that way and some of them it, it explodes and lots more HIV particles come out and in others, it just divides there. And as the immune cell replicates itself, it replicates the viral DNA also with immune cells. But if it infects, if a retrovirus infects the germline, which is the ovaries, testes, the STEM cells that create eggs and sperm, and the eggs and sperm, but particularly the STEM cells that create eggs and sperm, if it infects those, then it gets passed down to the offspring of that organism. So daughters and sons- Athena (01:05:28): part of your genome- David (01:05:29): That's part of the genome. Dave (01:05:31): Now is that, is that how HIV is passed from parents to kids? Or it's just- David (01:05:33): No, it's not. HIV doesn't do that, but some retroviruses do that. They infect the germline. They infect, um, ovaries and testes and their STEM cells. 8% of the human genome is viral DNA from retroviruses that have infected our germline. Dave (01:05:54): Really! David (01:05:54): 8% of the human genome is viral DNA. It doesn't come down to us through the endless lineage of animals leading to mammals leading to primates leading to humans. It has come in sideways over a period of time, maybe early in the mammals', um, history, um, and it infected the germline and become part of the germline viral DNA. 8% of all of us, including one stretch of DNA that produces that, that is now known as a gene called syncitin 2 S-Y-N-C-Y-T-I-N, and that gene syncytin 2, um, creates a, um, a membrane between the placenta and the fetus that's completely necessary for successful human pregnancy. Dave (01:06:42): Really, without that virus, we couldn't- David (01:06:44): Correct. Athena (01:06:46): Well, I mean, when you guys couldn't, you know, have a successful placenta situation in your body's either, but I could, so. [Athena laughs] Dave (01:06:55): Well we still have this viral- [Athena agrees]. David (01:06:55): We still have it. Yeah, we have it too. Yeah. [agreement] Dave (01:06:58): Interesting. So yeah, that's what I was going to ask. How it affects us. So, so sometimes it's actually beneficial. David (01:07:03): Yes. Yes. Um, now how did, how did mammals ever come into being if they didn't have this membrane between the placenta and the fetus? Somewhere early in the, um, in the evolution of pre-mammals, some individual became infected with a version of this retrovirus, wasn't syncytin 2, it was an earlier version and created a primitive possibility of a membrane that would allow internal pregnancy. Before that it's reptiles and birds, you know, they lay eggs on the ground, but there are disadvantages of laying your eggs on the ground. If a predator comes and you runaway, you can't take your young with you, there're eggs on the ground. If you're having an internal pregnancy, you have a fetus inside you, the predator comes, you run away, the fetus goes with you. Dave (01:07:51): Sure. David (01:07:51): There's an advantage there. Athena (01:07:52): Yeah. Yeah. But, so I learned from David Hage though, and I used to think also that mammals were like, were, you know, internal gestation was invented, but apparently it's like all over the tree of life that there's internal gestation, not just mammals. [David agrees] So, but there's probably some really interesting story there with like what this virus enabled us to do [David agrees] in terms of nutrient transfer or mediating the conflict between the mother and the fetus. So, yeah. So you know, really, really fundamental kinds of abilities that we almost kind of take for granted in our physiology are, are there because of these, this viral DNA that's in our bodies. So- Dave (01:08:33): I'm curious how they know it's 8%. Like how- David (01:08:37): Sequencing the human genome and matching it against retroviruses and saying, where did this piece come from? Well, look, here's, here's a version of it over here. Dave (01:08:45): Okay. So- David (01:08:47): Matching, you know, molecular phylogenetics. Dave (01:08:51): Okay. Athena (01:08:53): Cool. Yeah. So, so in terms of this like, you know, the way that the tree of life is sort of, you know, um, entangled with itself, I mean, even just the, this idea of, um, the origins of the cells that make us as eukaryotes, right that there's a sort of tangled tree story of that as well, right? David (01:09:15): Oh, you mean endosymbiosis? Athena (01:09:17): Exactly. David (01:09:17): Yeah. Okay, yeah. So, um, so, uh, as Athena said, you know, we are, eukaryotes. We belong to one of the three major kingdoms of life. Um, and our particular kingdom of life has complex cells that have cell nucleus and have internal organelles, um, that are like internal organs in our body and the liver, heart, lungs. Dave (01:09:43): So is that- what does eukaryote mean? It means that we have- David (01:09:46): Uh, it means that we, we have complex cells with the nucleus cell nucleus holding our DNA in a nice little package. Dave (01:09:53): Sure. David (01:09:53): But then we also have these internal organelles. One of them is called mitochondria and that's, it's sprinkled like pepper, you know, like pepper flakes through our cells. Dave (01:10:04): Mmhmm, I remember that. David (01:10:04): Yeah. And, and those, um, those little organelles package energy package, ATP molecules that we can use help us engage in more complex processes than a bacterium can. Um, where do the and plants have, they have mitochondria. They also have chloroplasts which helped them create, let's see, how does it work? They take sunlight in they create sugars, right? Dave (01:10:30): Sure, yeah. David (01:10:30): That's what you do in a chloroplast. [Athena and Dave agree] So it's also a form of, you know, harvesting and using, harvesting energy and making it available to the cell. Plants have chloroplasts plants and animals have mitochondria. Where do those come from? Theorists in the late 19th century started suggesting that those were captured bacteria that 2 billion years ago or some time that the first mitochondrion was actually a bacterial particle that another cell swallowed or perhaps became infected by and then either never digested or never recovered from that little visitor came to stay. That little visitor replicated itself. The cell replicated, the visitor, replicated the cell visitor and they, they established a symbiotic relationship. One of them inside the other and the bacterial particle eventually turned into mitochondria. Mitochondria have genomes That's why they talk about mitochondrial Eve, because mitochondria has a genome that's different from your cellular genome. What is that genome similar to? It's similar to the genome in an alpha proteobacterium. Because 2 billion years ago, one cell captured one alpha proteobacterium [Dave laughs] and it came to stay. Likewise with chloroplasts in plants. They sequence, chloroplasts have genomes. What does the genome look like? It looks like the cyanobacteria genome. Um. And that's because sometime 2 billion years ago, this occurred more than one time it occurred, apparently several times. A cell swallowed a cyanobacteria particle and it came to stay and it established a symbiotic relationship and evolved into chloroplasts. Dave (01:12:33): And then whenever that cell reproduces itself, it sort of reproduces both- David (01:12:37): Yes. Yeah. Because the organelles are reproducing themselves continually within the cells. And then when a cell reproduces, um, it, you know, the share of its protoplasm goes both ways. Athena (01:12:50): Do I remember correctly that a bunch of the genes that were sort of mitochondrial genes are now in the nucleus of our eukaryotic cells? [David agrees] So there's sort of been like a bit of a reshuffling of the controls, so to speak. David (01:13:05): Yes, yes, yes. So some of the, the mitochondrial, um, predecessors within us, the ancestors of mitochondria gradually downloaded some of their genes to the nuclear genome. That's where they are now. And the genome of a mitochondria - mitochondrion, the single mitochondrial particle is smaller and simpler than the genome of an alpha proteobacteria as we can see it today. Where are those missing genes? They're in our own genome in the nucleus. Dave (01:13:36): Interesting. Athena (01:13:37): So it's almost like we can't really distinguish the individuals anymore. Right? David (01:13:43): Yeah, yeah. That's one of the things I say at the end of my book, "The Tangled Tree," that all of this work in molecular phylogenetics, including work by Lynn Margulis, who we're describing her idea of endosymbiosis, um, uh, and all this recognition of horizontal gene transfer, it tells us a couple of things. It tells us that three things that we considered sacred categorical truths are not categorical truths. The fact that a species is a species and it doesn't move genes sideways across species boundaries. And we know that's- Athena (01:14:23): Not true. [laughter] David (01:14:25): It's true-ish, but it's not categorically true. [Athena laughs] Um, an individual is one thing. No, we know that we are chimeras and every other kind of complex creatures are chimeras. So an individual is true ish, but it's not a categorical truth. And we used to think that we know, knew that the history of life on earth was shaped like a tree. Wrong. True-ish, but not categorically true because yes, there is a strong tree like signal in the history of life, but that tree is a tangled tree because some of the limbs don't just diverge, they converge, they flow into one another. Dave (01:15:03): Wow. Athena (01:15:04): So we are made of lots of creatures actually. David (01:15:07): Yeah. Yes. Athena (01:15:07): Yeah. Kind of come together. We're like Frankenstein's kind of made from the parts of lots of things and- David (01:15:14): And that doesn't even begin to get into the, uh, microbiome, [Athena agrees] you know, because those, those critters are in us, thousands of different species of bacteria and, and other, you know, single cell microbes. Um, but they're not part of our genome. [Athena agrees] Dave (01:15:30): And they get passed from parent to child? David (01:15:33): Um, to some extent, but to some extent. Yeah. Um, there's a whole ecosystem of, of microbes that could pass from mother to child. Athena (01:15:43): Yeah. But there's a lot of influence of your environment on your microbes too, so David (01:15:48): Right. And there's a lot of evidence, correct me if I'm wrong about this, but it's a lot of evidence showing that if your kids get raised in an environment that's too sterile, um, that will be disadvantageous to them in the long run, that that might lead them to be asthmatic or have other, um, symptomatic conditions, other problems. If they, if they don't acquire a rich enough microbiota early enough, um, it can be problematic. Dave (01:16:17): So let your kids share needles. [laughter] David (01:16:20): Don't let your kids share needles. [laughter]. Athena (01:16:20): Hey, Dave! [Laughter] David (01:16:20): But, so when your one year old, when your one year old drops her, um, what do they call it? Dave (01:16:29): Oh, the lollipop. Or, the- Athena (01:16:30): No. Dave (01:16:30): No the pacifier. David (01:16:32): Pacifier. When your, when your one year old drops her pacifier in the airport, pick it up and stick it back in her mouth. [laughter] Athena (01:16:43): That is not official medical advice. [laughter] David (01:16:46): That's true. Thank you, Athena. Athena (01:16:47): You're welcome. [laughter] So, so let's, let's like big picture a little here. So, I mean, we talked about like all of these different ways that we are made of other forms of life and these intersections between different, you know, forms of life in terms of disease. And I mean, there's so many ways that we're influenced by things that are not us and our, like the whole idea of like this podcast is, you know, what, like how are we influenced by things that are not us? What are, you know, those things. And then are those a problem for, for our autonomy, for how we think of ourselves, for, um, how we want to be going forward in the future. So, so always kind of come to this question at the end of, you know, if we sort of take the things that we've been talking about today, and I don't know, I think maybe the zoonotic diseases is maybe the most zombie apocalyptic kind of topic. Um, so, so, you know, if we take like what we know about how, you know, zoonotic diseases can be transmitted and if we, you know, we, we turn it up a little bit, like say, okay, maybe it's a little easier for, um, you know, diseases to transmit between species or maybe humans are a little more vulnerable. Like, you know, what is the possible zombie apocalypse that results and you know, what would your, what's your zombie apocalypse scenario for us given what you know about zoonotic diseases? David (01:18:22): I'm not, um, as you know, I'm not, uh, very culturally literate on the, the zombie phenomenon. Athena (01:18:30): Well, you can just make up whatever kind of zombie apocalypse you want. David (01:18:35): Well- Athena (01:18:35): You can use your fiction hat now. So- [Athena laughs] David (01:18:36): What I like to think about is, um, uh, the whole concept of, we mentioned these three categoricals that are now challenging. [Athena agrees] I mean, another way of saying that is self, and this is, you know, this is very relevant in your, your other hat, your professional field when you're not being the zombie queen [Athena laughs] and you're working on- Athena (01:18:57): That's part of my profession now. [Athena laughs] David (01:18:59): -cancer. And that is the notion of self versus non-self. [Athena agrees] The integrity are, wondrous, you know, um, innate and adaptive immune systems that are patrolling, you know, to try and sort self from non-self. And then when it comes to cancer, it's a matter of sorting self from self and drawing the line where self becomes non-self, the whole thing. [Athena agrees] Um, of what does it mean to say, this is myself when I say this is myself, I realized that, that, you know, to use Richard Dawkins' phrase, um, you know, I'm a vehicle for genes moving through space, moving through time, moving through, you know, if I have children moving through generations, I don't have children. Athena (01:19:50): You do have dogs though, right? David (01:19:51): I do have dogs. Athena (01:19:51): So they can transmit at least your microbiome. David (01:19:54): That's right. Yep. [Athena and Dave laugh] Yeah. And you know, a person, a person who lives with three big dogs, I'm sure has a different microbiome than a person who doesn't. [Athena agrees] Um, my wife and I live with three big dogs, a cat, and a ball Python. Athena (01:20:13): Wow, that's awesome. David (01:20:14): Some rich mix of possibilities there. Athena (01:20:16): Well, there was a study that showed that, um, people who live in the same house with dogs have more similar microbiomes to each other, the humans do, than people who live in households without dogs. David (01:20:28): Really? Athena (01:20:28): Yeah. And also, you know, they have similar microbiomes to their dogs, but it actually affects the humans. [David agrees] Anyway. Sorry, I interrupted your- David (01:20:37): Yeah so zombie apocalypse, I don't know. I mean I'm helping these, um, these, uh, I don't have any cyanobacteria in me as far as I know, but I certainly have the descendants of alpha, alpha proteobacteria and all my mitochondria. I've got all these other microbions microbiomic, you know, critters living in me. I've got follicle mites in my eyebrows. I've got all kinds of creatures living on my tongue, um, all over my skin. So I'm this, um- Athena (01:21:09): And you're not like unique. All of us do. David (01:21:11): Yes. Yes. [Laughter] Athena (01:21:14): You're not like coming in here crawling, and- [laughter]. David (01:21:20): Right. Right. We all are. Each of us, each of us is, is a, is a gaily, is a Paisley, painted a school bus rolling down the road, filled with creatures of all sorts, carrying them from one phase of their evolutionary history into another. Um, and, um, you know, we're, we have our, our individual sense of ourselves, but it's also to remember, it's good, good to remember how connected we are, how we we're just this sort of Paisley school bus for all kinds of creatures, um, moving along and you know, we live, um, you know, threescore and 10 years or whatever, and then, um, it goes back into the ground [Athena agrees] or it goes into the, um, the, uh, crematorium. Um, and our nutrients come out. And in some cases, if we go into the ground, some of the cells in us, um, continue surviving and replicating and going onward. Athena (01:22:22): So for you, the zombie apocalypse is all of us and our microbes and our zoonotic diseases are on a school bus singing kumbaya. [laughter] David (01:22:34): Uh, I think of it as, I think of it as a Ken Kesey sort of school bus filled with merry pranksters, you know, taking LSD and, and, and playing the Doors. But that's, you know, that's my generation. Athena (01:22:51): So are you worried about zoonotic diseases as someone who has studied them extremely extensively? David (01:22:58): Yes. I'm worried about the number of people they are killing in Eastern Congo right now. Um, I'm worried about, um, uh, the number of, um, kids in sub Saharan Africa are dying of malaria each year. And malaria as I explained in my book is in the long scope of things is a zoonotic disease because everything comes from somewhere. And we're a relatively young species. So all of our infectious diseases have, have come from earlier, you know, animal forms that it carried them. [Athena agrees] Um, am I worried that Ebola is gonna come to the U.S. And and kill off a lot of us? No. And during the 2014 Ebola epidemic in West Africa, I was asked that question on TV more than a few times because I had written about this stuff. [Athena agrees] I said something to um, to um, Anderson Cooper one night on his show that, um, Rush Limbaugh picked up the next day, um, Athena (01:23:59): Which was? David (01:24:00): uh, Anderson Cooper asked me, um, well, so, uh, people have come, some people have come back from Liberia in West Africa having worked there is volunteer medical people. Um, they might be infected with Ebola. One man, the Liberian has come into the U S and then came down with Ebola and died. Um, should we close our borders to Liberia? And this is live on and the Anderson Cooper show. And I'm sitting in a TV studio in a basement in Bozeman, Montana, staring at a, at a camera. Um, and I think first of all, that's not a great question for me and I shouldn't be answering that question. I'm just here to talk about the science side. And the second thing I said was, well, Liberia is a country that exists because of human slavery because of American slavery in the 1840s and 50s. So how dare we turn our back on Liberia? And Anderson Cooper said, okay, fine. And went on to the next panelist and I went home and then 11 o'clock, the next morning, a friend of mine called me. I was sitting in my quiet office and he said, dude, [laughter] do you know that Rush Limbaugh is lighting up his base at your expense at this moment? Because there's some wacko liberal in Bozeman, Montana who said that Americans deserve to get Ebola because of slavery? Athena (01:25:35): Oh my God. David (01:25:37): And so for 24 hours or so, I was Rush Limbaugh's favorite liberal moron. Wow. Uh, I was thinking about getting a pin made up, um, that I could wear proudly that says Rush Limbaugh called me a wacko. [laughter] And then that passed, went away. Athena (01:25:57): So. So why do you think we don't really have to worry in the U.S. About outbreaks? David (01:26:03): Well, because Ebola is not the one that's gonna get us Ebola, um, is transmitted only as far as we know on bodily fluids. Ebola, um, is a terrible disease if you're an impoverished, um, or struggling person in an African village with insufficient medical material, um, to deal with it so it can be isolated and stopped. Um, it's a terrible disease for people in those circumstances. The ones that are more likely to sweep through, um, developed countries and big cities in the U.S. around the world are, are other diseases that are transmitted, um, uh, through the respiratory route, airborne viruses, single stranded RNA, viruses, um, that, um, mutate quickly and can travel on a sneeze. And that's not Ebola. That's, uh, that's flu, that's SARS, that's MERS, and others that we haven't heard about yet. Um, but, and this is not me saying this, this is the experts that I talked to and in the course of researching "Spillover" and I asked them what, what is the next big one look like to you? The one that could spread across now that we're all globalized and you know, and uh, Hong Kong, a bird market in Hong Kong is only 14 hours away from Toronto or New York. And the experts told me single-stranded RNA viruses, and it's a certain, several families of viruses, uh, that have high mutation rates, um, replicate quickly, mutate quickly, and uh, in many cases can be passed by the respiratory route. On a sneeze, on a cough, and also in some cases, um, result in shedding of lots of the virus before people are lying down sick, when they're still walking around going to work sick. They're feeling not very good. They're sneezing, they're coughing, but they say, oh, I can go to work. I'm going to get on the subway, I'll go to work. That's the profile of the viruses that have the capacity to kill millions of people. Athena (01:28:16): So it's the Walking Dead like when people can be up and walking around. David (01:28:21): They're perfect. Athena, nice job bringing it all back around to the Walking Dead. [laughter] It's the zombie apocalypse by way of single stranded RNA virus. Dave (01:28:33): Yeah. So what can we do to, uh, avoid this, uh, you know, is there anything we can do to- Athena (01:28:40): To protect ourselves, and others- David (01:28:42): Tell your congressmen that you disapprove of cuts in the budget of the CDC. Dave (01:28:47): Okay. David (01:28:48): That's a concrete thing because those people are really knowledgeable, really expert, really courageous. Um, the people from the CDC and other organizations like that in other countries who go out and who deal with these, um, potential pandemics when they're still just outbreaks. Athena (01:29:06): Yeah. So the CDC, which is a Center for Disease- David (01:29:09): Center for Disease Control and Prevention. Yeah. Athena (01:29:11): And they're funded by our tax money. Right. To help protect us from these kinds of issues. David (01:29:17): That's right. Yes. Athena (01:29:17): Yeah. Anything else that that you can do, I guess stay home if you're feeling sick. David (01:29:21): Stay home if you're feeling sick, vaccinate your kids. Yes. Vaccinate your kids for their own safety and for the safety of the, of the kids that they go to school with. I don't think you have the right to send your kids to school unvaccinated if they might be carrying a virus that is going because of that is going to be passed to other kids who might also be unvaccinated who maybe didn't have the opportunity to be vaccinated. I know that that's, you know, the herd immunity argument maybe is not the most immediately practical and appealing to people who are concerned with their own kids. So do it for your own kids, but think about other kids, too. Athena (01:30:08): So any other, uh, any other ways that we can protect ourselves or others? You too, Dave, do you have any thoughts? Dave (01:30:16): That's a pretty good list. Athena (01:30:18): Yeah? Wait, what do you think of those masks? I see people wearing around in the, in the airport and stuff like that. Does that- David (01:30:26): well, when I first saw those, I saw some people, like when I left Southern China, having spent time there crawling around in caves, helping a biologist look for the SARS virus in bats. Um, and we weren't wearing protective gear. I asked him, why are we not wearing protective gear? There's an answer to that in my book. But then I got on a plane to fly- Athena (01:30:49): Buy the book! [Athena laughs]. David (01:30:49): -from Southern China back to Hong Kong and I saw a couple, I think they were Japanese tourists and they were wearing masks. And I thought, that's not gonna save you. These little, you know, little entry level, um, um, sort of gauze masks. But, um, I've, I've seen more of those over people in airports over time and I've come to suspect that mostly what they're doing is, um, trying to protect other people from their own germs. If they've got a cold, then maybe, and I think maybe there's, there's, there's an ethic in, in particularly in Japan, it says, if you've got a cold, don't get on an airplane without wearing a mask. Athena (01:31:29): Aah. David (01:31:29): It's your responsibility to other people. So now when I see those things, I say thank you for being so considerate. Athena (01:31:35): That's a good point. Right? So, and they might do a better job of protecting, right? [David agrees] Cause they're going to block a sneeze from aerosolizing all over them. David (01:31:44): Right? Right. Yeah. And if you know, if, if the virus is already out there, aerosol aerosolized in the plane, then wearing one of those things is probably not going to protect you because it can probably also get in through your eyes. But if you're the one who's doing the sneezing, you might be able to protect other people by wearing that mask. Athena (01:32:04): Hmm. Yeah. Well, and I guess, you know, maybe there's a sort of thread running through all of this that you know, we can think about, you know, how do we protect ourselves, but then also for all thinking about how do we protect others if we might be infectious. [David agrees] Then you know, ultimately we'll all be better off. David (01:32:23): That's right. That's part of this is that, yeah. If you want to protect yourself and your kids, you need to worry about everybody else being protected too. [Athena agrees] 'Cause this stuff goes everywhere. Athena (01:32:33): Yeah. Well, thank you so much for sharing your brains with us- David (01:32:37): You're welcome. Athena (01:32:37): For this episode of Zombified. David (01:32:39): You're welcome. This is fun. You guys. You guys rock. You have fun here. I see that. [laughter] Athena (01:32:44): Well we had a lot of fun talking with you. Dave (01:32:45): Yeah. This was really interesting. Outro (01:32:56): [Psychological by Lemi] Athena (01:34:04): Zombified is a production of ASU and the zombie apocalypse medicine Alliance. Thank you to the department of psychology, the interdisciplinary cooperation initiative and the ASU president's office, the Lincoln center for applied ethics and to all the brains that helped make this podcast including Tal Rom, who does our great sound, Neil Smith, who makes our amazing illustrations and Lemi the creator of the song, "Psychological." Thank you also to our entire Z team of ASU undergraduates and graduate students who work tirelessly to transcribe the transcripts for the episodes and um, help with all sorts of other aspects of the podcast. You can follow us on Twitter and Instagram. We are zombified pod and zombified podcast on Facebook. Our website is zombified.org. You can also support us by becoming a patron on Patreon. We are all educational. We have no ads and just $1 a month on Patreon will help us make zombified happen. You can also buy our merchandise. We have awesome stickers and t-shirts available on our website. Athena (01:35:18): At the end of every episode, I share a bit of my brains. And today I just want to offer a little tidbit, which is that I think that what David Quammen talks about in this episode in terms of how the tree of life is so tangled and we are made of all of these different creatures that are kind of sewn together in this amazing biological tapestry that I just love that I love thinking about who we are as organisms. Um, in this new hub, we kind of can be decomposed into all of these different parts, whether it is the bacterial origins of our mitochondria or thinking about how we are literally made of lots of cells that are not genetically from our germline. If you think of the role of the microbiome in all of us humans, you know, there's about half of our cells are microbial and a lot more of our genes are microbial than from our germlines. So I think that we ourselves, each of us is sort of tangled evolutionary tree, and I find that, I guess a little bit more comforting than terrifying. Thank you for listening to Zombified, your source for fresh brains. Outro (01:36:50): [Psychological by Lemi]