April 4, 2026

Space Pathogens In Fiction & Reality

Send us Fan Mail A parasite that senses you coming. An “egg” that waits for the right moment. A life cycle designed to turn a host into a nursery. Space pathogen sci-fi stories hit so hard because they borrow from real evolutionary tricks, and in this episode we put that biology under a microscope as we dissect out some of our sci-fi favorites. We start with the Alien franchise and unpack what makes xenomorph horror feel believable: host detection, parasite-like behavior, and uncomfortable pa...

Send us Fan Mail

A parasite that senses you coming. An “egg” that waits for the right moment. A life cycle designed to turn a host into a nursery. Space pathogen sci-fi stories hit so hard because they borrow from real evolutionary tricks, and in this episode we put that biology under a microscope as we dissect out some of our sci-fi favorites. We start with the Alien franchise and unpack what makes xenomorph horror feel believable: host detection, parasite-like behavior, and uncomfortable parallels on Earth like ticks that track hosts, embryos that respond to temperature stress, and jewel wasps whose reproduction is basically nature’s version of a chestburster scene. From there, we shift to the classic fear that something could arrive from space and infect us, examining the hypothesis of lithopanspermia and the Murchison meteorite as real-world anchors. Then we flip the question: what if we are safe from space, but space isn’t safe from us? What if the most realistic space biosecurity threat is humans bringing microbes with us? We talk astronaut health, microgravity, radiation, circadian disruption, immune changes, microbiome shifts, and how space impacts pathogens. We dig into viral reactivation data, and what that could mean for longer missions and eventual Mars travel. Subscribe, share the episode with a sci-fi fan or a biology nerd, and leave a review so more listeners can find Infectious Science.

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00:09 - One Health And The Big Question\n

00:46 - Space Pathogens In Sci-Fi\n

03:12 - Alien Biology Meets Real Parasitism\n

10:55 - Can Meteorites Bring Life\n

17:28 - Human Health Risks In Space\n

20:35 - Microbes Get Weirder In Microgravity\n

25:03 - Immune Shifts And Viral Reactivation\n

28:49 - Space Ethics Junk And Who Controls Access\n

31:22 - Listener Prompts And How To Engage\n

WEBVTT

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This is a podcast about OneHealt.

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The idea that the health of humans, animals, plants, and the environment that we all share are intrinsically linked.

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Coming to you from a team of scientists, physicians, and veterinarians, this is Infectious Science.

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Where enthusiasm for science is contagious.

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Hey everybody.

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This is Camille, and I am here with Alex.

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Hey, it's great to be here, Camille.

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Thanks for having me as always.

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Yeah.

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And thanks everybody for joining us for this episode of Infectious Science.

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It's going to be a very fun one.

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I'm super excited.

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We've been wanting to do this one for a while.

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So this is really about space pathogens in fiction and reality.

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I am a huge sci-fi fan.

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I don't know about you, Alex.

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Truth be told, sci-fi has never been one of the genres that I've been really big into.

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But in going and preparing for this episode, I've just been taken aback by how much meat there is on the bones in there as far as things to pick apart and how some of these visions of reality come to life sometimes, and be it from things like Alien to the Andromeda strain.

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Yeah, yeah, yeah.

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And I so I'm I'm gonna convince you worth your time.

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And especially what you're describing is my favorite type of sci-fi, right?

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Where like they're taking very real things and then of course setting them in a very fictional setting or kind of over-exaggerating them, but that they're kind of drawing things in that just make it interesting enough to like intrigue me that I'll stop during the book and I'm like, oh, how does this actually work?

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Like when you're like this deep in the ocean, or like, what does this look like in space or that kind of thing?

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And I just feel like what I really love about fiction is that I think it prompts you to think about our own reality in a different way and start to put pieces together that you wouldn't necessarily have done.

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And so, you know, as those who have been longtime listeners of Infectious Science know I'm a big reader.

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I love sci-fi.

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I also read a lot of pathogen horror.

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Unsurprisingly, these two genres have a decent amount of overlap, which is really gonna be highlighted in this episode.

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But there's tons of really popular fictional books that lean into the idea of things like space pathogens.

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There's all kinds of movie franchises, some of which we're gonna talk about today.

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And I also recently came across an article in the Biochemist, which I thought was really interesting that this got published.

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It's actually written by someone who has a PhD, and it was called Science Fiction: The Biology of the Alien in Alien.

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Alien, like capitalized as in the franchise.

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And I thought it was really cool to read because, you know, in it, the authors are suggesting that common themes of sci-fi are really ecological.

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And I think that as scientists, that's something we do have an interest in because sci-fi really focuses on things like competition, on predation, on parasites and pathogens.

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And of course, what's interesting to me as an infectious disease biologist is definitely the infectious disease aspects of science fiction ecology.

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So if that sounds interesting to you, keep listening for some of my favorite sci-fi recommendations and also some thoughts on the importance of speculating on fiction to really better understand our own reality, as well as a discussion of what we actually face in reality.

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Are there any real pathogenic threats from space?

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So we're gonna talk about all of that.

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But first, let's start with the most well-known example of sci-fi pathogen horror.

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Like I feel like it's been around a while, like quintessentially, if you said space pathogens to someone, they would probably think about the alien franchise, right?

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Well, of course.

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Um, yeah.

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It's like super spooky, really fun.

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It also really, I feel like ties in a lot about corporations and what's good and who's out for like humanity's good and that kind of thing.

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So there's all kinds of aspects tied up in this.

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But I think this is cool because the xenomorphs, which are the very creepy-looking aliens featured in it, actually have a whole life cycle, right?

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Like just like something would on Earth, particularly parasites, right?

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And for those that have watched the movies, Alien features eggs that detect when host, which in a franchise is us humans that we're the host, unfortunately, for us in the sci-fi movies.

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These eggs detect when hosts are near.

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And maybe this is just me, maybe this is just a thing I do.

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But when I come across something that I think is really cool in fiction, I'm like, oh, how close to reality is that?

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And uh, what I found was actually really fascinating.

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So I didn't know this, but it's not a super far-fetched notion that eggs can basically detect something in their environment because there's actually real life examples of eggs sensing their environment on Earth, right?

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So like frog eggs are really vulnerable to dehydration.

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So if temperatures spike and temperatures are increasing, in some species, those frog embryos will hatch earlier to escape that lethal warming.

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In the real world, parasites, which are not in their egg stage, like ticks, can also sense in their environment to find blood fields.

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I just thought that was a really interesting thing.

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And I wish Dennis was on with us because I wanted to ask him more about like how ectoparasites like ticks can sense hosts.

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It's so fascinating.

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And I think we're always learning more and more about it.

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No, absolutely, yeah.

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Because I generally know about the role of Howler's organ on ticks in order to go and to like sense radiant heat and can enable detection of like carbon dioxide and things like that, which helps to inform them in terms of questing for blood meals.

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But truth be told, yeah, Dennis is the tick expert here, not me.

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Yeah, yeah.

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A resident tick guy.

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We need him so we can ask all our sci-fi questions.

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But still, it's interesting to think about how how Alien does feature eggs that do have similar sorts of temperature sensing roles that that ticks do, that we see with these frog eggs.

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And so I guess what happens with these eggs once they sense a host, Camille?

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How do we get from the eggs then onwards towards the infamous chest burster scene?

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Well, yeah.

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So you've got to watch Alien.

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Once the you know, the eggs sense a host, the face hugger stage is activated.

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So that's the thing where like the person's face is covered and it's also like a very quintessentially alien, gross scene, similar to the chestburster.

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And I thought this was really interesting because in this same article from the biochemist, they talked about how there's a version of this in the real world.

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There's obviously not face huggers, but in reality, there's actually insect parasitic roundworms that will become really active in caterpillar facidity.

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And that ups the chances of them entering spiracles, which are respiratory openings on the caterpillar and on other insects.

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So, not quite a face hugger, but similar idea that they go right for the face, like for kind of access to the body.

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Um and then, of course, the next stage is the chest burster, as you said.

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So, this is actually pretty similar to how something like a jewel wasp, though, would reproduce on Earth.

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Oh, really?

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Um, yeah, if you've never seen this, go to YouTube and look up how jewel wasps reproduce.

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There's tons of cool like videos from a bunch of different nature organizations.

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So jewel wasp infetamate roaches, drugs them, and then they basically lead them to their burrows and they lay a single egg on them and then they entrap the roaches in the burrow.

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And so these roaches are still drugged, but then they can't get out.

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So once hatched, the larvae burrows into the roach and feeds on the still-living cockroaches' internal organs.

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This kind of really has parallels to alien money.

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And then once all that happens, and of course the cockroach will die, they spin a cocoon, and then eventually an adult jewel ross will emerge from the now dead cockroach like a chest burster.

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Oh my god, that is terrifying.

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I need to watch this, but also the chest bursting scene in alien.

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I still think back on that from time to time.

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My family was flipping through channels, and we came across the scene, and it was like over 10 years ago.

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It still lives with me.

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So the jewel laugh.

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Oh, yeah.

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I don't know if this is going to be good for my sleep afterwards if I see that.

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That's fair.

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That's fair.

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This is why I like read horror, but I rarely watch it because yeah, I'm definitely one of those people that can't sleep afterwards.

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I watched The Last of Us with a really good friend of mine who's also into like passion horse.

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We're like, oh, how close to reality is this?

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And I definitely didn't sleep for two weeks afterwards with like nightmares of clickers and stuff.

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Yeah, this is why I tend to avoid watching horror as a genre.

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But of course, I completely understand because I'm the sort of person who I have somehow over the years developed a tendency to watch plane crash documentaries before I go to bed.

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And oh my gosh.

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I don't know.

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I could never it's become somewhat soothing now that it's a routine, but it definitely kept me up a bit later than I would have wanted at first.

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Wow, I cannot.

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I once was speaking with somebody, I think she was a medical student, and she was like, Yeah, I fall asleep listening to true crime podcasts.

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And I was like, I could never that's not something I I could ever do and still function as a human being.

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I would never sleep again.

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That is one genre that I don't read and I don't watch is true crime.

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Oh no, absolutely.

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No, I have some friends who are the same way.

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Like anxiety is like the default state for most grad students.

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So I'm like, why do that to yourself?

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Yeah, yeah.

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But um, I think it's kind of analogous though, uh, to the way that uh the tick life cycle works.

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So from a so for perhaps from a nymph phase, which I suppose we can analogize the chestburster to, right?

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Um then we end up with the adult xenomorph, right?

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Yeah, that we all know and love.

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Do we?

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Yeah.

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But yeah, no, I think you do give a good point on we never really see, yeah, like the chestburster is that nymph, and we never actually see what happens between that creepy little thing going off into the shadows of a spaceship and then a morph into the adult one that's obviously an apex predator.

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But yeah, you're right.

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I think again, this is something that's got a life cycle, which is interesting.

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And I feel like it's also worth speculating on just to think about the parallels that we do see on Earth and that kind of thing.

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And then I also just before we move on from our alien franchise section, I think for anyone looking for more sci-fi horror that is similar to Alien, I can highly recommend books by S.A.

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Barnes, Ghost Station, which has a really interesting take on a parasite, and her book Cold Eternity, which gives like a really interesting perspective on the line between symbiosis and parasitism, which is something that I feel is still hotly debated in the scientific world, right?

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Like what makes something a symbiote so it's coexisting versus what makes something a parasite where it's taking something from whatever the host is, right?

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I feel like sci-fi, in a way, can give us an interesting lens to explore things like that.

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Questions that are almost tinging more on philosophical in the sciences because we have so many examples of like actual life on earth of people disagreeing of is this a symbiosis?

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Is this parasitism?

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What is this?

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So I think it's one of those interesting topics that is covered, but Alien probably does parasitism best as far as horror goes.

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Yeah, I don't think that there's really much ambiguity as far as that one.

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Yeah, no, I agree.

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To switch tracks from aliens, another trope beyond parasitism in sci-fi is the concept of a pathogen, like essentially being located on something in space, right?

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Maybe it's a meteorite, maybe it's taken up residence on a satellite, and then that thing impacts the earth, and then as the story goes, it causes these rampant infections in people.

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And so this sounds like just sci-fi, right?

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But this is an actual scientific hypothesis that you can move life between things like on meteorites or asteroid fragments or comets.

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So it's called lithopenspermia.

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It's this idea that life can spread by microorganisms that are hitchhiking inside meteorites or on asteroid fragments or comets.

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But I do want to emphasize that this is definitely a hypothesis because we don't have any evidence of it.

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But it is a really interesting thing because we see impacts all the time.

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I remember watching so many meteor showers as a kid.

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We have seen evidence for what it's worth of like amino acids, tryptopha and others being discovered on meteorites that do impact the earth, though, right?

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Yes, and this is an excellent point.

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There's a really interesting example.

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It's called the Merchantson meteorite, and there's actually a couple in this meteorite class.

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So what's interesting about this one though is that it was observed while it was falling and then it was collected.

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So it's known as a carbonaceous chondrite, and that's a type of meteorite.

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It basically means it's full of organic molecules like amino acids and water.

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And what's really fascinating about this one and then other ones like it, which is, in my opinion, really stranger than fiction, right?

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Yeah.

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It's that we have discovered amino acids in them, just like you're saying.

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And amino acids for our listeners, just a quick review, molecules that combine to form proteins, they're commonly referred to as the build-in blocks of life.

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What's wild about carbonaceous chondrite meteorites is that we have discovered um amino acids that we haven't previously found on Earth, which is pretty cool.

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So, at least in the case of the Merkinson meteorite, we've found 70 amino acids, and 19 of those were previously known on Earth.

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What's interesting about that is that we can say, hey, these are occurring in deep space.

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And that might also be how they came to Earth, right?

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And we need amino acids for everything.

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That's how we build proteins, that's how we function.

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And all life on Earth contains amino acids.

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And there was actually a nature article published in 2023, which was making the suggestion that carbonaceous chondroite meteorites have been suggested to be the source of amino acids at the origin of life on Earth, which is really fascinating to think about that that these things are coming in from space.

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Although also really not that far-fetched, right?

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Like things hit each other all the time in space.

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Like all of think about the carbon and stuff that's here.

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It wasn't just here all the time.

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Things collide and hit each other.

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Indeed.

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It also makes me wonder, because you when you were talking a bit about the Merkinson meteorite and the sheer diversity of amino acids that were found compared to what was known on Earth, there is something to be said about it, which is something that would be rather difficult to test, but would make me wonder why it is of those particular 19 amino acids would have been the ones to remain.

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And if that was just a sheer product, like the properties of those amino acids compared to some of these others, or if it was something to do with a relative abundance of those compared to other amino acids that were there?

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Like what would the world look like if the basic building blocks of life that we had were different from what we knew?

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Right.

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Yeah, no, that's such a good question.

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That's fascinating.

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And I think you uh make a great point here.

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There's no way to really know for sure that this is how amino acids were originally introduced to Earth.

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We've got no idea.

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It was a long time ago, very long time ago.

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And it's something that we can speculate about.

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That's how we got them here, but we don't know for sure.

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And I think you also make a good point that meteorite impacts probably created conditions for microbial life to flourish, like in the impact itself.

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There's a couple papers out there, if anyone's interested, to look into that.

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But that could also have played a role in how life developed on Earth, that we were basically getting bombarded with rocks from space.

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Um so it's interesting to think about.

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Yeah, yeah.

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But I don't see the Andromeda strain occurring in real life.

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And andromeda strain, they're like, oh, something contaminated a satellite, a military satellite, I think, and then it like fell to Earth.

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I think it was in Arizona.

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They're always like the impacts in Arizona, right?

00:15:05.759 --> 00:15:08.480
Or no, not Arizona, uh, I think maybe New Mexico.

00:15:08.639 --> 00:15:09.919
I think I'm thinking of New Mexico.

00:15:10.000 --> 00:15:10.960
It's always New Mexico.

00:15:11.200 --> 00:15:12.799
It's always somewhere in the Southwest.

00:15:12.960 --> 00:15:13.919
I know what it's about.

00:15:14.399 --> 00:15:15.039
Yeah, I don't know.

00:15:15.120 --> 00:15:16.240
It's just the desert or something.

00:15:16.320 --> 00:15:16.639
I don't know.

00:15:16.720 --> 00:15:18.399
But that's always where it is in sci-fi, right?

00:15:18.480 --> 00:15:28.240
So maybe it's just that's what they're setting is they're like, oh, I don't know if anyone ever listening has ever been out into the American Southwest Desert, but I have a couple different times, and it is truly an alien landscape to look at.

00:15:28.399 --> 00:15:31.200
It is it just you feel like you're on a different planet entirely.

00:15:31.279 --> 00:15:32.000
It's fascinating.

00:15:32.080 --> 00:15:32.639
It's so cool.

00:15:32.720 --> 00:15:39.360
The rock formations and the plants look so different, and also just like Gila monsters definitely look aliens, such interesting creatures.

00:15:40.639 --> 00:15:44.320
The desert landscape at times it is really otherworldly.

00:15:44.559 --> 00:15:48.960
Like from the American Southwest to the Sahara, I think it was in Morocco, right?

00:15:49.120 --> 00:15:55.759
That it was where George Lucas and Star Wars filmed when they were filming the Tatooine, exactly.

00:15:55.919 --> 00:15:58.080
And uh, there's just something about it, I know.

00:15:58.159 --> 00:16:05.279
Although I'm concerned about what you're saying about the American Southwest and the propensity of meteorite impacts.

00:16:05.360 --> 00:16:20.399
I'm in Nevada, so there may not be an Andromeda strain, but if there's a Reno strain, I yeah, and I you know, I read a book that was sci-fi, and it was like, oh, this meteorite here, and then here's this outbreak, right?

00:16:20.559 --> 00:16:20.720
Sure.

00:16:20.960 --> 00:16:25.039
And me naturally being very skeptical, I was like, space is pretty inhospitable, right?

00:16:25.200 --> 00:16:26.879
It's cold, it's a vacuum.

00:16:27.039 --> 00:16:34.320
But if something does live in space, it likely wouldn't thrive on Earth where there's oxygen, where there's different cycles of light and temperature and things like that.

00:16:34.639 --> 00:16:35.120
Indeed.

00:16:35.360 --> 00:16:38.480
And also, most things falling from space superheat.

00:16:38.559 --> 00:16:46.960
And in my opinion, that's probably gonna sterilize them, which is a good thing because people go out, especially in the deserts, because they're easy to find and pick up meteorites.

00:16:47.200 --> 00:16:47.440
Oh, yeah.

00:16:47.679 --> 00:16:50.799
So it's probably a really good thing, like for our own human curiosity.

00:16:51.279 --> 00:16:56.559
There's no evidence of anything like a pathogen as we know it ever coming to Earth from something falling out of space.

00:16:56.799 --> 00:17:04.880
Are there people who speculate that like you could have organic matter in the upper atmosphere that you don't really know, that could it not be superheated, whatever?

00:17:05.039 --> 00:17:07.200
Yes, but again, we just don't know.

00:17:07.359 --> 00:17:09.920
And so I think that's something to keep in mind.

00:17:10.160 --> 00:17:19.839
But I'm pretty glad that we don't have any pathogens falling from space onto the planet because we aren't prepared for it and random people are picking up meteorites all the time.

00:17:21.039 --> 00:17:27.680
But take us away because I just covered everything sci-fi and how it's an interesting way to observe reality now.

00:17:28.000 --> 00:17:31.599
But we also are bringing things into space, right?

00:17:31.680 --> 00:17:33.359
Because we're sending people into space.

00:17:33.519 --> 00:17:40.559
So honestly, from a biosecurity standpoint, space isn't safe from us, even if we are safe from space, as far as we know.

00:17:40.960 --> 00:17:42.559
So talk to us about that.

00:17:42.960 --> 00:17:44.720
Oh, that's a great way of putting it.

00:17:44.960 --> 00:17:49.359
Humans spending time in space can obviously have significant health impacts for them.

00:17:49.440 --> 00:18:16.079
And so, what we've seen from studies of astronauts who have been on the ISS for six months to a year, along with some studies of some cosmonauts from Mir, was that being in space puts humans under biological stressors, of course, microgravity, constant exposure to radiation, disruptions to the circadian rhythm, confinement and inactivity, and all of these things can lead then to these significant conditions that arise as a result of that time and space.

00:18:16.240 --> 00:18:21.200
Osteoporosis, muscle atrophy, and other health conditions like that are things that can emerge.

00:18:21.359 --> 00:18:31.359
But what we also see is that these have significant impacts on the immune system as well as on bacterial and viral activity and replication.

00:18:31.519 --> 00:18:49.680
And so that can impact the microbiome, and these things can have impacts for health, especially during long-term space travel and potential longer-term space travel, especially if we like I know that there have been efforts to try to eventually get to Mars, right?

00:18:49.759 --> 00:18:52.559
That's going to be a bit of a longer journey than it is to get to the moon.

00:18:52.640 --> 00:18:56.960
And these are things that maybe we're gonna have to bear in mind the further and deeper that we go into space.

00:18:57.359 --> 00:18:57.839
Absolutely.

00:18:58.079 --> 00:19:00.160
There's actually a really good book on this.

00:19:00.240 --> 00:19:00.960
It's nonfiction.

00:19:01.279 --> 00:19:02.799
It's called A City on Mars.

00:19:02.960 --> 00:19:03.839
Can we settle space?

00:19:04.079 --> 00:19:04.799
Should we settle space?

00:19:04.880 --> 00:19:06.160
And have we thought this through?

00:19:06.319 --> 00:19:07.279
It's really interesting.

00:19:07.359 --> 00:19:10.079
I highly recommend it to anyone who's interested in space.

00:19:10.240 --> 00:19:13.759
And it just talks about what are the challenges for humans getting in space.

00:19:13.839 --> 00:19:15.279
And you talked about microgravity.

00:19:15.440 --> 00:19:18.720
A lot of astronauts, when they're coming back, have eye issues, right?

00:19:18.799 --> 00:19:23.839
Because they've been in microgravity and that changes the fluids in our eyes, which are very delicate tissues.

00:19:24.000 --> 00:19:28.400
And so I think that it's something to think about that it affects so much of our health.

00:19:28.559 --> 00:19:32.319
And it's also just like we evolved to live on this planet, right?

00:19:32.400 --> 00:19:34.240
And we don't have a planet B.

00:19:34.319 --> 00:19:39.680
And the idea that you can just go to Mars or go to the moon and settle it there and just whatever, no way.

00:19:40.000 --> 00:19:41.680
Not in the near future, at least.

00:19:41.839 --> 00:19:48.559
Not without a lot of tech advancements, a lot of resources strip mined from Earth to get us into space.

00:19:48.640 --> 00:19:51.039
And that's also gonna damage our planet even more.

00:19:51.119 --> 00:19:53.279
So I think it's just a really interesting book.

00:19:53.359 --> 00:19:57.759
It covers pretty much any fun pop science question you could have about living in space.

00:19:57.839 --> 00:19:59.039
So just want to throw that out there.

00:19:59.119 --> 00:20:00.799
As I highly recommend it as a read.

00:20:01.119 --> 00:20:02.559
I'm gonna have to check that out.

00:20:02.720 --> 00:20:04.079
Thanks for the recommendation.

00:20:04.240 --> 00:20:06.000
And no, you're so right about that.

00:20:06.160 --> 00:20:10.319
I remember reading books like The Martian Chronicles by Bradbury when I was growing up.

00:20:10.559 --> 00:20:11.920
A real classic of sci-fi.

00:20:12.240 --> 00:20:22.960
And it was just something that always strikes me about these books that deal with human colonies on other planets is that yeah, we are evolved for gravity here on Earth.

00:20:23.039 --> 00:20:25.599
And it's something that we take for granted being on Earth, right?

00:20:25.839 --> 00:20:27.119
That's just normal, that's life.

00:20:27.279 --> 00:20:35.599
But indeed, as you mentioned, it has significant impacts on so many aspects of us from our vision to the immune system and beyond.

00:20:35.759 --> 00:20:39.839
And yeah, but it also has significant impacts then for some of these microbes as well.

00:20:40.160 --> 00:20:48.640
Like we see, say, when it comes to clepsella pneumoniae, which is an opportunistic pathogen, it's a causative agent for things like pneumonia and UTI.

00:20:48.880 --> 00:20:55.279
The morphology actually changes a bit in space, which enables a greater capacity for biofilm formation.

00:20:55.440 --> 00:20:58.799
And that's a key virulence factor for clepsella.

00:20:59.039 --> 00:21:04.160
So if you end up with a klepsella infection in space, it may be a bit more severe as a result of that.

00:21:04.240 --> 00:21:04.880
We we don't know.

00:21:05.039 --> 00:21:19.119
Or say, like when we try growing Salmonella and Terica cerevar typemurium under space microgravity conditions, it has an increased growth rate in mice under those conditions and it leads to higher fatality rates at lower inoculas.

00:21:19.359 --> 00:21:20.880
But that I know, right?

00:21:21.039 --> 00:21:22.799
Which is a terrifying prospect.

00:21:22.960 --> 00:21:44.160
But that being said, like the implications of these sorts of microgravity conditions or of space travel on humans and on the microbiome within the humans seems a bit mixed in some ways because we see that there's reduced microbiome diversity, but the implications of some of those specific changes in the microbiome aren't entirely clear.

00:21:44.319 --> 00:21:56.640
So, say we see that there are some anti inflammatory genera of bacteria that are positively associated with increased gut health and that might be negatively associated with inflammatory gut conditions like IBD.

00:21:56.799 --> 00:21:59.759
So this includes stuff like the genus Acromansia and decreases.

00:22:00.079 --> 00:22:01.279
In abundance in space.

00:22:01.440 --> 00:22:13.680
Whereas there are genera that are associated with a release of pro-inflammatory metabolites and that are implicated in inflammatory gut diseases like bacteriorides and lacnospira, these increase in abundance.

00:22:13.920 --> 00:22:23.359
But on the other side, we also see that these are there are some genera that are downregulated in inflammatory gut diseases like Fecalobacterium and Rosberia that also increase in abundance during space flight.

00:22:23.440 --> 00:22:31.039
And so it's just the composition changes, and there may be some potential gut health implications on it, but we're not really sure.

00:22:31.279 --> 00:22:39.039
People haven't been in space in some ways for long enough to really measure some of these changes out or the implications of them in great detail.

00:22:39.279 --> 00:22:43.359
And it's such a unique environment compared to life on Earth, right?

00:22:43.440 --> 00:22:51.119
Because we're exposed to so many environmental microbes here, and this ISS and these environments in space are so intentionally sterile.

00:22:51.200 --> 00:23:04.880
And so even the environmental microbiome is completely different because it's dominated, for instance, by human skin flora and things like that, which is not what you might normally encounter when you're just going out for a walk in the woods.

00:23:06.640 --> 00:23:06.880
Yeah.

00:23:07.200 --> 00:23:12.559
I think this is a great point that there's so much we just don't know about how space is going to impact us.

00:23:12.720 --> 00:23:15.119
And also, we've touched on this before in other episodes.

00:23:15.279 --> 00:23:17.279
Humans are these super organisms, right?

00:23:17.440 --> 00:23:19.519
We are, we are not sterile creatures.

00:23:19.680 --> 00:23:26.720
We would not live if we were sterile and didn't have bacteria and viruses and fungi like living on us and in us.

00:23:26.880 --> 00:23:28.720
And that really shapes our health.

00:23:28.799 --> 00:23:30.240
And we co-evolved with these things.

00:23:30.319 --> 00:23:32.319
We co-evolved with gravity the way it is on Earth.

00:23:32.400 --> 00:23:35.759
We co-evolved with viruses and bacteria and fungi that are here.

00:23:35.920 --> 00:23:38.880
And those all shape our health in really important ways.

00:23:39.039 --> 00:23:44.240
And so I think there's just a lot of things we don't know about being in space and how that would affect people long term.

00:23:44.319 --> 00:23:48.079
It's certainly not enough to say, come live on planet B or something like that.

00:23:48.400 --> 00:23:50.720
Because this is the planet that we evolved for, right?

00:23:50.799 --> 00:23:52.240
And so it's always going to be the best.

00:23:52.400 --> 00:23:54.640
And I think that's something to keep in mind.

00:23:54.799 --> 00:24:02.160
But that's really wild too, that the pathogens that we might carry with us, because even as healthy as you are, so many things are totally fine on your skin, right?

00:24:02.319 --> 00:24:05.119
Staff's fine on your skin until you get it into an open wound.

00:24:05.279 --> 00:24:07.920
And we can't just say, oh, this is pathogenic or this isn't.

00:24:08.079 --> 00:24:11.359
But yeah, we're bringing these things into space with us, and then we don't know what happens.

00:24:11.680 --> 00:24:12.160
Absolutely.

00:24:12.559 --> 00:24:16.720
I think it's one of those things where there's certainly so many ethical quanders with it too.

00:24:16.799 --> 00:24:18.240
But I think that's all of space, right?

00:24:18.400 --> 00:24:19.920
This idea that we can bring people there.

00:24:20.079 --> 00:24:23.119
Who gets to go, who's healthy enough to go, that's also a thing.

00:24:23.440 --> 00:24:27.839
Like it's very stringent to get up into space and they still can have medical issues.

00:24:28.160 --> 00:24:30.079
They just had a medical evacuate, right?

00:24:30.160 --> 00:24:31.839
From was that the ISS?

00:24:32.160 --> 00:24:32.319
Yeah.

00:24:32.799 --> 00:24:34.240
I think it was the ISS, yes.

00:24:34.400 --> 00:24:42.799
And I think that it's interesting, certainly, to see how space does go about, in some cases, leading to some of these health issues as well.

00:24:42.960 --> 00:24:56.240
I mean, we see that there's a a propensity of folks who are on the ISS for extended periods of time to develop rashes and things like that, which seems to be related to delayed type hypersensitivity reactions.

00:24:56.400 --> 00:25:03.119
And we know that these environmental stressors can also then lead to shifts then in the immune system.

00:25:03.200 --> 00:25:07.119
So white blood cell counts tend to go up, T cell function tends to be impaired.

00:25:07.359 --> 00:25:15.279
So, say when stimulated with antigens like LPS, say IL8s elevated, which would be indicative of a more pro-inflammatory response.

00:25:15.440 --> 00:25:29.599
Whereas just like nonspecific mitogen stimulation leads to a reduction in production of various cytokines, ranging from like interferon gamma and IL-10 to IL-5, TNF alpha, and these things have pretty varied properties.

00:25:29.759 --> 00:25:34.319
And so the implications of that decrease aren't exactly clear.

00:25:34.400 --> 00:25:39.839
But what we do see is that there is increased viral activity then in space.

00:25:40.000 --> 00:25:49.599
So, say there was a study that showed that up to 61% of crew members on the ISS missions have had uh herpes reactivations of things like Epstein Bar viral or as well as Auster.

00:25:49.759 --> 00:25:58.960
And so that would seem to suggest that the immune microenvironment that is altered by space may be leading to these herpes reactivations, but who knows?

00:25:59.359 --> 00:26:01.440
And that could be a stress response too, right?

00:26:01.519 --> 00:26:03.359
With herpes, a stress response.

00:26:05.920 --> 00:26:09.519
So for those who are not familiar, that's what we commonly call mono.

00:26:09.920 --> 00:26:13.200
So Epstein Barr is the cause deviation of what we commonly call mono.

00:26:13.519 --> 00:26:14.720
So that's really interesting.

00:26:14.960 --> 00:26:25.680
If you see these reactivations, even if people were healthy going up there, you could potentially have issues with viruses that also, I know at least Epstein Bar is associated with the activation of oncogenes, right?

00:26:25.839 --> 00:26:26.559
So cancer genes.

00:26:26.640 --> 00:26:30.079
So that's something to keep in mind that we don't know these long-term impacts.

00:26:30.160 --> 00:26:35.599
And again, we are still trying to understand immunity and development on Earth, not on such life.

00:26:35.920 --> 00:26:41.440
Taking it into an environment that we've created that has very different conditions than the ones we're used to living in.

00:26:41.759 --> 00:26:42.240
100%.

00:26:42.640 --> 00:26:42.960
Yeah.

00:26:43.119 --> 00:26:44.400
It's fascinating to think of.

00:26:44.480 --> 00:26:56.480
And you're quite right about it being potentially a stress response, absolutely, as well, because I can only imagine what it would be like being in space, having your circadian rhythm constantly disrupted, not being able to really go outside.

00:26:56.720 --> 00:27:03.279
I don't know about you, Camille, but I was going stir crazy during the pandemic when I was not able to really go out as much.

00:27:03.359 --> 00:27:04.559
I know a lot of people did.

00:27:04.640 --> 00:27:13.440
And so the idea of just being stuck in a space like the ISS for months, potentially in the future, spaces like that for years at a time.

00:27:13.839 --> 00:27:15.680
Yeah, no, an astronaut, I am not.

00:27:15.839 --> 00:27:21.039
The idea of confinement like that definitely gives me the heebie jeebies more than something like Alien ever could.

00:27:21.200 --> 00:27:28.240
Also, I know this probably just sounds like a a kind of a weird gripe, but humans did evolve to interact with nature.

00:27:28.480 --> 00:27:40.240
And the idea of just being in a tube or a box or whatever we want to call it for a very long time likely has impacts on us that we don't really understand yet because it's just something we didn't evolve to live in.

00:27:41.119 --> 00:27:48.160
So just something to throw out there and keep in mind that again, something like a stress response can reactivate a viral infection like herpes.

00:27:48.319 --> 00:27:50.480
And that has health impacts, right?

00:27:50.799 --> 00:27:51.200
Yeah.

00:27:51.519 --> 00:28:02.559
It's clear then in the long term that space travel may very well have significant impacts on human health that would require further monitoring and potential interventions for longer-term space travel.

00:28:02.640 --> 00:28:11.279
But at least for now, I think that there's so many unanswered questions than ones that we really know at this point, but there's just there's so much fun work to be done.

00:28:11.519 --> 00:28:18.559
I think though, while we may be raising those questions, Camille, I don't think either of us are going to be out in space answering them many times.

00:28:26.480 --> 00:28:32.480
I love having as much oxygen and long showers of water, also just weather and varied food.

00:28:32.640 --> 00:28:35.759
Yeah, I'm definitely a mature astronaut, really, that's for sure.

00:28:36.000 --> 00:28:37.440
They're really interesting questions.

00:28:37.599 --> 00:28:49.519
And I think there's so much we can learn from the space pathogens of fiction and then also the actual reality of what happens when humans go to space and also humans spring trash and other stuff in space and stuff like that.

00:28:49.680 --> 00:28:51.759
That we don't know all the effects of that.

00:28:51.839 --> 00:29:02.319
And that's not something that I think is maybe considered as much as it should be, that we should be mindful of what we might be colonizing other places with, as you mentioned, some of these bacteria and things like that.

00:29:02.559 --> 00:29:06.160
Yeah, no, I I think that's a really interesting, interesting discussion.

00:29:06.319 --> 00:29:07.200
So thanks for that.

00:29:07.599 --> 00:29:20.880
We don't really know, yeah, about these long-term impacts of some of these ways that beyond even the natural and the microbial paths, that we are impacting space when it comes to space junk and things like that.

00:29:21.200 --> 00:29:29.759
And so uh there's so many old satellites and things like that that are just floating around out there that we put up their issues when it comes to that.

00:29:29.920 --> 00:29:44.160
So I think that it'll be interesting to see what further international efforts look like towards collaborating in space and dealing with some of these issues might look like in the long run, along with further space exploration.

00:29:44.319 --> 00:29:45.440
But yeah, I don't know.

00:29:45.680 --> 00:29:56.240
Personally, I will say the one thing that I am hoping for with space in the in the long run, though, is while I don't think I'd ever want to live in space, I do think that it could be fun to visit space at least once.

00:29:56.400 --> 00:29:58.640
But Jeff Bezos, if you're listening, yeah.

00:29:58.799 --> 00:30:00.960
Uh uh makes it more affordable.

00:30:01.920 --> 00:30:04.240
You should get one on one of those like microgravity flights.

00:30:04.319 --> 00:30:05.599
I know someone who's been on one of those.

00:30:05.759 --> 00:30:08.319
She used to work as a Sidecom communicator for NASA.

00:30:08.640 --> 00:30:08.880
Yeah.

00:30:09.039 --> 00:30:13.200
So you you should yeah, I know those exist that essentially civilians can get on.

00:30:13.279 --> 00:30:14.880
So maybe that's your ticket there.

00:30:15.119 --> 00:30:17.200
Personally, I've got no desire.

00:30:19.440 --> 00:30:26.640
But I don't think it's a great idea either to just let you know some large corporation or something control your access to food and water and like healthcare and all that jazz.

00:30:26.720 --> 00:30:28.319
But that's me, so I digress.

00:30:28.960 --> 00:30:30.240
I don't disagree with that.

00:30:30.400 --> 00:30:49.519
And in some ways, reminds me in terms of just like the absolute control that some of these companies have over everything from transportation to food to living conditions to almost companies like the British East India Company or things like that, these conglomerates that had so much influence and power over such massive domains.

00:30:49.680 --> 00:30:57.759
And and hopefully the lesson out of that was that it was ultimately governmental intervention that you know that needed to happen in order to step in.

00:30:57.839 --> 00:30:59.440
We'll see if that happens in space.

00:30:59.599 --> 00:31:01.359
But I know I completely agree with you.

00:31:01.440 --> 00:31:06.720
Although I'm sad to hear, Camille, that we aren't going to be recording an episode of infectious science from space.

00:31:06.960 --> 00:31:07.279
I know.

00:31:07.359 --> 00:31:10.240
I listen, if you want to be the guest from space, go for it.

00:31:11.119 --> 00:31:12.400
Sit firmly on the ground.

00:31:12.559 --> 00:31:17.759
I have to talk myself up to get into an airplane, much less something that's gonna take me into above the atmosphere.

00:31:17.920 --> 00:31:19.039
No, thank you.

00:31:20.079 --> 00:31:22.000
Not for me, not for me.

00:31:22.240 --> 00:31:26.559