SciShow Tangents - SciShow Tangents Classics - Allergies

Episode Date: July 13, 2021

It feels like this allergy season is never gonna end, so we decided to dig into the archives to learn a little more about the pollen, dander, and other tiny things currently making our lives a living heck! Achoo!Head to the link below to find out how you can help support SciShow Tangents, and see all the cool perks you’ll get in return, like bonus episodes and a monthly newsletter! https://www.patreon.com/SciShowTangentsA big thank you to Patreon subscriber Eclectic Bunny for helping to make the show possible!Follow us on Twitter @SciShowTangents, where we’ll tweet out topics for upcoming episodes and you can ask the science couch questions! While you're at it, check out the Tangents crew on Twitter: Ceri: @ceriley Sam: @slamschultz Hank: @hankgreen

Hello friends! Do itchy, watery eyes got you down? Has your nose been running since like April? Ours too. So we're taking this week off to tend to our allergies, and in the meantime, you can listen to this classic episode about allergies to learn more about the microscopic thingies that are ruining your summer. See you next week! Hello and welcome to SciShow Tangents, the lightly competitive knowledge showcase starring some of the geniuses that make the YouTube series SciShow happen. This week, as always, I am joined by Stefan Chen. What's your tagline? Brontosaurus bones. Sam Schultz is here with us as well.

Hello. Sam, what's your tagline? It was a dark and stormy night. Right now, it is a bright and stormy day here in Missoula, Montana, but it may soon transition into a dark and stormy night. Sari is here as well. Hello, Sari. Riley, what's the next nonfiction book I should read? I don't read a lot of nonfiction. transition into a dark and stormy night. Sari is here as well. Hello, Sari Riley.

What's the next nonfiction book I should read? I don't read a lot of nonfiction, so you've asked the wrong person. The Internet Doesn't Want to Be Free. That's one that I read recently. I've heard about that. You might have already read it because you're an internet thinky person.

I haven't read it yet. Then yes, that one. And Sari, what's your tagline? Old spaghetti legs. And I'm Hank Green. My tagline is Old spaghetti legs. And I'm Hank Green. My tagline is strong and mad. Wow.

Every week here on Size Your Tangents, we get together to try to one-up a maze and delight each other with science facts. We're playing for glory, but we're also keeping score and awarding sandbox from week to week. We do everything we can to stay on topic, but judging by previous conversations, we won't be great at that. So if the rest of the team deems your tangent unworthy, we will force you to give up one of

your sandbox. So tangent with care. Now, as always, we introduce this week's topic with the traditional science poem this week from Stefan. What a nice day. I couldn't help but think it's the first blue sky I've seen in 26 weeks. Off to the park where I'm surrounded by things like flowers and birdsong. Oh boy, it's spring. But wait, do I detect a slight tickle in the air? And are those furry pets that I spy over there? Ah, I've been surrounded by pollen and hair. Sound the alarm. It's an inflammatory nightmare. There's no relief in sight. I have no antihistamines. Excited for my walk, I didn't think about these things.

But all I want to do now is find the nearest latrine or some place I can give my sinuses a good ring. What? When they told me I was one of the sensitive few, I thought they meant emotionally. Who knew? My immune system also reacts

in ways that are undue. And so, as a symptom, I'm overcome with achoo. Oh. Our topic for the day is allergies. I guess I'm going to ask Sari what allergies are, knowing full well that it is not simple. Yep. I feel like allergies are categorized as relatively extreme

reactions or abnormal reactions to otherwise harmless things or things that we deem like pollen or hair that are annoying but shouldn't cause your immune system to go into overdrive to defend against them stefan listed some of them like pollen or hair, but they can also be compounds in saliva or proteins in certain foods like milk or eggs. Yeah, gluten. Yeah. And your immune system views that allergen, that protein as an invader, like a bacteria or a virus and launches an immune response.

Is there a common chemistry or biology reason why the body decides that these things are bad? So there are some proteins that are similarly shaped as others. So if you are allergic to grasses, then you might be allergic to eating stone fruits, I think, because the proteins are structured similarly. But biochemically, there is a pretty common thread throughout all allergies in that your immune system, this is where my immunology knowledge gets a little shaky, it has to do with immunoglobulin E, which is an antibody that's responsible for most allergic reactions. And so it is an antibody that doesn't get deployed for a bacterial infection, a viral infection, anything like that, but specifically gets deployed for allergic reactions and I think sometimes

parasites. The way your immune system works is you get exposed to something like a bacteria or a virus, your body recognizes it as bad, and then it uses antibodies and a whole system to sort of like flag it as bad so that when your body encounters it again, you can fight it off. That's like the whole premise of vaccines is that you can protect yourself by introducing either a small quantity or a dead quantity of an agent, infectious agent, so that your body's like, I know you, and then can clamp it down later. What immunoglobulin E is, is like a similar process where it recognizes an agent like pollen as an allergen, but then the next time you see it in your body, your immune system just goes haywire. So it's like, I i recognize you pollen or wasp venom or whatever and then you get a runny nose and and your throat closes up and things

like that so allergies are worse generally with multiple exposures asterisk but they can go away over time as you grow up because who knows yeah also maybe with very small exposures it can actually decrease your chances of getting an allergy but like it has to be it's at specific moments in your life it's very like it it sucks it sucks and like one of the things that we used to think was that like peanuts like might be really dangerous so don't give kids peanuts when they're young but then it was like all these kids are now allergic to peanuts and in part because they weren't exposed to peanuts when they were younger and this is like oh come on so now now the doctor is like i when we had oran they were like you should give him peanuts at this age because maybe it will help him not be allergic to peanuts. And Sari, do you know where the word allergy comes from?

I bet this one's interesting. Yeah, it's weird. And it's very recent. It only goes back to 1906. And it's an Austrian pediatrician named Clemens von Perquette. And he noticed that some patients who were vaccinated for smallpox, using some sort of serum derived from horses, reacted more severely to a second dose. And so he was like, there's some sort of sickness going on. Maybe it's the

immune system and coined it from the terms ergon, which means activity or work in Greek, and alos, which means other, different, or strange. So it's like the immune system's being weird right now. Let's call it an allergy. A strange work. Yeah. It's doing some odd work here. So. And now it is time for Truth or Failure.

One of our panelists has prepared three science facts for our education and enjoyment, but only one of those facts is real. The others of us have to figure out, either by deduction or wild guess, which is the true fact. And if we do, we get a Sam Buck. If we're tricked, then Sam gets the Sam Buck. You can play at home by going to twitter.com slash scishowtangents. Make sure you vote

before you hear the real answer. Sam, what are the facts? It is fairly well known that the bite of some ticks can cause people to become allergic to red meat. And that happens when a tick has recently fed on a non-human mammal. This is what I think from my reading is what happens, but you can correct me if I'm wrong. They feed on a non-human mammal, and then they bite a human, and it releases a compound called alpha-gal into the bloodstream. Alpha-gal is found in most mammals'

blood, but not in apes, so the human immune system attacks it, which can cause a permanent allergy to the compound, so whenever you eat red meat, you have an allergic reaction. But, there is at least one other allergy you can catch via an animal. Which one of these is it? Number one, people living in a rodent-infested house can develop an allergy to hot dogs due to a relatively large proportion of rodent parts in each wiener. Number two. Children are a type of animal, if you think about it, and parents who clean their children's pacifiers by putting them in their own mouths

have been known to develop an allergic reaction to their own children's snot and saliva. Or three. have been known to develop an allergic reaction to their own children's snot and saliva. Or, three, people who spend a lot of quality time with their cats can develop a severe pork allergy due to similar compounds excreted by both gross animals. Sam, you've got to explain to me why you just called a cat a gross animal while I'm looking at an adorable cat right behind you on your beanbag chair. Because she poops in your house, just in a box. I poop in my house too, Sam! Yeah, but you poop in water, and you flush it down the toilet,

and she poops in a box, and it just sits there. They're disgusting. So, okay, before we get any deeper, let's talk about what we've got here. We've got three facts. One, rodent exposure can lead you to hot dog allergies. And we'll talk a little bit more about why that is in a second. Parents cleaning pacifiers with their mouths can become allergic to their kids' spit and snot. Or three, cat exposure can lead to pork allergies because of what was it because of

because they both just are kind of the same inside or something it doesn't have anything to do with the poop in the box in the dust though or does it i don't know does it okay all right i see yeah good play your hand so let's let's move back to rodent exposure, though. So the reason for rodent exposure making you allergic to hot dogs is because there's a relatively high percentage of rodent parts in hot dogs. High percentage? Relatively high percentage. What does relatively high mean?

Compared to other foods. You got a few more rats down there. Okay, thinking like 51% of my sausage is rat. I don't think that would be like a legal amount. Yeah. No, more than in like a steak. Yeah. That makes sense.

Because like you have those big probably industrial meat grinders and rats are scurrying around inevitably and one falls in. You got the rat in your hot dog. It's too bad. It's too bad. It's too bad, really. And then we've got parents cleaning pacifiers with their mouths and they can become allergic to their own kid's spitty snot. Did you put Oren's pacifier in your mouth ever?

No, but I did have him give me big wet kisses. Why would you put a pacifier in your mouth? I don't know. You're the only parent here. Why would you why would you put a pacifier in your mouth you're the only parent here why would you yeah you're like this pacifier is dirty i know what to do well i can see if you like drop it on the ground you think i should clean this off with my mouth because i can protect my own body but my child child needs, I don't know. A sink exists. A sink exists so nearby. Also, I must be a bad parent because my thought is, this child is growing. He's got so much going for him.

I'm sure he'll be fine. I am in decline. I have all kinds of problems. I can't expose myself to these things. I just don't have enough information about the pig and cat one, but I also feel like Sam is being cagey about it,

so I'm not going to squeeze anything else out about it. I'm going to guess pig and cat because I want to learn more about it. I'm going to go with

the parents allergic to children's saliva. I am also going to go with parents allergic to children's saliva. am also going to go with parents allergic to children's saliva the other two seem very far-fetched to me all right cast your vote on twitter now pause cast your vote on twitter now everybody size your tangents at twitter yeah just go to twitter type in tangents that's how i get to it so all right are you back here's the real answer the pork cat syndrome is a real thing

what incredible it's a fairly rare allergy that develops in people that live in households with a ton of cats and they develop an allergic reaction to the blood albumin that cats have i don't really know how do you get this this is why i thought it was far-fetched because how do you get cat blood in you and well, I mean, people love their cats. Come on. I couldn't figure out, and maybe you guys can answer this, because it seems like the allergy that you develop an allergy to the albumin, and then that has a bad reaction to albumin in pork products.

So does that mean that they're really similar, or that they're really different and something weird happens? They're similar. Okay. So you eat the pork, you get a bellyache. I guess guess if you ate your cat you would also get a bellyache too this seems so far-fetched because i just just like it's meat i never get cat meat in me no and it's not it's not other it's not like beef or red meat and maybe cats are white meat i don't know but it's it's just pork and it's mostly just in europe but six american cases

are reported in 2011 and those were the first american cases ever and if you stop hanging out with cats it goes away eventually in most people oh but why would you who needs pork yeah that's true so then the people living in rodent infested home hot dog one people like to say that hot dogs are full of like lots of stuff, but I was reading articles about it, about how gross they really were and a lot of them were just like, oh, they have pig intestines and pig snouts in them. Which, I don't really care. That seems

like an acceptable thing to have in your hot dog. Yeah. It's always like this contains other muscles besides the ones we usually eat. And I'm like, well, good! That's good! I'm glad, well, good. That's good. I'm glad someone's eating those. Yeah, get a little variety in your diet.

So the hot dogs containing mystery meat thing seemed to me to be a little overblown. I couldn't find too much about it. But there are people who are allergic to hot dogs, not because of mice, but because of annatto seed, which is a natural dye that makes hot dogs hot dog color. And it also makes also what color are hot dogs they're like pinky kind of pinky orangey it's also in like doritos and cheetos and like

any yellow food you can think of is pretty likely to have this seed and it can cause some people to develop like ibs and other kind of gut problems yes che, Cheetos, I always think of them as being hot dog colored. They got the same crunch, which I like. What? Check your hot dog expiration date. And then I don't, I mean, maybe you can become allergic to your kid, but what the child allergy one was based on was a study of 184 babies who had parents that regularly sucked

on their baby's pacifier to clean it off which apparently is a thing some people do 65 of those babies like two years later had were much less likely to experience many common food and airborne allergies that are found in children oh and the study concluded that the parents microbiome might give the baby's immune system like a workout, basically. Big wet kisses, good. Big wet kisses are helping him. Helping your boy. Usually when Oren gives me the wettest kiss, it's because his nose is running.

And I will be sick within six hours. Next up, we're going to take a short break. Then time for the fact off. Welcome back. Sam Buck totals. Stefan's got one for his poem. I've got a zero. Sam came in with a hot twoals. Stefan's got one for his poem. I've got a zero. Sam came in with a hot two, and Sari's got one.

Ew. Don't say Sam came in with a hot two. It's too late now. Everybody get ready for the fact-off. Two panelists have brought science facts to present to the others in an attempt to blow their minds. The presentees each have a sandbuck to award to the fact that they like the most. But if they hate all of the facts, they can throw their sandbuck away. And we're going to decide who goes first with a trivia question that I do not have because I am one of the people.

The trivia question is, according to a 2001 study, what percentage of peanut allergy cases are outgrown in people aged 4 to 20? 54%. Oh. I'm going to guess 36. Feels like low to me. I feel like we hear about peanut allergies a lot. Yeah. It feels like low to me.

I was going for the non-intuitive answer. I was like, this is going to be surprising. Well, it was 22%, so you both overshot. That's not surprising. But Sari was closer. Okay. Well, I'm going to go first just to get it over with. So across the globe in cities like Melbourne, Australia, London, England, Naples, Italy, and Atlanta in the US, tens or hundreds or even thousands of people have had their breath taken away literally with asthma attacks because of thunderstorms. And in some of those situations, between 20 and 40 percent of those people had never experienced asthma symptoms before.

So this posed quite a mystery to health professionals. They call this phenomenon thunderstorm asthma, and it's actually pretty rare. So like every thunderstorm doesn't lead to thunderstorm asthma. Scientists' best guess is that it relies on a perfect storm of factors. First, there have to be pollen grains floating around. So it needs to be in like a spring or summer-ish situation where plants are already releasing pollen. And the situation gets dicier if it's pollen from something like ryegrass, but a lot of grasses especially, which are more common allergies. And normally, even if allergens like pollen are blowing around, our bodies have ways to filter out big grains in nasal passages or somehow like mucusy before they

get to our lungs. So after all this pollen is in the air, a updraft of warm air that forms the thunderstorm also sucks up pollen, which get wet and undergo a process called osmotic shock, where the pollen grains explode into smaller pieces like starch granules and germinating fungal spores or other molecular-sized particles that can induce asthma, like the proteins actually trigger it, and can get deeper into our lungs more easily because they can just fly inside our system. And then the downdrafts or outflow in the windy, rainy thunderstorm can carry these particles back down to humans who are breathing in air. And this, in some cases, causes large swaths of people, some of whom haven't dealt with asthma before, to start constricting

their airways and coughing. It seems like this is a bigger problem because when it happens, hospitals are just overwhelmed with asthma cases where a bunch of people who don't have inhalers or aren't prepared for this situation are all of a sudden put into an asthmatic episode. So we'd like to be able to predict when thunderstorm asthma is going to happen so we don't overwhelm our medical systems as much. And because with changing climates, thunderstorms are predicted to become more severe. And so with more severe thunderstorms

and more frequent thunderstorms, it's possible that these factors may combine and cause more thunderstorm asthma. The particle of pollen gets exploded by a pressure differential? I think so. of pollen gets exploded by pressure differential? I think so. Something to do with a pressure differential on water. I couldn't fully understand what osmotic shock exactly does,

but it's something like the warm, wet air swooping it up. It like absorbs the water and then that's too much. And so it bursts, I think, sort of like a cell that would lyse. So in the places that you mentioned at the beginning are those have these happen a lot or is that are those just like certain instances of it happening certain instances of it happening it seems like it's more well reported in europe and australia but it occurs in more places than that. But I feel like the biggest one recently was in 2016 or 2017 in Melbourne. That was when a couple thousand people, like I think 8,000 people, all got asthma at the same time after a thunderstorm.

Well, now I'm paranoid about the thunderstorm brewing outside right now. You'll probably be fine. People who stayed indoors and kept their windows closed didn't breathe in the pollen chunks so okay i'm always inside with my windows closed so all right so is it time for my fact allergies are a problem sometimes your body is like i have identified a bad thing and i'm gonna help you get rid of it and sometimes your body is like i have identified it like a an innocuous piece of plant and now I will make your face secrete mucus for a month. And so that shouldn't happen.

It is a kind of disease or disorder, and we have systems in our bodies that prevent it from happening. One of those systems is a special kind of cell that is inside of your skin called a Langerhans cell. And their job is to present bits of potential pathogens to other immune cells to help them decide how to respond to those potential pathogens. And as part of that, those cells play a role in training our immune system to not respond to things they shouldn't react to. So allergens would be these proteins that we shouldn't respond to, but we sometimes do. Oral Langerhans cells, which are a special kind of Langerhans cells that are in the mouth,

they're also called OLCs, seem to play a really important role in suppressing allergic reactions, and that makes them potentially very interesting for immunotherapy treatments that desensitize a patient to allergens so that we do not have hay fever and stuff. So these OLCs are found in a particularly high density in the vestibular region of the mouth, which is the area between your teeth and the inside of your cheeks. It's like right there. I know this is a podcast, but you can hear where I'm touching, right? So a group of doctors were then like, I have a thought. What if we targeted those cells specifically by creating a paste of some kind that people would rub on their gums twice a day? And then presumably they were like, oh, actually, we already rub a paste on our gums twice a day.

we already rub a paste on our gums twice a day. And so they mixed some immunotherapy serum with regular toothpaste that they bought at the store and they have created a thing. It's called Allerdent and doctors can prescribe it to you. So there are other immunotherapies out there that work similarly. There are ones that work different,

like a kind of vaccine that actually gets poked into you. There are also serum drops that are basically the same thing that you like put onto your tongue and then you have to spit it out. But those are like extra steps, like things you have to do, and they're not particularly pleasant. And so patients don't as often stick with the program for the long term that's kind of necessary to get your body desensitized to the allergens. So patients, unsurprisingly, really stick with the regimen of Allerdent because, like, you got to brush your teeth twice a day anyway. And that makes me wish that, like, every drug could be delivered this way. Like, why do people have to take birth control when they could just brush their teeth? The initial study they did was really small, and it basically just, like, tested out whether it's effectively the same as the serum

drops approach, which is a thing that they'd already tested to see if it was safe and effective, and it was. So basically, they did this tiny study with 24 people to, like, say, like, this is basically the same as this other thing that we already know works and so we're pretty sure that it works but it is a small study so like while you can prescribe it doctors aren't doing it a lot yet but in 10 years from now i make a prediction i will be shocked if you can't buy like allergy decreasing toothpaste at the pharmacy does everyone here brush actually brush twice a day because i'm a once a day i don't know when to fit the other one in wait when right before bed that's the one that i do you don't brush your teeth when you wake up and before you go to work in the morning

no oh i just brushed before i went to sleep oh my god the inside of my mouth tastes like a hot dog filled with rat every time i wake up no this is i don't know your breath doesn't even stink that's what i'm saying i'm good to go maybe you just don't need to brush your teeth it's like when you stop washing your hair at some point so i've heard my hair gets so greasy i I'm never going to be able to do this. But you stop washing your hair and then it'll start producing a normal amount of oil so you never have to shampoo again. You can only put, you can just put like vinegar. Maybe Stefan's brushed his teeth so infrequently that the microbes are balanced. So infrequently, once a day, geez.

Yeah. Really, that feels very close to like like advocating pseudoscience we don't have to take care of our bodies they will take care of themselves yeah no i actually am a non-hair washer um and i did it like i switched over in like 2012 oh how often do you it was really greasy for like three months and then it like got normal. Do you never wash it anymore? No, I don't. I wash it like the hairdresser washes it. That's the only time it gets washed. And your hair looks great all the time.

I know! Interesting. So could you put other drugs in toothpaste? Would that actually work? I think that it would work, but it would have to be a particular kind of drug that is all about like absorption through a mucus membrane because you don't swallow toothpaste okay is it time for you to tell us your selections oh this is a really really hard one yeah so either we have series thunderstorm asthma where spring storms can explode some pollen and create easily ingestible or inhalable pollen grains. And then people get a surprise asthma attacks or mine,

uh, allergent, a toothpaste designed to decrease your, uh, your rhinitis and your hay fever by targeting your oral Langerhans cells. Tell me your answers. Three, two,

one. Sorry. Fuck me. God damn it. You asshole. tell me your answers three two one sorry sorry oh god damn you asshole i wanted us to both give a point to one and the other person i kind of wanted that too but i should have said hank because you hate toothpaste i want this toothpaste i do too i have point remorse now sorry no take backs i've got three hot ones coming in here jesus like all right. You don't have to defend yourselves. I'm fine. I'll survive. I have other sources of validation. My son is very cute. I'll survive. Yeah, you got those wet kisses to look forward to. That's true. All right. It's time for Ask the Science Couch. We've got a listener question for our couch of finely honed scientific minds.

This is from At The Merrier More. Is there a relationship between seasonal allergies and public horticulture, like the kinds of trees we plant in cities or their location? Oh, interesting question. Well, one thing I know is that different cities have very different rules and have had evolving rules as time goes on when it comes to what kind of plants, what kind of trees they plant. And my guess is that there's some example of some city somewhere that was like, let's just plant this kind of tree.

And it turned out being very bad for a small slice of the population. Yeah, that's basically what happened. Like, there is a relationship. Yeah, that's basically what happened. Like, there is a relationship, and it's just from thinking about some aspects of public hortic that public works projects should plant male trees to avoid dealing with seeds or fruit that need to be cleaned up. So it makes your life easier because in dioecious trees, which are split between male and female, like cedar or mulberry or ash trees, Only the female ones produce the seeds and flowers, and the male ones produce pollen. So that was one factor that was pushing towards the direction of male trees. And basically, this has led to an overwhelming amount of male trees in some cities,

which release a lot more pollen instead of having a balance of trees that are being fertilized and trees that are doing the fertilizing. The patriarchy strikes again. Yeah. It wraps up into a very nice, neat narrative with a very nice scientific article byline because you're like, ah, the trees are sexist too, and people will click. So people generally see this as part of a larger issue, which is just a lack of diversity of how we plant trees in urban areas. Sort of like you were saying, Hank, or guessing at, we just kind of decided what trees look nice, I think, in areas. And we're like, we're than thinking of a varied ecosystem and biodiversity in urban spaces. And we also just happen to pick some trees in some cities that are really big pollen sources as opposed to trees that are lesser pollen sources. And we just like, I don't know, don't manage them. And we just like, I don't know, don't manage them.

I don't know how much maintenance goes into public horticulture when you plant a tree and then leave it. And then people are just like, well, a tree is there now. Thank you to everybody who sent in your questions for the Science Couch. You can follow us on Twitter at SciShow Tangents, where we will tweet out topics for upcoming episodes every week. Thank you to at Fun Ash at Reality Minus Three and everybody else who tweeted us your questions this episode Sam buck final scores

I've got zero stefan's got one sam's got two and sari's got three Wow, sari has what I would call a commanding lead. Yeah. Yeah, sari does she's yeah at 49 Stefan at 46 sam at, and I'm at 41. At least we're all in the 40s still. But eight is a big gap to try and make up by the end of this season, you guys. It is only May. I could get hit by a bus and not be able to pilot. So that would be a really easy way to make that up.

That's the only way we're going to catch her, apparently. I guess I just insinuated that you might, like, call a hit on me. It would be great into the Hank's biography if he murdered you to win this game show.

Yeah, no, I could definitely incapacitate you without murdering you. Let's be honest. That's true. Okay. If you like this show and you want to help us out,

it's really easy to do that. First, you can leave us a review wherever you listen. That's helpful and helps us know what you like about the show. Second, tweet out your favorite moment from the episode so that we can see those. And finally, if you want to show your love for SciShow Tangents, just tell people about us.

And if you want to listen to SciShow Tangents ad-free, you can do that on Luminary. Thank you for joining us. I have been Hank Green. I've been Sari Reilly. I've been Stefan Chin. And I've been Sam Schultz. SciShow Tangents is a co-production of Complexly and the wonderful team at WNYC Studios. It's created

by all of us and produced by Caitlin Hoffmeister and Sam Schultz, who also edits a lot of these episodes along with Hiroko Matsushima. Our editorial assistant is Debuki Chakravarti. Our sound design is by Joseph Tuna-Medish, and we couldn't make any of this without our patrons on Patreon thank you and remember the mind is not

a vessel to be filled but a fire to be lighted but one more thing. In 2019, a team of researchers at the University of Chicago learned that gut bacteria are linked to allergies by giving mice a poop transplant from human babies that are allergic to cow milk. When mice were given poop from not allergic babies, they didn't develop an allergy. But when they were given poop from allergic babies, they did. Oh my God.

That's cute and sad and disgusting at the same time. Maybe I should get a saliva transplant from Stefan with his fresh, fresh non-brushed breath.