Speaker 1: July third.
Speaker 2: I woke that morning lethargic. The coffee didn't help my
Speaker 2: energy materialize, nor did it help clear away the clouds
Speaker 2: that had formed in my brain. My functionability was so
Speaker 2: affected that at one point I was sitting at my
Speaker 2: desk holding my head in my hands. That was the
Speaker 2: moment home seemed like the best place for me to be.
Speaker 2: Something was wrong, something was churning. That was the night
Speaker 2: the sickness hit. It reared its ugly head first by
Speaker 2: the expulsion of the contents of my stomach. I couldn't
Speaker 2: stop it from happening. Try as I may, no deep
Speaker 2: breath would stay the sick I was thwarted at every turn.
Speaker 2: Worship at the throne of the toilet God was inevitable.
Speaker 2: Dehydration became the scariest factor in this situation. I was
Speaker 2: losing more water than I could drink, partly because I
Speaker 2: had no desire to drink. I tried to work, I
Speaker 2: tried to eat. I slept on my sofa, I slept
Speaker 2: in my bed. I didn't get dressed. I barely ate,
Speaker 2: sitting my apartment alone, feeling the rumblings of my bowels,
Speaker 2: knowing that I was getting neither enough water nor nutrients
Speaker 2: was alarming. July eighth, Tuesday, a week since the beginning niagara,
Speaker 2: rushed again. All the happiness and confidence that had been
Speaker 2: present on Monday got flushed right down the toilet. I
Speaker 2: was scared, but I thought I just had to keep waiting.
Speaker 2: July twenty fourth, I sent an email to my doctor's
Speaker 2: office pleading my case, begging for a spot in his
Speaker 2: busy schedule.
Speaker 1: Three weeks after life.
Speaker 2: Took a drastic turn towards Liquidville, I had an appointment
Speaker 2: July twenty sixth Thursday. How was I going to catch
Speaker 2: the evacuating contents of my colon bowl bag? Milk joke,
Speaker 2: milk joke with the top cut off ew.
Speaker 1: A bag it was.
Speaker 2: Having finally figured out how to catch the liquid, I
Speaker 2: was ready now to the fun part. I was back
Speaker 2: on my knees at the throne. Only this time I
Speaker 2: was armed with a spoon small, taller than one.
Speaker 1: Used to feed a child. It's baby food.
Speaker 2: Thankfully, I only had to scoop about a quarter inch
Speaker 2: worth of waiste into each vial with a spoon that small,
Speaker 2: though it took scoop after scoop after scoop. July twenty
Speaker 2: ninth Sunday, I got a call from another doctor who
Speaker 2: works with my doctor. I'd been compromised. Small amounts of
Speaker 2: the parasite Girardia had been found a parasite. I had
Speaker 2: a parasite. After the initial shock, relief again washed over me.
Speaker 2: It was treatable with an antibiotic and I could actually
Speaker 2: start it that day, August fifth, Sunday morning, I took
Speaker 2: the final dose of antibiotic. The party is over. Girardia
Speaker 2: has left the building. As the host of a few
Speaker 2: human parties in my time, this was one of my
Speaker 2: least favorite. A host should have fun at their own party,
Speaker 2: but this party was full of selfish guests. They took
Speaker 2: and took and took from me, giving me nothing in
Speaker 2: return for my accommodations. That's a very you find the
Speaker 2: best first hand accounts, Aaron.
Speaker 3: That one is one of my favorites. I think it's amazing. Hi,
Speaker 3: I'm Aaron Welsh.
Speaker 1: And I'm Erin Almond Updike and.
Speaker 3: This is this podcast will kill you?
Speaker 2: And where did that first hand account come from?
Speaker 1: Aaron?
Speaker 3: So that came from a blog I found. It's Michael
Speaker 3: Roarer dot blogspot dot com, and it's from a August
Speaker 3: twenty twelve entry titled Giardia Ruined My gily Idea, which
Speaker 3: is an amazing title.
Speaker 1: It's a very good title.
Speaker 3: So, as you might have guessed, this week we are
Speaker 3: covering Giardia. Yes, we are the beautiful, beautiful protozoan parasite
Speaker 3: that will cause you to have horrible diarrhea.
Speaker 1: Yes, how fun, wonderful? What enjoy?
Speaker 2: This is kind of back to our standards in terms
Speaker 2: of disease, which I feel like we haven't done for
Speaker 2: a while. So I'm excited to like it's a it's
Speaker 2: a pathogen, and it makes you sick, like our first
Speaker 2: season ones. You know, I feel like we've been doing
Speaker 2: some off the wall crazy episodes lately.
Speaker 3: We did h Pylori, which was along the same lines.
Speaker 1: That's true. Yeah, no, it's hard to keep track.
Speaker 3: We have done a lot of sort of non traditional
Speaker 3: format type ones.
Speaker 1: I'm very excited for this.
Speaker 3: I'm excited to hear all about how it works. I
Speaker 3: don't really know how it works.
Speaker 1: Oh good, I can't wait to tell you.
Speaker 3: To honor Giardia. What are we drinking this week?
Speaker 2: Our quarantine this week is backpackers Delight.
Speaker 3: That's a good that's named because it is a very
Speaker 3: frequent infection in backpackers and many other people as well.
Speaker 3: But backpackers tend to get it from drinking contaminated streams,
Speaker 3: so make sure to filter your water. People. What's in
Speaker 3: backpackers delight.
Speaker 2: In this beverage. We have coconut water, you know, to
Speaker 2: rehydrate you after all that diarrhea, perf pineapple juice because
Speaker 2: it's tasty with coconut water, Ginger liqueur because that's good
Speaker 2: for your stomach, right fans, and vodka.
Speaker 3: Not good for your stomach, not good to rehydrate you,
Speaker 3: but essential for our quarantini. Yes, but our Placy Burrita
Speaker 3: does not contain alcohol, and we will post the recipe
Speaker 3: to both the Quarantini and the alcohol free Plasy Brita
Speaker 3: on our website and on our social media platforms.
Speaker 1: Yes we will.
Speaker 2: So before we start on today's episode, I actually have
Speaker 2: two corrections that I'd like to make that people emailed
Speaker 2: us about so very quickly. One is from I believe
Speaker 2: our last episode or second to last episode on encephalitis,
Speaker 2: so in that this is very embarrassing. Aaron, you mentioned
Speaker 2: that Robert de Niro like won the Academy Award, and
Speaker 2: I was like, oh, I'll fact check you. And I
Speaker 2: did that live during our recording of the episode, and
Speaker 2: I failed at fact checking you.
Speaker 1: I did it incorrectly. Robert de Niro did not win.
Speaker 2: Academy Award for Best Actor for Awakenings, but he was
Speaker 2: dominated he was nominated. Thank you to True Trivia Nerd
Speaker 2: Amelia for writing to.
Speaker 1: Let us know.
Speaker 3: Thanks Amelia, Yeah, keep on the path.
Speaker 2: Oscar Trivia Nerd self proclaimed.
Speaker 3: Okay.
Speaker 2: The other one is from our recent crossover with Indefensive
Speaker 2: Plants where we talked about aspirin. So as I was
Speaker 2: talking about all the various effects of aspirin, one of
Speaker 2: the effects of aspirin is that it's an antipyritic or
Speaker 2: an anti fever, so it reduces fever. Yeah, And in
Speaker 2: the episode I mentioned that this is due to its
Speaker 2: effects on vasodilation.
Speaker 1: I got over excited.
Speaker 2: Vasodilation can produce like local heat production, so like if
Speaker 2: you get a cut and then you have heat, the
Speaker 2: cut feels hot. That kind of heat production can be
Speaker 2: from the vasodilation. But systemically, aspirin is even cooler in
Speaker 2: that prostaglandins in your brain, which aspirin blocks the production
Speaker 2: of modulate the temperature center in your brain. So aspirin
Speaker 2: and other end sets actually work by reducing the temperature
Speaker 2: set point in your brain or blocking the increase in it,
Speaker 2: and that's how they reduce fever. So that's actually a
Speaker 2: much cooler mechanism, and I'm really bummed that I didn't
Speaker 2: mention it in that episode. So thank you very much
Speaker 2: to Kelly for emailing about this.
Speaker 3: Interesting.
Speaker 2: For anyone listening who has no idea what I'm talking about,
Speaker 2: that means you didn't listen to our ASPERN episodes, so you.
Speaker 1: Should go check it out. Hey, Okay, is that all
Speaker 1: the business that we have?
Speaker 4: Yeah?
Speaker 3: I think so.
Speaker 1: Well, then let's take a quick break and then get
Speaker 1: started on the biology.
Speaker 3: Let's do it. Girardia Okay. First of all, there are
Speaker 3: there's only one R in giardia.
Speaker 1: I know, I always call it girardia, butler giardia. Is
Speaker 1: that better?
Speaker 3: Yeah? It's like it's like I think it's the biology
Speaker 3: equivalent of saying nuclear.
Speaker 2: Okay, but I am always afraid that I'm gonna do that,
Speaker 2: so I never say that word in public. Let's say it,
Speaker 2: no girardia, okay, Beaver fever. That's what we're talking about today.
Speaker 2: So gr diasis, which is the disease caused by Girardia.
Speaker 2: Still doing it, Girardia giardia.
Speaker 1: There we go. Listen, it's fine.
Speaker 2: Giardiasis is the most frequently diagnosed intestinal parasite in the
Speaker 2: United States. That's my first fact for you. It's a massive,
Speaker 2: massive disease worldwide. It's common among travelers, it's common across
Speaker 2: the globe. So let's talk about what it is. Yeah,
Speaker 2: first of all, it's a parasite. It's a protozoan, which
Speaker 2: means it's a single celled organism. Protozoin is not a
Speaker 2: great word, but I used it.
Speaker 1: So there.
Speaker 2: It has three different names, three different species names that
Speaker 2: people call it, and it's all the same species, which
Speaker 2: is just to me the most annoying thing.
Speaker 3: Oh my gosh. It made it very difficult to research.
Speaker 1: Yeah.
Speaker 3: It has also changed throughout history multiple times.
Speaker 1: Oh, I'm not surprised about that at all.
Speaker 3: Yeah.
Speaker 2: So in medicine, they're more likely to call it Girardia lamblia. Yeah,
Speaker 2: but in the rest of everything other than like human medicine,
Speaker 2: it's Girardia duodenalis or Girardia intestinalis, which is kind of
Speaker 2: funny because duodenum is just the first part of your intestine,
Speaker 2: so it's kind of like those are interchangeable. But anyways, Girardia,
Speaker 2: I'm only saying one are erin.
Speaker 1: It's never gonna stop. I can't at this point, it's
Speaker 1: too late. It's a flagelet, so that means it has flagella,
Speaker 1: which we've talked about before that they use to move.
Speaker 2: And swim like a little tail, little tail in fact,
Speaker 2: not just one little tail. Girardia.
Speaker 1: God, I did it again, didn't I.
Speaker 2: Giardia has four sets of flagella, so it actually has
Speaker 2: eight that it uses to swim around, and it has
Speaker 2: two adorable little nuclei that look like eyeballs. Giardia is
Speaker 2: one of the cutest parasites of all time in my opinion.
Speaker 3: I'm just gonna say, I think it is the cutest
Speaker 3: one we've done so far.
Speaker 4: It is.
Speaker 2: Yeah, I think it's one of the top cutest ones
Speaker 2: ever because it really looks just like a little person's head. Yeah,
Speaker 2: they're so cute. Okay, So, because this is a parasite,
Speaker 2: we get to talk about the life cycle as far
Speaker 2: as parasites go. Girardia has a very simple life cycle
Speaker 2: compared to a lot of parasites. It has two different
Speaker 2: life cycle forms. Inside of your intestine, it's called a trophozoite,
Speaker 2: and this is the form that looks like what I describe.
Speaker 2: So it has two big old nuclei that look like
Speaker 2: eyes and eight floppy flagella that look like hair running
Speaker 2: off of it. So the trophozoite form can swim through
Speaker 2: your intestine stick on to your gut walls.
Speaker 1: And then they also.
Speaker 2: Divide by fission, so one trophozoite can actually replicate and
Speaker 2: replicate and replicate all on its own. They also then
Speaker 2: form a cyst phase, and the cyst phase is what
Speaker 2: you're most likely to poop out and what ends up
Speaker 2: in the environment. You poop out trophozoides too, But the
Speaker 2: cysts are really important in their life cycle because the
Speaker 2: cysts are very resistant to environmental stressors, so they can
Speaker 2: survive in water like ponds and rivers and storm drains
Speaker 2: and mountain streams for weeks to months, and then when
Speaker 2: an unsuspecting animal comes by to take a drink from
Speaker 2: that beautiful mountain spring, they're going to get a big
Speaker 2: old mouthful of Girardia cysts, and then inside of your
Speaker 2: body or the animal's body, that cyst will then split
Speaker 2: and produce two trophozoites and begin the cycle all over again.
Speaker 3: How cool, right, It's beautiful and simple. I like it.
Speaker 1: It's simple.
Speaker 2: Yeah, it's simple. It's straightforward. Another thing that's very cool
Speaker 2: about the cysts is that they're resistant to a lot
Speaker 2: of the common ways that we disinfect water, including chlorination
Speaker 2: and ozone nation or whatever you call it o zonification.
Speaker 3: But the chlorination is the chlorination that we use to
Speaker 3: treat the drinking water high enough to kill Giardia nod dude.
Speaker 2: You have to filter it or you have.
Speaker 1: To boil it. Oh, Girardia can live in your pool
Speaker 1: for up to like forty five minutes, not for a
Speaker 1: long time.
Speaker 3: Huh interesting yes.
Speaker 1: Mm hmmmmmmmm.
Speaker 2: And when you're infected with it, you can poop out
Speaker 2: between one and ten billion with a b cysts.
Speaker 1: Every time you.
Speaker 3: Poop ten billion is a lot of cysts.
Speaker 2: It's a lot of cysts. And guess how many cys
Speaker 2: it takes to get you sick.
Speaker 1: Probably one, well, usually about at least ten.
Speaker 2: Anyways, So that's why it's really really common to get
Speaker 2: girardia from contaminated water sources. That's one of the most
Speaker 2: common ways that we think about the transmission of giardia
Speaker 2: is from contaminated water. However, you can also get infected
Speaker 2: directly with trophozoites, which you're also pooping out at the
Speaker 2: same time that you poop out cysts. So other places
Speaker 2: that you can get infected are places that have a
Speaker 2: little bit less hygiene, like maybe daycare centers AHA, which
Speaker 2: are one of the most common places that we see
Speaker 2: outbreaks in for example the United States. Tiny humans poop
Speaker 2: their diapers, rub their hands in it, touch their friends faces.
Speaker 1: Everyone gets girardia.
Speaker 3: I mean, we see a lot of gi things, parasized
Speaker 3: pathogens that yeah, filthy, filthy, tiny hum yes.
Speaker 2: Okay, so let's talk about the symptoms. Symptoms can range
Speaker 2: from absolutely nothing entirely asymptomatic, just feeling normal, pooping out
Speaker 2: parasites without ever knowing that you're sick, to an acute
Speaker 2: illness that pretty much is self limited so you have
Speaker 2: diarrhea for a short time and then you get better,
Speaker 2: to some pretty severe chronic infections that can result in
Speaker 2: things like weight loss and malnutrition.
Speaker 3: Question yes, what proportion are asymptomatic versus symptomatic.
Speaker 1: That's a good question.
Speaker 2: I haven't found an exact number on that, and in
Speaker 2: the epidemiology section we'll talk a little bit about why
Speaker 2: that's hard. But it does seem to be a pretty
Speaker 2: high proportion, and it depends on what strains of the
Speaker 2: parasite are circulating in the area, because different strains are
Speaker 2: more likely to produce asymptomatic infections than symptomatic infections.
Speaker 1: It's a good question.
Speaker 2: So the variability and presentation, like I said, is partially
Speaker 2: due to the virulence of the pathogen, like which one
Speaker 2: you end up getting infected with, but it also has
Speaker 2: a lot to do with your own host immune factor,
Speaker 2: so just something about you that makes you more likely
Speaker 2: to get a symptomatic infection. And then also the infectious dose.
Speaker 2: So how many of those cysts did you actually swallow?
Speaker 2: So let's talk about how it causes these symptoms, because
Speaker 2: I'm really excited about it.
Speaker 3: Yes, me too.
Speaker 2: So the biggest symptom that you get with grdiasis is diarrhea.
Speaker 2: You also get generalized abdominal pain, maybe distinctionion, maybe it
Speaker 2: feels big. Maybe you get nausea and vomiting. You can
Speaker 2: definitely get that from infection with GRDA getting better, but
Speaker 2: diarrhea is the number one. So it turns out that
Speaker 2: we don't know everything about how it causes these symptoms,
Speaker 2: but we do know a few things. So first of all,
Speaker 2: Giardia does not invade your intestine wall, so unlike something
Speaker 2: like hookworm that when it gets in is going to
Speaker 2: make a hole in your intestine and like actually punch through,
Speaker 2: Giardia doesn't do that. What it does is it has
Speaker 2: on its ventral surface, so on the opposite side of
Speaker 2: where the flagella are, it has this adhesive disk, so
Speaker 2: it uses its flagella to swim through your intestine up
Speaker 2: to the wall of your intestine, and then it uses
Speaker 2: this adhesive disk to just suction cup on to the
Speaker 2: wall of your intestine and then do what and then
Speaker 2: absorb your food essentially and just live and replicate. And
Speaker 2: they replicate by fission, so you don't need to have
Speaker 2: multiple parasites to replicate. They just replicate the way that
Speaker 2: bacteria do. They just divide. They don't sexually reproduce.
Speaker 3: There is some question as to whether they do sexually reproduce.
Speaker 2: They definitely do recombination, which is cool.
Speaker 3: Yeah, there's some really interesting articles that are like sex
Speaker 3: in the dark. Does giardia have sex in the dark
Speaker 3: or something like that.
Speaker 1: It would be pretty dark in your intestine.
Speaker 2: Yeah.
Speaker 3: But so how long does an average giardia infection last
Speaker 3: if untreated?
Speaker 2: It's hard to say because in some cases it can
Speaker 2: cause a really prolonged chronic infection. If you just have
Speaker 2: an acute infection, it'll probably resolve in a number of weeks,
Speaker 2: but some people can be infected for months and months.
Speaker 1: Okay, So it's it's.
Speaker 2: A very difficult thing to put like a straight number
Speaker 2: on the incubation period. So the time from when you're
Speaker 2: first infected to when you start showing symptoms is usually
Speaker 2: between one and three weeks, okay, Okay. So, once this
Speaker 2: parasite is a onto your intestine wall, they have a
Speaker 2: number of different mechanisms that again none of them are
Speaker 2: completely well understood, but these are the things that end
Speaker 2: up resulting in you having potentially massive diarrhea. So first
Speaker 2: is that they basically induce the cells, the epithelial cells
Speaker 2: lining your intestine to start undergoing apoptosis, which is cell suicide.
Speaker 3: That's bad news, I know.
Speaker 2: So they don't directly kill any of your cells, but
Speaker 2: they kick somehow something that they're releasing causes those cells
Speaker 2: to start undergoing apoptosis and essentially dying. So what that
Speaker 2: is going to do is increase the permeability of that
Speaker 2: epithelial cell layer. So normally the cells of your intestine,
Speaker 2: you can imagine, are very tightly packed because you only
Speaker 2: want certain things to pass through. Right, you want to
Speaker 2: absorb nutrients but leave a lot of stuff in your intestine.
Speaker 2: You want to absorb water, but not too much water,
Speaker 2: et cetera. Right, it's a very fine balance the whole
Speaker 2: process of digestion. So you're basically poking a bunch of
Speaker 2: holes by destroying these cells lining your intestine. On top
Speaker 2: of that, they flatten the microvilli. So microvilli are the
Speaker 2: protrusions on your intestinal wall that increase surface area to
Speaker 2: be able to absorb water and nutrients. If you flatten those,
Speaker 2: then you decrease the surface area. Then you can't absorb
Speaker 2: that water and nutrient as well. So what that means
Speaker 2: is that in combination, when you have increased permeability and
Speaker 2: then you also have a decrease in the microvilli, you're
Speaker 2: completely messing up digestion essentially and absorption. What that means
Speaker 2: is that you're gonna end up with more stuff left
Speaker 2: in your intestine, and that's going to pull even more
Speaker 2: water out from your cells into your intestine instead of
Speaker 2: the other way. So that means that you're left with
Speaker 2: a watery stool. And that's what diarrhea essentially is. Right,
Speaker 2: It's like your food is passing through without actually getting absorbed.
Speaker 3: Does diarrhea have to be three times in twenty four
Speaker 3: hour period?
Speaker 2: This is that's a very good question. No, there's no
Speaker 2: official definition on how you classify diarrhea. Usually we say
Speaker 2: three stools in three loose stools in twenty four hours
Speaker 2: is when you can start being like, oh, I have
Speaker 2: diarrhea and not just like one bad poop or something
Speaker 2: like that.
Speaker 1: But it's not an official official definition.
Speaker 3: Okay.
Speaker 1: Yeah.
Speaker 2: On top of that, there have been studies that show
Speaker 2: that girardia giardia increases the rate of transit through your intestine,
Speaker 2: so your food is moving faster, and if it's moving faster,
Speaker 2: then your body can't absorb everything that's in it. So
Speaker 2: that's another way that it can cause diarrhea and malnutrition.
Speaker 2: Because if it's moving so fast that you can't absorb
Speaker 2: what's in there, boom, dude, no good hmm.
Speaker 3: I wonder if what you eat affects any of these things?
Speaker 2: Oh, what a good question. That's a very fun question.
Speaker 2: There's more, Okay, on top of all of that, there's
Speaker 2: some evidence that giardia causes hyper secretion of electrolytes. So
Speaker 2: on top of not allowing your intestine to properly absorb
Speaker 2: electrolytes and other things in your intestine, it causes the
Speaker 2: secretion of electrolytes from your cells into your intestine. And
Speaker 2: wherever electrolytes go, water goes.
Speaker 1: So now you have.
Speaker 2: Even more water going from your body into your intestine
Speaker 2: instead of the other way around.
Speaker 3: Definitely kicking you when you're down. It's not content to
Speaker 3: just like ringes a little bit. Is like no, completely dry,
Speaker 3: completely dry, burning some bridges there, right.
Speaker 2: And so that's all of sort of the diarrhea based
Speaker 2: things that giardia. Giardia does, Okay, okay, pretty cool.
Speaker 1: It's a lot and.
Speaker 2: We don't fully understand exactly how it happens, but it's
Speaker 2: easy to see how the few things that we do
Speaker 2: know can end up leading to maldigestion, so losing nutrients, malabsorption,
Speaker 2: not being able to absorb these nutrients. So if you
Speaker 2: if you are not able to fight this parasite off,
Speaker 2: and you have it chronically, it's easy to see how
Speaker 2: this can become a pretty serious infection that leads.
Speaker 1: To poor nutrition.
Speaker 3: Yeah.
Speaker 2: Now here's some things that I didn't really realize when
Speaker 2: I started researching this.
Speaker 1: In many cases, giardia is linked.
Speaker 2: To later development of a whole host of disease that
Speaker 2: we usually consider to be more autoimmune, like irritable bowel syndrome. Ah,
Speaker 2: there's a pretty strong association between infection with gerardia and
Speaker 2: irritable bowel syndrome.
Speaker 3: Okay.
Speaker 2: You also can get extra intestinal manifestations, so that means
Speaker 2: manifestations of this infection outside of your intestine, but not
Speaker 2: from the parasite because again, this parasite doesn't penetrate your
Speaker 2: intestine wall, so the parasite itself isn't traveling through your
Speaker 2: bloodstream and going anywhere else. But you can still get
Speaker 2: ocular symptoms, you can get like eye infection type symptoms.
Speaker 2: You can get joint pains, you can get skin rashes
Speaker 2: from gerardia.
Speaker 3: Infection does it have some sort of surface protein that
Speaker 3: mimics human surface protein.
Speaker 1: You're so so, I love it, Aaron.
Speaker 2: I don't know if it mimics human proteins, but there
Speaker 2: is thought that because the intestinal wall permeability is increased,
Speaker 2: anigens from Gerardia are being sucked into your bloodstream and
Speaker 2: those are what's causing the extra intestinal manifestation. So it's
Speaker 2: not the parasit itself, but it's some of their surface
Speaker 2: protein that make it into your bloodstream.
Speaker 3: How cool, that's cool, that's cool. That's horrible.
Speaker 1: That's horrible.
Speaker 3: I have a question about a symptom, Yes, rotten egg burps.
Speaker 2: Yeah, I heard you mentioned that earlier, sulfur burps. M
Speaker 2: I didn't come across that as a thing in researching this,
Speaker 2: but I mean, it's totally screwing up your gut.
Speaker 1: So yeah, I just.
Speaker 3: Wondered what specifically would be causing the sulfur smell from that.
Speaker 1: Yeah, that's a good question. I don't know, huh.
Speaker 2: The good news about this parasite is that it's pretty
Speaker 2: easy to treat. Yeah, basically, just go on a course
Speaker 2: of antimicrobials, usually metronitozol or nitozoxinide. Another just there's a
Speaker 2: couple different classes of antimicrobials that we can use that
Speaker 2: are very effective so far at treating it. The problem is,
Speaker 2: reinfection is really really common, especially if the reason that
Speaker 2: you got infected in the first place was that sanitation
Speaker 2: isn't great where you live or something like that. If
Speaker 2: you got infected while you were out backpacking, you're probably
Speaker 2: less likely to get.
Speaker 1: Reinfected once you clear that infection.
Speaker 2: But anyways, I'll talk a little bit more about that
Speaker 2: all in the epidumiology section. But anyways, that's the biology
Speaker 2: of GRDA.
Speaker 3: I like it on the surface straightforward, but I think
Speaker 3: there's a little bit more interesting things going on.
Speaker 2: Yeah, and it seems like there's very very cool research
Speaker 2: being done on figuring out exactly how this pathogen ends
Speaker 2: up causing all these different manifestations and exactly how it's
Speaker 2: affecting all the different cell layers in your intestine.
Speaker 1: It's very cool.
Speaker 2: We at this point don't even know exactly how it adheres.
Speaker 2: We know there's a bunch of different proteins that are
Speaker 2: interacting on that ventral disc to suction it on, but still, well.
Speaker 3: It's surprising that it's sort of an up and coming
Speaker 3: field of research, considering that it's so widespread.
Speaker 2: Yeah, yeah, Shall we take a quick break, and then
Speaker 2: I want you to tell me all about how we
Speaker 2: got here and where the heck this parasite came from.
Speaker 3: Okay, I'll do. I'll try my best. Before I get started,
Speaker 3: I just want to admit that when I was researching
Speaker 3: this history, I had a bit of a tough time.
Speaker 3: And you know this because I complain to you in excess.
Speaker 1: I wouldn't say excess.
Speaker 3: Well, I did complain about it, yeah, which is nice
Speaker 3: to have this be something to complain about instead of
Speaker 3: many other things. But it shows that my life is
Speaker 3: pretty good. But the thing is is that there isn't
Speaker 3: a super cut and dry history of giardia in humans,
Speaker 3: which is strange to me because it is one of
Speaker 3: the most prevalent waterborne infections and causes of diarrhea around
Speaker 3: the world today and has probably held that title for centuries.
Speaker 3: Giardia doesn't have the glitz and glam of a pathogen
Speaker 3: like cholera. It's more of a background parasite, always kind
Speaker 3: of causing a bit of trouble here and there, but
Speaker 3: rarely headline worthy of glitz.
Speaker 1: And glam of color, and anyone.
Speaker 3: Said that about cholera before, not until this podcast. That's
Speaker 3: why we're here. Yeah, but the history of Giardia can
Speaker 3: be condensed pretty much into a few sentences, and in
Speaker 3: most of the papers that I skimmed, that's all that
Speaker 3: it was. But that wouldn't really make for a very
Speaker 3: good podcast episode in my opinion. So I kept digging deeper.
Speaker 3: And as I dug more and more into the history
Speaker 3: of Giardia, I found that it was part of a
Speaker 3: largest story that I could tell, one about a new
Speaker 3: way to see the world. Ooh, okay, just bear with me.
Speaker 3: I hope this is okay.
Speaker 1: I love it already.
Speaker 3: Giardia was first described in sixteen eighty one by the
Speaker 3: famous Anthony von Lavenhook when he was examining his diarrheal
Speaker 3: poop under a microscope of his own making. Yeah, that's
Speaker 3: the kind of guy he was. I think he would
Speaker 3: have been a fan of TP. We would have been friends,
Speaker 3: for sure.
Speaker 1: Yeah.
Speaker 3: Possibly. And so this isn't the first time that we've
Speaker 3: come across laven Hook during the podcast. And I remember
Speaker 3: this because every time I talk about him, I have
Speaker 3: to try to figure out how to say his name,
Speaker 3: and I end up just crossing my fingers and hoping
Speaker 3: for the best. But mostly when I've mentioned laven Hook,
Speaker 3: it's just been in passing. So this guy named laven
Speaker 3: Hook saw this thing, and then I would move on
Speaker 3: to another part of the history. But for this episode,
Speaker 3: I really wanted to go more into this period of
Speaker 3: science and what a critical role the microscope played in
Speaker 3: the development of many different scientific fields and even more importantly,
Speaker 3: maybe or more interestingly, our perception of the world on
Speaker 3: the surface. Anthony van Lavenhook may not have been the
Speaker 3: person you would have predicted would discover and develop a
Speaker 3: new way to see the world. He was born in
Speaker 3: sixteen thirty two in Delft in what was then the
Speaker 3: Dutch Republic. He was a cloth merchant and a bureaucrat
Speaker 3: for most of his life, and throughout a lot of
Speaker 3: his life he didn't really seem preoccupied or even that
Speaker 3: much interested in the natural world. It was only later
Speaker 3: that he started to dabble in lens making and maps
Speaker 3: and collecting of odd specimens and having a curiosity's cabinet,
Speaker 3: which was by the way, all the rage of course,
Speaker 3: in the Dutch Republic in the mid sixteen hundreds.
Speaker 1: The curiosity's cabinet, of course.
Speaker 3: Yes, yes, I want a curiosity's cabinet. I'm getting there, okay.
Speaker 3: One warm August day in sixteen seventy four, Lavenhook was
Speaker 3: relaxed and maybe a tad restless. Though, now that he
Speaker 3: was retired and no longer had his thread counts to
Speaker 3: keep him occupied, he had turned his sites toward natural
Speaker 3: science pursuit, which often pulled him outside into the sun.
Speaker 3: On this particular August day, he does something extraordinary, something
Speaker 3: that would go on to revolutionize our understanding of the
Speaker 3: world around us. He had taken some water from a
Speaker 3: lake that was a couple hours walk away, and he
Speaker 3: put it in a lens and tube mechanism that he
Speaker 3: had made himself an early microscope. Even though the lake
Speaker 3: was cleaned, or at least believed to be clean by
Speaker 3: the people who lived near the lake, the drop of
Speaker 3: lake water that he examined is teeming with life not
Speaker 3: visible to the human eye on its own. The motion
Speaker 3: of these animal couoles and the water was so swift
Speaker 3: and so various downwards and roundabout that I confess I
Speaker 3: could not but wonder at it. He said about this lakewater,
Speaker 3: This marks the first time in history, probably that humans
Speaker 3: had gotten a glimpse of an entirely new world not
Speaker 3: visible to the naked eye. Discoveries like this don't often
Speaker 3: happen in isolation, although they're often told in that way.
Speaker 3: There's almost always some kind of build up that has
Speaker 3: made at the right time in place for a particular
Speaker 3: development to take place, or at least that's how we
Speaker 3: can see it in retrospect. So in this case, what
Speaker 3: was going on in the world in sixteen seventy four
Speaker 3: that had set the stage for laven Hook's discovery. So
Speaker 3: at the time that laven Hook was looking through his
Speaker 3: microscope at this previously undiscovered world, the scientific world was
Speaker 3: undergoing something of a revolution, and maybe more accurately, was
Speaker 3: being born. Whereas in the past it was enough for
Speaker 3: someone to rely on the words or the writings of
Speaker 3: those ancient philosophers who had come before, the trend was
Speaker 3: shifting towards emphasis on data that you obtained empirically through observations,
Speaker 3: and this often meant personally observing the phenomenon that you
Speaker 3: were interested in, then publishing your observations, and then having
Speaker 3: other people independently confirm what you had seen. But these
Speaker 3: people who were not yet called scientists needed tools that
Speaker 3: would enable them to accurately measure whatever it was they
Speaker 3: were interested in and produce consistent results across other observers.
Speaker 3: And as we know, necessity is the mother of invention,
Speaker 3: and during the seventeenth century a lot of invention happened.
Speaker 3: So all kinds of empirical tools were developed that expanded
Speaker 3: the realm of human observation. The thermometer, the barometer, the
Speaker 3: pendulum clock, the telescope, the microscope. These things were all
Speaker 3: either invented or developed to the point where they were
Speaker 3: in almost wide use.
Speaker 1: That's so cool, it's so cool.
Speaker 3: And these because these tools also they turned these personal
Speaker 3: experiences into impersonal numbers. The subjective in describing natural events decreased,
Speaker 3: but the words that were used to describe these observations
Speaker 3: became more specific and more relatable across cultures and languages.
Speaker 2: Oh wow, I never even thought about that aspect of it.
Speaker 3: Yeah, it really did sort of flatten the globe, I guess,
Speaker 3: or in terms of in terms of advancing knowledge and
Speaker 3: saying to be able to say how hot is it?
Speaker 3: It's pretty hot, or it's this many degrees? Although here
Speaker 3: I am you know Celsius and Imperial. That's okay, we
Speaker 3: won't get in. We have calculators now, yeah, exactly, we
Speaker 3: have Google, Google filth. Yeah. This fascination with empiricism extended
Speaker 3: beyond those that were studying mathematics or geography or the
Speaker 3: natural world. This time, so like the mid sixteen hundreds,
Speaker 3: the sixteen hundreds to seventeen hundreds was a time of
Speaker 3: observation of recording. Surveyors would map the land while astronomers
Speaker 3: mapped the sky, and painters use camera obscuras to record
Speaker 3: scenes from life, while natural historians recorded the plants and
Speaker 3: animals around them. In this time, also, the boundary between
Speaker 3: artists and scientists was thin, so some of those that
Speaker 3: consider themselves catalogers of the natural world had been trained
Speaker 3: in painting or drawing, because how else could you relay
Speaker 3: what you were seeing or observing. Right and Dutch artists
Speaker 3: in particular were becoming more detail oriented, with the tendency
Speaker 3: for art during this time to be more about what
Speaker 3: is directly observed, rather than telling a story or idealizing
Speaker 3: a person or place by ignoring or glossing over the flaws.
Speaker 3: This general focus on recording and realism during this time
Speaker 3: is I think a really important part of the story
Speaker 3: of microscopy, because for the first few decades of its existence,
Speaker 3: the microscope was primarily used to demonstrate the wonders of
Speaker 3: the natural world. Look at this super cool grasshopper. Look
Speaker 3: at this tiny mite living in your cheese.
Speaker 1: This animal keule, what does he call them?
Speaker 3: Animal cule? Yeah, And while telescopes shortened distance, bringing far
Speaker 3: away things closer to the eye, those things were already
Speaker 3: generally known to humans. Just far away. You could see
Speaker 3: that that star, or that planet or that tree was there,
Speaker 3: but if you look at it through the telescope, it's closer.
Speaker 3: But microscopes, on the other hand, revealed this whole new world.
Speaker 3: And this, I feel like, would have completely shifted the
Speaker 3: perception of the natural world and what role humans play
Speaker 3: in that. Yeah, it's really hard to imagine.
Speaker 2: It blows my mind, quite honestly.
Speaker 3: It's impossible. It really is unimaginable, Like to wonder at
Speaker 3: what that would be like to day, would be like
Speaker 3: discovering that we live in the tear drop of a giant.
Speaker 1: I feel like it.
Speaker 2: I mean, this is not as extreme, but I feel
Speaker 2: like it was how I felt the first time I
Speaker 2: ever went scuba diving. Mmm, I like sitting at the
Speaker 2: bottom of a kelp forest and looking up you realize
Speaker 2: just how like it's an entirely different world. And I
Speaker 2: feel like it's a similar. Look if you have no
Speaker 2: concept that things this small exist and then you look
Speaker 2: in a drop of water and you see this, it's like,
Speaker 2: what like it's yeah, yeah, that's the closest I can come.
Speaker 3: I've read before that people who go to space astronauts
Speaker 3: and then they look down at the Earth, that their
Speaker 3: perception of world, of life, human of humanity is forever
Speaker 3: changed by that in a way that's yeah, that you
Speaker 3: can't imitate or mimic. And I kind of wonder whether
Speaker 3: that was it was similar to that being some of
Speaker 3: the first people to say, oh, like, there's a whole
Speaker 3: new world here and not just being told or seeing
Speaker 3: pictures of it.
Speaker 1: I can't stop singing a whole new.
Speaker 2: World every time it, by the way, every single time.
Speaker 3: It's amazing. Yeah, but yeah, these microscopes could could reveal
Speaker 3: the tiny, tiny, little intricacy of a flea's leg, and
Speaker 3: how beautiful it could be to look at a spider's eye. Oh,
Speaker 3: it's amazing.
Speaker 1: It's incredible.
Speaker 3: Robert Hook was one of the first people to develop
Speaker 3: or to use the microscope in observation, and he had
Speaker 3: this groundbreaking book called Micrographia micro Graphia that displayed the
Speaker 3: exteriors of these tiny creatures or of everyday objects magnified
Speaker 3: to sizes never before seen. And think he had a
Speaker 3: fold out of a flea, for instance.
Speaker 1: Oh, yeah, I've seen that. I've seen that. It's incredible.
Speaker 3: Yeah, I want to get that coffee table book. Yes,
Speaker 3: I wonder if they make it. But the simple description
Speaker 3: of these things soon wasn't seen as enough. Some people
Speaker 3: were like, Okay, these microscopes are incredibly powerful tools that
Speaker 3: should be used to explore the inner workings of both
Speaker 3: living and non living things. How do things work? Yeah,
Speaker 3: just to use them only on making pretty drawings seemed
Speaker 3: like a waste to a lot of people. Okay. So
Speaker 3: Laven Hook would not have been unfamiliar with microscopes or
Speaker 3: at least magnification using lenses, because as a cloth merchant,
Speaker 3: he had to inspect his fabric for thread count, So
Speaker 3: it makes sense that he would have maybe tried experimenting
Speaker 3: with lenses, especially considering the trend that had swept society
Speaker 3: because people were obsessed, fascinated by lenses.
Speaker 1: Oh that is so funny.
Speaker 3: They wanted to look at the mites crawling in their bread,
Speaker 3: the fleas and their dogs, anything and everything. By the
Speaker 3: mid sixteen hundreds, you could find lens stores in every marketplace,
Speaker 3: and wearing glasses even if you didn't need them, could
Speaker 3: be considered fashionable.
Speaker 1: Okay, that's still fashionable today, isn't it. So nothing has changed.
Speaker 3: Lens crafting varied in technique and quality, and imperfections in
Speaker 3: the glass led many people, including laven Hook, to experiment
Speaker 3: with making lenses of their own. After retiring from the
Speaker 3: cloth trade, laven Hook started to venture into lens crafting,
Speaker 3: first with bead lenses, which is where you melt the
Speaker 3: end of a glass rod over a flame and then
Speaker 3: you draw out a thread of glass, cutting off the
Speaker 3: end when it becomes a bubble. What yep. And so
Speaker 3: from these bead glasses you could make powerful lenses, but
Speaker 3: with very short focal lengths.
Speaker 1: Huh.
Speaker 3: And because you were using flame to create them, you
Speaker 3: were going to make a lot of duds before getting
Speaker 3: a new one.
Speaker 1: Okay.
Speaker 3: So after bead lenses, laven Hook moved onto grinding and
Speaker 3: blowing glass. His obsession or patients maybe or maybe it
Speaker 3: was both rewarded him and his microscopes ended up being
Speaker 3: some of the best known during this time in his life.
Speaker 3: He made loads of microscopes of varying magnification and construction
Speaker 3: and quality, and estimated five hundred and sixty six total wow,
Speaker 3: of which sadly only nine survive, eight with lenses.
Speaker 2: I thought, I remembered you saying that, like, he's got
Speaker 2: a whole cabinet full of somewhere that just disappeared from Yep.
Speaker 3: It disappeared like he left it to the Royal Society
Speaker 3: after his death and somebody went to look at it
Speaker 3: in the mid eighteen hundreds and then the Royal Society
Speaker 3: was like, uh, we don't know where it is.
Speaker 1: That's the most depressing.
Speaker 3: Anyone who's thrifting or antique hunting in England. I think
Speaker 3: is where the is where the cabinet was last seen.
Speaker 3: Keep an eye, yeah, man, I think a lot of
Speaker 3: the other ones to the glass tubes were melted down,
Speaker 3: not the glass tubes, the gold tubes melted down for gold.
Speaker 4: Ugh.
Speaker 3: Yeah. But of those surviving lenses, of the eight ones
Speaker 3: that have lenses, the magnification range from sixty nine times
Speaker 3: to two hundred and sixty six times. What but he
Speaker 3: may have achieved even higher magnification up to five hundred times.
Speaker 1: That's bananas.
Speaker 3: He was probably the first person to see bacteria. He
Speaker 3: saw some on peppercorns.
Speaker 2: Wow, I had no idea that he Wow.
Speaker 3: Yeah, two twenty five is a lot already, I know,
Speaker 3: it's amazing.
Speaker 1: That is very cool.
Speaker 3: So Hook had shown the world this beauty and intricacy
Speaker 3: of things that humans already knew to exist, like the
Speaker 3: fold out flea. But Leaven Hook would reveal a whole
Speaker 3: new world, a brand new world. I'm just gonna keep saying,
Speaker 3: whole new world new. There we go that previously had
Speaker 3: been completely unknown. And he started out like Hook observing
Speaker 3: visible things in miniature. But when he stuck some lake
Speaker 3: water under his scope is when he discovered that this
Speaker 3: microscopic teeming life that was present in not just lakewater,
Speaker 3: but rainwater and everything else.
Speaker 1: Yeah.
Speaker 3: It's hard to say whether even Laven Hook realized at
Speaker 3: first the magnitude of his discovery. He published his observations,
Speaker 3: but they were buried around twenty pages in his manuscript
Speaker 3: on other microscopic observations of things like the working of
Speaker 3: the eye, and so his description of this new unseen
Speaker 3: world wasn't met with much acclaim, and he kept sort
Speaker 3: of writing in with new observations, saying, oh, remember when
Speaker 3: I found this, like tons of microscopic life and rainwater.
Speaker 3: They were very small. They were very small. And finally
Speaker 3: he was like, did no one read this? Probably not, No.
Speaker 1: One makes it twenty pages in Anthony.
Speaker 3: Uh uh, come on man. After his repeated writings, people
Speaker 3: finally did start to take notice of what he had said,
Speaker 3: and they were like, eh, really, come on. It was
Speaker 3: there was a little bit of disbelief happening because Lavean
Speaker 3: Hook was describing a world that was unimaginably small. He
Speaker 3: was describing living creatures ten thousand times smaller than the
Speaker 3: smallest thing perceivable by the naked eye. Jeez, it sounded
Speaker 3: like a fanciful story made up by a very creative
Speaker 3: and bored person and retired du Yeah. The credibility of
Speaker 3: his findings also wasn't helped by his extreme possessiveness of
Speaker 3: his instruments. He was famous for jealously guarding the secrets
Speaker 3: of how he made his powerful microscopes, and this was
Speaker 3: super frustrating to the Royal society, who had no patience
Speaker 3: for people obscuring the methods behind their discoveries acting like magicians.
Speaker 3: And that's I think reasonable, yecause how can you take
Speaker 3: someone at their word who claims that the water you drink,
Speaker 3: the rain that falls contains billions trillions of small animals invisible.
Speaker 2: To the naked eye, right when it sounds absurd and
Speaker 2: they won't tell you how they made the thing in
Speaker 2: order to look at it, like that's right, yeah, yeah.
Speaker 3: And he, you know, he recognized that this was standing
Speaker 3: in the way of the world accepting his immense discovery,
Speaker 3: but he was too stubborn to do anything about it.
Speaker 3: So what he did was he was like, all right,
Speaker 3: now you all can come here to look through the
Speaker 3: lens for yourselves. And they were like, we're not going
Speaker 3: to do that, man, we're in England. We're not going
Speaker 3: to go all the way to Delft. That's not that far.
Speaker 3: But and then so he was like, okay, fine, stay there,
Speaker 3: don't come here. He got people to write, like to
Speaker 3: sign affidavits saying that they had seen this in his scopes,
Speaker 3: like okay, it's a little bit better, but we're still
Speaker 3: not content. So then the Royal Society was like, all right,
Speaker 3: we just need somebody else to do this. So then
Speaker 3: they pulled Robert Hook away from his workings of circulatory
Speaker 3: systems and respiratory systems because Hook had by now moved
Speaker 3: on from microscopy. And they were like, okay, Bob, will
Speaker 3: you try to replicate these findings?
Speaker 1: Bob, can you help us out here?
Speaker 3: And Bob did so he did eventually after a little
Speaker 3: bit of trying, find these animal cools that leaven Hook
Speaker 3: had supposedly seen. So that was pretty big step. His
Speaker 3: world was confirmed, and this discovery caused this major shift.
Speaker 3: Once it was confirmed by Hook, this it was reported,
Speaker 3: and it causes major shift in human perception because suddenly
Speaker 3: the world both grew and shrank. Some people were comforted
Speaker 3: by it, taking it as evidence of a divinely created world,
Speaker 3: while others took a more nihilistic view. Yeah. For his part,
Speaker 3: laven Hook didn't stop at examining lake water or rain water.
Speaker 3: Once he had gotten a glimpse of those microscopic worlds
Speaker 3: teeming with life, there was no substance off limits. He
Speaker 3: looked at his own blood yours toothplaque pus gunk from
Speaker 3: between his toes after not taking off his stockings for
Speaker 3: two weeks.
Speaker 1: Pretty gross.
Speaker 3: Made that gross. He also looked at earwax semen, and
Speaker 3: of course his own feces, which is of course where
Speaker 3: he first spotted his sweet little Giaradia. One of the
Speaker 3: things that I think is really fascinating about the development
Speaker 3: of microscopy is how long it seemed to take for
Speaker 3: people to make the connection between the little microscopic animal
Speaker 3: cooles seen in sources of drinking water and diarrheal disease.
Speaker 3: Even Lavenhok was so fond of his little animal cools
Speaker 3: that he would never have accused them of causing the
Speaker 3: diarrhea in which he found Giardia.
Speaker 1: That's very adorable.
Speaker 3: He loved them.
Speaker 1: They really found them in his poop, Yes.
Speaker 3: He loved I mean he loved the ones in rainwater.
Speaker 3: He loved the ones he missed them when he went away.
Speaker 1: That's very adorable.
Speaker 3: Yeah, okay, So going into Giardia a little bit now.
Speaker 3: It took almost two hundred years after laven Hook first
Speaker 3: observed Giardia in sixteen eighty one for it to get
Speaker 3: an official name, and even then it would be another
Speaker 3: one hundred years or so before it was officially recognized
Speaker 3: as actually causing disease in humans.
Speaker 1: Does that mean we're talking about the nineteen hundreds, yes?
Speaker 3: What Yeah? So in eighteen fifty nine, villain Duson lambole
Speaker 3: I probably said that wrong. Was a Czech scientist and
Speaker 3: he was examining the stool of a child found it
Speaker 3: teaming with Giardia protozoa. He called them circomonas in testinalis,
Speaker 3: but the name eventually was changed to Giardia Lamblia to
Speaker 3: honor Lambele and Alfred Gillard, who also described the parasite.
Speaker 3: So to put the official discovery of Giardia in eighteen
Speaker 3: fifty nine into our history of disease timeline, that happened
Speaker 3: just a few years after the infamous Broad Street cholera
Speaker 3: epidemic in London, and as we remember from that cholera episode,
Speaker 3: the theory of mi asthma was in full swing at
Speaker 3: that time. Of course, over the next few decades people
Speaker 3: would use microscopes to develop the field of germ theory
Speaker 3: linking a parasite or pathogen to the site of infection,
Speaker 3: and microscopes were also used to develop so many other fields,
Speaker 3: both in biology and chemistry, in physics and everything. It's
Speaker 3: they're been amazing.
Speaker 1: I don't know why.
Speaker 2: I was expecting that since it's a parasite, it somehow
Speaker 2: would have been earlier. But I mean, it's it's still
Speaker 2: I mean, it's still a microscopic. It's still you know,
Speaker 2: it's like malaria.
Speaker 3: It's like, yeah, well it's still microscopic. But even when
Speaker 3: it was recorded and given a name in eighteen fifty nine,
Speaker 3: it was still just seen as an organism, right, not
Speaker 3: necessarily a parasite.
Speaker 2: Yeah.
Speaker 1: God, which is so interesting.
Speaker 3: And I think so I yeah, I was thinking about
Speaker 3: this and I'm like, Okay, that seems like one of
Speaker 3: the easiest links to uncover between microbe and disease. Yeah,
Speaker 3: but it didn't seem like it got a lot of focus.
Speaker 3: And maybe that's because it was almost ever present and
Speaker 3: didn't necessarily cause a lot of obvious mortality or epidemics,
Speaker 3: even though it did cause occasional epidemics.
Speaker 4: Yeah.
Speaker 2: And if you can have just i mean, probably everyone
Speaker 2: was infected with it, so you're testing everyone's poop and
Speaker 2: not everyone is having diarrhea, you're still going to see
Speaker 2: giardia in everyone's poop, So you wouldn't think, Yeah, yeah,
Speaker 2: that makes sense.
Speaker 3: So it's a little bit of a harder Yeah. And
Speaker 3: there were some researchers in the early nineteen hundreds that
Speaker 3: claimed that giardia was a common cause of diarrhea, and
Speaker 3: they had conducted experiments on both humans and animals to
Speaker 3: observe the effects of the infection, and they also had
Speaker 3: recorded their observations of gardioceis and English soldiers in like
Speaker 3: World War One, I think, but interest in the parasite
Speaker 3: seemed to wane throughout the twentieth century. So the WJO
Speaker 3: officially declared it a human pathogen or parasite in nineteen
Speaker 3: eighty one, but it wasn't officially recognized as fulfilling all
Speaker 3: the pastas until nineteen eighty seven, and even after that
Speaker 3: it was still debated whether whether some some cases of
Speaker 3: disease could be attributed to the parasite.
Speaker 1: Yeah, are surprised even yeah. Wow.
Speaker 3: And this decline and interest I think was possibly maybe
Speaker 3: due to the massive reduction in waterborne infections throughout the
Speaker 3: developed world as water filtration increased. So I couldn't really
Speaker 3: find any good numbers for global prevalence of giardia throughout history.
Speaker 3: And that's maybe because it was only recently recognized as
Speaker 3: a human parasite, and possibly because it dropped off in
Speaker 3: places that had the highest amounts of research funding. But
Speaker 3: even though I can't give you hard numbers, I can
Speaker 3: make some guesses, which is a statement that the seventeenth
Speaker 3: century Dutch society would have hated. It's very non empirical.
Speaker 3: Giardia has probably infected humans for Lena, as is evidenced
Speaker 3: by its global distribution and prevalence likely increased as humans
Speaker 3: settled and population density increased as water treatment and filtration
Speaker 3: became more widespread. In the first half of the twentieth century,
Speaker 3: cases of intestinal diseases declined in many places, as did
Speaker 3: mortality from water borne diseases. So, for instance, in nineteen hundred,
Speaker 3: if you lived in the US, you had a one
Speaker 3: in twenty chance of dying of a gastrointestinal infection before
Speaker 3: you were seventy years old.
Speaker 1: WHOA, yeah, a lot.
Speaker 3: By nineteen forty that was a one in three thousand,
Speaker 3: three hundred and thirty three chance, and in nineteen ninety
Speaker 3: a one in two million.
Speaker 1: Chants wow.
Speaker 3: But for much of the world, the risk of dying
Speaker 3: of a waterborne disease remains staggeringly high, and giardia remains
Speaker 3: one of the most common infections and causes of morbidity
Speaker 3: out there. So Aarin, tell me exactly what we're dealing
Speaker 3: with in Gardi.
Speaker 2: It's ada.
Speaker 1: I'd love to.
Speaker 2: We'll take one more quick break. It's funny that you
Speaker 2: said you couldn't find good numbers on giardia throughout history,
Speaker 2: because I couldn't find good numbers on girardia today.
Speaker 3: What's the deal?
Speaker 1: End of our episode? Just kidding.
Speaker 3: This is the most slept on parasite out there.
Speaker 2: So this is a disease that is so widespread that
Speaker 2: on the World Health Organization website page about grdiasis, it
Speaker 2: just says distribution colon worldwide. Wow, like legit, that's what
Speaker 2: it says. Somm. According to the CDC, nearly two percent
Speaker 2: of adults and six to eight percent of children in
Speaker 2: developed countries will be infected at some point in their
Speaker 2: lives with giardia, and nearly thirty three percent of people
Speaker 2: living in developing countries will have been infected at some
Speaker 2: point in their lives.
Speaker 3: And we still don't exactly know how it causes disease.
Speaker 2: Well, apparently it was like thirty years ago that we
Speaker 2: decided we'll call it a human pathogen. So when you
Speaker 2: hear that, it's not that surprising.
Speaker 3: That's yeah, that is that's true. Yeah. Wow.
Speaker 2: So it's by a long shot the most common human
Speaker 2: intestinal parasite diagnosed in the US. I did find a
Speaker 2: few numbers in one of the papers that I read
Speaker 2: reported at least a few numbers, so I'll give those
Speaker 2: to you. Between two thousand and six and two thousand
Speaker 2: and eight, in the US there were at least twenty
Speaker 2: thousand cases reported annually, and the estimated actual number was
Speaker 2: closer to two million. And that's US, okay, And for
Speaker 2: you in Finland, In Finland, Norway and Sweden again in
Speaker 2: like the mid two thousands, they estimated that for every
Speaker 2: single case that was reported, there were likely between two
Speaker 2: hundred and fifty and eight hundred and fifty actual cases
Speaker 2: that went unreported.
Speaker 1: Wow. Yeah.
Speaker 2: And then throughout Europe the numbers really vary, like hundreds,
Speaker 2: two thousands to tens of thousands reported every year. It's
Speaker 2: so we just absolutely do not have a good handle
Speaker 2: on how many people are actually infected at all.
Speaker 3: It's a real tip of the Iceberg situation.
Speaker 2: And here's where it gets even more fun and even
Speaker 2: more tip of such a large iceberg erin this was
Speaker 2: thrilling to get to read. One of the biggest things
Speaker 2: that we absolutely do not have a handle on that
Speaker 2: we're still trying to figure out is in regards to
Speaker 2: how much overlap there is between cycles of this disease.
Speaker 3: Between cycles, Oh, let's.
Speaker 1: Talk about it.
Speaker 2: So yes, As it turns out, there are several distinct
Speaker 2: cycles in which we can identify that Giardia circulates. There's
Speaker 2: wildlife cycles, so wildlife poop in the wild and infect
Speaker 2: other wildlife. Okay, that's a wildlife cycle of disease. There's
Speaker 2: livestock cycles where live stock on a farm poop on
Speaker 2: that farm and infect all the live stock on that farm.
Speaker 2: That's a livestock cycle. There's domestic animal cycles like dogs
Speaker 2: and cats infecting each other. And then there's human cycles
Speaker 2: where humans poop and infect each other. The question that
Speaker 2: we don't know is how much overlap is there between
Speaker 2: these cycles and what kind of overlap is it. Are
Speaker 2: things being directly transmitted between wildlife and humans. Is it
Speaker 2: all waterborne transmission between wildlife and humans, Is it more
Speaker 2: cycling between livestock and humans, or between humans and livestock.
Speaker 2: Which direction do these spillovers occur?
Speaker 1: And are there distinct.
Speaker 2: Species or subspecies of Giardia being transmitted between these different
Speaker 2: groups or is it all the same parasite.
Speaker 3: We have no idea, Aaron, but I imagine that there's
Speaker 3: work being done on geographical variants or subspecies or whatever.
Speaker 2: Yeah, there's very very cool work being done on the
Speaker 2: molecular epidemiology of giardia.
Speaker 1: It's very cool.
Speaker 3: A couple of questions real quick, because you mentioned wildlife
Speaker 3: and livestock, What do we know about the prevalence in
Speaker 3: I know that this is a huge question, but like
Speaker 3: in general, is there much known about the prevalence of
Speaker 3: giardia in wildlife or different wildlife species? Everyone calls it
Speaker 3: beaver fever. We can't get through the episode without saying
Speaker 3: beaver fever? Yeah, and so what is the actual prevalence
Speaker 3: in beaver's And then the second question or fifteenth question,
Speaker 3: what about live stock?
Speaker 2: Yeah?
Speaker 3: Are pigs more likely than cows? Are chickens more likely
Speaker 3: than goats?
Speaker 2: Where, Aaron, you're asking all the right questions, You're one
Speaker 2: hundred percent asking all the right questions.
Speaker 1: I don't have the answers to all of them.
Speaker 2: Aaron, Livestock are affected at very high rates in general,
Speaker 2: and a lot of times, if you end up with one,
Speaker 2: for example, infected cow on a farm, then you're likely
Speaker 2: to have every single cow infected on that farm.
Speaker 1: So that's livestock.
Speaker 2: It's very very common among livestock. How common it is
Speaker 2: among wildlife totally varies into depends on what type of
Speaker 2: wildlife you're talking about and where they are. I mean,
Speaker 2: because again, this is a disease. This is a parasite
Speaker 2: that's found across the entire globe.
Speaker 3: Are there any species that don't get infected when exposed?
Speaker 2: Oh?
Speaker 1: Good question? Don't know? Okay, yeah, I don't have no idea.
Speaker 2: The other thing is we have no we don't have
Speaker 2: a good grasp on whether it's distinct species or subspecies
Speaker 2: of Girardi, a parasite being transmitted among wildlife and livestock
Speaker 2: and humans. I know, I keep saying it with two arts,
Speaker 2: Just leave it.
Speaker 3: I just keep thinking Girardi above.
Speaker 1: Every time I see your face, I know I've said
Speaker 1: it wrong.
Speaker 3: I'm tried to poker face this, but I can't.
Speaker 1: You're failing at a poker face.
Speaker 2: But there is a lot of molecular epidemiology work being
Speaker 2: done to try and figure this out, because who has
Speaker 2: classified this as a zoonotic pathogen, which means that you
Speaker 2: would expect that most of the transmission happens in a
Speaker 2: zoonotic pathogen between wildlife or other animals and humans. But
Speaker 2: in many cases that doesn't seem to be the case,
Speaker 2: and it might even be more likely that humans are
Speaker 2: actually infecting wildlife at just as high, if not higher
Speaker 2: rates than wildlife end up infecting humans.
Speaker 3: Mm hmmmmmm mm hmm.
Speaker 1: It's so cool.
Speaker 2: So while there's no doubt that giardia can be a
Speaker 2: zoonotic disease, we don't know how frequently it's actually zoonotic
Speaker 2: versus just a human disease that circulates among human populations.
Speaker 3: Also, quick question, what's the opposite of zoonotic?
Speaker 2: Is it anth anthroponotic? Anthroponotic?
Speaker 3: Fact checked me, I'm doing it, thank you anthroponosis, Yeah,
Speaker 3: anthroponoses Yep, there we go.
Speaker 1: Perfect.
Speaker 2: So cool, we don't know fully. I will post a
Speaker 2: link on our website to two very great reviews, one
Speaker 2: from two thousand and four another from twenty eleven that
Speaker 2: dive really deeply into this Don we don't have time
Speaker 2: in this episode to dive into all the different subgroups
Speaker 2: and subspecies and whether there should be multiple species of
Speaker 2: Girardia Giardia duat analyis or not, et cetera, et cetera.
Speaker 2: But what I do want to say is it seems
Speaker 2: as though at this point a lot of the transmission
Speaker 2: and a lot of the outbreaks that we see in
Speaker 2: humans happen between humans human to human transmission. So while
Speaker 2: things like drinking surface groundwater from a mountain stream is
Speaker 2: absolutely a risk factor forgetting grdiasis, it's not like we
Speaker 2: can just blame it on the beavers.
Speaker 1: Don't blame it on the beavers.
Speaker 2: It's equally possible that that the water has been contaminated
Speaker 2: by humans or domestic or livestock animals.
Speaker 1: Isn't that just so cool?
Speaker 3: That's very interesting.
Speaker 2: It makes so much more sense to me knowing that
Speaker 2: it's been so recent that people have even been recognizing
Speaker 2: this as a disease, because I was like, how do
Speaker 2: we know so little about the molecular epidemiology and like
Speaker 2: the distribution of this disease among wildlife and livestock and
Speaker 2: what species or subspecies are affecting humans versus wildlife, Like,
Speaker 2: it's bananas to me that we know so little, but
Speaker 2: there's very very cool research being done on it.
Speaker 3: Yeah.
Speaker 1: Good.
Speaker 2: The other big field of research right now is in vaccines.
Speaker 2: So there does exist already a licensed vaccine for dogs
Speaker 2: and cats, but it's not great. It doesn't work very well.
Speaker 2: As it turns out. It decreases the shedding of cysts
Speaker 2: in the stool of dogs, but it doesn't actually prevent
Speaker 2: infection or reduce symptoms of the disease. So it's kind
Speaker 2: of if you're talking about giving it to your pet dog,
Speaker 2: it doesn't seem to actually be that helpful.
Speaker 3: Hmm.
Speaker 2: Okay, but that just means that there's room for new research.
Speaker 2: I found a very cool study that was published in
Speaker 2: twenty sixteen. It was a massive, massive study. Sometimes I
Speaker 2: look at these and I'm like, good lord, you put
Speaker 2: like six years worth of work into one paper. Whoof Yeah,
Speaker 2: but it was nature, so you know.
Speaker 3: Yeah.
Speaker 2: So this group developed a vaccine, a component vaccine that
Speaker 2: was actually a vaccine against the human genotypes that are
Speaker 2: more common among humans than dogs and cats. Okay, And
Speaker 2: it was a component vaccine, so just the surface proteins,
Speaker 2: not an entire killed parasite, which is what the vaccine
Speaker 2: that's for dogs is today. So in this paper, they
Speaker 2: showed that this vaccine could both stimulate an immune response
Speaker 2: in puppies and kittens, so actually stimulated their immune system
Speaker 2: to develop antibodies, that this immune response was actually protective
Speaker 2: against infection with Giardia. So they exposed the puppies and
Speaker 2: kittens to gerardia, and then they vaccinated dogs and cats
Speaker 2: in a community and they found that it protected the
Speaker 2: puppies and kittens, the dogs and cats in that community
Speaker 2: from infection. So over time, infection was less in the
Speaker 2: dogs and cats that were vaccinated. In fact, none of
Speaker 2: the dogs and cats that were vaccinated ended up getting infected.
Speaker 1: After two years. WHOA, that's great.
Speaker 3: Yeah.
Speaker 2: On top of that, they tested children in that community,
Speaker 2: and infection in children in that area decreased over that
Speaker 2: time period as well. So in this paper they were
Speaker 2: suggesting that vaccinating dogs and cats against this specific species
Speaker 2: or subspecies, this specific genotype of Gerardia could actually help
Speaker 2: potentially prevent the spread of disease in humans.
Speaker 1: Even huh.
Speaker 2: Based on a lot of the other molecular epidemiology studies,
Speaker 2: it seems like that's very context dependent because in a
Speaker 2: lot of communities there's actually very little overlap between the
Speaker 2: genotypes of Giardia that circulate among dogs and those that
Speaker 2: circulate among humans. So it would really depend on so
Speaker 2: where they did this study in Argentina that happened to
Speaker 2: be true, but in another community it very well may
Speaker 2: not be. But it's still very cool, huh So, and
Speaker 2: again I'll post.
Speaker 1: The link to that study as well.
Speaker 3: Of course, So about the widespread prevalence of giardia and
Speaker 3: how problematic it is for nutrition and just overall health,
Speaker 3: what are the kind of secondary outcomes associated and like
Speaker 3: in terms of dalis or anything else like that.
Speaker 1: So I couldn't find.
Speaker 2: Numbers on that. A lot of the studies on Gerardia
Speaker 2: that look more at that Giardia becomes more important in cases.
Speaker 1: Of co infection.
Speaker 2: So when you have areas where you have really high
Speaker 2: rates of coinfection with Gerardia and things like hookworm or
Speaker 2: other intestinal worms, that's when you see worse outcomes for
Speaker 2: people in terms of nutrition and malnutrition and things like that.
Speaker 2: But just looking at Gerardia alone, there's not a ton
Speaker 2: of great EPI data that I that I was able
Speaker 2: to find.
Speaker 3: Okay, interesting.
Speaker 2: Yeah, yeah, so yeah, that's pretty much jarediasis.
Speaker 3: And Lasha how about it?
Speaker 1: How about it? Don't swim in a pool if you
Speaker 1: have diarrhea?
Speaker 3: Please.
Speaker 1: Yeah, that's what I gleaned from all.
Speaker 3: I have one more question for you. Okay, how scared
Speaker 3: should we be of Jaredia?
Speaker 2: I think we should be scared that we know so
Speaker 2: little about it?
Speaker 3: God, Okay, maybe it's other h Pylori.
Speaker 1: Yeah, it could be.
Speaker 2: It really could be, like who knows what this thing
Speaker 2: has been doing in our guts for so long?
Speaker 3: Clearly causing lactose intolerance and all kinds of people.
Speaker 1: And all kinds of things, ibs et cetera. Cool. That
Speaker 1: was fun sources, fun, okay, sources.
Speaker 3: I'm gonna mention a couple of books that I read.
Speaker 3: One is called Drinking Water, a history by James Salzman,
Speaker 3: and the other one is called I of the Beholder
Speaker 3: Johannes vermir Anthony von Lavenhook and the Reinvention of Seeing.
Speaker 3: But that's by Laura Snyder. So if you just google
Speaker 3: Ie of the Beholder, you're going to get a lot
Speaker 3: of like bodice ripping romance novels. You have to put
Speaker 3: in laven Hook or Vermiir. But this book was really
Speaker 3: interesting because it dove into both art history and the
Speaker 3: history of microscopes, and it was just a really sort
Speaker 3: of big picture history book. I really enjoyed it.
Speaker 2: So, Melissa allman, if you're listening, you should read it.
Speaker 3: You'll love this, Melissa. And then I've read some articles
Speaker 3: that I'll post the links to on our website.
Speaker 2: Yep. As always, we'll post the links to all of
Speaker 2: our sources on our website. This podcast will Kill You
Speaker 2: dot com. You can find our sources from this and
Speaker 2: all of our episodes.
Speaker 3: Thank you all for listening. Yeah, I really appreciate it.
Speaker 2: Thank you also to Bloodmobile for the music in this
Speaker 2: episode and all of our episodes.
Speaker 3: And stay tuned because you are going to get a
Speaker 3: wonderful song that if you listen to the Hookworm episode
Speaker 3: you've heard before, Parasite Love Song is gonna play us out.
Speaker 3: It's the best. Thank you so much to Merrimac Valley
Speaker 3: Girl for letting us play it again. And you can
Speaker 3: find her website at Merrimackvalleygirl dot com and she also
Speaker 3: has an Instagram m E r amec Valley Girl. All Right,
Speaker 3: until next time, Wash your hands, you filthy animals.
Speaker 4: I cannot live without you, naughty, even for a day.
Speaker 4: Please don't try to push me out. Please just let
Speaker 4: me stay. It's a miracle I've found you. Introductions were
Speaker 4: not forced. They'd brought us together. Let nature take her course.
Speaker 4: You tried to avoid me, but my instincts were too good.
Speaker 4: Your defense is now arising, but I knew that they would.
Speaker 4: I never want to hurt you.
Speaker 3: I don't want to make you.
Speaker 4: Please do you understand me?
Speaker 1: Do you know that I have needs?
Speaker 4: Have you ever felt so wanted? I may be a fluke,
Speaker 4: our support may not be mutual, but please do not
Speaker 4: rebuke your giver. I'm a taker, but relations can evolve.
Speaker 4: I'll adapt to stay with you. Our problems can be solved.
Speaker 4: Oh what do I love about you? You're such a
Speaker 4: lovely host, your beautiful and rich inside where.
Speaker 1: It counts the most.
Speaker 4: I promise I won't cheat on you.
Speaker 1: Please just let me stay.
Speaker 4: I cannot live without you, not even for a day.
Speaker 3: I want you out your magne sick.
Speaker 4: I want you out your magne sick. I want you
Speaker 4: out your magnie sick. You're lousy and your magnie sick.
Speaker 2: Also I just want to say you are my mother
Speaker 2: because you managed to fit in art history and microscope
Speaker 2: history in like the same sentence.
Speaker 3: Listen, I read a great book. I'll shout it out
Speaker 3: at the end. Okay, I'll say, Melissa, you should listen
Speaker 3: to this, or you should read this.
Speaker 2: She'll be like Aaron, I've already read it, just kidding.
Speaker 3: Probs, we're friends on Goodreads, so maybe she's already seen
Speaker 3: that I've read it, and then she'll add it to her
Speaker 3: good Reads.
Speaker 1: I love it.