Speaker 1: Professor Yokogawa casually spoke to me jokingly, saying, Yoshino, as
Speaker 1: Tenia solium is present in your home, Okinawa, how about
Speaker 1: doing experimental infection for your PhD study. Of course, Yokogawa
Speaker 1: and I knew epilepsy and neurocysta sercosis could be caused
Speaker 1: by accidental ingestion of eggs of this parasite. At first,
Speaker 1: I was very nervous about accidental neurosiste sercosis in my brain,
Speaker 1: et cetera. However, it was an exceptionally big chance for
Speaker 1: me to do an experimental infection. Even if I had
Speaker 1: a serious health problem or sudden death, My data might
Speaker 1: contribute to this topic that nobody has done and therefore
Speaker 1: be highly informative for future advances in parasitology. Then I
Speaker 1: felt some power inside of my body which pushed me
Speaker 1: to do it right then, and I swallowed three sister serki.
Speaker 1: When I came back to my home in the evening,
Speaker 1: I told this mission to my wife. She was very surprised,
Speaker 1: but tried to understand my hard academic life and took
Speaker 1: more care of my health as my purpose was observing
Speaker 1: gravid proglotids and feces. I stopped using toilets anywhere, but
Speaker 1: kept a portable toilet and chopsticks for looking for gravid
Speaker 1: proglottids and collected them all every day for three hundred
Speaker 1: seventy one days.
Speaker 2: I love this first hand account.
Speaker 1: I love it.
Speaker 2: I love it so much erin it's okay, let me
Speaker 2: tell you where it's from, because I stumbled across this
Speaker 2: and it just proved to be so much deeper that
Speaker 2: I that I had expected. Okay, so that is from
Speaker 2: ETO at All twenty twenty. The paper is titled Kozen
Speaker 2: Yoshino's Experimental Infections with Tenia Solium Tapeworms an experiment never
Speaker 2: to be repeated. And this paper goes into this experiment
Speaker 2: that Yoshino did back in the nineteen thirties I believe,
Speaker 2: or late nineteen twenties, with this experimental infection of tapeworm
Speaker 2: and then the resulting papers that Yoshino published on the subject.
Speaker 2: And it's a really interesting paper. But yeah, I just
Speaker 2: I loved that description of like this, well, to do
Speaker 2: this and even if I die, the data will be useful,
Speaker 2: like right.
Speaker 1: The description of feeling like a little power and then
Speaker 1: just like doing it, I love that.
Speaker 2: Yeah. Yeah, ah well, Hi, I'm Aaron Welsh and I'm
Speaker 2: Erin Almann Updike and this is this podcast will Kill You.
Speaker 1: And today we're talking about tapeworms.
Speaker 2: Tapeworms.
Speaker 1: Yeah, yeah, it's gonna be fun to see how this
Speaker 1: one shakes out. Erin, I have no idea what you're
Speaker 1: going to talk about.
Speaker 2: I know nothing about how tapeworm biology works, and so
Speaker 2: it's gonna be interesting. But I'm excited for it.
Speaker 1: It's gonna be fun.
Speaker 2: And I'm also excited because guess what time it is.
Speaker 1: It's quarantine any time it is.
Speaker 2: What are we drinking this week?
Speaker 1: We're drinking Brave New Worm.
Speaker 2: I feel like in one of our Wormy Parasite episodes
Speaker 2: we talked about how we're just gonna do like worm
Speaker 2: worm pun worm world puns. Yes, Lydia point on And
Speaker 2: I actually really like the name for this, and I
Speaker 2: think it fits tapeworms because Tenia tapeworms the ones that
Speaker 2: infect humans part of their host switching abilities and being
Speaker 2: able to find a new host. I feel like it's
Speaker 2: encapsulated in the name Brave New Worm. I love it.
Speaker 1: I love it. How poetic Karin.
Speaker 2: Yeah, and in Brave newworm is gin lemon juice, Earl
Speaker 2: Gray tea, a little bit of honey, simple syrup, and
Speaker 2: then garnish with a piece of lemon that you cut
Speaker 2: in the shape of.
Speaker 1: A worm, like a really long tapeworm. Preferentially, Yeah, we'll
Speaker 1: show pictures and we'll post the full recipe for that
Speaker 1: quarantini as well as our non alcoholic plusy Brita on
Speaker 1: our website This podcast will kill You dot com and
Speaker 1: all of our social media channels.
Speaker 2: And on our website This podcast will kill You dot Com.
Speaker 2: I've got my post it note here, which will tell
Speaker 2: me that you can find the sources for this episode
Speaker 2: and all of our episodes transcripts, recipes, bookshop dot Org,
Speaker 2: affiliate account, Goodreads list, music by Bloodmobile, merchandise, Patreon, and
Speaker 2: alcohol free episodes.
Speaker 1: I want everyone to know that Aaron was genuinely looking
Speaker 1: at a little post it note in her eyes kept
Speaker 1: flicking back and forth to read the post it note,
Speaker 1: and I really enjoyed it.
Speaker 2: You know what, There's only so much I can fit
Speaker 2: into my brain, unlike a given evening that we're recording,
Speaker 2: and post it's really helped me.
Speaker 1: Speaking of post its, shall we refer to our notes.
Speaker 2: And great segue. Thanks.
Speaker 1: Thanks, I try and dive into this episode.
Speaker 2: Let's do it. I'm excited right.
Speaker 1: After this break. There are quite a few different species
Speaker 1: of tapeworm. As a general rule, there's a lot, but
Speaker 1: there are a few different species that can infect humans.
Speaker 1: Those are which we're going to be focusing on today.
Speaker 1: Some of these species infect humans because we are evolutionarily
Speaker 1: the definitive or final host for adult worms, and some
Speaker 1: of which infect us incidentally, either as adult worms or
Speaker 1: as the intermediate stages, which I'll get into in just
Speaker 1: a minute. Plan for this biology section, we'll see how
Speaker 1: this turns out, was to just talk very generally about
Speaker 1: tapeworms as a group, because I think the broad strokes
Speaker 1: of their life cycles are not only so fascinating, but
Speaker 1: we can also cover a lot of ground by keeping
Speaker 1: things pretty general. And then I'll focus on a couple
Speaker 1: of species of tapeworm in particular that for humans stand
Speaker 1: a little bit apart.
Speaker 2: That makes sense, Let's do it.
Speaker 1: So tapeworms are fascinating, almost adorable little creatures. Sure, some
Speaker 1: of the scanning electron micrographs are like kind of cute, Okay,
Speaker 1: Tapeworms are flatworms in the phylum platy Helmentes in the
Speaker 1: class Cestoda, so different than the other flatworm friends that
Speaker 1: we've talked about on this podcast, the flukes which are
Speaker 1: the causative agent of schistosimiasis, and tapeworms are an entirely
Speaker 1: parasitic class of animals, which is awesome in and of itself,
Speaker 1: and in general they have fairly complex life cycles, much
Speaker 1: like the flukes that cause schistosimiasis. So let's go over
Speaker 1: it first. We'll start with the eggs, which are passed
Speaker 1: in feces, so in poop, the eggs enter the environment
Speaker 1: and then have to first be ingested by an intermediate host. Now,
Speaker 1: this intermediate host can be anything from a copapod in
Speaker 1: the case of something like a fish tapeworm, to a
Speaker 1: pig or a cow in the case of various species
Speaker 1: of human tapeworms, or a sheep or a rat in
Speaker 1: the case of like a dog tapeworm, et cetera, et cetera. Right,
Speaker 1: and in these intermediate hosts, in general, the eggs leave
Speaker 1: the guts of those animals and mature into a larval
Speaker 1: or immature stage which insists, so they tend to form
Speaker 1: these little cysts in various organs in the body, like
Speaker 1: the liver or the muscle or whatever, and then they
Speaker 1: hang out in these intermediate hosts, often not causing too
Speaker 1: much harm, although sometimes they might hasten capture by a
Speaker 1: carnivore in some way, like maybe making a rat easier
Speaker 1: to catch by a dog, for example. And then these
Speaker 1: cyst stages have to be ingested by their final or
Speaker 1: definitive host, and once they are they exist in the
Speaker 1: guts of that definitive host. They mature in vertebrate guts
Speaker 1: into adult tapeworms. Gennero.
Speaker 2: So can we talk a little bit about the cyst sure?
Speaker 1: What would you like to talk about?
Speaker 2: What is it made of?
Speaker 1: Like?
Speaker 2: Is the growth of the tapeworm just completely arrested? Like?
Speaker 1: Is it? Great question? It depends on the species, but
Speaker 1: in general no. So the cysts are little little baby tapeworms.
Speaker 1: They have a little head and a little skull x
Speaker 1: that's what the head is called. I'll talk about it
Speaker 1: in a second. And then they have like a part
Speaker 1: of a little body, and then they have just a
Speaker 1: little structure around them, which is what entraps itself in
Speaker 1: say the muscle or the liver of the intermediate host,
Speaker 1: and it.
Speaker 2: Does that to evade the immune system exactly.
Speaker 1: So these cysts tend to be very good at evading,
Speaker 1: especially vertebrate hosts immune responses. They just can hang out
Speaker 1: there for in some cases quite some time, like a
Speaker 1: number of months or even years, just waiting to be ingested.
Speaker 2: And then another question about these cysts, I just I'm
Speaker 2: so fascinated by yeah, by these cysts. So if the
Speaker 2: intermediate host dies with this, with these cysts, you know,
Speaker 2: throughout their muscle, how long in the environment would they last?
Speaker 2: Would there be scavengers that could come in? Like, how
Speaker 2: would that work?
Speaker 1: That is a very good question. I don't fully know
Speaker 1: the answer, and I expect that it varies quite a
Speaker 1: lot depending on the species. But in general, this is
Speaker 1: something that usually needs to be ingested while it's alive,
Speaker 1: So it would be a lot of times it's carnivores
Speaker 1: that are the kind of definitive host of these creatures,
Speaker 1: or in the case of like fish tapeworms, if fish
Speaker 1: are ingesting copa pods and things whole.
Speaker 2: Right, Okay, yeah.
Speaker 1: I want to talk for a little bit about the
Speaker 1: adult tapeworms. Because they're fascinating. So tapeworms will post a
Speaker 1: lot of pictures of them on our Instagram, So if
Speaker 1: you don't follow us, you should, because again they're very cool.
Speaker 1: They have a head which has no eyes, no light
Speaker 1: sensing organs, no mouth. Their head is often called a skulex,
Speaker 1: and it's just a set of hooks and or suckers
Speaker 1: that they use to anchor on to the gut wall
Speaker 1: of their vertebrate host and then attached to this little
Speaker 1: head or skulllex. They have a skinny, little neck and
Speaker 1: from this neck they make their body, and their body
Speaker 1: is formed of a bunch of segments that are called proglottids.
Speaker 1: So this worm, what it does is it attaches by
Speaker 1: the hooks on its head to our gut wall and
Speaker 1: absorbs its nutrients through its body by just diffusion across
Speaker 1: its body. It doesn't have a mouth, what exactly, It
Speaker 1: has no mouth, just as our gut contents flow past.
Speaker 1: They absorb whatever they need through their tegument that's their
Speaker 1: version of skin, and their neck is constantly producing more
Speaker 1: and more of these proglotted segments from like you can
Speaker 1: think of it as from like the top of the
Speaker 1: neck and then they displace the older proglottids down and
Speaker 1: down and down right. And so this tail of the
Speaker 1: body of this worm is just growing longer and longer
Speaker 1: and longer, reaching toward our anus right as it grows
Speaker 1: along our gut tract, adding more and more segments. Now
Speaker 1: these proglotted segments. Each one of these segments has an
Speaker 1: entire reproductive tract, both like testes that make sperm and
Speaker 1: ovaries that are making eggs, and they self fertilize. It's amazing.
Speaker 2: That is incredible, I know.
Speaker 1: And as this worm matures and becomes longer and longer,
Speaker 1: adding these segments, the mature final segments that are fully fertilized,
Speaker 1: chalk full of eggs break off and are passed through
Speaker 1: the feces of the host and enter the environment. Chalk
Speaker 1: full of hundreds, if not thousands of eggs.
Speaker 2: Interesting, So it's not a lot of eggs in your stool,
Speaker 2: it's this whole blotted for vlotted. Yeah, oh wow, I know,
Speaker 2: it's great, right, I My mind is just blown, I know,
Speaker 2: and I.
Speaker 1: Know that that was a lot. So I'm going to
Speaker 1: just do a very brief recap of the whole life
Speaker 1: cycle of tapeworms. Ready, yeah, egg intermediate host eats the
Speaker 1: egg cysts in various tissues. Definitive host eats those tissues.
Speaker 1: Adult worm in the gut poops out eggs. That's all
Speaker 1: tapeworms in general.
Speaker 2: A circle of life, circle of life. Okay, so this
Speaker 2: probably varies a lot from species to species. But how
Speaker 2: long do some of these eggs stay in the environment
Speaker 2: or can exist in the environment.
Speaker 1: Great question. I don't have an exact number, but they
Speaker 1: are quite environmentally tolerant in gener so they can like
Speaker 1: dry out and still be potentially infectious, so they can
Speaker 1: live for a decent amount of time. Wow. Yeah, Now
Speaker 1: many tapeworm species really. I think some of the papers
Speaker 1: I read said that probably every vertebrate has at least
Speaker 1: one species of tapeworm that infects it. So there are
Speaker 1: tons and tons of tapeworm species, and that was a
Speaker 1: very general overview. We're going to focus today on just
Speaker 1: a few of these tapeworm species that infect humans. Tenia solium,
Speaker 1: Tenia saginata, and Tenia asiatica, which is very closely related
Speaker 1: to Tenia saganata. These three are the main species of
Speaker 1: tapeworm that have humans us as a major definitive host.
Speaker 1: Tenius saganata is commonly known as the beef tapeworm because
Speaker 1: its intermediate host is a cow and we get infected
Speaker 1: from undercooked cow meat. Tenius solium is commonly known as
Speaker 1: the pork tapeworm because its intermediate host is a pig
Speaker 1: and we get it from eating undercooked pork. Teenie asiatica
Speaker 1: also tends to infect pigs. Now, there are a few
Speaker 1: other species that are very important for humans as well,
Speaker 1: like Diphilobothrium latam at all. There are so many different
Speaker 1: species of Diphilobothrium. These are the fish tapeworm. These also
Speaker 1: can use humans as a definitive host, but they're not
Speaker 1: very species specific, so they can grow to adulthood in
Speaker 1: various other mammals and birds as well.
Speaker 2: Okay, question about that one. Actually, yeah, so you said
Speaker 2: that in that genus that I'm not going to attempt
Speaker 2: to say die Philobothrium. You're doing great, thanks, But the
Speaker 2: fish tapeworms fish are the definitive hosts, and copopods are
Speaker 2: often the intermediate hosts.
Speaker 1: Great question. They often have two intermediate hosts ahah have
Speaker 1: an even more complex life cycle, first little copapods and
Speaker 1: then fish, and then either a bigger fish, or mammals
Speaker 1: or birds a lot of times mammals or birds.
Speaker 2: Cool cool, got it, Yeah, great.
Speaker 1: Questionnairein so, let's talk about the symptoms when you get
Speaker 1: infected with an adult tapeworm. The thing about for humans,
Speaker 1: at least almost all these species of tapeworm, whichever of
Speaker 1: those four major groups we're talking about, is that these
Speaker 1: species that are well adapted to humans, when they infect
Speaker 1: us the way that they're supposed to as adult tapeworms
Speaker 1: in our guts, they really don't do all that much
Speaker 1: to us. That is, they absorb some of our food.
Speaker 1: They can cause abdominal pain, maybe some cramping, some diarrhea.
Speaker 1: If the worm burden got to be really high, then
Speaker 1: they could potentially cause a bit more of a symptomatic infection,
Speaker 1: but it still isn't even on the scale of say
Speaker 1: something like hookworm that we've covered in the past, because
Speaker 1: they're not burrowing into our gut wall. They're just hanging
Speaker 1: on right, and they're not sucking our blood. They're just
Speaker 1: borrowing some of our food as it passes through our
Speaker 1: small intestine before we get a chance to absorb it. Okay,
Speaker 1: Fish tapeworms have been associated with some anemia due to
Speaker 1: pour vitamin B twelve absorption because these worms attach in
Speaker 1: our small intestine and that's where we absorb vitamin B twelve. Interesting, Yeah,
Speaker 1: but even that is fairly rare, okay, And I couldn't
Speaker 1: find very great data on this, but I don't think
Speaker 1: in general, worm burdens with tapeworm tend to be quite
Speaker 1: as high as they can get with like hookworm anyways.
Speaker 1: But the point is that, in a similar way that
Speaker 1: we actually saw with schistosimiasis, the severity of tapeworm infection
Speaker 1: comes not when tapeworms are acting the way that they're
Speaker 1: supposed to, but it's when they start acting a way
Speaker 1: that they're not supposed to. That is when we as
Speaker 1: humans get infected with the wrong life stage of the tapeworm.
Speaker 1: So when instead of being the definitive host, we become
Speaker 1: the intermediate host, that is when problems arise. And it
Speaker 1: turns out that this can happen with a few different
Speaker 1: species of tapeworm huh. The pork tapeworm which I've already mentioned,
Speaker 1: Tenea solium, and two species of dog or canine tapeworm,
Speaker 1: A Chinococcus granulosis and A Chinococcus multilocularis interesting. Yeah, it
Speaker 1: gets so much more interesting. So first, let's talk about
Speaker 1: how this actually happens. So, humans get infected with adult
Speaker 1: tapeworms by eating undercooked meat of beef or pork or
Speaker 1: fish that is filled with cysts. Right, So if instead
Speaker 1: of eating undercooked meat that has cysts in it and
Speaker 1: getting infected with an adult tapeworm, if we instead come
Speaker 1: into contact with the eggs of these tapeworms, that is,
Speaker 1: if we ingest anything contaminated with human poop or with
Speaker 1: dog poop, then we become the sheep or the pigs,
Speaker 1: and instead of an adult tapeworm in our gut, these
Speaker 1: eggs hatch in our stomach, become those adorable little embryos
Speaker 1: and invade through our gut walls, travel through our bloodstream
Speaker 1: to our tissues, and insist themselves with the hope of
Speaker 1: eventually being eaten.
Speaker 2: Does it ever happen where if you have an adult
Speaker 2: tapeworm infection and they're making those eggs, and they're making
Speaker 2: that little eggsac thing that that breaks open and you
Speaker 2: get insistement that way.
Speaker 1: Oh do you mean auto infection?
Speaker 2: Oh what a great question.
Speaker 1: Yes, it absolutely can happen. Okay, that kind of is
Speaker 1: what in that first hand account when the author ate
Speaker 1: SISTA SIRTC guy, that is the intermediate stage. So they
Speaker 1: ate the intermediate stage in order to grow the adult tapeworm.
Speaker 1: But what they were worried about is accidentally becoming exposed
Speaker 1: to the eggs that they were pooping out.
Speaker 2: Right, right, And so when someone has these cysts in
Speaker 2: their tissues, is it more likely that they got it
Speaker 2: from ingesting eggs from another source or from this auto infection?
Speaker 1: Great question, I think in general, from any other source.
Speaker 1: One of the papers that I read said that about
Speaker 1: twenty five percent of people with neurocysta circosis, which I'll
Speaker 1: talk about that in a second, but basically with these
Speaker 1: cysts either had in the past or currently had a tapeworm. Okay,
Speaker 1: so that's a fairly low percentage, But that was just
Speaker 1: one paper. I think we don't have a great handle
Speaker 1: on how much auto infection happens. Okay, so we talk
Speaker 1: about why these cysts become a problem, and you probably
Speaker 1: already know why. It's because they can insist almost anywhere.
Speaker 1: So in the case of Tinia solium, the disease that
Speaker 1: results from infection with this immature life stage is called
Speaker 1: cistus orcosis, and the symptoms of cistus orcosis can really
Speaker 1: vary because these embryos are traveling via our bloodstream and
Speaker 1: just they're finding their way anywhere that our blood vessels go,
Speaker 1: which is really anywhere. And you can find them insisted
Speaker 1: in muscle tissue, where most of the time they're asymptomatic.
Speaker 1: You can also find them in subcutaneous tissue like underneath
Speaker 1: the skin. Which what's really interesting is that this tends
Speaker 1: to only happen from infections happening in Asia rather than
Speaker 1: in Latin America or Africa, and at least from what
Speaker 1: I can tell, this likely has to do with the
Speaker 1: genetic differences in the population of Tinia solium in these
Speaker 1: different areas rather than any human susceptibilities.
Speaker 2: Okay, quick question, how big are the cysts?
Speaker 1: Great question? Usually for tenius olium one to two centimeters
Speaker 1: or so.
Speaker 2: Oh that's still bigger than I thought.
Speaker 1: Yeah, not huge. Just wait, and these cysts tend to
Speaker 1: be present for just a few months to years, but
Speaker 1: eventually they do gradually disappear as the embryo dies, and
Speaker 1: then our body recognizes it and kind of just takes
Speaker 1: care of that cyst.
Speaker 2: It's just tired of waiting around for you to be
Speaker 2: eaten by a.
Speaker 1: Predator, right, it just can't hack it anymore.
Speaker 2: And how long do adult tape worms live?
Speaker 1: Oh, it really varies. Let me go back to where
Speaker 1: I had that, Deah. Some parasitology textbooks will tell you
Speaker 1: like twenty to twenty five years. Oh, but I don't
Speaker 1: think that that's it's thought that that's probably an over
Speaker 1: estimation from like anecdotal cases from a long time ago.
Speaker 1: So it's probably less than five years. But it's still
Speaker 1: like they're with you for a chunk of your life, right.
Speaker 2: Yeah.
Speaker 1: These cysts from tineas solium can also end up in
Speaker 1: the eye, where in the eye you can imagine they
Speaker 1: can actually cause quite a bit of damage, like causing
Speaker 1: visual impairment because they're blocking vessels, et cetera. But the
Speaker 1: most common and most detrimental place where this particular parasite
Speaker 1: tends to insist is in the brain, right. And when
Speaker 1: it insists in the brain, it's called neurocystus orcosis brain
Speaker 1: sisters orcosis, And what happens in the brain is very
Speaker 1: similar to what happens anywhere else. These embryos make their home,
Speaker 1: they form these one to two centimeter cysts. They usually
Speaker 1: don't get much bigger than that, although they can. They
Speaker 1: hang out there for a number of months or years,
Speaker 1: and then eventually they degener our immune system wakes up
Speaker 1: and kind of notices these cysts for the first time
Speaker 1: and in helping with that degeneration causes inflammation. So neurosystus
Speaker 1: orcosis can end up causing, as you might imagine, any
Speaker 1: range of symptoms in your brain, depending on how many
Speaker 1: cysts you have, because if you're exposed to tapeworms, remember
Speaker 1: these proglottids are filled with hundreds, if not thousands of eggs,
Speaker 1: so you could potentially be exposed to quite a large number.
Speaker 1: It also depends on if these cysts are growing, because
Speaker 1: sometimes they do get a bit larger than one to
Speaker 1: two centimeters, and if they happen to be in the
Speaker 1: wrong part of the brain, that can cause blockage of
Speaker 1: the cerebrospinal fluid flowing in the brain, which can increase
Speaker 1: the pressure in your brain. But more commonly it's the
Speaker 1: end stages this inflammation, as our body is actually try
Speaker 1: trying to get rid of this cyst that causes symptoms
Speaker 1: like headaches, like mental status changes, or like very commonly epilepsy. Right,
Speaker 1: And it turns out that neurosys to circosis is one
Speaker 1: of the most common, if not the most common cause
Speaker 1: of infectious epilepsy in a lot of parts of the world,
Speaker 1: which I totally didn't realize until doing this episode.
Speaker 2: Yeah, can we talk worm burden or cyst burden. Do
Speaker 2: you have numbers for like the median cyst burden in
Speaker 2: someone who has, you know, neurosyst sircosis, or at what
Speaker 2: is there a threshold at which point epilepsy is common
Speaker 2: or is it really just depend on the placement of
Speaker 2: the cysts.
Speaker 1: It's a really good question. I don't have good numbers
Speaker 1: on that. Really, we don't have good numbers on that,
Speaker 1: especially because as much as we have numbers on the
Speaker 1: percentage of cases of epilepsy, for example, that are caused
Speaker 1: by neurosyste yircosis, what we don't have a good handle
Speaker 1: on is how many people with neurosystem circosis, like with
Speaker 1: the cysts in their brain, actually have any symptoms at all,
Speaker 1: much less epilepsy.
Speaker 2: That makes sense, So.
Speaker 1: The only good thing to say is that in a
Speaker 1: lot of cases, even though this sounds like it would
Speaker 1: be very extreme having cysts in your brain. It's very
Speaker 1: often asymptomatic, which is fascinating in and of itself.
Speaker 2: Yeah, is it just epilepsy, that's the main side effect.
Speaker 1: It's not just epilepsy. It can be in theory, anything
Speaker 1: that your brain can do. So it can mimic a stroke,
Speaker 1: or it could even cause a stroke. It can cause
Speaker 1: increased intracranial pressure if it's blocking the flow like I
Speaker 1: said of that cerebral spinal fluid. It can also cause
Speaker 1: massive headaches. Really, it can do almost anything. But for
Speaker 1: some reason that I couldn't get a great handle on,
Speaker 1: epilepsy is one of the most common presentations.
Speaker 2: And this neurosister circosis is it more highly associated with
Speaker 2: certain species of tapeworms more than others.
Speaker 1: So neurosis orcosis is only from Tinia solium.
Speaker 2: Okay, No, we're not. We don't have to worry about
Speaker 2: fish tapeworms.
Speaker 1: Fish tapeworms nope, and feef tapeworm Nope. It's just the
Speaker 1: pork tapeworm.
Speaker 2: Huh.
Speaker 1: Now that's not the only tapeworm that can infect us
Speaker 1: as an intermediate host, right, I already said it kind
Speaker 1: of caucus species can also infect us as an intermediate host.
Speaker 1: Now here it results in an entirely different disease. Two
Speaker 1: of them actually high DADD disease or cystic kindo caucus
Speaker 1: and alveolar caucus. So with this it's a similar idea
Speaker 1: except for some reason. The cysts of a kind of caucus,
Speaker 1: first of all, tend to infect our liver, not our brain.
Speaker 1: Why I was waiting, I was waiting so long for
Speaker 1: you to ask me why, Erin, I was waiting for
Speaker 1: you to ask me why do tenia solium go to
Speaker 1: the brain? Oh? Yeah, I don't know why, Erin.
Speaker 2: You were waiting for me to ask a question for
Speaker 2: which you don't know the answer.
Speaker 1: That's like most of our podcast.
Speaker 2: I feel like.
Speaker 1: I tried so hard to find the answer to this question,
Speaker 1: and I couldn't come up with a good one. The
Speaker 1: best one that I got was that in our brain,
Speaker 1: tenia solium is very protected by our blood brain barrier,
Speaker 1: so it's a good place with minimal immune response for
Speaker 1: it to hang out. But it kind of caucus if
Speaker 1: we get affected with the intermediate stage. As it burrows
Speaker 1: its way through our gut wall, it enters our portal circulation,
Speaker 1: which brings it straight to our liver, just like it's
Speaker 1: just a semiasis you might remember.
Speaker 2: Uh huh.
Speaker 1: Another place that it can commonly end up is in
Speaker 1: our lungs, and in rare cases it can go other
Speaker 1: places as well. I know your face is well.
Speaker 2: It's fascinating because it makes me think that the if
Speaker 2: there is tissue tropism, if that's been selected for, then
Speaker 2: does it have to do with the particular predator prey
Speaker 2: relationship that these species are a part of.
Speaker 1: Yeah, that's a very good question. But really in pigs especially,
Speaker 1: you can find cysticerca in the brains of pigs, but
Speaker 1: really it's their muscles that are chock full. Oh right,
Speaker 1: And you can also find it in the liver, and
Speaker 1: you can find in other places. Now, with a kind
Speaker 1: of caucus in the intermediate stage, normally when it's not humans,
Speaker 1: it kind of caucus does make its home in the
Speaker 1: livers of sheeps or in the livers of rodents for
Speaker 1: the other species of a kind of caucus, so that
Speaker 1: does make sense. In humans it goes to the same place.
Speaker 1: I know, it's very fascinating. I don't have a great answer,
Speaker 1: but I do want to tell you a little more
Speaker 1: about the cysts of a kind of caucus and the
Speaker 1: disease that it causes because it's totally different than tenius solium. Basically,
Speaker 1: these cysts. You asked earlier, how big do these cysts get? Yea, Now,
Speaker 1: with a kind of caucus, the answer is not one
Speaker 1: to two centimeters. The answer is that these cysts can
Speaker 1: get to be so massive that they are larger than
Speaker 1: your entire liver. Oh no, because what happens with a
Speaker 1: kind of caucus. You also asked, how active are these
Speaker 1: little cysts? Like, well, it kind of caucuses. Quite active
Speaker 1: because it in fact reproduces and makes more cysts within
Speaker 1: each cyst, and that is how it continues to grow
Speaker 1: ew like.
Speaker 2: A rat king of cysts. Yes, bide your liver exactly.
Speaker 2: So I'm guessing that there aren't many asymptomatic infections people.
Speaker 1: People tend to be asymptomatic until these cysts grow so
Speaker 1: large that they start causing things like nausea, vomiting, abdominal pain.
Speaker 1: If these cysts are in the lung, it's going to
Speaker 1: cause cough, shortness of breath, chest pain. And what's really
Speaker 1: dangerous about these is that because each cyst is full
Speaker 1: of hundreds if not thousands of tiny other cysts. If
Speaker 1: these have to be taken out surgically, it's actually very
Speaker 1: high risk because if you puncture that and you release
Speaker 1: those cysts, not only can that you know, infest you
Speaker 1: in a lot of other areas of your body. Those
Speaker 1: cysts can go on to like reinsist, but it also
Speaker 1: can just cause a massive immune response in us.
Speaker 2: And is that sort of the issue with treatment in general?
Speaker 1: Yes, great question. Treatment in general for adult tapeworms, treatment
Speaker 1: is very easy. It's like a single dose of an
Speaker 1: anti parasitic. But when it comes to neurocyst to yircosis
Speaker 1: or high data disease or a kind of caucosis, it
Speaker 1: is much more difficult to treat. Yeah, because you have
Speaker 1: to balance the inflammation that treatment is going to cause
Speaker 1: from your body kind of waking up and noticing these
Speaker 1: cysts with actually treating and getting rid of the parasite. Right,
Speaker 1: So it is a lot harder.
Speaker 2: Yeah.
Speaker 1: Yeah, that's the biology of a whole bunch of different
Speaker 1: tapeworms in very brief fascinating Yeah, I hope it wasn't
Speaker 1: too much messy now it was great, So Aaron, mm hmmm,
Speaker 1: I know nothing about like where these tape rooms came from?
Speaker 1: Or like why do we get infected with them? Like?
Speaker 1: How did we figure this out? How many people have
Speaker 1: dug through poop to get us here?
Speaker 2: That's those are some great questions I will see what
Speaker 2: I can do to answer them right after this break. Okay,
Speaker 2: the history of tapeworms. To cover the complete history of
Speaker 2: all tapeworms, we would have to go back incredibly far
Speaker 2: and incredibly wide, like hundreds of millions of years all
Speaker 2: over the globe. But we're not going to do that today.
Speaker 2: For the purposes of today's regular season episode. We're going
Speaker 2: to skip ahead to, oh, just a few million years ago,
Speaker 2: which is when the history of the tapeworms that I'm
Speaker 2: mainly going to talk about in this section, which are
Speaker 2: the three tenspecies that we already mentioned, it's when that
Speaker 2: history really begins. Before moving on to that history, though,
Speaker 2: I want to plug next week's bonus episode, because that
Speaker 2: is when we will get to spend a bit of
Speaker 2: time in the distant, way distant, far distant past, like
Speaker 2: tens or hundreds of millions of years ago. And while
Speaker 2: we may touch on the early history of tapeworms and
Speaker 2: that up episode. Most of what we're going to be
Speaker 2: talking about is poop poop.
Speaker 1: I can't wait. Oh, it's gonna be so good. Aaron.
Speaker 2: When doing the research for this episode, the one that
Speaker 2: we're recording right now, I came across a paper describing
Speaker 2: tapeworm eggs found in the fossilized pooh aka copralte I've
Speaker 2: been saying it wrong for years of a two hundred
Speaker 2: and seventy million year old shark, which is so cool.
Speaker 2: I love it.
Speaker 1: I love it so much.
Speaker 2: I do too. And this got me thinking more about
Speaker 2: copra LTEs, which if you've listened to the podcast before,
Speaker 2: you know how much we love fossilized poop.
Speaker 1: It's one of our favorite things.
Speaker 2: It is. And I was and I was thinking to myself, Well,
Speaker 2: what else can poop tell us? What else can what
Speaker 2: else can these copper lights tell us? So I reached
Speaker 2: out to one of the world's leading experts on wait
Speaker 2: for it, dinosaur copra light.
Speaker 1: I just I'm so excited.
Speaker 2: Next week, doctor Karen Schin, who was just up the
Speaker 2: road from me at the University of Colorado Boulder, will
Speaker 2: be joining me to dive deep into fossilized pooh. What
Speaker 2: we can learn from it how it becomes fossilized, and
Speaker 2: which kind of animals are most likely to have their
Speaker 2: pooh become fossilized. So mark your calendars.
Speaker 1: Which animals are most likely to have their pooh become fossilized? Right?
Speaker 2: Is it carnivores? Is it herbivores?
Speaker 1: Which is it?
Speaker 2: I did? You'll have to wait and find out because
Speaker 2: I don't know the answer right now. Okay, But like
Speaker 2: I said, for today's episode, we're going to start a
Speaker 2: while after the dinosaurs, like a long while. Aaron, you asked.
Speaker 2: One of the things you asked was where did these
Speaker 2: things come from?
Speaker 1: Oh?
Speaker 2: And I'm so excited to answer. Knowing what you know
Speaker 2: about the common human tape work, those three Teeneae species,
Speaker 2: and what their life cycle looks like and which animals
Speaker 2: it involves, when do you think humans and tapeworms most
Speaker 2: likely became acquainted with one another?
Speaker 1: My guess would be sometime when we started domesticating livestock.
Speaker 2: Great guess. That's such a good guess, because you know
Speaker 2: teny twelve thousand years ago, that is when humans started
Speaker 2: to domesticate livestock. That's when you know a lot of
Speaker 2: parasite and pathogen exchange happened. We've talked about this so
Speaker 2: many times in the podcast.
Speaker 1: Before, and I can tell by your tona that I'm wrong.
Speaker 2: You are, but but that is what people thought for
Speaker 2: a really long time. They thought, Okay, it had to
Speaker 2: have happened when people first started domesticating cows and pigs
Speaker 2: in particular, and we picked up these tapeworms, then they
Speaker 2: were the ones that brought tapeworms to the table. However,
Speaker 2: it seems that it was actually humans that first gave
Speaker 2: these worms to their livestock. What what I know, I know.
Speaker 2: Let's talk about why that revised version of events seems
Speaker 2: likely given some of the ecological, evolutionary and life cycle
Speaker 2: characteristics of these tapeworms. Like we've talked about, the genus
Speaker 2: Tenia is chock full of species, just dozens of species,
Speaker 2: and we actually know quite a bit about the life
Speaker 2: cycles of many of the species in Tenia, which is
Speaker 2: pretty awesome because it means that we are more easily
Speaker 2: able to explore evolutionary relationships and historical distribution patterns and
Speaker 2: host associations, all those sorts of things, so we can
Speaker 2: tell when a species diverged or experienced a host switching event.
Speaker 2: For example, like you talked about aaron, Tenia tapeworms have
Speaker 2: a definitive host, which is often a carnivorous or omnivorous mammal,
Speaker 2: and an intermediate host. The prey species also a mammal,
Speaker 2: and transmission primarily occurs in this predator prey interaction. And
Speaker 2: Tenie are actually unique in that they have mammals as
Speaker 2: both definitive and intermediate hosts, which I think is just
Speaker 2: a cool little tidbit.
Speaker 1: Yeah, that is cool.
Speaker 2: In the past, when we've talked about parasites, we sometimes
Speaker 2: talk about host specificity, how some parasite species are uniquely
Speaker 2: adapted to their host species, and how they can't complete
Speaker 2: their life cycle in another and maybe even the host
Speaker 2: and parasite have co evolved so tightly that you can
Speaker 2: mark host evolutionary events with parasite evolutionary events. But that
Speaker 2: does not seem to be the case for Tenia tapeworms
Speaker 2: in their carnivorous definitive hosts, who don't necessarily have these
Speaker 2: super tightly linked relationships. Rather, it seems that which were
Speaker 2: are associated with which carnivores depends on where those hosts live.
Speaker 2: And who the intermediate hosts are in the ecosystem. So
Speaker 2: you could have worms switching between unrelated hosts like hyenas
Speaker 2: and lions if they share the same ecosystem and prey species. Okay,
Speaker 2: And so the diversity of these tapeworm species is based
Speaker 2: more on ecological factors rather than on a phylogenetic or
Speaker 2: co evolutionary basis, which I think is really cool because
Speaker 2: you have to think about it in terms of ecosystems
Speaker 2: and like who are the players in that ecosystem? Right? Yeah,
Speaker 2: And these hosts switching patterns and tapeworms are relevant for
Speaker 2: today because things like climate change or land use change
Speaker 2: can lead to these ecological disruptions where a new tapeworm
Speaker 2: species could suddenly be introduced to a new ecosystem and
Speaker 2: then into a new host And we don't know what
Speaker 2: the possible conceptquences of that might be. All right, but
Speaker 2: what is the relevance for the history of tapeworms in humans?
Speaker 2: I'm getting there. Phylogenetic analyzes have shown that Tinia tapeworms
Speaker 2: and humans were well acquainted with each other long before
Speaker 2: humans were humans, which also means long before modern humans
Speaker 2: began domesticating pigs or cows, right, right, right, So how
Speaker 2: did tapeworms and humans get to know each other? About
Speaker 2: two million years ago or so, early hominids in Africa
Speaker 2: began to incorporate meat into their diet, scavenging the kills
Speaker 2: of predators in the area, such as lions or hyenas,
Speaker 2: or later hunting animals themselves, and when they began taking
Speaker 2: the odd leg from an antelope or a rib from
Speaker 2: a warthog, maybe they also found themselves eating not just meat,
Speaker 2: but also some of those tapeworm cysts.
Speaker 1: Honestly, it makes so much more like once you go
Speaker 1: through that logic, it makes so much more sense.
Speaker 2: Yeah, it's so it's so interesting because I was immediately assuming, Okay,
Speaker 2: here's going to be another classic example of agricultural revolution,
Speaker 2: and yeah, but no, it's I just find that so fascinating.
Speaker 2: I love it.
Speaker 1: It's just like once we became omnivores, boom boom, we
Speaker 1: get parasites.
Speaker 2: And over time humans stopped becoming just this incidental part
Speaker 2: of the life cycle, but the relationship grew much stronger
Speaker 2: and closer. And so when humans began domesticating livestock, it
Speaker 2: was the long infected humans that brought tapeworms to their
Speaker 2: pigs and cows. Yeah, wow, I f fun And do
Speaker 2: you want to hear some evidence in supportiveness? I always okay. So,
Speaker 2: for instance, the sister species of Tenia solium is Tenia hyenae,
Speaker 2: which infects hyenas and antelopes. What And the sister species
Speaker 2: of Tenia saganata and Tenia asiatica, which, like we mentioned
Speaker 2: our sister species with each other, is Tenia simbae, which
Speaker 2: commonly infects lions and antelopes. Oh what uh huh, it's
Speaker 2: so interesting. Genetic analyses estimate that Tenia saganata and Tenia
Speaker 2: asiatica probably diverged around zero point seven eight to one
Speaker 2: point seven to one million years ago, which is pretty
Speaker 2: close to the period when humans began switching from herbivy
Speaker 2: to omnivary or like a little bit after wow. And
Speaker 2: Tenia Solium's estimated divergence is a lot more recent, about
Speaker 2: three hundred and fifty nine thousand years ago. And an
Speaker 2: interesting side note, some researchers have suggested that Tenia solium
Speaker 2: was maintained in some human populations via cannibalism. In addition
Speaker 2: to this less sensational prey hyena association.
Speaker 1: I mean, I feel like that goes along with the
Speaker 1: fact that we can also serve as intermediate hostsoutely this parasite.
Speaker 2: Yeah yeah, So long story short, humans gave tapeworms to
Speaker 2: pigs and cows, not the other way around, and they
Speaker 2: seem to have done so on three separate occasions, so
Speaker 2: Tenius aginata and cattle and Tenia asiatica and Tenia solium
Speaker 2: and swine. But those last two tapeworm species aren't closely related,
Speaker 2: which is why it was thought to be two separate
Speaker 2: introductions in pigs.
Speaker 1: Right, which, like I know, that's just interesting in and
Speaker 1: of itself. Absolutely, yeah.
Speaker 2: And once inside these livestock species, they were there to
Speaker 2: stay and spread, especially over the long period of exploration
Speaker 2: and colonization that began in the fifteen hundreds. But that's
Speaker 2: getting a little bit head of things. So let's see
Speaker 2: what the ancients have to say about tapeworm Shall we.
Speaker 1: Shall we shall?
Speaker 2: Unlike microscopic parasites or pathogens, wormy parasites are visible, like
Speaker 2: you can see the actual worm segments in your poop,
Speaker 2: and for this reason it was probably easier for people
Speaker 2: to make that link between a disease causing organism like
Speaker 2: the tapeworm and the symptoms of infection, even long before
Speaker 2: the days of germ theory. Imagine having stomach cramps and
Speaker 2: fatigue and then pooping out segments of something that looks
Speaker 2: like a worm. It'd be hard not to say, oh,
Speaker 2: that's why I was feeling so cruddy these last few
Speaker 2: fortnites or whatever, And so unlike infections from microscopic pathogens,
Speaker 2: for instance, influenza, virus or plague, the first descriptions we
Speaker 2: often have of these paris diseases is actually of the
Speaker 2: parasites themselves, or sometimes the parasite plus symptoms, rather than
Speaker 2: the disease, which I find so interesting because I think
Speaker 2: it does change the way we think about the concept
Speaker 2: of disease versus pathogen. Yeah, I don't know, something I
Speaker 2: was just thinking about. Given their size and conspicuousness. Tapeworms,
Speaker 2: of course, make an appearance in the Evers Papyrus from
Speaker 2: around fifteen hundred BCE, and we also have tapeworm infections
Speaker 2: in the stomach and intestines of some Egyptian mummies. Aristotle
Speaker 2: in the three hundred s BCE described how some pig
Speaker 2: muscles appeared to have bladders or cysts that look like hailstones,
Speaker 2: and he also noted that adult pigs who were free
Speaker 2: roaming it tended to have the so called measled appearance,
Speaker 2: while nursing pigs did not. Pliny the Elder in the
Speaker 2: first century CE may have been the first to use
Speaker 2: the term tenia in reference to these worms, from the
Speaker 2: Latin word for flat band or ribbon and references to
Speaker 2: the worms. I mean really, they can be found all
Speaker 2: over the world in ancient texts from China, India, and
Speaker 2: Middle East, just to name a few. But the ancients
Speaker 2: didn't quite have it all figured out when it came
Speaker 2: to these parasitic infections, especially in terms of tapeworms. They
Speaker 2: may not have understood, for example, how exactly you get
Speaker 2: these parasites. Although the consumption of pork is banned in
Speaker 2: several cultures or religions which could have something to do
Speaker 2: with tapeworms, the oldest mentioned of banning pork comes from
Speaker 2: Leviticus and the Hebrew Bible from around six hundred to
Speaker 2: five hundred BCE. Have I read this on the podcast before?
Speaker 2: I can't remember. I maybe, Okay, well I'm gonna do
Speaker 2: it again and quote, and the pig, because it parts
Speaker 2: the hoof and is cloven footed but does not chew
Speaker 2: the cud is unclean to you. You shall not eat
Speaker 2: any of their flesh, and you shall not touch their carcasses.
Speaker 2: They are unclean to you. How interesting, yeah it is,
Speaker 2: And of course the consumption of pork is also forbidden
Speaker 2: in Islam. It's entirely possible that tapeworms, specifically in pigs,
Speaker 2: were responsible for the span, but there are also several
Speaker 2: other parasites that could have contributed to the unclean and
Speaker 2: I will say unfair reputation of pigs.
Speaker 1: Yeah, Plus, like you can get tapeworms from lots of
Speaker 1: other things, absolutely cows and fish.
Speaker 2: And also not all possible symptoms of tapeworm infection were
Speaker 2: recognized as being related to the parasite, such as this
Speaker 2: epilepsy that can emerge later in life as a result
Speaker 2: of neurosis to pircosis, which was described in Hippocratic texts epilepsy,
Speaker 2: but not in relation, of course, to tapeworm. Right, we
Speaker 2: haven't gotten to do a possible retrospective diagnosis of a
Speaker 2: historical figure in a while, so I'm excited to announce
Speaker 2: that a few Researchers have suggested that the epilepsy that
Speaker 2: Roman dictator Gaius Julius Caesar from one hundred to forty
Speaker 2: four BCE, that he began to experience when he was
Speaker 2: around fifty four years old, might be related to sister
Speaker 2: circosis neurosisis tercosis. Who knows, but what is clear is
Speaker 2: that people didn't really fully know how this life cycle
Speaker 2: was completed and the role of pigs versus cows versus whatever,
Speaker 2: and so there was no reason to try to control
Speaker 2: these diseases, and so the parasites just spread and spread
Speaker 2: and spread, Especially like I mentioned, as widespread travel and
Speaker 2: colonization occurred with more tapeworms in circulation and the rise
Speaker 2: of human anatomists in the fifteen hundreds and sixteen hundreds,
Speaker 2: it was really only a matter of time before people
Speaker 2: started recognizing the other primary way that tapeworms could infect
Speaker 2: you besides Intestinally they had seen the measled appearance of
Speaker 2: pig tissue had already been observed, but not so much
Speaker 2: in humans, and the first recorded cases of neurosisisircosis were
Speaker 2: described by Rummler in fifteen fifty eight and by Paniolus
Speaker 2: in sixteen fifty two, both of whom described the liquid
Speaker 2: filled vesicles that they found in the brains of their
Speaker 2: deceased patients, and not terribly long after these vesicles were
Speaker 2: shown to be parasitic, like shown to have those tiny
Speaker 2: little worms, which I think is absolutely amazing.
Speaker 1: I think it like in looking through so many pictures,
Speaker 1: like it makes so much sense that they were able
Speaker 1: to make these connections sooner, because these cysts are not
Speaker 1: just a fluid filled sack with nothing in it. It's
Speaker 1: a fluid filled sack with a tiny little tapeworm in it.
Speaker 1: And if you already know what tapeworms are and that
Speaker 1: they're in your guts, then it makes sense that they
Speaker 1: were able to make these connections.
Speaker 2: That's really interesting, Yeah, exactly. And so yeah, they pulled
Speaker 2: one out and you can see, oh, that looks like
Speaker 2: a head. Oh that looks like suckers, right, so it
Speaker 2: must be a living thing. Although the debate was kind
Speaker 2: of on for a bit as to whether these arose
Speaker 2: spontaneously in your gut or in your brain or something
Speaker 2: like that. Interesting, but in general, yeah, by the seventeen hundreds,
Speaker 2: people were trying to classify these different species, which is
Speaker 2: just so much earlier than we usually end up talking
Speaker 2: about in the podcast. Yeah, I think it's a really fun,
Speaker 2: really fun thing. By seventeen eighty to the three species
Speaker 2: of Tinia that I've mostly been talking about, Tenia solium,
Speaker 2: Tenius aganata, and Tenee asiatica, these three species were differentiated,
Speaker 2: and ten years later, in seventeen ninety two, a Peruvian
Speaker 2: physician named Hippolito Unanue was the first that we know
Speaker 2: of to record a case of someone a soldier with
Speaker 2: both an intestinal tape worm infection as well as neurosist pyircosis. Wow. Yeah,
Speaker 2: Even still, it wasn't fully recognized that the worm in
Speaker 2: someone's gut could be linked to those cysts in their
Speaker 2: brain until the eighteen hundreds. At that point, some German
Speaker 2: doctors floated the idea that the adult might also be
Speaker 2: the same species that causes those cysts. But how do
Speaker 2: you prove something like that?
Speaker 1: Yeah?
Speaker 2: Oh oh, well, if you're thinking like one of these
Speaker 2: German doctors, specifically the one by the name of Kuchenmeister,
Speaker 2: you would find yourself a quote volunteer no in his case,
Speaker 2: a few condemned prisoners, and you would feed them sausages
Speaker 2: and a noodle broth containing Tenia solium cysts from a pig.
Speaker 2: And then you just wait a few weeks for the
Speaker 2: execution date and then perform your autopsy boom results. That's
Speaker 2: exactly what Kuchenmeister did, and in the autopsies he did
Speaker 2: find quote a small Tenia that was tightly attached with
Speaker 2: its proboscis to a piece of duadenal mucosa and nine
Speaker 2: other worms. Oh there you go, wow, question answered. All
Speaker 2: you had to do was just find yourself some volunteers,
Speaker 2: and over the next few decades, the life cycle of
Speaker 2: this and other Tenius species was more fully fleshed out.
Speaker 2: And this classic TPWKY episode wouldn't be complete without an
Speaker 2: instance of self experimentation or more accurate self experimentation plus
Speaker 2: a few volunteers. This is what you heard in our
Speaker 2: first hand account. Basically, in the nineteen thirties, this researcher
Speaker 2: mentioned named Kozen Yoshino infected himself so that he could
Speaker 2: better study the life cycle of Tinia solium. I think
Speaker 2: it was actually for his dissertation wo and he published
Speaker 2: six papers from it, which was pretty pretty impressive. True commitment.
Speaker 2: He go a lot more than I published and other
Speaker 2: good news. As far as we can tell, Yoshino never
Speaker 2: developed any signs of cistisircosis, and his experiment did show
Speaker 2: us and quite a bit actually about the different stages
Speaker 2: of infection, symptoms, life cycle, and the infection rate of
Speaker 2: this parasite. Into the twentieth century, cistusircosis grew in prevalence
Speaker 2: in some areas and declined in others, especially in those
Speaker 2: places where food inspection or livestock feeding laws were enacted
Speaker 2: to try to reduce transmission of these parasites. And prevention
Speaker 2: really was key because, like we talked about, treatment can
Speaker 2: be difficult, especially for the sisters rcosis, and treatment is
Speaker 2: still it's not that great, Like the drug that seems
Speaker 2: most commonly used today wasn't developed until the nineteen seventies,
Speaker 2: and it has nearly as many terrible side effects as
Speaker 2: earlier drugs which were questionable in their efficacy. Right Still,
Speaker 2: the side effects from this drug, however horrible, aren't nearly
Speaker 2: as bad as an infection with tapeworms can be. Maybe
Speaker 2: it goes without saying after what you heard in the biology,
Speaker 2: or maybe it bears repeating, because let's talk about the
Speaker 2: tapeworm diet real quick. This last bit of history is
Speaker 2: maybe a little bit out of order, but I promise
Speaker 2: I'll bring us up to the present day at the
Speaker 2: end of it. Have you heard of the tapeworm diet?
Speaker 1: Oh? Oh yeah, oh yeah, definitely.
Speaker 2: I feel like I've heard it mentioned jokingly here and there,
Speaker 2: but I always assumed that that's exactly what it was,
Speaker 2: like a joke. Where would you even get tapeworm eggs?
Speaker 2: A tapeworm infection has to be bad for you. How
Speaker 2: do you get the worm out? It just seemed kind
Speaker 2: of ridiculous and a terrible idea through and through. But
Speaker 2: when it came time to do this episode, I wanted
Speaker 2: to dig a bit deeper just to see what was
Speaker 2: out There. Was this tapeworm diet based in anything real?
Speaker 2: Who first got the idea and how did they implement it?
Speaker 2: To answer these questions, we have to go back to
Speaker 2: the Victorian era around eighteen thirty two nineteen hundred. The
Speaker 2: predominant beauty aesthetic during this time in Europe and North
Speaker 2: America was tiny waists, transparent skin, delicate features, rosy cheeks,
Speaker 2: red lips, and so on. And this aesthetic kind of
Speaker 2: coincided with the rising prevalence of tuberculosis, which can cause
Speaker 2: someone who is infected to have many of those features
Speaker 2: because you're dying of this horrible disease. And I think
Speaker 2: we talked about the romanticization of tb in our episode.
Speaker 1: Yeah, yeah, I remember that.
Speaker 2: It also coincided with the rise of the temperance movement,
Speaker 2: which urged self restraint and a controlled diet with flavorless
Speaker 2: foods like this is kind of where Graham Crackers got
Speaker 2: their start.
Speaker 1: Oh yeah, we've talked about that on this podcast before too.
Speaker 2: We have. And the history of the thin ideal, the
Speaker 2: so called thin ideal, and the factors behind its rise
Speaker 2: is too much to cover in this one episode, but
Speaker 2: I just wanted to briefly describe how, over this period,
Speaker 2: especially during the Victorian era, body shape and size became
Speaker 2: tied to morality and the pressure to conform to these
Speaker 2: new beauty standards quote unquote, and societal expectations led people
Speaker 2: to seek ways that they could do that, anyway they
Speaker 2: could do that. Or you could also look at this
Speaker 2: as people using these manufactured expectations to make money through
Speaker 2: wacky and dangerous exercise machines. A pamphlet on the chew
Speaker 2: and spit diet or tapeworm pills. In the later decades
Speaker 2: of the eighteen hundreds, various companies advertised a mail service
Speaker 2: where they would send you a few tapeworm eggs for
Speaker 2: a nominal fee. Which is funny now that I know
Speaker 2: more about the biology, that they would send eggs, So
Speaker 2: I have.
Speaker 1: So many issues with this. Yeah, go ahead, Yeah, the
Speaker 1: idea you're saying is that someone would get an adult
Speaker 1: tapeworm to suck up some of their food so that
Speaker 1: they then lose weight. Right, that's the idea behind the
Speaker 1: tapeworm diet. Yes, yeah, so eggs is obviously not going
Speaker 1: to do that.
Speaker 2: Nope, you're just going to insist.
Speaker 1: Also, like, these are environmentally stable eggs, but you're not
Speaker 1: going to ship them across the world, like in the
Speaker 1: what year is this you're saying, seventeen hundreds, you.
Speaker 2: Know, late eighteen h undreds, early nineteen hundreds.
Speaker 1: In the eighteen and nineteen hundreds, You're not going to
Speaker 1: ship these eggs and have them survive the journey and
Speaker 1: even be infectious.
Speaker 2: No, not to mention the fact that even if somehow
Speaker 2: you could give someone tapeworms adult tape worms, that's not
Speaker 2: going to they're not going to eat enough of your
Speaker 2: life enough, right, It.
Speaker 1: Just could cause some like vitamin and mineral deficiencies.
Speaker 2: You could have diarrhea and stomach cramps, you sure could.
Speaker 2: You could have fatigue. Yeah. And so that's the thing
Speaker 2: is that if we're talking about this in the late
Speaker 2: eighteen hundreds early nineteen hundreds clinical trials, it wasn't even
Speaker 2: like a glimmer in the eye of someone who it
Speaker 2: just it wasn't even remotely a thing, first of all.
Speaker 2: Second of all, these quote unquote tapeworm eggs may have
Speaker 2: just been placebo. They might have just been empty little
Speaker 2: pill canister thingies, yeah, or.
Speaker 1: Like little little granules of rice.
Speaker 2: Sure anything. And third, I also want to point out
Speaker 2: that somehow, despite the fact that you and I both
Speaker 2: he had heard of the tapeworm diet before doing this episode,
Speaker 2: it wasn't even very popular or like a big fad,
Speaker 2: so people weren't really doing it all that much. So yeah,
Speaker 2: so it made me wonder, like, why is this still around?
Speaker 2: And the answer isn't. I don't know the answer, probably
Speaker 2: because like it does conjure up a very visceral image
Speaker 2: of a giant parasitic worm that's like eating your food,
Speaker 2: even though that's not what happens.
Speaker 1: Yeah, yeah, I mean it is what happens, and that
Speaker 1: they can get to be quite large and they do
Speaker 1: eat your food, right, but it's not like that.
Speaker 2: No, So yeah, I think that it's kind of a
Speaker 2: very interesting snippet of history that somehow has left an
Speaker 2: impact on popular culture. It has been referenced recently on
Speaker 2: reality shows, there have been news reports of people trying
Speaker 2: this out at home, which absolutely don't do, and actual
Speaker 2: super sketchy websites that claim to sell either eggs or
Speaker 2: other life stages to help you grow an adult tape room. Yeah,
Speaker 2: but I think the fact that it's still known today
Speaker 2: really says more about just how much cultural pressure there
Speaker 2: is to conform to these certain manufactured quote unquote beauty
Speaker 2: standards that intentionally ingesting a worm could ever seem like
Speaker 2: a good idea. Not to mention, it draws attention to
Speaker 2: all these predatory people and companies out there that take
Speaker 2: advantage of that. So anyway, the tapeworm diet, though a
Speaker 2: blip in the history of snake oil salesmen, still has
Speaker 2: relevance for today. And speaking of today, Eron, I say,
Speaker 2: I promised I would get us here, where do we
Speaker 2: stand with tapeworms? Oh?
Speaker 1: I will hopefully answer that a little bit right after
Speaker 1: this break, So I don't. I don't have great numbers
Speaker 1: on overall tapeworm burdens. I'm just gonna say that one
Speaker 1: right out front, largely because, like we talked about, and
Speaker 1: like I said in the biology section, when humans get
Speaker 1: infected with adult forms, especially of Tinia sagnata Tinia solium
Speaker 1: tena asiatica, the symptoms are generally quite mild. So we
Speaker 1: just don't have solid numbers. World Health Organization on their
Speaker 1: website is.
Speaker 2: Like, we don't track it.
Speaker 1: We just don't. But suffice to say, these are incredibly,
Speaker 1: incredibly common parasites causing millions, tens of millions, hundreds of
Speaker 1: millions of infections worldwide. I do have some numbers from
Speaker 1: the fish tapeworm. Shockingly enough, a paper that I found
Speaker 1: estimated that up to twenty million people are infected worldwide
Speaker 1: with Diphilobothrium species. And that's just fish tapeworm, right, beef tapeworm,
Speaker 1: pork tape worm. These are going to be incredibly common
Speaker 1: as well. H We do have some numbers when it
Speaker 1: comes to neurosyst to circrosis as well as high data
Speaker 1: disease or it kind of caucosis okay, because unsurprisingly these
Speaker 1: cause more severe infections. So the World Health Organization reports
Speaker 1: that worldwide, the number of people estimated to be living
Speaker 1: with neurosys to circosis, that is, the cysts in the brain,
Speaker 1: is somewhere between two and a half and eight million
Speaker 1: people worldwide. Oh my gosh, right, huge number and huge range.
Speaker 2: Right.
Speaker 1: The range is because this is an estimate that includes
Speaker 1: both people who are asymptomatic and might be symptomatic, okay,
Speaker 1: and in endemic countries. And the list of endemic countries
Speaker 1: is very long. This is a globally distributed parasite. It's
Speaker 1: estimated that up to thirty percent of people living with
Speaker 1: epilepsy have neurosystics orcosis as a potential cause of their epilepsy.
Speaker 2: Wow.
Speaker 1: Yeah, And in some underresourced, impoverished rural communities in these
Speaker 1: endemic countries, it's more like seventy percent of the burden
Speaker 1: of epilepsy is due to neurosystics orcosis.
Speaker 2: I had no idea, I know.
Speaker 1: And the World Health Organization also estimates that seventy five
Speaker 1: percent of people living with neurosisis orcosis are getting little
Speaker 1: to no treatment. I know, not great when it comes
Speaker 1: to a kindo caucus the other species, multiple species of
Speaker 1: parasites which we can be the intermediate host and cause
Speaker 1: severe disease worldwide, It's estimated that there are at least
Speaker 1: a million people. One paper I read said between one
Speaker 1: and three million people worldwide living with the various forms
Speaker 1: of a kindo caucosis. Okay, so all of these parasites
Speaker 1: are globally distributed and incredibly common.
Speaker 2: I have a question about cooking mm hmm. If you
Speaker 2: follow like the standards temperatures for you know, pork and
Speaker 2: beef and so on, does that kill the cysts?
Speaker 1: Great question? Yes, sure, yes, okay. I also want to
Speaker 1: kind of emphasize that pork gets a really bad rap.
Speaker 1: But neurosisis orcosis is not caused by eating pork. It's
Speaker 1: caused by exposure to human feces that have the eggs
Speaker 1: of the parasite. So while pigs are an essential part
Speaker 1: of that life cycle because pigs are the normal intermediate host,
Speaker 1: it is not eating uncook pork that gets someone infected
Speaker 1: with neurocyst to orcosis.
Speaker 2: That's very I think a really interesting and important point,
Speaker 2: and I didn't know that before doing this episode.
Speaker 1: Yeah, and I think it's an important part because certainly
Speaker 1: you could have pig meat that becomes contaminated with human feces,
Speaker 1: especially if conditions are such that human feces is being
Speaker 1: used as fertilizer and then becomes contaminated in the pig meat, etc.
Speaker 1: That's definitely possible, but it's not the same as getting
Speaker 1: an adult tapeworm from the cysts that are in the
Speaker 1: pig meat. It's a pretty complicated life cycle. Yeah, and
Speaker 1: so unsurprisingly, prevention of this disease is the best thing
Speaker 1: that we could try and do right and as all
Speaker 1: of the complex life cycle parasites that we talk about
Speaker 1: on this podcast, prevention of a disease, like any of
Speaker 1: these tapeworm infections, requires a one health approach.
Speaker 2: One hell it does.
Speaker 1: It requires that animals can be vaccinated and treated for
Speaker 1: these parasites. It requires that adequate sanitation for both humans
Speaker 1: and livestock and domestic animals is available. It requires treatment
Speaker 1: for humans. So these are very complex diseases, all of
Speaker 1: these to try and kind of get a handle on,
Speaker 1: and that's I think a large part of the reason
Speaker 1: why they're still so widespread. M hm.
Speaker 2: That makes sense, but it also seems pretty crucial. Two
Speaker 2: and a half to eight million people I know, and.
Speaker 1: I had no idea what a large share of the
Speaker 1: overall global burden of epilepsy was due to neurocystis or
Speaker 1: coosis specifically.
Speaker 2: Yeah. Yeah, yeah, me either.
Speaker 1: So we need to do a whole episode on epilepsy,
Speaker 1: because I also tried to look into like how epilepsy
Speaker 1: and then I was like, who.
Speaker 2: Oh no, it's It's like it's on our list. Might
Speaker 2: even be on our list for this season, though I'm
Speaker 2: not entirely sure.
Speaker 1: Yeah, but that is a bunch of species of tapeworm.
Speaker 2: How about it?
Speaker 1: How about it?
Speaker 2: Are we ready for sources? I think? So, okay, I
Speaker 2: have several I'm going to shout out a few, so Hoburg,
Speaker 2: either as an individual author or Hoburg at all. There
Speaker 2: are a few papers that I really liked to understand
Speaker 2: more about the evolution of tapeworms. And then one that
Speaker 2: was really helpful for the history the human history was
Speaker 2: a paper by del Bruto and Garcia from twenty fifteen.
Speaker 2: I had a.
Speaker 1: Number papers specific to Tenia infections. Paper specific to the
Speaker 1: fish tapeworm infections, as well as a couple on a kinococcus.
Speaker 1: But I also want to give a special shout out
Speaker 1: to a series of YouTube videos that I watched that
Speaker 1: were put together by the Robert Wood Johnson Foundation and
Speaker 1: Stanford Medicine. They're available on YouTube and they're really great
Speaker 1: short clips and there's like one for each parasite species
Speaker 1: that we talked about, and they're just I really like them,
Speaker 1: so we'll link to that as well.
Speaker 2: I use that for the pronunciation Yeah, me too.
Speaker 1: That's how I found them and then I was like, Wow,
Speaker 1: these are really useful.
Speaker 2: Yeah, listen to follow and leave us a review on
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Speaker 1: Thank you to Bloodmobile for providing the music for this
Speaker 1: episode and every one of our episodes.
Speaker 2: And thank you to the Exactly Right Network, and thank.
Speaker 1: You, of course to you listeners. We love that you listen.
Speaker 1: We love making this podcast. Hope you learn some fun
Speaker 1: things about tapeworms.
Speaker 2: Yeah, absolutely, and a special thank you as always to
Speaker 2: our wonderful, generous patrons. We love you and appreciate you
Speaker 2: so much. Okay, well, until next time, wash your hands,
Speaker 2: you filthy animals. M.