As a general surgery resident, you tend to expect the unexpected and very little surprises you. But one morning during my plastic surgery rotation during my intern year stands out as a once in a lifetime experience. A patient to come in overnight who, while working with machinery, completely severed their thumb from their hand. One of the microsurgeons was able to painstakingly reattach it, giving the patient a small
but very real chance to keep their thumb. Excited to meet the patient and see the aforementioned thumb, I waited outside the room for the plastic surgery residents to join me for rounds. Once they did, I noticed a small styrofoam cup in the chief resident's hand, which I thought was interesting considering we typically don't get coffee until after rounds. He then asked me and the other residents if we were ready for this, as he showed us what was
in the cup. Starkly contrasting the inside of the white cup were four dark, undulating masses, and then it all kind of clicked at once for me reattached thumb.
We need to rest or blood flow.
Of course, these are leeches. I feel like a lot of my medical training was a process of either dispelling or reaffirming random bits of information I collected from unknown sources throughout my life, and leeches ended up being the latter. The leeches had been literally bred for this in a sterile environment, to be used once and only once placed on a future line where the reattached flesh met the hand, the leeches would feed, promoting blood flow by keeping the
blood from clotting. Then when full, they would fall off, at which point they'd be collected and a new leach would be placed, rinse, in repeat. I was told the hospital had a policy where the first leech had to be placed by a physician, and once it took to the patient, the following leaches could be placed by nurses. So we were there that morning to place the first one. The patient only spoke Spanish, so we had an interpreter via phone service help with informed consent. This is when
things truly got weird. After the chief resident explained the plan, the patient became came very uneasy and upset. After a bit of confusion, we decided to wait for an in person interpreter to try again. It turns out, during our literal game of telephone, the word leech somehow transformed into
venomous snake. Despite taking Spanish in high school, I am not fluent and I have no idea how this happened, so already off to a poor start, we spent some time basically finding different ways to say no, it's not venomous snakes, it's just leeches, which I feel is like saying no, no, don't worry, I'm not going to steal your car, just your engine and your tires. It's definitely better,
but by how much? The misinterpretation was finally sorted out and shout out to medical interpreters and all interpreters everywhere, we would be totally lost without you, and the patient finally consented to leech therapy. The resident then tried to place the first leach onto the area, but the leech had other plans and wasn't really into latching on at
the time. During what seemed like hours but was probably just a couple of minutes, the resident tried again and again to get the leech to literally bite, to no avail. With everyone in the room singularly focused on the reluctant creature, no one noticed that the cup with the other leeches in his other hand were as precariously tilted over the patient, and one adventurous leech had made its way to the lip of the cup and onto the gloved finger of
the resident. Another resident in the room finally noticed and brought it to his attention, but instead of very calmly stopping what he was doing and making very simple movements to remedy the situation, his fight or flight response kicked in. He let out what I can only describe as a genuine shriek and inadvertently dumped the cup and its contents onto the patient's lap. Needless to say, the patient was about as freaked out as humanly possible at this point,
but we did eventually get the leeches to latch. Unfortunately, and independent of these hectic events, the tissue was too far gone, did not regain enough blood flow, and the thumb could not be saved. I wish more could have been done for the patient, especially under those circumstances, and I really hope they're doing well wherever they are. But I truly appreciate the experience to learn how leeches can potentially help us even in modern times.
I just the the visual of like the leech slowly making its way and banking up the cup, the scream, and the Yeah streak. Specifically, that amazing first hand account comes from friend of the pod, doctor Robert Rowe, who is a preventative medicine physician who serves as adjunct faculty with both the University of North Carolina Preventative Medicine Residency
Program and the Gilling School of Global Public Health. He is also the creator and host of tar Heel Wellness spelled h e a L, which is a podcast dedicated to the health and well being of medical residence. It touches on physical and mental challenges that many other people face as well, and it's available wherever you get your podcasts. You should definitely check it out. Yeah, we're going to be on it at some upcoming time, I think, which will be really I'm really excited about it.
Yeah, it's going to be so fun.
But yeah, I what an amazing story. Thank you so much.
Thanks doctor ro much for not only telling us that story and then being willing to tell it again so that we could share it on the podcast, Because the first time we heard it we were like, I'm sorry, that's too good of a story.
You please please share.
Yeah.
Hi, I'm Aaron Welsh and I'm erin allman Updike and this is this podcast will kill you.
Today's as promised, an incredible companion episode to last week, all about leeches.
Just when you thought it couldn't get simultaneously grosser and cooler, it's about to.
Before researching for these two episodes, was there one or the other of these that like grossed you out more, just like as a general thing, because I feel I have an opinion about that.
Oh yeah, for me, it's maggots interesting.
Yeah, Leeches for some reason absolutely creep me out. I don't think I've ever seen one in real life, but they just I don't Something about the idea of them freaks me out.
That is very interesting because I love them both so much now like now, but I think I would still have a difficult time, like getting over the visual of maggots. Leeches don't bother me and maybe interesting, I don't know why. Also, I need to apologize and advance to you because I have some gnarly leech facts that I with and share with you. I can't wait may reinforce some of these leech wariness that you have.
It's okay, I'm mostly a saltwater girl. So I think I'm gonna be fine.
You're not. There are saltwater leeches. Oh no, this is gonna be up there.
Okay, because you know the other thing that actually terrifies me more than anything in the ocean is snakes, like sea snakes.
Oh yeah, so now.
I get to also be afraid of sea leeches apparently.
Are you afraid of terrestrial snakes?
No, not at all, love.
Them, okay, just sea snakes.
Sea snakes. Have you seen them? Swims?
Yeah? I have. And I also feel like there was a formative documentary that I watched, probably on like Animal Planet growing up, where it was like sea snakes are the deadliest of all animals.
And that is still what's burned in my memory is truth. So but today we're not talking about snakes.
No, We're here to talk about leeches. Yes, And because this is a companion piece to last week's episode on Maggots, which if you haven't listened to yet, oh my gosh, really don't be don't be too discouraged or grossed out. Well that's hert kind of a hard thing to ask, but I promise you there are some really cool nuggets of information in the Maggots episode, but because this is a companion piece, we are doing one quarantini for both episodes because it is a tale of two worms. Get it, huh?
And in a tale of two worms. In case you missed out on the Maggots episode, which again go listen to it. You can find ingredients such as vodka, lime juice, cranberry juice, pineapple juice, orange juice, ginger ale basically fruit punch, fruit punch.
It's fantastic. The full recipe, it's already up on our website, this podcast, Wikilli dot com, and all of our socials, so hopefully you've got one in hand for this episode.
Yeah, socials, follow up socials on them. We've got some good content, really, we really do. It's pretty It's pretty cool. That's all I've got to say about that. But we also have a website where you can find all sorts of cool things, including but not limited to, transcripts, the links to bookshop dot org and our Goodreads list, sources for all of our episodes, links to merch links to our Patreon, links to a first hand account form. You know, there's more stuff. There's so much our website.
Check it out. This podcast will kill You dot com yeah, well with that, should we get into leeches one, we should right after this break. So leeches are actually worms, surprise, surprise. Specifically, leeches are a type of analid worm, which are the segmented worms like your earthworms worms that people know about. And there are a lot of different species of leech, the vast majority of which are either permanent or temporary external parasites, so they suck on blood and that is
what they live on. All of the ones that are used in medicine fall under the family Hyrudinidae, which suck our blood but also like amphibian's blood. They're pretty like they'll eat a lot of different things, and a couple of the most commonly used species in medicine are Hiroudo medicinelyis what a what a logical name, and several other species of hiroudo as well, and then at least a few other species as well in nature, like when not
grown in a lab because spoilers. Just like with maggots, the ones that we use in medicine are all grown in a lab and they're all sterilized before they're used, but in nature they tend to live in like warm, shallow still pools the types of habitats that amphibians prefer, because amphibians are apparently quite a good food source for them, and leeches have classically, if you think of a leech, if you've ever seen what's that movie?
Stand by me, yes, I was thinking the same thing.
That's what I think of when I think of leeches every single time. And he goes bung. Okay. So leeches have two suckers, right, They've got one on their front end and one on their back end. And the front end is the business end. That's the end that we'll focus on. The posterior sucker they use just for clinging and for moving.
I do, I do.
And while maggots that we talked about have no biting mouth of which to speak, leeches, on the other hand, are equipped with not one, not two, but three jaws that are arranged like a pyramid. Each one of these jaws has sixty to one hundred teeth on them. Eron, I know it's terrifying. If you look at like close up images of leech jaws, it is they look like an alien. They look like they're terrifying, but that's why they leave. If you've ever seen a leech bite Mark,
it's like a little y shaped bite. It's because they've got these three jaws that come together and take the whole chunk out of you. That's so cool, I know, and also cool are leeches themselves leeches. They're very fascinating and the most useful part of leeches medicinally is by far their saliva. Leech saliva contains over one hundred bioactive substances. I'm sorry. So after they bite us with their like hundreds of teeth, leeches inject their saliva into us, and
then they suck up our blood. That's what they're feeding on. When they do this, they're sucking up several times their body weight in blood so that they can go several months, in fact, up to a year between blood meals.
Erin, erin, I have read. I'm gonna pull up my notes real quick because I wrote this in a random spot and I have just written leeches live for eighteen to twenty seven years in the wild question. I'd love to.
Say you wrote that, because I have How long does a leech live for? I still don't know. But they can fast for a year and a half. What the heck?
That is amazing.
Eighteen to twenty seven years.
Yeah, and now I'm about to fact check myself because I want to make sure that that has a citation involved. Amazing, all right, So we did just do some fact checking. We fact checked because we couldn't resist. And years is definitely on a scale of years. Some sources say up to twenty years. I did find a couple sources that said that quoted the eighteen to twenty seven and a lot of them also say like two to eight, So
it seems like there might be a range. But it seems like the maximum lifespan in a suitable environment could be upwards of twenty years, which is I mean, I never would have expected more than one year exactly.
That's like anything beyond I'm sorry, it's a warm it's a worm. It's amazing.
What's the longest lived worm? Do you think someone let us know, we're too.
Many rabbit holes, too many, too many get back to leeches. They're sucking all this blood, a whole bunch so that they can live their years in between blood meals. So for this blood to not just coagulate on removal from the body, which is what blood wants to do. That's what it does when it removes from the body. Leeches have a whole bunch of compounds in their saliva that function as anticoagulants. The first, most important and most well known and well studied is called herod in. It's like
named after the leeches, and this is pretty cool. It inhibits thrombin, which, if you want to throw all the way back to our hemophilia episode, we talked a lot in that episode about the cascade of reactions that happens in order for our blood to clot, one compound has to be activated, which activates another, and on and on and on. Thrombin is one of the final enzymes in this cascade, so that is what herod in is blocking.
It's kind of like the bottom or top, depending on which way you want to look at it, of this cascade, and it's one of the major regulatory steps in coagulation, so it's a really effective way to block coagulation. Herod In was synthesized via recombinant DNA and it's used medicinally today. We use it all the time in medicine, especially if people can't use heparin, either because they've had a reaction to it or because they're allergic or for whatever reason.
But that's not all I said. They have a hundred bioactive substances. They have a bunch of other substances that block other parts of the coagulation cascade, like factor ten a, et cetera. Blah blah blah. They also have a bunch of compounds that block platelets from aggregating allah aspirin, which means that they're stopping that first part of the coagulation
because platelets are one of the first things. But what it also means in us is that our wounds from a leech are going to ooze for a long time because platelets are one of the first things that we would use to stop, and they injected that saliva into us, right. But that's not even all. They also have a whole bunch of other enzymes. Some of them serve to increase the permeability of our connective tissue, which for the leech allows for their secretions to penetrate more deeply into our
tissues so that they work more Medicinally. What this can do is promote resorption of fluid and blood because it's increasing the permeability of the connective spaces. They also have enzymes that help to dissolve any blood clots that have already formed, and a lot of the things that they release, they're soesting much helps with vasodilation and reducing scar tissue formation. Like the list goes on, and we still don't know
the mechanisms of every one of these compounds. There's also analgesic properties that we definitely don't understand, which makes the biting of those hundreds of leech teeth, or at least the sucking process a little bit less painful, perhaps, so you can imagine that with so many amazing things present in their saliva, leeches are used for a pretty wide variety of things, or I should say they've been studied for a pretty wide variety of things, because today they're
most often used for post surgical care, especially in complicated procedures like what we heard in our first hand account with the reattachment of a finger, like skin flaps, reconstructions, places where you really don't want a lot of venous swelling or a lot of edema, like overall swelling in the tissue, because leeches are really good at reducing that kind of swelling, both by physically removing that venous blood but also by just reducing inflammation overall, and they leave
these little wounds open to ooze for a few days, which can also be beneficial. But leeches have been evaluated for a lot of other things that I found fascinating and would never have expected people to use leeches for. The one that has the most evidence thus far is in the treatment of osteoarthritis. Of all things. Huh, yeah,
that's my face too. So leeches have been studied for treatment of a lot of different kinds of arthritis, the idea being very similar that it's reducing inflammation around the joints, which is the cause of a lot of pain in arthritis, and a few larger meta analyzes seem to show some benefit in osteoorithritis at least for pain reduction and an
increase in mobility. For other types of things like rheumatorid arthritis or even ankylosinkspondylitis, there's been at least like case studies, not necessarily large studies, but people have also tried to use leeches for things like migraines, TMJ, high blood pressure, heart disease, even some neurologic disorders, and at least the published studies on these seem to show benefit, but it's a really minimal amount of data. For any of these
other conditions. You're not going to find people who are going to give you leeches for your blood pressure, like that's not a thing. But for reconstructive surgery, it absolutely is a thing. Yeah, and some people have used leeches for the treatment of chronic wounds, so you could use leeches and maggots together.
In in combination. All that's amazing. I know that. That is leeches, you know, I love them.
Their saliva is incredible.
It's magic. Yeah, it's more powerful than magic. It's nature.
So Aaron, tell me, yeah, tell me about the history of these little suckers, get it nice?
Uh?
Yeah, I can absolutely do that. Let's take a quick break and then I'll tell you as much as I can about leeches. All right, Before I get into the long, long history of leeches used in medicine, I wanted to first take a bit of time to just get to know this group of animals a little bit more broadly. Okay, so much fun. And estimated seven hundred species of leeches have been described, did you wow? Seven hundred? Yeah, and they can be found on all continents and seas except Antarctica.
They live in caves, in saltwater, in fresh water, in hot water, in freezing water, in shallow water, in deep water. The record is over seventy eight hundred meters yep. I have to.
Say these last two episodes are making me feel like I did all of my invertebrate zoology classes poorly by not remember any of this.
Oh, if I once knew this, I have long forgotten it.
Maybe I just never learned it. But like, okay, you.
Keep going, please, okay, okay. They leeches also live in arsenic laced water, in super alkaline water, not in water at all, but on moist land. It's pretty rad Okay, a land leach, a land leech. And okay, if we say picture a leech, most of us are going to picture those leeches from stand by Me that we talked about, or something very similar. But did you know that only about half of leeches feed on blood?
No? I thought most of them dead half half half? But are most of them still parasitic?
Well?
The other ones feed on things like earthworms, gastropods, crustaceans, and insect larvae like.
As parasites more as like just cavor predators.
Yeah. Yeah, one of the biggest leeches, reaching lengths of up to three hundred millimeters, which is nearly one foot eleven point eight inches. Uh, preys on worms.
It eats other worms.
It eats other worms. But the biggest leech, I'm going to try to pronounce this Hementaria GILLANII, gets up to four hundred and fifty millimeters long seventeen point seven inches erin.
That is very large for a worm.
Nearly four inches in width. And this guy does feed on blood. Who's blood, lots of different types of blood. So humans have been observed rabbits, cows, birds, Okay, but how do leeches find their prey, you might ask? They
use many different sensory clues. As a matter of fact, So terrestrial leeches sense things like ground vibrations, whether the leaves and dirt or whatever they're laying in gets moved around or disturbed, shadows, air currents, and maybe, although it's been debated co two from the breath of their intended prey. Aquatic leeches use things like water currents or temperature or disturbance to detect prey. It's amazing and I have several more. If you don't mind me sharing a few more cool
bits of leech trivia. Okay please. Leeches can live in extreme temperatures, not like the same leach or the same leech species, but for example, the freshwater leach. This is the names of these leeches. I'm telling you what challenging. Ozobrancis jancianus quote survived at negative one hundred and ninety six degrees celsius for twenty four hours and up to thirty two months at minus nine degree celsius.
Wow.
And on the other side of the spectrum, the marine leech. Oh, this is the hardest one of all. I think it's the last one. No, it's not. I see another one down there. Zeylanicobdella arugamensis has been found to survive at temperatures from twenty degrees celsius to forty degrees celsius, which is sixty eight to one hundred and four degrees fahrenheit. Blood feeding leeches can also get creative with where they feed, such as up the nostrils or behind the eyeballs of humans and livestock.
Did you just say behind the eyeballs?
Yeah? Apparently no? No, eh, at least I think it the eyelid. Yeah, okay, uh huh h. But I think the one in terms of unique feeding location choices, the one that takes the cake is Placo Deloit's Jaeger SKIOLDI, which I know that I totally did not pronounce correctly, but like, I'm sorry. This leech actively swims, it can actively swim, and it does this swims to its hippopotamus host, where it will invade the hippo's rectum and commence blood feeding only.
In the rectum, poor hippo.
Yeah, but now that I've completely spent all of the goodwill that we had previously built up for leeches, let me attempt to like bring you all back on board.
Get you to like a leech again.
Yeah. I know that it's like we're it's an uphill battle, but I think that we can do it because I want to tell you about leech reproduction, especially parental care. What parental care exactly? See goodwill returned. So, First of all, leeches have both male and female reproductive organs, which means that while they don't always or even often self fertilized, they absolutely can and that's this does happen. And second, leeches produce these things called cocoons, which come in lots
of different textures. But that's where leech eggs develop inside this cocoon with like a nutrient soup that lasts until the eggs turn into juveniles and then can strike out on their own. Huh, it's so cute. But some leeches go beyond the cocoon. Leeches in the gloss of Phonia day care for their eggs both before and after they hatch, either in a little cocoon nest or on their body or in a little pouch like a kangaroo.
Little kangaroo leech pouch.
Uh huh. Once the eggs have hatched, some leeches will bring them food like snails or mosquito larvae or quote by transferring nutrients across the body wall to the developing young in a manner reminiscent of a placenta. Oh, isn't that amazing? But there's more, because researchers have observed that in times where food is scarce, some leech parents will
starve themselves so that they're young can feed. Wow. Some species live in groups with adults and young together, sharing food and even caring for young that aren't their own.
I don't think I ever thought about leeches, even worm like behavior.
This much I know, and it is incredible. I am in awe interesting. Yeah. Yeah, the diversity found among leeches is incredible, and there are so many species that haven't yet been studied, or haven't been studied very much, or have yet to be discovered on their own. Leeches are amazing. But if you want a human centric perspective to convince you that leeches are worthy of study and conservation, consider the powerful anticoagulant herodin found in the medicinal leeches saliva
and how it's now used in medicine. That's just one of the amazing compounds found in that leech species saliva, and there are many more leeches with many other cool salivary compounds like hemantin and anticoagulant found in the giant Amazon leech that targets fibrinogen formed blood clots, theremine which inhibits thrombin like herodin, but it seems to be different. And then there's the bacterial endosymbions of leeches. Leeches that feed on blood have bacteria that will help break down
blood and provide essential vitamins. So if you want this human centric reason for why preserving biodiversity is important. Consider the leech, like not just the medicinal leech, but all leeches. But now turning towards the medicinal leech, which actually turns out might be made up of multiple species or like morphs or something. Yeah, let's get into how humans have used these leeches throughout history. Okay, like maggots, The use
of leeches in medicine goes way way back. I'm talking fifteen hundred BCE ancient Egypt, murals in a tomb depicting the bloodsucking powers of a leech. Wayback.
Wow.
Yeah, ancient Mesopotamia, ancient India, ancient Greece, and Rome, likely in ancient Central and South America, ancient China. There's evidence that leeches have been used medicinally all around the world for thousands of years. And this isn't a case of like an occasional mention or reaching for the leech only
when everything else failed. Leeches were a very regular treatment in many places around the world for millennia, so much so that, Okay, the etymology does get a little tricky because when we were setting up for this episode, I was like, let me just refresh my etymology notes and make sure that I am right in this, And it turns out I wasn't. It turns out the truth is
a little more complicated. So, okay, my initial reading and a lot of papers will say that the word leech may have come from the Old English word lay say, meaning physician. Okay, turns out that there were two. From what I can tell, there's one paper that talks about there being two independent origins and meanings for that word lace or lay say, meaning one meaning physician and one for leech. And then the two kind of merged because for a really long time one of the synonyms for
a physician was leech. Interesting because doctors used leeches so frequently, So it.
Wasn't that like the name leech came from doctors. It was like they called them the same thing because they used them so much.
Maybe yes, I think that definitely their meanings merged to a certain degree or something to that effect. I'll link to the paper that goes more into the etymology. But like it, it's like we don't know which came first, and whether leech was for the worm, and then physician became known as a leech or leech became known from physician,
and it sounded maybe like the worm something like that. Okay, Anyway, it makes sense that the two would be synonymous over much of the ancient world up until the eighteen hundreds or so because of what we know about medicine during this long period of time, i e. That it was obsessed with blood and blood letting. So these these leeches took up residence as like a permanent tool, almost in
the phlebotomous toolkit. So I've talked about the humoral theory of disease like one million times exactly on this podcast exactly. So here's one million and one just for a refresher. Essentially, there were thought to be four humors in the body, yellow bile, black bile, phlegm, and blood. Diseases resulted from an imbalance in the four humors. So that could mean too much blood, in which case you do some blood
letting until the balance is restored. In the blood letter's toolkit, you could find things like lances, little pocket knives called flemes, bleeding cups, syringes. Because certain situations required certain solutions, many of these tools were just like a brute force attack, like we need to get a lot of blood out
of you, and we need to do it now. Leeches came in handy when a gentle touch was warranted, when the desired volume of blood removed was on the order of millily rather than leaders, or when the area that needed bleeding was in a particularly sensitive or hard to reach zone. Okay, like in cases of hemorrhoidal congestion, rectal prolapse, volvo vaginitis, orchi epididimitis, hydroceal laryngitis, tonsilitis tonsilitis erin, tonsilitis
what I know, inflammation of the cervix ouch. Yeah, even some eye conditions.
Yees yeah wowow.
But even though it's like really hard to think about and makes me feel squirmy, this would have been less painful than the like a blade on a spring like some of these blood letters tools definitely, and like you mentioned, Aaron, leeches were also used for wound healing. Latifel Baghdati in the twelfth century described how leeches were helpful in tissue cleansing after surgery, which is amazing.
I love it.
And unlike maggots, who, like we talked about, their popularity seemed to wax and wane over the centuries, leeches were just like on the up until the late nineteenth century in the Middle Ages and Renaissance, sometimes referred to as the Golden Age, for blood letting and leeching, leeches were used by barber surgeons who would have their patients grip a rod, which would possibly later inspire the barber pole.
You know, like the poles that have that. Yep, So that might have been a symbolism for like, grip the rod because this will cause your veins to swell and that'll make it easier for the leeches to latch onto to start the bleeding.
Interesting.
Yeah, and then just because I want to expand a little bit on the classic barber pole, because what else am I going to be able to do it on the podcast? Okay, you can picture right like it has, yeah, the pole, it has the spinning ribbons, it has blue, red, and white often.
Yeah.
It has been suggested that the red ribbon theyse all carry, meaning the red ribbon, originally came from barbers advertising their services by wrapping the bloody linen from a former patient around the pole, showing hey we do blood letting here. The red means hey, I can bleed you. The white ribbon was I can pull teeth and set bones, and the blue said I can give you a nice trim or shave. Those were allegedly it's one idea as to the possible origins of those ribbons. Isn't that great?
What a wild time to live in?
I know, I know, I know. Wow. And so if you're like, okay, I really want to go get my hair cut, but you see the barber pole just has red and white, like you're you can get bled, but you're not going to have a fresh.
Shit's they're not going to do trim. Okay.
Yeah. Anyway, as the popularity of leeches grew over the Middle Ages and Renaissance, so did its possible applications from neurological and psychiatric conditions like epilepsy to STIs, gastritis, diseases of the eye. I just keep seeing uterine applications mentioned m boiss Pire, that French surgeon from the fifteen hundreds. He dedicated an entire chapter to leeches in his massive treatise,
and things were only going to get leechier. I don't know what exactly constitutes like the golden age of something, but I find it hard to believe that like that, the Middle Ages and Renaissance for the Golden Age, when their popularity only continued to grow into the seventeen hundreds and eighteen hundreds too, really unbelievable levels. So peak use was in the early eighteen hundreds. Okay, In Europe, physicians and barbers kept leeches handy in their offices, in leech jars.
Some of these jars, Aaron, have you seen pictures of them? No, they're beautiful. They're like these beautiful ornate jars that have like carved little accessories with like gilded whatever, and it says leeches across the front of it. I immediately went on eBay, like in the middle of researching, and I was like, I need to find an antique leech jar. I can't find. I can only find a replica. But it's going to be now my life's quest to find a leach jar.
We should go back to the Surgical Sciences Museum in Chicago, because I bet if they don't have it, they will know where you get it.
I love them. We'll post a picture because we have to. But perhaps no one loved leeches more than Francois Joseph Victor Bruce, one of Napoleon's physicians, Napoleon himself had leeches to treat hemorrhoids. So cool thing.
I feel like that would be effective.
I think so too. Yeah, has that is that one of the proposed treatments for today?
Uh No, I mean Verico's veins, yes, but yes, legs. I think that we just have other options these days. But I didn't see anything about people using leeches like instead of surgery for hemorrhoids. So it's a good, good thought, all right, somebody propose it, mm hmm. Maybe it's out there and I just missed it.
Anyway. Bruce was such a fan of blood letting and especially leeching, that he was nicknamed quote the vampire of medicine. He thought that every disease was attributable to inflammation, especially of the GI tract. So like, no matter what the condition asthma, broken wrist, smallpox, sore throat, pink eye, it all came down to gas and to write us, of course,
all of it. And so in one example I saw, he prescribed the patient a starvation diet and all of the leeches that could fit on their abdomen because that's where he thought that inflammation would come out of their abdomen. Oh, no, somebody was described as looking like they were wearing quote a black glittering coat of mail end quote change. Oh god, totally yep. And his enthusiasm for leeches may have been unmatched, but he was not alone in his love for them.
Between eighteen twenty nine and eighteen thirty six, So over those seven years, do you have a rough guess as to how many leeches were used yearly in Parisian hospitals? L. Harris, Yeah, you don't have to guess if you're like, I don't even.
Know, I don't know. Hundreds of thousand's.
Five to six million each year? Off?
Is that why they're basically extinct in the wild.
Yes, this is exactly why. This is why this was a total of eighty four thousand kilograms of blood drawn annually. Unfathomable, it really is.
Oh wow.
A millions more of the medicinal leech, the Heruda medicinalis, were exported to the US from Europe. At one point thirty million leeches per year exported to that reported to the US. Yeah, oh my. And so this huge demand even at the time, drove leeches close to extinction, and rewards were offered for people who could find a way to breed them in the US or find alternative species that were as effective without causing harm.
Wow.
And eventually this demand would die down as the medicinal leech faced the same fate in the late eighteen hundreds, as did maggot therapy. Medical advancements like germ theory, a better understanding of human anatomy and physiology, and the use of statistics showing that blood letting overall was useless to harmful for most conditions that they had been used for all sent these leeches mostly packing with a few physicians
hanging onto the practice. And also I get that, like you have this beautiful leach star and you're like, what do you want me to do? Just like not use this? Put something else in it?
No thing, just keep one for just a couple of years, And like, can't just use it every year?
Right, it's got to come back, Right, It's just like low wasted Jens Low writers, it's going to come back.
Those can't come back.
It's terrible. I'm not happy about it. But anyway, Also, like the maggot, the leech would experience a renaissance later in the twentieth century barbers, because barber surgeons and physicians had. I've noticed the anti coagulant effects of leeches for a long time, how like an area where a leech had been attached would continue to bleed longer than if the wound had been made by something else, like you talked about.
And in the eighteen eighties, researchers succeeded in extracting the substance that led to this anti coagulant effect, which was called herodin in nineteen oh four. For decades, challenges with extractions, like how it would take an estimated fifty thousand leashes a year to get enough herod in for scientific study, and that people who were treated with the extract experienced shock because it probably wasn't like properly purified in its extraction.
This limited its use or investigation. But then, like you mentioned aaron, in the nineteen eighties, researchers succeeded in engineering the substance, and that's allowed people to study this incredibly powerful anti coagulant for all kinds of applications. And leeches themselves have experienced a bit of renaissance in the field of surgery, especially plastic and reconstructive or microsurgeries, beginning in
the nineteen sixties. In two thousand and four is when the FDA certified leeches as a medical device, and it seems like people are getting back on board with these
powerful little parasitic worms. Like I'm fully on board. I feel like what it comes down to, not just with leeches, but with maggots two in terms of medicine, is that we don't always have to reinvent the wheel, and that there may exist things that people have used for a really long time that could be really powerful or maybe they're not powerful, but also maybe we should check it out on a case by case basis and see what we find, because it could be something like leeches, it
could be something like maggots. And I think that these past couple episodes have just been so thrilling and fun and interesting to put together. And I can absolutely say that I have so much more appreciation both leeches and maggots, and now I can't pick a favorite.
Yeah, same, Like, I love that they both exist. I love that they both were like licensed by the FDA for use. I know, fascinating.
Yeah, well sources, sources, I think, so okay.
We can all learn more.
We can. I am going to shout out too so if you want to learn some more leech facts and that wasn't enough for you, which who doesn't. Honestly, there's so much more in this great paper by Phillips at All from twenty twenty titled Leeches in the Extreme Morphological, Physiological and Behavioral Adaptations to inhospitable habitats.
Leeches in the Extreme. I love that China, I know.
And then the second paper that was mostly about the history of leeches in medicine was a paper by Montoni and Manelli from twenty twenty two titled From Ancient Leech to Direct Thrombin Inhibitors and Beyond New from Old fab.
I had just a few papers and one book that I used predominantly one chapter of and this book actually had some information about maggot therapy as well. The book was titled Biotherapy History, Principles and Practice, and they had an entire chapter on hiroudotherapy or the use of leeches, and then a chapter on maggot therapy that I used
a little bit of last episode. And then a few other papers on how leeches are used today and on all of the incredible compounds that we found in their saliva, and the future of all of that, but you can find the list of all of the sources from this episode and every single one of our episodes on our website this podcast will Kill You dot com under the episode s tab A.
Big thank you again to doctor Row for just an amazing story.
Such an incredible story. Thank you so much for sharing it with us. Thank you also to Bloodmobile for providing the music for this episode in every single one of our episodes.
Thank you to Leana Scolacci and Tom Bryfogel for the audio mixing.
Thank you to Exactly Right Network, and.
Thank you to you listeners. You know you made it, you did. Congratulations. What do you think about leeches and maggots? Do you have a favorite do you have a favorite fun fact? Do you have a favorite gross fact?
Do you love them?
Do you love them as we love them?
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We do. Until next time, wash your hands.
You filthy animals. Um