WEBVTT - Ep 142 Leeches: It’s more powerful than magic, it’s nature 0:00:00.200 --> 0:00:02.400 As a general surgery resident, you tend to expect the 0:00:02.480 --> 0:00:06.200 unexpected and very little surprises you. But one morning during 0:00:06.200 --> 0:00:09.480 my plastic surgery rotation during my intern year stands out 0:00:09.520 --> 0:00:12.800 as a once in a lifetime experience. A patient to 0:00:12.800 --> 0:00:16.280 come in overnight who, while working with machinery, completely severed 0:00:16.320 --> 0:00:19.680 their thumb from their hand. One of the microsurgeons was 0:00:19.720 --> 0:00:23.680 able to painstakingly reattach it, giving the patient a small 0:00:23.760 --> 0:00:27.280 but very real chance to keep their thumb. Excited to 0:00:27.280 --> 0:00:30.120 meet the patient and see the aforementioned thumb, I waited 0:00:30.160 --> 0:00:32.440 outside the room for the plastic surgery residents to join 0:00:32.440 --> 0:00:35.200 me for rounds. Once they did, I noticed a small 0:00:35.240 --> 0:00:38.200 styrofoam cup in the chief resident's hand, which I thought 0:00:38.200 --> 0:00:42.120 was interesting considering we typically don't get coffee until after rounds. 0:00:42.800 --> 0:00:45.040 He then asked me and the other residents if we 0:00:45.040 --> 0:00:47.199 were ready for this, as he showed us what was 0:00:47.240 --> 0:00:50.680 in the cup. Starkly contrasting the inside of the white 0:00:50.720 --> 0:00:55.840 cup were four dark, undulating masses, and then it all 0:00:55.920 --> 0:00:59.200 kind of clicked at once for me reattached thumb. 0:00:59.360 --> 0:01:00.840 We need to rest or blood flow. 0:01:01.200 --> 0:01:03.960 Of course, these are leeches. I feel like a lot 0:01:03.960 --> 0:01:06.720 of my medical training was a process of either dispelling 0:01:06.880 --> 0:01:09.880 or reaffirming random bits of information I collected from unknown 0:01:09.880 --> 0:01:13.120 sources throughout my life, and leeches ended up being the latter. 0:01:14.480 --> 0:01:16.720 The leeches had been literally bred for this in a 0:01:16.800 --> 0:01:20.480 sterile environment, to be used once and only once placed 0:01:20.520 --> 0:01:23.160 on a future line where the reattached flesh met the hand, 0:01:23.760 --> 0:01:26.440 the leeches would feed, promoting blood flow by keeping the 0:01:26.440 --> 0:01:29.880 blood from clotting. Then when full, they would fall off, 0:01:30.080 --> 0:01:32.240 at which point they'd be collected and a new leach 0:01:32.280 --> 0:01:36.280 would be placed, rinse, in repeat. I was told the 0:01:36.280 --> 0:01:38.240 hospital had a policy where the first leech had to 0:01:38.280 --> 0:01:40.560 be placed by a physician, and once it took to 0:01:40.600 --> 0:01:43.360 the patient, the following leaches could be placed by nurses. 0:01:43.959 --> 0:01:47.520 So we were there that morning to place the first one. 0:01:47.680 --> 0:01:50.640 The patient only spoke Spanish, so we had an interpreter 0:01:50.760 --> 0:01:54.480 via phone service help with informed consent. This is when 0:01:54.520 --> 0:01:59.040 things truly got weird. After the chief resident explained the plan, 0:01:59.360 --> 0:02:03.800 the patient became came very uneasy and upset. After a 0:02:03.840 --> 0:02:06.240 bit of confusion, we decided to wait for an in 0:02:06.280 --> 0:02:10.880 person interpreter to try again. It turns out, during our 0:02:10.960 --> 0:02:15.000 literal game of telephone, the word leech somehow transformed into 0:02:15.160 --> 0:02:20.440 venomous snake. Despite taking Spanish in high school, I am 0:02:20.480 --> 0:02:23.160 not fluent and I have no idea how this happened, 0:02:24.080 --> 0:02:26.600 so already off to a poor start, we spent some 0:02:26.639 --> 0:02:29.680 time basically finding different ways to say no, it's not 0:02:29.840 --> 0:02:33.800 venomous snakes, it's just leeches, which I feel is like 0:02:33.919 --> 0:02:36.480 saying no, no, don't worry, I'm not going to steal 0:02:36.480 --> 0:02:41.280 your car, just your engine and your tires. It's definitely better, 0:02:41.560 --> 0:02:46.640 but by how much? The misinterpretation was finally sorted out 0:02:47.040 --> 0:02:50.520 and shout out to medical interpreters and all interpreters everywhere, 0:02:51.000 --> 0:02:54.520 we would be totally lost without you, and the patient 0:02:54.639 --> 0:02:58.280 finally consented to leech therapy. The resident then tried to 0:02:58.320 --> 0:03:00.959 place the first leach onto the area, but the leech 0:03:01.000 --> 0:03:04.280 had other plans and wasn't really into latching on at 0:03:04.280 --> 0:03:07.919 the time. During what seemed like hours but was probably 0:03:08.040 --> 0:03:10.840 just a couple of minutes, the resident tried again and 0:03:10.919 --> 0:03:14.280 again to get the leech to literally bite, to no avail. 0:03:15.200 --> 0:03:18.560 With everyone in the room singularly focused on the reluctant creature, 0:03:19.240 --> 0:03:21.720 no one noticed that the cup with the other leeches 0:03:22.120 --> 0:03:25.840 in his other hand were as precariously tilted over the patient, 0:03:26.200 --> 0:03:29.000 and one adventurous leech had made its way to the 0:03:29.040 --> 0:03:31.960 lip of the cup and onto the gloved finger of 0:03:32.040 --> 0:03:35.680 the resident. Another resident in the room finally noticed and 0:03:35.680 --> 0:03:38.920 brought it to his attention, but instead of very calmly 0:03:39.000 --> 0:03:42.000 stopping what he was doing and making very simple movements 0:03:42.000 --> 0:03:45.600 to remedy the situation, his fight or flight response kicked in. 0:03:46.400 --> 0:03:49.160 He let out what I can only describe as a 0:03:49.320 --> 0:03:55.280 genuine shriek and inadvertently dumped the cup and its contents 0:03:55.360 --> 0:03:58.560 onto the patient's lap. Needless to say, the patient was 0:03:58.600 --> 0:04:01.120 about as freaked out as humanly possible at this point, 0:04:02.040 --> 0:04:05.680 but we did eventually get the leeches to latch. Unfortunately, 0:04:06.040 --> 0:04:09.360 and independent of these hectic events, the tissue was too 0:04:09.400 --> 0:04:12.320 far gone, did not regain enough blood flow, and the 0:04:12.400 --> 0:04:15.880 thumb could not be saved. I wish more could have 0:04:15.880 --> 0:04:19.960 been done for the patient, especially under those circumstances, and 0:04:20.040 --> 0:04:23.360 I really hope they're doing well wherever they are. But 0:04:23.640 --> 0:04:27.599 I truly appreciate the experience to learn how leeches can 0:04:27.720 --> 0:05:06.920 potentially help us even in modern times. 0:05:16.200 --> 0:05:22.599 I just the the visual of like the leech slowly 0:05:22.680 --> 0:05:26.120 making its way and banking up the cup, the scream, 0:05:26.320 --> 0:05:35.520 and the Yeah streak. Specifically, that amazing first hand account 0:05:35.880 --> 0:05:40.160 comes from friend of the pod, doctor Robert Rowe, who 0:05:40.240 --> 0:05:44.480 is a preventative medicine physician who serves as adjunct faculty 0:05:44.520 --> 0:05:48.160 with both the University of North Carolina Preventative Medicine Residency 0:05:48.160 --> 0:05:51.599 Program and the Gilling School of Global Public Health. He 0:05:51.720 --> 0:05:55.760 is also the creator and host of tar Heel Wellness 0:05:56.080 --> 0:05:59.560 spelled h e a L, which is a podcast dedicated 0:05:59.560 --> 0:06:02.440 to the health and well being of medical residence. It 0:06:02.480 --> 0:06:05.920 touches on physical and mental challenges that many other people 0:06:06.000 --> 0:06:09.039 face as well, and it's available wherever you get your podcasts. 0:06:09.040 --> 0:06:11.320 You should definitely check it out. Yeah, we're going to 0:06:11.400 --> 0:06:13.880 be on it at some upcoming time, I think, which 0:06:13.920 --> 0:06:15.880 will be really I'm really excited about it. 0:06:16.000 --> 0:06:17.280 Yeah, it's going to be so fun. 0:06:17.800 --> 0:06:22.800 But yeah, I what an amazing story. Thank you so much. 0:06:22.800 --> 0:06:25.479 Thanks doctor ro much for not only telling us that 0:06:25.520 --> 0:06:27.800 story and then being willing to tell it again so 0:06:27.880 --> 0:06:29.640 that we could share it on the podcast, Because the 0:06:29.640 --> 0:06:31.640 first time we heard it we were like, I'm sorry, 0:06:31.720 --> 0:06:33.000 that's too good of a story. 0:06:33.440 --> 0:06:34.960 You please please share. 0:06:35.160 --> 0:06:37.280 Yeah. 0:06:37.360 --> 0:06:40.800 Hi, I'm Aaron Welsh and I'm erin allman Updike and 0:06:41.000 --> 0:06:42.800 this is this podcast will kill you. 0:06:43.400 --> 0:06:48.359 Today's as promised, an incredible companion episode to last week, 0:06:48.800 --> 0:06:49.880 all about leeches. 0:06:50.920 --> 0:06:57.240 Just when you thought it couldn't get simultaneously grosser and cooler, 0:06:57.800 --> 0:06:58.719 it's about to. 0:07:00.120 --> 0:07:03.760 Before researching for these two episodes, was there one or 0:07:03.839 --> 0:07:06.559 the other of these that like grossed you out more, 0:07:06.720 --> 0:07:09.440 just like as a general thing, because I feel I 0:07:09.560 --> 0:07:11.000 have an opinion about that. 0:07:11.440 --> 0:07:14.360 Oh yeah, for me, it's maggots interesting. 0:07:15.040 --> 0:07:19.280 Yeah, Leeches for some reason absolutely creep me out. I 0:07:19.280 --> 0:07:21.320 don't think I've ever seen one in real life, but 0:07:21.400 --> 0:07:24.800 they just I don't Something about the idea of them 0:07:24.840 --> 0:07:25.559 freaks me out. 0:07:26.200 --> 0:07:31.680 That is very interesting because I love them both so 0:07:31.880 --> 0:07:35.960 much now like now, but I think I would still 0:07:36.000 --> 0:07:40.720 have a difficult time, like getting over the visual of maggots. 0:07:40.800 --> 0:07:44.560 Leeches don't bother me and maybe interesting, I don't know why. Also, 0:07:46.120 --> 0:07:48.320 I need to apologize and advance to you because I 0:07:48.360 --> 0:07:51.679 have some gnarly leech facts that I with and share 0:07:51.760 --> 0:07:55.720 with you. I can't wait may reinforce some of these 0:07:56.160 --> 0:07:58.000 leech wariness that you have. 0:08:00.600 --> 0:08:02.720 It's okay, I'm mostly a saltwater girl. So I think 0:08:02.760 --> 0:08:03.680 I'm gonna be fine. 0:08:04.360 --> 0:08:13.360 You're not. There are saltwater leeches. Oh no, this is 0:08:13.360 --> 0:08:13.920 gonna be up there. 0:08:13.920 --> 0:08:16.280 Okay, because you know the other thing that actually terrifies 0:08:16.320 --> 0:08:19.040 me more than anything in the ocean is snakes, like 0:08:19.080 --> 0:08:19.720 sea snakes. 0:08:20.280 --> 0:08:22.480 Oh yeah, so now. 0:08:22.320 --> 0:08:24.840 I get to also be afraid of sea leeches apparently. 0:08:25.120 --> 0:08:27.720 Are you afraid of terrestrial snakes? 0:08:28.000 --> 0:08:29.120 No, not at all, love. 0:08:29.000 --> 0:08:30.880 Them, okay, just sea snakes. 0:08:31.200 --> 0:08:33.559 Sea snakes. Have you seen them? Swims? 0:08:34.160 --> 0:08:35.800 Yeah? I have. And I also feel like there was 0:08:35.840 --> 0:08:39.720 a formative documentary that I watched, probably on like Animal 0:08:39.720 --> 0:08:42.079 Planet growing up, where it was like sea snakes are 0:08:42.120 --> 0:08:45.120 the deadliest of all animals. 0:08:44.720 --> 0:08:47.720 And that is still what's burned in my memory is truth. 0:08:47.880 --> 0:08:50.360 So but today we're not talking about snakes. 0:08:50.760 --> 0:08:54.440 No, We're here to talk about leeches. Yes, And because 0:08:54.480 --> 0:08:58.040 this is a companion piece to last week's episode on Maggots, 0:08:58.360 --> 0:09:00.640 which if you haven't listened to yet, oh my gosh, 0:09:00.840 --> 0:09:04.960 really don't be don't be too discouraged or grossed out. 0:09:05.360 --> 0:09:07.360 Well that's hert kind of a hard thing to ask, 0:09:07.440 --> 0:09:10.040 but I promise you there are some really cool nuggets 0:09:10.080 --> 0:09:13.599 of information in the Maggots episode, but because this is 0:09:13.640 --> 0:09:16.880 a companion piece, we are doing one quarantini for both 0:09:16.960 --> 0:09:22.520 episodes because it is a tale of two worms. Get it, huh? 0:09:22.600 --> 0:09:24.880 And in a tale of two worms. In case you 0:09:24.920 --> 0:09:27.720 missed out on the Maggots episode, which again go listen 0:09:27.720 --> 0:09:33.360 to it. You can find ingredients such as vodka, lime juice, 0:09:33.360 --> 0:09:37.800 cranberry juice, pineapple juice, orange juice, ginger ale basically fruit punch, 0:09:37.920 --> 0:09:38.680 fruit punch. 0:09:38.720 --> 0:09:43.320 It's fantastic. The full recipe, it's already up on our website, 0:09:43.360 --> 0:09:45.600 this podcast, Wikilli dot com, and all of our socials, 0:09:45.600 --> 0:09:48.360 so hopefully you've got one in hand for this episode. 0:09:48.679 --> 0:09:52.600 Yeah, socials, follow up socials on them. We've got some 0:09:52.679 --> 0:09:57.680 good content, really, we really do. It's pretty It's pretty cool. 0:09:58.559 --> 0:10:00.560 That's all I've got to say about that. But we 0:10:00.600 --> 0:10:02.880 also have a website where you can find all sorts 0:10:02.920 --> 0:10:06.640 of cool things, including but not limited to, transcripts, the 0:10:06.679 --> 0:10:10.520 links to bookshop dot org and our Goodreads list, sources 0:10:10.520 --> 0:10:13.240 for all of our episodes, links to merch links to 0:10:13.240 --> 0:10:16.880 our Patreon, links to a first hand account form. You know, 0:10:16.920 --> 0:10:20.080 there's more stuff. There's so much our website. 0:10:20.160 --> 0:10:23.839 Check it out. This podcast will kill You dot com yeah, 0:10:23.880 --> 0:10:29.440 well with that, should we get into leeches one, we 0:10:29.480 --> 0:11:13.599 should right after this break. So leeches are actually worms, surprise, surprise. Specifically, 0:11:13.760 --> 0:11:16.280 leeches are a type of analid worm, which are the 0:11:16.360 --> 0:11:19.760 segmented worms like your earthworms worms that people know about. 0:11:21.040 --> 0:11:24.400 And there are a lot of different species of leech, 0:11:25.600 --> 0:11:30.000 the vast majority of which are either permanent or temporary 0:11:30.320 --> 0:11:34.720 external parasites, so they suck on blood and that is 0:11:34.760 --> 0:11:37.440 what they live on. All of the ones that are 0:11:37.520 --> 0:11:42.439 used in medicine fall under the family Hyrudinidae, which suck 0:11:42.840 --> 0:11:46.000 our blood but also like amphibian's blood. They're pretty like 0:11:46.040 --> 0:11:50.360 they'll eat a lot of different things, and a couple 0:11:50.400 --> 0:11:54.959 of the most commonly used species in medicine are Hiroudo 0:11:55.480 --> 0:12:00.240 medicinelyis what a what a logical name, and several other 0:12:00.320 --> 0:12:03.040 species of hiroudo as well, and then at least a 0:12:03.040 --> 0:12:06.920 few other species as well in nature, like when not 0:12:07.040 --> 0:12:10.520 grown in a lab because spoilers. Just like with maggots, 0:12:10.679 --> 0:12:12.760 the ones that we use in medicine are all grown 0:12:12.800 --> 0:12:15.680 in a lab and they're all sterilized before they're used, 0:12:16.240 --> 0:12:18.440 but in nature they tend to live in like warm, 0:12:18.640 --> 0:12:23.320 shallow still pools the types of habitats that amphibians prefer, 0:12:23.400 --> 0:12:27.079 because amphibians are apparently quite a good food source for them, 0:12:27.400 --> 0:12:30.400 and leeches have classically, if you think of a leech, 0:12:30.559 --> 0:12:32.400 if you've ever seen what's that movie? 0:12:33.360 --> 0:12:38.880 Stand by me, yes, I was thinking the same thing. 0:12:39.760 --> 0:12:41.640 That's what I think of when I think of leeches 0:12:41.760 --> 0:12:45.679 every single time. And he goes bung. Okay. So leeches 0:12:45.720 --> 0:12:48.400 have two suckers, right, They've got one on their front 0:12:48.480 --> 0:12:51.559 end and one on their back end. And the front 0:12:51.679 --> 0:12:54.920 end is the business end. That's the end that we'll 0:12:54.960 --> 0:12:58.880 focus on. The posterior sucker they use just for clinging 0:12:58.960 --> 0:12:59.760 and for moving. 0:13:03.400 --> 0:13:04.720 I do, I do. 0:13:06.960 --> 0:13:10.480 And while maggots that we talked about have no biting 0:13:10.520 --> 0:13:13.959 mouth of which to speak, leeches, on the other hand, 0:13:14.120 --> 0:13:20.440 are equipped with not one, not two, but three jaws 0:13:20.480 --> 0:13:24.439 that are arranged like a pyramid. Each one of these 0:13:24.600 --> 0:13:29.320 jaws has sixty to one hundred teeth on them. Eron, 0:13:30.480 --> 0:13:33.720 I know it's terrifying. If you look at like close 0:13:33.800 --> 0:13:38.520 up images of leech jaws, it is they look like 0:13:38.760 --> 0:13:44.680 an alien. They look like they're terrifying, but that's why 0:13:44.679 --> 0:13:47.080 they leave. If you've ever seen a leech bite Mark, 0:13:47.120 --> 0:13:49.520 it's like a little y shaped bite. It's because they've 0:13:49.520 --> 0:13:53.240 got these three jaws that come together and take the 0:13:53.240 --> 0:13:56.400 whole chunk out of you. That's so cool, I know, 0:13:57.960 --> 0:14:02.800 and also cool are leeches themselves leeches. They're very fascinating 0:14:02.920 --> 0:14:09.160 and the most useful part of leeches medicinally is by 0:14:09.240 --> 0:14:18.000 far their saliva. Leech saliva contains over one hundred bioactive substances. 0:14:19.200 --> 0:14:23.480 I'm sorry. So after they bite us with their like 0:14:23.720 --> 0:14:27.760 hundreds of teeth, leeches inject their saliva into us, and 0:14:27.800 --> 0:14:30.600 then they suck up our blood. That's what they're feeding on. 0:14:31.040 --> 0:14:35.320 When they do this, they're sucking up several times their 0:14:35.440 --> 0:14:39.640 body weight in blood so that they can go several months, 0:14:39.680 --> 0:14:44.000 in fact, up to a year between blood meals. 0:14:44.760 --> 0:14:48.280 Erin, erin, I have read. I'm gonna pull up my 0:14:48.360 --> 0:14:50.800 notes real quick because I wrote this in a random 0:14:50.920 --> 0:14:57.160 spot and I have just written leeches live for eighteen 0:14:57.280 --> 0:15:00.720 to twenty seven years in the wild question. I'd love to. 0:15:00.680 --> 0:15:03.160 Say you wrote that, because I have How long does 0:15:03.200 --> 0:15:05.520 a leech live for? I still don't know. But they 0:15:05.520 --> 0:15:07.760 can fast for a year and a half. What the heck? 0:15:11.760 --> 0:15:13.000 That is amazing. 0:15:13.800 --> 0:15:16.080 Eighteen to twenty seven years. 0:15:16.160 --> 0:15:18.400 Yeah, and now I'm about to fact check myself because 0:15:18.400 --> 0:15:22.680 I want to make sure that that has a citation involved. Amazing, 0:15:24.080 --> 0:15:26.480 all right, So we did just do some fact checking. 0:15:26.560 --> 0:15:31.400 We fact checked because we couldn't resist. And years is 0:15:31.400 --> 0:15:34.400 definitely on a scale of years. Some sources say up 0:15:34.440 --> 0:15:36.480 to twenty years. I did find a couple sources that 0:15:36.560 --> 0:15:39.840 said that quoted the eighteen to twenty seven and a 0:15:39.880 --> 0:15:42.120 lot of them also say like two to eight, So 0:15:42.160 --> 0:15:44.000 it seems like there might be a range. But it 0:15:44.160 --> 0:15:49.360 seems like the maximum lifespan in a suitable environment could 0:15:49.400 --> 0:15:52.200 be upwards of twenty years, which is I mean, I 0:15:52.240 --> 0:15:55.560 never would have expected more than one year exactly. 0:15:55.680 --> 0:16:00.120 That's like anything beyond I'm sorry, it's a warm it's 0:16:00.160 --> 0:16:01.880 a worm. It's amazing. 0:16:02.120 --> 0:16:05.120 What's the longest lived worm? Do you think someone let 0:16:05.200 --> 0:16:07.600 us know, we're too. 0:16:07.480 --> 0:16:11.680 Many rabbit holes, too many, too many get back to leeches. 0:16:12.080 --> 0:16:14.840 They're sucking all this blood, a whole bunch so that 0:16:14.880 --> 0:16:18.480 they can live their years in between blood meals. So 0:16:18.880 --> 0:16:23.400 for this blood to not just coagulate on removal from 0:16:23.680 --> 0:16:26.640 the body, which is what blood wants to do. That's 0:16:26.640 --> 0:16:30.000 what it does when it removes from the body. Leeches 0:16:30.120 --> 0:16:33.720 have a whole bunch of compounds in their saliva that 0:16:33.840 --> 0:16:39.480 function as anticoagulants. The first, most important and most well 0:16:39.520 --> 0:16:42.680 known and well studied is called herod in. It's like 0:16:42.880 --> 0:16:46.840 named after the leeches, and this is pretty cool. It 0:16:46.960 --> 0:16:50.360 inhibits thrombin, which, if you want to throw all the 0:16:50.400 --> 0:16:53.520 way back to our hemophilia episode, we talked a lot 0:16:53.560 --> 0:16:58.120 in that episode about the cascade of reactions that happens 0:16:58.160 --> 0:17:00.880 in order for our blood to clot, one compound has 0:17:00.920 --> 0:17:03.640 to be activated, which activates another, and on and on 0:17:03.680 --> 0:17:07.080 and on. Thrombin is one of the final enzymes in 0:17:07.119 --> 0:17:11.040 this cascade, so that is what herod in is blocking. 0:17:11.119 --> 0:17:14.520 It's kind of like the bottom or top, depending on 0:17:14.560 --> 0:17:16.719 which way you want to look at it, of this cascade, 0:17:17.600 --> 0:17:21.680 and it's one of the major regulatory steps in coagulation, 0:17:21.840 --> 0:17:27.160 so it's a really effective way to block coagulation. Herod 0:17:27.200 --> 0:17:33.080 In was synthesized via recombinant DNA and it's used medicinally today. 0:17:33.240 --> 0:17:36.199 We use it all the time in medicine, especially if 0:17:36.240 --> 0:17:39.280 people can't use heparin, either because they've had a reaction 0:17:39.320 --> 0:17:41.480 to it or because they're allergic or for whatever reason. 0:17:42.760 --> 0:17:46.040 But that's not all I said. They have a hundred 0:17:46.160 --> 0:17:50.760 bioactive substances. They have a bunch of other substances that 0:17:50.800 --> 0:17:54.720 block other parts of the coagulation cascade, like factor ten a, 0:17:55.119 --> 0:17:58.879 et cetera. Blah blah blah. They also have a bunch 0:17:58.920 --> 0:18:06.240 of compounds that block platelets from aggregating allah aspirin, which 0:18:06.280 --> 0:18:10.080 means that they're stopping that first part of the coagulation 0:18:10.240 --> 0:18:12.679 because platelets are one of the first things. But what 0:18:12.720 --> 0:18:16.680 it also means in us is that our wounds from 0:18:16.720 --> 0:18:19.600 a leech are going to ooze for a long time 0:18:19.680 --> 0:18:22.080 because platelets are one of the first things that we 0:18:22.119 --> 0:18:26.000 would use to stop, and they injected that saliva into us, right. 0:18:27.160 --> 0:18:29.280 But that's not even all. They also have a whole 0:18:29.320 --> 0:18:33.520 bunch of other enzymes. Some of them serve to increase 0:18:33.600 --> 0:18:39.439 the permeability of our connective tissue, which for the leech 0:18:40.000 --> 0:18:43.600 allows for their secretions to penetrate more deeply into our 0:18:43.600 --> 0:18:48.040 tissues so that they work more Medicinally. What this can 0:18:48.080 --> 0:18:52.840 do is promote resorption of fluid and blood because it's 0:18:53.040 --> 0:18:58.359 increasing the permeability of the connective spaces. They also have 0:18:58.560 --> 0:19:01.320 enzymes that help to dissolve any blood clots that have 0:19:01.440 --> 0:19:05.600 already formed, and a lot of the things that they release, 0:19:05.880 --> 0:19:13.440 they're soesting much helps with vasodilation and reducing scar tissue formation. 0:19:13.680 --> 0:19:16.320 Like the list goes on, and we still don't know 0:19:16.680 --> 0:19:21.840 the mechanisms of every one of these compounds. There's also 0:19:21.920 --> 0:19:25.040 analgesic properties that we definitely don't understand, which makes the 0:19:25.160 --> 0:19:28.400 biting of those hundreds of leech teeth, or at least 0:19:28.440 --> 0:19:33.919 the sucking process a little bit less painful, perhaps, so 0:19:34.000 --> 0:19:37.119 you can imagine that with so many amazing things present 0:19:37.160 --> 0:19:41.359 in their saliva, leeches are used for a pretty wide 0:19:41.440 --> 0:19:45.000 variety of things, or I should say they've been studied 0:19:45.119 --> 0:19:49.560 for a pretty wide variety of things, because today they're 0:19:49.600 --> 0:19:54.520 most often used for post surgical care, especially in complicated 0:19:54.560 --> 0:19:57.480 procedures like what we heard in our first hand account 0:19:57.480 --> 0:20:02.360 with the reattachment of a finger, like skin flaps, reconstructions, 0:20:02.840 --> 0:20:05.760 places where you really don't want a lot of venous 0:20:05.920 --> 0:20:09.159 swelling or a lot of edema, like overall swelling in 0:20:09.200 --> 0:20:12.720 the tissue, because leeches are really good at reducing that 0:20:12.840 --> 0:20:17.560 kind of swelling, both by physically removing that venous blood 0:20:18.280 --> 0:20:22.840 but also by just reducing inflammation overall, and they leave 0:20:22.920 --> 0:20:25.960 these little wounds open to ooze for a few days, 0:20:26.000 --> 0:20:32.960 which can also be beneficial. But leeches have been evaluated 0:20:33.240 --> 0:20:37.040 for a lot of other things that I found fascinating 0:20:37.080 --> 0:20:39.840 and would never have expected people to use leeches for. 0:20:41.400 --> 0:20:44.560 The one that has the most evidence thus far is 0:20:44.600 --> 0:20:49.800 in the treatment of osteoarthritis. Of all things. Huh, yeah, 0:20:49.840 --> 0:20:55.040 that's my face too. So leeches have been studied for 0:20:55.119 --> 0:20:57.439 treatment of a lot of different kinds of arthritis, the 0:20:57.520 --> 0:21:02.280 idea being very similar that it's reducing inflammation around the joints, 0:21:02.320 --> 0:21:05.160 which is the cause of a lot of pain in arthritis, 0:21:05.840 --> 0:21:10.040 and a few larger meta analyzes seem to show some 0:21:10.160 --> 0:21:14.320 benefit in osteoorithritis at least for pain reduction and an 0:21:14.359 --> 0:21:18.240 increase in mobility. For other types of things like rheumatorid 0:21:18.320 --> 0:21:22.880 arthritis or even ankylosinkspondylitis, there's been at least like case studies, 0:21:23.040 --> 0:21:27.560 not necessarily large studies, but people have also tried to 0:21:27.640 --> 0:21:32.440 use leeches for things like migraines, TMJ, high blood pressure, 0:21:32.600 --> 0:21:36.879 heart disease, even some neurologic disorders, and at least the 0:21:37.040 --> 0:21:40.120 published studies on these seem to show benefit, but it's 0:21:40.160 --> 0:21:43.080 a really minimal amount of data. For any of these 0:21:43.119 --> 0:21:45.359 other conditions. You're not going to find people who are 0:21:45.359 --> 0:21:48.080 going to give you leeches for your blood pressure, like 0:21:48.119 --> 0:21:52.880 that's not a thing. But for reconstructive surgery, it absolutely 0:21:52.960 --> 0:21:57.320 is a thing. Yeah, and some people have used leeches 0:21:58.160 --> 0:22:01.240 for the treatment of chronic wounds, so you could use 0:22:01.320 --> 0:22:03.480 leeches and maggots together. 0:22:03.400 --> 0:22:11.760 In in combination. All that's amazing. I know that. That 0:22:11.920 --> 0:22:16.120 is leeches, you know, I love them. 0:22:16.640 --> 0:22:18.400 Their saliva is incredible. 0:22:18.480 --> 0:22:22.800 It's magic. Yeah, it's more powerful than magic. It's nature. 0:22:26.400 --> 0:22:29.639 So Aaron, tell me, yeah, tell me about the history 0:22:29.680 --> 0:22:32.840 of these little suckers, get it nice? 0:22:33.760 --> 0:22:33.879 Uh? 0:22:34.080 --> 0:22:37.880 Yeah, I can absolutely do that. Let's take a quick 0:22:37.880 --> 0:22:40.480 break and then I'll tell you as much as I 0:22:40.520 --> 0:23:11.600 can about leeches. All right, Before I get into the long, 0:23:12.000 --> 0:23:16.119 long history of leeches used in medicine, I wanted to 0:23:16.200 --> 0:23:18.520 first take a bit of time to just get to 0:23:18.680 --> 0:23:22.320 know this group of animals a little bit more broadly. Okay, 0:23:22.920 --> 0:23:27.520 so much fun. And estimated seven hundred species of leeches 0:23:27.720 --> 0:23:31.840 have been described, did you wow? Seven hundred? Yeah, and 0:23:31.880 --> 0:23:36.600 they can be found on all continents and seas except Antarctica. 0:23:36.760 --> 0:23:40.600 They live in caves, in saltwater, in fresh water, in 0:23:40.720 --> 0:23:44.920 hot water, in freezing water, in shallow water, in deep water. 0:23:45.160 --> 0:23:51.520 The record is over seventy eight hundred meters yep. I 0:23:51.600 --> 0:23:52.000 have to. 0:23:51.920 --> 0:23:54.800 Say these last two episodes are making me feel like 0:23:55.160 --> 0:23:59.120 I did all of my invertebrate zoology classes poorly by 0:23:59.440 --> 0:24:01.040 not remember any of this. 0:24:02.200 --> 0:24:05.800 Oh, if I once knew this, I have long forgotten it. 0:24:07.119 --> 0:24:11.520 Maybe I just never learned it. But like, okay, you. 0:24:11.640 --> 0:24:16.160 Keep going, please, okay, okay. They leeches also live in 0:24:16.320 --> 0:24:20.639 arsenic laced water, in super alkaline water, not in water 0:24:20.720 --> 0:24:25.440 at all, but on moist land. It's pretty rad Okay, 0:24:25.480 --> 0:24:28.399 a land leach, a land leech. And okay, if we 0:24:28.480 --> 0:24:31.480 say picture a leech, most of us are going to 0:24:31.560 --> 0:24:34.760 picture those leeches from stand by Me that we talked about, 0:24:34.880 --> 0:24:39.119 or something very similar. But did you know that only 0:24:39.160 --> 0:24:41.800 about half of leeches feed on blood? 0:24:43.040 --> 0:24:48.560 No? I thought most of them dead half half half? 0:24:49.520 --> 0:24:51.360 But are most of them still parasitic? 0:24:52.160 --> 0:24:52.360 Well? 0:24:52.400 --> 0:24:58.159 The other ones feed on things like earthworms, gastropods, crustaceans, 0:24:58.200 --> 0:25:00.240 and insect larvae like. 0:25:00.200 --> 0:25:03.800 As parasites more as like just cavor predators. 0:25:03.880 --> 0:25:10.520 Yeah. Yeah, one of the biggest leeches, reaching lengths of 0:25:11.040 --> 0:25:15.520 up to three hundred millimeters, which is nearly one foot 0:25:15.560 --> 0:25:20.200 eleven point eight inches. Uh, preys on worms. 0:25:20.960 --> 0:25:22.040 It eats other worms. 0:25:22.080 --> 0:25:25.800 It eats other worms. But the biggest leech, I'm going 0:25:25.840 --> 0:25:30.919 to try to pronounce this Hementaria GILLANII, gets up to 0:25:31.119 --> 0:25:36.480 four hundred and fifty millimeters long seventeen point seven inches erin. 0:25:36.680 --> 0:25:39.680 That is very large for a worm. 0:25:40.040 --> 0:25:43.960 Nearly four inches in width. And this guy does feed 0:25:44.000 --> 0:25:48.719 on blood. Who's blood, lots of different types of blood. 0:25:48.840 --> 0:25:54.720 So humans have been observed rabbits, cows, birds, Okay, but 0:25:54.920 --> 0:25:59.679 how do leeches find their prey, you might ask? They 0:25:59.760 --> 0:26:03.120 use many different sensory clues. As a matter of fact, 0:26:03.160 --> 0:26:07.560 So terrestrial leeches sense things like ground vibrations, whether the 0:26:07.760 --> 0:26:11.280 leaves and dirt or whatever they're laying in gets moved 0:26:11.359 --> 0:26:16.639 around or disturbed, shadows, air currents, and maybe, although it's 0:26:16.680 --> 0:26:20.480 been debated co two from the breath of their intended prey. 0:26:21.720 --> 0:26:25.439 Aquatic leeches use things like water currents or temperature or 0:26:25.480 --> 0:26:30.080 disturbance to detect prey. It's amazing and I have several more. 0:26:30.119 --> 0:26:32.080 If you don't mind me sharing a few more cool 0:26:32.080 --> 0:26:36.040 bits of leech trivia. Okay please. Leeches can live in 0:26:36.119 --> 0:26:39.720 extreme temperatures, not like the same leach or the same 0:26:39.800 --> 0:26:43.399 leech species, but for example, the freshwater leach. This is 0:26:43.480 --> 0:26:46.560 the names of these leeches. I'm telling you what challenging. 0:26:47.240 --> 0:26:53.840