1 00:00:01,000 --> 00:00:03,920 Speaker 1: Welcome to How Stuff Works. Now. I'm your host, Lauren Vogelbaum, 2 00:00:03,960 --> 00:00:10,680 Speaker 1: a researcher and writer. Here's how Stuff Works. Every week 3 00:00:10,720 --> 00:00:12,880 Speaker 1: I'm bringing you three stories from our team about the 4 00:00:12,920 --> 00:00:16,840 Speaker 1: weird and wondrous advances we've seen in science, technology, and culture, 5 00:00:17,280 --> 00:00:20,200 Speaker 1: except when I don't. This week, we've got just one 6 00:00:20,239 --> 00:00:23,040 Speaker 1: story for you, but it's a longer one, so don't worry. 7 00:00:23,079 --> 00:00:24,960 Speaker 1: If you're driving, you've still got about the same amount 8 00:00:25,000 --> 00:00:26,840 Speaker 1: of time before you have to fiddle with your phone again. 9 00:00:27,400 --> 00:00:30,120 Speaker 1: This one is from staff writer and editor Joe McCormick, 10 00:00:30,200 --> 00:00:33,720 Speaker 1: who's also the co host of a compatriot podcast of ours, 11 00:00:33,720 --> 00:00:37,040 Speaker 1: Stuff to Blow Your Mind. Joe wanted to know how 12 00:00:37,200 --> 00:00:40,920 Speaker 1: and what happens when a human swallows a leech, which 13 00:00:40,960 --> 00:00:43,040 Speaker 1: is a thing that happens more often than you'd like 14 00:00:43,120 --> 00:00:46,640 Speaker 1: to thank, which, to be fair, is more often than never. 15 00:00:47,400 --> 00:00:50,800 Speaker 1: So come along as Joe explores the historical and modern 16 00:00:50,880 --> 00:01:00,800 Speaker 1: cases of leech endo parasitism. Here's what happens when you 17 00:01:00,840 --> 00:01:06,319 Speaker 1: swallow a leech. In surgeon Lieutenant T. A. Granger of 18 00:01:06,360 --> 00:01:09,480 Speaker 1: the British Indian Army wrote a letter to the British 19 00:01:09,480 --> 00:01:13,680 Speaker 1: Medical Journal to report a stomach turning case of parasite 20 00:01:13,680 --> 00:01:29,480 Speaker 1: infestation he encountered at his colonial outpost. While working at 21 00:01:29,480 --> 00:01:32,800 Speaker 1: a fort in the Northwest Provinces of India, Granger received 22 00:01:32,800 --> 00:01:35,440 Speaker 1: a letter from an officer asking for his help with 23 00:01:35,480 --> 00:01:39,880 Speaker 1: an unusual medical complaint. According to the note, a local 24 00:01:39,959 --> 00:01:43,880 Speaker 1: man had a leech attached to the inside of his throat. 25 00:01:44,920 --> 00:01:48,400 Speaker 1: At first, Granger assumed it couldn't be true. Nevertheless, he 26 00:01:48,440 --> 00:01:52,040 Speaker 1: agreed to see the patient. The person he encountered was, 27 00:01:52,200 --> 00:01:56,080 Speaker 1: by Granger's account, an elderly pashtooned man with a gray beard. 28 00:01:56,760 --> 00:02:00,400 Speaker 1: When Granger came within sight, the old man immediately spat 29 00:02:00,440 --> 00:02:04,680 Speaker 1: out a heavy mouthful of thick, blackened blood, presumably to 30 00:02:04,720 --> 00:02:08,880 Speaker 1: demonstrate that his complaint was real. With the help of interpreters, 31 00:02:08,919 --> 00:02:12,519 Speaker 1: Granger questioned the man to learn about his condition. According 32 00:02:12,560 --> 00:02:16,079 Speaker 1: to his story, eleven days previous, the old man had 33 00:02:16,080 --> 00:02:18,880 Speaker 1: been drinking out of a rainwater tank when he suddenly 34 00:02:18,919 --> 00:02:22,200 Speaker 1: felt something catch in his throat. When he tried to 35 00:02:22,240 --> 00:02:25,800 Speaker 1: cough it up, he couldn't. Then the thing caught in 36 00:02:25,880 --> 00:02:29,880 Speaker 1: his throat began to move. He had difficulty swallowing and 37 00:02:29,919 --> 00:02:32,040 Speaker 1: felt like he was going to choke on the writhing 38 00:02:32,080 --> 00:02:35,120 Speaker 1: obstruction it caused him to vomit and to spit up 39 00:02:35,160 --> 00:02:39,919 Speaker 1: blood repeatedly. When Granger first looked inside the old man's throat, 40 00:02:40,000 --> 00:02:42,160 Speaker 1: he was able to remove a clot of blood, but 41 00:02:42,320 --> 00:02:45,600 Speaker 1: couldn't see any parasite. If it was there, it had 42 00:02:45,639 --> 00:02:49,000 Speaker 1: to be deeper. So the surgeon Lieutenant produced a pair 43 00:02:49,040 --> 00:02:54,080 Speaker 1: of polypus forceps, essentially very long tweezers with scissor handles, 44 00:02:54,160 --> 00:02:57,799 Speaker 1: and reached into the hidden depths of the man's lower farynx, 45 00:02:58,000 --> 00:03:01,840 Speaker 1: near the esophagus they are. He detected the presence of 46 00:03:01,840 --> 00:03:05,160 Speaker 1: an object, and through the metal of his instrument, Granger 47 00:03:05,280 --> 00:03:11,359 Speaker 1: could feel it moving. With the tips of the four steps, 48 00:03:11,360 --> 00:03:15,200 Speaker 1: he grabbed hold of the squirming object and with considerable force, 49 00:03:15,320 --> 00:03:19,160 Speaker 1: pulled it out. Indeed, it was a leech between two 50 00:03:19,200 --> 00:03:21,760 Speaker 1: point five and three inches or about six and a 51 00:03:21,840 --> 00:03:24,919 Speaker 1: half to seven and a half centimeters long, with a 52 00:03:25,000 --> 00:03:28,040 Speaker 1: body shaped like the three oh three inch ammunition the 53 00:03:28,080 --> 00:03:33,080 Speaker 1: British infantry used in their lee Metford rifles. A slimy, 54 00:03:33,080 --> 00:03:37,760 Speaker 1: writhing rifle cartridge engorged with human blood had been living 55 00:03:37,760 --> 00:03:42,120 Speaker 1: in this man's throat for eleven days. Granger's letter to 56 00:03:42,120 --> 00:03:44,560 Speaker 1: the b MJ doesn't go on to report what happened 57 00:03:44,560 --> 00:03:47,240 Speaker 1: to the old man, But after an experience like this, 58 00:03:47,320 --> 00:03:49,440 Speaker 1: one would at least hope the worst moment in the 59 00:03:49,480 --> 00:03:56,240 Speaker 1: man's life was behind him. When it comes to leeches 60 00:03:56,240 --> 00:03:59,520 Speaker 1: in the throat, Granger's report is not an isolated incident. 61 00:04:00,080 --> 00:04:03,200 Speaker 1: Granger himself heard stories of other cases like this in 62 00:04:03,280 --> 00:04:06,760 Speaker 1: neighboring towns, and this phenomenon is by no means limited 63 00:04:06,840 --> 00:04:10,320 Speaker 1: to nineteenth century India. Getting a leech attached to the 64 00:04:10,360 --> 00:04:12,960 Speaker 1: inside of a body cavity is common enough that there 65 00:04:12,960 --> 00:04:17,120 Speaker 1: are special medicalized terminologies for it, such as leech indo 66 00:04:17,200 --> 00:04:22,400 Speaker 1: parasitism or internal hierodoniasis. These are phrases most of us 67 00:04:22,400 --> 00:04:26,120 Speaker 1: would probably rather not have in our vocabulary, but even today, 68 00:04:26,240 --> 00:04:29,080 Speaker 1: in the twenty first century, people still show up at 69 00:04:29,120 --> 00:04:32,960 Speaker 1: hospitals around the world with leeches stuck inside their throats. 70 00:04:39,000 --> 00:04:43,919 Speaker 1: Strictly speaking, the leeches a worm phylum Analyta subclass heroudonea, 71 00:04:44,279 --> 00:04:47,479 Speaker 1: from which we get the word hierudoniasis, which refers to 72 00:04:47,520 --> 00:04:51,320 Speaker 1: the condition of being parasitized by a leech. Leeches have 73 00:04:51,480 --> 00:04:56,240 Speaker 1: segmented bodies imagine rings like an earthworm, and suckers at 74 00:04:56,279 --> 00:04:59,159 Speaker 1: both ends. One large sucker at the rear of the 75 00:04:59,200 --> 00:05:02,880 Speaker 1: body used crawling and leverage, and a smaller sucker at 76 00:05:02,920 --> 00:05:06,560 Speaker 1: the front containing the jaws and the mouth. Not all 77 00:05:06,640 --> 00:05:10,440 Speaker 1: leeches are blood drinkers. Some scavenge for detritus, some are 78 00:05:10,440 --> 00:05:13,359 Speaker 1: predatory hunters. But the leech we know best is that 79 00:05:13,480 --> 00:05:17,280 Speaker 1: vampiric parasite that clamps onto the larger host and steadily 80 00:05:17,360 --> 00:05:20,560 Speaker 1: drains all the blood it can, often until the leech's 81 00:05:20,600 --> 00:05:24,400 Speaker 1: body is swollen to around ten times its original size. 82 00:05:25,000 --> 00:05:28,920 Speaker 1: In the wild, leeches drink from all manner of hosts, mammals, fish, 83 00:05:29,000 --> 00:05:32,599 Speaker 1: and amphibians. When a leech bites, it makes a y 84 00:05:32,720 --> 00:05:36,400 Speaker 1: shaped incision in the skin with three curved jaws covered 85 00:05:36,440 --> 00:05:40,800 Speaker 1: in serrated teeth like tiny circular saws, and then extracts 86 00:05:40,800 --> 00:05:44,440 Speaker 1: blood with a muscular sucking action. The saliva of the 87 00:05:44,520 --> 00:05:47,040 Speaker 1: leech is known to contain a cocktail of chemicals to 88 00:05:47,120 --> 00:05:51,520 Speaker 1: ease the process, including heroudin, a polypeptide that prevents blood 89 00:05:51,520 --> 00:05:55,919 Speaker 1: from clotting. Leeches are classically known as external parasites, drawing 90 00:05:55,960 --> 00:05:58,480 Speaker 1: their liquid diet through the outer skin of the host, 91 00:05:58,600 --> 00:06:02,919 Speaker 1: but given the ratunity, they will feed from internal surfaces 92 00:06:02,960 --> 00:06:07,280 Speaker 1: as well, such as the nave of pharynx, larynx, vagina, bladder, 93 00:06:07,400 --> 00:06:11,880 Speaker 1: and anus. Humans have an unusual relationship with leeches that's 94 00:06:11,880 --> 00:06:15,320 Speaker 1: perhaps unique among all the world's parasites. The use of 95 00:06:15,400 --> 00:06:19,160 Speaker 1: leeches is pervasive throughout the history of medicine, even giving 96 00:06:19,200 --> 00:06:23,279 Speaker 1: the European medical leech harudo medicine alis its modern name. 97 00:06:24,120 --> 00:06:27,400 Speaker 1: In some historical periods, they were so commonly used as 98 00:06:27,480 --> 00:06:31,479 Speaker 1: instruments of blood letting that collecting wild leeches was a 99 00:06:31,560 --> 00:06:36,960 Speaker 1: solid money making operation. Rural leech gatherers would wage bare 100 00:06:37,080 --> 00:06:40,280 Speaker 1: legged through the scum of stagnant ponds, hoping when they 101 00:06:40,320 --> 00:06:43,240 Speaker 1: emerged on the other side to see patterns of glistening 102 00:06:43,320 --> 00:06:47,480 Speaker 1: green black anelids sucking from their ankles and calves. In 103 00:06:47,480 --> 00:06:51,280 Speaker 1: his eighteen oh seven poem Resolution and Independence, the English 104 00:06:51,400 --> 00:06:54,680 Speaker 1: romantic poet William Wordsworth writes about his encounter with this 105 00:06:54,800 --> 00:06:58,960 Speaker 1: brand of leech harvester quote. He told that to these 106 00:06:59,000 --> 00:07:02,280 Speaker 1: waters he had come to gather leeches, being old and poor, 107 00:07:02,839 --> 00:07:07,360 Speaker 1: employment hazardous and wearisome, and he had many hardships to endure. 108 00:07:07,800 --> 00:07:11,320 Speaker 1: From pond to pond, he roamed from more to more, 109 00:07:11,320 --> 00:07:15,160 Speaker 1: housing with God's good help by choice or chance, And 110 00:07:15,200 --> 00:07:20,000 Speaker 1: in this way he gained an honest maintenance. Assuming you 111 00:07:20,040 --> 00:07:23,320 Speaker 1: find the idea of being sucked by a leech somewhat disgusting, 112 00:07:23,640 --> 00:07:25,840 Speaker 1: and assuming you find the idea of being sucked by 113 00:07:25,840 --> 00:07:29,080 Speaker 1: a leech on the inside of your body even more disgusting, 114 00:07:29,600 --> 00:07:31,760 Speaker 1: you might find it odd that the human taste for 115 00:07:31,840 --> 00:07:36,440 Speaker 1: therapeutic parasitism doesn't stop at the outer skin. During the 116 00:07:36,520 --> 00:07:40,560 Speaker 1: leech craze, leaching enthusiasts open many of their bodily orifices 117 00:07:40,600 --> 00:07:43,800 Speaker 1: and internal cavities to the prized worms with the help 118 00:07:43,840 --> 00:07:47,680 Speaker 1: of some ingenious medical technology. In a two thousand eleven 119 00:07:47,760 --> 00:07:51,160 Speaker 1: article on the technological history of leeching, Robert G. W. 120 00:07:51,400 --> 00:07:54,680 Speaker 1: Kirk and Neil Pemberton right that quote. The opening of 121 00:07:54,720 --> 00:07:58,560 Speaker 1: the interior of the body often required the physical alteration 122 00:07:58,760 --> 00:08:01,880 Speaker 1: of the leech, for example, the attachment of thread to 123 00:08:01,920 --> 00:08:05,240 Speaker 1: prevent the loss of the leech within, or the supplementation 124 00:08:05,320 --> 00:08:08,280 Speaker 1: of the leech with mechanical tools to enable the passage 125 00:08:08,280 --> 00:08:11,320 Speaker 1: of the creature into locations such as the anus, where 126 00:08:11,320 --> 00:08:15,360 Speaker 1: it was now recommended as a means to treat problematic prostates. 127 00:08:16,440 --> 00:08:18,600 Speaker 1: There are even a few limited ways in which leeches 128 00:08:18,640 --> 00:08:21,920 Speaker 1: have proven useful, though perhaps still controversial, in the science 129 00:08:21,960 --> 00:08:25,440 Speaker 1: based medicine of recent decades, such as to ensure veins 130 00:08:25,480 --> 00:08:29,640 Speaker 1: are working properly and aren't overfilled or distending after microsurgery. 131 00:08:30,760 --> 00:08:33,720 Speaker 1: Here and there, you can still encounter reports in medical 132 00:08:33,800 --> 00:08:39,960 Speaker 1: journals of rare cases of accidental internal hyerdoniasis, including leeches 133 00:08:40,280 --> 00:08:43,440 Speaker 1: in the throat. In two thousand two, a group of 134 00:08:43,480 --> 00:08:47,240 Speaker 1: doctors reported in the journal Pediatric Pulmonology the case of 135 00:08:47,240 --> 00:08:49,520 Speaker 1: a six year old boy in Syria who was brought 136 00:08:49,520 --> 00:08:52,920 Speaker 1: to the emergency room because he couldn't breathe. His mother 137 00:08:52,960 --> 00:08:55,400 Speaker 1: reported that he had been coughing up blood and that 138 00:08:55,480 --> 00:08:58,240 Speaker 1: a month ago a village doctor had diagnosed the boy 139 00:08:58,280 --> 00:09:02,679 Speaker 1: with asthma and prescribed court steroids and broncho dilators. This 140 00:09:02,800 --> 00:09:07,440 Speaker 1: turned out to be a misdiagnosis. The doctors were able 141 00:09:07,480 --> 00:09:10,800 Speaker 1: to remove a seven centimeter or nearly three inch leach 142 00:09:10,960 --> 00:09:14,560 Speaker 1: from the boy's airway through surgery, and subsequently discovered that 143 00:09:14,600 --> 00:09:17,600 Speaker 1: the child had been drinking from a leech infested stream 144 00:09:17,679 --> 00:09:21,280 Speaker 1: in rural northern Syria. After the leech was removed, the 145 00:09:21,320 --> 00:09:26,120 Speaker 1: boy's symptoms disappeared. In two thousand nine, another group reported 146 00:09:26,120 --> 00:09:28,720 Speaker 1: in the European Journal of Pediatrics the case of an 147 00:09:28,720 --> 00:09:31,880 Speaker 1: eleven year old boy in central Iran who presented it 148 00:09:31,920 --> 00:09:34,800 Speaker 1: a rural healthcare center with blood in his mouth and 149 00:09:34,880 --> 00:09:37,880 Speaker 1: a sore throat that had lasted for two weeks. The 150 00:09:37,920 --> 00:09:40,400 Speaker 1: boy had been given antibiotics for his sore throat and 151 00:09:40,440 --> 00:09:44,360 Speaker 1: the problem did not respond. Inspection of his mouth revealed 152 00:09:44,360 --> 00:09:48,600 Speaker 1: a black circular blob about two centimeters by three centimeters 153 00:09:48,720 --> 00:09:51,840 Speaker 1: or about point eight by one point two inches, stuck 154 00:09:51,880 --> 00:09:54,400 Speaker 1: to the back of his throat, with blood oozing all 155 00:09:54,480 --> 00:09:59,080 Speaker 1: around it. Doctors applied litacaine spray, a topical pain killer, 156 00:09:59,440 --> 00:10:02,880 Speaker 1: and then pull the leech out with blunt forceps. Questioning 157 00:10:02,880 --> 00:10:05,040 Speaker 1: revealed the boy had been swimming in a lake near 158 00:10:05,040 --> 00:10:08,520 Speaker 1: his village. After the leech was removed, blood continued to 159 00:10:08,559 --> 00:10:10,600 Speaker 1: ooze out of the wound for about an hour, but 160 00:10:10,679 --> 00:10:14,880 Speaker 1: otherwise the boy was all right. In a doctor named 161 00:10:14,960 --> 00:10:18,880 Speaker 1: Demeckey McConnon published an article in the Ethiopian Journal of 162 00:10:18,920 --> 00:10:21,560 Speaker 1: Health Science relaying the case of a seven year old 163 00:10:21,559 --> 00:10:24,720 Speaker 1: boy in Ethiopia who presented with blood stained saliva and 164 00:10:24,800 --> 00:10:27,880 Speaker 1: shortness of breath at his home. Someone had tried to 165 00:10:27,920 --> 00:10:30,880 Speaker 1: treat him with a traditional medicine made of tobacco leaves 166 00:10:30,880 --> 00:10:34,640 Speaker 1: and flax seed to no effect. In the report, McConnon 167 00:10:34,760 --> 00:10:37,839 Speaker 1: indicates that the boy had contact with an unprotected source 168 00:10:37,880 --> 00:10:41,160 Speaker 1: of spring water that was also used for watering animals. 169 00:10:41,640 --> 00:10:44,680 Speaker 1: Luring scopy showed some kind of foreign body at the 170 00:10:44,679 --> 00:10:47,520 Speaker 1: top of the trachea. The child was put under general 171 00:10:47,559 --> 00:10:52,160 Speaker 1: anesthesia and the leech was removed with forceps. After the extraction, 172 00:10:52,200 --> 00:10:55,680 Speaker 1: the boy seemed to have a full recovery. Laryngeal and 173 00:10:55,720 --> 00:10:59,840 Speaker 1: pharyngeal leech infestations are rare these days, especially in developed 174 00:11:00,000 --> 00:11:03,600 Speaker 1: countries with access to clean water, but it can still happen. 175 00:11:04,040 --> 00:11:07,600 Speaker 1: Possible symptoms of a leech in the throat are difficulty swallowing, 176 00:11:08,000 --> 00:11:12,560 Speaker 1: sore throat, vomiting blood, coughing up blood, a sense of 177 00:11:12,640 --> 00:11:16,480 Speaker 1: having a foreign body in the throat melna meaning dark 178 00:11:16,559 --> 00:11:20,240 Speaker 1: sticky feces indicating the swallowing of blood, a feeling of 179 00:11:20,280 --> 00:11:24,439 Speaker 1: suffocation or shortness of breath, and harsh or raspy breathing. 180 00:11:25,280 --> 00:11:26,920 Speaker 1: If you think you've got a leech in your throat 181 00:11:27,000 --> 00:11:29,600 Speaker 1: right now, don't panic. Just see a doctor as soon 182 00:11:29,640 --> 00:11:31,920 Speaker 1: as you can, as you may have gathered from the 183 00:11:31,920 --> 00:11:35,800 Speaker 1: cases we just mentioned, pharyngeal or even laryngeal harrod niasis 184 00:11:35,920 --> 00:11:38,520 Speaker 1: is not necessarily a death sentence, though it can be 185 00:11:38,600 --> 00:11:41,800 Speaker 1: dangerous if the parasite obstructs any part of the airway. 186 00:11:42,200 --> 00:11:44,199 Speaker 1: If the doctor knows what to look for and has 187 00:11:44,240 --> 00:11:47,080 Speaker 1: a pair of blunt forceteps on hand, chances are good 188 00:11:47,120 --> 00:11:49,360 Speaker 1: that you'll be all right. But of course the best 189 00:11:49,360 --> 00:11:53,080 Speaker 1: case scenario is to avoid the problem entirely, So don't 190 00:11:53,120 --> 00:11:55,720 Speaker 1: drink dirty water and don't swim in the water where 191 00:11:55,720 --> 00:12:01,760 Speaker 1: the leeches slim. That's our show for this week. Thank 192 00:12:01,800 --> 00:12:03,920 Speaker 1: you so much for tuning in. Further thanks to our 193 00:12:03,920 --> 00:12:07,680 Speaker 1: audio producer Dylan Fagin and our editorial liaison Alison Laddermilk. 194 00:12:07,920 --> 00:12:10,520 Speaker 1: Subscribe to now Now for more of the lated science 195 00:12:10,559 --> 00:12:12,440 Speaker 1: news and sends links to anything you'd like to hear 196 00:12:12,520 --> 00:12:15,560 Speaker 1: us cover, plus a tattoo artist whose work you dig. 197 00:12:15,920 --> 00:12:17,800 Speaker 1: As always, you can send us an email at now 198 00:12:17,880 --> 00:12:20,960 Speaker 1: podcast at how stuff works dot com, and for lots 199 00:12:21,000 --> 00:12:23,200 Speaker 1: more stories like these, head on over to our home 200 00:12:23,240 --> 00:12:39,080 Speaker 1: planet now dot how stuff works dot com.