WEBVTT - Ep 39 Toxoplasmosis: Calling All Cats 0:00:00.680 --> 0:00:04.640 I contracted toxoplasmosis in my first trimester. I will never 0:00:04.720 --> 0:00:07.560 know how the doctor did not educate me or test 0:00:07.600 --> 0:00:10.200 me for it. I was not given the opportunity to 0:00:10.200 --> 0:00:13.160 prevent the devastation this disease would have on my baby. 0:00:13.760 --> 0:00:15.720 It had a lot of time to go unchecked and 0:00:15.760 --> 0:00:18.599 do a lot of damage. My daughter, Dana, was born 0:00:18.720 --> 0:00:21.279 six weeks premature with severe damage to her brain and 0:00:21.320 --> 0:00:24.560 her eyes. She is now twenty two years old. She 0:00:24.640 --> 0:00:27.800 has very little cortex to her brain, She has cerebral palsy, 0:00:28.280 --> 0:00:32.599 She is blind. She has severe developmental delays. Dana requires 0:00:32.640 --> 0:00:37.559 our full care. She cannot sit unassisted, walk, talk, feed herself, 0:00:37.640 --> 0:00:40.960 dress herself, or toilet herself. My husband and I still 0:00:41.000 --> 0:00:43.599 change her diapers day and night. The toll on her 0:00:43.600 --> 0:00:46.680 body has been tremendous. She has had ten surgeries, two 0:00:46.760 --> 0:00:49.640 of which were so traumatic we almost lost her. She 0:00:49.720 --> 0:00:52.040 has a tube that drains excess fluid from her brain. 0:00:52.760 --> 0:00:54.560 She has a metal rod in her back to help 0:00:54.560 --> 0:00:57.560 straighten severe curvature of her spine so her organs and 0:00:57.640 --> 0:01:00.920 lungs can continue to function. She has a pump surgically 0:01:00.920 --> 0:01:03.440 inserted to give her constant doses of a medicine to 0:01:03.480 --> 0:01:06.959 help her relax her muscles from further contorting her body, which, 0:01:07.040 --> 0:01:10.880 by the way, is only minimally successful. One hip was reconstructed, 0:01:10.920 --> 0:01:14.679 the other is currently dislocated. I hate what toxoplasmosis has 0:01:14.760 --> 0:01:17.039 done to my daughter. It has stolen the dreams I 0:01:17.040 --> 0:01:19.679 once had for her and from me. Our whole family 0:01:19.680 --> 0:01:23.200 has experienced emotional and financial strain. Yet through this all 0:01:23.240 --> 0:01:26.000 we have loved this young lady. She is remarkably determined 0:01:26.040 --> 0:01:28.880 to endure. She laughs. She enjoys being a part of 0:01:28.920 --> 0:01:32.520 an active family life. Dana has a younger sister, Rebecca, 0:01:32.560 --> 0:01:34.760 who is in college right now. She is one of 0:01:34.760 --> 0:01:38.160 the smartest, wittiest, kindest people I know. Life has been 0:01:38.160 --> 0:01:41.360 difficult for her too. Watching Rebecca, I can't help but 0:01:41.480 --> 0:01:43.520 think of what Dana's life would have been like if 0:01:43.520 --> 0:01:46.360 her infection were caught early on. What would her future 0:01:46.440 --> 0:02:33.520 have held? Oh my god. Yeah. That was an account 0:02:33.520 --> 0:02:37.680 by Janet Morel, who testified before the Illinois State Senate 0:02:38.160 --> 0:02:41.760 in support of Senate Bill three six sixty seven, which 0:02:42.240 --> 0:02:46.040 was the proposed Prenatal and Neonatal Congenital Toxic Plasmosis Prevention 0:02:46.120 --> 0:02:50.400 and Treatment Act Act. This bill would provide that healthcare 0:02:50.440 --> 0:02:54.520 professionals shall provide counseling for toxic plasmosis and testing for 0:02:54.600 --> 0:02:58.440 toxoplasma gandhiaye when providing care to a pregnant woman during 0:02:58.480 --> 0:03:01.919 her pregnancy. So that was part of her testimony. 0:03:02.240 --> 0:03:04.880 Wow, h my god. 0:03:05.520 --> 0:03:08.400 Yeah, it's a really it's really sad. It's very rough. 0:03:09.160 --> 0:03:09.440 Rough. 0:03:10.080 --> 0:03:12.079 Well, I'm Aaron. 0:03:11.919 --> 0:03:14.880 Welsh and I'm Aaron Olman Updyke and. 0:03:14.720 --> 0:03:18.080 This is this podcast will Kill You. This week we 0:03:18.280 --> 0:03:22.440 are covering toxoplasma gandhi I. Yeah, we are, which has 0:03:22.480 --> 0:03:26.320 been a pretty heavily requested episode. I think has it, Yeah, 0:03:26.400 --> 0:03:30.239 I think it has Yeah, And it's going to be 0:03:30.320 --> 0:03:32.440 a heavy one. It's going to be an interesting one. 0:03:32.600 --> 0:03:34.560 It's going to be all the things that you've come 0:03:34.600 --> 0:03:40.800 to expect from this podcast. Yeah, speaking of things to expect. 0:03:40.720 --> 0:03:41.960 It's quarantine ey time. 0:03:42.720 --> 0:03:44.800 It is erin. 0:03:44.880 --> 0:03:46.160 What are we drinking this week? 0:03:46.400 --> 0:03:52.880 This week we're drinking what the cat dragged in? What 0:03:53.080 --> 0:03:55.520 is in what the cat dragged in? Well, of course 0:03:55.760 --> 0:03:59.400 it's not a dead mouse, but that would be appropriate 0:03:59.440 --> 0:04:05.320 as well. It's vodka, some sparkling wine, a little Creme 0:04:05.400 --> 0:04:07.520 de violette and lemon juice. 0:04:07.840 --> 0:04:12.040 Yeah, it's tasty. It's the big crucial thing. Crucial is 0:04:12.120 --> 0:04:15.360 that you rim the glass with pop rocks. 0:04:15.080 --> 0:04:17.920 Of course, because they look just like kitty litter. 0:04:19.279 --> 0:04:19.839 There you go. 0:04:21.400 --> 0:04:22.080 We'll post the. 0:04:22.040 --> 0:04:24.600 Full recipe for this quarantini as well as our non 0:04:24.640 --> 0:04:28.040 alcoholic plusy Burta on our website This podcast will Kill 0:04:28.080 --> 0:04:30.320 You dot Com and all of our social media channels, 0:04:30.320 --> 0:04:32.720 so follow us there for the full recipe. 0:04:32.880 --> 0:04:35.320 And I think I want to cover a couple pieces 0:04:35.360 --> 0:04:37.440 of business which I just don't think that we have 0:04:37.600 --> 0:04:42.799 done it all pertains to live shows or live ish shows. 0:04:43.080 --> 0:04:45.120 They weren't live ish like we were there. 0:04:45.760 --> 0:04:50.520 Yeah, that's true. It wasn't like a full live show. 0:04:50.720 --> 0:04:52.839 We're not going on tour or anything like that. But 0:04:53.279 --> 0:04:56.400 we were lucky enough to go to both the University 0:04:56.440 --> 0:04:59.760 of Florida thanks to Nick Kaiser, and also to the 0:05:00.040 --> 0:05:04.200 University of Michigan thanks to Laura Haynes. Yeah, we met 0:05:04.320 --> 0:05:07.760 so many amazing people during both trips. It was really, 0:05:07.800 --> 0:05:08.360 really fun. 0:05:08.440 --> 0:05:10.679 We had the most fun at both of those trips. 0:05:10.720 --> 0:05:13.000 It was super excellent. So thank you for inviting us, 0:05:13.000 --> 0:05:14.720 and thanks to everyone who came and watched. 0:05:14.760 --> 0:05:15.559 It was so fun. 0:05:16.040 --> 0:05:20.719 It was great. And also I recently, Aaron Welsh, I 0:05:21.040 --> 0:05:25.000 was recently a guest on a live show of a 0:05:25.040 --> 0:05:28.159 podcast called The Road to Now. Yeah. Yeah, it was 0:05:28.160 --> 0:05:30.840 super fun. So this is a really great history podcast 0:05:31.320 --> 0:05:33.599 and they came to Chicago recently and I got to 0:05:33.640 --> 0:05:37.120 be a guest along with Obama's White House photographer Pete Susa. 0:05:37.320 --> 0:05:42.880 So it's so great, mind blowing, so cool, surreal. But anyway, 0:05:42.920 --> 0:05:46.360 you can hear that episode of the live show on 0:05:46.440 --> 0:05:48.480 the Road to Now, So just look them up wherever 0:05:48.480 --> 0:05:50.479 you get your podcasts. And we're also going to post 0:05:50.480 --> 0:05:52.680 a link if we haven't already by the time this 0:05:52.720 --> 0:05:54.080 comes out on our social media. 0:05:54.320 --> 0:05:56.120 Yes, any other business. 0:05:56.279 --> 0:06:00.760 We have a new merch including water bottle. 0:06:01.040 --> 0:06:02.480 Yes, they're gorgeous. 0:06:02.560 --> 0:06:05.520 They're very very cool, and they're the nice like insulated 0:06:05.640 --> 0:06:12.000 kind metal water bottles and fancy smelling soap new smells. 0:06:11.480 --> 0:06:13.360 Of soap new smells. 0:06:13.600 --> 0:06:14.520 So check that out. 0:06:14.880 --> 0:06:16.680 Just go to our website This podcast will kill You 0:06:16.720 --> 0:06:19.720 dot com and click on merch to find that. 0:06:22.000 --> 0:06:26.480 Any other business, Nope, let's just dive right in. Okay, Aaron, 0:06:26.720 --> 0:06:30.359 tell me about the biology of toxic plasmosis. I just 0:06:30.480 --> 0:06:33.080 can't wait to do that we'll take a little break, 0:06:52.920 --> 0:06:59.800 all right. Toxo Plasma gandhii toxic plasmosis. I've been looking 0:06:59.839 --> 0:07:03.800 for to doing this episode ever since I was a 0:07:03.839 --> 0:07:04.400 guest on. 0:07:04.480 --> 0:07:07.160 The per Cast. Oh yeah, yep. 0:07:07.560 --> 0:07:10.520 We talked a little bit about TOSO on that episode. 0:07:10.560 --> 0:07:13.800 If you haven't heard it, it's really fun. But I 0:07:14.000 --> 0:07:17.400 didn't do any research on TOCSO before I went on 0:07:17.440 --> 0:07:19.960 the Percast, so I felt really silly because I didn't 0:07:20.000 --> 0:07:22.600 know the answers to a lot of questions. So I'm 0:07:22.640 --> 0:07:28.320 excited to finally, you know, have done some research on this, like, 0:07:28.480 --> 0:07:31.360 actually know what I'm talking about a little bit. It's 0:07:31.400 --> 0:07:37.440 still not an expert, okay, so polished amateur exactly. 0:07:37.760 --> 0:07:40.320 That's a good description for like my life, I think. 0:07:43.120 --> 0:07:48.680 Okay, So, Toxoplasma gandhii is a protozoan parasite, so like 0:07:48.880 --> 0:07:52.000 malaria or giardiam. 0:07:53.000 --> 0:07:54.800 Oh you did a great job, thank you? 0:07:55.720 --> 0:07:58.000 Is that condescending it up just a little? 0:07:59.240 --> 0:07:59.400 So? 0:07:59.600 --> 0:08:04.160 This is a single celled organism that's not a bacteria 0:08:04.360 --> 0:08:10.800 or a virus. Okay, yeph And this, when I learned 0:08:10.880 --> 0:08:14.320 this fact, blew my mind so hard that even though 0:08:14.360 --> 0:08:16.880 this is technically EPI I'm gonna say. 0:08:16.640 --> 0:08:17.280 This up top. 0:08:17.760 --> 0:08:22.440 Toxo infects up to one third of the entire world's population. 0:08:23.160 --> 0:08:27.720 Uh huh, one third of the globe of humans. 0:08:28.080 --> 0:08:30.520 Uh huh. I know, I know. 0:08:31.800 --> 0:08:38.920 That is just mind wild, it's so wild, Oh my gracious. Okay, So, 0:08:39.360 --> 0:08:41.720 because this is a parasite, we have to talk about 0:08:41.720 --> 0:08:47.480 its life cycle because it's more complicated than some other organisms. Okay, So, 0:08:48.040 --> 0:08:53.239 the main host of Toxoplasma gandhi is of course cats. 0:08:53.880 --> 0:08:59.760 Cats are the definitive host of Toxoplasma GANDHII, and when 0:08:59.760 --> 0:09:06.480 they get infected with this parasite, they poop out thousands 0:09:07.160 --> 0:09:12.760 and thousands of something called oocysts. That's the life stage 0:09:12.800 --> 0:09:14.400 that the cats poop out. 0:09:15.040 --> 0:09:16.280 Okay, yep. 0:09:16.920 --> 0:09:21.080 And after one to five days in the environment the 0:09:21.160 --> 0:09:25.000 environment being cat poop, so cat box or your sandbox 0:09:25.000 --> 0:09:28.439 where your kids are playing, or your backyard or pretty 0:09:28.520 --> 0:09:30.640 much anywhere in the environment. 0:09:31.120 --> 0:09:33.120 These oocysts spoulate. 0:09:33.679 --> 0:09:37.280 So then they kind of become infectious at that point. 0:09:38.160 --> 0:09:44.560 Once they spoulate, they can persist alive and infectious in 0:09:44.640 --> 0:09:51.120 the environment for years, really years, well at least a year, okay, 0:09:51.160 --> 0:09:56.360 for year, yeah, for months and year, depending on the environment, 0:09:56.520 --> 0:09:59.240 so they can get into the soil, they can get 0:09:59.240 --> 0:10:02.760 into the water, they can get on your vegetables, et cetera. 0:10:03.400 --> 0:10:05.199 What's the ideal environment. 0:10:05.640 --> 0:10:09.720 The ideal environment would be kind of subtropical, so not 0:10:09.840 --> 0:10:13.400 too hot, not too cold, although they can survive freezing, 0:10:14.240 --> 0:10:20.199 you know, no big deal. Yeah, but they do. They 0:10:20.480 --> 0:10:23.000 like we'll see in the episection burdens tend to be 0:10:23.120 --> 0:10:26.200 highest in warmer climates because they do persist better in 0:10:26.240 --> 0:10:30.440 warmer climates. Okay, So they get all up in the 0:10:30.520 --> 0:10:35.880 environment and then they're picked up by small animals, birds, mice, rats, 0:10:36.679 --> 0:10:38.880 generally things that cats. 0:10:38.679 --> 0:10:40.160 Might like to feed on. 0:10:40.160 --> 0:10:43.840 Once they get into these small animals, they are now 0:10:43.920 --> 0:10:47.560 called taki zo whites. So that's the life stage that 0:10:47.720 --> 0:10:50.199 infects small animals. 0:10:50.440 --> 0:10:53.160 Okay, I want to make some sort of joke about 0:10:53.200 --> 0:10:54.760 taki but I tried. 0:10:55.200 --> 0:10:57.319 I tried too. There's no good one. 0:10:57.520 --> 0:11:02.320 So inside of a mouse, generally, the way that a 0:11:02.320 --> 0:11:05.920 small animal gets infected is by coming into contact with 0:11:06.000 --> 0:11:08.839 their mouth. So they eat some soil, they drink some water, 0:11:08.920 --> 0:11:10.920 they eat a piece of lettuce, whatever it is that 0:11:11.080 --> 0:11:15.800 has these tachisoites on them, and they get infected. Then 0:11:15.920 --> 0:11:20.000 these tachizoites burst out of the intestine of these mice 0:11:20.160 --> 0:11:24.559 or these rats, and they infect tons of different cells. 0:11:25.000 --> 0:11:27.520 So this is a parasite that is actually it has 0:11:27.559 --> 0:11:32.559 to be intracellular, so it invades cells inside of everything 0:11:32.840 --> 0:11:39.319 that it infects. And these this life stage replicates asexually, 0:11:39.400 --> 0:11:42.880 so it just divides, and it does so really really 0:11:42.960 --> 0:11:47.800 rapidly and really profusely. So in the mouse, you've now 0:11:47.840 --> 0:11:54.359 got this parasite dividing and replicating and swarming through the tissues. 0:11:55.200 --> 0:11:58.520 Then they'll find their way into two specific tissues that 0:11:58.520 --> 0:12:01.760 they like to invade, muscle and brain. 0:12:03.040 --> 0:12:05.360 Why do they like those two types of tissues? 0:12:05.520 --> 0:12:06.800 Well, let's talk about it. 0:12:08.520 --> 0:12:10.560 I like, how now you like you know me so 0:12:10.640 --> 0:12:13.600 well that you know what I'm going to ask pretty soon. 0:12:13.480 --> 0:12:16.360 Most of the time doesn't mean I always know the answers, though, 0:12:17.760 --> 0:12:20.200 but here we can talk about it. So they find 0:12:20.200 --> 0:12:23.840 their way into neural tissue and muscle tissue. Once they're there, 0:12:23.920 --> 0:12:25.679 I'm going to first say what they do once they're there, 0:12:25.720 --> 0:12:28.120 Then we'll talk about why these are the tissues they invade. 0:12:28.320 --> 0:12:32.000 Once they're there, they insist, so they actually transform into 0:12:32.200 --> 0:12:33.560 yet another life stage. 0:12:33.640 --> 0:12:35.040 The Brady zoite. 0:12:35.400 --> 0:12:40.120 The brady zoite forms a cyst inside of the muscle 0:12:40.160 --> 0:12:44.480 tissue or the brain tissue. The cyst is surrounded by 0:12:44.559 --> 0:12:49.240 the animal's tissue muscle or brain, but then full of 0:12:49.440 --> 0:12:53.480 hundreds of these brady zoites. These continue to divide, but 0:12:53.520 --> 0:12:58.560 they do so much more slowly. Okay, okay, But then 0:12:58.720 --> 0:13:01.920 to complete the life side, these brady zo whites have 0:13:01.960 --> 0:13:02.640 to find their. 0:13:02.480 --> 0:13:03.800 Way into a cat. 0:13:04.360 --> 0:13:08.760 Right, so the cat is going to eat the mouse 0:13:09.360 --> 0:13:12.320 or the rat or the bird. What part of the 0:13:12.360 --> 0:13:15.199 mouse or the rat or the bird. Do cats definitely 0:13:15.240 --> 0:13:16.720 eat muscle tissue? 0:13:17.120 --> 0:13:17.839 That makes sense? 0:13:17.920 --> 0:13:20.720 Okay, So that's why they insist in the muscle tissue. 0:13:21.200 --> 0:13:23.520 Why might they insist in the brain? 0:13:24.480 --> 0:13:26.360 Oh? I think I know the answer to this. 0:13:26.440 --> 0:13:27.240 Oh yeah. 0:13:27.480 --> 0:13:32.880 It turns out that Toxoplasmagondhia is a parasite that can 0:13:32.960 --> 0:13:38.360 exhibit behavior modification. So that means that it can actually 0:13:38.600 --> 0:13:43.200 change the behavior of the animals that it infects, which 0:13:43.280 --> 0:13:45.600 is it's really cool. 0:13:46.040 --> 0:13:47.200 It is very cool. 0:13:49.000 --> 0:13:52.280 It's kind of like blows the lid off of the 0:13:52.320 --> 0:13:57.320 whole parasite host dynamic in a way that is so 0:13:57.559 --> 0:14:00.400 sci fi. But also I think it's just a tip 0:14:00.440 --> 0:14:05.240 of the iceberg. Okay, I'm jumping the gun to it. 0:14:05.559 --> 0:14:07.920 It is so sci fi, but it's something that's actually 0:14:07.960 --> 0:14:12.000 not that uncommon in parasites that are transmitted what we 0:14:12.080 --> 0:14:15.440 call trophic lely, so from one what we call trophic 0:14:15.520 --> 0:14:18.760 level to another. So if you think of like the 0:14:18.800 --> 0:14:22.080 pyramid of life with like carnivores on the top, carnivores 0:14:22.080 --> 0:14:25.960 are gonna eat herbivores, and herbivores are gonna eat lettuce. 0:14:25.720 --> 0:14:30.000 Or whatever, right, primary produce, secondary producers, primary producers. 0:14:29.600 --> 0:14:36.800 Exactly right, right, yea lettuce, and so in in parasites 0:14:36.800 --> 0:14:39.440 that are transmitted like through the food chain like that, 0:14:39.640 --> 0:14:43.880 it's actually not that uncommon for parasites to manipulate the 0:14:43.920 --> 0:14:48.160 behavior of that intermediate host like the mouse, so that 0:14:48.240 --> 0:14:52.520 they're more likely to be eaten by the definitive host, 0:14:52.880 --> 0:14:53.280 i e. 0:14:53.680 --> 0:14:54.160 The cat. 0:14:54.720 --> 0:14:57.520 In the case of mice and rats that get infected, 0:14:57.520 --> 0:15:00.920 what they do is not only do they seek out 0:15:01.280 --> 0:15:07.880 more rapidly novel environments, and they're less fearful and more 0:15:08.000 --> 0:15:10.840 likely to be in open areas where normally mice and 0:15:10.920 --> 0:15:13.520 rats are kind of like they stay hidden because they 0:15:13.520 --> 0:15:18.720 don't want to be eaten, for example, So infected mice 0:15:19.080 --> 0:15:23.360 and rats will seek out novel areas and explore more readidly. 0:15:24.160 --> 0:15:27.360 And they have done studies that show that they're not 0:15:27.520 --> 0:15:32.400 only less afraid of cat smells like cat urine, they're 0:15:32.480 --> 0:15:36.400 actually attracted to smells like cat urine. 0:15:37.080 --> 0:15:44.520 Yeah, isn't that Oh, it's really Yeah, it's it's almost unbelievable, Like. 0:15:44.640 --> 0:15:48.160 When you think about that the parasite has evolved to 0:15:48.240 --> 0:15:51.880 be transmitted this way, and this is how, and so 0:15:52.240 --> 0:15:56.880 here's the reason why this happens, or a reason why 0:15:56.920 --> 0:16:02.920 this happens, is that only in cats can Toxoplasma GANDHII 0:16:03.120 --> 0:16:06.720 complete its life cycle because once a cat eats those 0:16:06.760 --> 0:16:09.480 brady zoites that are in the brain or muscle tissue 0:16:09.960 --> 0:16:15.000 inside the cat, they actually undergo sexual replication. And only 0:16:15.080 --> 0:16:20.480 in cats do does Toxoplasma gandhi actually sexually reproduce, and 0:16:20.560 --> 0:16:24.240 then it produces those oocytes that the cat poops out, 0:16:24.560 --> 0:16:26.560 and then the cycle can start all over again. 0:16:27.040 --> 0:16:29.520 Right, the parasite has to find its way back to 0:16:29.560 --> 0:16:30.120 the cat. 0:16:30.280 --> 0:16:34.360 Yes, Yeah, so there's a huge amount of incentive on 0:16:34.440 --> 0:16:37.200 the part of the parasite to make sure that they 0:16:37.240 --> 0:16:39.120 make it into the cat. 0:16:41.040 --> 0:16:43.240 Yeah, it's a. It's gorgeous, it's beautiful. 0:16:43.440 --> 0:16:48.560 It is that being said, what about humans? Yeah, so 0:16:48.680 --> 0:16:52.600 that's the life cycle like in the wild or in whatever. 0:16:52.720 --> 0:16:58.680 That's how Toxoplasma gandhi evolved to exist. So what are humans? 0:16:58.720 --> 0:17:01.400 Are we the cat or are we the mouse? The 0:17:01.440 --> 0:17:05.199 mouse or the mouse. So it turns out that we 0:17:05.320 --> 0:17:10.000 can get infected with almost any life stage of the parasite. 0:17:10.200 --> 0:17:13.840 So we can get infected directly from those spoulated oociss 0:17:13.880 --> 0:17:17.080 that cats poop out. So that means if we get 0:17:17.119 --> 0:17:21.200 in contact with cat poop directly, or with contaminated soil 0:17:21.720 --> 0:17:25.760 or contaminated water, or maybe contaminated vegetables that haven't been 0:17:25.880 --> 0:17:29.239 washed or cooked, then we can get infected with that 0:17:29.400 --> 0:17:34.720 first stage, those tachizoites. Okay, those are the stage that's 0:17:34.760 --> 0:17:41.679 gonna invade tissues locally, that's gonna replicate really rapidly. But 0:17:42.040 --> 0:17:46.359 we can also get infected with those tissue cyst stages 0:17:46.880 --> 0:17:50.520 that would normally want to be eaten by a cat, 0:17:50.800 --> 0:17:54.919 the brady zoites inside tissue cysts, gotcha, So if you 0:17:55.160 --> 0:17:59.800 eat contaminated meat, for example, then you can get infected 0:17:59.840 --> 0:18:03.960 with that life stage. However, since we're not cats, the 0:18:04.000 --> 0:18:06.679 parasite can't complete its life cycle inside of humans. 0:18:07.119 --> 0:18:09.199 We're a dead end host, just like in lime disease. 0:18:09.440 --> 0:18:10.800 Just like in lime disease. 0:18:10.600 --> 0:18:14.760 We're not contributing to the parasite life cycle. And like 0:18:14.840 --> 0:18:16.639 the prevalence. 0:18:16.400 --> 0:18:21.480 Unless a cat ad us which does happen, could happen, Yeah, could. 0:18:21.280 --> 0:18:26.120 Happen, and it definitely happened prehistorically for sure. Apparently cats 0:18:26.119 --> 0:18:28.800 are like a major, major predator of humans, which may 0:18:28.840 --> 0:18:31.560 are like of the ancestors of humans, which makes total senating. 0:18:31.800 --> 0:18:36.640 Yeah yeah, okay, So in humans, then the main way 0:18:36.640 --> 0:18:41.200 that this parasite causes disease is in two main ways. 0:18:41.480 --> 0:18:45.399 First by invading cells and tissues, so it can cause 0:18:45.480 --> 0:18:49.600 direct damage in those tissues that it invades, and by 0:18:49.640 --> 0:18:54.120 forming tissue cysts in really important places in our body 0:18:54.359 --> 0:19:00.440 where you shouldn't have cysts full of parasites. Cool cool, cool, 0:19:00.560 --> 0:19:04.120 but yeah, okay, got it all right, So let's talk 0:19:04.160 --> 0:19:08.800 about the symptoms that we see in toxicplasma infection. The 0:19:08.960 --> 0:19:12.560 good news is that the vast majority of people who 0:19:12.600 --> 0:19:15.879 get infected, something like eighty to ninety percent of people 0:19:16.119 --> 0:19:18.040 will be entirely asymptomatic. 0:19:18.359 --> 0:19:18.719 That's it. 0:19:18.800 --> 0:19:22.520 I for some reason, I expected it to be higher asymptomatic. 0:19:22.680 --> 0:19:24.640 You said eighty to ninety are asymptomatic. 0:19:24.720 --> 0:19:27.400 Yeah, yeah, okay, yeah. 0:19:27.000 --> 0:19:30.159 But okay, So even of those ten percent of people 0:19:30.200 --> 0:19:34.080 who maybe do show symptoms, the vast majority of those 0:19:34.160 --> 0:19:38.760 people will have a very non specific, self limited illness, 0:19:39.200 --> 0:19:43.160 so they'll feel a little sick, kind of cruddy. And 0:19:43.400 --> 0:19:50.080 the most classic sign of an initial toxoplasmosis infection is lymphatinopathy. 0:19:50.160 --> 0:19:54.800 So your lymph nodes get swollen, Okay, and that's pretty 0:19:54.880 --> 0:19:58.679 much it. Those lymph nodes usually aren't very tender, and 0:19:58.720 --> 0:20:00.679 they can stay enlarged for like a month or so 0:20:01.440 --> 0:20:04.320 the vast majority of the time, So that's even if 0:20:04.320 --> 0:20:07.080 you have symptoms, the vast majority of time, that'll be 0:20:07.320 --> 0:20:12.520 kind of your only symptoms, So not that big of 0:20:12.560 --> 0:20:16.240 a deal in that case. However, in some cases, a 0:20:16.320 --> 0:20:23.080 primary infection can invade specific organs and then cause illness 0:20:23.200 --> 0:20:29.160 in those organs. So if those tachisoites swim through and find, 0:20:29.560 --> 0:20:33.000 say your heart tissue, your heart is a giant muscle, 0:20:34.080 --> 0:20:36.399 so it wouldn't be surprising for them to try and 0:20:36.480 --> 0:20:39.679 find and insist in your heart muscle, then then you 0:20:39.720 --> 0:20:43.199 could get something called myocarditis, which just means inflammation of 0:20:43.200 --> 0:20:48.280 your heart muscle. If those tachisoites invade your lungs, you 0:20:48.400 --> 0:20:53.639 might get anumanitis. If they invade your liver, a hepatitis. Okay, 0:20:54.000 --> 0:20:58.399 all of these are theoretically possible, they have happened, but 0:20:58.480 --> 0:21:00.000 they don't happen very commonly. 0:21:01.359 --> 0:21:05.080 Is there anything so, I know, like immunocompromise is one 0:21:05.160 --> 0:21:08.520 big aspect of where this might happen more than others. 0:21:08.520 --> 0:21:11.439 But is there anything else that is like makes you 0:21:11.480 --> 0:21:14.240 more susceptible to organ invasion? 0:21:14.400 --> 0:21:16.880 That's a really good question. So the only other thing 0:21:16.960 --> 0:21:19.800 besides immunal compromise, which I'll talk in more detail about 0:21:19.800 --> 0:21:23.480 in just a second, is potentially strain differences. 0:21:23.920 --> 0:21:25.280 So there are a number of. 0:21:25.160 --> 0:21:29.520 Different genotypes and strains of Toxopasma GANDHII, and there is 0:21:29.560 --> 0:21:34.040 some difference in virulence between those strains. How big of 0:21:34.080 --> 0:21:37.919 a role that plays is not entirely clear. Okay, but 0:21:38.240 --> 0:21:42.200 so yeah, for most people who are healthy, they will 0:21:42.200 --> 0:21:47.440 never have any signs of infection. But in people who 0:21:47.480 --> 0:21:54.280 are immuno compromised, especially in people living with HIV, toxopasma 0:21:54.320 --> 0:21:59.680 can be an extremely serious infection. The most common form 0:22:00.680 --> 0:22:05.119 of toxoplasma infection of toxoplasmosis in people living with HIV 0:22:05.359 --> 0:22:09.760 or people who are otherwise immunocompromised is encephalitis. So that's 0:22:10.000 --> 0:22:13.919 inflammation of the brain. So here's the thing about toxoplasma. 0:22:14.680 --> 0:22:18.919 If you get infected, even if you're asymptomatic, it doesn't 0:22:18.960 --> 0:22:22.399 necessarily mean that you don't have cysts inside of you 0:22:22.800 --> 0:22:27.159 right now. But most of the time, your immune system 0:22:27.280 --> 0:22:29.160 is going to be able to keep those cysts kind 0:22:29.200 --> 0:22:31.560 of in check. They're never going to do anything, they're 0:22:31.600 --> 0:22:35.920 never going to cause harm. But if you become immunocompromised, 0:22:36.600 --> 0:22:41.359 those cysts can reactivate essentially, and then you can get 0:22:41.640 --> 0:22:43.760 the encephalitis later on. 0:22:44.440 --> 0:22:46.000 Okay, yeah, that's bad. 0:22:46.160 --> 0:22:49.520 So you can, like if you have an immuno compromise, 0:22:49.640 --> 0:22:53.120 you could get sick with toxoposmosis from a primary infection 0:22:53.359 --> 0:22:55.800 like this is the first time you got infected, or 0:22:55.880 --> 0:22:58.840 it could be that you've had cysts in your tissues 0:22:59.200 --> 0:23:03.560 and now they're re activating because your immune system is low. 0:23:05.080 --> 0:23:09.200 It's really really serious. It's considered an AIDS defining illness. 0:23:09.720 --> 0:23:14.080 Toxoplasma encephalitis got it in a person living with HIV. 0:23:14.960 --> 0:23:17.119 And then, of course, the other way that you can 0:23:17.119 --> 0:23:22.080 get infected besides eating contaminated meat, which by the way, 0:23:22.600 --> 0:23:25.280 is the most common way that people get infected. 0:23:26.160 --> 0:23:28.359 But I do have to point out there was a 0:23:28.400 --> 0:23:31.280 study that looked at the rate or the prevalence of 0:23:31.320 --> 0:23:35.760 toxoplasmosis in people who were vegetarians and people who were 0:23:35.760 --> 0:23:38.159 not vegetarians and found equal rates. 0:23:38.440 --> 0:23:38.960 Fascinating. 0:23:39.000 --> 0:23:42.479 So, yeah, so it's very very clear that there are 0:23:42.520 --> 0:23:46.879 many different roots for exposure. Absolutely much much beyond cats 0:23:46.960 --> 0:23:49.120 is what much beyond owning a cat I should say is. 0:23:49.160 --> 0:23:53.280 Yeah, owning a cat is generally not even alone, owning 0:23:53.320 --> 0:23:55.639 a single cat is not even considered a risk factor. 0:23:56.359 --> 0:23:58.639 Then we'll talk more about the ecology of that and 0:23:58.680 --> 0:23:59.399 why that is. 0:23:59.640 --> 0:24:04.680 Yeah, But the other way that you can become infected 0:24:04.880 --> 0:24:08.439 is congenital toxoplasmosis, which is what we heard about in 0:24:08.480 --> 0:24:09.480 the first hand account. 0:24:10.040 --> 0:24:10.840 It is horrible. 0:24:11.359 --> 0:24:15.560 So toxoplasma can cross the placenta and then infect the fetus. 0:24:16.119 --> 0:24:19.199 It turns out that this is most common if a 0:24:19.240 --> 0:24:22.800 pregnant person gets infected for the first time while they're pregnant. 0:24:23.800 --> 0:24:27.639 And what's interesting is that the risk of infection of 0:24:27.680 --> 0:24:32.960 the fetus actually increases with gestational age, So the later 0:24:33.080 --> 0:24:36.600 in a pregnancy that a person gets infected, the more 0:24:36.760 --> 0:24:39.840 likely it is that the fetus will be infected, but 0:24:40.520 --> 0:24:45.280 the severity of that infection is opposite, so it decreases. 0:24:45.800 --> 0:24:49.320 So the earlier a fetus gets infected, the more severe 0:24:49.359 --> 0:24:52.640 the outcomes. 0:24:51.040 --> 0:24:54.040 But the less likely they are to become infected. 0:24:53.760 --> 0:25:00.440 Exactly right, so overall, without any treatment for a primary infection, 0:25:00.520 --> 0:25:03.160 So a pregnant person who gets infected while they're pregnant, 0:25:03.200 --> 0:25:06.760 the risk of congenital syphalis is between twenty to fifty percent, 0:25:07.200 --> 0:25:11.280 depending on when during their pregnancy they get infected, what 0:25:11.480 --> 0:25:15.240 strain they're infected with, likely, and how much they're exposed 0:25:15.240 --> 0:25:20.840 to probably as well. Severe infections can result in fetal loss, 0:25:20.840 --> 0:25:25.200