# The Mind-Controlling Parasite That's Already in Your Brain

https://www.youtube.com/watch?v=cp3RKVv6kxI

[00:00] one in three of you watching this video right now has a parasite in your brain that is altering your preferences behavior and personality seriously.
[00:10] when infected individuals are compared with non-infected individuals the infected are found to be more aggressive impulsive and neurotic.
[00:19] additionally infected men are found to be more cold and suspicious of others while infected women are the opposite tending to be more warm trusting and outgoing.
[00:29] today we're we're going to dive deep into all aspects of this mind controlling parasite how it functions how terrified we need to be and how it may have played a role in shaping human culture.
[00:40] but first we have to say its name Toxoplasma gandi is a microparasitic protoo meaning it's a small harmful single cell eukarion.
[00:49] just as a reminder we and every other animal are ukar meaning tandi is more closely related to us than any bacteria despite looking the the way it.
[01:00] does if you take any human population
[01:02] around the world you'll find Toxoplasma
[01:05] infecting 10% all the way to 95% of the
[01:09] population it was even found preserved
[01:11] on an ancient Egyptian mummy so it's
[01:13] likely been evolving alongside us for
[01:16] thousands perhaps millions of years and
[01:18] it doesn't stop there toxo infects
[01:20] nearly every warm-blooded mammal and
[01:23] most birds to similar percentages making
[01:26] it arguably the most serop prevalent
[01:28] pathogen of all all time now Toxoplasma
[01:32] infections can lead to a disease called
[01:34] toxoplasmosis but in most cases it's
[01:36] just a latent infection causing no
[01:39] symptoms that harm the host at least
[01:41] that's what it wants us to think like
[01:43] most life te gandi really has one goal
[01:46] to get laid and it's evolved to do that
[01:49] in One Singular environment the
[01:51] intestines of cats any feel line from
[01:54] Tabby to Tiger is a worthy host because
[01:57] they're the only mammals that have the
[01:59] right around housing acid in their
[02:01] intestines which the Toxoplasma need to sexually reproduce when they mate they produce thousands of uh I never know how to say this oo cysts or oos cysts really
[02:12] I think we need an exorcist because thousands of these little demons are shed into the cat's poop and guess what poop goes everywhere animals eat it they track it around it seeps into the soil it watches over you while you sleep at night you can't escape poop and since these cysts last for years on surfaces without dying this is how Toxoplasma becomes so widespread
[02:34] also this is why you shouldn't clean cat litter while you're pregnant
[02:36] while toxo doesn't really harm us it can harm reproductive function so handling cat poop is a really easy way to contract congenital toxoplasmosis
[02:46] but if cats are the main host for Toxoplasma why does it infect other animals at all
[02:48] rodents with toxoplasmosis behave incredibly strangely
[02:53] they will hiss and pounce at cats often to their own demise normally when you're a mouse and you're mousing
[03:03] about you rely on your sense of smell a lot and certain smells say stinky cat piss for example are recognized as dangerous.
[03:11] so when you smell it you think ah Predator nearby got to run got to hide.
[03:15] but when you're a mouse with toxoplasmosis you'll instead find yourself incredibly attracted to the smell of that piss.
[03:22] the odor is just magnificent so Splendid and divine you can't help but follow its deliciousness and then you die because a cat just found you hanging around its urinal.
[03:34] this is called the Fatal Attraction phenomenon because Toxoplasma is literally inverting an evolved fear response into one of Attraction ultimately leading to the mouse's death.
[03:46] it's turning a healthy piss phobia into a deadly piss Kink I'm sorry I I shouldn't have said that.
[03:54] naturally once this was discovered someone wanted to see if the same thing happens in humans.
[03:58] so a study took urine samples from cats horses dogs tigers and hyenas then had
[04:04] humans rate the pleasantness of the various scents.
[04:06] they found that men with Toxoplasma infections found the smell of cat urine significantly more pleasant than non-infected men.
[04:13] while infected women found it less Pleasant than non-infected women.
[04:16] again we see these opposite effects from Toxoplasma in men and women.
[04:20] like how men's personalities become more cold when infected while women's become more warm.
[04:27] all of the other urine samples in this experiment were rated the exact same level of pleasantness between infected and non-infected groups except for hyenas.
[04:35] which actually had the same results as cats but with a much weaker Trend.
[04:39] scientists have observed that mice with toxoplasmosis show no fear of cats even after their infection clears.
[04:47] meaning it's causing a permanent change in their brain as if flipping a switch that completely overrides a rodent's natural instinct.
[04:57] turning it functionally suicidal.
[04:58] nobody understands the exact mechanisms in how Toxoplasma does this.
[05:04] but one study compared the brains of infected and non-infected mice and found differences in dopamine expression.
[05:11] of course it'd be dopamine it always ends up being dopamine but yeah Toxoplasma may be using host neurotransmitters to essentially rewire pathways in the brain.
[05:20] alongside this toxo also increases aggression so you end up with mice that are running up and attacking their natural predators.
[05:26] clearly this is no coincidence because after the mouse gets itself eaten the toxo very conveniently ends up in the place it wants to be.
[05:35] so it seems that t gandi has adapted to mind control rodents in order to increase its likelihood of reproduction.
[05:42] rodents here are an intermediate host for Toxoplasma while cats are the definitive host.
[05:48] previously on this channel I used the example of the green banded brood a flatworm that infects snails by pulsing up and down their eye stalks.
[05:57] this mimics cat caterpillars so that birds will be enticed to find and eat the snail and the Brut saach is then able to reproduce.
[06:05] inside the bird it seems there's a trend among parasites to manipulate their intermediate hosts in an incredibly invasive way just to get them eaten by a definitive host that they really don't harm in a similar capacity and this is probably why we aren't nearly as affected by Toxoplasma as myar we aren't as good of an intermediate host because we're a lot less likely to get eaten by a cat and yet Toxoplasma continues to infect us and a bunch of animals that never interact with cats at all is it waiting for the perfect opportunity to mutate and control us then take over the world that would be scary and I won't say impossible but it's highly unlikely considering there wouldn't really be any evolutionary pressure for that to happen so you probably don't have to worry about this becoming the zombie virus probably a better explanation is that there is no good explanation mammals are all kind of the same we have the same internal organs the bones in our fingers are the same bones that stretch out into
[07:06] bat wings or close down into whale fins
[07:08] and if you go down into the level of neurons in the brain you literally can't tell the difference between a mouse's brain and a human one
[07:14] so it's possible that Toxoplasma adapted solely for rodents and cats but because we're just so similar to them it happens to be able to infect us too
[07:24] on the other hand Toxoplasma might infect us as a roundabout way to get to a cat
[07:31] like sure a moose will probably never get eaten by a cat but if Toxoplasma can infect the Moose it can be released in its poop then get eaten by a mouse which is then killed by a bird which then flies across the world and is hunted by a lion
[07:43] it isn't as if Toxoplasma is in much of a hurry to get to a cat
[07:46] as I said it can survive for a really long time outside on surfaces and even in hosts that it can't sexually reproduce within
[07:55] it can still asexually reproduce creating copies of itself to indefinitely
[08:01] either way infecting multiple species is just something that pathogens do
[08:03] some of the worst diseases in history jumped to
[08:08] humans from animals the black plague Ebola covid-19 allegedly did we ever figure that out by the way like was it a bat penglin a lab I don't know but maybe we should consider ourselves lucky that Toxoplasma isn't nearly as dangerous to us as any of these though it's actually because it's not dangerous that it's able to spread as much as it has remember during Co when we figured out that some people were asymptomatic and were spreading Co despite not having any of the symptoms themselves it made the whole thing a lot trickier to contain because it's hard to stop the spread when you don't know who's spreading it since we're asymptomatic to Toxoplasma infections it spreads Among Us without any resistance which is probably why 30% of the world has it and has no idea it even exists as I've been editing this video I kept coming across more crazy things things about Toxoplasma some of which I just had to include first of all it's linked with schizophrenia OCD bipolar disorder and most recently like
[09:08] a month ago as of recording this a paper came out finding a positive relationship between Toxoplasma infections and anxiety disorders.
[09:15] now all of this is correlational data which means it's not confirmed that Toxoplasma leads to mental disorders but looking into this further is definitely necessary so we can see the full scope of what tox is doing to our brain.
[09:29] also since toxo is able to bury itself and stay dormant in your brain some people want to bioengineer it for medical purposes.
[09:39] so literally bringing medicine into your brain via a brain parasite it sounds pretty crazy but this is a potentially very promising technique and it could totally change how we treat brain injuries and mental disorders in the future.
[09:51] but of course it's very early in development we likely won't see it implemented for quite some time if it even works at all.
[09:58] talko plasma has infected us for a long long time so just how much has it impacted us as a species over the years would an early group that was infected with Toxoplasma develop
[10:11] more aggressive traditions and lifestyles compared to a non-infected one.
[10:15] would the seemingly gender dependent effects create exaggerated gender roles in an infected society?
[10:20] let me know what you think in the comments below because your guess is as good as mine.
[10:26] some people suggest that since we've confirmed Toxoplasma was in ancient Egypt and that Toxoplasma makes you like cats that Toxoplasma was the reason that ancient Egyptians woried cats.
[10:35] it's a fun thought but I don't really buy it.
[10:40] for one people finding cat urine less bad than usual is not the same as liking cats more than usual.
[10:45] but also the Egyptians worshiped a lot of animals besides cats and not all of them have a corresponding parasite to explain their divinity.
[10:54] I mean unless we just don't know about that yet.
[10:56] my last video about parasite ended up getting demonetized.
[10:58] hopefully the same won't happen with this one.
[11:02] but YouTube's Advertiser safe guidelines can be really vague.
[11:05] I like talking about these disturbing yet important topics that I feel no one else
[11:11] is really talking about so it's a real bummer to have the income on these videos slashed especially because uh I'm a recent graduate and I don't make that much income so I'm launching YouTube memberships to see if that might help.
[11:23] if you want to learn about what you get if you're a member you can click the join button below to see what I'm offering.
[11:28] otherwise just watching another video of mine helps me tremendously so consider checking out this one up here and uh thanks for watching.