July 14, 2009 • 20 mins
Toxoplasmosis is a parasitic infection that favors cats, but it can also be found in humans. Discover the disturbing details of how toxoplasma gondii finds a host -- and how it affects human beings -- in this podcast from HowStuffWorks.com.
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Speaker 1 (00:00):
Brought to you by the reinvented two thousand twelve camera.
It's ready. Are you welcome to stuff you should know
from house Stuff Works dot Com. Hey, and welcome to
the podcast. I'm Josh Clark. With me is the always
lovely and effervescent Charles W. Bryant. I have on shorts today.
Do you do you look like you're ready to go
(00:21):
to the beach or play basketball or play beach at
the basketball and I'm at the opposite of that. Play
basketball the beach. Yeah, you can do that in southern California, buddy,
You can do anything in southern California. Show us what
I hear? Yeah, I can do anything because my wife's
side of town. I know. Chuck's a bachelor today, batching
it as we say. He looks terrible. He's dressed shabbily,
(00:44):
clearly hasn't showered, food stuff staying down in the front
of his shirts. Steak in his beard. That's a big
hunk of steak on your beard? Is so? Chuck? How
you feeling? I feel a little tired and under the
weather because of my bachelor experiences, but I am ready
to go. Are you you're bringing it? Yes? So Chuck
(01:08):
Um you know how neurotic I am right like, right now,
I'm thinking about what you're really thinking about me. Yeah,
you're a little neurotic. I wouldn't say hugely neurotic. I'm
definitely not Woody Allen neurotic. No, no, no, But things
like gil self doubt. Um uh what was the third one?
Self doubt? You always think you stink on the show,
which is just ridiculous. Oh I do, because you're good regardless.
(01:31):
These things drive me right. Um so yeah, I would
consider myself fairly neurotic. And I recently found out Chuck
um actually thanks to a new show that has inspired
this podcast and the next one. We're doing a pair
of them on parasites. It's an Animal Planet show actually
called Monsters Inside of Me. Yes, and the staff is
(01:52):
parasite crazy right now. It's all over the blogs that
blogs are lousy with parasites, lousy with parasites because it's
a really cool show. Have you seen aunt, I've seen
parts of it. Yeah, it is wicked. Yeah, I like it.
I think it's cool, mainly though, because it relieves me
from any responsibility from my own personality and own horrible, disappointing, obnoxious,
(02:16):
personality actually probably is the result of a latent infection
by a little thing called toxoplasma Gandhi T, gandhi gandhi.
I'm gonna I'm gonna call it taxo. You can call
it T, you can call it T. I'll call it taxo, Yeah,
just just for ease of pronunciation. But yeah, this is
a parasite. It's a zootic disease, which means we catch
(02:39):
it from animals. Right, It's a relative of malaria, it is.
But this thing is possibly running the world. Yeah, it was.
This is a little disturbing. I gotta tell you a
ted bit. So so let's talk about T. Let's talk
about taxo. Yeah. Uh it is a parasite, as we said,
as a complex life cycle. Like most parasites, uh, and
(03:03):
the life cycle is has a purpose to get into
its final host. And that word just creeps me out,
the host or definitive host. Yeah, yeah, and um, this
one is unusual because it it completes this life cycle
in one place, in one place only, and that is
inside of a cat. A cat's and a guts that
cats gut. Yeah, this is where uh T wants to
(03:26):
be because this is where it gets it on and
reproduces everywhere else it does. It goes to incredible lengths
to get back into the cat gut. Yeah, it's crazy,
like like really honestly, we haven't we haven't gotten into
this yet, but this is this is like master Blaster
from from Thunderdome. It's like the little guy like just
(03:49):
running things in and making whatever it needs to carry
it to the cat gut, do whatever it wants to
get it into the cat gut. Right and uh, toxoplasma
is actually um really common. Estimates run into as much
as eight percent of the world population is infected has
(04:10):
latent infection with toxoplasma, right, um, sixty seven percent of
Brazilians alone. Yeah, but then on the other side, seven
percent of the UK is infected. So yeah, it's lopsided. Um.
And this may sound familiar already because for many, many
years we've known that pregnant women should stay away from
cat feces to pick up the infection. Go ahead and
(04:34):
say that our guest producer. We have a guest producer
this week. Oh yeah, hey, Lizzie Lovely in Fetching Lizzie.
She thought I was kidding with her when I told
her that, Oh, really, I think pregnant women can't clean
out the cat box. She thought I was pulling her
leg and I was gonna like pull one on her.
That was actually like the first public health warning I
have I ever came across. I've known that since I
was you know, kneehi to a grasshopper. Yeah, I love
(04:56):
that phrase. Yeah. So yeah, you you're not allowed. You're
not allowed. You're not so post to um the police
cat box, police wire can be you're not supposed to
clean out the cat box if you're with child, because, uh,
fetus is one of the ways one of the things
that can be harmed. Yeah, effects like serious birth defects. Um. So, yeah,
(05:17):
if you are, if your lady is pregnant, you want
to go ahead and take care of cleaning out the
cat box during that nine months, because that's how toxoplasma
infections result from handling cat feces or more specifically, and
I got the impression that it's much more virulent when
cat feces mixes with soil, right, it has much more
(05:39):
staying power, that kind of thing. So, if you have
a cat that likes to poop in your garden and
you're a big gardener, you're gonna want to murder your
cat and uh get rid of all of your top
soil and start over again, right. Uh. I imagine you
could also get it from eating a rat, because rats
and mice tend to get it as well. But you
can also very easily get it from eating undercooked livestock,
(06:04):
especially that has been around cat feces. I mean, how
many farms have cats on them? Quite a few outs.
So let's talk about the life cycle of this because
it's it's interesting that you mentioned rats or mice, because
these things are under arguably the most control of tea.
You know that confuses me because I had a car
named T so all right, i'll call it Taxo. Alright,
(06:26):
a car named Taxo as well? Man, did you have
one named T Gandhi? Okay, well I'll go with that one, thanks, Chuck.
You know I have a speech impediment. We'll go with Taxo. Okay,
So Taxo gets into the soil. Let's say your little kid,
he goes and poops outside, and mouse passes by the soil,
passes over, it eats, it, rolls around in, it plays
(06:46):
with it, makes a little clay sculpture out of it.
And that's his friend um, and the rats infected. So
this parasite actually goes through the bloodstream and travels to
the brain where all sorts of freaky freaky off start
happening to the rats behavior rat or mouse. And that's
slightly alarming to us because, as everyone knows, which is
(07:07):
why we use lab rats, we have very similar brains
to rats. Yeah, chemically the way it's put together the
whole deal, which I've always thought was interesting. Well, let's
talk about rats as the intermediate host. So now a
rat is infected with toxoplasmosis. Gross. Uh, it's brain is
being taken over. What are some of the weird things
that begin happening. Well, one thing that I thought was
(07:29):
most disturbing was they actually become fond of cat urine.
They do, they're attracted to the scent. And they did
a test opposite of what's supposed to happen. Yeah, they
did a test where they did you see the one
with a little sleeping they made the little beds for
the rats, and that one of them was soaked in
cat urine, and they would actually go for that bed.
They prefer that bedding over their normal bedding. Yeah. Um,
(07:52):
which is really weird, really weird. I wrote of another
study that found that these these rats were actually attracted
to cat your not just cent of it. They would
go and investigate cat urine and they they investigated the
brains of these rats, meaning they chopped their heads off
and cut their from them open and um. They didn't
just ask some questions. Although they did do studies, um like,
(08:15):
they did different trials, and what they found essentially was
that the rats are rodents lose specifically their fear of
cat urine. Okay, that's it. Everything else remains intact. All
other innate fears that they have, that that all rats
and mice display remain intact. It's just their fear of
(08:35):
cat urine. So they're attracted to cat urine. Plus also, uh,
toxo has an effect on your motor reflexes, so you're
not quite as fast as you used to be. Right.
So these two things together in attraction to cat urine,
the scent of cat urine and slow reflex time. That
means that you can get eaten by a cat, and
that means you get into your final host. Right. That
(08:57):
means the toxoplasmas, the toxoplasma has made its way back
into its definitive host, the guts of the cat, the
brain of the rodent. It is the coolest, most frightening
thing I've ever heard of in my entire life. It
really is, because, like you said, Chuck, like, rodent brains
are very similar to humans in composition, at least chemically, right.
(09:19):
That's why we're always experimenting on rodents um to find out,
you know, how we can treat schizophrenia, that kind of thing. So,
which leads us to since of the human population is
infected with a latent toxoplasma infection, is it having an
effect on us? It looks like yes, well yeah, For
(09:40):
many many years they always said, oh, so many people
have it, but it's really not the big of a
deal because once it enters the human body, it's kind
of uh, we're not gonna get eaten by a cat
anymore like a lion or a tiger. So not only
it doesn't matter once we're infected, they go and inform
resistant cysts. Basically just hide and then say it. They
(10:00):
don't do anything. They set up camping your body, right,
but that's that. That generally, that's it, unless you have
AIDS or another repressed immune system disease or that's when
it can, right, but it's gonna just sit there because
we have anybodies that can you know, keep them in check.
But that's what we thought exactly. But around I think
is when they really started to begin to look to
(10:22):
see what kind of behavioral changes toxoplasmosis might cause in humans.
And we started to find some startling results like that
lowered um motor reflex time. Right. They did some tests that,
uh that I know that. They did a couple one
where they were supposed to stroke a specific keystroke on
the keyboard in a certain amount of time. In another way,
(10:43):
they showed a white recognition test where they showed like
a white square on the screen and you were supposed
to react when you saw the white square. And they
found that people that had the latent toxoplasmosis would, uh
there was a lag that were definitely behind the rest
of the crowd and recognizing these things. Right, you know
to that study, your buddy, a guy named Dr Yaroslav Flag.
(11:04):
You just talked to him. I just talked to the
guy on the phone. This guy is arguably the pre
eminent expert. He's a parasitologist out of Charles university in Prague.
Did you call Prague? Just now? No way, And I
need to expense that because I did it on my
cell phone because you know, I'm not comfortable talking about
my desk because I'm neurotic because I have tlaxo plasmosis.
(11:24):
Paying right, So this uh Dr flager Um, who is arguably, uh,
the the foremost authority toxoplasmosis um. He conducted that study
Uh anymore? Right? He? I think he conducted eleven and
in nine of the eleven studies, Uh, there was a
significant difference between people who are infected with taxoplasmosis and
(11:46):
people who weren't. In humans, there's actually an equal and
opposite effect defined by gender. This is what I thought
was really interesting. It's odd, it was almost dead opposite
the way men and women were affected by this thing. Yeah. So,
and women just kind of got kind of got out
of head in this deal. Yeah when you say so,
(12:06):
these are the women we love that toxoplasmos has infected women.
That's my favorite women who have who have are t
infected and not Chuck's car, but the other kind. Uh.
They tend to be a warmhearted, outgoing, conscientious, moralistic. These
are wonderful women, the salt of the earth. Yeah, but
(12:27):
also outgoing, you know, I mean like everybody loves a
gal who's willing to just try anything. And um, you
know is is but it also has a line which
is moralistic. So yeah, men, though men got the bat
into the stick, we did. We tended to be uh,
stupid er but more loyal? Is stupid or a word?
(12:48):
Are you toxoplasmatic? I am less intelligent, more loyal, frugal,
which was interesting, and mild tempered and dogmatic. Did you
say dogmatic? I did not, so dogmatic meaning inflexible basically,
but they're both basically Guys who are infected with toxo
plasmosis are jerks and women who are infected are cool. Yeah,
(13:08):
but they're both neurotic. That was the one shared trait, right,
And so I talked to Dr Flagger and I was asking,
you know, where are we as far as understanding how
toxo plasmois could affect us physiologically our brain? And um,
one thing I saw that kept coming up as neurotransmitters.
He said. The likeliest candidate is dopamine, or dopamine as
(13:28):
he put it. He said, it increases levels UM. And
he also has found that there are increased levels of
UM testosterone and men lowered levels of testosterone and women
who are infected with toxoplasmosis. So he he said in
his opinion, that would account for it. Again, he's he's
a stickler and pointing out um correlation not causation. We
(13:52):
are definitely at the correlation stage and understand absolutely plasmosis
can affect human behavior. But he's finding some really cool stuff. Yeah,
that's interesting about the It kind of makes sense with
the testosterone levels because they found that, like we said earlier,
sixty seven percent of Brazilians are infected with this stuff. Uh,
and countries they found where uh, there were a lot
(14:15):
of people infected with this or more likely to have
masculine sex roles or more divergent gender roles are more
pronounced distinction among exactly, Like the men go out and
their masculine they do the hard work, and the women
they work inflexibly exactly. Yeah, and the women are just
like that's my man. Yeah, I felt very interesting. Yeah,
(14:35):
I mean think about it. If the population is infected
with a latent toxic with latent toxoplasmosis, then yeah, this
would conceivably alter cultures. Still a little hinky if you
ask me, I don't know, man, it's still it's still
new research. But I'm thinking it's to look like this
parasite rules the world. Well it could because we rule
(14:56):
the world, were ruled by toxoplasma. Ergo oxo plasma rules
the world. I think it's a bunch of factors. That's me,
that's my camp, so you know. UM Flagger also conducted
us study back in two thousand two, UM in Prague
where he is, the driving test he I think it
(15:16):
was a hundred and sixties seven people who were identified
as the causes of car accidents, either as pedestrians or drivers,
which I thought was also interesting. And um he found
that people with toxo plasmosis are two point six five
times more likely it's almost three times it's likely to
be involved in a car accident. Is someone who's not infected.
(15:38):
I think that goes back to the latent reaction time.
Wouldn't you think it could be the delayed reaction Again
though there's there's well yeah, yeah, the are motor skillsops right,
crash sure, um, or if it makes us more reckless,
like if you're a man, right, because we said that
that you're more willing to break rules if if you're
(15:59):
a man infective with taxola lights screw it exactly. Or
this Carl stopped for me if I went in front
of it, that kind of thing. But again we're we're
at the cause where the correlation not causation stage, so
everyone points that out. It's entirely possible that people in
Prague who have cats and would be more likely to
be infected with taxoplasmosis are also more likely to um
(16:23):
zone out while driving thinking about how Princess Lady would
look really good in a little cattre that you saw
inline that morning, And they said it could be a
personality thing, which I thought that was a little hanky too.
But there's also a correlation between schizophrenia and toxoplasmosis. Not hanky, No,
this is a there's a there's a definite link. Uh.
(16:43):
And there's also a neurotransmitter called nitric oxide. This is
not flagger. Flager actually said that he had not done
much research on nitric oxide or nitric oxide as he
called it. But actually, some guys from Toledo, my hometown,
some psychiatrists have been researching into it and there are
increased levels of nitric oxide in schizophrenics and uh toxoplasmatics
(17:06):
and schizophrenics or or more likely to own cats, which
I thought was odd. So says the University of Maryland, right,
they own cats because the taxoplasmosis and the neighbor's dog
tell them to write. Actually, not University of Maryland, sorry,
Stanley Medical Research Center in Maryland. I just want to
clear that up. So, Chuck, what do you think? You
think it's still hinky? I think it's slightly hinky. I
(17:28):
think there's something to it, but I think it's um.
Like I said, I think it's one of many factors. Probably.
I don't think you can chock up the machismo of
the Brazilian man to cat boo just yet. So that's taxoplasmosis.
But um, if you are into parasites or this podcast
has piqued your interest, Chuck and I would both strongly
recommend that you watch that new show Monsters Inside of
(17:50):
Me on Animal Planet. What is it Wednesdays at nine?
Wednesdays at nine. It's cool show. Yeah, cool graphics like
CG They get inside your body. Isn't like as if
you were a parasite. It's yeah, our parent company, Discovery
definitely threw some money at this one. It looks very cool, definitely. Yeah,
so check that out. And we also have tons of
cool stuff. You can also check out the Monsters inside
(18:11):
of Me website. Yeah, Robert Lamb, Robert Lamb wrote some
ki cool stuff and actually we have to give him
a big thanks for pointing us, uh the in the
right direction for research on this this particular podcast. He
knows what he's doing. He's parasitastic. And of course, um,
how Stuff Works dot Com has tons of stuff on it,
and if you're interested, you can also read all of
our blog posts on it. There's like five million of
(18:33):
them and each one's better than the last. Yeah. That's
it for plugging, isn't it. So yeah, plug heavy, which
means buddy, it is time for a listener mayo. So, Josh,
I'm just gonna call this, uh, we're awesome because we
saved a woman's life. Yeah, this is crazy. It is
(18:54):
slightly hanky, but I'll take I'll take credit. Uh. Bonnie
from Boulder, Colorado wrote in, and Bonnie says, this, Hi, guys,
stuff you should know just saved my life. The facts
for these. I was driving home and had just finished
listening to your hyper Miling podcast. As a result, I
was only going forty miles per hour on a stretch
of highway where I usually go sixty. All of a sudden,
(19:15):
there was a pair of headlights right in front of me.
Some genius was going the wrong way in the same
lane of the highway as me. Short story even shorter.
I ended up facing the wrong way on the highway
thanks to some recent rain and some awful skidding and sliding,
But due to the late hour, lack of other cars,
and my slow speed, I avoided hitting anything. Who knows
if I would have had a head on collision if
(19:35):
I had been going my normal speed, But I do
know that thanks to YouTube and you're always enlightening podcasts,
I will never have to night. Many thanks. You're immensely
appreciative listener and fan. Bonnie of Boulder, Colorado, Thank you, Bonnie. Awesome. Honestly,
what if she would have been going twenty miles an
hour that could have made all the difference? Oh yeah, definitely,
even if it was just a fluke thing, I'll take credit.
(19:56):
Even if it wasn't fluke, we still picked up an
indentured servant for a lot. Yeah, and I personally I
think we should get a key to the city of
Boulder show. Yeah, I've always I've been England for one
of those for a long time. Key to any city,
No Boulder, Okay, Yeah, I think this is this is
our end for sure. Maybe a T shirt even sure? Yeah,
life and all I got is this lousy T shirt.
(20:19):
That's a good one. If you have any good T
shirt ideas or any instances of how Chuck and I
saved your life, you can send them in an email
to stuff podcast at how stuff works dot com. For
more on this and thousands of other topics. Is it
how stuff works dot com. Want more how stuff works,
(20:42):
check out our blogs on the house. Stuff works dot
com home page. Brought to you by the reinvented two
thousand twelve camera. It's ready, are you
Brought to you by the reinvented two thousand twelve camera.
It's ready. Are you welcome to stuff you should know
from house Stuff Works dot Com. Hey, and welcome to
the podcast. I'm Josh Clark. With me is the always
lovely and effervescent Charles W. Bryant. I have on shorts today.
Do you do you look like you're ready to go
(00:21):
to the beach or play basketball or play beach at
the basketball and I'm at the opposite of that. Play
basketball the beach. Yeah, you can do that in southern California, buddy,
You can do anything in southern California. Show us what
I hear? Yeah, I can do anything because my wife's
side of town. I know. Chuck's a bachelor today, batching
it as we say. He looks terrible. He's dressed shabbily,
(00:44):
clearly hasn't showered, food stuff staying down in the front
of his shirts. Steak in his beard. That's a big
hunk of steak on your beard? Is so? Chuck? How
you feeling? I feel a little tired and under the
weather because of my bachelor experiences, but I am ready
to go. Are you you're bringing it? Yes? So Chuck
(01:08):
Um you know how neurotic I am right like, right now,
I'm thinking about what you're really thinking about me. Yeah,
you're a little neurotic. I wouldn't say hugely neurotic. I'm
definitely not Woody Allen neurotic. No, no, no, But things
like gil self doubt. Um uh what was the third one?
Self doubt? You always think you stink on the show,
which is just ridiculous. Oh I do, because you're good regardless.
(01:31):
These things drive me right. Um so yeah, I would
consider myself fairly neurotic. And I recently found out Chuck
um actually thanks to a new show that has inspired
this podcast and the next one. We're doing a pair
of them on parasites. It's an Animal Planet show actually
called Monsters Inside of Me. Yes, and the staff is
(01:52):
parasite crazy right now. It's all over the blogs that
blogs are lousy with parasites, lousy with parasites because it's
a really cool show. Have you seen aunt, I've seen
parts of it. Yeah, it is wicked. Yeah, I like it.
I think it's cool, mainly though, because it relieves me
from any responsibility from my own personality and own horrible, disappointing, obnoxious,
(02:16):
personality actually probably is the result of a latent infection
by a little thing called toxoplasma Gandhi T, gandhi gandhi.
I'm gonna I'm gonna call it taxo. You can call
it T, you can call it T. I'll call it taxo, Yeah,
just just for ease of pronunciation. But yeah, this is
a parasite. It's a zootic disease, which means we catch
(02:39):
it from animals. Right, It's a relative of malaria, it is.
But this thing is possibly running the world. Yeah, it was.
This is a little disturbing. I gotta tell you a
ted bit. So so let's talk about T. Let's talk
about taxo. Yeah. Uh it is a parasite, as we said,
as a complex life cycle. Like most parasites, uh, and
(03:03):
the life cycle is has a purpose to get into
its final host. And that word just creeps me out,
the host or definitive host. Yeah, yeah, and um, this
one is unusual because it it completes this life cycle
in one place, in one place only, and that is
inside of a cat. A cat's and a guts that
cats gut. Yeah, this is where uh T wants to
(03:26):
be because this is where it gets it on and
reproduces everywhere else it does. It goes to incredible lengths
to get back into the cat gut. Yeah, it's crazy,
like like really honestly, we haven't we haven't gotten into
this yet, but this is this is like master Blaster
from from Thunderdome. It's like the little guy like just
(03:49):
running things in and making whatever it needs to carry
it to the cat gut, do whatever it wants to
get it into the cat gut. Right and uh, toxoplasma
is actually um really common. Estimates run into as much
as eight percent of the world population is infected has
(04:10):
latent infection with toxoplasma, right, um, sixty seven percent of
Brazilians alone. Yeah, but then on the other side, seven
percent of the UK is infected. So yeah, it's lopsided. Um.
And this may sound familiar already because for many, many
years we've known that pregnant women should stay away from
cat feces to pick up the infection. Go ahead and
(04:34):
say that our guest producer. We have a guest producer
this week. Oh yeah, hey, Lizzie Lovely in Fetching Lizzie.
She thought I was kidding with her when I told
her that, Oh, really, I think pregnant women can't clean
out the cat box. She thought I was pulling her
leg and I was gonna like pull one on her.
That was actually like the first public health warning I
have I ever came across. I've known that since I
was you know, kneehi to a grasshopper. Yeah, I love
(04:56):
that phrase. Yeah. So yeah, you you're not allowed. You're
not allowed. You're not so post to um the police
cat box, police wire can be you're not supposed to
clean out the cat box if you're with child, because, uh,
fetus is one of the ways one of the things
that can be harmed. Yeah, effects like serious birth defects. Um. So, yeah,
(05:17):
if you are, if your lady is pregnant, you want
to go ahead and take care of cleaning out the
cat box during that nine months, because that's how toxoplasma
infections result from handling cat feces or more specifically, and
I got the impression that it's much more virulent when
cat feces mixes with soil, right, it has much more
(05:39):
staying power, that kind of thing. So, if you have
a cat that likes to poop in your garden and
you're a big gardener, you're gonna want to murder your
cat and uh get rid of all of your top
soil and start over again, right. Uh. I imagine you
could also get it from eating a rat, because rats
and mice tend to get it as well. But you
can also very easily get it from eating undercooked livestock,
(06:04):
especially that has been around cat feces. I mean, how
many farms have cats on them? Quite a few outs.
So let's talk about the life cycle of this because
it's it's interesting that you mentioned rats or mice, because
these things are under arguably the most control of tea.
You know that confuses me because I had a car
named T so all right, i'll call it Taxo. Alright,
(06:26):
a car named Taxo as well? Man, did you have
one named T Gandhi? Okay, well I'll go with that one, thanks, Chuck.
You know I have a speech impediment. We'll go with Taxo. Okay,
So Taxo gets into the soil. Let's say your little kid,
he goes and poops outside, and mouse passes by the soil,
passes over, it eats, it, rolls around in, it plays
(06:46):
with it, makes a little clay sculpture out of it.
And that's his friend um, and the rats infected. So
this parasite actually goes through the bloodstream and travels to
the brain where all sorts of freaky freaky off start
happening to the rats behavior rat or mouse. And that's
slightly alarming to us because, as everyone knows, which is
(07:07):
why we use lab rats, we have very similar brains
to rats. Yeah, chemically the way it's put together the
whole deal, which I've always thought was interesting. Well, let's
talk about rats as the intermediate host. So now a
rat is infected with toxoplasmosis. Gross. Uh, it's brain is
being taken over. What are some of the weird things
that begin happening. Well, one thing that I thought was
(07:29):
most disturbing was they actually become fond of cat urine.
They do, they're attracted to the scent. And they did
a test opposite of what's supposed to happen. Yeah, they
did a test where they did you see the one
with a little sleeping they made the little beds for
the rats, and that one of them was soaked in
cat urine, and they would actually go for that bed.
They prefer that bedding over their normal bedding. Yeah. Um,
(07:52):
which is really weird, really weird. I wrote of another
study that found that these these rats were actually attracted
to cat your not just cent of it. They would
go and investigate cat urine and they they investigated the
brains of these rats, meaning they chopped their heads off
and cut their from them open and um. They didn't
just ask some questions. Although they did do studies, um like,
(08:15):
they did different trials, and what they found essentially was
that the rats are rodents lose specifically their fear of
cat urine. Okay, that's it. Everything else remains intact. All
other innate fears that they have, that that all rats
and mice display remain intact. It's just their fear of
(08:35):
cat urine. So they're attracted to cat urine. Plus also, uh,
toxo has an effect on your motor reflexes, so you're
not quite as fast as you used to be. Right.
So these two things together in attraction to cat urine,
the scent of cat urine and slow reflex time. That
means that you can get eaten by a cat, and
that means you get into your final host. Right. That
(08:57):
means the toxoplasmas, the toxoplasma has made its way back
into its definitive host, the guts of the cat, the
brain of the rodent. It is the coolest, most frightening
thing I've ever heard of in my entire life. It
really is, because, like you said, Chuck, like, rodent brains
are very similar to humans in composition, at least chemically, right.
(09:19):
That's why we're always experimenting on rodents um to find out,
you know, how we can treat schizophrenia, that kind of thing. So,
which leads us to since of the human population is
infected with a latent toxoplasma infection, is it having an
effect on us? It looks like yes, well yeah, For
(09:40):
many many years they always said, oh, so many people
have it, but it's really not the big of a
deal because once it enters the human body, it's kind
of uh, we're not gonna get eaten by a cat
anymore like a lion or a tiger. So not only
it doesn't matter once we're infected, they go and inform
resistant cysts. Basically just hide and then say it. They
(10:00):
don't do anything. They set up camping your body, right,
but that's that. That generally, that's it, unless you have
AIDS or another repressed immune system disease or that's when
it can, right, but it's gonna just sit there because
we have anybodies that can you know, keep them in check.
But that's what we thought exactly. But around I think
is when they really started to begin to look to
(10:22):
see what kind of behavioral changes toxoplasmosis might cause in humans.
And we started to find some startling results like that
lowered um motor reflex time. Right. They did some tests that,
uh that I know that. They did a couple one
where they were supposed to stroke a specific keystroke on
the keyboard in a certain amount of time. In another way,
(10:43):
they showed a white recognition test where they showed like
a white square on the screen and you were supposed
to react when you saw the white square. And they
found that people that had the latent toxoplasmosis would, uh
there was a lag that were definitely behind the rest
of the crowd and recognizing these things. Right, you know
to that study, your buddy, a guy named Dr Yaroslav Flag.
(11:04):
You just talked to him. I just talked to the
guy on the phone. This guy is arguably the pre
eminent expert. He's a parasitologist out of Charles university in Prague.
Did you call Prague? Just now? No way, And I
need to expense that because I did it on my
cell phone because you know, I'm not comfortable talking about
my desk because I'm neurotic because I have tlaxo plasmosis.
(11:24):
Paying right, So this uh Dr flager Um, who is arguably, uh,
the the foremost authority toxoplasmosis um. He conducted that study
Uh anymore? Right? He? I think he conducted eleven and
in nine of the eleven studies, Uh, there was a
significant difference between people who are infected with taxoplasmosis and
(11:46):
people who weren't. In humans, there's actually an equal and
opposite effect defined by gender. This is what I thought
was really interesting. It's odd, it was almost dead opposite
the way men and women were affected by this thing. Yeah. So,
and women just kind of got kind of got out
of head in this deal. Yeah when you say so,
(12:06):
these are the women we love that toxoplasmos has infected women.
That's my favorite women who have who have are t
infected and not Chuck's car, but the other kind. Uh.
They tend to be a warmhearted, outgoing, conscientious, moralistic. These
are wonderful women, the salt of the earth. Yeah, but
(12:27):
also outgoing, you know, I mean like everybody loves a
gal who's willing to just try anything. And um, you
know is is but it also has a line which
is moralistic. So yeah, men, though men got the bat
into the stick, we did. We tended to be uh,
stupid er but more loyal? Is stupid or a word?
(12:48):
Are you toxoplasmatic? I am less intelligent, more loyal, frugal,
which was interesting, and mild tempered and dogmatic. Did you
say dogmatic? I did not, so dogmatic meaning inflexible basically,
but they're both basically Guys who are infected with toxo
plasmosis are jerks and women who are infected are cool. Yeah,
(13:08):
but they're both neurotic. That was the one shared trait, right,
And so I talked to Dr Flagger and I was asking,
you know, where are we as far as understanding how
toxo plasmois could affect us physiologically our brain? And um,
one thing I saw that kept coming up as neurotransmitters.
He said. The likeliest candidate is dopamine, or dopamine as
(13:28):
he put it. He said, it increases levels UM. And
he also has found that there are increased levels of
UM testosterone and men lowered levels of testosterone and women
who are infected with toxoplasmosis. So he he said in
his opinion, that would account for it. Again, he's he's
a stickler and pointing out um correlation not causation. We
(13:52):
are definitely at the correlation stage and understand absolutely plasmosis
can affect human behavior. But he's finding some really cool stuff. Yeah,
that's interesting about the It kind of makes sense with
the testosterone levels because they found that, like we said earlier,
sixty seven percent of Brazilians are infected with this stuff. Uh,
and countries they found where uh, there were a lot
(14:15):
of people infected with this or more likely to have
masculine sex roles or more divergent gender roles are more
pronounced distinction among exactly, Like the men go out and
their masculine they do the hard work, and the women
they work inflexibly exactly. Yeah, and the women are just
like that's my man. Yeah, I felt very interesting. Yeah,
(14:35):
I mean think about it. If the population is infected
with a latent toxic with latent toxoplasmosis, then yeah, this
would conceivably alter cultures. Still a little hinky if you
ask me, I don't know, man, it's still it's still
new research. But I'm thinking it's to look like this
parasite rules the world. Well it could because we rule
(14:56):
the world, were ruled by toxoplasma. Ergo oxo plasma rules
the world. I think it's a bunch of factors. That's me,
that's my camp, so you know. UM Flagger also conducted
us study back in two thousand two, UM in Prague
where he is, the driving test he I think it
(15:16):
was a hundred and sixties seven people who were identified
as the causes of car accidents, either as pedestrians or drivers,
which I thought was also interesting. And um he found
that people with toxo plasmosis are two point six five
times more likely it's almost three times it's likely to
be involved in a car accident. Is someone who's not infected.
(15:38):
I think that goes back to the latent reaction time.
Wouldn't you think it could be the delayed reaction Again
though there's there's well yeah, yeah, the are motor skillsops right,
crash sure, um, or if it makes us more reckless,
like if you're a man, right, because we said that
that you're more willing to break rules if if you're
(15:59):
a man infective with taxola lights screw it exactly. Or
this Carl stopped for me if I went in front
of it, that kind of thing. But again we're we're
at the cause where the correlation not causation stage, so
everyone points that out. It's entirely possible that people in
Prague who have cats and would be more likely to
be infected with taxoplasmosis are also more likely to um
(16:23):
zone out while driving thinking about how Princess Lady would
look really good in a little cattre that you saw
inline that morning, And they said it could be a
personality thing, which I thought that was a little hanky too.
But there's also a correlation between schizophrenia and toxoplasmosis. Not hanky, No,
this is a there's a there's a definite link. Uh.
(16:43):
And there's also a neurotransmitter called nitric oxide. This is
not flagger. Flager actually said that he had not done
much research on nitric oxide or nitric oxide as he
called it. But actually, some guys from Toledo, my hometown,
some psychiatrists have been researching into it and there are
increased levels of nitric oxide in schizophrenics and uh toxoplasmatics
(17:06):
and schizophrenics or or more likely to own cats, which
I thought was odd. So says the University of Maryland, right,
they own cats because the taxoplasmosis and the neighbor's dog
tell them to write. Actually, not University of Maryland, sorry,
Stanley Medical Research Center in Maryland. I just want to
clear that up. So, Chuck, what do you think? You
think it's still hinky? I think it's slightly hinky. I
(17:28):
think there's something to it, but I think it's um.
Like I said, I think it's one of many factors. Probably.
I don't think you can chock up the machismo of
the Brazilian man to cat boo just yet. So that's taxoplasmosis.
But um, if you are into parasites or this podcast
has piqued your interest, Chuck and I would both strongly
recommend that you watch that new show Monsters Inside of
(17:50):
Me on Animal Planet. What is it Wednesdays at nine?
Wednesdays at nine. It's cool show. Yeah, cool graphics like
CG They get inside your body. Isn't like as if
you were a parasite. It's yeah, our parent company, Discovery
definitely threw some money at this one. It looks very cool, definitely. Yeah,
so check that out. And we also have tons of
cool stuff. You can also check out the Monsters inside
(18:11):
of Me website. Yeah, Robert Lamb, Robert Lamb wrote some
ki cool stuff and actually we have to give him
a big thanks for pointing us, uh the in the
right direction for research on this this particular podcast. He
knows what he's doing. He's parasitastic. And of course, um,
how Stuff Works dot Com has tons of stuff on it,
and if you're interested, you can also read all of
our blog posts on it. There's like five million of
(18:33):
them and each one's better than the last. Yeah. That's
it for plugging, isn't it. So yeah, plug heavy, which
means buddy, it is time for a listener mayo. So, Josh,
I'm just gonna call this, uh, we're awesome because we
saved a woman's life. Yeah, this is crazy. It is
(18:54):
slightly hanky, but I'll take I'll take credit. Uh. Bonnie
from Boulder, Colorado wrote in, and Bonnie says, this, Hi, guys,
stuff you should know just saved my life. The facts
for these. I was driving home and had just finished
listening to your hyper Miling podcast. As a result, I
was only going forty miles per hour on a stretch
of highway where I usually go sixty. All of a sudden,
(19:15):
there was a pair of headlights right in front of me.
Some genius was going the wrong way in the same
lane of the highway as me. Short story even shorter.
I ended up facing the wrong way on the highway
thanks to some recent rain and some awful skidding and sliding,
But due to the late hour, lack of other cars,
and my slow speed, I avoided hitting anything. Who knows
if I would have had a head on collision if
(19:35):
I had been going my normal speed, But I do
know that thanks to YouTube and you're always enlightening podcasts,
I will never have to night. Many thanks. You're immensely
appreciative listener and fan. Bonnie of Boulder, Colorado, Thank you, Bonnie. Awesome. Honestly,
what if she would have been going twenty miles an
hour that could have made all the difference? Oh yeah, definitely,
even if it was just a fluke thing, I'll take credit.
(19:56):
Even if it wasn't fluke, we still picked up an
indentured servant for a lot. Yeah, and I personally I
think we should get a key to the city of
Boulder show. Yeah, I've always I've been England for one
of those for a long time. Key to any city,
No Boulder, Okay, Yeah, I think this is this is
our end for sure. Maybe a T shirt even sure? Yeah,
life and all I got is this lousy T shirt.
(20:19):
That's a good one. If you have any good T
shirt ideas or any instances of how Chuck and I
saved your life, you can send them in an email
to stuff podcast at how stuff works dot com. For
more on this and thousands of other topics. Is it
how stuff works dot com. Want more how stuff works,
(20:42):
check out our blogs on the house. Stuff works dot
com home page. Brought to you by the reinvented two
thousand twelve camera. It's ready, are you
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Josh Clark
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