- Oh hey there, welcome to What the Facts.
Our companion show to What the F 101.
My name's Jake Young
and I'm super jazzed about the parasite episode.
It's just full of really gross facts
about the wriggly ways that parasites
can get into your body.
And the violent horrifying ways
that they come out of them.
And I wanted to learn more.
And so in order to help us,
we've enlisted the help
of Kevin Lafferty,
who is a Senior Ecologist at the US Geological Survey.
Kevin, how are you doing?
- I'm doing great.
- How do you think we handled
the topic of parasites in the cartoon?
Like was there any glaring omissions
that you noticed?
- Well I want to say it's very rare
for me to work with somebody
that would actually spend the time
to animate wasps emerging from a caterpillar.
- So right off the bat I have to ask
what is like the juiciest, just grossest thing
you've personally witnessed in nature?
What fish is out there just getting
it's shit wrecked the hardest?
- Well you know the animation
of the Isopod taking over the tongue,
we see that, you know you open
this fish's mouth and there's these
two eyes inside that are looking
right back at you,
it's super super weird and disorienting ya know?
So that's that's a nice one.
- When the fish is cod, does have you ever
seen like the louse just kind of
like pull the ejector seat and just
scuttle away, or like once it's locked in there
it's there for life?
Well, it can dislodge if it needs to
but it holds on.
I mean it worked hard to get to where it was.
You know it's got those sharp little hooks
on the end of its legs and it digs right in.
- You know in the show,
we talked about Professor Foxtrot
laid out, how you know parasites are
part of the great web of nature
and that they are these beautiful
efficient creatures that interact with us
in this great swarm that we call life.
But I'm still having trouble buying it.
What is it about parasites that kind of
eek out people more than just
say a tiger chasing an antelope
or a virus kind of giving you the flu?
What is it about parasites
that have captured our imaginations,
specifically our nightmares?
- Yeah okay, so I think you are totally
right to be skeptical.
Even though this is entertaining
we can't ignore the fact that millions
of poor people have been impacted
by parasites like Malaria, Schistosomiasis,
Filariasis, even though that's not
part of our like day-to-day experience
or risk to us as privileged wealthy people
in Western countries.
We still I think have the remnants
of evolving with the threat of parasites
maybe think about it,
if you just imagine a tick crawling up your leg
it makes you want to scratch.
Or like I've got to hold my nose
to go into a porta-potty
because you know, the smell
of feces is an indication
that I'm at risk to be exposed to parasites.
And so we've learned or evolved
disgust as a response that helps us
keep from getting sick
and that's perfectly natural I think.
That doesn't mean that they can't be part
of the big happy web of life.
In fact, when we're on the same side
as parasites, we benefit from them.
- Wait I'm sorry, like are you talking about
how like in a bad comic book sometimes Superman
has to team up with Lex Luther?
Like where are we teaming up with parasites?
- Insect pests eat 40% of the production
of agriculture around the world,
and we can use pesticides to kill those bugs,
or we can rely on the natural enemies
like those parasitoid wasps
that eat caterpillars from the inside out.
- Speaking of stuff that kills bugs,
I found this online.
This is a cordyceps tea that was you know,
if you're a fan of video games,
you already know what cordyceps are.
They were the evil fungus that turned everyone into zombies
in the Last of Us.
Planet Earth had like a whole gross sequence.
Ugh it's the worst color.
Ugh that is not a good color.
Oh no, oh Kevin ugh, oh no.
That's that's another thing that really freaks me out is
you know I'm a conscious human being,
I'm a sentient life form, endowed with various cool stuff
like free-will and smart phones,
like how like can a parasite really
wriggle into my brain and control my mind?
- Oh for sure, I mean it might even
be doing so as we speak.
That's what's awesome about it.
I mean so okay, so let's talk about something
that I think we can both agree on,
which is that the rabies virus
messes with behavior right?
We see it in rabid dogs they are like
completely transformed, and we know
the same thing can happen to people.
We just don't freak out about it
because it's rare.
At least it's rare now in human history.
It didn't used to be rare in the past
there's other places in the world
where it still happens
actually pretty frequently.
I work with this much more common parasite toxoplasma gondii
and we know from really good, solid
experimental studies that this thing
will manipulate rodent behavior,
make the rodents less afraid of cats
but cats are key because the parasite
uses the cat as a final host to complete its life cycle.
And this parasite not only goes into rodents,
it goes into people and in some countries,
most everybody in the country is infected, right?
And so the parasite doesn't know its not in a rodent brain,
it's in a human brain
it still tries its tricks that work on a rodent.
And so we know that this parasite can cause
subtle changes in human personality
and what makes that really interesting
is when you have a parasite that
can affect personality and if it can affect
most of the people in one country
and hardly any people in another country,
then maybe that explains some of this
cultural variation that we see around the world.
- I'm not gonna lie, when they first
you know, when there was those first
those headlines about toxoplasmosis on the internet,
I was really hoping that was going to be
just one of those things that like a year
later they'd be like no they tried it again
nevermind you're fine, everything's fine.
And I've owned way too many cats to not be freaked out.
- Yeah, yeah I mean there's a decent chance
that you are infected.
I've had myself tested before I wrote my papers
on it just so I could have a clear perspective on it.
At the time, I wasn't infected so.
- Okay, okay, stop bragging alright.
It's oh oh I'm a cool,
I'm a cool adjunct at a major college,
I do environmental work at the time in history
where it's most needed.
My brain isn't full of monsters, good for you.
- I don't have to share co-authorship
with the parasite in my brain that way.
- How does like on an evolutionary perspective,
how does a creature like figure that out?
Because sometimes it's really specific.
I think this is another you know nature
documentary call out,
trematodes that would go into a snail and like
literally turn their heads into giant
pulsating like signals for birds to see,
so that they can get it,
literally go from the mud of the earth into the sky.
- Natural Selection operates by incredibly
inefficient trial and error.
But, if you do that over millions of years,
then you can get to some pretty cool places.
Like, I mean you take the eye or wings
or a barnacle's giant penis,
you don't get there in one millisecond
it takes lots of trial and error to get there.
So parasites are the same in this
like the example of the Foxtrot's frog
that's sprouting all these weird limbs.
That parasite has lots of relatives
and its ancestors too that just
infected the muscles of frogs, okay?
Nothing special happens in most of those cases.
But, this particular parasite by accident
ended up in the limb buds of tadpoles.
And being there, they can mess with
the production of new legs.
- It was multiple legs,
they make just legs where legs shouldn't be.
- Yes, exactly.
And so when that frog climbs out of the pond,
it's more likely to get eaten by a raccoon
or a bird and that is the final host
of that parasite and that final host
helps move that parasite to the next pond.
Otherwise, you know it wouldn't
be able to complete its lifecycle
and it would get stuck.
So those sorts of adaptations,
we see them all the time in parasites
and we think that they're so unusual
but I think the way to comprehend it
is that trial and error over millions of years
gets you to some pretty strange places.
- I, you know, I need to settle my nerves, let me just.
Oh that is sour dirt.
Oh God!
(inhales sharply)
Oh okay okay.
It's like vegetable oil stock that went bad.
- Yeah well I mean eating the spores is safe.
You just don't want them to grow into your body.
Through your skin.
- Wait, no that's the bug spore
they won't know what to do in me.
Yeah yeah that's fine.
Kevin thank you so much for joining us
and how can we follow your work
and support it in the future?
- Just you know think about parasites,
keep spreading the message.
That's what we wanna get people to know
about these hidden creatures inside of us
that actually are pretty cool.
- Kevin, that sounds like something
a parasite in your brain would say
in order to spread to more hosts.
I suggest you get re-tested.
- I will get re-tested.
This is an excellent idea
but that could be the parasite saying that too.
- Well thanks again Kevin.
Well that was existentially terrible.
Hey, you've been watching What the Facts
and don't forget to check out What the F 101
on dropout.tv
Next week we will be covering
self-experimentation and all the gross ways
that it's been used to advance
the medical community.
And hey, speaking of self-experimentation, cheers!
Ugh, its like a portobello nightmare in my brain!
This was a terrible idea
we're not doing this bit again.
That was bad for my mouth.
We're done right, we're done?
Just get the...
I need water!