March 16, 2023 • 42 mins
In this podcast episode, the hosts delve into a fascinating paper published in Nature Communications about Toxoplasma gondii, a single-cell parasite that can alter the behavior of its hosts. The study focused on cougars and wolves in Yellowstone National Park, where their territories overlap, allowing for the spillover of the pathogen. The hosts discuss the importance of Toxoplasma gondii, which can infect warm-blooded animals, including pets, livestock, and birds, and is zoonotic, meaning it can be transmitted to humans. They also highlight that the direct host is a feline, and everything else is an intermediate host.
The hosts discuss how the parasite can affect behavior, making prey animals bolder and more prone to doing risky things, which puts them at risk around wild cat predators. They compare this subversive style to rabies, where herbivores become more docile when they infect, making them easier prey for predators. The hosts point out that Toxoplasma gondii infects around two billion people in the world, with a high prevalence in the population, but most people deal with the infection without developing any clinical symptoms or disease.
The episode is a fascinating deep dive into the science of Toxoplasma gondii, with insights into its behavior-altering effects and the dangers it can pose to both animals and humans. The hosts also touch on the clinical aspects of the parasite, highlighting the guidelines for screening and treatment in immunocompromised individuals. Overall, it is an engaging and informative episode that will appeal to anyone interested in microbiology, parasitology, and infectious diseases.
Thanks for listening to the Infectious Science Podcast. Be sure to visit infectiousscience.org to join the conversation, access the show notes, and don’t forget to sign up for our newsletter to receive our free materials.
We hope you enjoyed this new episode of Infectious Science, and if you did, please leave us a review on Apple Podcasts and Spotify. Please share this episode with others who may be interested in this topic!
Also, please don’t hesitate to ask questions or tell us which topics you want us to cover in future episodes. To get in touch, drop us a line in the comment section or send us a message on social media.
Instagram @Infectscipod
Facebook Infectious Science Podcast
See you next time for a new episode!
Mark as Played
Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
(00:00):
When I think of the greatmajestic predators in North
America, I think about wolvesand cougars. But what if I told
you that those predators aresusceptible to some of the same
parasites that infect the orangetabby currently sleeping on your
laptop and demanding fancy feastor Meow Mix or whatever it is
this week? You guessed it, we'retalking about Toxoplasma gondii.
A the parasite that keepspregnant women from changing
(00:21):
litter boxes. But here's thekicker. A recent study found
evidence that this parasite mayincrease the odds of an infected
wolf becoming pack leader.
Crazy, right? We have a reallyinteresting story coming up
next, so stay tuned.
(00:43):
Welcome to the infectiousScience Podcast.
This is not just another SciencePodcast Nope. Infectious science
is produced by a team from theUniversity of Texas Medical
Branch and the Galvestonnational lab
where we study some of the mostdangerous viruses on the planet.
Our goalis to inspire future scientists
towards a career in science witha focus on one health, one
health one planet. That's right.
(01:04):
One of the approaches publichealth threats by examining the
connections between people,plants, animals and the
environment. We all sharethis show we'll explore how one
health is your health. So sitback and learn something
infectious science whereenthusiasm for science is
contagious. Hello, listener. Hi,everyone. Welcome back to
(01:29):
another episode of infectiousscience podcast here and UTMB,
the galvus National Lab. I'mseated here with my friends and
colleagues, Dr. Daniel Sweetnam,Dr. Dennis benta, and Matt
Dasho. And we're doing somethinga little different today. And we
need to know if it works. So ifyou like what we're doing today,
we want you to tell us in theshow notes, leave a comment, hit
(01:49):
the like button, whatever it is,give us a follow tell a friend.
And we're going to link to thispaper in the show notes. What
we're doing today is we'retalking about a paper,
a little bit of a journal club.
Yeah, journal club.
And we're all going to talkabout this paper. Danielle, you
brought this paper, it was socool to read. I've never read
about this topic before. So itwas really interesting for me to
(02:11):
delve into it. Tell us what thispaper is.
So this paper is a reallyexciting paper and it was
blowing up all over scienceTwitter a few months ago when it
came out. And it was publishedin Nature, which is a really
high impact journal NatureCommunications. And it's about a
parasite that you may have heardof, it's texel plasm, gone di
and this parasite. They'relooking at it in cougars and
(02:33):
wolves and discovering that itmight be altering the behavior
of wolves. And even alteringpack dynamics. Even if the
parasite infects just a singleWolf, it can change that
dynamics of the entire pack. AndI just think that's so exciting
that something so small can havesuch an incredible impact. And
that's kind of to me, just likethe epitome of why microbiology
(02:53):
is so cool.
Yeah, this is super cool. So Idid see this paper on Twitter as
well. But why did you reallylike picot? And and like, what
captured your interest? And whydid you select this paper?
Well, most of what we know aboutToxoplasma gondii. I think most
of it we know about in preypredator dynamics, and we'll
(03:15):
talk about that a little bitlater. And Yellowstone National
Park is this really interestingarea. And that's where the study
is being done, where wolves andcougars, their territory is kind
of overlapping. And so we havethis really exciting multi
predator multi carnivores systemthat we don't normally see that
wolves and cougars are usually,even though they have the same
(03:36):
prey are usually kind ofselecting to be separate. So
this really interesting area isallowing for this interesting
spillover of a pathogen, which Ijust think is just this really
interesting area and I will kindof want to go to Yellowstone
National Park. So it's a niceplace to think about.
Yeah, I've never been either. Solistener if you're interested in
(03:56):
sponsoring a an infectiousscience trip out to Yellowstone,
we know take Venmo Cash App,Zell. So Dennis, you're the vet
tell us about toxic so I onlyknow about it and humans, right,
we learn about and I've takencare of folks who've been
infected with toxo mostlyimmunocompromised people, people
(04:17):
with HIV AIDS usually advanced,the HIV they're
immunosuppressed. They have lowimmune systems, they can't fight
off viruses and bacteria likesomeone who's got all of their
white cells and then we alsohear about it in pregnancy. You
know, those don't clean the catbox, you know if you're
pregnant, because you mayaerosolized the feces and
inhaled it or be exposed to it.
What is this pathogen and whatdoes it look like in animals?
(04:40):
You know, in vet school, you'veToxoplasma gondii is obviously a
staple that you have to learnabout, but not so much because
it causes you know, devastatingdisease and animals but
obviously, because it's azoonotic disease and can be
transmitted to humans, but we dolearn about it. Obviously, cats
being the main host and know alot of Veterinary Medicine.
focuses on domestic animals oncats and dogs. But it's not just
(05:03):
house cats, right? No, that'sThat's correct. Toxoplasmosis is
a disease cause you know, as wetalked Toxoplasma gondii i and
it theoretically can infect anyor many warm blooded animals,
including pets, livestock birds,and obviously people so I think
the reason why we focus on catso much domestic cats is because
(05:25):
they live in close closeproximity to us and a big one
health question humans and petsand close proximity and, and
human infection can occurthrough domestic cats. And I
think that's why this is part ofthe education and why we learn
about this so much. And, youknow, typically most infected
adult cats, they appear healthy.
However, some cats may developpneumonia, liver damage or some
(05:46):
other health problems, but inmost of the time, it's really
avert, there's no signs ofillness in cats, maybe if they
are infected, they arelethargic, loss of appetite, but
it's not really just a big dealin vets medicine.
So some people are some peoplefrom cats being people, cat
(06:07):
owners. So some cats, that meando they manage? Some of them
don't have any symptoms at allright? I mean, they
can most of them. Yeah, most ofthem. And if you have an
immunocompromised cat or akitten, for example, feline HIV,
right F IV that canimmunosuppressed, the cat, then
the parasitic infection has nocontrol or is not controlled,
(06:28):
and then we'll just go rampid inthe cat and then the cat will
get sick.
Okay, so I'm hearing why it'simportant for cats certainly
know why it's important forhumans. So Daniel, when you were
reading this stuff, whatprompted these guys to do this
study, what was the main problemthey were trying to understand.
Solet's back up a minute, because
there's a couple of things Ireally want to emphasize. Okay,
emphasize emphasize this, thisis a protozoan, just a single
(06:50):
cellular parasite. And likeDennis said, It infects warm
blooded animals in general, thereal big important key here is
it needs some type of feline toreplicate. This is really,
really critical part of itslifecycle, the direct host is
some kind of Feline, everythingelse is like an intermediate
host. And when it spread from ananimal that's not a cat, it
(07:14):
escapes the intestinal lining,and it can form me cysts, and
muscle and brain tissue. Andthere's a lot of evidence that
it could affect behavior. Now,the way it's spread is by
basically three ways you can bespread by consuming the parasite
eggs, but that can only comefrom one of the cats, and it can
be through eating the cat, or itcan be through coming in contact
(07:38):
with feces of the cat or thescat or something that's been
contaminated with it. The otherway you can contract it is if
you eat infected meat, anythingthat's been infected with the
parasite. So it can be aninfected cat or an infected dog
or cow or anything like that.
But the really important thingthat you have to remember for
(07:59):
the rest of the story is it'sonly replicating in cats, or
cougars and our story. And soyou use a couple terms there. I
just want to like clarify. Soyou said direct host and an
intermediate host right? So canyou kind of flesh those out a
little bit? Because I in myhead, I was actually reversing
them. I was like, Oh, theintermediate host must be the
one where it's replicating. Andthen the direct one is where
it's reversed,right? Yeah. So the direct host
(08:21):
is where it's replicating. Andthat's cats. Everything else is
an intermediate host, you canget it from eating the
intermediate host. But you'renot going to get it from coming
into contact with the feces ofthe host.
So are you saying in theintermediate host says no
replication in the none at all,no. amplification of the
(08:44):
parasite in the intestine?
No, it just kind of travels fromthe intestine to kind of muscle
or brain tissue and formsassists to protect itself and it
goes chronic, it kind of justhangs out and doesn't do
anything unless you'reimmunocompromised. And then it
can start to cause some kind ofinflammation in some disease,
but it will just hang outforever indefinitely, but not
(09:04):
replicate.
And I'm against scare tactics.
I'm against just anybody knowsme. I don't like people would be
scared. But the numbers thatwe're seeing were pretty crazy.
Like 2 billion people in theworld. Probably infected. Yeah.
Okay. That's a lot a lot. Right.
Idon't know the exact number. But
it's a very high prevalence inthe population, which is
something we don't always thinkabout. Right?
(09:25):
Yeah, well, probably becauseit's not causing any disease in
most of those people. And inmost of those animals that's not
causing any disease. Yeah, Ithink this is something that the
major take home messages I wouldsay is that a lot of people get
exposed to toxoplasma and theywill deal with the infection,
but they will just seclude theparasite and there's no clinical
signs as no threat to help inany way. So that's the most
(09:48):
common outcome of an infectionor an exposure with toxoplasma.
I think that's kind of likereally something we need to
emphasize.
Yeah. Okay. So that's kind ofThe basics of the parasite. But
what's really, really cool isthis kind of idea that this
little micro unicellularorganism is there's a lot of
(10:10):
evidence that it can changebehavior, even in these hosts
where it's not doing anythingelse, and it's just hanging out.
So, for example, in rodents, andmonkeys, and hyenas, it all
really makes them more prone todo risky things. In rodents, it
makes rodents less adverse tohouse cat urine, and in monkeys
that makes them less averse toleopard urine. And in hyenas
(10:31):
specifically, it makes them alot more bold around lions,
right? These are all reallydangerous things, this increases
the likelihood that theseanimals that are infected are
going to be around a wild catthat can eat them, and then that
cat would become infected. Sothis parasite makes the animals
bolder, these prey animalsBoulder, puts them at risk, and
(10:54):
put some around these catpredators and then kind of
perpetuates itself. And thatkind of interesting kind of
subversive stylealmost sounds a little bit like
rabies, right? Like where youhave herbivores that all of a
sudden become more docile whenthey infect an easier prey for
predators. Correct. Do you wouldyou agree? Yeah, for sure.
Yeah, it was so interesting,Danielle, because you sent me
(11:14):
down a rabbit hole when you sentthis paper because I started
thinking, oh, man, like, I onlyknow the clinical part right
out, I know, the dose ofantibiotic you're supposed to
give I know when you're supposedto, you know, the guidelines for
HIV say you're supposed toscreen for talkshoe. And when
you're supposed to treat and soI know those things, but I
didn't know anything else aboutwhat toxic do to behavior. And
(11:36):
as I started traveling down therabbit hole, into the
literature, I found severalpapers, right in humans
describing that actuallytoxoplasma infection is
associated with things likeschizophrenia, there was a paper
that described that people whoconsume alcohol were more likely
(11:57):
to have behavioral effects, ifthey were toxic positive, found
one paper that was done onuniversity campuses, it was kind
of a funky study design, butthey looked at college students
and found that people who werebusiness majors were 1.4 times
more likely to be toxo IgG.
Positive. So.
So compared to what biologymajors, right.
(12:20):
So I don't know what that saysabout all of us. I was a music
major. Sonow I think all these papers are
really interesting. And I thinkthis has been a theme for a long
time, what toxoplasma can do tobehavioral changes. And it's not
a new theme, right? I mean, thiswe know this from the animal
kingdom, how parasites canmodify, and behavior and so on.
I'm still skeptical, though,what is the likelihood of 1.4
(12:43):
times really mean?
Right, the paper I saw is thatit looks like people that have a
chronic infection with toxo haveincreased testosterone and
dopamine. So there's an ideathat maybe with the increase of
those two hormones that thatmight lead to risky behavior.
But what does risky behaviorlook like? There's a lot of
(13:03):
types of risky behavior. So itmight be something that's just
if there's a behavioral changegoing on in the human
population, it might be reallyhard to quantify, because risky
is super subjective, right. Andit's easy. When we talk about
the paper they define for riskybehaviors that they're going to
lookat. Yeah, but I think also more
like the biostatistics like 1.4%times more likely, is this very
(13:26):
high, orit's just hard to do prospective
studies. We can't like infectpeople intentionally.
In fact, freshmen, and then seewhat major
letters from iOS x community,yeah, on this, we're not
suggesting this, please don't dothat. But it was interesting to
me to see that there were theseat least correlative studies in
(13:49):
the human literature saying,well, actually suicidal
behavior, schizophrenia, whichis heavily dependent on
dopamine. So these were alteredby the presence of this
parasite, or at least haveantibodies to this parasite. And
so very, very, very interestingthat it could potentially have
somenose to humans. Maybe in a few
years, when we talk about mentalhealth, we'll be looking at
(14:11):
infectious diseases a little bitmore closely and associated with
that, but yeah,I know a lot of infectious
disease doctors that would bevery pleased to know they
they've their their field is somuch so relevant in so many
ways. Yeah. Infectious diseaseand cancer, infectious disease
and hypertension, infectiousdiseases and heart disease, you
know, infectious disease andmental health. We know from
COVID-19 that people who aredealing with post acute COVID
(14:34):
syndrome or long COVID aredealing with a lot of mental
health side effects. Right.
So what happened in the paper?
Let's talk about the papersorry, tangent go over. Okay.
So we talked about all theseother studies where toxin has
been studied, and I mentionedbefore, most of the studies, at
least in the animal kingdom,were looking at predator prey
(14:57):
dynamics, but that leaves a lotof other kind of directions up
for questions. And in theYellowstone National Park wolves
were driven out of that area inthe early 1900s. And then were
reintroduced in 1995, likebetween 1995 and 1997. And since
that time, there has been a tonof effort to monitor their
(15:18):
health and behavior andsomething really similar
happened with cougars, althoughthe the Cougars reintroduce
themselves, but still, there'sbeen a lot of monitoring
Cougars are gonna go wherethey're gonna go. In this case,
don't try to tell a cougar. Heor she can go I
don't know why that's funny. Ifeel like something about it is
funny. Okay, so yeah, theseanimals that were excluded from
(15:40):
this area and reintroducedWilson Cougars both prey on
smaller animals, but they'rerarely found in the same
location, except for here atYellowstone National Park
specifically in the north. Mostof the Cougars kind of colonized
the the northern part of thepark where there's lower
elevation. But in the winter,the bison and elk and mule deer
(16:01):
migrate down elevation into thisnorthern part of the park. And
when the prey animals migrate,well, the wolves follow. So for
this period of time in thewinter, there's this really
solid overlap between the two.
And the Cougars just so happenedto be carriers of toxo,
specifically, and it's actuallyincreasing quite a bit between
1989 and 2004. About 45% of theCougars in that area that were
(16:23):
surveyed were toxic, positive.
And more recently, a survey thatwas done in 2016 to 2020, that
number increased to 73% of theCougars in this area are toxic
positive. So boom, here's thisreally great opportunity, the
samples that have beencollected. There's data about
behavior, there's data, there'ssamples, serology samples that
(16:45):
have been collected, this is agreat area to really leverage 26
years worth of data and samplesthat were collected to look at
this interaction.
So Daniel, when you say a toxicpositive, so in technically
term, in technical terms, theyare seropositive, they have
antibodies against Yeah,Toxoplasma gondii. I do you
(17:06):
know, is the the sero positivityautomatically a sign that the
infection has taken a footholdin the person or the animal?
Well, I think it's assumed thatevidence of prior infection
indicates current infection,because I think what's known
about toxo in general is wedon't clear the infection, the
(17:27):
virus creates cysts in the brainand the muscle tissue and
persists for the lifetime of theanimal. I haven't read anything
about if there are any animalsthat are able to clear the
infection. So I think if you'veever been infected, it's
assumed, at least in this study,and other studies I've looked at
the infection is still there.
Right? So that makes sense. Butcan we infer that only because
(17:50):
it's positive that there's somebehavioral change automatically?
No. But that's what they lookat. So they had two goals.
First, they want to determinebecause not all the wolves in
the park were living overlappingwith cougars. So they were
saying what kind of factorscontribute to infection and
wolves. And the second thingthey're trying to look for is
does infection alter wolfbehavior? So there were two
goals?
(18:10):
That was really, really cool.
And so gosh, I can't imagine howthey did that. Did you get a
sense of like how they fancymath behavior? Yeah, it's really
was a lot of math. Yeah. A lotof math in there.
Yeah. So for the first kind ofquestion to determine the
factors that affected thelikelihood that the wolves would
become infected with toxo. Youcan't just say, were they living
(18:32):
in the same area, right, becausethere's a lot of other things
that can contribute. So age ofthe wolf sex of the wolf,
whether or not the wolf was apack leader or not the coat
color of the wolf, things likethat. And then what poor portion
of their territory wasoverlapping with the Cougars. So
men kind of accounted for thatusing a variety of like
statistical tools andmathematical modeling. And what
(18:54):
they found for that question wasthat the only feature they found
that was significant was whetheror not the wolves shared
territory with the Cougars. Andthe the wolves that had a lot of
their territory like highoverlap with the Cougars were
nine times higher odds of beinginfected with toxo.
So we this basically showedthese these environmental
(19:16):
changes happen, the wolvesmigrate down to share kind of
the same habitat as the Cougarsdo. And because of this overlap,
we definitely see an increase intransmission from the direct
host to this intermediate hostwhere the thing kind of find its
end pathway.
Talking about transmission. Youknow, I think all of the
(19:37):
listeners who own dogs know howdogs sometimes even pick up cat
poo, right? I think we've we'veall seen this. One fun fact that
I found doing my research onthis is that the the O says from
Toxoplasma gondii I theyactually need to spend 24 hours,
maybe even up to five daysdepending on environment. mental
(20:00):
conditions in the environmentbefore they can become
infectious. So it's not that youfind feline stool or something
like that, and then it'simmediately infectious. So it
takes some time for the the oldcysts to mature for lack of a
better term to becomeinfectious. So I know this is
not really covered in thisarticle, but
(20:20):
so it can't be the fresh stuff.
Fresh juicy stuff. It's gotta bethe rock hard, you know, been
out there for a little while.
Those are that's the realis so to say so full anything
about seasonality in this paper?
And do you think theyspeculate they say that they
don't think it is infected prey?
So they don't think it's theinfected elk or deer? And they
(20:42):
did some surveillance? And Ithink elk it was and they didn't
really find any seropositive.
Elk are a very small portion ofseropositive elk. So they
suspect that it's direct contactwith the Cougars, or the Oh
sites in the scat, I guess. Butin the winter, I don't know
maybe there's like a freeze thawthing going on, or could even be
contaminated water, orcontaminated vegetation or
(21:03):
something. Or I mean, they couldeven be eating a burger. I don't
really understand thosedynamics, like do wolves. Would
a pack of wolves prey on acougar? Or would that be the
other way round? It'll getemboldened. Yeah. Maybe because
if a wolf were to eat a cougar,or they came across a dead
cougar or something, and Dennisthe wolves do that,
(21:26):
you know? Sure. Yeah. I'm justamazed by the seropositivity
level of what was it? 45% orsomething like that. So there
must be ongoing transmissionwithin the Cougars? Well, yeah.
And also to spill over to thedogs. Dogs to the wolves. So
sorry. Well,so what else did they find? So
that was their first study?
That was their first question.
age, sex, social status and coatcolor did not affect
(21:48):
transmission of toxic to wolves,but overlapping territory did.
The second question was the bigone that kind of cool one did
toxic infection alter wolfbehavior? So here were they
identified four risky behaviors.
The first one was becoming PACleader. They consider that a
(22:10):
risky behavior because there'ssome kind of violence involved
in that, as I understand it'squite a violent transition like
a fight. Is it like a fight tothe death? Or is it or somebody
retreat or somebody? Yeah. Soyou would expect that to be
that's obviously a riskybehavior.
I mean, going into any kind ofleadership politics, this is
risky behavior. You know, you'reputting a lot of the comfort of
(22:31):
your home anonymity. You know,these wolves are just putting
themselves out there.
Yeah, maybe that should be astudy. Yeah. Parasites among
political leaders? Oh, gosh,don't get us started on that.
There's so many jokes there.
There's like you can take itdown.
Yeah, okay, let's remainfocused, bringing in the second
(22:52):
risky behavior was dispersal. Sobasically, this is when a wolf
leaves his pack or her pack andnever comes back. And usually
this is, this is really risky,right, because you lose the
protection of the pack,particularly in the harsh
environment of winter. Butgenerally wolves do this, and it
increases the likelihood thatthey'll find a mate. Or maybe
they can come across anotherpack and try to challenge that
(23:13):
pack for leadership. Sodispersal is another high risk
behavior in wolves. And then theother two were related to
people. One was habituation,which is how likely the wolf is
to approach people or a vehicle.
And then the the final riskybehavior was Did they die as the
result of interaction with ahuman. So those were the four
risky behaviors that theyassessed. So first off, they
found that of the wolves thatdispersed, they were 11 times
(23:39):
more likely to be infected withtoxo. So that's a pretty big
increase, and your willingnessto disperse. That's pretty
incredible. And this is kind ofreally the thing that stuck out
the odds of an infected wolfbecoming a pack leader was 46
times higher in a seropositiveinfected wolf than an uninfected
(24:00):
Wolf. So that's almost 50%Higher. So that's huge. And just
imagine you've become leader ofthe pack. And now you're the one
taking risky behavior, andyou're maybe engaging your whole
path in this new risky behavior.
And just think of theimplications for like social
learning and new kind of wolfcubs that are being born into
that pack. That's a riskierpack. But the two things about
(24:23):
humans are the two risky thingsabout humans, they didn't find
any statistically significantdata. So that is good. And it's
not increasing the likelihoodthat the wolves are going to be
approaching people or somethinglike that, because
that's quite risky for them,right? Like that's, yeah, people
are probably scared of that.
We're scared of wolves, but it'sprobably the biggest risk to
them.
Right? The thing is, is theyeven acknowledge it that their
(24:44):
sample size for that was very,very small. They didn't really
detect much interaction betweenwolves and people. So wolves
that are infected might be morelikely to approach people but
I'm really justa thought here on the side. Not
crucial, but I think that's whenit comes to rabies education.
And we always teach people thatif you find a carnivore or
omnivore that's very docile thatthis could be a sign of, you
(25:06):
know, some form of infection orrabies infection. Right. So a
wolf approaching being way morecomfortable with the human could
trigger somebody you think, youknow, we need to shoot the wolf
because it's you know, hasrabies.
Interesting. Yeah. No, that's,that's fascinating. Danielle, as
I was reading that I was just,again, harkening back to that
(25:29):
human side thing, we'redefinitely see differences in
behavior that's caused by thisparticular parasite. So very
cool. Yeah, it's so cool. It'sso fascinating.
What do you think are theimplications for this? They've
done this really elegant study,they've really, I think, shown
something. And certainly thathas been shown experimentally in
(25:52):
controlled conditions, in rats,and as you mentioned, in some
other animals, that there arethese behavior changes that
happen with Toxoplasma gondii,infection. And now they've shown
in a real world environment, andwith control of a lot of
variables and a lot of data,that this is independent of
other things. This is acontributor to not only changes
(26:16):
in the individual's behavior,the individual wolves, but the
pack behavior, like you pointedout. So where do you think this
leads us? What are theimplications for this? Where
does it go for maybe otherdiseases? I always think, you
know, one, health is not alwaysabout human health, right? It's
about interconnections humananimal environmental health. And
so we selfishly sometimes lookat animal studies as like, some
(26:37):
excuse to apply it to humanpopulations, right? Do you think
we're there yet to be able toextrapolate that? Or is it just
another line of investigation?
So I don't know, maybe it'd bebetter to ask you those
questions as a physician,because for me, what I'm
thinking about is how does thisaffect park management? How does
this affect wildlife management,the overlap in these two
(27:00):
predators is kind of somethingthat isn't really seen anywhere
else. And it's seen in this areawhere the wolves were
artificially reintroduced intothat, and something that we
looked more closely at and maybeshould look more closely at
moving forward. And the impactthat this could ultimately have
on the wolf population, right?
This is all happening during thewinter. And this is also just so
happens to be when wolf matingseason and whopping season is
(27:22):
going on, this is increasing thelikelihood that a wolf will
become infected while they arepregnant and carrying cubs. And
this is going to increase thelikelihood that it's transmitted
vertically from mother tooffspring. And if just like
within humans, there can bereally extreme damage to the
fetal Wolf, if the mother isinfected. So will this have a
(27:46):
long term decrease in the wolfpopulation overall? Will it
increase the likelihood that thewolves will die? Because they're
taking a risky behavior? Doesthis kind of interaction with
Cougars put them at risk inother ways than just kind of the
predator predator carnivore,carnivore interactions? So yeah,
that's really what I'minterested in, and what I'm
going to be looking for in thefuture.
(28:08):
Well, if the authors arelistening, please continue to
collect data for the next 26years.
And what an amazing example ofwhy it's so important to collect
data for long periods of time,right? The study has 26 years
worth of data. Oh, my gosh, it'sincredible. How, how old were we
26 years ago? You know,obviously, the people that did
this work, were not the peoplewho started it. So what kind of
(28:30):
foresight went into this?
Absolutely. I think this is avery elegant study. I think it's
just amazing paper. I feel likeI'm the Debbie downer here, the
critical voice. But one thingthat I just have a really hard
time wrapping my head around ishow does assist really leads to
(28:50):
behavioral changes. I mean, youtalked about different levels of
dopamine, different levels oftestosterone. And I think that
makes a lot of sense. But fromwhat I remember from
histopathology, back in the day,those parasites those cysts,
they randomly occur in thebrain, and not in specific
(29:10):
regions of the brain. What youwould expect if you think about
the hypothalamic, pituitarygonadal axis, or whatever it's
called, right? So where you haveto have a lesion in the
hypothalamus, and that willmaybe change the expression of
GN HR or something like that,right. And last, but you know,
(29:31):
like the axis that triggerstestosterone production, so I
just don't understand how arandomly placed cyst will lead
to an increase in testosterone.
And that's, I think, forendocrinologist answer and
there's probably a couple ofexperimental papers that
describe that. We do know that alot of infections either by way
(29:54):
of a direct effect of thepathogen the infection happens.
Thing sets up shop, it can causethe secretion it can induce by
secreting its own chemicals thatcan cause the secretion of
certain hormones, orneurotransmitters like dopamine,
but also possibly theinflammatory response. Right? So
maybe it's a question of how ourbodies are responding to the
(30:17):
pathogen. So it's thatconnection. And I can't speak
intelligently about either ofthose two things. But I would
say those are interestingquestions that for me would come
from this.
Absolutely. And I think that wealways have these discussions in
the one health realm that's whenit comes to one health, we talk
about policy and have theseframeworks and but I think
what's often missing missing isone health research. And I think
(30:41):
this is such a good example ofOne Health Research, where you
have the behavioral changes. Andnow let's dive into the
molecular side of things. Let'snow understand the pathogenesis
behind this. And I think thatis, by definition, one health
research, and I think thereneeds to be more effort on this.
I think that would be maybe thenext paper we can read, we'll go
(31:03):
look and see if any of ourlisteners know of any papers
that talk more mechanisticallyabout how parasites or viruses
can alter expression of hormonesor neurotransmitters. Yeah, I'm
sure there's people I'm surethis is an area of research, not
my area ofenvironmental peace. You know, I
used to live in Botswana,Southern Africa. And there's
(31:24):
this lovely Game Reserve, rightacross the border from Botswana
into South Africa. That's calledthe Monday QA game game reserve,
and shout out to Tao lodge wherewe usually stay and bow in the
local language means means lion.
So this particular region of thepark that we stay in is full of
lions, and in fact, becomingquite a big problem in the park,
(31:47):
because not only are they veryterritorial and battling each
other, but they also compete forfood sources. And over the
years, South Africa, instituteda lot of safety policies for
wild animals. And so they'vealso become a destination for
rescue lions. And so as the lionpopulation has, in some ways,
(32:08):
naturally, and in some waysartificially increased in this
enclosed game park, but it'sstill a game park, I wonder
about, you know, these arefeline animals, right? So how
much toxo is out there? And whatare we gonna be seeing maybe
very bold giraffes, oh, that arejust coming up to two lions,
two lions and saying, Hey,Scott, maybe
(32:31):
they're herbivores, but youknow, that can cover the plant
life. And so I, you know, youreally do wonder about not only
natural increases in thesepopulations that can be
replicated hosts for thesepathogens, but also the dynamics
of when humans introduce them.
So human behavior, once again,it's not always terrible. We're
doing something good, right?
(32:51):
We're trying to save lions,right. But there's always
potentially downstreamconsequences to be considered.
So Matt, for our listeners thatdon't know too much about
toxoplasma. What can you tell usabout congenital toxoplasma
infection and pregnant women andcleaning the litter box and so
on? Do you have some advice? Andcan you tell the listeners a
(33:12):
little bit about that?
So I can't say muchintelligently because I'm not an
OBGYN. Boy, the last time I tookcare of a pregnant person was a
long time ago. But generally,what we know is that it causes
congenital fetal malformations.
It's one of the torch infectionsthat is associated with fetal
abnormality, whatis what is torched mean?
(33:33):
So thanks for asking thatDennis. Torch infections are
toxoplasma others which includessyphilis, and hepatitis B,
rubella, cytomegalovirus, CMV,and herpes simplex. So that's a
group of infections that we'realways keen to prevent, in
practice, how do the babiesbecome its vertical, so these
pathogens are able to traversethe placenta. So as you're just
(33:57):
stating, as your fetus isgrowing inside the uterus,
there's this really beautifulapparatus, that's the placenta
that it's not much to look atwhen it's on the outside on the
inside. It is just a gloriousnetwork of blood vessels and
signaling and it's basically themain organ that filters maternal
blood for any kind of adversethings and make sure that
(34:19):
whatever is coming to the fetusis going to be nutritious, and
there are certain pathogens thatevade that placental barrier.
So Danielle, what would you sayif a pregnant woman wants to
surrender her cat because she'safraid that she could get
toxoplasmahave your husband take care of
the cat. So the primary risk topregnant women would be in
(34:39):
dealing with the cat excrementand cat feces, so cleaning the
litter box or if you have anoutdoor cat and you're gardening
or something like that, or ifyou're living around a lot of
stray cats so there's certainways that you can protect
yourself from that kind oftransmission. You can wear
gloves while you're changing thelitter box, you can ask someone
else in your family To changethe litter box, you can have
(35:00):
your cat, go stay with a friendduring the time that you're
pregnant and then come back andlive with you. So there's
definitely ways that you cankeep your cat in your life after
you're pregnant, and be safe andconfident that you're not going
to get tuck. Soyeah, and it's not like a
guarantee, right? It's a risk.
(35:20):
It's like anything your catmight not have toxo. And so I
think, you know, you don't wantto cause this widespread panic
that you know, every time youget near a litter box, you're
gonna be at the risk of gettingtoxo I think it's just important
to know, these are risks that ifyou have the ability to have
someone else, change the litterbox, great. If not wear barrier
protection, wear masks, just besafe about it. We tell pregnant
(35:41):
women not to eat unpasteurizedraw cheese, right for risk of
listeria infection. We will talkabout safe sex, we talked about
a lot of things to try toprevent potential diseases that
could harm the fetus. So I thinkit's just one of many, but it
doesn't mean that get rid of thecat is probably overkill.
And you can still go visitYellowstone National Park if
you're pregnant.
(36:02):
Absolutely. Just stay maybe, youknow, just go away from the
calcified feces of the Cougars.
Right? Those are those are not,those are the next.
One thing I also wanted to pointout when it comes to the
potential risk of pregnant womenacquiring the infection from
cats. Cats don't shed toxoplasmaconsistently, they will only
(36:26):
shed the old cysts or the eggsin their feces for approximately
10 days after the initialexposure. Oh, interesting. So
it's not that a cat you own acat in its lifetime, it will
just shed Oh, is this or eggs,toxoplasmosis. It's just up to
10 days after the initialexposure. So the question is,
(36:46):
you probably don't know if yourcat has been exposed and when
and will be exposed. But that'sdefinitely not the concept of
lifelong shedding.
Interesting, interesting.
And if what you said before istrue, Dennis, which is that it
takes some time in theenvironment for toxo to develop
the ability to infect a newhost, then I mean, as long as
(37:09):
you're cleaning up fresh stuff,then changing the litter pretty
frequently. Shouldn't that bepretty good? That'd be a pretty
good practice, I would say. Soit's just can't be old rock hard
stuff, right?
Yeah. And if you have an indoorcats, and you know that the cat
is not going outside eatingrodents that are infected, or
something like that you at leasthave a grasp on if your cat will
(37:32):
acquire or has acquired theinfection. Does that make sense?
Yeah, for sure.
I have feral cats that live inmy backyard. Galveston has a lot
of feral cats. But to the pointwhere we always want to advocate
for especially people in ourarea, too. If you have feral
cats living in your area, youcan call the Humane Society to
help with the trap neuterrelease program where they'll,
(37:53):
they'll take the cats andthey'll neuter them or spay them
to help control the catpopulation. Because certainly as
we see more and more cats, we'repotentially going to see
one over awesomes can canacquire toxoplasmosis. Gotta get
Lucas on the show, buddy?
Well, it would be they would beindirect hosts. Right? Because
they're warm blooded, butthey're not feeling so it would
be an indirect house, they canacquire infection, but they
(38:14):
wouldn't the parasite wouldn'treproduce.
That makes sense throughDanielle, any closing thoughts?
Final thoughts about the paper?
Anything else you want to sayabout it? Yeah, so
I just really thought this wasthe coolest paper ever. And I
hope we get to do more littlejournal clubs. So please,
please, please let us know. Ifyou like this kind of style of
podcasts, we would love to hearfrom you. And if you come across
(38:35):
any papers or topics that youthink are interesting, let us
know in the comments or shoot usa message.
Yep, I agree. I am now much morecognizant of these animal animal
dynamics than I ever was before.
And but it certainly opened upmy mind about the role of
infections and chronicinfections and behavioral or
mental health issues. Andsomething I'll be looking out
for certainly in patient care.
(38:57):
I'm not saying I'm gonna testeverybody for toxo, who is a CEO
or an entrepreneur or risktaker, but it certainly is
something that's gotten methinking about that connection.
Dennis, any closing ideas?
Like I said earlier, I thinkthis is just a very elegant
study. I think it's just showsthe complexity of all of those
life cycles we have in natureand the connection between
(39:20):
different species and parasites.
And yeah, it's just veryinteresting. So do you think
it's still a parasite? Or do youthink it's like, what's the
commensal? Or what's like, ifyou have something that somebody
yawns Yeah,I don't know. I'm gonna leave
that to, you know, the nextscience fiction movie. Chairman.
Yeah, I think it's a parasitefor now. And so, the
(39:42):
parasitologist tell medifferent.
I'm gonna defer to the experts.
Yes, that one Paris, Parisotologist. Please comment in the
in the in the comment section.
Yeah, yeah.
Well, thanks all for tuning in.
This has been a lot of fun. Weall we have some other ideas for
papers we want to talk aboutother topics if there's top If
you'd like to hear about, pleasego ahead and drop us an email,
send us a message. And we arealways interested in hearing
(40:05):
about topics that might be ofinterest to you the listener. So
thanks for tuning in. Thank you.
Bye bye bye.
Don't let the name West Nilevirus tricky. Outbreaks of this
fire has happened all across theUnited States and even in Texas.
According to the CDC, there werealmost 2700 cases in the United
(40:27):
States and 77 cases in Texas in2021. It's transmitted through
mosquitoes, which means whereyour insect repellent during the
summer and fall months, one infive people develop symptoms
such as fevers, rash, andheadaches. But some people can
develop serious symptoms such asconvulsions, vision, loss and
(40:50):
paralysis. Seven Texans diedlast year to the West Nile
virus. There are no vaccines orcures. So prevention is our best
solution. And now, you knowabout the West Nile virus. This
has been a viral minute.
Thanks for listening to theinfectious Science Podcast. Be
sure to hit subscribe and visitinfectious science.org to join
(41:13):
the conversation, access theshow notes and to sign up for
our newsletter and receive ourfree materials.
If you enjoyed this new episodeof infectious science, please
leave us a review on Applepodcasts and Spotify and go
ahead and share this episodewith some of your friends.
Also, don't hesitate to askquestions and tell us what
topics you'd like us to coverfor future episodes. To get in
touch, drop a line in thecomment section or send us a
(41:35):
message on social media.
So we'll see you next time for anew episode. And in the
meantime, stay happy stayhealthy. stay interested
When I think of the greatmajestic predators in North
America, I think about wolvesand cougars. But what if I told
you that those predators aresusceptible to some of the same
parasites that infect the orangetabby currently sleeping on your
laptop and demanding fancy feastor Meow Mix or whatever it is
this week? You guessed it, we'retalking about Toxoplasma gondii.
A the parasite that keepspregnant women from changing
(00:21):
litter boxes. But here's thekicker. A recent study found
evidence that this parasite mayincrease the odds of an infected
wolf becoming pack leader.
Crazy, right? We have a reallyinteresting story coming up
next, so stay tuned.
(00:43):
Welcome to the infectiousScience Podcast.
This is not just another SciencePodcast Nope. Infectious science
is produced by a team from theUniversity of Texas Medical
Branch and the Galvestonnational lab
where we study some of the mostdangerous viruses on the planet.
Our goalis to inspire future scientists
towards a career in science witha focus on one health, one
health one planet. That's right.
(01:04):
One of the approaches publichealth threats by examining the
connections between people,plants, animals and the
environment. We all sharethis show we'll explore how one
health is your health. So sitback and learn something
infectious science whereenthusiasm for science is
contagious. Hello, listener. Hi,everyone. Welcome back to
(01:29):
another episode of infectiousscience podcast here and UTMB,
the galvus National Lab. I'mseated here with my friends and
colleagues, Dr. Daniel Sweetnam,Dr. Dennis benta, and Matt
Dasho. And we're doing somethinga little different today. And we
need to know if it works. So ifyou like what we're doing today,
we want you to tell us in theshow notes, leave a comment, hit
(01:49):
the like button, whatever it is,give us a follow tell a friend.
And we're going to link to thispaper in the show notes. What
we're doing today is we'retalking about a paper,
a little bit of a journal club.
Yeah, journal club.
And we're all going to talkabout this paper. Danielle, you
brought this paper, it was socool to read. I've never read
about this topic before. So itwas really interesting for me to
(02:11):
delve into it. Tell us what thispaper is.
So this paper is a reallyexciting paper and it was
blowing up all over scienceTwitter a few months ago when it
came out. And it was publishedin Nature, which is a really
high impact journal NatureCommunications. And it's about a
parasite that you may have heardof, it's texel plasm, gone di
and this parasite. They'relooking at it in cougars and
(02:33):
wolves and discovering that itmight be altering the behavior
of wolves. And even alteringpack dynamics. Even if the
parasite infects just a singleWolf, it can change that
dynamics of the entire pack. AndI just think that's so exciting
that something so small can havesuch an incredible impact. And
that's kind of to me, just likethe epitome of why microbiology
(02:53):
is so cool.
Yeah, this is super cool. So Idid see this paper on Twitter as
well. But why did you reallylike picot? And and like, what
captured your interest? And whydid you select this paper?
Well, most of what we know aboutToxoplasma gondii. I think most
of it we know about in preypredator dynamics, and we'll
(03:15):
talk about that a little bitlater. And Yellowstone National
Park is this really interestingarea. And that's where the study
is being done, where wolves andcougars, their territory is kind
of overlapping. And so we havethis really exciting multi
predator multi carnivores systemthat we don't normally see that
wolves and cougars are usually,even though they have the same
(03:36):
prey are usually kind ofselecting to be separate. So
this really interesting area isallowing for this interesting
spillover of a pathogen, which Ijust think is just this really
interesting area and I will kindof want to go to Yellowstone
National Park. So it's a niceplace to think about.
Yeah, I've never been either. Solistener if you're interested in
(03:56):
sponsoring a an infectiousscience trip out to Yellowstone,
we know take Venmo Cash App,Zell. So Dennis, you're the vet
tell us about toxic so I onlyknow about it and humans, right,
we learn about and I've takencare of folks who've been
infected with toxo mostlyimmunocompromised people, people
(04:17):
with HIV AIDS usually advanced,the HIV they're
immunosuppressed. They have lowimmune systems, they can't fight
off viruses and bacteria likesomeone who's got all of their
white cells and then we alsohear about it in pregnancy. You
know, those don't clean the catbox, you know if you're
pregnant, because you mayaerosolized the feces and
inhaled it or be exposed to it.
What is this pathogen and whatdoes it look like in animals?
(04:40):
You know, in vet school, you'veToxoplasma gondii is obviously a
staple that you have to learnabout, but not so much because
it causes you know, devastatingdisease and animals but
obviously, because it's azoonotic disease and can be
transmitted to humans, but we dolearn about it. Obviously, cats
being the main host and know alot of Veterinary Medicine.
focuses on domestic animals oncats and dogs. But it's not just
(05:03):
house cats, right? No, that'sThat's correct. Toxoplasmosis is
a disease cause you know, as wetalked Toxoplasma gondii i and
it theoretically can infect anyor many warm blooded animals,
including pets, livestock birds,and obviously people so I think
the reason why we focus on catso much domestic cats is because
(05:25):
they live in close closeproximity to us and a big one
health question humans and petsand close proximity and, and
human infection can occurthrough domestic cats. And I
think that's why this is part ofthe education and why we learn
about this so much. And, youknow, typically most infected
adult cats, they appear healthy.
However, some cats may developpneumonia, liver damage or some
(05:46):
other health problems, but inmost of the time, it's really
avert, there's no signs ofillness in cats, maybe if they
are infected, they arelethargic, loss of appetite, but
it's not really just a big dealin vets medicine.
So some people are some peoplefrom cats being people, cat
(06:07):
owners. So some cats, that meando they manage? Some of them
don't have any symptoms at allright? I mean, they
can most of them. Yeah, most ofthem. And if you have an
immunocompromised cat or akitten, for example, feline HIV,
right F IV that canimmunosuppressed, the cat, then
the parasitic infection has nocontrol or is not controlled,
(06:28):
and then we'll just go rampid inthe cat and then the cat will
get sick.
Okay, so I'm hearing why it'simportant for cats certainly
know why it's important forhumans. So Daniel, when you were
reading this stuff, whatprompted these guys to do this
study, what was the main problemthey were trying to understand.
Solet's back up a minute, because
there's a couple of things Ireally want to emphasize. Okay,
emphasize emphasize this, thisis a protozoan, just a single
(06:50):
cellular parasite. And likeDennis said, It infects warm
blooded animals in general, thereal big important key here is
it needs some type of feline toreplicate. This is really,
really critical part of itslifecycle, the direct host is
some kind of Feline, everythingelse is like an intermediate
host. And when it spread from ananimal that's not a cat, it
(07:14):
escapes the intestinal lining,and it can form me cysts, and
muscle and brain tissue. Andthere's a lot of evidence that
it could affect behavior. Now,the way it's spread is by
basically three ways you can bespread by consuming the parasite
eggs, but that can only comefrom one of the cats, and it can
be through eating the cat, or itcan be through coming in contact
(07:38):
with feces of the cat or thescat or something that's been
contaminated with it. The otherway you can contract it is if
you eat infected meat, anythingthat's been infected with the
parasite. So it can be aninfected cat or an infected dog
or cow or anything like that.
But the really important thingthat you have to remember for
(07:59):
the rest of the story is it'sonly replicating in cats, or
cougars and our story. And soyou use a couple terms there. I
just want to like clarify. Soyou said direct host and an
intermediate host right? So canyou kind of flesh those out a
little bit? Because I in myhead, I was actually reversing
them. I was like, Oh, theintermediate host must be the
one where it's replicating. Andthen the direct one is where
it's reversed,right? Yeah. So the direct host
(08:21):
is where it's replicating. Andthat's cats. Everything else is
an intermediate host, you canget it from eating the
intermediate host. But you'renot going to get it from coming
into contact with the feces ofthe host.
So are you saying in theintermediate host says no
replication in the none at all,no. amplification of the
(08:44):
parasite in the intestine?
No, it just kind of travels fromthe intestine to kind of muscle
or brain tissue and formsassists to protect itself and it
goes chronic, it kind of justhangs out and doesn't do
anything unless you'reimmunocompromised. And then it
can start to cause some kind ofinflammation in some disease,
but it will just hang outforever indefinitely, but not
(09:04):
replicate.
And I'm against scare tactics.
I'm against just anybody knowsme. I don't like people would be
scared. But the numbers thatwe're seeing were pretty crazy.
Like 2 billion people in theworld. Probably infected. Yeah.
Okay. That's a lot a lot. Right.
Idon't know the exact number. But
it's a very high prevalence inthe population, which is
something we don't always thinkabout. Right?
(09:25):
Yeah, well, probably becauseit's not causing any disease in
most of those people. And inmost of those animals that's not
causing any disease. Yeah, Ithink this is something that the
major take home messages I wouldsay is that a lot of people get
exposed to toxoplasma and theywill deal with the infection,
but they will just seclude theparasite and there's no clinical
signs as no threat to help inany way. So that's the most
(09:48):
common outcome of an infectionor an exposure with toxoplasma.
I think that's kind of likereally something we need to
emphasize.
Yeah. Okay. So that's kind ofThe basics of the parasite. But
what's really, really cool isthis kind of idea that this
little micro unicellularorganism is there's a lot of
(10:10):
evidence that it can changebehavior, even in these hosts
where it's not doing anythingelse, and it's just hanging out.
So, for example, in rodents, andmonkeys, and hyenas, it all
really makes them more prone todo risky things. In rodents, it
makes rodents less adverse tohouse cat urine, and in monkeys
that makes them less averse toleopard urine. And in hyenas
(10:31):
specifically, it makes them alot more bold around lions,
right? These are all reallydangerous things, this increases
the likelihood that theseanimals that are infected are
going to be around a wild catthat can eat them, and then that
cat would become infected. Sothis parasite makes the animals
bolder, these prey animalsBoulder, puts them at risk, and
(10:54):
put some around these catpredators and then kind of
perpetuates itself. And thatkind of interesting kind of
subversive stylealmost sounds a little bit like
rabies, right? Like where youhave herbivores that all of a
sudden become more docile whenthey infect an easier prey for
predators. Correct. Do you wouldyou agree? Yeah, for sure.
Yeah, it was so interesting,Danielle, because you sent me
(11:14):
down a rabbit hole when you sentthis paper because I started
thinking, oh, man, like, I onlyknow the clinical part right
out, I know, the dose ofantibiotic you're supposed to
give I know when you're supposedto, you know, the guidelines for
HIV say you're supposed toscreen for talkshoe. And when
you're supposed to treat and soI know those things, but I
didn't know anything else aboutwhat toxic do to behavior. And
(11:36):
as I started traveling down therabbit hole, into the
literature, I found severalpapers, right in humans
describing that actuallytoxoplasma infection is
associated with things likeschizophrenia, there was a paper
that described that people whoconsume alcohol were more likely
(11:57):
to have behavioral effects, ifthey were toxic positive, found
one paper that was done onuniversity campuses, it was kind
of a funky study design, butthey looked at college students
and found that people who werebusiness majors were 1.4 times
more likely to be toxo IgG.
Positive. So.
So compared to what biologymajors, right.
(12:20):
So I don't know what that saysabout all of us. I was a music
major. Sonow I think all these papers are
really interesting. And I thinkthis has been a theme for a long
time, what toxoplasma can do tobehavioral changes. And it's not
a new theme, right? I mean, thiswe know this from the animal
kingdom, how parasites canmodify, and behavior and so on.
I'm still skeptical, though,what is the likelihood of 1.4
(12:43):
times really mean?
Right, the paper I saw is thatit looks like people that have a
chronic infection with toxo haveincreased testosterone and
dopamine. So there's an ideathat maybe with the increase of
those two hormones that thatmight lead to risky behavior.
But what does risky behaviorlook like? There's a lot of
(13:03):
types of risky behavior. So itmight be something that's just
if there's a behavioral changegoing on in the human
population, it might be reallyhard to quantify, because risky
is super subjective, right. Andit's easy. When we talk about
the paper they define for riskybehaviors that they're going to
lookat. Yeah, but I think also more
like the biostatistics like 1.4%times more likely, is this very
(13:26):
high, orit's just hard to do prospective
studies. We can't like infectpeople intentionally.
In fact, freshmen, and then seewhat major
letters from iOS x community,yeah, on this, we're not
suggesting this, please don't dothat. But it was interesting to
me to see that there were theseat least correlative studies in
(13:49):
the human literature saying,well, actually suicidal
behavior, schizophrenia, whichis heavily dependent on
dopamine. So these were alteredby the presence of this
parasite, or at least haveantibodies to this parasite. And
so very, very, very interestingthat it could potentially have
somenose to humans. Maybe in a few
years, when we talk about mentalhealth, we'll be looking at
(14:11):
infectious diseases a little bitmore closely and associated with
that, but yeah,I know a lot of infectious
disease doctors that would bevery pleased to know they
they've their their field is somuch so relevant in so many
ways. Yeah. Infectious diseaseand cancer, infectious disease
and hypertension, infectiousdiseases and heart disease, you
know, infectious disease andmental health. We know from
COVID-19 that people who aredealing with post acute COVID
(14:34):
syndrome or long COVID aredealing with a lot of mental
health side effects. Right.
So what happened in the paper?
Let's talk about the papersorry, tangent go over. Okay.
So we talked about all theseother studies where toxin has
been studied, and I mentionedbefore, most of the studies, at
least in the animal kingdom,were looking at predator prey
(14:57):
dynamics, but that leaves a lotof other kind of directions up
for questions. And in theYellowstone National Park wolves
were driven out of that area inthe early 1900s. And then were
reintroduced in 1995, likebetween 1995 and 1997. And since
that time, there has been a tonof effort to monitor their
(15:18):
health and behavior andsomething really similar
happened with cougars, althoughthe the Cougars reintroduce
themselves, but still, there'sbeen a lot of monitoring
Cougars are gonna go wherethey're gonna go. In this case,
don't try to tell a cougar. Heor she can go I
don't know why that's funny. Ifeel like something about it is
funny. Okay, so yeah, theseanimals that were excluded from
(15:40):
this area and reintroducedWilson Cougars both prey on
smaller animals, but they'rerarely found in the same
location, except for here atYellowstone National Park
specifically in the north. Mostof the Cougars kind of colonized
the the northern part of thepark where there's lower
elevation. But in the winter,the bison and elk and mule deer
(16:01):
migrate down elevation into thisnorthern part of the park. And
when the prey animals migrate,well, the wolves follow. So for
this period of time in thewinter, there's this really
solid overlap between the two.
And the Cougars just so happenedto be carriers of toxo,
specifically, and it's actuallyincreasing quite a bit between
1989 and 2004. About 45% of theCougars in that area that were
(16:23):
surveyed were toxic, positive.
And more recently, a survey thatwas done in 2016 to 2020, that
number increased to 73% of theCougars in this area are toxic
positive. So boom, here's thisreally great opportunity, the
samples that have beencollected. There's data about
behavior, there's data, there'ssamples, serology samples that
(16:45):
have been collected, this is agreat area to really leverage 26
years worth of data and samplesthat were collected to look at
this interaction.
So Daniel, when you say a toxicpositive, so in technically
term, in technical terms, theyare seropositive, they have
antibodies against Yeah,Toxoplasma gondii. I do you
(17:06):
know, is the the sero positivityautomatically a sign that the
infection has taken a footholdin the person or the animal?
Well, I think it's assumed thatevidence of prior infection
indicates current infection,because I think what's known
about toxo in general is wedon't clear the infection, the
(17:27):
virus creates cysts in the brainand the muscle tissue and
persists for the lifetime of theanimal. I haven't read anything
about if there are any animalsthat are able to clear the
infection. So I think if you'veever been infected, it's
assumed, at least in this study,and other studies I've looked at
the infection is still there.
Right? So that makes sense. Butcan we infer that only because
(17:50):
it's positive that there's somebehavioral change automatically?
No. But that's what they lookat. So they had two goals.
First, they want to determinebecause not all the wolves in
the park were living overlappingwith cougars. So they were
saying what kind of factorscontribute to infection and
wolves. And the second thingthey're trying to look for is
does infection alter wolfbehavior? So there were two
goals?
(18:10):
That was really, really cool.
And so gosh, I can't imagine howthey did that. Did you get a
sense of like how they fancymath behavior? Yeah, it's really
was a lot of math. Yeah. A lotof math in there.
Yeah. So for the first kind ofquestion to determine the
factors that affected thelikelihood that the wolves would
become infected with toxo. Youcan't just say, were they living
(18:32):
in the same area, right, becausethere's a lot of other things
that can contribute. So age ofthe wolf sex of the wolf,
whether or not the wolf was apack leader or not the coat
color of the wolf, things likethat. And then what poor portion
of their territory wasoverlapping with the Cougars. So
men kind of accounted for thatusing a variety of like
statistical tools andmathematical modeling. And what
(18:54):
they found for that question wasthat the only feature they found
that was significant was whetheror not the wolves shared
territory with the Cougars. Andthe the wolves that had a lot of
their territory like highoverlap with the Cougars were
nine times higher odds of beinginfected with toxo.
So we this basically showedthese these environmental
(19:16):
changes happen, the wolvesmigrate down to share kind of
the same habitat as the Cougarsdo. And because of this overlap,
we definitely see an increase intransmission from the direct
host to this intermediate hostwhere the thing kind of find its
end pathway.
Talking about transmission. Youknow, I think all of the
(19:37):
listeners who own dogs know howdogs sometimes even pick up cat
poo, right? I think we've we'veall seen this. One fun fact that
I found doing my research onthis is that the the O says from
Toxoplasma gondii I theyactually need to spend 24 hours,
maybe even up to five daysdepending on environment. mental
(20:00):
conditions in the environmentbefore they can become
infectious. So it's not that youfind feline stool or something
like that, and then it'simmediately infectious. So it
takes some time for the the oldcysts to mature for lack of a
better term to becomeinfectious. So I know this is
not really covered in thisarticle, but
(20:20):
so it can't be the fresh stuff.
Fresh juicy stuff. It's gotta bethe rock hard, you know, been
out there for a little while.
Those are that's the realis so to say so full anything
about seasonality in this paper?
And do you think theyspeculate they say that they
don't think it is infected prey?
So they don't think it's theinfected elk or deer? And they
(20:42):
did some surveillance? And Ithink elk it was and they didn't
really find any seropositive.
Elk are a very small portion ofseropositive elk. So they
suspect that it's direct contactwith the Cougars, or the Oh
sites in the scat, I guess. Butin the winter, I don't know
maybe there's like a freeze thawthing going on, or could even be
contaminated water, orcontaminated vegetation or
(21:03):
something. Or I mean, they couldeven be eating a burger. I don't
really understand thosedynamics, like do wolves. Would
a pack of wolves prey on acougar? Or would that be the
other way round? It'll getemboldened. Yeah. Maybe because
if a wolf were to eat a cougar,or they came across a dead
cougar or something, and Dennisthe wolves do that,
(21:26):
you know? Sure. Yeah. I'm justamazed by the seropositivity
level of what was it? 45% orsomething like that. So there
must be ongoing transmissionwithin the Cougars? Well, yeah.
And also to spill over to thedogs. Dogs to the wolves. So
sorry. Well,so what else did they find? So
that was their first study?
That was their first question.
age, sex, social status and coatcolor did not affect
(21:48):
transmission of toxic to wolves,but overlapping territory did.
The second question was the bigone that kind of cool one did
toxic infection alter wolfbehavior? So here were they
identified four risky behaviors.
The first one was becoming PACleader. They consider that a
(22:10):
risky behavior because there'ssome kind of violence involved
in that, as I understand it'squite a violent transition like
a fight. Is it like a fight tothe death? Or is it or somebody
retreat or somebody? Yeah. Soyou would expect that to be
that's obviously a riskybehavior.
I mean, going into any kind ofleadership politics, this is
risky behavior. You know, you'reputting a lot of the comfort of
(22:31):
your home anonymity. You know,these wolves are just putting
themselves out there.
Yeah, maybe that should be astudy. Yeah. Parasites among
political leaders? Oh, gosh,don't get us started on that.
There's so many jokes there.
There's like you can take itdown.
Yeah, okay, let's remainfocused, bringing in the second
(22:52):
risky behavior was dispersal. Sobasically, this is when a wolf
leaves his pack or her pack andnever comes back. And usually
this is, this is really risky,right, because you lose the
protection of the pack,particularly in the harsh
environment of winter. Butgenerally wolves do this, and it
increases the likelihood thatthey'll find a mate. Or maybe
they can come across anotherpack and try to challenge that
(23:13):
pack for leadership. Sodispersal is another high risk
behavior in wolves. And then theother two were related to
people. One was habituation,which is how likely the wolf is
to approach people or a vehicle.
And then the the final riskybehavior was Did they die as the
result of interaction with ahuman. So those were the four
risky behaviors that theyassessed. So first off, they
found that of the wolves thatdispersed, they were 11 times
(23:39):
more likely to be infected withtoxo. So that's a pretty big
increase, and your willingnessto disperse. That's pretty
incredible. And this is kind ofreally the thing that stuck out
the odds of an infected wolfbecoming a pack leader was 46
times higher in a seropositiveinfected wolf than an uninfected
(24:00):
Wolf. So that's almost 50%Higher. So that's huge. And just
imagine you've become leader ofthe pack. And now you're the one
taking risky behavior, andyou're maybe engaging your whole
path in this new risky behavior.
And just think of theimplications for like social
learning and new kind of wolfcubs that are being born into
that pack. That's a riskierpack. But the two things about
(24:23):
humans are the two risky thingsabout humans, they didn't find
any statistically significantdata. So that is good. And it's
not increasing the likelihoodthat the wolves are going to be
approaching people or somethinglike that, because
that's quite risky for them,right? Like that's, yeah, people
are probably scared of that.
We're scared of wolves, but it'sprobably the biggest risk to
them.
Right? The thing is, is theyeven acknowledge it that their
(24:44):
sample size for that was very,very small. They didn't really
detect much interaction betweenwolves and people. So wolves
that are infected might be morelikely to approach people but
I'm really justa thought here on the side. Not
crucial, but I think that's whenit comes to rabies education.
And we always teach people thatif you find a carnivore or
omnivore that's very docile thatthis could be a sign of, you
(25:06):
know, some form of infection orrabies infection. Right. So a
wolf approaching being way morecomfortable with the human could
trigger somebody you think, youknow, we need to shoot the wolf
because it's you know, hasrabies.
Interesting. Yeah. No, that's,that's fascinating. Danielle, as
I was reading that I was just,again, harkening back to that
(25:29):
human side thing, we'redefinitely see differences in
behavior that's caused by thisparticular parasite. So very
cool. Yeah, it's so cool. It'sso fascinating.
What do you think are theimplications for this? They've
done this really elegant study,they've really, I think, shown
something. And certainly thathas been shown experimentally in
(25:52):
controlled conditions, in rats,and as you mentioned, in some
other animals, that there arethese behavior changes that
happen with Toxoplasma gondii,infection. And now they've shown
in a real world environment, andwith control of a lot of
variables and a lot of data,that this is independent of
other things. This is acontributor to not only changes
(26:16):
in the individual's behavior,the individual wolves, but the
pack behavior, like you pointedout. So where do you think this
leads us? What are theimplications for this? Where
does it go for maybe otherdiseases? I always think, you
know, one, health is not alwaysabout human health, right? It's
about interconnections humananimal environmental health. And
so we selfishly sometimes lookat animal studies as like, some
(26:37):
excuse to apply it to humanpopulations, right? Do you think
we're there yet to be able toextrapolate that? Or is it just
another line of investigation?
So I don't know, maybe it'd bebetter to ask you those
questions as a physician,because for me, what I'm
thinking about is how does thisaffect park management? How does
this affect wildlife management,the overlap in these two
(27:00):
predators is kind of somethingthat isn't really seen anywhere
else. And it's seen in this areawhere the wolves were
artificially reintroduced intothat, and something that we
looked more closely at and maybeshould look more closely at
moving forward. And the impactthat this could ultimately have
on the wolf population, right?
This is all happening during thewinter. And this is also just so
happens to be when wolf matingseason and whopping season is
(27:22):
going on, this is increasing thelikelihood that a wolf will
become infected while they arepregnant and carrying cubs. And
this is going to increase thelikelihood that it's transmitted
vertically from mother tooffspring. And if just like
within humans, there can bereally extreme damage to the
fetal Wolf, if the mother isinfected. So will this have a
(27:46):
long term decrease in the wolfpopulation overall? Will it
increase the likelihood that thewolves will die? Because they're
taking a risky behavior? Doesthis kind of interaction with
Cougars put them at risk inother ways than just kind of the
predator predator carnivore,carnivore interactions? So yeah,
that's really what I'minterested in, and what I'm
going to be looking for in thefuture.
(28:08):
Well, if the authors arelistening, please continue to
collect data for the next 26years.
And what an amazing example ofwhy it's so important to collect
data for long periods of time,right? The study has 26 years
worth of data. Oh, my gosh, it'sincredible. How, how old were we
26 years ago? You know,obviously, the people that did
this work, were not the peoplewho started it. So what kind of
(28:30):
foresight went into this?
Absolutely. I think this is avery elegant study. I think it's
just amazing paper. I feel likeI'm the Debbie downer here, the
critical voice. But one thingthat I just have a really hard
time wrapping my head around ishow does assist really leads to
(28:50):
behavioral changes. I mean, youtalked about different levels of
dopamine, different levels oftestosterone. And I think that
makes a lot of sense. But fromwhat I remember from
histopathology, back in the day,those parasites those cysts,
they randomly occur in thebrain, and not in specific
(29:10):
regions of the brain. What youwould expect if you think about
the hypothalamic, pituitarygonadal axis, or whatever it's
called, right? So where you haveto have a lesion in the
hypothalamus, and that willmaybe change the expression of
GN HR or something like that,right. And last, but you know,
(29:31):
like the axis that triggerstestosterone production, so I
just don't understand how arandomly placed cyst will lead
to an increase in testosterone.
And that's, I think, forendocrinologist answer and
there's probably a couple ofexperimental papers that
describe that. We do know that alot of infections either by way
(29:54):
of a direct effect of thepathogen the infection happens.
Thing sets up shop, it can causethe secretion it can induce by
secreting its own chemicals thatcan cause the secretion of
certain hormones, orneurotransmitters like dopamine,
but also possibly theinflammatory response. Right? So
maybe it's a question of how ourbodies are responding to the
(30:17):
pathogen. So it's thatconnection. And I can't speak
intelligently about either ofthose two things. But I would
say those are interestingquestions that for me would come
from this.
Absolutely. And I think that wealways have these discussions in
the one health realm that's whenit comes to one health, we talk
about policy and have theseframeworks and but I think
what's often missing missing isone health research. And I think
(30:41):
this is such a good example ofOne Health Research, where you
have the behavioral changes. Andnow let's dive into the
molecular side of things. Let'snow understand the pathogenesis
behind this. And I think thatis, by definition, one health
research, and I think thereneeds to be more effort on this.
I think that would be maybe thenext paper we can read, we'll go
(31:03):
look and see if any of ourlisteners know of any papers
that talk more mechanisticallyabout how parasites or viruses
can alter expression of hormonesor neurotransmitters. Yeah, I'm
sure there's people I'm surethis is an area of research, not
my area ofenvironmental peace. You know, I
used to live in Botswana,Southern Africa. And there's
(31:24):
this lovely Game Reserve, rightacross the border from Botswana
into South Africa. That's calledthe Monday QA game game reserve,
and shout out to Tao lodge wherewe usually stay and bow in the
local language means means lion.
So this particular region of thepark that we stay in is full of
lions, and in fact, becomingquite a big problem in the park,
(31:47):
because not only are they veryterritorial and battling each
other, but they also compete forfood sources. And over the
years, South Africa, instituteda lot of safety policies for
wild animals. And so they'vealso become a destination for
rescue lions. And so as the lionpopulation has, in some ways,
(32:08):
naturally, and in some waysartificially increased in this
enclosed game park, but it'sstill a game park, I wonder
about, you know, these arefeline animals, right? So how
much toxo is out there? And whatare we gonna be seeing maybe
very bold giraffes, oh, that arejust coming up to two lions,
two lions and saying, Hey,Scott, maybe
(32:31):
they're herbivores, but youknow, that can cover the plant
life. And so I, you know, youreally do wonder about not only
natural increases in thesepopulations that can be
replicated hosts for thesepathogens, but also the dynamics
of when humans introduce them.
So human behavior, once again,it's not always terrible. We're
doing something good, right?
(32:51):
We're trying to save lions,right. But there's always
potentially downstreamconsequences to be considered.
So Matt, for our listeners thatdon't know too much about
toxoplasma. What can you tell usabout congenital toxoplasma
infection and pregnant women andcleaning the litter box and so
on? Do you have some advice? Andcan you tell the listeners a
(33:12):
little bit about that?
So I can't say muchintelligently because I'm not an
OBGYN. Boy, the last time I tookcare of a pregnant person was a
long time ago. But generally,what we know is that it causes
congenital fetal malformations.
It's one of the torch infectionsthat is associated with fetal
abnormality, whatis what is torched mean?
(33:33):
So thanks for asking thatDennis. Torch infections are
toxoplasma others which includessyphilis, and hepatitis B,
rubella, cytomegalovirus, CMV,and herpes simplex. So that's a
group of infections that we'realways keen to prevent, in
practice, how do the babiesbecome its vertical, so these
pathogens are able to traversethe placenta. So as you're just
(33:57):
stating, as your fetus isgrowing inside the uterus,
there's this really beautifulapparatus, that's the placenta
that it's not much to look atwhen it's on the outside on the
inside. It is just a gloriousnetwork of blood vessels and
signaling and it's basically themain organ that filters maternal
blood for any kind of adversethings and make sure that
(34:19):
whatever is coming to the fetusis going to be nutritious, and
there are certain pathogens thatevade that placental barrier.
So Danielle, what would you sayif a pregnant woman wants to
surrender her cat because she'safraid that she could get
toxoplasmahave your husband take care of
the cat. So the primary risk topregnant women would be in
(34:39):
dealing with the cat excrementand cat feces, so cleaning the
litter box or if you have anoutdoor cat and you're gardening
or something like that, or ifyou're living around a lot of
stray cats so there's certainways that you can protect
yourself from that kind oftransmission. You can wear
gloves while you're changing thelitter box, you can ask someone
else in your family To changethe litter box, you can have
(35:00):
your cat, go stay with a friendduring the time that you're
pregnant and then come back andlive with you. So there's
definitely ways that you cankeep your cat in your life after
you're pregnant, and be safe andconfident that you're not going
to get tuck. Soyeah, and it's not like a
guarantee, right? It's a risk.
(35:20):
It's like anything your catmight not have toxo. And so I
think, you know, you don't wantto cause this widespread panic
that you know, every time youget near a litter box, you're
gonna be at the risk of gettingtoxo I think it's just important
to know, these are risks that ifyou have the ability to have
someone else, change the litterbox, great. If not wear barrier
protection, wear masks, just besafe about it. We tell pregnant
(35:41):
women not to eat unpasteurizedraw cheese, right for risk of
listeria infection. We will talkabout safe sex, we talked about
a lot of things to try toprevent potential diseases that
could harm the fetus. So I thinkit's just one of many, but it
doesn't mean that get rid of thecat is probably overkill.
And you can still go visitYellowstone National Park if
you're pregnant.
(36:02):
Absolutely. Just stay maybe, youknow, just go away from the
calcified feces of the Cougars.
Right? Those are those are not,those are the next.
One thing I also wanted to pointout when it comes to the
potential risk of pregnant womenacquiring the infection from
cats. Cats don't shed toxoplasmaconsistently, they will only
(36:26):
shed the old cysts or the eggsin their feces for approximately
10 days after the initialexposure. Oh, interesting. So
it's not that a cat you own acat in its lifetime, it will
just shed Oh, is this or eggs,toxoplasmosis. It's just up to
10 days after the initialexposure. So the question is,
(36:46):
you probably don't know if yourcat has been exposed and when
and will be exposed. But that'sdefinitely not the concept of
lifelong shedding.
Interesting, interesting.
And if what you said before istrue, Dennis, which is that it
takes some time in theenvironment for toxo to develop
the ability to infect a newhost, then I mean, as long as
(37:09):
you're cleaning up fresh stuff,then changing the litter pretty
frequently. Shouldn't that bepretty good? That'd be a pretty
good practice, I would say. Soit's just can't be old rock hard
stuff, right?
Yeah. And if you have an indoorcats, and you know that the cat
is not going outside eatingrodents that are infected, or
something like that you at leasthave a grasp on if your cat will
(37:32):
acquire or has acquired theinfection. Does that make sense?
Yeah, for sure.
I have feral cats that live inmy backyard. Galveston has a lot
of feral cats. But to the pointwhere we always want to advocate
for especially people in ourarea, too. If you have feral
cats living in your area, youcan call the Humane Society to
help with the trap neuterrelease program where they'll,
(37:53):
they'll take the cats andthey'll neuter them or spay them
to help control the catpopulation. Because certainly as
we see more and more cats, we'repotentially going to see
one over awesomes can canacquire toxoplasmosis. Gotta get
Lucas on the show, buddy?
Well, it would be they would beindirect hosts. Right? Because
they're warm blooded, butthey're not feeling so it would
be an indirect house, they canacquire infection, but they
(38:14):
wouldn't the parasite wouldn'treproduce.
That makes sense throughDanielle, any closing thoughts?
Final thoughts about the paper?
Anything else you want to sayabout it? Yeah, so
I just really thought this wasthe coolest paper ever. And I
hope we get to do more littlejournal clubs. So please,
please, please let us know. Ifyou like this kind of style of
podcasts, we would love to hearfrom you. And if you come across
(38:35):
any papers or topics that youthink are interesting, let us
know in the comments or shoot usa message.
Yep, I agree. I am now much morecognizant of these animal animal
dynamics than I ever was before.
And but it certainly opened upmy mind about the role of
infections and chronicinfections and behavioral or
mental health issues. Andsomething I'll be looking out
for certainly in patient care.
(38:57):
I'm not saying I'm gonna testeverybody for toxo, who is a CEO
or an entrepreneur or risktaker, but it certainly is
something that's gotten methinking about that connection.
Dennis, any closing ideas?
Like I said earlier, I thinkthis is just a very elegant
study. I think it's just showsthe complexity of all of those
life cycles we have in natureand the connection between
(39:20):
different species and parasites.
And yeah, it's just veryinteresting. So do you think
it's still a parasite? Or do youthink it's like, what's the
commensal? Or what's like, ifyou have something that somebody
yawns Yeah,I don't know. I'm gonna leave
that to, you know, the nextscience fiction movie. Chairman.
Yeah, I think it's a parasitefor now. And so, the
(39:42):
parasitologist tell medifferent.
I'm gonna defer to the experts.
Yes, that one Paris, Parisotologist. Please comment in the
in the in the comment section.
Yeah, yeah.
Well, thanks all for tuning in.
This has been a lot of fun. Weall we have some other ideas for
papers we want to talk aboutother topics if there's top If
you'd like to hear about, pleasego ahead and drop us an email,
send us a message. And we arealways interested in hearing
(40:05):
about topics that might be ofinterest to you the listener. So
thanks for tuning in. Thank you.
Bye bye bye.
Don't let the name West Nilevirus tricky. Outbreaks of this
fire has happened all across theUnited States and even in Texas.
According to the CDC, there werealmost 2700 cases in the United
(40:27):
States and 77 cases in Texas in2021. It's transmitted through
mosquitoes, which means whereyour insect repellent during the
summer and fall months, one infive people develop symptoms
such as fevers, rash, andheadaches. But some people can
develop serious symptoms such asconvulsions, vision, loss and
(40:50):
paralysis. Seven Texans diedlast year to the West Nile
virus. There are no vaccines orcures. So prevention is our best
solution. And now, you knowabout the West Nile virus. This
has been a viral minute.
Thanks for listening to theinfectious Science Podcast. Be
sure to hit subscribe and visitinfectious science.org to join
(41:13):
the conversation, access theshow notes and to sign up for
our newsletter and receive ourfree materials.
If you enjoyed this new episodeof infectious science, please
leave us a review on Applepodcasts and Spotify and go
ahead and share this episodewith some of your friends.
Also, don't hesitate to askquestions and tell us what
topics you'd like us to coverfor future episodes. To get in
touch, drop a line in thecomment section or send us a
(41:35):
message on social media.
So we'll see you next time for anew episode. And in the
meantime, stay happy stayhealthy. stay interested
Popular Podcasts
24/7 News: The Latest
The latest news in 4 minutes updated every hour, every day.
Therapy Gecko
An unlicensed lizard psychologist travels the universe talking to strangers about absolutely nothing. TO CALL THE GECKO: follow me on https://www.twitch.tv/lyleforever to get a notification for when I am taking calls. I am usually live Mondays, Wednesdays, and Fridays but lately a lot of other times too. I am a gecko.
The Joe Rogan Experience
The official podcast of comedian Joe Rogan.