June 6, 2025 • 43 mins
A hidden killer lurks in the humble dust of forgotten cabins and outbuildings across America. World-renowned virologist Dr. Thomas Ksiazek takes us behind the scenes of the landmark 1993 Four Corners outbreak, where hantavirus first emerged on the national stage, claiming lives with a swift and devastating pulmonary syndrome unlike anything seen before in North America.
With over four decades on the frontlines of viral discovery and outbreak response, Dr. Ksiazek shares the detective story of how his team at the CDC identified Sin Nombre ("no name") virus by drawing on their unique expertise with Asian hantaviruses. He explains the ecological cascade that triggers cyclical rodent population explosions, creating perfect conditions for spillover into human communities.
The conversation turns chillingly relevant as we discuss recent high-profile cases, including the tragic February 2024 death of Betsy Arakawa Hackman, and a cluster of deaths in Mammoth Lakes, California. Dr. Ksiazek explains why spring cleaning poses a particular risk when disturbing rodent-contaminated areas, and why conventional treatments often prove ineffective against the rapid progression of hantavirus pulmonary syndrome.
As both a co-discoverer of the original SARS coronavirus and a veteran of countless global outbreaks, Dr. Ksiazek offers profound wisdom on what makes outbreak responses succeed or fail. His insights on the critical importance of early detection and international cooperation carry urgent lessons for our pandemic-weary world. Whether you're a scientist, healthcare worker, or simply someone who might one day clean out a dusty cabin, this episode delivers potentially life-saving knowledge about a persistent threat hiding in plain sight.
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.
Speaker 2 (00:09):
This is a podcast about One Health the idea that
the health of humans, animals,plants and the environment that
we all share are intrinsicallylinked.
Speaker 3 (00:17):
Coming to you from the University of Texas Medical
Branch and the GalvestonNational Laboratory.
Speaker 2 (00:21):
This is Infectious Science.
Where enthusiasm for science?
Speaker 3 (00:25):
is contagious.
Speaker 4 (00:30):
Welcome back to the Infectious Science podcast.
I'm here today with Dr CamilleLedoux.
How's it going, camille?
When are you moving Next week?
Oh, okay, are you excited?
Yes, I'm very excited.
Nice, has it sunk in yet to be?
Speaker 5 (00:44):
a doctor.
It's weird.
Yeah, it's getting there.
I feel like it's not old, ithasn't gotten old?
Speaker 4 (00:49):
All right, we're missing Christina today.
Yes, we are, but we'recompensating with a special
guest, alex Alvarado.
Alex, how are you?
I'm doing all right, how areyou?
Speaker 1 (01:01):
Yes, so I'm a second year microbiology and immunology
graduate student in the lab ofTom Geisbert and my project is
currently working on developinga recombinant vesicular
stomatitis virus vectoredvaccine for guanarito virus
which causes Venezuelanhemorrhagic fever.
Speaker 4 (01:16):
Okay, so hopefully we'll see or hear more of you on
the podcast.
I certainly hope so.
All right, welcome.
And then we have a very specialguest today and I'm super
excited.
I wanted to record this episodefor probably two years now.
Today's guest is a true giant inthe field of infectious disease
research and global outbreakresponse.
(01:38):
Dr Thomas Kysak is aworld-renowned virologist,
veterinarian and epidemiologistcurrently serving as the
director of high containmentlaboratory operations here at
the Galveston National Lab atthe University of Medical Branch
, where we are here in ourpodcast closet.
Over a remarkable careerspanning more than four decades,
dr Kaysik has been on the frontlines of some of the world's
(02:01):
most significant viral outbreaks, including Ebola, marburg,
nipah, rift Valley Fever, sarsand the topic of today's session
, hantaviruses.
He's been credited to be one ofthe co-discoverers of SARS
coronavirus in 2003 during theoutbreak back then, and Dr
(02:21):
Kaysack's expertise is rooted ina unique blend of veterinary
medicine, military service andlaboratory science.
After earning his DVM fromKansas State University, he
embarked on a distinguished21-year military career with the
US Air Force and Army, workingin research stations around the
world, ultimately retiring as alieutenant colonel.
(02:42):
Ultimately retiring as alieutenant colonel.
Following his retirement fromthe military.
He joined the Centers forDisease Control and Prevention,
where he was part of theleadership team of the Special
Pathogens Branch and coordinatedinternational responses to
emerging viral threats.
And here's the kicker With over300 science publications to his
name and more than 45,000citations, that's incredible.
(03:04):
That's incredible.
Speaker 5 (03:05):
That's wild.
Speaker 4 (03:07):
Dr Kaysack's work has shaped our understanding of
hemorrhagic fever andarthropod-borne viral diseases,
and his rapid diagnosticinnovations have saved countless
lives.
He's obviously the recipient ofmultiple honors, including
three Secretary of Health andHuman Service Awards, a Lifetime
Achievement Award for FilovirusScience and the Distinguished
Alumnus Award from Kansas State.
(03:29):
Very exciting to me, drKayser's career is taking him to
outbreak zones in Asia, africa,south America and the Middle
East, and he continues to serveas a consultant on biosafety and
laboratory design fororganizations worldwide.
Consultant on biosafety andlaboratory design for
organizations worldwide.
His legacy is not only inscience but also in generations
(03:49):
of researchers he has mentoredand inspired.
So we're all very excited tohave a pioneer here in virology
and a true leader in globalhealth security here.
Welcome, tom.
How are you today?
Good Pleased to be here, allright, excellent, camille, do
you want to start us off withsome of the questions?
Speaker 5 (04:05):
Absolutely so.
Again, thank you so much forjoining us.
We're super excited to have youhere, because we're talking
about something that's reallybeen in the news lately.
We've wanted to do this episodefor a while, but since you are
really the expert in the room onthis topic, could you define
for our listeners whathantaviruses are and how they
spread?
Speaker 6 (04:26):
listeners what hantaviruses are and how they
spread.
Well, hantaviruses are arodent-borne zoonotic disease
that really depend on rodentreservoirs that are chronically
infected with the virus andthey're pretty much worldwide in
distribution.
Often the viruses areassociated with specific rodents
and that's usually regional innature.
Probably the Western medicine'smost familiar with it because
(04:49):
of what happened during theKorean War, which was that HFRS
hemorrhagic fever, renalsyndrome became a problem for UN
troops in the Korean War in the50s, discovered more recently
than that that there were otherhantaviruses in other regions,
again usually associated withspecific rodent species, that
(05:11):
can become seasonal issues ofsome importance.
Speaker 5 (05:16):
And from my understanding hantaviruses
weren't found in the UnitedStates until the Four Corners
outbreak in 1993.
Speaker 6 (05:22):
That's not exactly true.
Speaker 5 (05:24):
Not exactly true, okay.
Speaker 6 (05:25):
No, because we have rats and there's a rat-borne
virus called SOUL.
That's associated with theRattus norwegica, which is
worldwide distribution, andalong with the rats, the virus
was distributed from, whateverits original origin, which is
thought to be Asia original.
Speaker 5 (05:44):
Okay, and have we seen outbreaks of that in the
United States?
Speaker 6 (05:48):
There are occasional cases, usually associated with
laboratory rats or rats that arebeing maintained for one reason
or another.
Speaker 5 (05:57):
Okay, but the first true outbreak, is it correct
that it was the Four Cornersoutbreak in 1993?
Speaker 6 (06:02):
There's another Hanoverse that was known about.
That occurs in wild rodents inthe US, before that associated
with voles.
Speaker 5 (06:09):
Okay, but you were instrumental in finding out what
was happening during the FourCorners outbreak.
Speaker 6 (06:14):
Yeah, it's an interesting story.
I was a part of discoveringwhat it is and the basis for
that was I had been in themilitary at Fort Dedrickrick and
we were interested in Koreanhemorrhagic fever because we
have troops there and there wereoutbreaks.
For instance, in 87, I believeit was I responded to Okinawa
(06:36):
after a large outbreak in anexercise that had occurred there
involving the third Marinesthat had deployed from Okinawa
to Korea, and then, as theybegan to deploy back to Okinawa,
there were cases occurring bothat Korea and then when they
returned to Okinawa and I and acouple of epidemiologists and a
(07:00):
couple of lab people who workedfor me went and set up a lab in
Okinawa to diagnose that.
What year was that?
86 or 87.
Okay?
Speaker 5 (07:11):
I do want to dive more into the Four Corners
outbreak.
Could you set the scene forwhat exactly happened that led
to it?
Speaker 6 (07:17):
There was a sort of mysterious disease that popped
up.
I found out about it I hadgiven an awards lecture at CDC
and went up afterwards to tip abeer and somebody one of the
leaders in the Division of Viraland Rickettsial Diseases
approached a group of us andstarted talking about this
(07:38):
outbreak that occurred and itwas in the popular press already
.
I think there was an article inPeople magazine about cases
occurring and a few deaths thatoccurred by that time and
generally it began to befrightening for the local
population.
Press articles began to appear,they spread to the national
(08:00):
press and CDC became interestedin it.
One reason was that a lot ofthe cases not strictly but a lot
of the cases were occurring onIndian reservations.
So Indian Health Service is afederal institution and so I
think we were contacted CDC atlarge by them.
Speaker 5 (08:21):
And so, from what I was looking back on documents of
this outbreak, finally, thiswas linked to rodents, right?
How did that come about?
Speaker 6 (08:29):
We knew the history of other hantaviruses first of
all Discovering.
It was a hantavirus, and one ofthe things that was unique
about this particular outbreakwas that it was primarily a
pulmonary syndrome, not a kidneydisease, which the previous
hantaviruses largely wereassociated with hemorrhagic
fever, with renal syndrome thatbeing one of the prominent names
(08:52):
for the syndromes, for thediseases that occurred in Asia,
and there was not a lot ofthought about hantaviruses.
And then, when CDC wascontacted, eventually some
specimens came and CDC put afull court press on testing for
a lot of different agents, andso I think we were probably one
(09:15):
of the ones that received thematerial, because we operated a
variety of high containmentlaboratories, and so the
specimens often came and wedistributed those to other
laboratories that did a varietyof testing.
This was really before PCRexisted.
It does play a role in this,but it wasn't a widely used
assay with commercial sorts ofkits and stuff available at the
(09:40):
time.
And so specimens weredistributed to a variety of
people and we set up forhemorrhagic fevers, the agents
that we were responsible for.
Flu was one of the initialthoughts, and so the flu branch
and a few other bacterialdiseases all of them were doing
testing, and what happened isthat I had been involved in drug
(10:01):
trials for treating Koreanhemorrhagic fever that were
occurring in China, and so wehad developed some newer tests
by that time, and so those testswe had brought myself and Dr
Peters, having moved from USAMRAto CDC some of that testing
technology with us, and weapplied that to this particular
(10:22):
outbreak, and we got hits withhana viruses so, tom, the
specimens that you mentioned,were they those human specimens
or were they, did they know atthat time, to look for the roads
came?
later.
Okay, it was just, and thereweren't that many.
There were, you know, five orsix cases that we had serum
samples, primarily on yeah butenough to be scary for sure.
Speaker 5 (10:41):
I was looking at the old articles from that.
Speaker 6 (10:43):
People were afraid were afraid I don't think the
people in the lab werenecessarily afraid to deal with
it, the public was developingsome angst over this.
Speaker 5 (10:52):
Yes, for sure.
And back to the rodents.
Something I read was that whenrodents in the region were
eventually tested, up to 30% ofthem were carrying a hantavirus,
but they weren't necessarilydying.
So why do we see that it's notreally necessarily harming
rodent hosts the way it'sharming a human host?
Speaker 6 (11:09):
The general thought about different sorts of
reservoir hosts for a variety ofpathogens are that there's a
sort of a mutualism thatdevelops with a pathogen that
depends on its survival for arodent host, so that these
rodents become chronicallyinfected.
It's not that it doesn't haveany effect on a variety of
(11:32):
metabolic or other courses, butit doesn't kill them and it
spreads in the population.
The other important part ofthis is it's probably not
present at the prevalence ratesthat you just mentioned 30% but
there had been an event peoplecall it a cascade of events that
created a very high density inpopulations because of natural
(11:55):
resources being available to therodents higher than normal and
denser than normal, andtherefore transmission among a
denser population of theparticular rodent host that's
involved in this was higher andled to those high prevalences.
And that's cyclical because thenatural resources the rodents
(12:17):
depend on are dependent on theresources that go up and down
with climatic or weatherconditions.
Speaker 4 (12:26):
So was this strictly weather or climate related, or
was this some anthropogenicinfluence that humans had
modified the environment?
I don't think this wasanthropogenic.
Speaker 6 (12:35):
It's masting and conifers, I think, was what a
lot of people felt wasresponsible, so that pine nuts,
for instance, was one of thethings that's often made Got you
and so those kind of thatcascade is probably why we saw
the spillover into humans then.
There are a couple reasons whyhumans are involved.
The rodent host this is what'scalled the deer mouse or
(12:57):
Pyramiscus maniculatus.
It's a generalist and it mayactually prefer things like
(13:21):
human.
They have were thought to beparticularly accommodating
towards the rodent host, so therodents could be out there and
be infected infected.
But it's really that they bringthemselves into close
association with humans, or thathumans are injecting themselves
into circumstances where therodent contact can occur, and
(13:43):
that's where the fact that therodents are found in these human
habitations plays a role inthis.
Speaker 5 (13:49):
And I want to make sure we're talking about the
Four Corners outbreak, but thatgeography might not be widely
known, so can you talk moreabout what exactly we're talking
about with these four states?
Speaker 6 (13:58):
The name Four Corners comes from the fact that four
states intersect in the regionin which the outbreak was
occurring.
Speaker 5 (14:06):
So to pivot from the geography of this and what might
have caused that originalspillover, why do we see
something like rodents infectinghumans but we don't have any
human transmission of thatparticular hantavirus?
Speaker 6 (14:17):
Yeah, through the sort of medical history of
hantaviruses as we knew them atthe time, human-to-human
transmission is just not part ofthe story.
There have been a couple ofinstances where in particular a
virus called Andes has had somesecondary transmission from
patients that are infected.
But it's not a population whereit gets into the community and
(14:42):
there's human-to-humantransmission Largely care of
patients.
That's true of a lot ofhemorrhagic fevers where they're
not being transmitted in thegeneral community but only by
close contact.
You see it infected and Andesis probably the only one that's
really noted.
Speaker 4 (14:58):
Yeah.
So, Tom, you mentioned thatbefore CDC got involved it was
already in the popular press,right?
You mentioned that there wasthis unknown disease.
Did they have a name for thatdisease, Because sometimes the
popular press likes to come upwith?
Speaker 6 (15:10):
names right.
Yeah, I think they were callingit Navajo something or another,
and the Navajo Nation didn'tlike that.
Speaker 4 (15:17):
No, of course not.
Navajo flu, I think Interesting.
And then the virus ended upwith the name Sinombre, right?
Speaker 6 (15:24):
So no name there's a fairly large story behind that.
Generally, I was trained inarbovirology and the people I
worked with were largelyarbovirologists, some of who had
strayed over into thehemorrhagic fever arena.
But arboviruses traditionallyhave been named after the
location where the first isolatewas made, so that could be a
(15:45):
river.
Ebola was named after a river.
It could be a town or it couldbe a forest or something like
that, and the Four Corners wasone of the first names proposed,
I think another name which wewho are working with it were
somewhat attracted to was one ofthe locations, was a place
called Muerto Canyon, and I'mtrying to think of another one,
(16:08):
but Sonombre, it turns out, wasa tongue-in-che, cheek approach
because there was controversyabout giving this a name.
Sinombre is no name, no name,but there are actually locations
you can find on maps calledSinombre.
So that was our approach tonaming it without really giving
(16:30):
a specific location oh,interesting Okay.
And that one at least stuck.
Nobody seemed to raise anobjection to it.
There are mountains and skiresorts and street names called
Sanombre, but we weren'ttargeting a specific place in
the way it's traditionally done.
Speaker 5 (16:49):
Gotcha.
Speaker 6 (16:49):
So again, it was a tongue-in-cheek approach to
dealing with the objection tousing a name associated with an
area or something that theChamber of Commerce didn't like.
Speaker 5 (17:01):
Oh, okay, can you tell us how Sinombre causes
hantavirus cardiopulmonarysyndrome, because that's unique.
As you were saying, mosthantaviruses is like a renal
thing and this was different.
Speaker 6 (17:10):
Yeah, the pathogenesis is probably pretty
similar in terms of the diseaseand the organ system involved,
but this one seemed to be morein the tissues of the lungs and
the way it creates a problem isthat the capillaries in
particular are affected by thevirus.
It's not a particularly lyticvirus, but it upsets the ability
(17:34):
to keep fluids in onecompartment or the other, and so
you get this capillary leaksyndrome and eventually what
happens is you fill the alveoliof the lung with fluids and
therefore you lose the abilityto respirate.
One of the solutions initiallythey probably put you on oxygen,
(17:56):
but another solution, which islast ditch measure, was to put
them on, essentially, a heartlung machine.
Speaker 4 (18:04):
Yeah, like extracorporeal oxygenation.
Yeah, I know what you mean.
Speaker 6 (18:10):
ECMO extracorporeal membrane oxygenation yes, it's a
salvage technique, essentiallythat if you let these diseases
progress, eventually you getbetter.
But if your kidneys quitfunctioning you may be in big
trouble.
But if you can get them throughit, by doing dialysis, for
instance or, in this instance,using ECMO- Okay, so once people
(18:34):
were exposed whether these micewere coming into their
dwellings, what was theincubation time?
Speaker 5 (18:39):
And then it's usually an exposure to mouse urine and
mouse feces, correct, that getsaerosolized.
Speaker 6 (18:44):
Yeah, the thought is probably that there's dust,
people have been exposed I thinkthere's instances where they
had wounds and it may have beena percutaneous exposure but
primarily the excreta of therodents.
And a common scenario I thinkyou're going to bring up a
recent outbreak is that people,in the spring in particular,
(19:06):
will go into a seasonal dwelling, a cabin or something like that
, and then clean it up and therodents have, during the
wintertime, taken residence andthey've contaminated it with
their excreta and then clean itup and the rodents have, during
the wintertime, taken residenceand they've contaminated it with
their excreta.
It's probably not fecesactually, it's actually the
urine where it's being excreted.
Gotcha, okay, they often.
(19:27):
If they defecate, they'll oftenurinate at the same time.
It may appear to be feces, butit's probably the urine.
Speaker 4 (19:36):
So as virologists bunia virus virologist I'm
curious.
Bunia viruses are typically notvery stable, but in a
protein-rich matrix, like maybeurine or feces mixed with urine,
they are stable for a longperiod of time and can form
aerosols.
Speaker 6 (19:52):
Drying helps to create the aerosol, and then the
human activity of trying toclean it up is probably what
gets the dust up in the air thatmay infect people.
Gotcha.
Speaker 5 (20:04):
So could you tell us what other hantaviruses are
present in the United States?
Speaker 6 (20:09):
Prior to this, again these rat-borne viruses were
present.
And then this vole virus thatwas found in the northeastern US
.
No diseases have ever beenassociated with it yet, but it
does occur in the volepopulations.
And then after this outbreak inother regions we actually
discovered cases that wereassociated with other Sigma
(20:30):
dantian rodents here in the US.
So one in upstate New York wasassociated with a close relative
of Peromyscus species, but notthe same one.
Leucopus is the name of thatspecies.
And then we found down in thesoutheast a couple of other
sigmadontine rodents that alsoare infected with similar but
(20:54):
distinct viruses that causecases Not as common.
You have to actually thinkabout it.
Pyramiscus maniculatus isprobably the most common and the
largest population of rodentsin the US.
So one of the mysteries aboutthis is why was this disease
only discovered in 1993?
Speaker 1 (21:13):
Yeah, indeed.
Speaker 6 (21:13):
Because this rodent's been there.
This is not a new phenomenon.
One of the things that we diddo in the midst of this was we
got museum specimens and lookedback at rodents and you could
find the presence of the rodents.
I think the specimens were backinto the 60s and I think we
actually found a couple of casesof Hanna-Weir's pulmonary
(21:34):
syndrome by looking at fixedtissues that had been preserved.
Somebody had recognized oh, wesaw a case like this going back
again, I think, to the 60s.
Speaker 5 (21:44):
Yeah, wow, and so do you think without the federal
government getting involved?
You said this was like theIndian Health Service and the
CDC, and these are like peoplethat are coming together.
Would they have found thecausative agent of this?
Speaker 6 (21:55):
Well, you know, the hantavarsas weren't something
people thought about here.
So one of the reasons I thinkthat our group was successful is
that I'd been in a group wherehantavarsas were very much what
we had done.
I had developed some newdiagnostic techniques, largely
to deal with some of the drugtrials that we were doing in
China at the time to deal withsome of the drug trials that we
(22:15):
were doing in China at the time,and so that was a good
combination, but those weren'tthings that universities in
general were involved in.
So, yeah, having a centralnational public health
laboratory that deals in exoticthings that's part of the
mission, of why they're createdis very important.
Unfortunately, right now itain't looking real good for the
(22:36):
maintenance of a lot of thisstuff.
Speaker 1 (22:38):
Yeah, yeah.
So I had some questions for you, building off of what you were
discussing earlier about theisolation of some of these
samples containing viruses thatwould cause HPS in fixed tissues
.
And going back looking throughthese museum specimens, it seems
like a possible concern wouldthen be, even now, possible
(23:00):
underreporting of hantaviruscases.
Do you think that there's stilla need for increased
surveillance in the US or inother parts of the world?
Speaker 6 (23:08):
If you think about the outbreak in particular, it
was very pretty dense in thepopulation, particularly on the
Indian reservations, but in thegeneral population not so much.
There are cases we're going totalk about some, I think, in a
little bit but there are casesevery year and it does go up and
down.
If you look at theirpublications about the cyclical
(23:30):
occurrence of Hanovaris, you'llsee that there is a cyclical
thing that's based again on thiscycle in the rodents and how
many of them and the prevalenceof infection, so that in years
when there aren't particularlydense populations of the rodents
and the Hanoover's prevalencein the rodents isn't high, you
don't tend to get so manyinfections.
(23:50):
And 93 just happened to be oneof the years in which this was
particularly high and it emergedin a specific population that
had pretty high potential forexposure.
And it did and it made thepress and that's probably what
led to its discovery, if that'sthe right term to use.
Speaker 4 (24:12):
And so antiviruses, like other viruses too, are
linked to the weather phenomenonEl Niño or La Niña, right, and
is science good enough topredict when we have another La
Niña coming up, or is thetransmission cycle and the
reservoir activity too complexto predict when we have another
La Nina coming up, or is thetransmission cycle and the
reservoir activity too complexto predict?
We actually?
Speaker 6 (24:30):
spent a fair amount of effort.
You can correlate theprevalence in the rodents or the
amount of infection in therodents to human cases I mean
they are co-joined but trying topredict that in some very
finite way.
We made a number of attemptswith modeling.
We could always fit it prettywell, but we couldn't
(24:51):
necessarily predict it.
Speaker 1 (24:55):
Something I was also wondering about, especially in
light of what you've mentionedabout some of these cyclical
peaks and valleys, if you will,in terms of the epidemiological
trends with hantavirus, is everyyear we see a number of reports
in the news of hantavirus casesamong, say, hikers or among
individuals who you know, given,as you mentioned the somewhat
peridomestic nature of deer mice, that cases that might come up
(25:19):
during the course of springcleaning, right.
So what are some of the beststrategies you think that
Americans should be aware of andshould take in order to reduce
the prospect of thisrodent-human transmission as
they go about these sorts?
Speaker 6 (25:30):
of activities.
There was an effort to try andlook at communicating the ways
of modifying human behavior byways to clean out a cabin, for
instance, particularly in theregions where this was really
important, and I think we made afilm video about that.
Was actually won some sort ofaward for public health
(25:51):
communication.
Speaker 5 (25:52):
We'd love to hear it.
Speaker 4 (25:53):
Are you in?
Speaker 6 (25:54):
it.
Tom, Are you starring in it?
I was part of the process ofproducing it.
I don't think I was in it.
They had talking heads and Iwasn't one of them.
They had talking heads and Iwasn't one of them.
So there are approaches.
I mean, you can't eradicate therodents.
One of the efforts was torodent-proof dwellings, for
instance.
Speaker 1 (26:13):
Yeah, of course.
Speaker 6 (26:14):
The hogans are a traditional type of dwelling on
the Indian Reservation, so wemade efforts to try and help
them deal with excluding rodentswith that environment.
Some of the first casesoccurred in mobile homes.
That was a very repeatablephenomenon during the outbreak
(26:38):
and since, for that matter.
So there have been outbreaks atother national parks having to
do with cabins as well.
Speaker 1 (26:43):
So it's really a matter of trying to keep the
rodents where they belong, intheir natural habitats, versus
now taking up residence inhuman-created environments that
they like Certainly something tobe aware of, going forward when
it comes to, say, cleaning outthese sorts of cabins or making
sure that they're in a positionthat is really fit for human
(27:06):
habitation.
You know, something that alsohas been a point of concern, of
course, is that there are novaccines for any of these new
world hantaviruses that havereceived clinical approval.
But are there any vaccine ormedical countermeasure
candidates that have seenpromising results thus far, and
what aspects of hantavirustransmission or hantavirus
biology lend themselves to beingareas of interest when it comes
(27:27):
to countermeasure development?
Speaker 6 (27:29):
There actually have been vaccines created not here
in the US.
There have been work towardsthat ends, and there are
pharmaceuticals that, if you'retalking about hantaviruses in
general, are successful.
One of the issues with thisparticular outbreak, sanombre
virus, is that the progressionof the disease, from the first
prodromal occurrences, that is,maybe fever, to a very serious
(27:55):
syndrome of pulmonaryinsufficiency, is so rapid that
when we tried a drug trial withribavirin one of the compounds
was the subject of some of thedrug trials we were involved in
China was showing that ribavirinwas effective for HFRS.
And again, it's a matter of youhave to treat early in order to
(28:16):
be effective.
If you wait, it don't work sowell, and with this one, the
time from the first clinicalsigns appearing until being a
whiteout on an X-ray is clearthat it doesn't appear that
ribavirin had a great chance ofsuccess.
Speaker 4 (28:35):
So, tom, you mentioned that the effects of
the pulmonary symptomology isdriven by the immune system,
right, that the immune system iscreating this influx of fluids,
and so on.
Have there been studies onsuppressing the immune system as
a treatment option at thatstage?
Speaker 6 (28:51):
It's really thought that I wouldn't say immune
response, but maybe the primaryimmune response has something to
do with cytokine storms.
Cytokines that when the cellsare infected forms cytokines,
that when the cells are infectedthey then create this
permeability of the barriersthat keep fluids on one side of
(29:12):
the blood barrier.
It's looked at but I thinkagain having a direct effect on
that.
Steroids have been used formany things to help reduce
inflammation.
I think they were tried.
I don't think there was greatsuccess in the instances when it
was supplied.
In this instance People knewabout ribavirin and there was
created sort of an emergency NDAto try ribavirin.
(29:36):
But again, the problem is thatthe time from onset to a very
serious disease doesn't allowtime for the antiviral to really
have much effect on reducingthe effects of the virus.
Speaker 5 (29:48):
Yeah, and I think that's something we come across
pretty consistently in thepublic health and infectious
disease sphere is thatprevention is so much more
effective than us trying to havea cure or something that can
really reduce kind of thismorbidity and mortality that we
see that these diseases causeonce somebody has been infected.
Speaker 4 (30:05):
Antiviruses have been in the news lately.
Right, most of us have seen thesurprising news of the hackmans
in New Mexico.
Tom, can you give us a summaryof the case, of what happened?
Speaker 6 (30:16):
I don't know anything more that you can read in the
newspaper and it's been covered.
I think now, a month or furtherafter the incident occurred,
that the wife who was the oneinfected with Hanna virus
Hackman himself was not waslooking on the Internet for not
necessarily for Hanna virus,whether she had Hanna virus,
just a respiratory syndrome thatwas precipitated.
Speaker 5 (30:39):
Like COVID and flu.
Speaker 6 (30:40):
As I understand the scenario, he was incapacitated
with Alzheimer's anAlzheimer's-like syndrome and
depended for his care on hiswife, and then she went down and
that eventually led, it wouldappear, to his demise.
Speaker 5 (30:59):
Yes, it was Betsy Arcara Hackman.
She was a businesswoman, areally well-known classical
pianist, and she was married toHackman and then eventually
recently passed, in February,from hantavirus and they're
still not quite sure what theexposure was, because rodents
weren't found in the home.
And could you talk to us a bitabout how might people be
contracting hantavirus if notthrough what we would normally
(31:20):
consider exposure, if there'sthat exposure to urine or things
like that of rodents?
Speaker 4 (31:24):
I think one bit of information that I saw come out
just a couple of days ago is, Ithink, that they were trapping
rodents on the premises, and Ithink there were quite a few.
Speaker 1 (31:33):
Yes, I believe I saw some reports that they would
trap some in some of theoutbuildings In the outbuildings
, yeah.
Speaker 6 (31:37):
Outbuildings are often part of the story as well
that you might go to anoutbuilding and do something
there I don't know whether theyhad horses or other animals and
cleaning up again might raisegenerally, somehow being exposed
to an environment that therodents have been in with some
frequency I mean just walkingdown a trail where a Pyramiscus
(32:01):
is jobbed across the trail isnot going to get you.
That's good to know.
Speaker 5 (32:05):
That's good to know.
That's good to know.
I was actually out hiking theother day in Galveston.
I was with a friend and we sawthese massive Galveston rats and
my immediate thought washantavirus.
Speaker 6 (32:15):
That was my immediate thought.
Speaker 5 (32:16):
I don't even know if there's hantavirus here in
Galveston, but like I saw therat and I was immediately like
no, I don't want to be anywherenear it.
But yes, good to know thatthat's not exposure.
Speaker 6 (32:26):
Well, in an outdoor space I mean if it's an aerosol
infection the concentration ofthe particles is much higher in
an area that's closed off, noventilation.
Oh yeah, so that's part of thestory, we believe.
Speaker 4 (32:40):
Yeah, yeah, I was just looking at the timeline of
events the other day and howrapid the progression was of her
demise.
Right, I think in the morningshe was still like Googling
oxygen tanks on Amazon andthings like that and was still
seen at a store.
And then I think the next day Idon't know what they used I
guess her like phone activity orlike her computer activity or
(33:03):
something like that, or likephone activity or like a
computer activity or somethinglike that.
Speaker 6 (33:06):
I should mention it was a video presentation on a
site called we Were there thatCDC runs and it was I think the
20th anniversary of theoccurrence of this outbreak, and
so there's a variety of thingspresented.
Jay Butler presented sort of theclinical aspects of this and
some of the early epidemiologicparts.
(33:27):
I talked about the laboratorydiagnosis and then Jamie Child
talked about the follow-up withthe rodents and absolutely
demonstrating what the rodentreservoir was and how that
played out during this epidemic.
So if you're really interestedyou should visit that site.
You guys can somehow link it inthe show notes.
(33:47):
We'll put it in the show notes.
Speaker 4 (33:48):
Yeah.
Speaker 5 (33:49):
And I was wondering another case that I don't think
has been as widely picked up bythe media, but there's been
three hantavirus-linked deathsin the news from Mammoth Lakes,
california.
So it's a town that they dooften see a case or two in the
spring, as you mentioned, butthree deaths this early in the
spring is pretty surprising forthem.
Just for our listeners, we'rerecording this at the end of
April in 2025.
(34:10):
And so right now these deathsaren't linked to activities that
are usually associated withexposure.
There's not been instanceswhere they were necessarily
cleaning out a cabin orsomething like that If it's not
through a normal exposure I knowyou mentioned that there can be
kind of exposure through likewounds or something like that Is
there any other way that peoplewould become exposed to
hantavirus?
Not that?
Speaker 3 (34:30):
I know of, not that you know of.
Speaker 5 (34:31):
Okay, this has been a brilliant overview on
hantaviruses.
I have learned so much.
Thank you so much for answeringall of our questions.
I do have one more question, ifthat's all right, and it's not
related to hantaviruses virusesbut I didn't realize that you
were one of the co-discoverersof SARS, which is really wild,
and I think that's probably, asyou know, an infectious disease.
Geek, I feel like SARS isprobably one of the things that
(34:51):
originally got me interested ininfectious diseases, because it
was that perfect example of youknow.
You have something and ourhealth is so globally
interconnected.
Now, what was that like to bethere as that was coming out?
Because I think in the news,all the articles that I've ever
seen from that time were veryfear-mongering and people were
very afraid.
So what was that like?
Speaker 6 (35:10):
Again, this one did involve community.
Speaker 5 (35:14):
Yes.
Speaker 6 (35:15):
The original part of the story was that we at CDC
knew there was something goingon in China, in southern China,
knew there was something goingon in China, in southern China,
and I think that the assumptionat the time was this was H5N1,
which goes back to 97.
We're now talking about, for us, the spring of 2003, that
(35:37):
there's something bubbling upand there were efforts made to
try and figure out what that was, to help the Chinese, which
weren't working terribly wellRight now.
This week, who has announcedthat there's a new set of
pandemic preparednessregulations that are finally, I
(35:57):
guess, finalized, that will bepresented to the World Health
Assembly, and part of this is tomake sure that if there's
something bubbling up that haspandemic or real epidemic
potential, that you report it tocentral authorities so that
international efforts to keep itlocalized or from becoming a
(36:18):
pandemic can occur.
And what happened in 2003 wasthat again, the notion that
there was something happening insouthern China was already
apparent.
We made an attempt to help insome way.
So somebody from the flu branchat CDC was actually sent to
China and I don't think I'mgoing to offend China at the
(36:41):
moment, but he was stonewalled.
He went and sat and essentiallywas offered no ability to talk
to anybody or review any data.
And shortly after that,something was starting in Hong
Kong or actually in Vietnam wasthe story, but it emanated from
(37:29):
a physician from Guangdongprovince having traveled to Hong
Kong for his daughter's weddingand staying up in a hospital
that then began to infect otherpatients and that was reported
by a WHO epidemiologist workingthere.
The epidemiologist himselfbecame infected.
He then traveled to Bangkok andwe obtained because we had some
HIV folks present in Thailandspecimens from him that were
sent to Atlanta, and those werethe specimens that I believe
(37:54):
were the actual earliestdetermination of the etiology of
this as being coronaviruses,interesting Coronavirus.
Speaker 4 (38:03):
Yeah, yeah, tom, you brought up the pandemic
agreement.
Right, that's finally, afterthree years, been finalized.
But do you think countries willstick to that agreement and
will Well after SARS?
Speaker 6 (38:14):
you have to realize that they strengthen the world
health regulations and part ofthat was to strengthen reporting
.
But in this instance and partof that was to strengthen
reporting, but in this instanceonce again, things didn't happen
the way they were.
I would say first of all thatSARS was bad, but once it was
discovered what it was, therewas follow-up and the natural
(38:39):
sort of reservoir and probablythe means of that becoming a
human transmitted disease waspretty well worked out.
If everybody wants to recallthe circumstances, I would say,
once the virus got to Wuhan atleast as far as I can tell, the
Wuhan Institute of Virology,whose name is MUD right now,
(39:03):
probably unjustifiably actuallycontacted people from the
outside and revealed thesequence of the virus and that
it was another virus.
Part of, unfortunately, thepolitical environment was that
the Chinese Communist Partyclamped down on the
(39:23):
dissemination of information andhave also suppressed other
investigations, including byinternational bodies such as WHO
, and that's the part thatsticks in everybody's craw.
Speaker 5 (39:38):
So if I can ask, because you've been present for
many outbreaks, you've helpedwork on them, you've really
contributed and helped keeppeople safe from a public health
perspective, to you, what doyou think makes or breaks an
effective outbreak response,whether that's hantaviruses,
whether that's SARS?
What does that look like?
Speaker 6 (39:56):
Figuring out what it is early and then figuring out
whether there arecountermeasures or social things
that can be done to diminishtransmission is probably the
most important.
I would use an example Ebola andthe West African outbreak.
So what happened in thatoutbreak is that outbreak
(40:16):
probably began in 2013 andessentially became disseminated
to three countries before it wasever identified as Ebola.
And holding up that same example, we had been involved at CDC
and special pathogens inparticular, in an outbreak that
(40:37):
occurred in 2000 in Uganda inGulu, and a lot of lessons were
learned from that.
Part of it was that we had apermanent presence special
pathogens in a PEPBAR CDC unitat the National Institute of
Virology in Uganda, and there'sa paper published about a number
(41:01):
of outbreaks of both Marburgand Ebola Sudan that occurred in
Uganda and that laboratorypresence had allowed the very
early identification and we hadtrained up people how to respond
early and how to isolate casesof Ebola so that they're being
(41:22):
taken care of by people who arewearing appropriate PPE, so that
there's not transmission toother people who aren't nursing
and using appropriate protectiveequipment.
And that's the key with Ebola,it's not something that
circulates in the community.
It's circulated by patientsthat become infected, have high
(41:44):
loads of virus and people thatare intimately exposing
themselves to them, then get it,and that chain goes on.
Speaker 4 (41:51):
Yeah, it's a caretaker's disease, like Paul
Farmer always says.
Yeah, all right.
Speaker 5 (41:57):
Thank you so much.
This was brilliant.
I've learned so much.
Again, we cannot thank youenough for taking the time to
come speak with us.
It's really rare and excitingto get such a well-versed expert
on the podcast.
So thank you for taking thetime, Dr Kysak Really appreciate
it.
Speaker 6 (42:10):
You're welcome, my pleasure, thank you.
Thank you.
Speaker 5 (42:13):
All right, and thanks for joining us for this episode
of Infectious Science.
As always, let us know what youwant to hear, and thanks for
listening.
Speaker 3 (42:19):
Thanks for Infectious Science podcast.
Be sure to hit subscribe andvisit infectiousscienceorg to
join the conversation, accessthe show notes and to sign up
for our newsletter and receiveour free materials.
Speaker 2 (42:30):
If you enjoyed this new episode of Infectious
Science, please leave us areview on Apple Podcasts and
Spotify, and go ahead and sharethis episode with some of your
friends.
Speaker 3 (42:38):
Also, don't hesitate to ask questions and tell us
what topics you'd like us tocover for future episodes.
To get in touch, drop a line inthe comments section or send us
a message on social media.
Speaker 2 (42:48):
So we'll see you next time for a new episode, and in
the meantime, stay happy stayhealthy, stay interested.
Speaker 3 (43:03):
Thank you.
This is a podcast about One Health the idea that
the health of humans, animals,plants and the environment that
we all share are intrinsicallylinked.
Speaker 3 (00:17):
Coming to you from the University of Texas Medical
Branch and the GalvestonNational Laboratory.
Speaker 2 (00:21):
This is Infectious Science.
Where enthusiasm for science?
Speaker 3 (00:25):
is contagious.
Speaker 4 (00:30):
Welcome back to the Infectious Science podcast.
I'm here today with Dr CamilleLedoux.
How's it going, camille?
When are you moving Next week?
Oh, okay, are you excited?
Yes, I'm very excited.
Nice, has it sunk in yet to be?
Speaker 5 (00:44):
a doctor.
It's weird.
Yeah, it's getting there.
I feel like it's not old, ithasn't gotten old?
Speaker 4 (00:49):
All right, we're missing Christina today.
Yes, we are, but we'recompensating with a special
guest, alex Alvarado.
Alex, how are you?
I'm doing all right, how areyou?
Speaker 1 (01:01):
Yes, so I'm a second year microbiology and immunology
graduate student in the lab ofTom Geisbert and my project is
currently working on developinga recombinant vesicular
stomatitis virus vectoredvaccine for guanarito virus
which causes Venezuelanhemorrhagic fever.
Speaker 4 (01:16):
Okay, so hopefully we'll see or hear more of you on
the podcast.
I certainly hope so.
All right, welcome.
And then we have a very specialguest today and I'm super
excited.
I wanted to record this episodefor probably two years now.
Today's guest is a true giant inthe field of infectious disease
research and global outbreakresponse.
(01:38):
Dr Thomas Kysak is aworld-renowned virologist,
veterinarian and epidemiologistcurrently serving as the
director of high containmentlaboratory operations here at
the Galveston National Lab atthe University of Medical Branch
, where we are here in ourpodcast closet.
Over a remarkable careerspanning more than four decades,
dr Kaysik has been on the frontlines of some of the world's
(02:01):
most significant viral outbreaks, including Ebola, marburg,
nipah, rift Valley Fever, sarsand the topic of today's session
, hantaviruses.
He's been credited to be one ofthe co-discoverers of SARS
coronavirus in 2003 during theoutbreak back then, and Dr
(02:21):
Kaysack's expertise is rooted ina unique blend of veterinary
medicine, military service andlaboratory science.
After earning his DVM fromKansas State University, he
embarked on a distinguished21-year military career with the
US Air Force and Army, workingin research stations around the
world, ultimately retiring as alieutenant colonel.
(02:42):
Ultimately retiring as alieutenant colonel.
Following his retirement fromthe military.
He joined the Centers forDisease Control and Prevention,
where he was part of theleadership team of the Special
Pathogens Branch and coordinatedinternational responses to
emerging viral threats.
And here's the kicker With over300 science publications to his
name and more than 45,000citations, that's incredible.
(03:04):
That's incredible.
Speaker 5 (03:05):
That's wild.
Speaker 4 (03:07):
Dr Kaysack's work has shaped our understanding of
hemorrhagic fever andarthropod-borne viral diseases,
and his rapid diagnosticinnovations have saved countless
lives.
He's obviously the recipient ofmultiple honors, including
three Secretary of Health andHuman Service Awards, a Lifetime
Achievement Award for FilovirusScience and the Distinguished
Alumnus Award from Kansas State.
(03:29):
Very exciting to me, drKayser's career is taking him to
outbreak zones in Asia, africa,south America and the Middle
East, and he continues to serveas a consultant on biosafety and
laboratory design fororganizations worldwide.
Consultant on biosafety andlaboratory design for
organizations worldwide.
His legacy is not only inscience but also in generations
(03:49):
of researchers he has mentoredand inspired.
So we're all very excited tohave a pioneer here in virology
and a true leader in globalhealth security here.
Welcome, tom.
How are you today?
Good Pleased to be here, allright, excellent, camille, do
you want to start us off withsome of the questions?
Speaker 5 (04:05):
Absolutely so.
Again, thank you so much forjoining us.
We're super excited to have youhere, because we're talking
about something that's reallybeen in the news lately.
We've wanted to do this episodefor a while, but since you are
really the expert in the room onthis topic, could you define
for our listeners whathantaviruses are and how they
spread?
Speaker 6 (04:26):
listeners what hantaviruses are and how they
spread.
Well, hantaviruses are arodent-borne zoonotic disease
that really depend on rodentreservoirs that are chronically
infected with the virus andthey're pretty much worldwide in
distribution.
Often the viruses areassociated with specific rodents
and that's usually regional innature.
Probably the Western medicine'smost familiar with it because
(04:49):
of what happened during theKorean War, which was that HFRS
hemorrhagic fever, renalsyndrome became a problem for UN
troops in the Korean War in the50s, discovered more recently
than that that there were otherhantaviruses in other regions,
again usually associated withspecific rodent species, that
(05:11):
can become seasonal issues ofsome importance.
Speaker 5 (05:16):
And from my understanding hantaviruses
weren't found in the UnitedStates until the Four Corners
outbreak in 1993.
Speaker 6 (05:22):
That's not exactly true.
Speaker 5 (05:24):
Not exactly true, okay.
Speaker 6 (05:25):
No, because we have rats and there's a rat-borne
virus called SOUL.
That's associated with theRattus norwegica, which is
worldwide distribution, andalong with the rats, the virus
was distributed from, whateverits original origin, which is
thought to be Asia original.
Speaker 5 (05:44):
Okay, and have we seen outbreaks of that in the
United States?
Speaker 6 (05:48):
There are occasional cases, usually associated with
laboratory rats or rats that arebeing maintained for one reason
or another.
Speaker 5 (05:57):
Okay, but the first true outbreak, is it correct
that it was the Four Cornersoutbreak in 1993?
Speaker 6 (06:02):
There's another Hanoverse that was known about.
That occurs in wild rodents inthe US, before that associated
with voles.
Speaker 5 (06:09):
Okay, but you were instrumental in finding out what
was happening during the FourCorners outbreak.
Speaker 6 (06:14):
Yeah, it's an interesting story.
I was a part of discoveringwhat it is and the basis for
that was I had been in themilitary at Fort Dedrickrick and
we were interested in Koreanhemorrhagic fever because we
have troops there and there wereoutbreaks.
For instance, in 87, I believeit was I responded to Okinawa
(06:36):
after a large outbreak in anexercise that had occurred there
involving the third Marinesthat had deployed from Okinawa
to Korea, and then, as theybegan to deploy back to Okinawa,
there were cases occurring bothat Korea and then when they
returned to Okinawa and I and acouple of epidemiologists and a
(07:00):
couple of lab people who workedfor me went and set up a lab in
Okinawa to diagnose that.
What year was that?
86 or 87.
Okay?
Speaker 5 (07:11):
I do want to dive more into the Four Corners
outbreak.
Could you set the scene forwhat exactly happened that led
to it?
Speaker 6 (07:17):
There was a sort of mysterious disease that popped
up.
I found out about it I hadgiven an awards lecture at CDC
and went up afterwards to tip abeer and somebody one of the
leaders in the Division of Viraland Rickettsial Diseases
approached a group of us andstarted talking about this
(07:38):
outbreak that occurred and itwas in the popular press already
.
I think there was an article inPeople magazine about cases
occurring and a few deaths thatoccurred by that time and
generally it began to befrightening for the local
population.
Press articles began to appear,they spread to the national
(08:00):
press and CDC became interestedin it.
One reason was that a lot ofthe cases not strictly but a lot
of the cases were occurring onIndian reservations.
So Indian Health Service is afederal institution and so I
think we were contacted CDC atlarge by them.
Speaker 5 (08:21):
And so, from what I was looking back on documents of
this outbreak, finally, thiswas linked to rodents, right?
How did that come about?
Speaker 6 (08:29):
We knew the history of other hantaviruses first of
all Discovering.
It was a hantavirus, and one ofthe things that was unique
about this particular outbreakwas that it was primarily a
pulmonary syndrome, not a kidneydisease, which the previous
hantaviruses largely wereassociated with hemorrhagic
fever, with renal syndrome thatbeing one of the prominent names
(08:52):
for the syndromes, for thediseases that occurred in Asia,
and there was not a lot ofthought about hantaviruses.
And then, when CDC wascontacted, eventually some
specimens came and CDC put afull court press on testing for
a lot of different agents, andso I think we were probably one
(09:15):
of the ones that received thematerial, because we operated a
variety of high containmentlaboratories, and so the
specimens often came and wedistributed those to other
laboratories that did a varietyof testing.
This was really before PCRexisted.
It does play a role in this,but it wasn't a widely used
assay with commercial sorts ofkits and stuff available at the
(09:40):
time.
And so specimens weredistributed to a variety of
people and we set up forhemorrhagic fevers, the agents
that we were responsible for.
Flu was one of the initialthoughts, and so the flu branch
and a few other bacterialdiseases all of them were doing
testing, and what happened isthat I had been involved in drug
(10:01):
trials for treating Koreanhemorrhagic fever that were
occurring in China, and so wehad developed some newer tests
by that time, and so those testswe had brought myself and Dr
Peters, having moved from USAMRAto CDC some of that testing
technology with us, and weapplied that to this particular
(10:22):
outbreak, and we got hits withhana viruses so, tom, the
specimens that you mentioned,were they those human specimens
or were they, did they know atthat time, to look for the roads
came?
later.
Okay, it was just, and thereweren't that many.
There were, you know, five orsix cases that we had serum
samples, primarily on yeah butenough to be scary for sure.
Speaker 5 (10:41):
I was looking at the old articles from that.
Speaker 6 (10:43):
People were afraid were afraid I don't think the
people in the lab werenecessarily afraid to deal with
it, the public was developingsome angst over this.
Speaker 5 (10:52):
Yes, for sure.
And back to the rodents.
Something I read was that whenrodents in the region were
eventually tested, up to 30% ofthem were carrying a hantavirus,
but they weren't necessarilydying.
So why do we see that it's notreally necessarily harming
rodent hosts the way it'sharming a human host?
Speaker 6 (11:09):
The general thought about different sorts of
reservoir hosts for a variety ofpathogens are that there's a
sort of a mutualism thatdevelops with a pathogen that
depends on its survival for arodent host, so that these
rodents become chronicallyinfected.
It's not that it doesn't haveany effect on a variety of
(11:32):
metabolic or other courses, butit doesn't kill them and it
spreads in the population.
The other important part ofthis is it's probably not
present at the prevalence ratesthat you just mentioned 30% but
there had been an event peoplecall it a cascade of events that
created a very high density inpopulations because of natural
(11:55):
resources being available to therodents higher than normal and
denser than normal, andtherefore transmission among a
denser population of theparticular rodent host that's
involved in this was higher andled to those high prevalences.
And that's cyclical because thenatural resources the rodents
(12:17):
depend on are dependent on theresources that go up and down
with climatic or weatherconditions.
Speaker 4 (12:26):
So was this strictly weather or climate related, or
was this some anthropogenicinfluence that humans had
modified the environment?
I don't think this wasanthropogenic.
Speaker 6 (12:35):
It's masting and conifers, I think, was what a
lot of people felt wasresponsible, so that pine nuts,
for instance, was one of thethings that's often made Got you
and so those kind of thatcascade is probably why we saw
the spillover into humans then.
There are a couple reasons whyhumans are involved.
The rodent host this is what'scalled the deer mouse or
(12:57):
Pyramiscus maniculatus.
It's a generalist and it mayactually prefer things like
(13:21):
human.
They have were thought to beparticularly accommodating
towards the rodent host, so therodents could be out there and
be infected infected.
But it's really that they bringthemselves into close
association with humans, or thathumans are injecting themselves
into circumstances where therodent contact can occur, and
(13:43):
that's where the fact that therodents are found in these human
habitations plays a role inthis.
Speaker 5 (13:49):
And I want to make sure we're talking about the
Four Corners outbreak, but thatgeography might not be widely
known, so can you talk moreabout what exactly we're talking
about with these four states?
Speaker 6 (13:58):
The name Four Corners comes from the fact that four
states intersect in the regionin which the outbreak was
occurring.
Speaker 5 (14:06):
So to pivot from the geography of this and what might
have caused that originalspillover, why do we see
something like rodents infectinghumans but we don't have any
human transmission of thatparticular hantavirus?
Speaker 6 (14:17):
Yeah, through the sort of medical history of
hantaviruses as we knew them atthe time, human-to-human
transmission is just not part ofthe story.
There have been a couple ofinstances where in particular a
virus called Andes has had somesecondary transmission from
patients that are infected.
But it's not a population whereit gets into the community and
(14:42):
there's human-to-humantransmission Largely care of
patients.
That's true of a lot ofhemorrhagic fevers where they're
not being transmitted in thegeneral community but only by
close contact.
You see it infected and Andesis probably the only one that's
really noted.
Speaker 4 (14:58):
Yeah.
So, Tom, you mentioned thatbefore CDC got involved it was
already in the popular press,right?
You mentioned that there wasthis unknown disease.
Did they have a name for thatdisease, Because sometimes the
popular press likes to come upwith?
Speaker 6 (15:10):
names right.
Yeah, I think they were callingit Navajo something or another,
and the Navajo Nation didn'tlike that.
Speaker 4 (15:17):
No, of course not.
Navajo flu, I think Interesting.
And then the virus ended upwith the name Sinombre, right?
Speaker 6 (15:24):
So no name there's a fairly large story behind that.
Generally, I was trained inarbovirology and the people I
worked with were largelyarbovirologists, some of who had
strayed over into thehemorrhagic fever arena.
But arboviruses traditionallyhave been named after the
location where the first isolatewas made, so that could be a
(15:45):
river.
Ebola was named after a river.
It could be a town or it couldbe a forest or something like
that, and the Four Corners wasone of the first names proposed,
I think another name which wewho are working with it were
somewhat attracted to was one ofthe locations, was a place
called Muerto Canyon, and I'mtrying to think of another one,
(16:08):
but Sonombre, it turns out, wasa tongue-in-che, cheek approach
because there was controversyabout giving this a name.
Sinombre is no name, no name,but there are actually locations
you can find on maps calledSinombre.
So that was our approach tonaming it without really giving
(16:30):
a specific location oh,interesting Okay.
And that one at least stuck.
Nobody seemed to raise anobjection to it.
There are mountains and skiresorts and street names called
Sanombre, but we weren'ttargeting a specific place in
the way it's traditionally done.
Speaker 5 (16:49):
Gotcha.
Speaker 6 (16:49):
So again, it was a tongue-in-cheek approach to
dealing with the objection tousing a name associated with an
area or something that theChamber of Commerce didn't like.
Speaker 5 (17:01):
Oh, okay, can you tell us how Sinombre causes
hantavirus cardiopulmonarysyndrome, because that's unique.
As you were saying, mosthantaviruses is like a renal
thing and this was different.
Speaker 6 (17:10):
Yeah, the pathogenesis is probably pretty
similar in terms of the diseaseand the organ system involved,
but this one seemed to be morein the tissues of the lungs and
the way it creates a problem isthat the capillaries in
particular are affected by thevirus.
It's not a particularly lyticvirus, but it upsets the ability
(17:34):
to keep fluids in onecompartment or the other, and so
you get this capillary leaksyndrome and eventually what
happens is you fill the alveoliof the lung with fluids and
therefore you lose the abilityto respirate.
One of the solutions initiallythey probably put you on oxygen,
(17:56):
but another solution, which islast ditch measure, was to put
them on, essentially, a heartlung machine.
Speaker 4 (18:04):
Yeah, like extracorporeal oxygenation.
Yeah, I know what you mean.
Speaker 6 (18:10):
ECMO extracorporeal membrane oxygenation yes, it's a
salvage technique, essentiallythat if you let these diseases
progress, eventually you getbetter.
But if your kidneys quitfunctioning you may be in big
trouble.
But if you can get them throughit, by doing dialysis, for
instance or, in this instance,using ECMO- Okay, so once people
(18:34):
were exposed whether these micewere coming into their
dwellings, what was theincubation time?
Speaker 5 (18:39):
And then it's usually an exposure to mouse urine and
mouse feces, correct, that getsaerosolized.
Speaker 6 (18:44):
Yeah, the thought is probably that there's dust,
people have been exposed I thinkthere's instances where they
had wounds and it may have beena percutaneous exposure but
primarily the excreta of therodents.
And a common scenario I thinkyou're going to bring up a
recent outbreak is that people,in the spring in particular,
(19:06):
will go into a seasonal dwelling, a cabin or something like that
, and then clean it up and therodents have, during the
wintertime, taken residence andthey've contaminated it with
their excreta and then clean itup and the rodents have, during
the wintertime, taken residenceand they've contaminated it with
their excreta.
It's probably not fecesactually, it's actually the
urine where it's being excreted.
Gotcha, okay, they often.
(19:27):
If they defecate, they'll oftenurinate at the same time.
It may appear to be feces, butit's probably the urine.
Speaker 4 (19:36):
So as virologists bunia virus virologist I'm
curious.
Bunia viruses are typically notvery stable, but in a
protein-rich matrix, like maybeurine or feces mixed with urine,
they are stable for a longperiod of time and can form
aerosols.
Speaker 6 (19:52):
Drying helps to create the aerosol, and then the
human activity of trying toclean it up is probably what
gets the dust up in the air thatmay infect people.
Gotcha.
Speaker 5 (20:04):
So could you tell us what other hantaviruses are
present in the United States?
Speaker 6 (20:09):
Prior to this, again these rat-borne viruses were
present.
And then this vole virus thatwas found in the northeastern US
.
No diseases have ever beenassociated with it yet, but it
does occur in the volepopulations.
And then after this outbreak inother regions we actually
discovered cases that wereassociated with other Sigma
(20:30):
dantian rodents here in the US.
So one in upstate New York wasassociated with a close relative
of Peromyscus species, but notthe same one.
Leucopus is the name of thatspecies.
And then we found down in thesoutheast a couple of other
sigmadontine rodents that alsoare infected with similar but
(20:54):
distinct viruses that causecases Not as common.
You have to actually thinkabout it.
Pyramiscus maniculatus isprobably the most common and the
largest population of rodentsin the US.
So one of the mysteries aboutthis is why was this disease
only discovered in 1993?
Speaker 1 (21:13):
Yeah, indeed.
Speaker 6 (21:13):
Because this rodent's been there.
This is not a new phenomenon.
One of the things that we diddo in the midst of this was we
got museum specimens and lookedback at rodents and you could
find the presence of the rodents.
I think the specimens were backinto the 60s and I think we
actually found a couple of casesof Hanna-Weir's pulmonary
(21:34):
syndrome by looking at fixedtissues that had been preserved.
Somebody had recognized oh, wesaw a case like this going back
again, I think, to the 60s.
Speaker 5 (21:44):
Yeah, wow, and so do you think without the federal
government getting involved?
You said this was like theIndian Health Service and the
CDC, and these are like peoplethat are coming together.
Would they have found thecausative agent of this?
Speaker 6 (21:55):
Well, you know, the hantavarsas weren't something
people thought about here.
So one of the reasons I thinkthat our group was successful is
that I'd been in a group wherehantavarsas were very much what
we had done.
I had developed some newdiagnostic techniques, largely
to deal with some of the drugtrials that we were doing in
China at the time to deal withsome of the drug trials that we
(22:15):
were doing in China at the time,and so that was a good
combination, but those weren'tthings that universities in
general were involved in.
So, yeah, having a centralnational public health
laboratory that deals in exoticthings that's part of the
mission, of why they're createdis very important.
Unfortunately, right now itain't looking real good for the
(22:36):
maintenance of a lot of thisstuff.
Speaker 1 (22:38):
Yeah, yeah.
So I had some questions for you, building off of what you were
discussing earlier about theisolation of some of these
samples containing viruses thatwould cause HPS in fixed tissues
.
And going back looking throughthese museum specimens, it seems
like a possible concern wouldthen be, even now, possible
(23:00):
underreporting of hantaviruscases.
Do you think that there's stilla need for increased
surveillance in the US or inother parts of the world?
Speaker 6 (23:08):
If you think about the outbreak in particular, it
was very pretty dense in thepopulation, particularly on the
Indian reservations, but in thegeneral population not so much.
There are cases we're going totalk about some, I think, in a
little bit but there are casesevery year and it does go up and
down.
If you look at theirpublications about the cyclical
(23:30):
occurrence of Hanovaris, you'llsee that there is a cyclical
thing that's based again on thiscycle in the rodents and how
many of them and the prevalenceof infection, so that in years
when there aren't particularlydense populations of the rodents
and the Hanoover's prevalencein the rodents isn't high, you
don't tend to get so manyinfections.
(23:50):
And 93 just happened to be oneof the years in which this was
particularly high and it emergedin a specific population that
had pretty high potential forexposure.
And it did and it made thepress and that's probably what
led to its discovery, if that'sthe right term to use.
Speaker 4 (24:12):
And so antiviruses, like other viruses too, are
linked to the weather phenomenonEl Niño or La Niña, right, and
is science good enough topredict when we have another La
Niña coming up, or is thetransmission cycle and the
reservoir activity too complexto predict when we have another
La Nina coming up, or is thetransmission cycle and the
reservoir activity too complexto predict?
We actually?
Speaker 6 (24:30):
spent a fair amount of effort.
You can correlate theprevalence in the rodents or the
amount of infection in therodents to human cases I mean
they are co-joined but trying topredict that in some very
finite way.
We made a number of attemptswith modeling.
We could always fit it prettywell, but we couldn't
(24:51):
necessarily predict it.
Speaker 1 (24:55):
Something I was also wondering about, especially in
light of what you've mentionedabout some of these cyclical
peaks and valleys, if you will,in terms of the epidemiological
trends with hantavirus, is everyyear we see a number of reports
in the news of hantavirus casesamong, say, hikers or among
individuals who you know, given,as you mentioned the somewhat
peridomestic nature of deer mice, that cases that might come up
(25:19):
during the course of springcleaning, right.
So what are some of the beststrategies you think that
Americans should be aware of andshould take in order to reduce
the prospect of thisrodent-human transmission as
they go about these sorts?
Speaker 6 (25:30):
of activities.
There was an effort to try andlook at communicating the ways
of modifying human behavior byways to clean out a cabin, for
instance, particularly in theregions where this was really
important, and I think we made afilm video about that.
Was actually won some sort ofaward for public health
(25:51):
communication.
Speaker 5 (25:52):
We'd love to hear it.
Speaker 4 (25:53):
Are you in?
Speaker 6 (25:54):
it.
Tom, Are you starring in it?
I was part of the process ofproducing it.
I don't think I was in it.
They had talking heads and Iwasn't one of them.
They had talking heads and Iwasn't one of them.
So there are approaches.
I mean, you can't eradicate therodents.
One of the efforts was torodent-proof dwellings, for
instance.
Speaker 1 (26:13):
Yeah, of course.
Speaker 6 (26:14):
The hogans are a traditional type of dwelling on
the Indian Reservation, so wemade efforts to try and help
them deal with excluding rodentswith that environment.
Some of the first casesoccurred in mobile homes.
That was a very repeatablephenomenon during the outbreak
(26:38):
and since, for that matter.
So there have been outbreaks atother national parks having to
do with cabins as well.
Speaker 1 (26:43):
So it's really a matter of trying to keep the
rodents where they belong, intheir natural habitats, versus
now taking up residence inhuman-created environments that
they like Certainly something tobe aware of, going forward when
it comes to, say, cleaning outthese sorts of cabins or making
sure that they're in a positionthat is really fit for human
(27:06):
habitation.
You know, something that alsohas been a point of concern, of
course, is that there are novaccines for any of these new
world hantaviruses that havereceived clinical approval.
But are there any vaccine ormedical countermeasure
candidates that have seenpromising results thus far, and
what aspects of hantavirustransmission or hantavirus
biology lend themselves to beingareas of interest when it comes
(27:27):
to countermeasure development?
Speaker 6 (27:29):
There actually have been vaccines created not here
in the US.
There have been work towardsthat ends, and there are
pharmaceuticals that, if you'retalking about hantaviruses in
general, are successful.
One of the issues with thisparticular outbreak, sanombre
virus, is that the progressionof the disease, from the first
prodromal occurrences, that is,maybe fever, to a very serious
(27:55):
syndrome of pulmonaryinsufficiency, is so rapid that
when we tried a drug trial withribavirin one of the compounds
was the subject of some of thedrug trials we were involved in
China was showing that ribavirinwas effective for HFRS.
And again, it's a matter of youhave to treat early in order to
(28:16):
be effective.
If you wait, it don't work sowell, and with this one, the
time from the first clinicalsigns appearing until being a
whiteout on an X-ray is clearthat it doesn't appear that
ribavirin had a great chance ofsuccess.
Speaker 4 (28:35):
So, tom, you mentioned that the effects of
the pulmonary symptomology isdriven by the immune system,
right, that the immune system iscreating this influx of fluids,
and so on.
Have there been studies onsuppressing the immune system as
a treatment option at thatstage?
Speaker 6 (28:51):
It's really thought that I wouldn't say immune
response, but maybe the primaryimmune response has something to
do with cytokine storms.
Cytokines that when the cellsare infected forms cytokines,
that when the cells are infectedthey then create this
permeability of the barriersthat keep fluids on one side of
(29:12):
the blood barrier.
It's looked at but I thinkagain having a direct effect on
that.
Steroids have been used formany things to help reduce
inflammation.
I think they were tried.
I don't think there was greatsuccess in the instances when it
was supplied.
In this instance People knewabout ribavirin and there was
created sort of an emergency NDAto try ribavirin.
(29:36):
But again, the problem is thatthe time from onset to a very
serious disease doesn't allowtime for the antiviral to really
have much effect on reducingthe effects of the virus.
Speaker 5 (29:48):
Yeah, and I think that's something we come across
pretty consistently in thepublic health and infectious
disease sphere is thatprevention is so much more
effective than us trying to havea cure or something that can
really reduce kind of thismorbidity and mortality that we
see that these diseases causeonce somebody has been infected.
Speaker 4 (30:05):
Antiviruses have been in the news lately.
Right, most of us have seen thesurprising news of the hackmans
in New Mexico.
Tom, can you give us a summaryof the case, of what happened?
Speaker 6 (30:16):
I don't know anything more that you can read in the
newspaper and it's been covered.
I think now, a month or furtherafter the incident occurred,
that the wife who was the oneinfected with Hanna virus
Hackman himself was not waslooking on the Internet for not
necessarily for Hanna virus,whether she had Hanna virus,
just a respiratory syndrome thatwas precipitated.
Speaker 5 (30:39):
Like COVID and flu.
Speaker 6 (30:40):
As I understand the scenario, he was incapacitated
with Alzheimer's anAlzheimer's-like syndrome and
depended for his care on hiswife, and then she went down and
that eventually led, it wouldappear, to his demise.
Speaker 5 (30:59):
Yes, it was Betsy Arcara Hackman.
She was a businesswoman, areally well-known classical
pianist, and she was married toHackman and then eventually
recently passed, in February,from hantavirus and they're
still not quite sure what theexposure was, because rodents
weren't found in the home.
And could you talk to us a bitabout how might people be
contracting hantavirus if notthrough what we would normally
(31:20):
consider exposure, if there'sthat exposure to urine or things
like that of rodents?
Speaker 4 (31:24):
I think one bit of information that I saw come out
just a couple of days ago is, Ithink, that they were trapping
rodents on the premises, and Ithink there were quite a few.
Speaker 1 (31:33):
Yes, I believe I saw some reports that they would
trap some in some of theoutbuildings In the outbuildings
, yeah.
Speaker 6 (31:37):
Outbuildings are often part of the story as well
that you might go to anoutbuilding and do something
there I don't know whether theyhad horses or other animals and
cleaning up again might raisegenerally, somehow being exposed
to an environment that therodents have been in with some
frequency I mean just walkingdown a trail where a Pyramiscus
(32:01):
is jobbed across the trail isnot going to get you.
That's good to know.
Speaker 5 (32:05):
That's good to know.
That's good to know.
I was actually out hiking theother day in Galveston.
I was with a friend and we sawthese massive Galveston rats and
my immediate thought washantavirus.
Speaker 6 (32:15):
That was my immediate thought.
Speaker 5 (32:16):
I don't even know if there's hantavirus here in
Galveston, but like I saw therat and I was immediately like
no, I don't want to be anywherenear it.
But yes, good to know thatthat's not exposure.
Speaker 6 (32:26):
Well, in an outdoor space I mean if it's an aerosol
infection the concentration ofthe particles is much higher in
an area that's closed off, noventilation.
Oh yeah, so that's part of thestory, we believe.
Speaker 4 (32:40):
Yeah, yeah, I was just looking at the timeline of
events the other day and howrapid the progression was of her
demise.
Right, I think in the morningshe was still like Googling
oxygen tanks on Amazon andthings like that and was still
seen at a store.
And then I think the next day Idon't know what they used I
guess her like phone activity orlike her computer activity or
(33:03):
something like that, or likephone activity or like a
computer activity or somethinglike that.
Speaker 6 (33:06):
I should mention it was a video presentation on a
site called we Were there thatCDC runs and it was I think the
20th anniversary of theoccurrence of this outbreak, and
so there's a variety of thingspresented.
Jay Butler presented sort of theclinical aspects of this and
some of the early epidemiologicparts.
(33:27):
I talked about the laboratorydiagnosis and then Jamie Child
talked about the follow-up withthe rodents and absolutely
demonstrating what the rodentreservoir was and how that
played out during this epidemic.
So if you're really interestedyou should visit that site.
You guys can somehow link it inthe show notes.
(33:47):
We'll put it in the show notes.
Speaker 4 (33:48):
Yeah.
Speaker 5 (33:49):
And I was wondering another case that I don't think
has been as widely picked up bythe media, but there's been
three hantavirus-linked deathsin the news from Mammoth Lakes,
california.
So it's a town that they dooften see a case or two in the
spring, as you mentioned, butthree deaths this early in the
spring is pretty surprising forthem.
Just for our listeners, we'rerecording this at the end of
April in 2025.
(34:10):
And so right now these deathsaren't linked to activities that
are usually associated withexposure.
There's not been instanceswhere they were necessarily
cleaning out a cabin orsomething like that If it's not
through a normal exposure I knowyou mentioned that there can be
kind of exposure through likewounds or something like that Is
there any other way that peoplewould become exposed to
hantavirus?
Not that?
Speaker 3 (34:30):
I know of, not that you know of.
Speaker 5 (34:31):
Okay, this has been a brilliant overview on
hantaviruses.
I have learned so much.
Thank you so much for answeringall of our questions.
I do have one more question, ifthat's all right, and it's not
related to hantaviruses virusesbut I didn't realize that you
were one of the co-discoverersof SARS, which is really wild,
and I think that's probably, asyou know, an infectious disease.
Geek, I feel like SARS isprobably one of the things that
(34:51):
originally got me interested ininfectious diseases, because it
was that perfect example of youknow.
You have something and ourhealth is so globally
interconnected.
Now, what was that like to bethere as that was coming out?
Because I think in the news,all the articles that I've ever
seen from that time were veryfear-mongering and people were
very afraid.
So what was that like?
Speaker 6 (35:10):
Again, this one did involve community.
Speaker 5 (35:14):
Yes.
Speaker 6 (35:15):
The original part of the story was that we at CDC
knew there was something goingon in China, in southern China,
knew there was something goingon in China, in southern China,
and I think that the assumptionat the time was this was H5N1,
which goes back to 97.
We're now talking about, for us, the spring of 2003, that
(35:37):
there's something bubbling upand there were efforts made to
try and figure out what that was, to help the Chinese, which
weren't working terribly wellRight now.
This week, who has announcedthat there's a new set of
pandemic preparednessregulations that are finally, I
(35:57):
guess, finalized, that will bepresented to the World Health
Assembly, and part of this is tomake sure that if there's
something bubbling up that haspandemic or real epidemic
potential, that you report it tocentral authorities so that
international efforts to keep itlocalized or from becoming a
(36:18):
pandemic can occur.
And what happened in 2003 wasthat again, the notion that
there was something happening insouthern China was already
apparent.
We made an attempt to help insome way.
So somebody from the flu branchat CDC was actually sent to
China and I don't think I'mgoing to offend China at the
(36:41):
moment, but he was stonewalled.
He went and sat and essentiallywas offered no ability to talk
to anybody or review any data.
And shortly after that,something was starting in Hong
Kong or actually in Vietnam wasthe story, but it emanated from
(37:29):
a physician from Guangdongprovince having traveled to Hong
Kong for his daughter's weddingand staying up in a hospital
that then began to infect otherpatients and that was reported
by a WHO epidemiologist workingthere.
The epidemiologist himselfbecame infected.
He then traveled to Bangkok andwe obtained because we had some
HIV folks present in Thailandspecimens from him that were
sent to Atlanta, and those werethe specimens that I believe
(37:54):
were the actual earliestdetermination of the etiology of
this as being coronaviruses,interesting Coronavirus.
Speaker 4 (38:03):
Yeah, yeah, tom, you brought up the pandemic
agreement.
Right, that's finally, afterthree years, been finalized.
But do you think countries willstick to that agreement and
will Well after SARS?
Speaker 6 (38:14):
you have to realize that they strengthen the world
health regulations and part ofthat was to strengthen reporting
.
But in this instance and partof that was to strengthen
reporting, but in this instanceonce again, things didn't happen
the way they were.
I would say first of all thatSARS was bad, but once it was
discovered what it was, therewas follow-up and the natural
(38:39):
sort of reservoir and probablythe means of that becoming a
human transmitted disease waspretty well worked out.
If everybody wants to recallthe circumstances, I would say,
once the virus got to Wuhan atleast as far as I can tell, the
Wuhan Institute of Virology,whose name is MUD right now,
(39:03):
probably unjustifiably actuallycontacted people from the
outside and revealed thesequence of the virus and that
it was another virus.
Part of, unfortunately, thepolitical environment was that
the Chinese Communist Partyclamped down on the
(39:23):
dissemination of information andhave also suppressed other
investigations, including byinternational bodies such as WHO
, and that's the part thatsticks in everybody's craw.
Speaker 5 (39:38):
So if I can ask, because you've been present for
many outbreaks, you've helpedwork on them, you've really
contributed and helped keeppeople safe from a public health
perspective, to you, what doyou think makes or breaks an
effective outbreak response,whether that's hantaviruses,
whether that's SARS?
What does that look like?
Speaker 6 (39:56):
Figuring out what it is early and then figuring out
whether there arecountermeasures or social things
that can be done to diminishtransmission is probably the
most important.
I would use an example Ebola andthe West African outbreak.
So what happened in thatoutbreak is that outbreak
(40:16):
probably began in 2013 andessentially became disseminated
to three countries before it wasever identified as Ebola.
And holding up that same example, we had been involved at CDC
and special pathogens inparticular, in an outbreak that
(40:37):
occurred in 2000 in Uganda inGulu, and a lot of lessons were
learned from that.
Part of it was that we had apermanent presence special
pathogens in a PEPBAR CDC unitat the National Institute of
Virology in Uganda, and there'sa paper published about a number
(41:01):
of outbreaks of both Marburgand Ebola Sudan that occurred in
Uganda and that laboratorypresence had allowed the very
early identification and we hadtrained up people how to respond
early and how to isolate casesof Ebola so that they're being
(41:22):
taken care of by people who arewearing appropriate PPE, so that
there's not transmission toother people who aren't nursing
and using appropriate protectiveequipment.
And that's the key with Ebola,it's not something that
circulates in the community.
It's circulated by patientsthat become infected, have high
(41:44):
loads of virus and people thatare intimately exposing
themselves to them, then get it,and that chain goes on.
Speaker 4 (41:51):
Yeah, it's a caretaker's disease, like Paul
Farmer always says.
Yeah, all right.
Speaker 5 (41:57):
Thank you so much.
This was brilliant.
I've learned so much.
Again, we cannot thank youenough for taking the time to
come speak with us.
It's really rare and excitingto get such a well-versed expert
on the podcast.
So thank you for taking thetime, Dr Kysak Really appreciate
it.
Speaker 6 (42:10):
You're welcome, my pleasure, thank you.
Thank you.
Speaker 5 (42:13):
All right, and thanks for joining us for this episode
of Infectious Science.
As always, let us know what youwant to hear, and thanks for
listening.
Speaker 3 (42:19):
Thanks for Infectious Science podcast.
Be sure to hit subscribe andvisit infectiousscienceorg to
join the conversation, accessthe show notes and to sign up
for our newsletter and receiveour free materials.
Speaker 2 (42:30):
If you enjoyed this new episode of Infectious
Science, please leave us areview on Apple Podcasts and
Spotify, and go ahead and sharethis episode with some of your
friends.
Speaker 3 (42:38):
Also, don't hesitate to ask questions and tell us
what topics you'd like us tocover for future episodes.
To get in touch, drop a line inthe comments section or send us
a message on social media.
Speaker 2 (42:48):
So we'll see you next time for a new episode, and in
the meantime, stay happy stayhealthy, stay interested.
Speaker 3 (43:03):
Thank you.
Popular Podcasts
Bookmarked by Reese's Book Club
Welcome to Bookmarked by Reese’s Book Club — the podcast where great stories, bold women, and irresistible conversations collide! Hosted by award-winning journalist Danielle Robay, each week new episodes balance thoughtful literary insight with the fervor of buzzy book trends, pop culture and more. Bookmarked brings together celebrities, tastemakers, influencers and authors from Reese's Book Club and beyond to share stories that transcend the page. Pull up a chair. You’re not just listening — you’re part of the conversation.
On Purpose with Jay Shetty
I’m Jay Shetty host of On Purpose the worlds #1 Mental Health podcast and I’m so grateful you found us. I started this podcast 5 years ago to invite you into conversations and workshops that are designed to help make you happier, healthier and more healed. I believe that when you (yes you) feel seen, heard and understood you’re able to deal with relationship struggles, work challenges and life’s ups and downs with more ease and grace. I interview experts, celebrities, thought leaders and athletes so that we can grow our mindset, build better habits and uncover a side of them we’ve never seen before. New episodes every Monday and Friday. Your support means the world to me and I don’t take it for granted — click the follow button and leave a review to help us spread the love with On Purpose. I can’t wait for you to listen to your first or 500th episode!
Dateline NBC
Current and classic episodes, featuring compelling true-crime mysteries, powerful documentaries and in-depth investigations. Follow now to get the latest episodes of Dateline NBC completely free, or subscribe to Dateline Premium for ad-free listening and exclusive bonus content: DatelinePremium.com