>> We spend a great deal of time
looking at the impact of climate
change and how it is
changing our weather and
environment.
That can have an impact on how
pathogens and disease could
spread as well.
Our science correspondent has
the story.
>> Dawn in the high Sierra.
50 miles northwest of Reno at
the clover valley ranch.
>> Member to check every trap.
Walk the line.
>> The hunt is on once again.
>> Make sure you take the boxes.
Open, closed or empty.
>> For clues linking a changing
climate and the worsening spread
of disease.
That is ranch owner Brian, a
veterinarian and for all edges
to end director of the one
healthy institute laboratory at
the university of California
Davis.
Overnight 47 took the peanut
butter oats and bacon bait.
Now it is time to retrieve the
traps.
>> I believe that is the most we
have ever captured here.
>> And gather some data.
For three years now he and his
students have been
systematically trapping deer
mice that live here.
The rodents are the primary
reservoir for this pathogen.
>> It does not carry any harm to
the rodent.
It then they shed the virus in
urine and feces.
>> When a human gets junta
virus, is that serious?
>> It cans be -- it can be very
serious.
50% could be fatal.
It is a relatively rare but high
consequence disease.
>> It is a so-called zoonotic
disease meaning it is spread by
pathogens that spillover from
one species to another.
This is the primary cause of
pandemics throughout human
history.
Human encroachment and global
travel hastened these spillover
events.
It appears the climate crisis is
making matters even worse.
>> As animals get more stressed
they are more likely to shed a
particular virus or pathogen.
There is also the impact on the
animals themselves so where do
they live?
As the environments change the
animals will move.
Those changes occur very
gradually over millennia.
Out we are looking at dramatic
fast-paced changes on the
timescale of hundreds of years
if not faster.
>> In September of 2021 he
learned how fast.
To the fire come through here?
>> It did.
You are walking on burned area
here.
>> It was the Dixie mega
amplified by a historic drought
linked to climate change.
It burned nearly a million acres
over three months.
You had been working in the spot
prior to the fire.
>> Exactly in the spot prior to
the fire.
We had two seasons of sampling
data before the fire.
>> He expected it would take
years, even decades to connect
the dots but in his blackened
field he saw opportunity.
>> We thought this would be a
great time to continue the
sampling and see how to the road
and populations respond to
putting much a complete
destruction of their habitat.
>> They are now finding the
virus in 8% of mice they are
tracking.
In the unburned control site it
is 4%.
He says the mice are fighting to
establish turf.
>> The primary method of
transmitting the virus among
rodents is when they fight and
bite each other.
They could be transmitting the
virus at a heightened rate
compared to a control site that
was not burned.
>> That means more transmission
potentially.
>> Potentially.
>> Climate change worsens a
drought that triggers a mega
fire which wipes out a habitat
causing a rodent rumble.
A virus super-spreader.
A nuanced link to be sure but
not new.
The historical evidence linking
the climate to zoonotic disease
is growing.
Camilla is a professor at the
university of Hawaii at mandala.
He led a team that poured
through the less than 17,000
scientific studies dating back
to the end of the Roman empire.
>> 58% of the pathogens that had
impacted humidity anywhere in
the world are already affected
by climatic changes.
Theirs are the ones we already
know.
The scary things are the ones we
do not know about because the
ones we know of we know we can
cope with them.
You cannot imagine the surprise
we make it when we start
unleashing these pathogens that
could be more damaging to us.
>> At Georgetown university
global change biologist Collin
Carlsen is working on a way to
take the surprise out of this.
What are we looking at here?
>> We are looking at the
pathogen harmonize surveillance
system.
>> He is trying to meld existing
climate and disease data in a
way that allows epidemiologists
to see the big picture.
>> Let's go to Berlin.
Each of these points is
somewhere they have tested a fox
for distemper virus.
What if we knew this much about
viruses everywhere in the world?
What if we knew this about the
diseases we were worried about
jumping into humans?
We could literally know within a
city where spillover risk is the
highest.
>> He is building an open source
tool to forecast an help break
sooner -- an outbreak sooner.
He sees the ability to predict
disease as well as the weather.
>> We need to know the dynamics
of these viruses when we are not
watching them.
>> Can technology make it easier
for public health professionals
to monitor disease in wild
animal populations?
Epidemiologist Christine Johnson
is also a professional at the uc
Davis one health institute.
She is testing new ways to
monitor one of the most prolific
spreaders of zoonotic disease,
bats.
>> Did you get that stream?
>> We did.
>> She and her team are testing
thermal cameras as well as audio
devices able to record what
bat echolocation sounds
like.
They hope to employ the
technology to make it safer.
>> We are able to see them much
more clearly with thermal
cameras.
The techniques we are developing
could be used to do that
remotely.
>> She has collaborating with
the engineering department
seeking ways to monitor and test
bat populations remotely.
>> That is what we are seeking
is with innovative technology we
are using to try to bring much
more feasibility to wildlife
surveillance.
>> There are more and more
zoonotic diseases coming or the
climate crisis makes it
unavoidable.
A greater investment to protect
public health with some
21st-century tools along with
the risky laborious fieldwork
might be the only way to stop a
spillover from boiling over
shutting down the world once
again.
For the pbs newshour, I'm miles
o'brien near portola,
California.