00:13The story that I'm going
to tell you today,
00:15for me, began back in 2006.
00:17That was when I first heard
about an outbreak of mysterious illness
00:21that was happening in the Amazon
rainforest of Peru.
00:24The people that were getting sick
from this illness,
00:27they had horrifying symptoms, nightmarish.
00:29They had unbelievable headaches,
00:31they couldn't eat or drink.
00:33Some of them were even hallucinating --
00:35confused and aggressive.
00:36The most tragic part of all
00:39was that many of the victims
were children.
00:41And of all of those that got sick,
00:46It turned out that what was killing
people was a virus,
00:49but it wasn't Ebola, it wasn't Zika,
00:51it wasn't even some new virus
never before seen by science.
00:55These people were dying
of an ancient killer,
00:57one that we've known about for centuries.
01:00They were dying of rabies.
01:02And what all of them had in common
was that as they slept,
01:06they'd all been bitten by the only mammal
that lives exclusively on a diet of blood:
01:13These sorts of outbreaks
that jump from bats into people,
01:16they've become more and more common
in the last couple of decades.
01:19In 2003, it was SARS.
01:20It showed up in Chinese animal markets
and spread globally.
01:24That virus, like the one from Peru,
was eventually traced back to bats,
01:28which have probably harbored it,
undetected, for centuries.
01:32Then, 10 years later, we see Ebola
showing up in West Africa,
01:36and that surprised just about everybody
01:38because, according
to the science at the time,
01:40Ebola wasn't really supposed
to be in West Africa.
01:44That ended up causing the largest
and most widespread Ebola outbreak
01:49So there's a disturbing trend here, right?
01:52Deadly viruses are appearing in places
where we can't really expect them,
01:56and as a global health community,
01:57we're caught on our heels.
01:59We're constantly chasing
after the next viral emergency
02:02in this perpetual cycle,
02:04always trying to extinguish epidemics
after they've already started.
02:08So with new diseases appearing every year,
02:11now is really the time
02:13that we need to start thinking
about what we can do about it.
02:15If we just wait for the next
Ebola to happen,
02:18we might not be so lucky next time.
02:20We might face a different virus,
02:22one that's more deadly,
02:23one that spreads better among people,
02:26or maybe one that just completely
outwits our vaccines,
02:29leaving us defenseless.
02:31So can we anticipate pandemics?
02:36Those are really hard questions to answer,
02:39and the reason is that the pandemics --
02:42the ones that spread globally,
02:44the ones that we really
want to anticipate --
02:46they're actually really rare events.
02:48And for us as a species
that is a good thing --
02:50that's why we're all here.
02:53But from a scientific standpoint,
it's a little bit of a problem.
02:58That's because if something
happens just once or twice,
03:01that's really not enough
to find any patterns.
03:03Patterns that could tell us when
or where the next pandemic might strike.
03:10Well, I think one of the solutions
we may have is to study some viruses
03:14that routinely jump from wild
animals into people,
03:18or into our pets, or our livestock,
03:21even if they're not the same viruses
03:23that we think are going
to cause pandemics.
03:26If we can use
those everyday killer viruses
03:28to work out some of the patterns
03:30of what drives that initial, crucial jump
from one species to the next,
03:34and, potentially, how we might stop it,
03:36then we're going to end up better prepared
03:38for those viruses that jump
between species more rarely
03:41but pose a greater threat of pandemics.
03:44Now, rabies, as terrible as it is,
03:47turns out to be a pretty nice
virus in this case.
03:52You see, rabies is a scary, deadly virus.
03:55It has 100 percent fatality.
03:57That means if you get infected with rabies
and you don't get treated early,
04:01there's nothing that can be done.
04:06And rabies is not just
a problem of the past either.
04:10Even today, rabies still kills
50 to 60,000 people every year.
04:16Just put that number in some perspective.
04:19Imagine the whole West African
Ebola outbreak --
04:21about two-and-a-half years;
04:23you condense all the people
that died in that outbreak
04:26into just a single year.
04:28But then, you multiply it by four,
04:30and that's what happens
with rabies every single year.
04:35So what sets rabies apart
from a virus like Ebola
04:40is that when people get it,
04:42they tend not to spread it onward.
04:44That means that every single time
a person gets rabies,
04:48it's because they were bitten
by a rabid animal,
04:51and usually, that's a dog or a bat.
04:53But it also means that those jumps
between species,
04:56which are so important to understand,
but so rare for most viruses,
05:00for rabies, they're actually
happening by the thousands.
05:04So in a way, rabies
is almost like the fruit fly
05:08or the lab mouse of deadly viruses.
05:11This is a virus that we can use
and study to find patterns
05:15and potentially test out new solutions.
05:17And so, when I first heard
about that outbreak of rabies
05:20in the Peruvian Amazon,
05:22it struck me as something
potentially powerful
05:24because this was a virus that was jumping
from bats into other animals
05:27often enough that we might
be able to anticipate it ...
05:33So as a first-year graduate student
05:35with a vague memory
of my high school Spanish class,
05:38I jumped onto a plane
and flew off to Peru,
05:41looking for vampire bats.
05:42And the first couple of years
of this project were really tough.
05:48I had no shortage of ambitious plans
to rid Latin America of rabies,
05:52but at the same time,
05:53there seemed to be an equally endless
supply of mudslides and flat tires,
05:57power outages, stomach bugs
all stopping me.
06:01But that was kind of par for the course,
06:03working in South America,
06:04and to me, it was part of the adventure.
06:08But what kept me going
06:10was the knowledge that for the first time,
06:12the work that I was doing
might actually have some real impact
06:15on people's lives in the short term.
06:17And that struck me the most
06:18when we actually went out to the Amazon
06:21and were trying to catch vampire bats.
06:23You see, all we had to do was show up
at a village and ask around.
06:27"Who's been getting bitten
by a bat lately?"
06:29And people raised their hands,
06:31because in these communities,
06:34getting bitten by a bat
is an everyday occurrence,
06:38And so all we had to do
was go to the right house,
06:43and show up at night,
06:44and wait until the bats tried
to fly in and feed on human blood.
06:49So to me, seeing a child with a bite wound
on his head or blood stains on his sheets,
06:54that was more than enough motivation
06:56to get past whatever logistical
or physical headache
06:59I happened to be feeling on that day.
07:02Since we were working
all night long, though,
07:05I had plenty of time to think about
how I might actually solve this problem,
07:08and it stood out to me
that there were two burning questions.
07:11The first was that we know
that people are bitten all the time,
07:15but rabies outbreaks
aren't happening all the time --
07:18every couple of years,
maybe even every decade,
07:20you get a rabies outbreak.
07:22So if we could somehow anticipate
when and where the next outbreak would be,
07:26that would be a real opportunity,
07:27meaning we could vaccinate
people ahead of time,
07:30before anybody starts dying.
07:32But the other side of that coin
07:34is that vaccination
is really just a Band-Aid.
07:38It's kind of a strategy of damage control.
07:40Of course it's lifesaving and important
and we have to do it,
07:43but at the end of the day,
07:44no matter how many cows,
how many people we vaccinate,
07:47we're still going to have exactly the same
amount of rabies up there in the bats.
07:51The actual risk of getting bitten
hasn't changed at all.
07:53So my second question was this:
07:55Could we somehow
cut the virus off at its source?
07:59If we could somehow reduce the amount
of rabies in the bats themselves,
08:02then that would be a real game changer.
08:04We'd been talking about shifting
08:06from a strategy of damage control
to one based on prevention.
08:10So, how do we begin to do that?
08:13Well, the first thing
we needed to understand
08:15was how this virus actually works
in its natural host --
08:19And that is a tall order
for any infectious disease,
08:21particularly one in a reclusive
species like bats,
08:25but we had to start somewhere.
08:28So the way we started
was looking at some historical data.
08:31When and where had these outbreaks
happened in the past?
08:35And it became clear
that rabies was a virus
08:37that just had to be on the move.
08:39It couldn't sit still.
08:41The virus might circulate in one area
for a year, maybe two,
08:44but unless it found a new group of bats
to infect somewhere else,
08:47it was pretty much bound to go extinct.
08:50So with that, we solved one key part
of the rabies transmission challenge.
08:55We knew we were dealing
with a virus on the move,
08:58but we still couldn't say
where it was going.
09:01Essentially, what I wanted was
more of a Google Maps-style prediction,
09:05which is, "What's
the destination of the virus?
09:07What's the route it's going
to take to get there?
09:10How fast will it move?"
09:13To do that, I turned
to the genomes of rabies.
09:17You see, rabies, like many other viruses,
has a tiny little genome,
09:21but one that evolves
really, really quickly.
09:23So quickly that by the time the virus
has moved from one point to the next,
09:28it's going to have picked up
a couple of new mutations.
09:31And so all we have to do
is kind of connect the dots
09:33across an evolutionary tree,
09:35and that's going to tell us
where the virus has been in the past
09:38and how it spread across the landscape.
09:40So, I went out and I collected cow brains,
09:44because that's where
you get rabies viruses.
09:47And from genome sequences that we got
from the viruses in those cow brains,
09:52I was able to work out
09:53that this is a virus that spreads
between 10 and 20 miles each year.
09:57OK, so that means we do now have
the speed limit of the virus,
10:01but still missing that other key part
of where is it going in the first place.
10:06For that, I needed to think
a little bit more like a bat,
10:10because rabies is a virus --
10:12it doesn't move by itself,
10:13it has to be moved around by its bat host,
10:16so I needed to think about
how far to fly and how often to fly.
10:20My imagination didn't get me
all that far with this
10:23and neither did little digital trackers
that we first tried putting on bats.
10:26We just couldn't get
the information we needed.
10:29So instead, we turned
to the mating patterns of bats.
10:32We could look at certain parts
of the bat genome,
10:34and they were telling us that some
groups of bats were mating with each other
10:37and others were more isolated.
10:39And the virus was basically following
the trail laid out by the bat genomes.
10:44Yet one of those trails stood out
as being a little bit surprising --
10:50That was one that seemed to cross
straight over the Peruvian Andes,
10:53crossing from the Amazon
to the Pacific coast,
10:56and that was kind of hard to believe,
11:01because the Andes are really tall --
about 22,000 feet,
11:04and that's way too high
for a vampire to fly.
11:10when we looked more closely,
11:11we saw, in the northern part of Peru,
11:13a network of valley systems
that was not quite too tall
11:17for the bats on either side
to be mating with each other.
11:20And we looked a little bit more closely --
11:22sure enough, there's rabies
spreading through those valleys,
11:24just about 10 miles each year.
11:26Basically, exactly as our evolutionary
models had predicated it would be.
11:30What I didn't tell you
11:31is that that's actually
kind of an important thing
11:34because rabies had never been seen before
on the western slopes of the Andes,
11:37or on the whole Pacific coast
of South America,
11:40so we were actually witnessing,
in real time, a historical first invasion
11:44into a pretty big part of South America,
11:47which raises the key question:
11:49"What are we going to do about that?"
11:51Well, the obvious short-term
thing we can do is tell people:
11:55you need to vaccinate yourselves,
vaccinate your animals;
11:59But in the longer term,
12:00it would be even more powerful
if we could use that new information
12:04to stop the virus
from arriving altogether.
12:07Of course, we can't just tell bats,
"Don't fly today,"
12:11but maybe we could stop the virus
from hitching a ride along with the bat.
12:16And that brings us to the key lesson
that we have learned
12:19from rabies-management programs
all around the world,
12:22whether it's dogs, foxes,
skunks, raccoons,
12:26North America, Africa, Europe.
12:29It's that vaccinating the animal source
is the only thing that stops rabies.
12:34So, can we vaccinate bats?
12:38You hear about vaccinating dogs
and cats all the time,
12:41but you don't hear too much
about vaccinating bats.
12:44It might sound like a crazy question,
12:46but the good news is that we actually
already have edible rabies vaccines
12:51that are specially designed for bats.
12:54And what's even better
12:55is that these vaccines
can actually spread from bat to bat.
13:00All you have to do is smear it on one
13:02and let the bats' habit
of grooming each other
13:05take care of the rest of the work for you.
13:07So that means, at the very least,
13:09we don't have to be out there vaccinating
millions of bats one by one
13:12with tiny little syringes.
13:15But just because we have that tool
doesn't mean we know how to use it.
13:19Now we have a whole laundry
list of questions.
13:21How many bats do we need to vaccinate?
13:23What time of the year
do we need to be vaccinating?
13:26How many times a year
do we need to be vaccinating?
13:30All of these are questions
that are really fundamental
13:32to rolling out any sort
of vaccination campaign,
13:34but they're questions
that we can't answer in the laboratory.
13:37So instead, we're taking
a slightly more colorful approach.
13:41We're using real wild bats,
but fake vaccines.
13:45We use edible gels that make bat hair glow
13:48and UV powders that spread between
bats when they bump into each other,
13:51and that's letting us study
how well a real vaccine might spread
13:54in these wild colonies of bats.
13:57We're still in the earliest
phases of this work,
14:00but our results so far
are incredibly encouraging.
14:03They're suggesting that using
the vaccines that we already have,
14:06we could potentially drastically reduce
the size of rabies outbreaks.
14:10And that matters, because as you remember,
14:13rabies is a virus that always
has to be on the move,
14:16and so every time we reduce
the size of an outbreak,
14:19we're also reducing the chance
14:20that the virus makes it
onto the next colony.
14:23We're breaking a link
in the chain of transmission.
14:26And so every time we do that,
14:27we're bringing the virus
one step closer to extinction.
14:30And so the thought, for me,
of a world in the not-too-distant future
14:35where we're actually talking
about getting rid of rabies altogether,
14:38that is incredibly
encouraging and exciting.
14:41So let me return to the original question.
14:43Can we prevent pandemics?
14:46Well, there is no silver-bullet
solution to this problem,
14:50but my experiences with rabies
have left me pretty optimistic about it.
14:54I think we're not too far from a future
14:56where we're going to have genomics
to forecast outbreaks
14:59and we're going to have clever
new technologies,
15:02like edible, self-spreading vaccines,
15:05that can get rid of these
viruses at their source
15:07before they have a chance
to jump into people.
15:10So when it comes to fighting pandemics,
15:13the holy grail is just to get
one step ahead.
15:17I think one of the ways
that we can do that
15:19is using some of the problems
that we already have now,
15:23sort of the way an astronaut
might use a flight simulator,
15:26figuring out what works and what doesn't,
15:28and building up our tool set
15:29so that when the stakes are high,
15:31we're not flying blind.
