What vaccinating vampire bats can teach us about pandemics
-
0:01 - 0:03The story that I'm going
to tell you today, -
0:03 - 0:05for me, began back in 2006.
-
0:05 - 0:09That was when I first heard
about an outbreak of mysterious illness -
0:09 - 0:12that was happening in the Amazon
rainforest of Peru. -
0:13 - 0:15The people that were getting sick
from this illness, -
0:15 - 0:18they had horrifying symptoms, nightmarish.
-
0:18 - 0:19They had unbelievable headaches,
-
0:20 - 0:21they couldn't eat or drink.
-
0:21 - 0:23Some of them were even hallucinating --
-
0:23 - 0:24confused and aggressive.
-
0:25 - 0:27The most tragic part of all
-
0:27 - 0:29was that many of the victims
were children. -
0:29 - 0:32And of all of those that got sick,
-
0:32 - 0:33none survived.
-
0:35 - 0:37It turned out that what was killing
people was a virus, -
0:37 - 0:40but it wasn't Ebola, it wasn't Zika,
-
0:40 - 0:43it wasn't even some new virus
never before seen by science. -
0:44 - 0:46These people were dying
of an ancient killer, -
0:46 - 0:48one that we've known about for centuries.
-
0:48 - 0:50They were dying of rabies.
-
0:51 - 0:54And what all of them had in common
was that as they slept, -
0:54 - 0:59they'd all been bitten by the only mammal
that lives exclusively on a diet of blood: -
0:59 - 1:00the vampire bat.
-
1:01 - 1:04These sorts of outbreaks
that jump from bats into people, -
1:04 - 1:07they've become more and more common
in the last couple of decades. -
1:07 - 1:09In 2003, it was SARS.
-
1:09 - 1:12It showed up in Chinese animal markets
and spread globally. -
1:12 - 1:17That virus, like the one from Peru,
was eventually traced back to bats, -
1:17 - 1:19which have probably harbored it,
undetected, for centuries. -
1:20 - 1:25Then, 10 years later, we see Ebola
showing up in West Africa, -
1:25 - 1:27and that surprised just about everybody
-
1:27 - 1:29because, according
to the science at the time, -
1:29 - 1:31Ebola wasn't really supposed
to be in West Africa. -
1:32 - 1:35That ended up causing the largest
and most widespread Ebola outbreak -
1:35 - 1:37in history.
-
1:38 - 1:40So there's a disturbing trend here, right?
-
1:40 - 1:44Deadly viruses are appearing in places
where we can't really expect them, -
1:44 - 1:46and as a global health community,
-
1:46 - 1:47we're caught on our heels.
-
1:47 - 1:50We're constantly chasing
after the next viral emergency -
1:50 - 1:52in this perpetual cycle,
-
1:52 - 1:56always trying to extinguish epidemics
after they've already started. -
1:56 - 1:59So with new diseases appearing every year,
-
1:59 - 2:01now is really the time
-
2:01 - 2:04that we need to start thinking
about what we can do about it. -
2:04 - 2:06If we just wait for the next
Ebola to happen, -
2:06 - 2:08we might not be so lucky next time.
-
2:08 - 2:10We might face a different virus,
-
2:10 - 2:11one that's more deadly,
-
2:12 - 2:14one that spreads better among people,
-
2:14 - 2:17or maybe one that just completely
outwits our vaccines, -
2:17 - 2:19leaving us defenseless.
-
2:20 - 2:23So can we anticipate pandemics?
-
2:23 - 2:24Can we stop them?
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2:24 - 2:28Those are really hard questions to answer,
-
2:28 - 2:30and the reason is that the pandemics --
-
2:30 - 2:32the ones that spread globally,
-
2:32 - 2:34the ones that we really
want to anticipate -- -
2:34 - 2:36they're actually really rare events.
-
2:36 - 2:39And for us as a species
that is a good thing -- -
2:39 - 2:40that's why we're all here.
-
2:41 - 2:46But from a scientific standpoint,
it's a little bit of a problem. -
2:47 - 2:49That's because if something
happens just once or twice, -
2:49 - 2:52that's really not enough
to find any patterns. -
2:52 - 2:55Patterns that could tell us when
or where the next pandemic might strike. -
2:56 - 2:57So what do we do?
-
2:58 - 3:03Well, I think one of the solutions
we may have is to study some viruses -
3:03 - 3:06that routinely jump from wild
animals into people, -
3:07 - 3:09or into our pets, or our livestock,
-
3:10 - 3:12even if they're not the same viruses
-
3:12 - 3:14that we think are going
to cause pandemics. -
3:14 - 3:17If we can use
those everyday killer viruses -
3:17 - 3:18to work out some of the patterns
-
3:19 - 3:22of what drives that initial, crucial jump
from one species to the next, -
3:22 - 3:25and, potentially, how we might stop it,
-
3:25 - 3:27then we're going to end up better prepared
-
3:27 - 3:30for those viruses that jump
between species more rarely -
3:30 - 3:32but pose a greater threat of pandemics.
-
3:32 - 3:35Now, rabies, as terrible as it is,
-
3:35 - 3:39turns out to be a pretty nice
virus in this case. -
3:40 - 3:43You see, rabies is a scary, deadly virus.
-
3:44 - 3:45It has 100 percent fatality.
-
3:45 - 3:49That means if you get infected with rabies
and you don't get treated early, -
3:49 - 3:51there's nothing that can be done.
-
3:51 - 3:52There is no cure.
-
3:52 - 3:53You will die.
-
3:55 - 3:58And rabies is not just
a problem of the past either. -
3:59 - 4:03Even today, rabies still kills
50 to 60,000 people every year. -
4:04 - 4:07Just put that number in some perspective.
-
4:07 - 4:10Imagine the whole West African
Ebola outbreak -- -
4:10 - 4:12about two-and-a-half years;
-
4:12 - 4:14you condense all the people
that died in that outbreak -
4:14 - 4:15into just a single year.
-
4:15 - 4:17That's pretty bad.
-
4:17 - 4:19But then, you multiply it by four,
-
4:19 - 4:21and that's what happens
with rabies every single year. -
4:24 - 4:28So what sets rabies apart
from a virus like Ebola -
4:28 - 4:30is that when people get it,
-
4:30 - 4:32they tend not to spread it onward.
-
4:33 - 4:37That means that every single time
a person gets rabies, -
4:37 - 4:39it's because they were bitten
by a rabid animal, -
4:39 - 4:41and usually, that's a dog or a bat.
-
4:41 - 4:45But it also means that those jumps
between species, -
4:45 - 4:49which are so important to understand,
but so rare for most viruses, -
4:49 - 4:52for rabies, they're actually
happening by the thousands. -
4:53 - 4:56So in a way, rabies
is almost like the fruit fly -
4:56 - 4:58or the lab mouse of deadly viruses.
-
4:59 - 5:03This is a virus that we can use
and study to find patterns -
5:03 - 5:05and potentially test out new solutions.
-
5:06 - 5:09And so, when I first heard
about that outbreak of rabies -
5:09 - 5:10in the Peruvian Amazon,
-
5:10 - 5:12it struck me as something
potentially powerful -
5:12 - 5:16because this was a virus that was jumping
from bats into other animals -
5:16 - 5:19often enough that we might
be able to anticipate it ... -
5:19 - 5:20Maybe even stop it.
-
5:21 - 5:24So as a first-year graduate student
-
5:24 - 5:26with a vague memory
of my high school Spanish class, -
5:26 - 5:29I jumped onto a plane
and flew off to Peru, -
5:29 - 5:31looking for vampire bats.
-
5:31 - 5:35And the first couple of years
of this project were really tough. -
5:36 - 5:40I had no shortage of ambitious plans
to rid Latin America of rabies, -
5:40 - 5:42but at the same time,
-
5:42 - 5:45there seemed to be an equally endless
supply of mudslides and flat tires, -
5:45 - 5:49power outages, stomach bugs
all stopping me. -
5:49 - 5:51But that was kind of par for the course,
-
5:52 - 5:53working in South America,
-
5:53 - 5:55and to me, it was part of the adventure.
-
5:56 - 5:59But what kept me going
-
5:59 - 6:01was the knowledge that for the first time,
-
6:01 - 6:04the work that I was doing
might actually have some real impact -
6:04 - 6:05on people's lives in the short term.
-
6:05 - 6:07And that struck me the most
-
6:07 - 6:09when we actually went out to the Amazon
-
6:09 - 6:11and were trying to catch vampire bats.
-
6:12 - 6:15You see, all we had to do was show up
at a village and ask around. -
6:15 - 6:18"Who's been getting bitten
by a bat lately?" -
6:18 - 6:20And people raised their hands,
-
6:20 - 6:22because in these communities,
-
6:22 - 6:25getting bitten by a bat
is an everyday occurrence, -
6:25 - 6:26happens every day.
-
6:27 - 6:30And so all we had to do
was go to the right house, -
6:30 - 6:31open up a net
-
6:31 - 6:32and show up at night,
-
6:32 - 6:36and wait until the bats tried
to fly in and feed on human blood. -
6:37 - 6:43So to me, seeing a child with a bite wound
on his head or blood stains on his sheets, -
6:43 - 6:45that was more than enough motivation
-
6:45 - 6:47to get past whatever logistical
or physical headache -
6:47 - 6:49I happened to be feeling on that day.
-
6:51 - 6:53Since we were working
all night long, though, -
6:53 - 6:57I had plenty of time to think about
how I might actually solve this problem, -
6:57 - 7:00and it stood out to me
that there were two burning questions. -
7:00 - 7:04The first was that we know
that people are bitten all the time, -
7:04 - 7:06but rabies outbreaks
aren't happening all the time -- -
7:06 - 7:09every couple of years,
maybe even every decade, -
7:09 - 7:10you get a rabies outbreak.
-
7:10 - 7:14So if we could somehow anticipate
when and where the next outbreak would be, -
7:14 - 7:16that would be a real opportunity,
-
7:16 - 7:18meaning we could vaccinate
people ahead of time, -
7:18 - 7:20before anybody starts dying.
-
7:20 - 7:23But the other side of that coin
-
7:23 - 7:26is that vaccination
is really just a Band-Aid. -
7:26 - 7:28It's kind of a strategy of damage control.
-
7:28 - 7:31Of course it's lifesaving and important
and we have to do it, -
7:31 - 7:33but at the end of the day,
-
7:33 - 7:35no matter how many cows,
how many people we vaccinate, -
7:35 - 7:39we're still going to have exactly the same
amount of rabies up there in the bats. -
7:39 - 7:42The actual risk of getting bitten
hasn't changed at all. -
7:42 - 7:43So my second question was this:
-
7:43 - 7:47Could we somehow
cut the virus off at its source? -
7:47 - 7:51If we could somehow reduce the amount
of rabies in the bats themselves, -
7:51 - 7:53then that would be a real game changer.
-
7:53 - 7:54We'd been talking about shifting
-
7:54 - 7:57from a strategy of damage control
to one based on prevention. -
7:59 - 8:01So, how do we begin to do that?
-
8:01 - 8:03Well, the first thing
we needed to understand -
8:04 - 8:06was how this virus actually works
in its natural host -- -
8:06 - 8:07in the bats.
-
8:07 - 8:10And that is a tall order
for any infectious disease, -
8:10 - 8:14particularly one in a reclusive
species like bats, -
8:14 - 8:15but we had to start somewhere.
-
8:16 - 8:19So the way we started
was looking at some historical data. -
8:20 - 8:22When and where had these outbreaks
happened in the past? -
8:23 - 8:26And it became clear
that rabies was a virus -
8:26 - 8:27that just had to be on the move.
-
8:28 - 8:29It couldn't sit still.
-
8:29 - 8:32The virus might circulate in one area
for a year, maybe two, -
8:32 - 8:35but unless it found a new group of bats
to infect somewhere else, -
8:35 - 8:37it was pretty much bound to go extinct.
-
8:38 - 8:43So with that, we solved one key part
of the rabies transmission challenge. -
8:44 - 8:46We knew we were dealing
with a virus on the move, -
8:46 - 8:48but we still couldn't say
where it was going. -
8:49 - 8:53Essentially, what I wanted was
more of a Google Maps-style prediction, -
8:53 - 8:56which is, "What's
the destination of the virus? -
8:56 - 8:58What's the route it's going
to take to get there? -
8:58 - 9:00How fast will it move?"
-
9:01 - 9:05To do that, I turned
to the genomes of rabies. -
9:05 - 9:09You see, rabies, like many other viruses,
has a tiny little genome, -
9:09 - 9:11but one that evolves
really, really quickly. -
9:12 - 9:16So quickly that by the time the virus
has moved from one point to the next, -
9:16 - 9:19it's going to have picked up
a couple of new mutations. -
9:19 - 9:22And so all we have to do
is kind of connect the dots -
9:22 - 9:24across an evolutionary tree,
-
9:24 - 9:27and that's going to tell us
where the virus has been in the past -
9:27 - 9:29and how it spread across the landscape.
-
9:29 - 9:32So, I went out and I collected cow brains,
-
9:32 - 9:34because that's where
you get rabies viruses. -
9:35 - 9:40And from genome sequences that we got
from the viruses in those cow brains, -
9:40 - 9:41I was able to work out
-
9:41 - 9:44that this is a virus that spreads
between 10 and 20 miles each year. -
9:45 - 9:49OK, so that means we do now have
the speed limit of the virus, -
9:49 - 9:53but still missing that other key part
of where is it going in the first place. -
9:54 - 9:59For that, I needed to think
a little bit more like a bat, -
9:59 - 10:00because rabies is a virus --
-
10:00 - 10:01it doesn't move by itself,
-
10:01 - 10:04it has to be moved around by its bat host,
-
10:04 - 10:08so I needed to think about
how far to fly and how often to fly. -
10:08 - 10:11My imagination didn't get me
all that far with this -
10:11 - 10:15and neither did little digital trackers
that we first tried putting on bats. -
10:15 - 10:17We just couldn't get
the information we needed. -
10:17 - 10:20So instead, we turned
to the mating patterns of bats. -
10:20 - 10:22We could look at certain parts
of the bat genome, -
10:22 - 10:26and they were telling us that some
groups of bats were mating with each other -
10:26 - 10:27and others were more isolated.
-
10:27 - 10:32And the virus was basically following
the trail laid out by the bat genomes. -
10:33 - 10:36Yet one of those trails stood out
as being a little bit surprising -- -
10:36 - 10:37hard to believe.
-
10:38 - 10:42That was one that seemed to cross
straight over the Peruvian Andes, -
10:42 - 10:44crossing from the Amazon
to the Pacific coast, -
10:44 - 10:47and that was kind of hard to believe,
-
10:47 - 10:49as I said,
-
10:49 - 10:52because the Andes are really tall --
about 22,000 feet, -
10:52 - 10:55and that's way too high
for a vampire to fly. -
10:56 - 10:57Yet --
-
10:57 - 10:58(Laughter)
-
10:58 - 11:00when we looked more closely,
-
11:00 - 11:02we saw, in the northern part of Peru,
-
11:02 - 11:05a network of valley systems
that was not quite too tall -
11:05 - 11:08for the bats on either side
to be mating with each other. -
11:08 - 11:10And we looked a little bit more closely --
-
11:10 - 11:13sure enough, there's rabies
spreading through those valleys, -
11:13 - 11:15just about 10 miles each year.
-
11:15 - 11:18Basically, exactly as our evolutionary
models had predicated it would be. -
11:19 - 11:20What I didn't tell you
-
11:20 - 11:22is that that's actually
kind of an important thing -
11:22 - 11:26because rabies had never been seen before
on the western slopes of the Andes, -
11:26 - 11:29or on the whole Pacific coast
of South America, -
11:29 - 11:33so we were actually witnessing,
in real time, a historical first invasion -
11:33 - 11:36into a pretty big part of South America,
-
11:36 - 11:37which raises the key question:
-
11:37 - 11:39"What are we going to do about that?"
-
11:40 - 11:43Well, the obvious short-term
thing we can do is tell people: -
11:43 - 11:46you need to vaccinate yourselves,
vaccinate your animals; -
11:46 - 11:47rabies is coming.
-
11:48 - 11:49But in the longer term,
-
11:49 - 11:52it would be even more powerful
if we could use that new information -
11:52 - 11:55to stop the virus
from arriving altogether. -
11:56 - 11:59Of course, we can't just tell bats,
"Don't fly today," -
11:59 - 12:03but maybe we could stop the virus
from hitching a ride along with the bat. -
12:04 - 12:07And that brings us to the key lesson
that we have learned -
12:08 - 12:10from rabies-management programs
all around the world, -
12:10 - 12:15whether it's dogs, foxes,
skunks, raccoons, -
12:15 - 12:18North America, Africa, Europe.
-
12:18 - 12:21It's that vaccinating the animal source
is the only thing that stops rabies. -
12:22 - 12:25So, can we vaccinate bats?
-
12:27 - 12:29You hear about vaccinating dogs
and cats all the time, -
12:29 - 12:32but you don't hear too much
about vaccinating bats. -
12:33 - 12:35It might sound like a crazy question,
-
12:35 - 12:40but the good news is that we actually
already have edible rabies vaccines -
12:40 - 12:42that are specially designed for bats.
-
12:42 - 12:44And what's even better
-
12:44 - 12:48is that these vaccines
can actually spread from bat to bat. -
12:48 - 12:51All you have to do is smear it on one
-
12:51 - 12:53and let the bats' habit
of grooming each other -
12:53 - 12:55take care of the rest of the work for you.
-
12:55 - 12:57So that means, at the very least,
-
12:58 - 13:01we don't have to be out there vaccinating
millions of bats one by one -
13:01 - 13:02with tiny little syringes.
-
13:02 - 13:04(Laughter)
-
13:04 - 13:07But just because we have that tool
doesn't mean we know how to use it. -
13:07 - 13:10Now we have a whole laundry
list of questions. -
13:10 - 13:12How many bats do we need to vaccinate?
-
13:12 - 13:14What time of the year
do we need to be vaccinating? -
13:14 - 13:17How many times a year
do we need to be vaccinating? -
13:18 - 13:21All of these are questions
that are really fundamental -
13:21 - 13:23to rolling out any sort
of vaccination campaign, -
13:23 - 13:26but they're questions
that we can't answer in the laboratory. -
13:26 - 13:29So instead, we're taking
a slightly more colorful approach. -
13:29 - 13:33We're using real wild bats,
but fake vaccines. -
13:34 - 13:36We use edible gels that make bat hair glow
-
13:36 - 13:40and UV powders that spread between
bats when they bump into each other, -
13:40 - 13:43and that's letting us study
how well a real vaccine might spread -
13:43 - 13:45in these wild colonies of bats.
-
13:46 - 13:48We're still in the earliest
phases of this work, -
13:48 - 13:51but our results so far
are incredibly encouraging. -
13:51 - 13:54They're suggesting that using
the vaccines that we already have, -
13:54 - 13:58we could potentially drastically reduce
the size of rabies outbreaks. -
13:59 - 14:01And that matters, because as you remember,
-
14:01 - 14:04rabies is a virus that always
has to be on the move, -
14:04 - 14:07and so every time we reduce
the size of an outbreak, -
14:07 - 14:09we're also reducing the chance
-
14:09 - 14:11that the virus makes it
onto the next colony. -
14:11 - 14:14We're breaking a link
in the chain of transmission. -
14:14 - 14:16And so every time we do that,
-
14:16 - 14:19we're bringing the virus
one step closer to extinction. -
14:19 - 14:24And so the thought, for me,
of a world in the not-too-distant future -
14:24 - 14:27where we're actually talking
about getting rid of rabies altogether, -
14:27 - 14:29that is incredibly
encouraging and exciting. -
14:30 - 14:32So let me return to the original question.
-
14:32 - 14:33Can we prevent pandemics?
-
14:34 - 14:38Well, there is no silver-bullet
solution to this problem, -
14:38 - 14:42but my experiences with rabies
have left me pretty optimistic about it. -
14:42 - 14:44I think we're not too far from a future
-
14:44 - 14:48where we're going to have genomics
to forecast outbreaks -
14:48 - 14:50and we're going to have clever
new technologies, -
14:50 - 14:53like edible, self-spreading vaccines,
-
14:53 - 14:56that can get rid of these
viruses at their source -
14:56 - 14:58before they have a chance
to jump into people. -
14:59 - 15:01So when it comes to fighting pandemics,
-
15:01 - 15:03the holy grail is just to get
one step ahead. -
15:04 - 15:05And if you ask me,
-
15:05 - 15:07I think one of the ways
that we can do that -
15:07 - 15:10is using some of the problems
that we already have now, -
15:10 - 15:11like rabies --
-
15:11 - 15:14sort of the way an astronaut
might use a flight simulator, -
15:14 - 15:16figuring out what works and what doesn't,
-
15:16 - 15:18and building up our tool set
-
15:18 - 15:19so that when the stakes are high,
-
15:19 - 15:20we're not flying blind.
-
15:21 - 15:22Thank you.
-
15:22 - 15:26(Applause)
- Title:
- What vaccinating vampire bats can teach us about pandemics
- Speaker:
- Daniel Streicker
- Description:
-
Could we anticipate the next big disease outbreak, stopping a virus like Ebola before it ever strikes? In this talk about frontline scientific research, ecologist Daniel Streicker takes us to the Amazon rainforest in Peru where he tracks the movement of vampire bats in order to forecast and prevent rabies outbreaks. By studying these disease patterns, Streicker shows how we could learn to cut off the next pandemic at its source.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TEDTalks
- Duration:
- 15:39
Oliver Friedman edited English subtitles for What vaccinating vampire bats can teach us about pandemics | ||
Oliver Friedman approved English subtitles for What vaccinating vampire bats can teach us about pandemics | ||
Oliver Friedman edited English subtitles for What vaccinating vampire bats can teach us about pandemics | ||
Krystian Aparta accepted English subtitles for What vaccinating vampire bats can teach us about pandemics | ||
Krystian Aparta edited English subtitles for What vaccinating vampire bats can teach us about pandemics | ||
Leslie Gauthier edited English subtitles for What vaccinating vampire bats can teach us about pandemics | ||
Leslie Gauthier edited English subtitles for What vaccinating vampire bats can teach us about pandemics | ||
Leslie Gauthier edited English subtitles for What vaccinating vampire bats can teach us about pandemics |