Why we have virus outbreaks & how we can prevent them | Nathan Wolfe

314,688 views ・ 2009-03-27

TED


Please double-click on the English subtitles below to play the video.

00:18
When most people think about the beginnings
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of AIDS, they're gonna think back to the 1980s.
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And certainly, this was the decade in which we discovered AIDS
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and the virus that causes it, HIV.
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But in fact this virus crossed over into humans many decades before,
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from chimpanzees, where the virus originated, into humans who hunt these apes.
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This photo was taken before the Great Depression
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in Brazzaville, Congo.
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At this time, there were thousands of individuals,
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we think, that were infected with HIV.
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So I have a couple of really important questions for you.
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If this virus was in thousands
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of individuals at this point,
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why was it the case that it took us until 1984
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to be able to discover this virus?
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OK now, more importantly,
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had we been there in the '40s and '50s, '60s,
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had we seen this disease, had we understood
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exactly what was going on with it, how might that have changed and completely
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transformed the nature of the way this pandemic moved?
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In fact, this is not unique to HIV. The vast majority of
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viruses come from animals.
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And you can kind of think of this as a pyramid of this bubbling up of viruses
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from animals into human populations.
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But only at the very top of this pyramid do these things become completely human.
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Nevertheless, we spend the vast majority
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of our energy focused on this level of the pyramid,
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trying to tackle things that are already completely adapted to human beings,
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that are going to be very very difficult to address --
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as we've seen in the case of HIV.
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So during the last 15 years,
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I've been working to actually study the earlier interface here --
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what I've labeled "viral chatter," which was a term coined
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by my mentor Don Burke.
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This is the idea that we can study the sort of
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pinging of these viruses into human populations,
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the movement of these agents over into humans;
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and by capturing this moment,
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we might be able to move to a situation where we can catch them early.
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OK, so this is a picture, and I'm going to show you
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some pictures now from the field.
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This is a picture of a central African hunter.
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It's actually a fairly common picture.
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One of the things I want you to note from it
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is blood -- that you see a tremendous amount of blood contact.
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This was absolutely key for us. This is a
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very intimate form of connection.
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So if we're going to study viral chatter, we need to
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get to these populations who have intensive contact with wild animals.
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And so we've been studying people like this individual.
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We collect blood from them, other specimens.
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We look at the diseases, which are in the animals as well as the humans.
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And ideally, this is going to allow us to catch these things
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early on, as they're moving over into human populations.
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And the basic objective of this work is not to just
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go out once and look at these individuals,
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but to establish thousands of individuals
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in these populations that we would monitor
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continuously on a regular basis.
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When they were sick, we would collect specimens from them.
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We would actually enlist them --
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which we've done now -- to collect specimens from animals.
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We give them these little pieces of filter paper.
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When they sample from animals,
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they collect the blood on the filter paper
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and this allows us to identify yet-unknown viruses from exactly the right animals --
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the ones that are actually being hunted.
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(Video) Narrator: Deep in a remote region of Cameroon,
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two hunters stalk their prey.
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Their names are Patrice and Patee.
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They're searching for bush meat;
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forest animals they can kill to feed their families.
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Patrice and Patee set out most days to go out hunting
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in the forest around their homes.
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They have a series of traps, of snares that they've set up
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to catch wild pigs, snakes, monkeys,
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rodents -- anything they can, really.
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Patrice and Patee have been out for hours but found nothing.
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The animals are simply gone.
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We stop for a drink of water.
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Then there is a rustle in the brush.
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A group of hunters approach,
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their packs loaded with wild game.
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There's at least three viruses
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that you know about, which are in this particular monkey.
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Nathan Wolfe: This species, yeah. And there's many many more pathogens
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that are present in these animals.
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These individuals are at specific risk,
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particularly if there's blood contact, they're at risk for transmission
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and possibly infection with novel viruses.
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Narrator: As the hunters display their kills, something surprising happens.
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They show us filter paper they've used to collect the animals' blood.
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The blood will be tested for zoonotic viruses,
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part of a program Dr. Wolfe has spent years setting up.
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NW: So this is from this animal right here,
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Greater Spot-Nosed Guenon.
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Every person who has one of those filter papers has at least,
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at a minimum, been through our basic health education
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about the risks associated with these activities,
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which presumably, from our perspective,
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gives them the ability to decrease their own risk,
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and then obviously the risk to their families,
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the village, the country, and the world.
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NW: OK, before I continue, I think it's important to take just a moment
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to talk about bush meat. Bush meat is the hunting of wild game.
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OK? And you can consider all sorts of different bush meat.
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I'm going to be talking about this.
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When your children and grandchildren
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sort of pose questions to you about this period of time,
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one of the things they're gonna ask you,
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is how it was they we allowed some of our closest living relatives,
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some of the most valuable and endangered species
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on our planet, to go extinct because we
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weren't able to address some of the issues
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of poverty in these parts of the world.
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But in fact that's not the only question they're going to ask you about this.
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They're also going to ask you the question
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that when we knew that this was the way that HIV entered
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into the human population,
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and that other diseases had the potential to enter like this,
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why did we let these behaviors continue?
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Why did we not find some other solution to this?
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They're going to say, in regions of profound
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instability throughout the world,
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where you have intense poverty, where populations are growing
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and you don't have sustainable resources like this,
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this is going to lead to food insecurity.
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But they're also going to ask you probably a different question.
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It's one that I think we all need to ask ourselves,
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which is, why we thought the responsibility rested with this individual here.
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Now this is the individual -- you can see just right up over his right shoulder --
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this is the individual that hunted the monkey
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from the last picture that I showed you.
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OK, take a look at his shirt.
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You know, take a look at his face.
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Bush meat is one of the central crises,
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which is occurring in our population right now,
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in humanity, on this planet.
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But it can't be the fault of somebody like this.
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OK? And solving it cannot be his responsibility alone.
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There's no easy solutions,
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but what I'm saying to you is that we neglect this problem
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at our own peril.
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So, in 1998, along with my mentors
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Don Burke and Colonel Mpoudi-Ngole,
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we went to actually start this work
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in Central Africa, to work with hunters
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in this part of the world.
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And my job -- at that time I was a post-doctoral fellow,
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and I was really tasked with setting this up.
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So I said to myself, "OK, great --
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we're gonna collect all kinds of specimens. We're gonna go to all these
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different locations. It's going to be wonderful."
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You know, I looked at the map; I picked out 17 sites;
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I figured, no problem.
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(Laughter)
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Needless to say, I was drastically wrong.
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This is challenging work to do.
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Fortunately, I had and continue to have
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an absolutely wonderful team of colleagues and collaborators in my own team,
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and that's the only way that this work can really occur.
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We have a whole range of challenges about this work.
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One of them is just obtaining trust
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from individuals that we work with in the field.
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The person you see on the right hand side is Paul DeLong-Minutu.
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He's one of the best communicators that I've really ever dealt with.
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When I arrived I didn't speak a word of French,
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and I still seemed to understand what it was he was saying.
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Paul worked for years
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on the Cameroonian national radio and television,
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and he spoke about health issues. He was a health correspondent.
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So we figured we'd hire this person -- when we got there he could
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be a great communicator.
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When we would get to these rural villages, though, what we found out
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is that no one had television,
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so they wouldn't recognize his face.
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But -- when he began to speak
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they would actually recognize his voice from the radio.
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And this was somebody who had incredible
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potential to spread aspects of our message,
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whether it be with regards to wildlife conservation
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or health prevention.
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Often we run into obstacles. This is us coming back from
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one of these very rural sites,
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with specimens from 200 individuals
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that we needed to get back to the lab within 48 hours.
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I like to show this shot -- this is
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Ubald Tamoufe, who's the lead
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investigator in our Cameroon site.
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Ubald laughs at me when I show this photo
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because of course you can't see his face.
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But the reason I like to show the shot
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is because you can see that he's about to solve this problem.
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(Laughter)
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Which -- which he did, which he did.
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Just a few quick before and after shots.
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This was our laboratory before.
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This is what it looks like now.
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Early on, in order to ship our specimens,
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we had to have dry ice. To get dry ice we had to go
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to the breweries -- beg, borrow, steal to get these folks to give it to us.
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Now we have our own liquid nitrogen.
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I like to call our laboratory the coldest place in Central Africa -- it might be.
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And here's a shot of me, this is the before shot of me.
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(Laughter)
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No comment.
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So what happened? So during the 10 years that we've been doing
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this work, we actually surprised ourselves.
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We made a number of discoveries.
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And what we've found is that if you look in the right place,
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you can actually monitor the flow
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of these viruses into human populations.
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That gave us a tremendous amount of hope.
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What we've found is a whole range of new viruses in these individuals,
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including new viruses in the same group
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as HIV -- so, brand new retroviruses.
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And let's face it, any new retrovirus in the
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human population -- it's something we should be aware of.
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It's something we should be following. It's not something
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that we should be surprised by.
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Needless to say in the past
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these viruses entering into these rural communities
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might very well have gone extinct.
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That's no longer the case. Logging roads provide access to urban areas.
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And critically, what happens in central Africa
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doesn't stay in Central Africa.
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So, once we discovered that it was really possible
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that we could actually do this monitoring,
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we decided to move this from research, to
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really attempt to phase up to a global monitoring effort.
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Through generous support and partnership
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scientifically with Google.org and the Skoll Foundation,
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we were able to start the Global Viral Forecasting Initiative
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and begin work in four different sites
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in Africa and Asia.
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Needless to say, different populations from different parts of the world
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have different sorts of contact.
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So it's not just hunters in Central Africa.
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It's also working in live animal markets --
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these wet markets -- which is exactly the place where
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SARS emerged in Asia.
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But really, this is just the beginning from our perspective.
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Our objective right now, in addition to
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deploying to these sites and getting everything moving,
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is to identify new partners
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because we feel like this effort needs to be extended
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to probably 20 or more sites throughout the world -- to viral hotspots --
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because really the idea here is to cast an incredibly wide net
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so that we can catch these things, ideally,
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before they make it to blood banks,
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sexual networks, airplanes. And that's really our objective.
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There was a time not very long ago
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when the discovery of unknown organisms
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was something that held incredible awe for us.
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It had potential to really change the way that we saw ourselves,
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and thought about ourselves.
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Many people, I think, on our planet right now
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despair, and they think
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we've reached a point where we've discovered most of the things.
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I'm going tell you right now: please don't despair.
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If an intelligent extra-terrestrial
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was taxed with writing the encyclopedia of life on our planet,
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27 out of 30 of these volumes
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would be devoted to bacteria and virus,
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with just a few of the volumes left
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for plants, fungus and animals,
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humans being a footnote;
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interesting footnote but a footnote nonetheless.
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This is honestly the most exciting period
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ever for the study of unknown life forms on our planet.
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The dominant things that exist here
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we know almost nothing about.
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And yet finally, we have the tools, which will allow us to actually explore that world
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and understand them.
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Thank you very much.
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(Applause)
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