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

314,334 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
0
18330
2000
00:20
of AIDS, they're gonna think back to the 1980s.
1
20330
3000
00:23
And certainly, this was the decade in which we discovered AIDS
2
23330
3000
00:26
and the virus that causes it, HIV.
3
26330
3000
00:29
But in fact this virus crossed over into humans many decades before,
4
29330
4000
00:33
from chimpanzees, where the virus originated, into humans who hunt these apes.
5
33330
4000
00:37
This photo was taken before the Great Depression
6
37330
3000
00:40
in Brazzaville, Congo.
7
40330
2000
00:42
At this time, there were thousands of individuals,
8
42330
2000
00:44
we think, that were infected with HIV.
9
44330
2000
00:46
So I have a couple of really important questions for you.
10
46330
2000
00:48
If this virus was in thousands
11
48330
1000
00:49
of individuals at this point,
12
49330
2000
00:51
why was it the case that it took us until 1984
13
51330
3000
00:54
to be able to discover this virus?
14
54330
2000
00:56
OK now, more importantly,
15
56330
2000
00:58
had we been there in the '40s and '50s, '60s,
16
58330
3000
01:01
had we seen this disease, had we understood
17
61330
3000
01:04
exactly what was going on with it, how might that have changed and completely
18
64330
3000
01:07
transformed the nature of the way this pandemic moved?
19
67330
5000
01:12
In fact, this is not unique to HIV. The vast majority of
20
72330
3000
01:15
viruses come from animals.
21
75330
2000
01:17
And you can kind of think of this as a pyramid of this bubbling up of viruses
22
77330
3000
01:20
from animals into human populations.
23
80330
2000
01:22
But only at the very top of this pyramid do these things become completely human.
24
82330
3000
01:25
Nevertheless, we spend the vast majority
25
85330
3000
01:28
of our energy focused on this level of the pyramid,
26
88330
2000
01:30
trying to tackle things that are already completely adapted to human beings,
27
90330
4000
01:34
that are going to be very very difficult to address --
28
94330
2000
01:36
as we've seen in the case of HIV.
29
96330
2000
01:38
So during the last 15 years,
30
98330
2000
01:40
I've been working to actually study the earlier interface here --
31
100330
3000
01:43
what I've labeled "viral chatter," which was a term coined
32
103330
2000
01:45
by my mentor Don Burke.
33
105330
2000
01:47
This is the idea that we can study the sort of
34
107330
2000
01:49
pinging of these viruses into human populations,
35
109330
3000
01:52
the movement of these agents over into humans;
36
112330
2000
01:54
and by capturing this moment,
37
114330
2000
01:56
we might be able to move to a situation where we can catch them early.
38
116330
3000
01:59
OK, so this is a picture, and I'm going to show you
39
119330
2000
02:01
some pictures now from the field.
40
121330
2000
02:03
This is a picture of a central African hunter.
41
123330
2000
02:05
It's actually a fairly common picture.
42
125330
2000
02:07
One of the things I want you to note from it
43
127330
2000
02:09
is blood -- that you see a tremendous amount of blood contact.
44
129330
3000
02:12
This was absolutely key for us. This is a
45
132330
2000
02:14
very intimate form of connection.
46
134330
2000
02:16
So if we're going to study viral chatter, we need to
47
136330
2000
02:18
get to these populations who have intensive contact with wild animals.
48
138330
3000
02:21
And so we've been studying people like this individual.
49
141330
4000
02:25
We collect blood from them, other specimens.
50
145330
3000
02:28
We look at the diseases, which are in the animals as well as the humans.
51
148330
3000
02:31
And ideally, this is going to allow us to catch these things
52
151330
3000
02:34
early on, as they're moving over into human populations.
53
154330
3000
02:37
And the basic objective of this work is not to just
54
157330
2000
02:39
go out once and look at these individuals,
55
159330
2000
02:41
but to establish thousands of individuals
56
161330
2000
02:43
in these populations that we would monitor
57
163330
3000
02:46
continuously on a regular basis.
58
166330
2000
02:48
When they were sick, we would collect specimens from them.
59
168330
2000
02:50
We would actually enlist them --
60
170330
2000
02:52
which we've done now -- to collect specimens from animals.
61
172330
2000
02:54
We give them these little pieces of filter paper.
62
174330
2000
02:56
When they sample from animals,
63
176330
2000
02:58
they collect the blood on the filter paper
64
178330
2000
03:00
and this allows us to identify yet-unknown viruses from exactly the right animals --
65
180330
4000
03:04
the ones that are actually being hunted.
66
184330
3000
03:10
(Video) Narrator: Deep in a remote region of Cameroon,
67
190330
2000
03:12
two hunters stalk their prey.
68
192330
3000
03:15
Their names are Patrice and Patee.
69
195330
2000
03:17
They're searching for bush meat;
70
197330
3000
03:20
forest animals they can kill to feed their families.
71
200330
4000
03:24
Patrice and Patee set out most days to go out hunting
72
204330
2000
03:26
in the forest around their homes.
73
206330
3000
03:29
They have a series of traps, of snares that they've set up
74
209330
2000
03:31
to catch wild pigs, snakes, monkeys,
75
211330
4000
03:35
rodents -- anything they can, really.
76
215330
4000
03:39
Patrice and Patee have been out for hours but found nothing.
77
219330
6000
03:45
The animals are simply gone.
78
225330
4000
03:49
We stop for a drink of water.
79
229330
5000
03:54
Then there is a rustle in the brush.
80
234330
5000
03:59
A group of hunters approach,
81
239330
5000
04:04
their packs loaded with wild game.
82
244330
4000
04:08
There's at least three viruses
83
248330
2000
04:10
that you know about, which are in this particular monkey.
84
250330
3000
04:13
Nathan Wolfe: This species, yeah. And there's many many more pathogens
85
253330
2000
04:15
that are present in these animals.
86
255330
2000
04:17
These individuals are at specific risk,
87
257330
3000
04:20
particularly if there's blood contact, they're at risk for transmission
88
260330
3000
04:23
and possibly infection with novel viruses.
89
263330
5000
04:28
Narrator: As the hunters display their kills, something surprising happens.
90
268330
3000
04:31
They show us filter paper they've used to collect the animals' blood.
91
271330
4000
04:35
The blood will be tested for zoonotic viruses,
92
275330
3000
04:38
part of a program Dr. Wolfe has spent years setting up.
93
278330
3000
04:41
NW: So this is from this animal right here,
94
281330
2000
04:43
Greater Spot-Nosed Guenon.
95
283330
2000
04:45
Every person who has one of those filter papers has at least,
96
285330
2000
04:47
at a minimum, been through our basic health education
97
287330
3000
04:50
about the risks associated with these activities,
98
290330
3000
04:53
which presumably, from our perspective,
99
293330
2000
04:55
gives them the ability to decrease their own risk,
100
295330
2000
04:57
and then obviously the risk to their families,
101
297330
3000
05:00
the village, the country, and the world.
102
300330
4000
05:04
NW: OK, before I continue, I think it's important to take just a moment
103
304330
3000
05:07
to talk about bush meat. Bush meat is the hunting of wild game.
104
307330
3000
05:10
OK? And you can consider all sorts of different bush meat.
105
310330
2000
05:12
I'm going to be talking about this.
106
312330
2000
05:14
When your children and grandchildren
107
314330
2000
05:16
sort of pose questions to you about this period of time,
108
316330
2000
05:18
one of the things they're gonna ask you,
109
318330
2000
05:20
is how it was they we allowed some of our closest living relatives,
110
320330
3000
05:23
some of the most valuable and endangered species
111
323330
2000
05:25
on our planet, to go extinct because we
112
325330
3000
05:28
weren't able to address some of the issues
113
328330
2000
05:30
of poverty in these parts of the world.
114
330330
2000
05:32
But in fact that's not the only question they're going to ask you about this.
115
332330
3000
05:35
They're also going to ask you the question
116
335330
2000
05:37
that when we knew that this was the way that HIV entered
117
337330
2000
05:39
into the human population,
118
339330
2000
05:41
and that other diseases had the potential to enter like this,
119
341330
2000
05:43
why did we let these behaviors continue?
120
343330
2000
05:45
Why did we not find some other solution to this?
121
345330
2000
05:47
They're going to say, in regions of profound
122
347330
3000
05:50
instability throughout the world,
123
350330
2000
05:52
where you have intense poverty, where populations are growing
124
352330
3000
05:55
and you don't have sustainable resources like this,
125
355330
2000
05:57
this is going to lead to food insecurity.
126
357330
5000
06:02
But they're also going to ask you probably a different question.
127
362330
2000
06:04
It's one that I think we all need to ask ourselves,
128
364330
2000
06:06
which is, why we thought the responsibility rested with this individual here.
129
366330
4000
06:10
Now this is the individual -- you can see just right up over his right shoulder --
130
370330
3000
06:13
this is the individual that hunted the monkey
131
373330
2000
06:15
from the last picture that I showed you.
132
375330
2000
06:17
OK, take a look at his shirt.
133
377330
2000
06:19
You know, take a look at his face.
134
379330
3000
06:22
Bush meat is one of the central crises,
135
382330
3000
06:25
which is occurring in our population right now,
136
385330
2000
06:27
in humanity, on this planet.
137
387330
2000
06:29
But it can't be the fault of somebody like this.
138
389330
3000
06:32
OK? And solving it cannot be his responsibility alone.
139
392330
4000
06:36
There's no easy solutions,
140
396330
2000
06:38
but what I'm saying to you is that we neglect this problem
141
398330
2000
06:40
at our own peril.
142
400330
2000
06:42
So, in 1998, along with my mentors
143
402330
3000
06:45
Don Burke and Colonel Mpoudi-Ngole,
144
405330
2000
06:47
we went to actually start this work
145
407330
2000
06:49
in Central Africa, to work with hunters
146
409330
2000
06:51
in this part of the world.
147
411330
2000
06:53
And my job -- at that time I was a post-doctoral fellow,
148
413330
3000
06:56
and I was really tasked with setting this up.
149
416330
2000
06:58
So I said to myself, "OK, great --
150
418330
2000
07:00
we're gonna collect all kinds of specimens. We're gonna go to all these
151
420330
2000
07:02
different locations. It's going to be wonderful."
152
422330
3000
07:05
You know, I looked at the map; I picked out 17 sites;
153
425330
2000
07:07
I figured, no problem.
154
427330
2000
07:09
(Laughter)
155
429330
2000
07:11
Needless to say, I was drastically wrong.
156
431330
2000
07:13
This is challenging work to do.
157
433330
2000
07:15
Fortunately, I had and continue to have
158
435330
2000
07:17
an absolutely wonderful team of colleagues and collaborators in my own team,
159
437330
3000
07:20
and that's the only way that this work can really occur.
160
440330
2000
07:22
We have a whole range of challenges about this work.
161
442330
3000
07:25
One of them is just obtaining trust
162
445330
2000
07:27
from individuals that we work with in the field.
163
447330
2000
07:29
The person you see on the right hand side is Paul DeLong-Minutu.
164
449330
4000
07:33
He's one of the best communicators that I've really ever dealt with.
165
453330
2000
07:35
When I arrived I didn't speak a word of French,
166
455330
2000
07:37
and I still seemed to understand what it was he was saying.
167
457330
3000
07:40
Paul worked for years
168
460330
2000
07:42
on the Cameroonian national radio and television,
169
462330
2000
07:44
and he spoke about health issues. He was a health correspondent.
170
464330
3000
07:47
So we figured we'd hire this person -- when we got there he could
171
467330
2000
07:49
be a great communicator.
172
469330
2000
07:51
When we would get to these rural villages, though, what we found out
173
471330
2000
07:53
is that no one had television,
174
473330
2000
07:55
so they wouldn't recognize his face.
175
475330
3000
07:58
But -- when he began to speak
176
478330
3000
08:01
they would actually recognize his voice from the radio.
177
481330
2000
08:03
And this was somebody who had incredible
178
483330
2000
08:05
potential to spread aspects of our message,
179
485330
2000
08:07
whether it be with regards to wildlife conservation
180
487330
3000
08:10
or health prevention.
181
490330
3000
08:13
Often we run into obstacles. This is us coming back from
182
493330
2000
08:15
one of these very rural sites,
183
495330
2000
08:17
with specimens from 200 individuals
184
497330
2000
08:19
that we needed to get back to the lab within 48 hours.
185
499330
2000
08:21
I like to show this shot -- this is
186
501330
2000
08:23
Ubald Tamoufe, who's the lead
187
503330
2000
08:25
investigator in our Cameroon site.
188
505330
2000
08:27
Ubald laughs at me when I show this photo
189
507330
2000
08:29
because of course you can't see his face.
190
509330
2000
08:31
But the reason I like to show the shot
191
511330
2000
08:33
is because you can see that he's about to solve this problem.
192
513330
3000
08:36
(Laughter)
193
516330
1000
08:37
Which -- which he did, which he did.
194
517330
3000
08:40
Just a few quick before and after shots.
195
520330
2000
08:42
This was our laboratory before.
196
522330
3000
08:45
This is what it looks like now.
197
525330
2000
08:47
Early on, in order to ship our specimens,
198
527330
2000
08:49
we had to have dry ice. To get dry ice we had to go
199
529330
2000
08:51
to the breweries -- beg, borrow, steal to get these folks to give it to us.
200
531330
3000
08:54
Now we have our own liquid nitrogen.
201
534330
3000
08:57
I like to call our laboratory the coldest place in Central Africa -- it might be.
202
537330
5000
09:02
And here's a shot of me, this is the before shot of me.
203
542330
4000
09:06
(Laughter)
204
546330
2000
09:08
No comment.
205
548330
2000
09:10
So what happened? So during the 10 years that we've been doing
206
550330
2000
09:12
this work, we actually surprised ourselves.
207
552330
3000
09:15
We made a number of discoveries.
208
555330
3000
09:18
And what we've found is that if you look in the right place,
209
558330
2000
09:20
you can actually monitor the flow
210
560330
2000
09:22
of these viruses into human populations.
211
562330
2000
09:24
That gave us a tremendous amount of hope.
212
564330
2000
09:26
What we've found is a whole range of new viruses in these individuals,
213
566330
3000
09:29
including new viruses in the same group
214
569330
2000
09:31
as HIV -- so, brand new retroviruses.
215
571330
3000
09:34
And let's face it, any new retrovirus in the
216
574330
2000
09:36
human population -- it's something we should be aware of.
217
576330
3000
09:39
It's something we should be following. It's not something
218
579330
2000
09:41
that we should be surprised by.
219
581330
2000
09:43
Needless to say in the past
220
583330
2000
09:45
these viruses entering into these rural communities
221
585330
2000
09:47
might very well have gone extinct.
222
587330
2000
09:49
That's no longer the case. Logging roads provide access to urban areas.
223
589330
4000
09:53
And critically, what happens in central Africa
224
593330
4000
09:57
doesn't stay in Central Africa.
225
597330
3000
10:00
So, once we discovered that it was really possible
226
600330
2000
10:02
that we could actually do this monitoring,
227
602330
2000
10:04
we decided to move this from research, to
228
604330
2000
10:06
really attempt to phase up to a global monitoring effort.
229
606330
4000
10:10
Through generous support and partnership
230
610330
2000
10:12
scientifically with Google.org and the Skoll Foundation,
231
612330
3000
10:15
we were able to start the Global Viral Forecasting Initiative
232
615330
4000
10:19
and begin work in four different sites
233
619330
2000
10:21
in Africa and Asia.
234
621330
3000
10:24
Needless to say, different populations from different parts of the world
235
624330
2000
10:26
have different sorts of contact.
236
626330
2000
10:28
So it's not just hunters in Central Africa.
237
628330
3000
10:31
It's also working in live animal markets --
238
631330
2000
10:33
these wet markets -- which is exactly the place where
239
633330
2000
10:35
SARS emerged in Asia.
240
635330
2000
10:37
But really, this is just the beginning from our perspective.
241
637330
2000
10:39
Our objective right now, in addition to
242
639330
2000
10:41
deploying to these sites and getting everything moving,
243
641330
2000
10:43
is to identify new partners
244
643330
2000
10:45
because we feel like this effort needs to be extended
245
645330
3000
10:48
to probably 20 or more sites throughout the world -- to viral hotspots --
246
648330
4000
10:52
because really the idea here is to cast an incredibly wide net
247
652330
3000
10:55
so that we can catch these things, ideally,
248
655330
2000
10:57
before they make it to blood banks,
249
657330
2000
10:59
sexual networks, airplanes. And that's really our objective.
250
659330
4000
11:03
There was a time not very long ago
251
663330
2000
11:05
when the discovery of unknown organisms
252
665330
2000
11:07
was something that held incredible awe for us.
253
667330
3000
11:10
It had potential to really change the way that we saw ourselves,
254
670330
3000
11:13
and thought about ourselves.
255
673330
2000
11:15
Many people, I think, on our planet right now
256
675330
2000
11:17
despair, and they think
257
677330
3000
11:20
we've reached a point where we've discovered most of the things.
258
680330
3000
11:23
I'm going tell you right now: please don't despair.
259
683330
3000
11:26
If an intelligent extra-terrestrial
260
686330
2000
11:28
was taxed with writing the encyclopedia of life on our planet,
261
688330
3000
11:31
27 out of 30 of these volumes
262
691330
2000
11:33
would be devoted to bacteria and virus,
263
693330
3000
11:36
with just a few of the volumes left
264
696330
2000
11:38
for plants, fungus and animals,
265
698330
2000
11:40
humans being a footnote;
266
700330
3000
11:43
interesting footnote but a footnote nonetheless.
267
703330
3000
11:46
This is honestly the most exciting period
268
706330
3000
11:49
ever for the study of unknown life forms on our planet.
269
709330
4000
11:53
The dominant things that exist here
270
713330
2000
11:55
we know almost nothing about.
271
715330
2000
11:57
And yet finally, we have the tools, which will allow us to actually explore that world
272
717330
3000
12:00
and understand them.
273
720330
4000
12:04
Thank you very much.
274
724330
2000
12:06
(Applause)
275
726330
6000
About this website

This site will introduce you to YouTube videos that are useful for learning English. You will see English lessons taught by top-notch teachers from around the world. Double-click on the English subtitles displayed on each video page to play the video from there. The subtitles scroll in sync with the video playback. If you have any comments or requests, please contact us using this contact form.

https://forms.gle/WvT1wiN1qDtmnspy7