0:00:27.900,0:00:33.766
(Mosquito buzzing)

0:00:42.040,0:00:43.240
(Swat)

0:00:45.580,0:00:46.730
Gotcha.

0:00:48.060,0:00:49.260
Mosquitoes.

0:00:49.980,0:00:51.180
I hate them.

0:00:52.220,0:00:53.420
Don't you?

0:00:54.060,0:00:56.676
That awful buzzing sound at night[br]around your ears

0:00:56.700,0:00:58.300
that drives you absolutely crazy?

0:00:59.380,0:01:01.876
Knowing that she wants[br]to stick a needle in your skin

0:01:01.900,0:01:03.100
and suck out your blood?

0:01:03.620,0:01:04.819
That's awful, right?

0:01:05.379,0:01:09.940
In fact, there's only one good thing[br]I can think of when it gets to mosquitoes.

0:01:11.100,0:01:13.020
When they fly into our bedroom at night,

0:01:13.900,0:01:15.234
they prefer to bite my wife.

0:01:15.701,0:01:16.916
(Laughter)

0:01:16.940,0:01:18.396
But that's fascinating, right?

0:01:18.420,0:01:21.860
Why does she receive more bites than I do?

0:01:22.700,0:01:25.116
And the answer is smell,

0:01:25.140,0:01:26.340
the smell of her body.

0:01:27.220,0:01:31.076
And since we all smell different[br]and produce chemicals on our skin

0:01:31.100,0:01:34.036
that either attract or repel mosquitoes,

0:01:34.060,0:01:36.740
some of us are just[br]more attractive than others.

0:01:37.460,0:01:42.700
So my wife smells nicer than I do,[br]or I just stink more than she does.

0:01:43.660,0:01:49.876
Either way, mosquitoes find us in the dark[br]by sniffing us out. They smell us.

0:01:49.900,0:01:53.196
And during my PhD,[br]I wanted to know exactly

0:01:53.220,0:01:57.300
what chemicals from our skin[br]African malaria mosquitoes use

0:01:57.324,0:01:58.564
to track us down at night.

0:01:59.780,0:02:02.420
And there's a whole range[br]of compounds that they do use.

0:02:02.860,0:02:04.900
And this was not going to be an easy task.

0:02:05.700,0:02:08.740
And therefore we set up[br]various experiments.

0:02:09.740,0:02:11.916
Why did we set up these experiments?

0:02:11.940,0:02:14.236
Because half the world's population

0:02:14.260,0:02:18.556
runs the risk of contracting[br]a killer disease like malaria

0:02:18.580,0:02:20.140
through a simple mosquito bite.

0:02:20.940,0:02:23.356
Every 30 seconds,[br]somewhere on this planet,

0:02:23.380,0:02:25.836
a child dies of malaria,

0:02:25.860,0:02:28.756
and Paul Levy this morning,[br]he was talking about the metaphor

0:02:28.780,0:02:31.276
of the 727 crashing[br]into the United States.

0:02:31.300,0:02:36.956
Well, in Africa, we have[br]the equivalent of seven jumbo 747s

0:02:36.980,0:02:38.260
crashing every day.

0:02:39.420,0:02:42.715
But perhaps if we can attract[br]these mosquitoes to traps,

0:02:42.739,0:02:44.316
bait it with our smell,

0:02:44.340,0:02:47.260
we may be able[br]to stop transmission of disease.

0:02:48.460,0:02:50.676
Now, solving this puzzle[br]was not an easy thing,

0:02:50.700,0:02:53.676
because we produce hundreds[br]of different chemicals on the skin,

0:02:53.700,0:02:56.356
but we undertook[br]some remarkable experiments

0:02:56.380,0:02:59.676
that managed us to resolve[br]this puzzle very quickly indeed.

0:02:59.700,0:03:03.036
First, we observed[br]that not all mosquito species

0:03:03.060,0:03:04.980
bite on the same part of the body.

0:03:05.700,0:03:06.916
Strange.

0:03:06.940,0:03:08.516
So we set up an experiment

0:03:08.540,0:03:11.897
where we put a naked volunteer[br]in a large cage,

0:03:11.921,0:03:12.936
(Laughter)

0:03:12.960,0:03:15.396
and in that cage, we released mosquitoes

0:03:15.420,0:03:18.100
to see where they were biting[br]on the body of that person.

0:03:18.700,0:03:20.660
And we found some remarkable differences.

0:03:21.100,0:03:24.116
On the left here you see the bites

0:03:24.140,0:03:26.396
by the Dutch malaria mosquito[br]on this person.

0:03:26.420,0:03:29.100
They had a very strong preference[br]for biting on the face.

0:03:29.940,0:03:32.436
In contrast, the African malaria mosquito

0:03:32.460,0:03:37.636
had a very strong preference for biting[br]the ankles and feet of this person.

0:03:37.660,0:03:40.116
And that, of course,[br]we should have known all along,

0:03:40.140,0:03:43.276
because they're called[br]mosqui-toes, you see?

0:03:43.300,0:03:44.636
(Laughter)

0:03:44.660,0:03:45.876
That's right.

0:03:45.900,0:03:48.156
(Applause)

0:03:48.180,0:03:52.540
And so we started[br]focusing on the smell of feet ...

0:03:53.340,0:03:55.156
on the smell of human feet,

0:03:55.180,0:03:58.916
until we came across[br]a remarkable statement in the literature

0:03:58.940,0:04:02.716
that said that cheese smells after feet

0:04:02.740,0:04:04.340
rather than the reverse.

0:04:04.940,0:04:06.396
Think of it.

0:04:06.420,0:04:08.849
And this triggered us[br]to do a remarkable experiment.

0:04:08.873,0:04:13.916
We tried, with a tiny little piece[br]of Limburger cheese,

0:04:13.940,0:04:15.700
which smells badly after feet,

0:04:16.339,0:04:18.476
to attract African malaria mosquitoes.

0:04:18.500,0:04:20.380
And you know what? It worked.

0:04:21.540,0:04:24.516
In fact, it worked so well

0:04:24.540,0:04:29.076
that now we have a synthetic mixture[br]of the aroma of Limburger cheese

0:04:29.100,0:04:30.876
that we're using in Tanzania

0:04:30.900,0:04:32.116
and has been shown there

0:04:32.140,0:04:36.100
to be two to three times[br]more attractive to mosquitoes than humans.

0:04:36.860,0:04:40.356
Limburg, be proud of your cheese,

0:04:40.380,0:04:43.516
as it is now used[br]in the fight against malaria.

0:04:43.540,0:04:49.798
(Applause)

0:04:50.379,0:04:52.499
That's the cheese, just to show you.

0:04:53.499,0:04:55.980
My second story is remarkable as well.

0:04:56.820,0:04:59.180
It's about man's best friend.[br]It's about dogs.

0:05:00.060,0:05:03.420
And I will show you how we can use dogs[br]in the fight against malaria.

0:05:04.980,0:05:07.836
One of the best ways of killing mosquitoes

0:05:07.860,0:05:11.156
is not to wait until[br]they fly around like adults

0:05:11.180,0:05:13.060
and bite people and transmit disease.

0:05:13.900,0:05:17.300
It's to kill them when they're still[br]in the water as larvae.

0:05:18.020,0:05:19.236
Why?

0:05:19.260,0:05:21.620
Because they are just like the CIA.

0:05:22.580,0:05:26.556
In that pool of water,[br]these larvae are concentrated.

0:05:26.580,0:05:29.236
They're all together there.[br]They are immobile.

0:05:29.260,0:05:30.916
They can't escape from that water.

0:05:30.940,0:05:32.516
They can't fly.

0:05:32.540,0:05:35.236
And they're accessible.

0:05:35.260,0:05:39.300
You can actually walk up to that pool[br]and you can kill them there, right?

0:05:40.220,0:05:43.836
So the problem that we face with this

0:05:43.860,0:05:47.756
is that, throughout the landscape,[br]all these pools of water with the larvae,

0:05:47.780,0:05:49.756
they are scattered all over the place,

0:05:49.780,0:05:52.996
which makes it very hard[br]for an inspector like this

0:05:53.020,0:05:56.580
to actually find all these breeding sites[br]and treat them with insecticides.

0:05:57.140,0:06:01.340
And last year we thought very, very hard,[br]how can we resolve this problem?

0:06:02.060,0:06:06.516
Until we realized that just like us --[br]we have a unique smell --

0:06:06.540,0:06:09.820
mosquito larvae[br]also have a very unique smell.

0:06:10.580,0:06:12.756
And so we set up another crazy experiment,

0:06:12.780,0:06:15.116
because we collected[br]the smell of these larvae,

0:06:15.140,0:06:18.420
put it on pieces of cloth,[br]and then did something very remarkable.

0:06:19.060,0:06:21.476
Here we have a bar with four holes

0:06:21.500,0:06:24.276
and we put the smell[br]of these larvae in the left hole.

0:06:24.300,0:06:25.516
Oh, that was very quick.

0:06:25.540,0:06:28.676
And then you see the dog.[br]It's called Tweed. It's a border collie.

0:06:28.700,0:06:31.316
He's examining these holes[br]and now he's got it already.

0:06:31.340,0:06:33.676
He's going back to check[br]the control holes again,

0:06:33.700,0:06:35.556
but he's coming back to the first one,

0:06:35.580,0:06:37.396
and now he's locking into that smell,

0:06:37.420,0:06:41.036
which means that now,[br]we can use dogs with these inspectors

0:06:41.060,0:06:44.276
to much better find the breeding sites[br]of mosquitoes in the field,

0:06:44.300,0:06:46.700
and therefore have[br]a much bigger impact on malaria.

0:06:47.420,0:06:49.036
This lady is Ellen van der Zweep.

0:06:49.060,0:06:51.299
She's one of the best[br]dog trainers in the world,

0:06:51.323,0:06:53.363
and she believes[br]that we can do a lot more.

0:06:54.260,0:06:57.716
Since we also know that people[br]that carry malaria parasites

0:06:57.740,0:07:00.596
smell different compared to people[br]that are uninfected,

0:07:00.620,0:07:05.020
she's convinced that we can train dogs[br]to find people that carry the parasite.

0:07:06.900,0:07:10.316
That means that in a population[br]where malaria has gone down all the way

0:07:10.340,0:07:12.756
and there's few people[br]remaining with parasites,

0:07:12.780,0:07:14.516
that the dogs can find these people,

0:07:14.540,0:07:18.436
we can treat them with antimalarial drugs[br]and give the final blow to malaria.

0:07:18.460,0:07:20.740
Man's best friend[br]in the fight against malaria.

0:07:22.180,0:07:24.546
My third story is perhaps[br]even more remarkable ...

0:07:25.380,0:07:28.856
and, I should say, has never been shown[br]to the public until today.

0:07:28.880,0:07:29.881
(Audience cheers)

0:07:29.905,0:07:31.105
Yeah.

0:07:31.860,0:07:36.836
It's a crazy story, but I believe[br]it's perhaps the best and ultimate revenge

0:07:36.860,0:07:38.060
against mosquitoes ever.

0:07:38.540,0:07:40.036
In fact, people have told me

0:07:40.060,0:07:43.540
that now they will enjoy[br]being bitten by mosquitoes.

0:07:44.620,0:07:46.156
And the question of course is,

0:07:46.180,0:07:49.340
what would make someone[br]enjoy being bitten by mosquitoes?

0:07:49.900,0:07:52.220
And the answer I have right here ...

0:07:53.180,0:07:54.622
in my pocket --

0:07:54.646,0:07:55.647
(Laughter)

0:07:55.671,0:07:56.871
if I get it.

0:07:58.060,0:07:59.260
It's a tablet.

0:08:00.100,0:08:01.316
A simple tablet,

0:08:01.340,0:08:03.700
and when I take it with water ...

0:08:04.580,0:08:06.180
it does miracles.

0:08:09.060,0:08:10.340
Thank you.

0:08:16.460,0:08:19.380
Now, let me show you how this works.

0:08:20.060,0:08:22.780
Here in this box, I have a cage

0:08:24.114,0:08:31.092
with several hundred[br]hungry female mosquitoes ...

0:08:31.116,0:08:32.395
(Laughter)

0:08:32.419,0:08:34.876
that I'm just about to release.

0:08:34.900,0:08:36.676
(Laughter)

0:08:36.700,0:08:38.041
Just kidding, just kidding.

0:08:38.065,0:08:39.436
(Laughter)

0:08:39.460,0:08:42.515
What I'm going to show you[br]is, I'm gonna stick my arm into it

0:08:42.539,0:08:44.820
and I will show you[br]how quickly they will bite.

0:08:45.580,0:08:46.780
There we go.

0:08:47.580,0:08:49.771
Don't worry, I do this[br]all the time in the lab.

0:08:50.420,0:08:51.620
There we go.

0:08:52.660,0:08:53.860
OK.

0:08:54.340,0:08:56.340
Now, on the video --

0:08:57.420,0:08:59.236
on the video here,

0:08:59.260,0:09:01.396
I'm going to show you[br]exactly the same thing,

0:09:01.420,0:09:03.556
except that what[br]I'm showing you on the video

0:09:03.580,0:09:06.380
happened one hour after I took the tablet.

0:09:06.899,0:09:08.100
Have a look.

0:09:08.820,0:09:10.036
That doesn't work.

0:09:10.060,0:09:11.259
OK. Sorry about that.

0:09:11.700,0:09:14.676
I'm sticking in my arm,[br]I'm giving them a big juicy blood meal,

0:09:14.700,0:09:17.196
I'm shaking them off,[br]and we follow them through time

0:09:17.220,0:09:19.716
to see these mosquitoes[br]get very, very sick indeed,

0:09:19.740,0:09:21.260
here shown in fast motion.

0:09:22.020,0:09:25.956
And three hours later,[br]what we see at the bottom of the cage

0:09:25.980,0:09:27.180
is dead mosquitoes ...

0:09:28.100,0:09:30.060
very dead mosquitoes.

0:09:30.900,0:09:32.916
And I'm going to say,[br]ladies and gentlemen,

0:09:32.940,0:09:34.940
we have swapped the cards with mosquitoes.

0:09:34.964,0:09:38.516
They don't kill us. We kill them.

0:09:38.540,0:09:45.540
(Applause)

0:09:47.740,0:09:48.940
Now --

0:09:50.060,0:09:53.236
(Laughter)

0:09:53.260,0:09:54.780
Maastricht, be prepared.

0:09:55.500,0:09:57.396
Now, think of what we can do with this.

0:09:57.420,0:09:59.556
We can actually use this[br]to contain outbreaks

0:09:59.580,0:10:02.660
of mosquito-born diseases,[br]of epidemics, right?

0:10:03.260,0:10:05.276
And better still,[br]imagine what would happen

0:10:05.300,0:10:09.500
if, in a very large area, everyone would[br]take this drug, for just three weeks.

0:10:10.020,0:10:11.636
That would give us an opportunity

0:10:11.660,0:10:13.780
to actually eliminate[br]malaria as a disease.

0:10:14.460,0:10:18.396
So cheese, dogs and a pill[br]to kill mosquitoes.

0:10:18.420,0:10:21.380
That's the kind of out-of-the-box[br]science that I love doing ...

0:10:22.260,0:10:24.236
for the betterment of mankind,

0:10:24.260,0:10:25.876
but especially for her,

0:10:25.900,0:10:29.796
so that she can grow up[br]in a world without malaria.

0:10:29.820,0:10:31.036
Thank you.

0:10:31.060,0:10:32.441
(Applause)