0:00:00.800,0:00:06.666
(Mosquito buzzing)

0:00:10.040,0:00:11.240
(Swat)

0:00:13.480,0:00:14.630
Gotcha.

0:00:15.960,0:00:17.160
Mosquitoes.

0:00:17.880,0:00:19.080
I hate them.

0:00:20.120,0:00:21.320
Don't you?

0:00:21.960,0:00:24.576
That awful buzzing sound at night[br]around your ears

0:00:24.600,0:00:26.200
that drives you absolutely crazy?

0:00:27.280,0:00:29.776
Knowing that she wants[br]to stick a needle in your skin

0:00:29.800,0:00:31.000
and suck out your blood?

0:00:31.520,0:00:32.720
That's awful, right?

0:00:33.280,0:00:37.840
In fact, there's only one good thing[br]I can think of when it gets to mosquitoes.

0:00:39.000,0:00:40.920
When they fly into our bedroom at night,

0:00:41.800,0:00:43.134
they prefer to bite my wife.

0:00:43.601,0:00:44.816
(Laughter)

0:00:44.840,0:00:46.296
But that's fascinating, right?

0:00:46.320,0:00:49.760
Why does she receive more bites than I do?

0:00:50.600,0:00:53.016
And the answer is smell,

0:00:53.040,0:00:54.240
the smell of her body.

0:00:55.120,0:00:58.976
And since we all smell different[br]and produce chemicals on our skin

0:00:59.000,0:01:01.936
that either attract or repel mosquitoes,

0:01:01.960,0:01:04.640
some of us are just[br]more attractive than others.

0:01:05.360,0:01:10.600
So my wife smells nicer than I do,[br]or I just stink more than she does.

0:01:11.560,0:01:17.776
Either way, mosquitoes find us in the dark[br]by sniffing us out. They smell us.

0:01:17.800,0:01:21.096
And during my PhD,[br]I wanted to know exactly

0:01:21.120,0:01:25.200
what chemicals from our skin[br]African malaria mosquitoes use

0:01:25.224,0:01:26.464
to track us down at night.

0:01:27.680,0:01:30.320
And there's a whole range[br]of compounds that they do use.

0:01:30.760,0:01:32.800
And this was not going to be an easy task.

0:01:33.600,0:01:36.640
And therefore we set up[br]various experiments.

0:01:37.640,0:01:39.816
Why did we set up these experiments?

0:01:39.840,0:01:42.136
Because half the world's population

0:01:42.160,0:01:46.456
runs the risk of contracting[br]a killer disease like malaria

0:01:46.480,0:01:48.040
through a simple mosquito bite.

0:01:48.840,0:01:51.256
Every 30 seconds,[br]somewhere on this planet,

0:01:51.280,0:01:53.736
a child dies of malaria,

0:01:53.760,0:01:56.656
and Paul Levy this morning,[br]he was talking about the metaphor

0:01:56.680,0:01:59.176
of the 727 crashing[br]into the United States.

0:01:59.200,0:02:04.856
Well, in Africa, we have[br]the equivalent of seven jumbo 747s

0:02:04.880,0:02:06.160
crashing every day.

0:02:07.320,0:02:10.615
But perhaps if we can attract[br]these mosquitoes to traps,

0:02:10.639,0:02:12.216
bait it with our smell,

0:02:12.240,0:02:15.160
we may be able[br]to stop transmission of disease.

0:02:16.360,0:02:18.576
Now, solving this puzzle[br]was not an easy thing,

0:02:18.600,0:02:21.576
because we produce hundreds[br]of different chemicals on the skin,

0:02:21.600,0:02:24.256
but we undertook[br]some remarkable experiments

0:02:24.280,0:02:27.576
that managed us to resolve[br]this puzzle very quickly indeed.

0:02:27.600,0:02:30.936
First, we observed[br]that not all mosquito species

0:02:30.960,0:02:32.880
bite on the same part of the body.

0:02:33.600,0:02:34.816
Strange.

0:02:34.840,0:02:36.416
So we set up an experiment

0:02:36.440,0:02:39.797
where we put a naked volunteer[br]in a large cage,

0:02:39.821,0:02:40.836
(Laughter)

0:02:40.860,0:02:43.296
and in that cage, we released mosquitoes

0:02:43.320,0:02:46.000
to see where they were biting[br]on the body of that person.

0:02:46.600,0:02:48.560
And we found some remarkable differences.

0:02:49.000,0:02:52.016
On the left here you see the bites

0:02:52.040,0:02:54.296
by the Dutch malaria mosquito[br]on this person.

0:02:54.320,0:02:57.000
They had a very strong preference[br]for biting on the face.

0:02:57.840,0:03:00.336
In contrast, the African malaria mosquito

0:03:00.360,0:03:05.536
had a very strong preference for biting[br]the ankles and feet of this person.

0:03:05.560,0:03:08.016
And that, of course,[br]we should have known all along,

0:03:08.040,0:03:11.176
because they're called[br]mosqui-toes, you see?

0:03:11.200,0:03:12.536
(Laughter)

0:03:12.560,0:03:13.776
That's right.

0:03:13.800,0:03:16.056
(Applause)

0:03:16.080,0:03:20.440
And so we started[br]focusing on the smell of feet ...

0:03:21.240,0:03:23.056
on the smell of human feet,

0:03:23.080,0:03:26.816
until we came across[br]a remarkable statement in the literature

0:03:26.840,0:03:30.616
that said that cheese smells after feet

0:03:30.640,0:03:32.240
rather than the reverse.

0:03:32.840,0:03:34.296
Think of it.

0:03:34.320,0:03:36.749
And this triggered us[br]to do a remarkable experiment.

0:03:36.773,0:03:41.816
We tried, with a tiny little piece[br]of Limburger cheese,

0:03:41.840,0:03:43.600
which smells badly after feet,

0:03:44.240,0:03:46.376
to attract African malaria mosquitoes.

0:03:46.400,0:03:48.280
And you know what? It worked.

0:03:49.440,0:03:52.416
In fact, it worked so well

0:03:52.440,0:03:56.976
that now we have a synthetic mixture[br]of the aroma of Limburger cheese

0:03:57.000,0:03:58.776
that we're using in Tanzania

0:03:58.800,0:04:00.016
and has been shown there

0:04:00.040,0:04:04.000
to be two to three times[br]more attractive to mosquitoes than humans.

0:04:04.760,0:04:08.256
Limburg, be proud of your cheese,

0:04:08.280,0:04:11.416
as it is now used[br]in the fight against malaria.

0:04:11.440,0:04:17.698
(Applause)

0:04:18.279,0:04:20.399
That's the cheese, just to show you.

0:04:21.399,0:04:23.880
My second story is remarkable as well.

0:04:24.720,0:04:27.080
It's about man's best friend.[br]It's about dogs.

0:04:27.960,0:04:31.320
And I will show you how we can use dogs[br]in the fight against malaria.

0:04:32.880,0:04:35.736
One of the best ways of killing mosquitoes

0:04:35.760,0:04:39.056
is not to wait until[br]they fly around like adults

0:04:39.080,0:04:40.960
and bite people and transmit disease.

0:04:41.800,0:04:45.200
It's to kill them when they're still[br]in the water as larvae.

0:04:45.920,0:04:47.136
Why?

0:04:47.160,0:04:49.520
Because they are just like the CIA.

0:04:50.480,0:04:54.456
In that pool of water,[br]these larvae are concentrated.

0:04:54.480,0:04:57.136
They're all together there.[br]They are immobile.

0:04:57.160,0:04:58.816
They can't escape from that water.

0:04:58.840,0:05:00.416
They can't fly.

0:05:00.440,0:05:03.136
And they're accessible.

0:05:03.160,0:05:07.200
You can actually walk up to that pool[br]and you can kill them there, right?

0:05:08.120,0:05:11.736
So the problem that we face with this

0:05:11.760,0:05:15.656
is that, throughout the landscape,[br]all these pools of water with the larvae,

0:05:15.680,0:05:17.656
they are scattered all over the place,

0:05:17.680,0:05:20.896
which makes it very hard[br]for an inspector like this

0:05:20.920,0:05:24.480
to actually find all these breeding sites[br]and treat them with insecticides.

0:05:25.040,0:05:29.240
And last year we thought very, very hard,[br]how can we resolve this problem?

0:05:29.960,0:05:34.416
Until we realized that just like us --[br]we have a unique smell --

0:05:34.440,0:05:37.720
mosquito larvae[br]also have a very unique smell.

0:05:38.480,0:05:40.656
And so we set up another crazy experiment,

0:05:40.680,0:05:43.016
because we collected[br]the smell of these larvae,

0:05:43.040,0:05:46.320
put it on pieces of cloth,[br]and then did something very remarkable.

0:05:46.960,0:05:49.376
Here we have a bar with four holes

0:05:49.400,0:05:52.176
and we put the smell[br]of these larvae in the left hole.

0:05:52.200,0:05:53.416
Oh, that was very quick.

0:05:53.440,0:05:56.576
And then you see the dog.[br]It's called Tweed. It's a border collie.

0:05:56.600,0:05:59.216
He's examining these holes[br]and now he's got it already.

0:05:59.240,0:06:01.576
He's going back to check[br]the control holes again,

0:06:01.600,0:06:03.456
but he's coming back to the first one,

0:06:03.480,0:06:05.296
and now he's locking into that smell,

0:06:05.320,0:06:08.936
which means that now,[br]we can use dogs with these inspectors

0:06:08.960,0:06:12.176
to much better find the breeding sites[br]of mosquitoes in the field,

0:06:12.200,0:06:14.600
and therefore have[br]a much bigger impact on malaria.

0:06:15.320,0:06:16.936
This lady is Ellen van der Zweep.

0:06:16.960,0:06:19.199
She's one of the best[br]dog trainers in the world,

0:06:19.223,0:06:21.263
and she believes[br]that we can do a lot more.

0:06:22.160,0:06:25.616
Since we also know that people[br]that carry malaria parasites

0:06:25.640,0:06:28.496
smell different compared to people[br]that are uninfected,

0:06:28.520,0:06:32.920
she's convinced that we can train dogs[br]to find people that carry the parasite.

0:06:34.800,0:06:38.216
That means that in a population[br]where malaria has gone down all the way

0:06:38.240,0:06:40.656
and there's few people[br]remaining with parasites,

0:06:40.680,0:06:42.416
that the dogs can find these people,

0:06:42.440,0:06:46.336
we can treat them with antimalarial drugs[br]and give the final blow to malaria.

0:06:46.360,0:06:48.640
Man's best friend[br]in the fight against malaria.

0:06:50.080,0:06:52.446
My third story is perhaps[br]even more remarkable ...

0:06:53.280,0:06:56.756
and, I should say, has never been shown[br]to the public until today.

0:06:56.780,0:06:57.781
(Audience cheers)

0:06:57.805,0:06:59.005
Yeah.

0:06:59.760,0:07:04.736
It's a crazy story, but I believe[br]it's perhaps the best and ultimate revenge

0:07:04.760,0:07:05.960
against mosquitoes ever.

0:07:06.440,0:07:07.936
In fact, people have told me

0:07:07.960,0:07:11.440
that now they will enjoy[br]being bitten by mosquitoes.

0:07:12.520,0:07:14.056
And the question of course is,

0:07:14.080,0:07:17.240
what would make someone[br]enjoy being bitten by mosquitoes?

0:07:17.800,0:07:20.120
And the answer I have right here ...

0:07:21.080,0:07:22.522
in my pocket --

0:07:22.546,0:07:23.547
(Laughter)

0:07:23.571,0:07:24.771
if I get it.

0:07:25.960,0:07:27.160
It's a tablet.

0:07:28.000,0:07:29.216
A simple tablet,

0:07:29.240,0:07:31.600
and when I take it with water ...

0:07:32.480,0:07:34.080
it does miracles.

0:07:36.960,0:07:38.240
Thank you.

0:07:44.360,0:07:47.280
Now, let me show you how this works.

0:07:47.960,0:07:50.680
Here in this box, I have a cage

0:07:52.014,0:07:58.992
with several hundred[br]hungry female mosquitoes ...

0:07:59.016,0:08:00.296
(Laughter)

0:08:00.320,0:08:02.776
that I'm just about to release.

0:08:02.800,0:08:04.576
(Laughter)

0:08:04.600,0:08:05.941
Just kidding, just kidding.

0:08:05.965,0:08:07.336
(Laughter)

0:08:07.360,0:08:10.416
What I'm going to show you[br]is, I'm gonna stick my arm into it

0:08:10.440,0:08:12.720
and I will show you[br]how quickly they will bite.

0:08:13.480,0:08:14.680
There we go.

0:08:15.480,0:08:17.671
Don't worry, I do this[br]all the time in the lab.

0:08:18.320,0:08:19.520
There we go.

0:08:20.560,0:08:21.760
OK.

0:08:22.240,0:08:24.240
Now, on the video --

0:08:25.320,0:08:27.136
on the video here,

0:08:27.160,0:08:29.296
I'm going to show you[br]exactly the same thing,

0:08:29.320,0:08:31.456
except that what[br]I'm showing you on the video

0:08:31.480,0:08:34.280
happened one hour after I took the tablet.

0:08:34.799,0:08:36.000
Have a look.

0:08:36.720,0:08:37.936
That doesn't work.

0:08:37.960,0:08:39.159
OK. Sorry about that.

0:08:39.600,0:08:42.576
I'm sticking in my arm,[br]I'm giving them a big juicy blood meal,

0:08:42.600,0:08:45.096
I'm shaking them off,[br]and we follow them through time

0:08:45.120,0:08:47.616
to see these mosquitoes[br]get very, very sick indeed,

0:08:47.640,0:08:49.160
here shown in fast motion.

0:08:49.920,0:08:53.856
And three hours later,[br]what we see at the bottom of the cage

0:08:53.880,0:08:55.080
is dead mosquitoes ...

0:08:56.000,0:08:57.960
very dead mosquitoes.

0:08:58.800,0:09:00.816
And I'm going to say,[br]ladies and gentlemen,

0:09:00.840,0:09:02.840
we have swapped the cards with mosquitoes.

0:09:02.864,0:09:06.416
They don't kill us. We kill them.

0:09:06.440,0:09:13.440
(Applause)

0:09:15.640,0:09:16.840
Now --

0:09:17.960,0:09:21.136
(Laughter)

0:09:21.160,0:09:22.680
Maastricht, be prepared.

0:09:23.400,0:09:25.296
Now, think of what we can do with this.

0:09:25.320,0:09:27.456
We can actually use this[br]to contain outbreaks

0:09:27.480,0:09:30.560
of mosquito-born diseases,[br]of epidemics, right?

0:09:31.160,0:09:33.176
And better still,[br]imagine what would happen

0:09:33.200,0:09:37.400
if, in a very large area, everyone would[br]take these drugs, for just three weeks.

0:09:37.920,0:09:39.536
That would give us an opportunity

0:09:39.560,0:09:41.680
to actually eliminate[br]malaria as a disease.

0:09:42.360,0:09:46.296
So cheese, dogs and a pill[br]to kill mosquitoes.

0:09:46.320,0:09:49.280
That's the kind of out-of-the-box[br]science that I love doing ...

0:09:50.160,0:09:52.136
for the betterment of mankind,

0:09:52.160,0:09:53.776
but especially for her,

0:09:53.800,0:09:57.696
so that she can grow up[br]in a world without malaria.

0:09:57.720,0:09:58.936
Thank you.

0:09:58.960,0:10:00.341
(Applause)