0:00:00.527,0:00:06.981
(Mosquito buzzing)

0:00:10.009,0:00:13.034
(Swat)

0:00:13.034,0:00:16.017
Gotcha.

0:00:16.017,0:00:19.741
Mosquitos. I hate them.

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Don't you?

0:00:21.509,0:00:24.600
That awful buzzing sound at night around your ears

0:00:24.600,0:00:26.971
that drives you absolutely crazy?

0:00:26.971,0:00:29.185
Knowing that she wants to stick a needle in your skin

0:00:29.185,0:00:33.271
and suck out your blood? That's awful, right?

0:00:33.271,0:00:36.652
In fact, there's only one good thing I can think of

0:00:36.652,0:00:39.032
when it gets to mosquitos.

0:00:39.032,0:00:41.743
When they fly into our bedroom at night,

0:00:41.743,0:00:44.848
they prefer to bite my wife.

0:00:44.848,0:00:46.057
But that's fascinating, right?

0:00:46.057,0:00:50.663
Why does she receive more bites than I do?

0:00:50.663,0:00:54.855
And the answer is smell, the smell of her body.

0:00:54.855,0:00:57.505
And since we all smell different and produce chemicals

0:00:57.505,0:01:01.982
on our skin that either attract or repel mosquitos,

0:01:01.982,0:01:05.414
some of us are just more attractive than others.

0:01:05.414,0:01:08.644
So my wife smells nicer than I do, or I just

0:01:08.644,0:01:11.430
stink more than she does.

0:01:11.430,0:01:15.011
Either way, mosquitos find us in the dark

0:01:15.011,0:01:17.746
by sniffing us out. They smell us.

0:01:17.746,0:01:20.456
And during my Ph.D, I wanted to know exactly

0:01:20.456,0:01:23.212
what chemicals from our skin mosquitos used,

0:01:23.212,0:01:26.993
African malarial mosquitos use to track us down at night.

0:01:26.993,0:01:30.561
And there's a whole range of compounds that they do use.

0:01:30.561,0:01:33.588
And this was not going to be an easy task.

0:01:33.588,0:01:36.693
And therefore, we set up various experiments.

0:01:36.693,0:01:39.561
Why did we set up these experiments?

0:01:39.561,0:01:42.914
Because half the world's population runs the risk

0:01:42.914,0:01:46.120
of contracting a killer disease like malaria

0:01:46.120,0:01:48.822
through a simple mosquito bite.

0:01:48.822,0:01:51.189
Every 30 seconds, somewhere on this planet,

0:01:51.189,0:01:54.860
a child dies of malaria, and Paul Levy this morning,

0:01:54.860,0:01:58.707
he was talking about the metaphor of the 727 crashing into the United States.

0:01:58.707,0:02:04.288
Well, in Africa, we have the equivalent of seven jumbo 747s

0:02:04.288,0:02:07.089
crashing every day.

0:02:07.089,0:02:10.330
But perhaps if we can attract these mosquitos to traps,

0:02:10.330,0:02:14.031
bait it with our smell, we may be able to stop transmission

0:02:14.031,0:02:15.861
of disease.

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Now solving this puzzle was not an easy thing,

0:02:18.109,0:02:21.346
because we produce hundreds of different chemicals on the skin,

0:02:21.346,0:02:23.763
but we undertook some remarkable experiments

0:02:23.763,0:02:27.555
that managed us to resolve this puzzle very quickly indeed.

0:02:27.555,0:02:30.918
First, we observed that not all mosquito species

0:02:30.918,0:02:34.766
bite on the same part of the body. Strange.

0:02:34.766,0:02:36.385
So we set up an experiment

0:02:36.385,0:02:39.997
whereby we put a naked volunteer in a large cage,

0:02:39.997,0:02:43.136
and in that cage we released mosquitos

0:02:43.136,0:02:46.455
to see where they were biting on the body of that person.

0:02:46.455,0:02:49.054
And we found some remarkable differences.

0:02:49.054,0:02:51.417
On the left here you see the bites

0:02:51.417,0:02:54.342
by the Dutch malarial mosquito on this person.

0:02:54.342,0:02:57.370
They had a very strong preference for biting on the face.

0:02:57.370,0:02:59.832
In contrast, the African malarial mosquito

0:02:59.832,0:03:05.637
had a very strong preference for biting the ankles and feet of this person,

0:03:05.637,0:03:08.102
and that of course we should have known all along

0:03:08.102,0:03:12.574
because they're called mosqui-toes, you see? (Laughter)

0:03:12.574,0:03:15.681
That's right. (Applause)

0:03:15.681,0:03:21.334
And so we started focusing on the smell of feet,

0:03:21.334,0:03:22.906
on the smell of human feet,

0:03:22.906,0:03:26.608
until we came across a remarkable statement in the literature

0:03:26.608,0:03:30.266
that said that cheese smells after feet

0:03:30.266,0:03:34.348
rather than the reverse. Think of it.

0:03:34.348,0:03:36.607
And this triggered us to do a remarkable experiment.

0:03:36.607,0:03:40.986
We tried, with a tiny little piece of Limburger cheese,

0:03:40.986,0:03:43.658
which smells badly after feet,

0:03:43.658,0:03:46.155
to attract African malaria mosquitos.

0:03:46.155,0:03:48.887
And you know what? It worked.

0:03:48.887,0:03:54.222
In fact, it worked so well that now we have a synthetic mixture

0:03:54.222,0:03:58.736
of the aroma of Limburger cheese that we're using in Tanzania

0:03:58.736,0:04:00.848
and has been shown there to be two to three times

0:04:00.848,0:04:04.730
more attractive to mosquitos than humans.

0:04:04.730,0:04:08.251
Limburg, be proud of your cheese,

0:04:08.251,0:04:11.448
as it is now used in the fight against malaria.

0:04:11.448,0:04:18.244
(Applause)

0:04:18.244,0:04:21.178
That's the cheese, just to show you.

0:04:21.178,0:04:24.357
My second story is remarkable as well.

0:04:24.357,0:04:27.972
It's about man's best friend. It's about dogs.

0:04:27.972,0:04:28.965
And I will show you

0:04:28.965,0:04:32.102
how we can use dogs in the fight against malaria.

0:04:32.102,0:04:35.770
One of the best ways of killing mosquitos

0:04:35.770,0:04:38.725
is not to wait until they fly around like adults

0:04:38.725,0:04:41.812
and bite people and transmit disease.

0:04:41.812,0:04:45.715
It's to kill them when they're still in the water as larvae.

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Why? Because they are just like the CIA.

0:04:50.440,0:04:54.592
In that pool of water, these larvae are concentrated.

0:04:54.592,0:04:57.274
They're all together there. They are immobile.

0:04:57.274,0:05:00.442
They can't escape from that water. They can't fly.

0:05:00.442,0:05:03.899
And they're accessible. You can actually walk up

0:05:03.899,0:05:08.158
to that pool and you can kill them there, right?

0:05:08.158,0:05:12.030
So the problem that we face with this is that,

0:05:12.030,0:05:15.191
throughout the landscape, all these pools of water

0:05:15.191,0:05:17.914
with the larvae, they are scattered all over the place,

0:05:17.914,0:05:20.822
which makes it very hard for an inspector like this

0:05:20.822,0:05:24.800
to actually find all these breeding sites and treat them with insecticides.

0:05:24.800,0:05:27.331
And last year we thought very, very hard,

0:05:27.331,0:05:30.706
how can we resolve this problem? Until we realized

0:05:30.706,0:05:33.969
that just like us, we have a unique smell,

0:05:33.969,0:05:38.480
that mosquito larvae also have a very unique smell.

0:05:38.480,0:05:40.573
And so we set up another crazy experiment,

0:05:40.573,0:05:42.645
because we collected the smell of these larvae,

0:05:42.645,0:05:47.011
put it on pieces of cloth, and then did something very remarkable.

0:05:47.011,0:05:49.404
Here we have a bar with four holes,

0:05:49.404,0:05:52.207
and we put the smell of these larvae in the left hole.

0:05:52.207,0:05:53.282
Ooh, that was very quick.

0:05:53.282,0:05:55.726
And then you see the dog. It's called Tweed. It's a border collie.

0:05:55.726,0:05:58.641
He's examining these holes, and now he's got it already.

0:05:58.641,0:06:01.138
He's going back to check the control holes again,

0:06:01.138,0:06:02.621
but he's coming back to the first one,

0:06:02.621,0:06:05.278
and now he's locking into that smell,

0:06:05.278,0:06:07.508
which means that now we can use dogs

0:06:07.508,0:06:09.836
with these inspectors to much better find

0:06:09.836,0:06:12.220
the breeding sites of mosquitos in the field,

0:06:12.220,0:06:15.089
and therefore have a much bigger impact on malaria.

0:06:15.089,0:06:18.803
This lady is Ellen van der Zweep. She's one of the best dog-trainers in the world,

0:06:18.803,0:06:21.678
and she believes that we can do a lot more.

0:06:21.678,0:06:25.396
Since we also know that people that carry malaria parasites

0:06:25.396,0:06:28.372
smell different compared to people that are uninfected,

0:06:28.372,0:06:30.678
she's convinced that we can train dogs

0:06:30.678,0:06:34.368
to find people that carry the parasite.

0:06:34.368,0:06:36.551
That means that in a population where malaria

0:06:36.551,0:06:40.444
has gone down all the way, and there's few people remaining with parasites,

0:06:40.444,0:06:42.023
that the dogs can find these people,

0:06:42.023,0:06:46.262
we can treat them with anti-malarial drugs, and give the final blow to malaria.

0:06:46.262,0:06:49.770
Man's best friend in the fight against malaria.

0:06:49.770,0:06:52.808
My third story is perhaps even more remarkable,

0:06:52.808,0:06:57.657
and, I should say, has never been shown to the public until today.

0:06:57.657,0:06:59.727
Yeah.

0:06:59.727,0:07:02.933
It's a crazy story, but I believe it's perhaps the best

0:07:02.933,0:07:06.252
and ultimate revenge against mosquitos ever.

0:07:06.252,0:07:09.426
In fact, people have told me that now they will enjoy

0:07:09.426,0:07:12.488
being bitten by mosquitos.

0:07:12.488,0:07:15.196
And the question of course is, what would make someone

0:07:15.196,0:07:17.806
enjoy being bitten by mosquitos?

0:07:17.806,0:07:19.066
And the answer

0:07:19.066,0:07:23.183
I have right here in my pocket,

0:07:23.183,0:07:25.893
if I get it.

0:07:25.893,0:07:29.239
It's a tablet, a simple tablet,

0:07:29.239,0:07:32.121
and when I take it with water,

0:07:32.121,0:07:36.396
it does miracles.

0:07:36.396,0:07:38.069
Thank you.

0:07:40.287,0:07:44.029
(Drinking)

0:07:44.029,0:07:48.045
Now let me show you how this works.

0:07:48.045,0:07:51.062
Here in this box I have a cage

0:07:51.062,0:07:55.856
with several hundred hungry

0:07:55.856,0:08:00.323
female mosquitos

0:08:00.323,0:08:04.211
that I'm just about to release. (Laughter)

0:08:04.211,0:08:07.331
Just kidding, just kidding.

0:08:07.331,0:08:10.223
What I'm going to show you is I'm gonna stick my arm into it

0:08:10.223,0:08:12.938
and I will show you how quickly they will bite.

0:08:12.938,0:08:14.935
Here we go.

0:08:14.935,0:08:18.357
Don't worry, I do this all the time in the lab.

0:08:18.357,0:08:22.159
There we go. Okay.

0:08:22.159,0:08:27.202
Now, on the video, on the video here,

0:08:27.202,0:08:28.570
I'm going to show you exactly the same thing,

0:08:28.570,0:08:31.329
except that what I'm showing you on the video

0:08:31.329,0:08:34.895
happened one hour after I took the tablet.

0:08:34.895,0:08:39.619
Have a look. That doesn't work. Okay. Sorry about that.

0:08:39.619,0:08:42.018
I'm sticking in my arm, I'm giving them a big juicy

0:08:42.018,0:08:44.286
blood meal, I'm shaking them off, and we follow them through time

0:08:44.286,0:08:47.303
to see these mosquitos get very, very sick indeed,

0:08:47.303,0:08:49.462
here shown in fast motion,

0:08:49.462,0:08:52.826
and three hours later what we see at the bottom

0:08:52.826,0:08:55.910
of the cage is dead mosquitos,

0:08:55.910,0:09:00.241
very dead mosquitos, and I'm going to say, ladies and gentlemen,

0:09:00.241,0:09:02.106
we have swapped the cards with mosquitos.

0:09:02.106,0:09:06.826
They don't kill us. We kill them.

0:09:06.826,0:09:14.983
(Applause)

0:09:14.983,0:09:21.067
Now — (Laughter) —

0:09:21.067,0:09:22.905
Maastricht, be prepared.

0:09:22.905,0:09:25.031
Now think of what we can do with this.

0:09:25.031,0:09:27.229
We can actually use this to contain outbreaks

0:09:27.229,0:09:30.615
of mosquito-born diseases, of epidemics, right?

0:09:30.615,0:09:32.632
And better still, imagine what would happen if,

0:09:32.632,0:09:35.691
in a very large area, everyone would take these drugs,

0:09:35.691,0:09:37.952
this drug, for just three weeks.

0:09:37.952,0:09:40.360
That would give us an opportunity to actually eliminate

0:09:40.360,0:09:41.970
malaria as a disease.

0:09:41.970,0:09:46.064
So cheese, dogs and a pill to kill mosquitos.

0:09:46.064,0:09:49.702
That's the kind of out-of-the-box science that I love doing,

0:09:49.702,0:09:52.207
for the betterment of mankind,

0:09:52.207,0:09:55.008
but especially for her, so that she can grow up

0:09:55.008,0:09:59.808
in a world without malaria. Thank you. (Applause)