Cheese dogs and a pill to kill mosquitoes and end malaria Bart Knols

gotcha mosquitoes I hate them don’t you

that awful buzzing sound at night around

your ears that drives me absolutely

crazy knowing that she wants to stick a

needle in your skin and suck out your

blood that’s awful right in fact there’s

only one good thing I can think of when

it gets to mosquitoes when they fly into

our bedroom at night they prefer to bite

my wife but that’s fascinating right

why does she receive more bites than I

do

and the answer is smell the smell of our

body and since we all smell different

and produce chemicals on our skin that

either attract or repel mosquitoes some

of us are just more attractive than

others so my wife smells nicer than I do

or I just stink more than she does

either way either way mosquitoes find us

in the dark by sniffing us out

they smell us and during my PhD I wanted

to know exactly what chemicals from our

skin mosquitoes used African malaria

mosquitoes use to track us down at night

there’s a whole range of compounds that

they do use and this was not going to be

an easy task and therefore we set up

various experiments why did we set up

these experiments because half the

world’s population runs the risk of

contracting a killer disease like

malaria through a simple mosquito bite

every 30 seconds somewhere on this

planet a child dies of malaria and Paula

levy this morning he was talking about

the metaphor of the 77 crashing in the

United States well in Africa we have the

equivalent of seven jumbo 747 crashing

every day

perhaps if we can attract these

mosquitoes to traps bait it with our

smell we may be able to stop

transmission of disease now solving this

puzzle was not an easy thing because we

produced hundreds of difference of

chemicals on the skin but we undertook

some remarkable experiments that managed

us to resolve this puzzle very quickly

indeed first we observed that not all

mosquito species bite on the same part

of the body strange so we set up an

experiment whereby we put a naked

volunteer in a large cage and in that

case we release mosquitoes to see where

they were biting on the body of that

person and we found some remarkable

differences on the left here you see the

bites by the Dutch malaria mosquito on

this person there’s a very strong

preference for biting on the face in

contrast the African malaria mosquito

had a very strong preference for biting

the ankles and feet of this person and

that of course we should have known all

along because they’re called mosquitoes

you see that’s right and so and so we

started focusing on the smell of feet on

the smell of human feet until we came

across a remarkable statement in the

literature that said that cheese smells

after feet rather than the reverse think

of it and this triggered us to do a

remarkable experiment we tried with a

tiny little piece of Limburger cheese

which smells badly after feet to attract

African malaria mosquitoes and you know

what it worked

in fact it worked so well that now we

have a synthetic mixture of the aroma of

Limburger cheese that were using in

Tanzania and has been shown there to be

2 to 3 times more attractive to

mosquitoes than humans Limburg be proud

of your cheese as it is now used in the

fight against malaria

that’s the cheese just to show you my

second story

it’s remarkable as well it’s about man’s

best friend it’s about dogs and I will

show you how we can use dogs and the

fight against malaria one of the best

ways of killing mosquitoes is not to

wait until they fly around like adults

and bite people and transmitted disease

it’s to kill them when they’re still in

the water as larvae why because they’re

just like the CIA in that pool of water

these larvae are concentrated they’re

all together there they are in mobile

they can’t escape from the water they

can’t fly and and they’re accessible you

can actually walk up to that tool and

you can kill them there right so the

problem that we face with this is that

throughout the landscape all these pools

are falta with a larvae they’re

scattered all over the place

which makes it very hard for an

inspector like this to actually find all

these breeding sites and treat them with

insecticides the last year we thought

very very hard how can we resolve this

problem until we realized that just like

us we have unique smell that mosquito

larvae also have a very unique smell and

so we set up another crazy experiment

because we collected the smell of these

larvae put it on pieces of cloth and

then did something very remarkable here

we have a bar with four holes and we put

the smell of these larvae in the left

hole whoo that was very quick and then

you see the dog

it’s called tweet it’s a border collie

he’s examining these holes and now he’s

got it all ready he’s going back to

check the control holes again but he’s

coming back to the first one and now

he’s locking into that smell which means

that now we can use dogs with these

inspectors to much better find the

breeding sites of mosquitoes in the

field and therefore have a much bigger

impact on malaria this lady is Alan from

Goss wave she’s one of the best dog

trainers in the world and she believes

that we can do a lot more since we also

know that people that carry malaria

parasite

smell different compared to people that

are uninfected she’s convinced that we

can train dogs to find people that carry

the parasite that means that in the

population where malaria has gone down

all the way and there’s food few people

remaining with parasites that the dogs

can find these people we can treat them

with anti malarial drugs and give a

final blow to malaria man’s best friend

in the fight against malaria my third

story is perhaps even more remarkable

and I should say has never been shown to

the public until today yeah it’s a crazy

story but I believe it’s perhaps the

best and ultimate revenge against

mosquitoes ever in fact people have told

me that now they will enjoy being bitten

by mosquitoes and the question of course

is what would make someone enjoy being

bitten by mosquitoes and the answer I

have right here in my pocket if I get it

it’s a tongueless simple tablet and when

I take it with water it does miracles

thank you now let me show you how this

works here in this box I have a cage

there’s several hundred hungry female

mosquitoes

that I’m just about to release just

kidding just kidding what I’m going to

show you is I’m gonna stick my arm into

it and I will show you how quickly they

will bite there we go

don’t worry I do this all the time in

the lab there we go okay now on the

video on the video here I’m gonna show

you exactly the same thing except that

what I’m showing you in the video

happened one hour after I took the

tablet have a look that doesn’t work

okay sorry about that I’m sticky getting

my arm I’m giving them a big juicy blunt

meal I’m shaking them off and we follow

them through time to see these mosquitos

get very very sick indeed here shown in

fast motion and three hours later what

we see on the bottom of the cage is dead

mosquitoes very dead mosquitoes and I’m

going to say ladies and gentlemen we

have swapped the cards with mosquitoes

they don’t kill us we kill them

now Maslak vp prayers now think of what

we can do with this we can actually use

this to contain outbreaks of

mosquito-borne diseases of epidemics

right and better still imagine what

would happen if in a very large area

everyone would take this drugs this drug

for just three weeks that would gives an

opportunity to actually eliminate

malaria as a disease so cheese dorks and

a pill to kill mosquitoes that’s the

kind of out-of-the-box science that I

love doing for the betterment of mankind

but especially for her so that she can

grow up in the world without malaria

thank you