How I taught rats to sniff out land mines

At TEDxRotterdam, Bart Weetjens talks about his extraordinary project: training rats to sniff out land mines. He shows clips of his "hero rats" in action, and previews his work's next phase: teaching them to turn up tuberculosis in the lab.

I'm here today to share with you

an extraordinary journey -

extraordinarily rewarding journey,
actually -

which brought me into

training rats

to save human lives

by detecting landmines

and tuberculosis.

As a child, I had two passions.

One was a passion for rodents.

I had all kinds of rats,

mice, hamsters,

gerbils, squirrels.

You name it, I bred it, and I sold them to pet shops.

(Laughter)

I also had a passion for Africa.

Growing up in a multicultural environment,

we had African students in the house,

and I learned about their stories,

so different backgrounds,

dependency on imported know-how,

goods, services,

exuberant cultural diversity.

Africa was truly fascinating for me.

I became an industrial engineer,

engineer in product development,

and I focused on appropriate detection technologies,

actually the first appropriate technologies

for developing countries.

I started working in the industry,

but I wasn't really happy to contribute

to a material consumer society

in a linear, extracting

and manufacturing mode.

I quit my job to focus on the real world problem:

landmines.

We're talking '95 now.

Princess Diana is announcing on TV

that landmines form a structural barrier

to any development, which is really true.

As long as these devices are there,

or there is suspicion of landmines,

you can't really enter into the land.

Actually, there was an appeal worldwide

for new detectors

sustainable in the environments

where they're needed to produce,

which is mainly in the developing world.

We chose rats.

Why would you choose rats?

Because, aren't they vermin?

Well, actually rats are,

in contrary to what most people think about them,

rats are highly sociable creatures.

And actually, our product -- what you see here.

There's a target somewhere here.

You see an operator, a trained African

with his rats in front

who actually are left and right.

There, the animal finds a mine.

It scratches on the soil.

And the animal comes back for a food reward.

Very, very simple.

Very sustainable in this environment.

Here, the animal gets its food reward.

And that's how it works.

Very, very simple.

Now why would you use rats?

Rats have been used since the '50s last century,

in all kinds of experiments.

Rats have more genetic material

allocated to olfaction

than any other mammal species.

They're extremely sensitive to smell.

Moreover, they have the mechanisms to map all these smells

and to communicate about it.

Now how do we communicate with rats?

Well don't talk rat,

but we have a clicker,

a standard method for animal training,

which you see there.

A clicker, which makes a particular sound

with which you can reinforce particular behaviors.

First of all, we associate the click sound with a food reward,

which is smashed banana and peanuts together in a syringe.

Once the animal knows click, food,

click, food, click, food --

so click is food --

we bring it in a cage with a hole,

and actually the animal learns

to stick the nose in the hole

under which a target scent is placed,

and to do that for five seconds --

five seconds, which is long for a rat.

Once the animal knows this, we make the task a bit more difficult.

It learns how to find the target smell

in a cage with several holes, up to 10 holes.

Then the animal learns

to walk on a leash in the open

and find targets.

In the next step, animals learn

to find real mines in real minefields.

They are tested and accredited

according to International Mine Action Standards,

just like dogs have to pass a test.

This consists of 400 square meters.

There's a number of mines

placed blindly,

and the team of trainer and their rat

have to find all the targets.

If the animal does that, it gets a license

as an accredited animal

to be operational in the field --

just like dogs, by the way.

Maybe one slight difference:

we can train rats at a fifth of the price

of training the mining dog.

This is our team in Mozambique:

one Tanzanian trainer,

who transfers the skills

to these three Mozambican fellows.

And you should see the pride in the eyes of these people.

They have a skill,

which makes them much less dependent

on foreign aid.

Moreover, this small team

together with, of course, you need the heavy vehicles

and the manual de-miners to follow-up.

But with this small investment in a rat capacity,

we have demonstrated in Mozambique

that we can reduce the cost-price per square meter

up to 60 percent

of what is currently normal --

two dollars per square meter, we do it at $1.18,

and we can still bring that price down.

Question of scale.

If you can bring in more rats,

we can actually make the output even bigger.

We have a demonstration site in Mozambique.

Eleven African governments

have seen that they can become less dependent

by using this technology.

They have signed the pact for peace

and treaty in the Great Lakes region,

and they endorse hero rats

to clear their common borders of landmines.

But let me bring you to a very different problem.

And there's about 6,000 people last year

that walked on a landmine,

but worldwide last year,

almost 1.9 million died from tuberculosis

as a first cause of infection.

Especially in Africa

where T.B. and HIV are strongly linked,

there is a huge common problem.

Microscopy, the standard WHO procedure,

reaches from 40 to 60 percent reliability.

In Tanzania -- the numbers don't lie --

45 percent of people -- T.B. patients --

get diagnosed with T.B. before they die.

It means that, if you have T.B.,

you have more chance that you won't be detected,

but will just die from T.B. secondary infections and so on.

And if, however,

you are detected very early, diagnosed early,

treatment can start,

and even in HIV-positives, it makes sense.

You can actually cure T.B.,

even in HIV-positives.

So in our common language, Dutch,

the name for T.B.

is "tering,"

which, etymologically,

refers to the smell of tar.

Already the old Chinese

and the Greek, Hippocrates,

have actually published,

documented, that T.B. can be diagnosed

based on the volatiles

exuding from patients.

So what we did is we collected some samples --

just as a way of testing --

from hospitals,

trained rats on them

and see if this works,

and wonder, well,

we can reach 89 percent sensitivity,

86 percent specificity

using multiple rats in a row.

This is how it works,

and really, this is a generic technology.

We're talking now explosives, tuberculosis,

but can you imagine,

you can actually put anything under there.

So how does it work?

You have a cassette with 10 samples.

You put these 10 samples at once in the cage.

An animal only needs two hundredths of a second

to discriminate the scent, so it goes extremely fast.

Here it's already at the third sample.

This is a positive sample.

It gets a click sound and comes for the food reward.

And by doing so, very fast,

we can have like a second-line opinion

to see which patients are positive,

which are negative.

Just as an indication,

whereas a microscopist can process

40 samples in a day,

a rat can process

the same amount of samples

in seven minutes only.

A cage like this --

(Applause)

A cage like this -- provided that you have rats,

and we have now currently

25 tuberculosis rats --

a cage like this, operating throughout the day,

can process 1,680 samples.

Can you imagine the potential offspring applications --

environmental detection

of pollutants in soils,

customs applications,

detection of illicit goods in containers and so on.

But let's stick first to tuberculosis.

I just want to briefly highlight,

the blue rods

are the scores of microscopy only

at the five clinics in Dar es Salaam

on a population of 500,000 people,

where 15,000 reported to get a test done.

Microscopy for 1,800 patients.

And by just presenting the samples once more to the rats

and looping those results back,

we were able to increase case detection rates

by over 30 percent.

Throughout last year,

we've been -- depending on which intervals you take --

we've been consistently

increasing case detection rates

in five hospitals in Dar es Salaam

between 30 and 40 percent.

So this is really considerable.

Knowing that a missed patient by microscopy

infects up to 15 people,

healthy people, per year,

you can be sure

that we have saved lots of lives.

At least our hero rats have saved lots of lives.

The way forward for us

is now to standardize this technology.

And there are simple things

like, for instance, we have a small laser in the sniffer hole

where the animal has to stick for five seconds.

So, to standardize this.

Also, to standardize the pellets,

the food rewards,

and to semi-automate this

in order to replicate this on a much larger scale

and affect the lives of many more people.

To conclude, there are also other applications at the horizon.

Here is a first prototype

of our camera rat,

which is a rat with a rat backpack

with a camera that can go under rubble

to detect for victims

after earthquake and so on.

This is in a prototype stage.

We don't have a working system here yet.

To conclude, I would actually like to say,

you may think this is about rats, these projects,

but in the end it is about people.

It is about empowering vulnerable communities

to tackle difficult, expensive

and dangerous humanitarian detection tasks,

and doing that with a local resource,

plenty available.

So something completely different

is to keep on challenging your perception

about the resources surrounding you,

whether they are environmental,

technological, animal, or human.

And to respectfully harmonize with them

in order to foster a sustainable world.

Thank you very much.

(Applause)