Mar 25, 2014

KILL 'EM ALL

They buzz. They bite. And they have killed more people than cancer, war, or heart disease. Here’s the question: If you could wipe mosquitoes off the face of the planet, would you?

Ever since there have been humans, mosquitoes have been biting us, and we’ve been trying to kill them. And, for the most part, the mosquitoes have been winning. Today there are over 3000 species on pretty much every corner of Earth. Mosquito-borne diseases kill around 1 million people a year (most of them children) and make more than 500 million people sick. But thanks to Hadyn Perry and his team of scientists, that might be about to change. Producer Andy Mills talks with author Sonia Shah about the difficulties of sharing a planet with mosquitoes and with science writer David Quammen about the risks of getting rid of them. 

Oh, and we visit a mosquito factory in eastern Brazil.

And after listening, read this, from Radiolab producer Andy Mills: what if we don't kill 'em all?

Special thanks to reporter David Baker

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Speaker 1:

Hey, wait, you're ...

 

Speaker 2:

Okay.

 

Speaker 1:

All right.

 

Speaker 2:

Okay.

 

Speaker 1:

All right.

 

Speaker 2:

You are ...

 

Speaker 1:

... listening

 

Speaker 2:

... to Radiolab.

 

Speaker 3:

Radiolab.

 

Speaker 4:

Shorts.

 

Speaker 5:

From ...

 

Speaker 6:

WNYC.

 

Speaker 5:

And NPR.

 

Jad Abumrad:

Hey, I'm Jad Abumrad.

 

Robert Krulwich:

I'm Robert Krulwich.

 

Jad Abumrad:

This is Radiolab.

 

Robert Krulwich:

The podcast.

 

Jad Abumrad:

What are we going to do today, Robert?

 

Robert Krulwich:

I think we're going to get rid of something.

 

Jad Abumrad:

And, here to tell us what and why, is producer Andy Mills.

 

Andy Mills:

Okay. So, a while back I was talking with author, Sonia Shaw.

 

Sonia Shaw:

I've had a very fraught relationship with mosquitoes for a long time.

 

Andy Mills:

She actually wrote a book about malaria and mosquitoes ...

 

Sonia Shaw:

Called, The Fever.

 

Andy Mills:

And for her, it all really started when she was a kid.

 

Sonia Shaw:

Well, I grew up visiting India every summer.

 

Andy Mills:

Why were you going to India?

 

Sonia Shaw:

Because my family's from there. All my cousins, all my grandparents, they were all there.

 

Andy Mills:

Summer vacations.

 

Sonia Shaw:

Summer vacations in India with my cousins. All I wanted to do was fit in.

 

Andy Mills:

But the mosquitoes would always call her out.

 

Sonia Shaw:

They knew.

 

Robert Krulwich:

There was a Yankee in the group.

 

Sonia Shaw:

They would just focus on me. And see they wouldn't bite my cousins. They would be totally unscathed and I would be covered in welts. I ended up having to sleep under a mosquito net, which is even more isolating. We used to sleep on little mats on the ground. We would just roll out all these mats on the floor and everyone would sleep in a big long row, except for me. I'd be in a corner under this suffocating net.

 

Andy Mills:

She says at night when mosquitoes would land on her neck, she would think ...

 

Sonia Shaw:

I hate you. I hate you. But at the same time, I'm not allowed to do anything to them.

 

Andy Mills:

And here's when you get to the fraught part. Because Sonia and her family belong to this religion called Jain Dharma.

 

Sonia Shaw:

It's kind of an extreme, non-violent philosophy. You're not supposed to eat meat, obviously. You're not even supposed to eat any root vegetables because then you're killing the whole plant. You're not supposed to walk on grass because if you walk on grass you can kill little insects. When you pray you're supposed to wear a mask so you don't breathe in any microbes or insects and inadvertently kill them. So, I had to act like I'm totally cool with the mosquitoes around me.

 

Andy Mills:

But, every so often ...

 

Jad Abumrad:

Sonia says ...

 

Sonia Shaw:

I would see a mosquito land near me and when I thought no one was looking, I would just sort of mush it with my hand. And I still can feel that tingly feeling on my hand, just telling you that story. That tiny body being crushed by my hand, just, it makes me feel terrible.

 

Andy Mills:

And Sonia's ambivalence toward the mosquito, it has stayed with her her entire life pretty much. Because, on the one hand, she knows that mosquitoes have gotten a bad rap.

 

Sonia Shaw:

First of all ...

 

Andy Mills:

They don't really want to suck your blood.

 

Sonia Shaw:

They don't want to risk their lives to get a blood meal. It's the most dangerous thing they're ever going to do because it's so easy for us to kill them. On top of that, when they fill up with your blood, that blood is several times heavier than their own body weight. So, suddenly, they're full of this stuff and they can't fly very well anymore.

 

Andy Mills:

And on top of that, the only mosquitoes that bite you are the ladies.

 

Sonia Shaw:

And the only reason they do it is because of all the protein and blood, and they use that to nourish their eggs.

 

Andy Mills:

If they didn't have the protein in that blood, nearly all their babies would die.

 

Sonia Shaw:

So they're not even doing it for food.

 

Robert Krulwich:

So every bite is just good mommying, really.

 

Sonia Shaw:

You could say that.

 

Robert Krulwich:

We have to just put out the message that when you're being swarmed by mosquitoes biting you, that you're just being swarmed by good ladies who are just nurturing. That might change the attitude.

 

Andy Mills:

I do not fail to appreciate the charm of the mommy mosquito.

 

Robert Krulwich:

Good.

 

Andy Mills:

But on the other hand, think of all the misery they have caused human beings.

 

Sonia Shaw:

Oh, yeah.

 

Andy Mills:

Like malaria, which mosquitoes spread.

 

Sonia Shaw:

There's good estimates that get bandied around by esteemed experts that one half of all human deaths since the stone age have been due to malaria.

 

Robert Krulwich:

Whoa. One half?

 

Sonia Shaw:

One half of all human deaths since the stone age.

 

Andy Mills:

More people than cancer, more people than heart disease.

 

Sonia Shaw:

So it's had a huge, huge impact on our species. We know this.

 

Andy Mills:

And for me, this is not just some far away, sad, statistical extraction. I used to live and work in Sudan and while I was there, I saw the children's wards at the clinics and hospitals. I saw the kids dying of this disease, all from a mosquito. And where I'm headed with this is, in a world where we are losing animals all the time and we are sad about that, maybe there's this one, the mosquito, that we can actually annihilate. Could this be the creature that we can all agree that we should just get rid of?

 

Robert Krulwich:

You can hope for that Andy, but it's not going to happen because mosquitoes are incredibly fertile. You could make a little groove on a rainy day in the mud and they will have babies in that little patch of water.

 

Jad Abumrad:

It's like a baby party-

 

Robert Krulwich:

Yeah, like a baby party-

 

Jad Abumrad:

... in a footstep.

 

Robert Krulwich:

Exactly. So there is no-

 

Jad Abumrad:

Yeah, you can't-

 

Robert Krulwich:

... way-

 

Jad Abumrad:

... wipe that out-

 

Robert Krulwich:

... you're going to be able to ...

 

Sonia Shaw:

Well, remember, mosquitoes, they reproduce really fast. The typical mosquito only lives for a week or so. So many, many, many generations are evolving as we're throwing chemicals at them. And as soon as one evolves some way to withstand it a little bit better, that little creature sort of sweeps it's genes throughout the population. And that happens within a few years. So three, five, seven years is kind of the time horizon for when you start using a chemical against a mosquito, to when the mosquito population becomes resistant to it.

 

Jad Abumrad:

Wow, well that's a problem.

 

Sonia Shaw:

It's a problem.

 

Andy Mills:

But, but, what if I'd told you that we had gotten to the point where we could solve this problem?

 

Robert Krulwich:

Oh, you'll have to show me an example.

 

Andy Mills:

Oh, that would make me so happy to show you.

 

Andy Mills:

I sent reporter, David Baker, down to this small town in Eastern Brazil to check out this factory.

 

David Baker:

Yeah, this mosquito factory. Just as we come in, a woman with a kind of electrics tennis racket is killing an insect on the wall.

 

Andy Mills:

A mosquito factory?

 

Hayden Perry:

Yeah. It sounds strange, but the world's largest mosquito factory is in Brazil.

 

Andy Mills:

This is Hayden Perry ...

 

Hayden Perry:

Chief executive officer of Oxitec.

 

Andy Mills:

And by factory, he means that this a place where people actually breed mosquitoes, a very special kind.

 

Hayden Perry:

I think at the moment, they're making about four million or so, a week.

 

Andy Mills:

After you pass through a couple of VeriLocks, you enter this massive room.

 

David Baker:

It's a huge concrete warehouse.

 

Andy Mills:

Where there are rows and rows of buckets. How this works is that Hayden and his company in England, they will send the factory workers here a batch of eggs.

 

Aldo Malavasi:

And then we will remove the eggs and put an hour in water. I am Aldo Malavasi, the director of the Medfly and Mosquito Facility in Brazil.

 

David Baker:

And inside ...

 

Andy Mills:

Each of these buckets ...

 

David Baker:

What's that, a gram?

 

Speaker 14:

[inaudible 00:07:26].

 

Aldo Malavasi:

How many? [foreign language 00:07:27].

 

Speaker 14:

[foreign language 00:07:27].

 

David Baker:

And then, inside is 80,000 eggs. And they look like, just tiny, tiny, little black dots.

 

Speaker 14:

[foreign language 00:07:36].

 

Aldo Malavasi:

[foreign language 00:07:38].

 

Aldo Malavasi:

After you put the eggs in about half hour to one hour, they start to hatch. And then we have this mo larvae.

 

David Baker:

Now you can see, this is larva. These are larva, lots of mosquito larva swimming in the water.

 

Andy Mills:

They look like long, translucent worms with spikes all over their bodies.

 

David Baker:

If someone said, "Put your hand in there", I'm not sure if I would.

 

Speaker 4:

It's beautiful.

 

Andy Mills:

Now, according to Hayden, when these mosquitoes grow up and become adults, they will look ...

 

Hayden Perry:

Completely indistinguishable from normal mosquitoes. Except, except that they carry this lethal gene.

 

Andy Mills:

Hayden's company has actually put a tiny, little extra special, extra deadly gene inside their bodies.

 

Speaker 15:

[foreign language 00:08:23]

 

Andy Mills:

Which-

 

David Baker:

So here ...

 

Andy Mills:

... you can actually see. At a certain point in David's trip, one of the factory workers, they brought over this special UV light and they shined it over the larva.

 

David Baker:

Oh, goodness, me. It's like something from Alien. It's like wriggling larva that is full of these globules that are glowing red from inside it's body. Those are the genes that are glowing?

 

Hayden Perry:

Yes.

 

David Baker:

Wow.

 

Andy Mills:

Hayden and his company, they have genetically engineered this glowing, red gene so that when it turns on ...

 

Hayden Perry:

It actually produces a certain protein.

 

Andy Mills:

Inside of these mosquitoes, the gene starts cranking out these proteins more and more, and more and more until the cell basically goes ...

 

Hayden Perry:

Out of control, and the insect dies.

 

Jad Abumrad:

So that means these mosquitoes are going to die?

 

Andy Mills:

No. This is the evil-genius part. They turn off this gene temporarily. Then, in another room in the factory, they hatch the babies, grow the mosquitoes in these test tubes.

 

Hayden Perry:

Thousand parts of these plastic tubes inside of mosquitoes, loads of them.

 

Andy Mills:

Then, they separate ...

 

Speaker 14:

[foreign language 00:09:41].

 

Hayden Perry:

Females and males, okay.

 

Andy Mills:

Then they take just the males ...

 

Hayden Perry:

Put the males into little pots.

 

Andy Mills:

They take the pots out into cities and towns, and every few hundred feet ...

 

Hayden Perry:

They shake these pots out ...

 

Andy Mills:

And release the mosquitoes into the wild.

 

Hayden Perry:

Those males, they go out there, they are just tuned in to finding females.

 

Andy Mills:

Remember, those are the ones that bite.

 

Hayden Perry:

They tune into the wing beat and off they go, find a female, their satisfying their biological urge to mate.

 

Andy Mills:

And the female will go off and lay her eggs. The eggs will hatch, and then, inside each and every one of those little babies, the gene will turn on. They'll start pumping out those proteins, the cell goes out of control.

 

Hayden Perry:

And the larvae will die before they become functioning adults. So, instead of that female laying a hundred eggs at a time, or up to 500 in their lifetime, she lays the same number, but they die.

 

Jad Abumrad:

And they're actually doing this? They've released these mutants into the wild.

 

Andy Mills:

Yes.

 

Hayden Perry:

To give an example of the last trial, they were working in a town called Mandacaru. It's 3,000 people there.

 

Andy Mills:

Mandacaru is this small town in Brazil that's had a really terrible time with the disease that the mosquitoes spread there called Dengue Fever ...

 

Hayden Perry:

Which can make you feel as if your bones are breaking.

 

Andy Mills:

And it can sometimes cause ...

 

Hayden Perry:

Bleeding from the eyes or ears.

 

Andy Mills:

And in kids, death.

 

Andy Mills:

Now they've tried bed nets, they've tried chemicals.

 

Hayden Perry:

They try everything.

 

Andy Mills:

Nothing works. Because in the past decade, what you've seen is cases of Dengue going up and up, and up.

 

Hayden Perry:

Yeah.

 

Andy Mills:

But, in 2011 ...

 

Hayden Perry:

They started releasing our males.

 

Andy Mills:

All across town, they released these mutant males. And then they waited.

 

Hayden Perry:

And within about six months, they reduced the population of the mosquitoes by 96%.

 

Robert Krulwich:

Wow. 96%?

 

Hayden Perry:

Yeah, in that town. So in six months, you've pretty much eliminated the mosquito population.

 

Andy Mills:

And this wasn't just some one-off thing, because the next year, after the rainy season ...

 

Hayden Perry:

Instead of seeing that massive explosion in mosquito numbers, which you get every single year, you didn't see an increase at all. Because there wasn't a population there to build up.

 

Andy Mills:

And this, this is just the beginning.

 

Hayden Perry:

In Brazil, there's been a series of trials ...

 

Andy Mills:

In a bunch of different places.

 

Hayden Perry:

They're all over 90%.

 

Andy Mills:

As in 90% of the population was killed in the first round. And they've released them in different parts of the Cayman Islands.

 

Hayden Perry:

And again, that was the same idea. We had over 90% reduction.

 

Andy Mills:

They're starting their first trials in Panama. They're in talks with local government officials in India, Malaysia and the U.S.A.

 

Sonia Shaw:

Yeah.

 

Andy Mills:

Can we just think about what would the world look like without mosquitoes?

 

Sonia Shaw:

California. There's hardly any mosquitoes there. It would be like California everywhere. That would be totally awesome, right?

 

Jad Abumrad:

Oh, that's going to be my camp slogan, "Kill them all. It will be like California everywhere, Sonia Shaw."

 

Robert Krulwich:

I just want to point out, both of you are acting like the only thing that happens with these animals is they make humans, and particularly human children, sick.

 

Sonia Shaw:

It's not them, it's the parasite.

 

Robert Krulwich:

Right, it's the parasite-

 

Jad Abumrad:

But they're the ones who are spreading it. And so, if our idea is, you stop the mosquito you stop the malaria, then I-

 

Robert Krulwich:

You might stop a-

 

Jad Abumrad:

I've been really-

 

Robert Krulwich:

... few other things, is all I'm saying. Call David, please. Do you know David? Just call David.

 

Andy Mills:

So, we did.

 

Jad Abumrad:

That's a really good mosquito impression, actually.

 

Andy Mills:

Is that David?

 

Robert Krulwich:

That's David.

 

Jad Abumrad:

That's David.

 

Robert Krulwich:

Oh.

 

Andy Mills:

We called David.

 

David Kwahmen:

I'm David Kwahmen. I'm a science writer based in Bozeman, Montana.

 

Jad Abumrad:

He's actually been on this show a bunch.

 

David Kwahmen:

And what I slapped was not a mosquito.

 

Jad Abumrad:

But, the reason that Robert wanted us to call him this time is because, a long, long time ago ...

 

David Kwahmen:

Many, many, many years ago ...

 

Jad Abumrad:

David wrote an article for Outside Magazine ...

 

David Kwahmen:

Titled, Sympathy for the Devil.

 

Jad Abumrad:

That wrestled with the following question.

 

David Kwahmen:

What, if anything, are the redeeming merits of the mosquito? All the harm that they do, all the disease that they cause, these critters have a lot to answer for. But, is that the whole story? Should we therefore, dismiss them?

 

Jad Abumrad:

or destroy them?

 

David Kwahmen:

Or destroy them, or eradicate them?

 

Jad Abumrad:

Did you come up with things to say about this?

 

David Kwahmen:

Well, it wasn't easy, but I did, yeah. I read, read and ...

 

Jad Abumrad:

And while he read, he said he did turn up some interesting facts. For example, there is this mosquito that lives up in the artic ...

 

David Kwahmen:

Aedes Nigripes ...

 

Jad Abumrad:

Which ...

 

David Kwahmen:

Pollinates arctic orchids and spreads no disease to anybody.

 

Jad Abumrad:

Which is nice. But then, David made the following argument.

 

David Kwahmen:

Because of their pestiferous disease vectoring ...

 

Robert Krulwich:

Pestiferous disease vectoring, whoa.

 

David Kwahmen:

They have made a tropical forest very, very difficult for humans to inhabit, to colonize over the last 10,000 years.

 

Andy Mills:

Because every time that we would try and go into those forests, we would get swarmed by mosquitoes and we'd run away.

 

David Kwahmen:

And therefore, they have played an important role in bringing those forests forward relatively intact, into the 21st centuries. The Amazon Forest, The Congo Forest, the forests of Borneo, the forests of Southeast Asia, if there were no difficulties, diseases, threats to the people living in those forests, then those forests would have been turned into settlements, cities, farmlands much more extensively and much earlier than they have been and are now being. I call them nature's Viet Cong, because they are the resistance fighters on behalf of the rain forest.

 

Robert Krulwich:

Why don't we make it harder for you. Why don't we make you imagine that it's springtime or early summer in Alaska, that there's tundra melting everywhere, that there are hordes and hordes, and clouds of mosquitoes. And they are forming a permanent sort of cloud around you. And then Andy Mills comes up and offers you the opportunity to eliminate them completely from the planet. And he makes this offer as they are stabbing you in the wrist, face, cheek and ear.

 

David Kwahmen:

Okay.

 

Robert Krulwich:

You would do what?

 

David Kwahmen:

I would do these two things. First, I would unzip the mosquito net of the tent. And I would say, "Andy, for God's sake, let's have this conversation in the tent." And we would jump in the tent, zip that thing, and then maybe spend about 10 minutes killing every mosquito that got into the tent with us. I admit that.

 

Robert Krulwich:

Okay, that's [crosstalk 00:16:26]-

 

David Kwahmen:

Now, I'd say, "Okay. Now, Andy, we can think about this clearly." And one of the things I'd say was, "Well, look. If we're up here, just two humans in the middle of this Alaskan tundra, and there are these millions and millions of mosquitoes swarming around us to get our blood, obviously we're a small factor on this landscape and they're a big factor, in some way."

 

David Kwahmen:

So, if we were to press a button and eradicate them instantly, it's very difficult to know their load-baring significance in the eco system. Because they're playing lots of different roles as parasites, as competitors, as prey, and ...

 

Andy Mills:

But one of the things that Sonia Shaw told me is that they really don't play a big role in the ecosystem.

 

Sonia Shaw:

I really tried hard when I was writing this book to get a mosquito biologist to explain to me that mosquitoes were useful in their habitats, that they had some ecological role to play that was important. And no one would admit that they had any role at all. They say, "They're not a useful nutrition for bats or fish, or any of the other predators of mosquitoes. Because their biomass is so small that those creatures would be fine without mosquitoes. Everyone would be fine without mosquitoes.

 

David Kwahmen:

She might be right about that. But that's not the only ecological dimension we're talking about. That does not-

 

Andy Mills:

What other dimension-

 

David Kwahmen:

... prove-

 

Andy Mills:

... might there be, just as a for-example?

 

David Kwahmen:

Competition. It might be competing with other insects, and if you eliminate the mosquitoes then suddenly, pheleria flies become much more abundant. When you talk about trying to foresee the consequences of completely eradicating any one species, we just don't know.

 

Robert Krulwich:

The real deep thought here is, if you're going to destroy, the only obligation you owe to yourself is to know what you're killing.

 

David Kwahmen:

Absolutely. And by that, I mean, yes, to know absolutely, the dimensions, the implications of what you're doing.

 

Andy Mills:

And what I'm weighing on here Kwahmen, is that I, too, have been to some of these sub-Saharan parts of Africa. And I just was floored that we have a curable disease, and how many 12, 13, 14-year-old kids were hauled up in this [crosstalk 00:18:54]-

 

David Kwahmen:

Well, I agree with you that that's urgently compelling and important. And I feel the same way that something needs to be done, and that it's true to some extent ...

 

Andy Mills:

In the end, after all the debate, I've ended up at this middle ground.

 

Hayden Perry:

Well, I think what we're aiming to do, actually ...

 

Andy Mills:

Hayden Perry put it to me like this, "We don't have to kill them all everywhere, and in fact maybe we shouldn't, but we can kill them where we live."

 

Hayden Perry:

Eliminate them in our major urban cities and towns where they no longer pose a threat.

 

Andy Mills:

We can draw a line and say, "You know what, you stay out in the woods. We'll stay here." Because the diseases that they're spreading, they will go away if the mosquito goes away for long enough. In America, we don't get malaria hardly ever. Because there's no one with malaria that a mosquito would bite and then give that malaria to someone else.

 

Robert Krulwich:

Oh.

 

Andy Mills:

We have a ton of Anopheles mosquitoes and we have less than a thousand cases of malaria a year. Almost all those cases are somebody like myself, who gets sick in Africa, comes back here. And why is that? Because we hit zero, close to zero, in our cities and towns. Once people stopped having malaria here, mosquitoes stopped getting it and giving it to other people. You just got to hit zero for a while.

 

Sonia Shaw:

Yeah. We just have to kind of place the boundary a little bit better. The mosquito can still do their thing. We can do our thing.

 

Andy Mills:

So, you don't hate them anymore is what you're saying?

 

Sonia Shaw:

I think there's a way to live harmoniously with mosquitoes. I mean, we do it in this country. We have mosquitoes and we control their populations in many ways, but we also get bit.

 

Robert Krulwich:

Special thanks to Andy Mills of course, who learned bug tolerance through Radiolab.

 

Jad Abumrad:

Also a very special thanks to David Baker who went above and beyond in the pursuit of mutant mosquitoes. And thanks also, big thanks, to writer, Sonia Shaw, and to you guys for listening. I'm Jad Abumrad.

 

Robert Krulwich:

I'm Robert Krulwich.

 

Jad Abumrad:

See you next time.

 

Eric:

This is Eric.

 

Rebecca:

And Rebecca

 

Eric:

And we're calling from St. Croix.

 

Rebecca:

In the U.S. Virgin Islands.

 

Eric:

Where we just sailed down from Savannah, Georgia ...

 

Rebecca:

In an 88 year old Grand Banks Dosser fishing schooner.

 

Eric:

Radiolab is supported in part by ...

 

Rebecca:

The National Science Foundation.

 

Eric:

And by the Alfred P. Sloan Foundation.

 

Rebecca:

Enhancing public understanding of science and technology in the modern world.

 

Eric:

For more information about Sloan at ...

 

Rebecca:

Www.sloan.org. 

 

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