Radiolab - KILL 'EM ALL

Episode Date: March 25, 2014

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?

Wait, you're listening. Okay. All right. All right. You're listening to Radio Lab. Radio Lab. Shorts! From W-N-Y-S-C.

See? Yes. And N-P-R. Hey, I'm Chadabum-R. I'm Robert Krollwitch. This is Radio Lab, the podcast. What are we going to do today, Robert? I think we're going to get rid of something.

And here to tell us what and why is producer Andy Mills. Okay, so a while back I was talking with author Sonia Shaw. I've had a very fraught relationship with mosquitoes for a long time. She actually wrote a book about malaria and mosquitoes called The Fever. And for her, it all really started when she was a kid. Well, I grew up visiting India every summer. Why were you going to India? Because my family's from there.

All my cousins, all my grandparents, they were all there. Summer vacations. Summer vacations in India with my cousins. I wanted to do was fit in. But the mosquitoes would always call her out. They knew. There was a Yankee in the group. They would just focus on me.

So they wouldn't bite my cousins. They would be totally unscathed and I would be like covered in welts. I ended up having to sleep under a mosquito net, which is even more kind of isolating, right? Like we used to sleep on little mats on the ground. You know, we would just roll out all these mats on the floor and everyone would sleep like in a big long row. Except for me, I'd be like in a corner under this like suffocating net. She says at night when mosquitoes would land on her net, she would think... I hate you.

I hate you. But at the same time, I'm not allowed to do anything to them. And here's when you get to the frot part, because Sonia and her family belong to this religion called Jane Dharma. It's kind of an extreme nonviolent philosophy. You're not supposed to eat meat, obviously. You're not even supposed to eat any root vegetables, because... 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 prey, you're supposed to wear a mask so you don't breathe in any, like, microbes or insects and inadvertently kill them. So I have to act like I'm totally cool with the mosquitoes around me. But every so often, Sonia says, 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 like that tingly feeling on my hand just telling you that story. That tiny body being crushed by my hand, I mean, it just makes me feel terrible. And Sonia's ambivalence toward the mosquito, it has stayed with her entire life pretty much

because on the one hand, she knows that mosquitoes have gotten a bad rap. First of all, they don't really want to suck your blood. 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. And on top of that, the only mosquitoes that bite you are the ladies. And the only reason they do it is because of all the protein in blood and they use that to nourish their eggs. If they didn't have the protein in that blood, nearly all their babies would die. So they're really only doing, they're not even doing it for food, you know. So every bite is just good mommying, really.

You could say that. We have to just put out the message that when you're being sworn by mosquitoes biting you, that you're just being swung by good ladies who are just nurturing. That might just change the attitude. I do not fail to appreciate the charm of the mommy mosquito. Good.

But on the other hand, think of all the misery they have caused human beings. Oh, yeah. Like with malaria, which mosquitoes spread. There's good estimates that get bandied around by, you know, esteemed experts that one half of all human deaths since the Stone Age have been due to malaria. Whoa. One half of all human deaths since the Stone Age. More people than cancer. More people than heart disease. So it's had a huge, huge impact on our species. We know this.

And for me, this is not just some faraway sad statistical abstraction, right? Like, you know, I used to live and work in Sudan. And while I was there, I saw the children's wards at the clinics and the hospitals. Like, I saw the kids dying of this disease all from a mosquito. And kind of where I'm headed with this is that, like, in a world where we are losing animals all the time and we are sad about that, like, maybe there's this one, the mosquito, that we. can actually annihilate. I mean, could this be the creature that we can all agree that we should just get rid of? 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. It's like a baby party. They're like a baby party. Exactly. So there is no way you're going to be able to. Well, remember, mosquitoes, you know, they reproduce really fast. Yeah, typical mosquito only lives for like 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 its genes throughout the population. And that happens within like 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. Wow. Well, that's a problem. It's a problem. But, but, what if I told you that we had gotten to the point where we could solve this problem?

Oh, you'll have to show me an example. Oh, that would make me so happy to show you. I sent reporter David Baker down to this small town in Eastern Brazil to check out this factory. And here is a mosquito factory. Just as we come in, a woman with a kind of electric's tennis racket is killing an insect. on the wall. A mosquito factory? It sounds strange, but the world's largest mosquito factory is in Brazil.

This is Hayden Perry. Chief Executive Officer of OxyTech. And by factory, he means that this is a place where people actually breed mosquitoes. A very special kind. I think at the moment they're making about $4 million or so a week. Good year. After you pass through a couple of airlocks, you enter this massive room. It's a huge concrete warehouses.

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. And then we remove the eggs and put it in water. I am out of Malabazi director of the Metfly mosquito facility in Brazil. And inside each of these buckets. What's that a gram? How many? How many? 80,000 eggs and they look like they're just tiny tiny little black dots. After you put the eggs in about half hour to one hour, they start to hatch. And then we have a small larvae. And now you can see lots of, this is lava.

These are lava, lots of mosquito larva, swimming in the water. They look like long, translucent worms with spikes all over their bodies. Someone said put your hand in there. I'm not sure if I would. He's beautiful. Now, according to Hayden, when these mosquitoes grow up and become adult, They will look completely indistinguishable from normal mosquitoes, except that they carry this lethal gene.

Hayden's company has actually put a tiny little extra special, extra deadly gene inside their bodies. Which 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 larvae. Oh, goodness me. It's like something from alien.

It's like wiggling lava that is full of these kind of globules that are glowing red, like from inside its body. Those are the genes that are glowing? Yes. Wow. Hayden and his company, they have genetically engineered this glowing red gene, so that when it turns on... It actually produces a certain protein.

Inside of these mosquitoes, the gene starts cranes. ranking out these proteins, more and more and more and more, until the cell basically goes... Out of control. And the insect dies. Does that mean these mosquitoes are going to die? No. This is the evil genius part. They turn off this gene, temporarily.

Then, in another room in the factory... Okay. They hatch the babies, grow the mosquitoes in these test tubes. A thousand, perhaps of these plastic tubes inside. Mosquitoes? Out of them. Then they separate... Fulpea females and males.

Females and males, okay. Then they take just the males. Put the males into little pots. They take the pots out into cities and towns and every few hundred feet. They shake these pots out. And release the mosquitoes into the wild. Those males... They go out there.

They are just tuned in to finding females. Remember, those are the ones that bite. They tune into the wing beat, and off they go. find a female, they're satisfying the biological urge to mate. Then 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. And larvae will die before they become functioning adults. So instead of

that female, laying 100 eggs a time or up to 500 in their lifetime. She lays the same number, but they die. And they're actually doing this? I mean, they've released these mutants into the wild? Um, yes. To give an example of the last trial, they were working in a town called Mandakaru. About 3,000 people there. Mandakaru is this small town in Brazil that's had a really terrible time with the disease

that the mosquitoes spread there called Dengue fever, which can make you feel as if your bones are breaking. And it can sometimes cause... Bleeding from the eyes or ears. And in kids, death. Now, they've tried bed nets, they've tried chemicals. They try everything. Nothing's worked because in the past decade,

what you've seen is cases of dengue going up and up and up. Yeah. But in 2011... They started releasing our males. All across town, they released these mutant males. And then they waited. And within about six months, they reduced the population of the mosquitoes by 96%.

Wow. 96%. Yeah, in that town. So in six months, you've pretty much eliminated the mosquito population. And this wasn't just some one-off thing because the next year, after the rainy season... Instead of seeing that massive explosion of mosquito numbers, which you get every single year, you didn't see any increase at all. Wow. Because there wasn't a population there to build up.

And this is just the beginning. In Brazil, there's been a series of trials... In a bunch of different places. over 90%. As in 90% of the population was killed in the first round. And they've released them in different parts of the Cayman Islands.

And again, that was the same idea. We had over 90% reduction. They're starting their first trials in Panama. They're in talks with local government officials in India, Malaysia, and the USA. Yeah. Can we just think about

what would the world look like without mosquitoes? I mean, California. There's hardly any mosquitoes there. It would be like California. everywhere. That would be totally awesome. Oh, that's my... That's going to be my camp's slogan. Kill them all. It'll be like

California everywhere. Sonia shop. I just want to point out, like you're acting, both of you, are acting like the only thing that happens with these animals is they make humans and particularly human children sick. It's not them. It's the parasite. Right. But they're the ones who are spreading it.

And so if our ideas, you stop the mosquito, you stop the malaria, then I You might stop a few other things, that's all I'm saying. Call David, please, because he, you know David? Just call David. So, we did. That's a really good mosquito impression, actually.

Is that David? That's David. That's David. Oh, we called David. I'm David Quaman. I'm a science writer based in Bozeman, Montana. He's actually been on the show a bunch. And what I slapped was not a mosquito.

But the reason that Robert wanted us to call him this time is because a long, long time ago. Many, many, many years ago. David wrote an article for Outside Magazine. Titled, Sympathy for the Devil. That wrestled with the following question. 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? Or destroy them? Or destroy them, eradicate them. Did you come up with things to say about this? Well, it wasn't easy, but I did, yeah, I read, read, and... And Wally read, he said he did turn up some interesting facts. For example, there is this mosquito that lives up in the Arctic.

It is nigrapes. Which... Pollinates Arctic orchids and spreads no disease to anybody. Which is nice. But then... David made the following argument. Because of their pestiferous disease vectoring... Pestiferous disease vectoring.

Whoa. They have made tropical forest very, very difficult for humans to inhabit, to colonize over the last 10,000 years. Because every time that we would try and go into those forests, we would get sworn by mosquitoes and we'd run away. And therefore, they have played an important role in bringing those forests forward relatively intact into the 20th and 21st centuries. The Amazon forest, the Congo forest, the forests, 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 rainforest. Why don't we make it harder for you? Why don't we make you imagine that it's spring, or early summer in Alaska, that there's tundra melting everywhere, that there are hordes and hordes and clouds of mosquitoes, and they're forming a permanent sort of cloud around you. And then Annie 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. You would do what, say?

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. 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. 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 in 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.

So if we were to press a button and eradicate them instantly, it's very difficult to know their load-bearing significance in the ecosystem because they're playing lots of different roles as parasites, as competitors, as prey. But one of the things that Sonia Shaw told me is that they actually don't play a big role in the ecosystem. I mean, 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,

you know, that they had some sort of ecological role to play that was important. And no one would admit that they had any role at all. They're not a useful nutrition for bats or fish or any of the other, like, predators of mosquitoes because their biomass is so small that, you know, those creatures would be fine without mosquitoes. Like, everyone would be fine without mosquitoes.

She might be right about that, but that's not the only ecological dimension we're talking about. That does not prove. What other dimension might there be as just as a, for example? Competition. They might be competing with other insects. And if you eliminate the mosquitoes, then suddenly Thalaria flies become much more abundant.

I mean, when you talk about trying to foresee the consequences of completely eradicating anyone's species, we just don't know. 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. Absolutely. And by that I mean, yes, to know absolutely the dimensions, the implications of what you're doing. And what I'm weighing on here, Kwanman, is that I, like, 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, like, 12, 13, 14-year-old kids were hauled up in this world, you know? 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 it's true to some extent. In the end, after all the debate, I've ended up at this kind of. middle ground. Well, I think what we'll aim to do, actually. Hayden Perry put it to me like this. We don't have to kill them all everywhere. In fact, maybe we shouldn't. But we can kill them where we live. Eliminate them in our major urban cities and towns, that they no longer pose a threat. 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. Because if we get better, like 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. We have a ton of Anophilis 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. Well, I mean, 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. 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. So you don't hate them anymore is what you're saying. I think there's a way to live harmoniously with the mosquitoes. I mean, we do it in this country, right? I mean, we have mosquitoes, and we control their populations in many ways, but we also get bit.

Special thanks to Andy Mills, of course, who learned bug tolerance through radio lab. 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 Shah. And to you guys for listening, I'm Chad Abram. Ron. I'm Robert Crilwich. See you next time. This is Eric. And Rebecca.

And we're calling from St. Croix. In the U.S. Virgin Islands. where we just sailed down from Savannah, Georgia, in an 88-year-old Grand Banks Gloucester fishing schooner. Radio Lab is supported in part by the National Science Foundation and by the Alfred P. Sloan Foundation. Enhancing public understanding of science and technology in the modern world. More information about Sloan at www.sloan.org.