How Do You Kill a Mosquito?

Summary

Podcast Summary: Are We Doomed? – “How Do You Kill a Mosquito?” (May 12, 2026, NPR Network)

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Overview

In this episode of Are We Doomed?, host Ben Bradford investigates one of humanity’s deadliest enemies—the mosquito—and the radical gene-editing technologies that could potentially eradicate it. Collaborating with MIT biologist Kevin Esvelt, the show delves into CRISPR-driven "gene drives," weighing their immense promise against ethical, ecological, and political risks. The conversation is peppered with compelling history, thought-provoking hypotheticals, and dark scientific humor as the hosts wrestle with not only how to kill the mosquito, but also who gets to make such world-altering decisions.

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Key Discussion Points & Insights

The Mosquito: Humanity’s Greatest Killer

• Mosquitoes, especially those that carry malaria, are responsible for billions of human deaths throughout history.
• "There's a stat...claiming the mosquito has killed as many as half of all humans in history. That is wrong. But it has butchered a lot of us. And it's not done. It's picking up new diseases all the time." (Ben Bradford, 01:10)

Enter CRISPR and Gene Drives (03:00–06:00)

• Gene Drives Explained: Using CRISPR, scientists can ensure a chosen gene is passed to all offspring—turning biology’s usual 50% inheritance rate to 100%.
• Kevin Esvelt describes the method: "If a mosquito has one copy of an engineered chromosome and one original chromosome, the engineered one cuts the original and causes the cell to copy over the engineered DNA." (Kevin Esvelt, 04:39)
• Meet “Jerry”: The show's mascot gene-edited mosquito. The idea is to make Jerry transmit a gene that turns all offspring male or renders females sterile, crashing the population of malarial mosquitoes.

Targeted Eradication, Not Extinction (07:00–09:00)

• The focus isn't on wiping out all mosquitoes, as they play key ecological roles (pollinators, food chain fundamentals), but specifically targeting the malaria vectors.
• “There’s at least a thousand different kinds of mosquitoes in Africa…only a handful transmit malaria.” (Kevin Esvelt, 08:17)
• The strategy is to swap out deadly species for harmless ones, minimizing ecological disruption.

Containment and Testing: The "Mosquito Jurassic Park" Problem (10:00–16:00)

• Real-world trials are necessary to assess efficacy and ecological impact—thus the idea of a "mosquito Jurassic Park," a sealed ecosystem for testing.
• The risk: accidental or deliberate release (illustrated by the story of the rabbit-killing virus being smuggled into New Zealand, 12:21–14:13).
• “If Jerry gets out, we don't know what harm he would cause because we haven't field tested. Consider the possibilities...” (Ben Bradford, 14:35)

Memorable exchange:

“Of course someone would do that. And they would tell themselves a perfect story in which they're the hero, right? Kids are literally dying every moment.” (Kevin Esvelt, 14:28)

Ethical and Societal Risks (15:54–18:34)

• The episode confronts the anxiety about "playing God" and unintended consequences.
• "A lot of people are, to be blunt, really creeped out by the notion that we are engineering nature, our ability to play God. And they quite reasonably doubt whether we are wise enough to deal with that level of power." (Kevin Esvelt, 15:54)
• Esvelt shares his personal struggle after realizing the implications of gene drives, weighing the opportunity to save lives against the risk of global disaster or misuse.

Safeguards: The "Half-Caf" Gene Drive (19:10–20:30)

• Solution: make test gene drives self-limiting—a "half-caf" version whose effects fade after a few generations, reducing risk of unforeseen runaway events.
• “We're doing the limited version. It's not going to spread forever.” (Kevin Esvelt, 19:30)
• Technical explanation: The engineered gene is only active if a second, independently inherited gene is also present, causing the effect to taper off (19:46–20:21).

The Crucial Role of Public Consent and Trust (20:39–24:19)

• Scientific progress depends on trust and clear communication with affected communities.
• The Target Malaria consortium is highlighted for community engagement via education and even theater performances—building local consent before any release.
• "There's this suspicion that they're being used as guinea pigs." (Kevin Esvelt, 21:13)
• Even with success in test communities, achieving universal international consent is complex. National politics and international relations—such as the military coup and foreign alignments in Burkina Faso—can abruptly halt progress.

Regulatory Gaps and Global Risks (25:13–26:37)

• There’s currently no global regulatory framework for gene drives—just patchwork rules varying by organism and country.
• Scenarios range from responsible, hopeful deployment to rogue releases and widespread unintended harm.

Gene Drive Precedents (28:01–30:35)

• The show explores historic analogues, such as the mass release of sterilized screwworm flies to control livestock pests—a less precise but essentially similar technique, used successfully for decades.
• Nature itself creates gene drives: “Nature created gene drives. Difference is that now we can plausibly harness the phenomenon.” (Kevin Esvelt, 30:29)
• Genetic modification, at some level, is not new.

What Else Would You Gene Drive? (30:47–34:33)

• Esvelt’s “top four” candidates for future engineering:
  1. Malarial mosquitoes (already discussed)
  2. Schistosomiasis worms – undermine parasitic infection affecting millions.
  3. New World Screwworm – massive animal and human suffering; could be eradicated and stored (frozen) for safety.
  4. Desert Locust – gene drive to prevent devastating swarms by breaking their biological "switch."
• The science fiction potential—should we also target invasive lanternflies, weeds, rabbits, or restructure whole ecosystems?

Vision vs. Caution (34:33–35:48)

• Esvelt dreams of “rewriting the tapestry of life” for the better, but insists on radical transparency and caution throughout.
• “I envision a world that is kinder and more elegant…” (Kevin Esvelt, 34:59)
• He acknowledges this is a collective choice: "But I'm not the only one who lives here, so I recognize that I need to bring other people along." (Kevin Esvelt, 35:46)

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Notable Quotes & Memorable Moments

• (00:14) Ben Bradford: “The most ferocious killer of us makes even the murderous wild eyed hippo seem like a tiny, glassy-eyed puppy. This creature, it is the mosquito.”
• (02:02) Kevin Esvelt: “Every minute we wait, that’s kids dying.”
• (04:39) Kevin Esvelt: “The engineered [chromosome] cuts the original and causes the cell to copy over the engineered DNA.”
• (08:35) Kevin Esvelt: “No one has yet found any species that seems to care about which mosquitoes it consumes.”
• (13:55) Kevin Esvelt: “[Farmers] smuggled in diced up infected rabbit parts from Australia illegally.”
• (15:54) Kevin Esvelt: “A lot of people are, to be blunt, really creeped out by the notion that we are engineering nature…”
• (16:18) Kevin Esvelt: “Can’t be denied that it’s a lot of power to hand to potentially individuals.”
• (17:41) Kevin Esvelt: “And I think that was still the correct call.”
• (21:13) Kevin Esvelt: “There’s this suspicion that they’re being used as guinea pigs.”
• (25:13) Kevin Esvelt: “The harsh reality is our goal is to get rid of malaria forever. And if one country holds out…there’s a choice to be made.”
• (30:29) Kevin Esvelt: “Nature created gene drives. Difference is that now we can plausibly harness the phenomenon.”
• (34:59) Kevin Esvelt: “I envision a world that is kinder and more elegant…We would reweave the tapestry of life to be more brilliant and beautiful and kind than anything natural selection could ever create.”

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Important Timestamps

• 00:14 — Opening: Humanity as prey and the terror of mosquitoes.
• 03:00 — Gene editing breakthroughs (CRISPR and gene drives).
• 06:35–09:16 — Targeting only malaria-spreading mosquitoes; ecological considerations.
• 10:05–14:28 — The “Mosquito Jurassic Park”; dangers of field trials and accidental release.
• 15:54–18:34 — Ethical dilemmas, existential unease, and decision to move forward.
• 19:30–20:24 — Explanation of "half-caf" (time-limited) gene drives for safe testing.
• 20:39–23:22 — Community engagement: trust, education, and communication.
• 25:13–26:37 — Global risks, regulatory challenges, and hypothetical scenarios.
• 28:01–30:35 — Historical case study: the screwworm fly irradiation campaigns.
• 30:47–34:33 — Gene drive prospects: candidates and unintended consequences.
• 34:59–35:48 — Kevin Esvelt’s vision for a reimagined, gene-driven natural world.

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Conclusion

This episode masterfully blends science, ethics, policy, and storytelling to highlight how close humanity is to wielding world-changing genetic power—potentially defeating malaria, but raising deep questions about ecological dominoes and the limits of human wisdom. Rather than declaring doom, the hosts urge careful, collective decision-making: “How do you kill a mosquito?” doubles as “What kind of species will we choose to be?”

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For further investigation:

• Bonus episode: Kevin Esvelt’s gene drive work on Lyme disease at Martha’s Vineyard
• Support and extras available via doompod.com

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For listeners who missed the episode, this summary provides a comprehensive, timestamped roadmap to the major insights, risks, and scientific drama behind the quest to outsmart our deadliest enemy—the mosquito.

Transcript

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[Ben Bradford]

Humans were prey first, not predators. We were prey. That's why you feel scared in the dark. That's why you feel such rage. When a car cuts you off on the road, you assume attack, not some forgivable mistake. Those are your instincts. Because you and I evolved as prey. And what is the most ferocious killer nature ever developed to feed on? Our kind? Not wolves, though they could surround us in packs and then leap from the dark. Not lions, though they could silently stalk and then leap from the dark. Not even hippos, though they snort and quack and sweat what looks like blood and can charge at you from the dark. Or the day. They don't even care. No, the most ferocious killer of us makes even the murderous wild eyed hippo seem like a tiny glassy eyed puppy. This creature, it is the mosquito. The mosquito with its payloads of deadly diseases. It drops into our bloodstreams. Yellow fever, dengue, especially malaria. It kills and kills and kills. Untold billions of humans have died to mosquito throughout history. 15 million just this century from just malaria. That's like all of Tokyo gone at the hands of one critter. There's a stat that circulates around the Internet claiming the mosquito has killed as many as half of all humans in history. That is wrong. But it has butchered a lot of us. And it's not done. It's picking up new diseases all the time. What if I told you we could wipe out the mosquito? Erase this nemesis from the timeline. We have recently developed the technology. No more bites. Should we do it?

[Kevin Esvelt]

Every minute we wait, that's kids dying.

[Ben Bradford]

Maybe mosquitoes should be asking themselves a certain existential question. This is are we doomed? From nuanced tales distributed by the NPR Network. I'm Ben Bradford and this episode it is Us vs mosquito. New gene editing techniques could allow us to eradicate our little insect nemesis, potentially saving millions of lives. But what does it mean to try to change an entire species? Who gets to decide? What might the ripple effects be? How do you test it? How do you protect it?

[Kevin Esvelt]

If you can engineer a mosquito so it can't spread disease, you could engineer a mosquito so it always spreads disease.

[Ben Bradford]

The technology that allows us to kill the mosquito comes with all kinds of other implications. It could have great upside, but also unforeseeable consequences for not just one little pest, but all life on earth. So our starting question is, how do you use it to take out our greatest killer? Then the next question. Do you think we should do it? So how do you kill a mosquito? Go back to early last decade. Scientists had just had a breakthrough. A new method of gene editing. They'd developed a way to scalpel out a tiny strand of DNA and suture in a new trait. You could cure a genetic disease or engineer a cow to grow without horns. You may know this method as crispr. And Kevin Esvelt, a biologist now at the MIT Media lab, had his own.

[Kevin Esvelt]

Turns out it doesn't just let you engineer organisms in the lab. It lets you let them go. And the engineered trait will spread to most of the ones in the wild. That's incredibly exciting.

[Ben Bradford]

Kevin is the person who figured out you could crispr a creature, so it always passes along the gene you put into it. Maybe his discovery sounds obvious, but it's actually really weird. Like, I'm sorry to bring back memories of middle school biology, but at some point you had to draw punnett squares, these little boxes showing traits like blue eyes and brown eyes and their chances of getting passed along. The point was a gene usually has a 50% chance of inheritance. And Kevin Fish figured out how to use CRISPR to make that 100%.

[Kevin Esvelt]

If a mosquito has one copy of an engineered chromosome and one original chromosome, the engineered one cuts the original and causes the cell to copy over the engineered DNA.

[Ben Bradford]

So it always wins.

[Kevin Esvelt]

Instead of half the offspring inheriting, they all do.

[Ben Bradford]

It's called a gene drive. This is how we're going to kill the mosquito. We're going to cook up our own gene edited mutant mosquito.

[Kevin Esvelt]

So what have we made in the lab? We have made a gene drive. In this case, Mosquito.

[Ben Bradford]

Let's call him Jerry.

[Kevin Esvelt]

Hi.

[Ben Bradford]

And Jerry has some genes we've put in that he's always going to pass down to his kids, ultimately dooming them. So how do you kill a mosquito? With Jerry. Hi. Creating Jerry. A very gross process. Kevin prefers to work on other animals.

[Kevin Esvelt]

The way to most effectively engineer mosquitoes is to let them feed on human blood, which is kind of disgusting, honestly.

[Ben Bradford]

Imagine a sterilized white laboratory with shiny new equipment and reptile cages all around it.

[Kevin Esvelt]

You're talking individual cages or roughly like lizard glass case sized.

[Ben Bradford]

Yeah.

[Kevin Esvelt]

The typical insectary would probably have, oh, 20 or so of those.

[Ben Bradford]

And in those cages you see buzzing and flitting.

[Kevin Esvelt]

And in each of them you'd have several hundred mosquitoes.

[Ben Bradford]

Got it.

[Kevin Esvelt]

You might have in some cases, in bigger Labs, some larger containers, I might say, be room sized populations of mosquitoes with, say, tens of thousands of mosquitoes.

[Ben Bradford]

And Jerry's just in there creating new mutant mosquitoes by breeding with normal, unedited mosquitoes. And you're feeding them blood. Feeding them blood. It is mosquito hell. Forged in the fires of mosquito hell. Jerry emerges. Hi. What have we done to him? What kind of monster is this? What is the gene we put into him going to do when he has kids?

[Kevin Esvelt]

It's either going to turn them all into males or it's going to cause females to eventually be born sterile. Either of these things, of course, reduces the number of mosquitoes in the environment.

[Ben Bradford]

Take option one. We ensure all of Jerry's kids are male. That means when we release our guy into the wild. Not yet. He will meet that special mosquito, someone, and they'll have boys. The boys will grow up. That takes less than a week. And meet other wild mosquitoes who have more boys and so on. Until eventually there are no more female mosquitoes for Jerry's descendants to hook up with in the region. And no more offspring. Bit of upside along the way. Males don't bite. The blood drinking is only done by the females as part of reproduction. They use it in the eggs. Which means that, yeah, every time you get a mosquito bite, it's a sex thing. Now, to clarify, Jerry's mission is not to murder all mosquitoes.

[Kevin Esvelt]

Unfortunately, it's not to get rid of the mosquitoes entirely.

[Ben Bradford]

He's more targeted. Why not murder all mosquitoes? Because they're pollinators and they're food for birds and spiders. They're low on the food chain. We don't know what it would do to everything stacked above. If we rapture them might be a problem. It may be that we need the mosquito. So this leads to a puzzle. How do you kill a mosquito and save millions from malaria? If your ecosystem might rely on these little villains, the answer. Offer the birds and spiders a slightly different mosquito brand to chow on.

[Kevin Esvelt]

There's at least a thousand different kinds of mosquitoes in Africa.

[Ben Bradford]

Only a handful transmit malaria. This is where Jerry comes in. He's taken out mosquitoes only of his own species, the malaria carriers. Then we'll bring in new mosquitoes that still bite. But don't inject us with deadly disease.

[Kevin Esvelt]

And no one has yet found any species that seems to care about which mosquitoes it consumes. Or in the case of plants, is pollinated by.

[Ben Bradford]

You're swapping out cow for bison burgers.

[Kevin Esvelt]

Yeah.

[Ben Bradford]

Yeah, pretty much exactly the most at Risk species could be the vampire spider. A type of jumping spider in Uganda that really prefers the malaria carriers. It finds one who's gorged on our blood, pounces on it, and then bathes in its contents. Were kind of a perfume for them. It's again, creepy crawlies using us and their sex. Don't worry. Scientists think even the vampire spider would adapt.

[Kevin Esvelt]

It's just not a major ecological change.

[Ben Bradford]

Even better or worse, you don't need to permanently take out any mosquito species. We just need a mosquito.

[Kevin Esvelt]

Sabbatical malaria transmission requires humans and it requires mosquitoes. So this is a back and forth transmission chain.

[Ben Bradford]

If the mosquitoes go on sabbatical for long enough for malaria to die out in humans, then when the mosquitoes come back, there's no malaria for them to transmit between humans.

[Kevin Esvelt]

Exactly.

[Ben Bradford]

You guys are smart. Of course, all of this is theoretical. We've only tested Jerry in the lab. We don't know if he works in the wild or if we're right about the ecological effects. You know, gotta protect the vampire spider. So how do you kill a mosquito? The field test.

[Kevin Esvelt]

Does this work outside the lab?

[Ben Bradford]

Kevin says we need to cordon off an area of the real world where we can release a whole bunch of our Jerrys and observe them. We're going to have to build a mosquito Jurassic Park.

[Kevin Esvelt]

We need to find a representative ecosystem everywhere these mosquitoes live. We need a representative ecosystem for each of them. And maybe more than one.

[Ben Bradford]

Picturing kind of like a mosquito. Jurassic Park. Maybe that's not right.

[Kevin Esvelt]

No, that is pretty much right.

[Ben Bradford]

See? But this leads to a problem. What is the problem? Every Jurassic park movie. What happens? The animals escape or someone steals them.

[Kevin Esvelt]

Of course someone would do that if

[Ben Bradford]

Jerry got out early. That could create havoc.

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[Ben Bradford]

How do you kill a mosquito? We're trying to field test our gene edited mutant mosquito Jerry. So we're going to build a mosquito Jurassic Park. But that's challenging. Why? Take a tangent with me. To the shores of Australia and New Zealand in the late 1800s, European ships landed bringing sailors and soldiers and felons and rabbits. Europeans brought rabbits over for food and hunting, snacks and sport. Of course. The rabbits quickly escaped and bred all over both islands and became a scourge on an environment totally unprepared for them. They eat everything. New Zealanders looked to fight back. They brought over ferrets and weasels to sick the rabbits. And when that failed, ferrets and weasels became more invasive species. Skip to the 1990s. Neighboring Australia, largely by accident, unleashed an only partially tested biological weapon against its rabbits.

[Kevin Esvelt]

This nasty virus that wipes out like two thirds of all rabbits or more.

[Ben Bradford]

New Zealand had been considering using this virus as well, but it wanted more testing first.

[Kevin Esvelt]

New Zealand government said we're not sure of safety and so forth. So for now, you're forbidden to import this virus into New Zealand.

[Ben Bradford]

So what do you think happened at this point? New Zealand farmers, losing millions of dollars as rabbits destroyed their crops, began taking little vacations to Australia to go hunting for infected rabbits.

[Kevin Esvelt]

And they smuggled in diced up infected rabbit parts from Australia illegally.

[Ben Bradford]

They liquefied the body parts into virus laden smoothies which they spread on their fields. Bam. New Zealand had the rabbit virus.

[Kevin Esvelt]

And what's the government gonna do when

[Ben Bradford]

it's out, it's out. This is Kevin Sphere. If we do create a mosquito Jurassic park to test Jerry, which we have to do to make sure he works and doesn't cause a ripple effect of unknown ecological destruction, Kevin says some New Zealand farmer is going to steal one of our mosquitoes.

[Kevin Esvelt]

Of course someone would do that. And they would tell themselves a perfect story in which they're the hero, right? Kids are literally dying every moment.

[Ben Bradford]

If Jerry gets Out. We don't know what harm he would cause because we haven't field tested. Consider the possibilities. Jerry and his descendants could travel around the world. These mosquitoes would spawn only males wherever they go, leading to globally extinguishing all of his species. Worse, what if it turns out Jerry can mate with another type of mosquito and he passes along his all boys gene to one of them? What if that one can mate with another species? And so on? Maybe that gene travels throughout all types of mosquito and does eradicate them entirely. What if birds, spiders and flowers can't adapt to that loss and it creates a domino effect of environmental destruction? Then we've got a problem. These are concerns scientists and environmental activists raise about gene drives, sum it up as unintended consequences. It's not just the mosquito. You can game out a similar scenario for any gene drive you try to run on any animal anywhere in the world. The point is to insert a trait that spreads like wildfire. And wildfire is hard to stop. This is the main argument against ever doing a gene drive. This is why some people think we should pack up this technology and seal it away.

[Kevin Esvelt]

A lot of people are, to be blunt, really creeped out by the notion that we are engineering nature, our ability to plague God. And they quite reasonably doubt whether we are wise enough to deal with that level of power.

[Ben Bradford]

Kevin grappled with this question when he first realized you could do do this with crispr, that you could take down the mosquito and a lot more. He felt excited then scared.

[Kevin Esvelt]

Can't be denied that it's a lot of power to hand to potentially individuals. And if you can engineer a mosquito so it can't spread disease, you could engineer a mosquito so it always spreads disease. So that was the realization I woke up to on day two, which cued a minor crisis.

[Ben Bradford]

He struggled with whether he should tell people or bury it.

[Kevin Esvelt]

Is this a problem? Is this technology going to do more net harm than good? Right. If it's net negative, then best it be delayed as long as possible. But it's also true that if it's net positive, then every day of delay is kids dead of malaria.

[Ben Bradford]

So you actually had to make a decision about whether you wanted to present this.

[Kevin Esvelt]

Not even under any illusions that someone else wouldn't do so eventually, yeah, just

[Ben Bradford]

did you want to be the guy? So what did he do? Looked for a book.

[Kevin Esvelt]

And cue my frustration in realizing there is almost no literature on this topic. Turns out people don't write treatises on, hey, have you invented a powerful new technology? Is it Net good or bad? Here's a checklist. There is no such thing.

[Ben Bradford]

Ultimately, Kevin came to this conclusion. Sadly, there are just quicker, more efficient ways to cause widespread biological harm. If that's your goal, we'll consider some of those in future episodes. He figured just gene drives could do really positive things like take out malaria. On balance, he decided it was worth telling people about this technology.

[Kevin Esvelt]

And I think that was still the correct call.

[Ben Bradford]

What have you thought? I've been telling you that we could tweak an entire species DNA or that a mistaken release could circle around the world. Does it seem like a good idea to take out malaria? How about if I told you we could use gene drives to negate the need for toxic pesticides? You could modify insects and weeds so they stay away from our crops. Or does it feel like playing God like every sci fi movie ever and there's just no way? Tampering with creatures DNA doesn't end badly. Kevin wants to convince you and me that gene drives can be safe and good for the world if they're regulated carefully. If they go through through this process. We're discussing how to kill a mosquito.

[Kevin Esvelt]

This is a technology that requires extra safeguards.

[Ben Bradford]

So his biggest concern is an accidental untested release a la Australian rabbits, New Zealand farmers, Jurassic park gone bad. Even if it didn't cause widespread harm, he fears it could scare the world into bans on any gene drive.

[Kevin Esvelt]

We know what happens when there's a backlash to technology. We're seeing it right now for vaccines and other things. And we saw it even in biomedicine with something like gene therapy where a single death in a poorly planned clinical trial that led to tragedy set back the entire field by more than a decade. Yeah, more than a decade is more than 5 million dead children.

[Ben Bradford]

And so all of this brings us back to Jerry. Hi. We need to test him to make sure he doesn't cause unintended consequences. But we can't test him even in our Jurassic park without risking those consequences. How do you solve that riddle? Kevin says easy. Just make Jerry half calf.

[Kevin Esvelt]

We're doing the limited version. It's not going to spread forever.

[Ben Bradford]

He explained earlier that the all boy chromosome we've put into Jerry cuts its rival chromosome so that it never gets passed along. Our gene always wins. How can you make that fade over time?

[Kevin Esvelt]

The simplest way of making sure it doesn't spread forever is you make the cutting dependent on a gene that isn't in the same place so it doesn't get copied over.

[Ben Bradford]

So the always boys Gene only kills its competitor if gene number two is also there. And Jerry's only going to pass gene 2 along half the time. So Jerry's descendants will all be boys because he has gene 2. But only half of them will have it. So their kids will be like 75% boys and their kids will be like 63% boys and so on.

[Kevin Esvelt]

And therefore it's eventually going to die out.

[Ben Bradford]

Ah, that's smart. You guys are smart. So now we finally have a mosquito we can field test without worrying about New Zealand farmers. Next step. How do you kill a mosquito? Public hearings.

[Kevin Esvelt]

We need to find a community of the people who live there and we can make sure that they're okay with it.

[Ben Bradford]

To get local sign off for our Jurassic park, you might think it'd be easy to tell a community. We think we can get rid of your mosquitoes, especially if they're spreading malaria. Be our field test. But it's not. Malaria's densest hotspots are in tropical and subtropical regions of the globe. Often also some of the world's poorest areas. And Kevin says there's an understandable distrust when scientists dive in from other countries.

[Kevin Esvelt]

There's this suspicion that they're being used as guinea pigs.

[Ben Bradford]

There is a catch 22 in using gene drive technology on malaria. First.

[Kevin Esvelt]

The people funding the experiments to make these gene drive mosquitoes are largely the same people that also fund a whole lot of the healthcare of many of the countries suffering from malaria. Which means it's hard for these communities to say actually thanks but no thanks. And most people in malaria afflicted communities, I mean you can imagine more than half a million children dead every single year. And you can just keep going back and back and back. And that just kept happening. And people are people everywhere. It's a tragedy when kids die and they would love to have it stop. The question is, do they trust this as a thing that can stop it and do they trust the people proposing to do this to actually keep their word and tell them the truth?

[Ben Bradford]

How to kill a mosquito is as much a communications issue as it is a scientific one. Maybe more so. The most advanced effort so far to do gene drives against the mosquito this is ongoing is a global consortium of scientists under the name Target Malaria. Kevin's not affiliated with them, but they've generally been following the process we're discussing. Target Malaria has built some versions of Jerry. It operates in the African nations of Uganda and Burkina Faso. And it's had to contend with these trust problems that Kevin's laid out. Target Malaria encountered towns that lacked basic information about malaria. Like that it's spread by mosquito. That's not necessarily intuitive. So what'd the organization do to educate and build support at local community leaders? Suggestion. Staged a play. How do you kill a mosquito? The power of theater. The theater. Let's say all this works. The data looks good. Malaria in the community has gone down. Jerry's not causing unintended consequences. The local populace is happy.

[Kevin Esvelt]

And then is the hard part.

[Ben Bradford]

The hard part. None of this has been the hard part.

[Kevin Esvelt]

The obvious next step is to say, okay, time for the full power version. How do we get everyone living with the relevant mosquito species to agree?

[Ben Bradford]

Because now we're not just talking about releasing half calf Jerry in one test community, we're talking about the full calf. They'll spread everywhere. And mosquitoes don't exactly go through customs, leading to a political conundrum.

[Kevin Esvelt]

What if one country says no?

[Ben Bradford]

Kevin says, you can do all the steps we've talked about. Make our mutant Jerry, make him half calf. Test him in our blood soaked lab, build our Jurassic park, hold public hearings, put on a play, get everything working. All the results looking good. In communities that are happy, you're doing this for them. And you still cannot count on every country giving consent.

[Kevin Esvelt]

We absolutely know that governments will oppose technologies that as best we can tell, would absolutely benefit the people living in the country.

[Ben Bradford]

In Burkina Faso last summer, the project Target Malaria was doing its most advanced work. It had buy in from the community and the government for years. It started field tests. Things were working. Then suddenly the military government raided Target Malaria's facility. Police ordered all the mosquitoes destroyed. They sent a team to spray pesticides into the field test so no data could be gathered from it. Why? It may be as simple as that. The government, which took over in a coup three years ago, is aligning with Russia. It's severing western ties. So no more field tests in Burkina Faso. But Target Malaria research is still advancing in surrounding countries. And what if they want to move forward with a full power gene drive?

[Kevin Esvelt]

The harsh reality is our goal is to get rid of malaria forever. And if one country holds out and just says no, if you do this, I will never cooperate. I will, out of sheer spite, ensure that malaria sticks around in my country so as to thwart you. And you have to keep pouring money and money and money and money into this and you will never achieve your goal. Then there's a choice to be made.

[Ben Bradford]

How do you kill a mosquito? Or rather, who gets to decide the technology? We're discussing is only about a decade old. Countries are playing catch up. A hodgepodge of US Agencies regulate gene drives in this country. It depends on the animal. Some nations have no regulation and there's no widespread international consensus, no UN accord. The potential outcomes for this technology and for its potential against malaria and other diseases is UN in the air. Anything could happen from a rogue scientist releasing a gene drive animal in an unregulated country with worldwide consequences to a global ban. It may sound scary science fiction, except now I have to tell you that we've actually been doing some form of gene drives for decades and we still are just with different technologies and they're really weird foreign.

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[Ben Bradford]

had a favorite solution for any new nuke it, whether it was heating our food with microwaves or carbon dating. They really liked blasting things with radiation, and that included the screwworm fly. It would be hard to find a more vile, cruel animal than the screwworm fly. This little jerk looks a lot like a common house fly, but it does not behave like one.

[Kevin Esvelt]

The screwworm lays its eggs in open wounds, anything as small as a tick bite, and then the maggots. They drill their way into the healthy flesh, cause excruciating agony.

[Ben Bradford]

They screw themselves in, and then they only get more vicious, explains our mit Biologist Kevin Esvelt.

[Kevin Esvelt]

And it opens separating wounds that then draw in new screwworm flies. And so the animal gradually gets devoured alive in this macabre symphony of death.

[Ben Bradford]

Horrifying.

[Kevin Esvelt]

It's gruesome and it's agonizing. And we know this because it happens to people.

[Ben Bradford]

Yeah.

[Kevin Esvelt]

The standard treatment is you give the patient morphine while the doctors cut out the larva.

[Ben Bradford]

In the mid 20th century Americas, screwworm flies devastated livestock and occasionally humans. Some atomic age scientists thought nukem. They figured out that blasting male screwworms with the right amount of radiation might would not kill them, but would make them sterile. Since screwworms only mate once, if you released your sterilized radiation blasted insects during screwworm mating season, then the sterile ones

[Kevin Esvelt]

will mate with the wild ones because it'll be in great excess. And then the wild ones won't have any offspring and the population will crash.

[Ben Bradford]

The US tried this, began releasing millions of sterile screwworm flies without any of the precautions we've been talking about for the mosquito and our guy Jerry. And it worked.

[Kevin Esvelt]

They started in Florida, pushed them west, then down through Texas.

[Ben Bradford]

We pushed the screwworm back through Mexico, through Central America, down to the southern tip of Panama where they remain and where we're still doing this.

[Kevin Esvelt]

On average, 10 million irradiation sterilized screw worm flies every week to maintain a living wall preventing the screw worm in South America from re invading the North.

[Ben Bradford]

Irradiating screwworms isn't technically a gene drive. Different technology. But it is effectively the same thing as we're talking about with mosquitoes. Right. The point is, it's not a new idea. Nor is genetic modification. Pet a dog sometime, even gene drives ensuring one set of DNA always gets passed along. Those do occur in the wild.

[Kevin Esvelt]

Nature created gene drives. Difference is that now we can plausibly harness the phenomenon.

[Ben Bradford]

We've talked about what it would mean to take on our greatest butcher, the mosquito. What about other species? What else could we plausibly go after with a gene drive? I asked Kevin for his pitch.

[Kevin Esvelt]

What species merit engineering. The whole species.

[Ben Bradford]

Yeah.

[Kevin Esvelt]

I think there's a good case for four.

[Ben Bradford]

Four species that are top candidates. He'd like to see get their own jerrys.

[Kevin Esvelt]

Number one, Malarial mosquitoes.

[Ben Bradford]

We already talked about it.

[Kevin Esvelt]

Two, Schistosomiasis. Horrific parasitic worms. Causes growth and cognitive stunting in children.

[Ben Bradford]

These are flatworms, also called blood flukes. They crawl into people bathing or swimming in water and lay eggs inside of them. The worms can live for as long as 30 years, and the average infected person has hundreds inside of them.

[Kevin Esvelt]

More people suffer from it than malaria tends to be in the same areas. If things work well with malaria, it's an obvious next target. Species number three, the new world screwworm. Probably the greatest source of animal suffering in the world. If integr time.

[Ben Bradford]

The ones we're currently blasting with radiation down in Panama. Except a couple years ago they broke through our radioactive flywall.

[Kevin Esvelt]

They've begun creeping up and now they're reinvading. And now they're not that far from the Texas border. Although not in high densities yet we

[Ben Bradford]

know the suffering it causes to animals. And it's continued to be bad for humans too. Below the wall. And Kevin says you could wipe out every screwworm in the wild and always reverse it.

[Kevin Esvelt]

Screw them is one of the very few species where you can freeze the larvae pretty much indefinitely. So we can literally remove them from the wild and keep the species on ice, not extinct, in case there was a problem.

[Ben Bradford]

And then.

[Kevin Esvelt]

Yeah, in case there's a problem. When are you going to bring them back?

[Ben Bradford]

Yeah, yeah, yeah. Or ultimately destroy them if there's not a problem? Because I've seen sci fi movies before and every time you freeze something for the future it gets unfrozen. And that's a problem.

[Kevin Esvelt]

Yeah. Tell that to the people currently keeping frozen samples of smallpox.

[Ben Bradford]

Species number four Kevin would go after with a gene drive.

[Kevin Esvelt]

The desert locust. God's eighth biblical plague causes horrific famines throughout history. Why is this a good target? Because the locust is most of the time a harmless desert grasshopper.

[Ben Bradford]

The locust is ridiculous. Deep, deep in its DNA, it has a trigger. When certain rare conditions are met, it changes from harmless to monster.

[Kevin Esvelt]

When it rains enough in the desert, then they multiply, multiply, multiply. Then they're massively overpopulated. And the sheer proximity of all these locusts causes them to undergo this epigenetic change. They change color. They switch from being solitary and avoiding each other to being gregarious and swarming. And then they all come together in this enormous mass and fly out of the desert in a swarm of locusts.

[Ben Bradford]

The biblical plague leg. One swarm can eat as much as all of paras. Kevin says we know the environment doesn't need locust swarms because whole regions go decades without them. Andy says you don't even need to wipe them out with a gene drive.

[Kevin Esvelt]

We could just gene drive them to break the switch.

[Ben Bradford]

Just remove that one DNA trigger so they always stay simple grasshoppers. So those are four species Four disgusting little creatures, creatures that cause widespread harm. I think Kevin makes a compelling case. But then do you stop or would you gene drive more? Would you root out the invasive weeds that contribute to California's raging wildfires? How about the absolutely disgusting invasive lanternflies that New Yorkers have been deputized to kill but are sweeping their way west anyway because you failed New York? What about engineering weeds so they avoid farmland, meaning less pesticides? What about the rabbits of New Zealand? And where does it end? The possibilities are huge and daunting. I asked Kevin about his vision for this technology. He was the first to tell the world about.

[Kevin Esvelt]

Well, here's time for a confession.

[Ben Bradford]

Okay, let's go.

[Kevin Esvelt]

I am simultaneously the foremost advocate for transparency and extreme safeguards and the one who wants to completely rewrite the tapestry of life.

[Ben Bradford]

Kevin wants to change all of the above. Everything. He says, when we rely only on natural selection, we get blood flukes and locust swarms. So why not tamper? Carefully but broadly.

[Kevin Esvelt]

I envision a world that is kinder and more elegant. One where instead of spraying our fields with insecticides to kill the insects so they don't eat our crops, we instead engineer them to not like the taste and otherwise go about their normal ecological role, where we can create new diversity, new forms of life to solve problems that we're experiencing or that other organisms are experiencing. We would reweave the tapestry of life to be more brilliant and beautiful and kind than anything natural selection could ever create. But I'm not the only one who lives here, so I recognize that I need to bring other people along.

[Ben Bradford]

Gene drives could save an untold number of lives or change the world in ways that are hard to comprehend. Or both. Building Jerry to take out the mosquito would be a first step, a proof of concept. It could show how scientists can modify species safely, transparently, with public hearings and stage plays and Jurassic Parks. It could also open the door to a world where gene drives feel ordinary, ubiquitous. All of which means, how do you kill a mosquito? Maybe by deciding what kind of species we're going to be. So you heard the ethical concerns. You heard Kevin's worries about pushing this technology onto people who feel they have no say in the matter. And so hear why. Kevin, who worries so much about malaria, is not starting with mosquitoes himself. He's working on Lyme disease on Martha's Vineyard. That's a bonus episode available for [e-mail] It'll be out next week, our second bonus episode. We have all kinds of other extras. They're thank yous for helping us to keep doing this show. And I'll just say thank you to everyone who's already become a [e-mail] support next week on Are We Doomed?

[Kevin Esvelt]

It's not like a blinding light or, you know, it's not a post apocalyptic Mad Max thing.

[Ben Bradford]

More people than you think would survive nuclear war, so buckle up and you're

[Kevin Esvelt]

just like, this is the worst Porta Potty you can imagine.

[Ben Bradford]

Are We Doomed Is a production of nuanced tales. Our producer is Lindsey Kilbride. Our editor is Tracy Samuelson, engineer and sound designer Jay Sebold. Our fully animated YouTube episodes at YouTube.com We DoomedPod are by Alboris Kamalasad. Theme music composed by Dylan Dagenet. The show is distributed by the NPR network. Big thanks to Dan McCoy, Kalia Ali and the rest of the team at NPR for all they do. And most of all, again, thank you for listening and supporting us.

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