Should we reengineer the world's deadliest animal?

Summary

Short Wave (NPR)
Episode: Should we reengineer the world's deadliest animal?
Release Date: May 27, 2026
Guests: Ben Bradford (host of “Are We Doomed?” podcast), Dr. Kevin Esvelt (MIT Media Lab biologist)
Hosts: Emily Kwong & Regina Barber

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Episode Overview

This episode explores the revolutionary—and controversial—idea of genetically reengineering mosquitoes, the world’s deadliest animal, to eradicate malaria and other mosquito-borne diseases. Host Emily Kwong is joined by journalist Ben Bradford, who recently reported on the latest gene-editing research and its ethical, ecological, and practical challenges. The episode digs into the science of gene drives, the potentially catastrophic risks of unintended ecological consequences, and the tough ethical questions we face when wielding such power over nature.

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Key Discussion Points & Insights

Why Mosquitoes? (00:31)

• Mosquitoes kill more people than any other animal, spreading diseases like malaria, yellow fever, and dengue.
• The idea: use cutting-edge gene editing (CRISPR) to potentially wipe out disease-spreading mosquitos.
  • Quote: "They are hungry for blood and spreading diseases all the time... But what if we could wipe out the mosquito? We have the technology to do it. But should we?" — Emily Kwong (00:31)

The Promise and Peril of Gene Editing (CRISPR) (03:46)

• Recent gene editing breakthroughs have made it possible to precisely alter the DNA of living organisms.
• CRISPR can be used to engineer a mosquito to always produce male offspring, leading to collapse of malaria-carrying populations.
  • Quote: "With CRISPR, the idea is you can create a mosquito that... always has males, and then its offspring will always have males... and it extinguishes all these species carrying malaria..." — Ben Bradford (04:27)

Why Not Wipe Out All Mosquitoes? (05:01)

• Mosquitoes are important ecologically as pollinators and as food for other animals.
  • Quote: "They're pollinators and birds and spiders... all kinds of critters eat them." — Ben Bradford (05:16)
• The strategy: target only malaria-carrying species in specific regions, sending them on a "sabbatical" rather than eliminating mosquitoes globally.
  • Quote: "We just need them to like disappear for a little while." — Ben Bradford (05:59)

The Jurassic Park Problem: Field Trials & Biosecurity (06:48)

• To test engineered mosquitoes, scientists need isolated field trials, but history warns of unintended releases and lasting consequences.
  • Quote: "Basically what we're describing is a mosquito Jurassic Park... How do you stop what happens in every Jurassic Park movie?" — Ben Bradford (06:50–07:05)

Historical Parallel: Australia & New Zealand's Rabbit Plagues (07:18)

• 19th-century attempts to control rabbit populations led to cascading ecological disasters when new species and diseases were introduced.
• Farmers took drastic, unregulated actions—demonstrates the risk that even well-intentioned containment can fail.
  • Quote: "[Farmers] liquefied the body parts into virus laden smoothies which they spread on their fields. Bam. New Zealand had the rabbit virus." — Ben Bradford (08:42)
  • Quote: "If Jerry gets out, we don't know what harm he would cause because we haven't field tested... Maybe that gene travels throughout all types of mosquito and does eradicate them entirely." — Ben Bradford (09:13)

The "Gene Drive" and Unintended Consequences (10:05)

• Engineered gene drives can rapidly spread a trait through an entire species—and beyond, if hybridization occurs.
• Stakeholders are split between urgency (to prevent millions of deaths) and caution (risking environmental disaster).
  • Quote: "The point is to insert a trait that spreads like wildfire. And wildfire is hard to stop." — Emily Kwong (10:05)

Ethics, Backlash, and the Weight of Action (11:06)

• Technology backfires can poison public trust and set science back by decades:
  • Quote: "A single death in a poorly planned clinical trial set back the entire field by more than a decade. More than a decade is more than 5 million dead children." — Kevin Esvelt (11:06)
• Balancing urgency for disease prevention with restraint and robust testing is a core dilemma.

The Puzzle of Safe Testing (12:05)

• How do you securely test engineered organisms that can fly and breed—with no guarantee of containment?
• The episode highlights the brainstorming and ethical quagmires facing scientists.
  • Quote: "You have to do this sort of like field test, your Jurassic Park. But how do you do the Jurassic park without risking those consequences, where someone's going to steal him or he's going to get out? I mean, they fly, for God's sakes." — Ben Bradford (11:39)

Personal & Public Reactions (12:24)

• Even within the reporting team, the plan strikes some as “insane,” highlighting the deeply personal ethical component beyond just science.
  • Quote: "Someone else on our team... heard it and was like, this is insane. We should never do this." — Ben Bradford (12:24)

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Notable Quotes & Memorable Moments

• "If you can engineer a mosquito so it can't spread disease, you could engineer a mosquito so it always spreads disease." — Dr. Kevin Esvelt (01:41)
• "This is the challenge. And we know what we're trying to avoid because we've seen it in history." — Emily Kwong (07:06)
• "What if birds and spiders and flowers can't adapt to that loss and it creates a domino effect of environmental destruction? Then we've got a problem." — Ben Bradford (09:01)

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Key Timestamps (MM:SS)

• 00:31 Introduction: Why mosquitoes?
• 03:46 How gene editing (CRISPR) works for mosquitoes
• 05:01 Why not eradicate all mosquitoes?
• 06:48 The logistics and risks of field trials ("Mosquito Jurassic Park")
• 07:18 Lessons from Australia and New Zealand's biological misadventures
• 10:05 The wildfire risk: Gene drives and uncontrollable spread
• 11:06 Public backlash, ethics, and responsibility
• 12:05 The unsolved puzzle of safe, effective testing
• 12:24 Team reactions and the reality of ethical discomfort

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Conclusion & Takeaways

• Reengineering mosquitoes via gene drives offers the tantalizing possibility of ending malaria—but carries extraordinary ecological and ethical risks.
• Ensuring safety, securing consent, and maintaining public trust all present daunting, unsolved challenges.
• As Ben Bradford puts it: “The possibilities here are really exciting ... But is the reward worth the risk?” (paraphrased, 12:24)

Listeners are left pondering who gets to decide the fate of a species—and how we balance saving millions of lives with possible catastrophic, irreversible environmental changes.

Transcript

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[Emily Kwong]

listening to Shortwave from NPR. The most ferocious predator for us humans is actually quite small. It's the mosquito. They are hungry for blood and spreading diseases all the time, including serious ones like malaria, yellow fever and dengue. But what if we could wipe out the mosquito? We have the technology to do it. But should we? Here to discuss that is Ben Bradford, the host of a new podcast distributed by the NPR Network. It's called Are We Doomed?

[Ben Bradford]

It is. Hi, Emily.

[Emily Kwong]

So, Ben, your podcast, are We Doomed? Covers a lot, from killer AI to nuclear weapons and of course, the bloodthirsty micro predators. I want to talk about today. How do you feel about mosquitoes, by the way?

[Ben Bradford]

I think they're gross and I think they're rude. And you mentioned Emily, new gene editing techniques could allow us to eradicate our little insect nemesis, potentially saving millions of lives.

[Emily Kwong]

Yes, I learned that from you from your show. Tech is here.

[Ben Bradford]

Yeah. Thank you. And it would be amazing. But also in that technology is something inherently more dangerous. I talked to Kevin Esvelt, who is a biologist now at the MIT Media Lab.

[Kevin Esvelt]

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

[Emily Kwong]

Today on the show, the technology that allows us to kill the mosquito comes with all kinds of complications.

[Ben Bradford]

So 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?

[Emily Kwong]

Easy questions. You know. You're listening to Shortwave, the science podcast from NPR.

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[Emily Kwong]

I'm here with Ben Bradford, who's just done all this reporting on how to save millions of people from malaria by wiping out the mosquitoes. Then how does that even work?

[Ben Bradford]

Yeah. So let's go back to early last decade. Scientists developed a new form of gene editing, which you may know as crispr. It's this way of scalpeling out a tiny strand of DNA, and you kind of like suture in a new trait. It doesn't quite look like that, but that's essentially what's happening.

[Emily Kwong]

Yeah.

[Ben Bradford]

And so with crispr, you can cure a genetic disease or engineer a cow to grow without horns, both things that they have done in labs. But Kevin Esvelt, this biologist now at the MIT Media Lab, had his own realization.

[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 creature do this little DNA surgery. So it always passes along the gene that you put into it. And so with crispr, the idea is you can create a mosquito that, for instance, always has males, and then its offspring will always have males. And so you put it into an area, and it extinguishes all these species carrying malaria in that area because there

[Emily Kwong]

are females to mate with. Yeah, yeah.

[Ben Bradford]

And so to do this, you, of course, have to engineer a mosquito from hell. In the show, we called him Jerry.

[Emily Kwong]

Hi.

[Ben Bradford]

To clarify, Jerry's mission is actually not to murder all mosquitoes because they're just trying to target in an area with malaria. And that's because mosquitoes are ecologically important.

[Emily Kwong]

They are important to the environment.

[Ben Bradford]

I didn't know that, but they are, and it was disappointing. They're pollinators and birds and spiders. Yeah. All kinds of critters eat them.

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Yeah.

[Emily Kwong]

It would be reckless to wipe out mosquitoes entirely. But when it comes to Jerry the mosquito from hell, he's just meant to wipe out the mosquitoes that carry malaria in a certain region. But then the question becomes, how do you do that without affecting Birds and spiders.

[Ben Bradford]

So the idea is to offer birds and spiders a different kind kind of mosquito to snack on. One that doesn't transmit malaria. Because there's a whole bunch of different types of mosquito species. And even better or worse, Kevin says we don't need to take out the malaria carrying mosquitoes forever even.

[Emily Kwong]

Right. You say in the show they just need to, quote, go on a sabbatical.

[Ben Bradford]

Yeah, that's right. We just need them to like disappear for a little while.

[Kevin Esvelt]

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

[Ben Bradford]

So if the mosquitoes go on sabbatical for long enough for the malaria to die out in the humans that the mosquitoes pick up the malaria from and transmit between, then when the mosquitoes come back, the malaria is gone and there's just nothing for them to transmit.

[Emily Kwong]

This plan is bold. It's like use crispr, make mosquito, mosquito. Jerry though, only makes sons. And then the malaria mosquitoes will be wiped out. But not for too long because that would be bad.

[Ben Bradford]

Just enough.

[Emily Kwong]

Just a sabbatical.

[Ben Bradford]

Yeah. And so it turns out that there's a whole bunch of steps that you kind of have to follow if you're going to do this in a you, one, test that the thing actually is going to work and two, test that it's not going to work too well and go around the world and create a whole bunch of problems.

[Emily Kwong]

So how do you even go about testing this?

[Ben Bradford]

Well, you need an area where you're going to put out your mosquitoes into the wild. Kind of a cordoned off area where they're going to be on their own. And basically what we're describing is a mosquito Jurassic Park. And then that leads to other questions, which is how do you stop what happens in every Jurassic park movie?

[Emily Kwong]

The dinosaurs get out.

[Ben Bradford]

And so of course this is the challenge. And we know what we're trying to avoid because we've seen it in history.

[Emily Kwong]

Let's listen to a section of the episode that talks about how this can all go wrong.

[Ben Bradford]

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 on 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's fear. 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.

[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, of mosquito and does eradicate them entirely. What if birds and spiders and flowers can't adapt to that loss and it creates a domino effect of environmental destruction? Then we've got a problem.

[Emily Kwong]

This approach, you know, clearly comes with so many unintended consequences. You say on the show, the point is to insert a trait that spreads like wildfire. And wildfire is hard to stop.

[Ben Bradford]

Yeah. And so that is the main argument against doing this thing, this technology, which is basically called an engineered gene drive. And so there are people who think we should, you know, pack this up, seal it away, never do it.

[Emily Kwong]

And a gene drive in nature is when, like a trait kind of naturally evolves to get passed on.

[Ben Bradford]

It gets really good at being passed through its offspring.

[Emily Kwong]

But here, humans are interfering to make that happen.

[Ben Bradford]

Here we're making it happen. Yeah, yeah, yeah. That's sort of the debate. But of course, the stakes are, do you get rid of malaria? Do you get rid of dengue fever? And so when I talked to Kevin, the person who kind of figured out, hey, we could do this, his biggest concern is that an accidental, untested release of, let's say Jerry, poisons the whole discourse around this in any attempt to do it.

[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. More than a decade is more than 5 million dead children.

[Emily Kwong]

That's a lot of pressure because, you know, mosquito borne diseases cost the lives of hundreds of thousands of people every year. But on the other hand, you don't want to roll out a gene drive project too quickly because something could go terribly wrong.

[Ben Bradford]

And you can hear in our episode that pressure that Kevin feels because of that. And so it does. It creates all of these hurdles, all of these kind of like little puzzles that you need to solve to be able to do that. You know, we need to test our mosquitoes like Jerry, to make sure he doesn't cause unintended consequences. You have to do this sort of like field test, your Jurassic Park. But how do you do the Jurassic park without risking those consequences, where someone's going to steal him or he's going to get out? I mean, they fly, for God's sakes. So like, what are you going to do?

[Emily Kwong]

It is such a puzzle. And in your episode you talk about some ways to work the puzzle to actually, like, take what's theoretical and make it happen in the real world.

[Ben Bradford]

These guys are so smart. They're so smart.

[Emily Kwong]

What is your takeaway from all of this when it comes to the ethics of a gene drive for mosquitoes, but really also for any species?

[Ben Bradford]

Yeah, I think that the possibilities here are really exciting. I mean, malaria is terrible and the mosquito has killed more people than any other creature on the earth. And so you start thinking about how we can solve that for our species. That's amazing. But, you know, I will say, you know, one of someone else on our team, our animator who was watching this episode and doing our animation for it, and he heard it and was like, this is insane. We should never do this.

[Emily Kwong]

Ben Bradford, your podcast are we Doomed? Is out now. Thank you so much. For coming into Shorewave.

[Ben Bradford]

Thank you for having me check out the show.

[Emily Kwong]

It's really good. You can find it all the places you typically get your podcasts. And also, if you haven't already, download the NPR app. My bosses really want you to do it and you will honestly get great journalism from it. Thank you. This episode was produced by Rachel Carlson and edited by our showrunner, Rebecca Ramirez. Tyler Jones checked the facts. Kwesi Lee was the audio engineer. I'm Emily Kwong. Thank you for listening to Short Wave from npr.

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[Emily Kwong]

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[Ben Bradford]

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[Emily Kwong]

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