Throughline - Buzzkill

Episode Date: April 16, 2020

In the whole of human history, no predator has killed more of us than the lowly mosquito. And this killing spree, which we still struggle in vain to stop, means the mosquito has been an outsized force in our history — from altering the fate of empires to changing our DNA. This week, three stories of the quiet legacy and the potential future of the mosquito.Learn more about sponsor message choices: podcastchoices.com/adchoicesNPR Privacy Policy

Support for this podcast and the following message come from Autograph Collection Hotels, with over 300 independent hotels around the world, each exactly like nothing else. Autograph Collection is part of the Marriott Bonvoy portfolio of hotel brands. Find the unforgettable at AutographCollection.com. We like to think we get to make our own history, that we did this as human beings. And that's not necessarily the case. We have to look back at history and take away some of the human elements

to look at what is really going on. And it is mosquito-borne disease that is the game-changer or decides the fate of these certain historical events, not human agency. We seem to be fighting a losing battle throughout our existence. It's still the animal that kills more human beings on the planet than any other animal to this day, and that's including other humans.

You're listening to ThruLine from NPR. Where we go back in time to understand the present. Hello. Hi, is this Omar? Hi. Yes, hi. This is Rund. I'm one of the hosts of the show. And I think Rund's team...

Hi, hello. Hey. Hey. Awesome. Technology. It's amazing how much we've been able to continue doing this show, despite the fact that we're all in isolation. It's probably safe to say that, right now, you're not thinking much about mosquitoes. With all the coronavirus talk going on at NIDA, safe to say that right now, you're not thinking much about mosquitoes.

With all the coronavirus talk going on right now, I thought you guys would focus mostly on coronavirus, but mosquitoes are just as important, I would argue. This is Omar Akbari. He's an associate professor at the University of California, San Diego. And he spends a lot of time studying mosquitoes in his lab. One thing to think about with coronavirus is that you can actually socially distance yourself and protect yourself, right? But with mosquito-infected pathogens, how are you going to isolate yourself? How are you going to protect yourself? It's difficult, right?

Omar says mosquitoes are without a doubt humanity's greatest predator, past and present. You know, as of right now, just thinking about malaria, there's about a thousand people dying every single day, and those are mostly children under the age of five. And if you calculate it, it's a child dying every two minutes, right? And dengue fever, you get about 390 million infections. And those mosquitoes that are transmitting those pathogens are becoming more abundant, and they're spreading to new places

because of climate change and global warming. New places like, for example, California. In California, which is where I live, prior to 2013, there were no Aedes aegypti or Aedes albopictus mosquitoes. And those are the kinds of mosquitoes that transmit dengue, Zika, yellow fever, chikungunya. They're nasty mosquitoes. And they weren't in California prior to 2013, but in seven years they spread throughout all of California and they're going to continue to populate the United States.

And we're just going to continue to see this happen over and over again. Omar is part of a community of scientists from all over the world trying to come up with a plan to fight the mosquito before things get worse. Now, this might seem like an impossible task, right? Battling millions upon millions of mosquitoes across the globe. But consider this. Most mosquitoes are completely harmless. There's over 3,000 species of mosquitoes on Earth,

but only a handful of them actually transmit pathogens that affect us. Those few outliers, the ones that transmit pathogens, the ones that can kill, those are the mosquitoes Omar and other researchers care about. Their goal is to find ways to prevent those mosquitoes from passing on deadly viruses. And really, these consist of what I would call population replacement or population suppression. Let's break that down really quickly. So population replacement means scientists modify the genetic code of mosquitoes so they can no longer transmit deadly diseases, in effect overriding natural selection and choosing which genes are passed on.

Population suppression takes an even more extreme approach. The goal with that is to get rid of those species that transmit these pathogens, right, completely from population. In other words, eliminate the deadly mosquitoes altogether. Now, that's a little more complicated because whenever you totally get rid of something in the wild, it can disrupt the ecosystem. So far, Omar and others have only had success in the lab. In our lab, we have actually engineered mosquitoes that are unable to transmit dengue virus and

Zika virus. And there are other groups that have engineered mosquitoes that cannot transmit the malaria parasite. So we know we can engineer mosquitoes that are unable to transmit pathogens. The next step is figuring out how to get those engineered mosquitoes into the real world. And the biggest challenge there is speed. Viruses adapt fast, so they need to make sure that the mosquitoes can spread these modified genes across the wild population before the viruses evolve and make those genes obsolete. While scientists are making progress every day, the pressing question is, will they solve this puzzle fast enough? It's a race against time. It's a race against evolution. These viruses are rapidly evolving in the wild. It's just a matter of time

before the next Zika-type virus, you know, comes onto the radar. So we need to develop better technologies now to protect ourselves in the future, just like we need to do for coronaviruses. Mosquitoes were on Earth long before humans arrived and have played an outsized role in our history from the start. This tiny insect has tipped the scales in crucial battles,

changed the fate of empires, and even altered our DNA. In total, mosquitoes are thought to have killed roughly half of all humans who have ever lived. That's an estimated 52 billion people. So on this episode, we're going to focus on three stories. Stories that will remind us how much of human history was shaped by something out of our control. Something so small, yet so deadly. And give us a clue about how it might shape our future.

This is Tish Thomas and Rick Pinnell chasing cattle around the pasture in Rushville, Missouri. And we love to listen to ThruLine. and spend or receive money internationally, and always get the real-time mid-market exchange rate with no hidden fees. Download the Wise app today or visit wise.com. T's and C's apply. The pontine creates fear and horror. Before entering it, you cover your neck and face well before the swarms of large, blood-sucking insects are waiting for you in this great heat of summer. Between the shade of the leaves, like animals thinking intently about their prey. Here you find a green zone, putrid, nauseating, where thousands of insects move around, where thousands of horrible marsh plants grow under a suffocating sun. The Pontine Marshes are roughly 310 square miles of marshland just east of Rome.

Essentially throughout history, they were one of the malarial hotbeds of Europe. In fact, Europeans generally call malaria the Roman fever. Ancient scribes recorded the symptoms of this Roman fever. So it's a very cyclical time frame of when you get chills, fever, sweat, feel fine. And starts all over again. Chills, fever, sweat. You're stuck in bed. Feel fine. Alternating between pain.

Chills, fever, sweat. And relief. Feel fine. But eventually you get what they call cerebral malaria, which is essentially swelling of the brain, and then you go into a coma and you die. I'm Dr. Tim Weingart. I'm a history professor at Colorado Mason University,

also the head coach of the hockey team, being Canadian, and I wrote the book, The Mosquito, A Human History of Our Deadliest Predator. It was the year 264 BC, in ancient Rome. The Roman Republic had by then conquered the Italian peninsula and expanded throughout the Mediterranean, just beginning their rise to power. But this also meant that the Republic was in a state of constant warfare

as they fended off sieges from neighboring enemies. They were able to maintain their stronghold in part thanks to the Pontine marshlands that surrounded the city. After the fall of Alexander the Great's empire, there's two vying superpowers, if you will, who are vying to control trade in the Mediterranean region, and that's Carthage and Rome. Carthage was an ancient city in North Africa in what's today called Tunisia. It was one of the wealthiest and most advanced cities in the Mediterranean. It had a navy that could actually threaten Rome.

And eventually they're going to butt heads to control trade. And one way to control trade was to wage war. Why trade when you can invade, right? This began more than a century of conflicts between the two powers, which came to be known as the Punic Wars. The First Punic War lasted 23 years, ending with a devastating defeat for the Carthaginians. Legend has it, after the loss, one of Carthage's generals went home humiliated and did something that would change the future for his city. He made his son, his heir, dip his hands in blood and swear an oath of hatred against Rome.

That child would grow up to be called Hannibal of Carthage. When he became a military commander, Hannibal began a campaign to avenge the loss of the First Punic War. He marched his army across the Pyrenees and the Alps. So he comes into Italy and he defeats the Romans battle after battle after battle. Hannibal's march towards Rome culminated in the epic Battle of Cannae. And at the Battle of Cannae, he absolutely annihilates the Roman legions. After that battle, the doorstep to Rome is wide open for Hannibal to essentially attack the Eternal City, take Rome, and end the Punic Wars. But he doesn't. Hannibal stopped his invasion of Rome. One of the main reasons?

The Pontine Marshes. In order to lay siege to Rome, you cement yourself in these Pontine Marshes. And Hannibal was already very familiar with malaria. In fact, he lost his right eye to the fevers of malaria. His troops had contracted malaria in northern Italy. His wife and son had already died of malaria. It might seem a little harsh to say this, but it's important to note that a sick soldier is more draining on the military machine than a dead one.

Dead soldiers need to be replaced in the line, no question. But a sick soldier also needs to be replaced in the line, but they also continue to consume valuable resources. So they're actually a drain on the military machine and they're a handicap. So he wasn't willing to sacrifice his army essentially to the malarious mosquitoes of the Pontine marshes. With that, Hannibal's campaign for Rome came to an end. And century after century, those mosquitoes in the marshes held off invader after invader. The Pontine marshes were like a biological moat that protected Rome. But mosquitoes don't favor sides in war.

They infect without prejudice. And Rome itself fell victim. Endemic malaria starts to suck and bleed the vitality of Rome because everybody's sick all the time. You don't have enough farmers to farm your crops. You don't have enough farmers to work in the mines. You don't have enough traders. So your society starts to collapse upon itself because your manpower is continuously rotating through sickbay, if you will. So that's when people came up with the obvious solution. Drain it.

In 300 B.C., this land had been a fever-stricken swamp. All efforts to cultivate it had failed. Nero, the Caesars, the Popes, even Napoleon I... For centuries, people tried and failed. And it wasn't until the early 20th century that someone finally managed to do it. The triumph of Mussolini. So eventually Mussolini successfully reclaims these Pontine Marshes. The Battle for Land was a project started in 1928 by Benito Mussolini, Italy's fascist dictator.

His goal was to turn the marshes into farmland. ...been constructed to carry away the waters which will leave a fertile land of over 200,000 acres. He builds pumping stations, canals to drain the water out into the sea. Thousands of tons of chemicals are being thrown down to destroy the eggs of mosquitoes before the sowing begins. He plants a bunch of trees, like tons of trees, relocates people into this new reclaimed land. They start farming. He builds a bunch of model towns,

makes sure they have screens on all the windows, and there's mosquito precautions in these model towns, if you will, as well. And malaria rates across Italy are slashed by over 90%. So it's actually a remarkable feat what Mussolini does. Benito Mussolini, who had been dictator of the Italian people for 21 uninterrupted years, fell from power. After Benito Mussolini was deposed by his own citizens during World War II,

Italy signed an armistice with the Allied powers. Hitler was enraged that the Italians had switched sides. And eventually, the Allies decided to land at the Italian port of Anzio, where they'd try and stomp out the Axis presence in the country. The first military surprise blow in the Italian stalemate comes in a bold, large-scale landing on the Nazi hill coast near Anzio. Hardly a soldier gets ashore without trial by fire. The objective was to take Rome. Not in a week or a month. The Allies are going to outflank the German line in Italy and land behind the German line with landings at Anzio to march on Rome. So at that point, the Nazis decided to consult their experts on malaria.

Here the retreating Germans dug in. Every bridge was blown. And so what the Nazis do is reverse the draining pumps to actually suck water back in, destroy the canals, destroy the dikes, cut down trees to turn it back into essentially just a quagmire, a nasty marshland again, and reflood the Pontine Marshes to reintroduce malaria to Naples and Anzio to slow down the Allied advance. And it did some serious damage. Over 40,000 Allied troops contract malaria, including my wife's grandfather, who was at Anzio and contracted this pontine biological weaponry malaria. And he says it was, you know, just absolutely horrible and that the mosquitoes at Anzio were worse than the German shelling,

is what he told me. And so it's a deliberate act of premeditated biological warfare conducted by the Nazis at Anzio. Malaria has been used as a weapon of war for millennia, but it's also sparked a fierce battle within our own bodies. Coming up, how a genetic mutation that's been passed down for thousands of years led an early society in Africa to conquer neighbors in its region. And how that exact same mutation still impacts people today. Hello, my name is Fusola Urijebi from Lagos, Nigeria, and you're listening to True Life from NPR. I love True Life. It $1.75 million to support NPR programming.

Whether buying a few bottles or joining the club, you can learn more at nprwineclub.org slash podcast. Must be 21 or older to purchase. On October 21st, 2007, the Pittsburgh Steelers were playing against the Denver Broncos. And on the field that day was defensive back Ryan Clark. They lost to Denver with a last-minute field goal, actually. There it is. There's the hole. There's the kick. It's away. It's good. It's good. The game was at Empower Field in Denver. Which is, you know, high altitude.

And he got on the plane actually after the game. I was getting on the plane to come home and I told the trainer, I said, my spleen hurts. He had some really sharp stabbing pains under his ribs. And he knew it wasn't the normal bumps and bruises of playing a professional football game. I couldn't deal with the pain. I called, I was like, I'm going to die. If somebody doesn't get up here very soon,

I'm like, I'm not going to make it. So they stopped the plane on the tarmac, and he was rushed to the hospital. After a stint in the hospital, Ryan was sent home to Pittsburgh. For a month, he suffered fevers and excruciating pain. He couldn't eat, and he lost 40 pounds in the process. Eventually, after a battery of tests, doctors figured out what was wrong. Ryan had suffered a splenic infarction.

In other words, his spleen was dying. It was discovered that the root cause of this was sickle cell trait. It's not visible. I wasn't bleeding. My arms were still attached, you know, so it wasn't anything people could see to be like, yeah, dude, you're in pain. The high altitude combined with sickle cell trait had triggered this physical reaction. Robbing his blood's ability to transport oxygen to his organs, so necrosis set in or death of the tissue in the organs. Once they figured out what was wrong, Ryan was treated and began to recover.

He survived this horrible ordeal and he actually, you know, came back to play football and ended up winning the Super Bowl with the Steelers after this ordeal and he actually, you know, came back to play football and ended up winning the Super Bowl with the Steelers after this ordeal. So there is a bit of a happy ending to Ryan Clark's story. This thing, this sickle cell trait that nearly killed Ryan Clark in 2007, was passed down to him through hundreds of generations from his ancestors in West Central Africa, the Bantu, beginning nearly 8,000 years ago. The Bantu are a mix of different ethnic groups united by a common language family. They established some of the earliest human societies when they began cultivating agriculture.

Specifically, these Bantu farmers are clear-cutting for their yam and plantain crops. And essentially what that does is open up the canopy to allow sunlight in, which warms things up, and then you add water to irrigate your crops. And adding water to rivets in the ground, it's a cordial invitation to mosquito breeding. They unleash falciparum malaria. This is the most deadly one. This is the game changer. So very quickly, through natural selection, and this happens so quickly,

natural selection starts to promote sickle cell in the Bantu population to give them immunity to malaria. Sickle cell refers to the unusual shape of the blood cells that form as a result of this genetic adaptation. It's not completely understood how it works, but we do know that this unusual shape somehow protects humans from malaria. The mosquito actually literally changes our DNA. It attests to what must have been cataclysmic

and near-genocidal rates of malaria in Africa at this time. And it provided an incredible genetic advantage for the Bantu people. The Bantu are armed with essentially their sickle cell to rebuff malaria. Over the next several thousand years, they expanded into other parts of the continent. They swept through the south and east of Africa. Bantu culture spread far and wide. And so did sickle cell trait. But sickle cell trait wasn't just an advantage. It had some fatal downsides. If you were unlucky and both your parents passed down the sickle cell gene to you,

that's called sickle cell disease. and that's essentially a death sentence. Well, it was back then. Now, if only one sickle cell trait was passed down to you, you could fight off malaria and survive childhood, which was great. Except the only problem then was... The problem is it robs the ability of the body and the blood to transport oxygen. So you might, on average, before modern medicine, you'd live to the ripe old age of roughly 21 to 24 years old. This adaptation, which was passed down for a specific reason in a specific time and place,

stayed in the blood of the Bantu people for millennia. And when some of the Bantu were forcibly brought to the western hemisphere as enslaved people, the sickle cell trait came with them. This shows the legacy of the mosquito in our current populations with Ryan Clark and in this African-American population with sickle cell and these genetic shields. This mosquito, this tiny, tiny animal, changed the genetics of millions of people who traveled across a continent. And eventually, some of those people were captured and sent across an ocean, and their DNA would go with them. When we come back, how the mosquito might make you think differently about the American Revolution.

Hi, this is Agnish Dasgupta from St. Louis, Missouri, and you're listening to ThruLine from NPR. We all think we know the story of the American Revolution. People were mad about taxes, the Boston Tea Party broke out, George Washington and his crew took up arms and defeated the imperial British army with unconventional tactics. And while some of that is sort of true, there's a big, or should we say small, part of this story that is rarely mentioned. Mosquitoes.

It's 1778, three years into the American Revolutionary War. The first half of the war was fought almost entirely in the North. George Washington and the Continental Army were having mixed success and spent a lot of energy running from the British Army, trying to buy more time. The British are very upset that General Washington won't essentially commit to a decisive battle to end the war. And Washington knows he can't do this because he doesn't have anything. If he commits to a decisive battle and loses, the revolution's over. But as long as he can keep an army, however ill-supplied and under-equipped in the field,

the British have to defeat and chase this army. All the while, he's desperately waiting for help to come. He waits for his political lords, essentially, in the Continental Congress to get some supplies, get some allies, get some weapons, and hopefully get France on board. This is essentially playing cat and mouse, and it frustrates the British. So, they change their strategy. The British concentrated their forces in the southern colonies of Georgia,

South Carolina, North Carolina, and Virginia. Second in command of this campaign was General Charles Cornwallis, who landed in Charleston with 9,000 British soldiers. And these soldiers come primarily from northern England and Scotland, these British soldiers. So there was malaria in England, but these soldiers specifically are recruited from northern England and Scotland,

away from the malarial fenlands of England. So they're not what is called seasoned. What seasoning is essentially the more you suffer, the less you suffer. Now, I don't suggest this as an inoculation strategy, but generally speaking, the more you contract malaria, the less severe the symptoms are and the less likelihood of dying. So the American soldiers have been seasoned to their colonial malaria. They've had malaria. They've been seasoned to it. Where these British soldiers come over, they haven't been seasoned to their own English malaria, let alone colonial stew of malaria. And this new set of circumstances in the South forced Cornwallis to adopt some unusual tactics.

If you look at his campaign in the South in 1780, 1781, he is zigzagging all over the place. It is one of the strangest marches you've ever seen on a map. And so why is Cornwallis doing this? Is he running away from the Americans? Is he chasing the Americans? No, he's trying to find a healthy spot for his troops. With a third of my army sick and wounded, which I was obliged to carry in wagons or on horseback, the remainder without shoes and worn down with fatigue, I thought it was time to look for some place of rest and refitment. And he says this repeatedly in his correspondences. He says that malaria is ruining my army. And he's asking British loyalists in the southern colonies where there's a healthy spot. And because they're seasoned, they say, oh, just go that way. And then he gets there and his troops are cut to pieces by malaria again.

I am now employed in disposing of the sick and wounded and in procuring supplies of all kinds to put the troops into a proper state to take the field. I am, likewise, impatiently looking out for the expected reinforcement from Europe to enable me either to act offensively or even to maintain myself in the upper parts of the country, where alone I can hope to reserve the troops from the fatal sickness which so nearly ruined the army last autumn. April 10th, 1781.

As Cornwallis was running around looking for a safe, mosquito-free spot for his troops, he got an order from his superiors to retreat and fortify at the port of Yorktown in Virginia. Yorktown is a little hamlet situated in the tidewater estuaries between the James and York rivers. Essentially, it's rice paddies. It's marshland. So he holds up in Yorktown. French Navy comes. They're eventually joined by General Washington and the Americans, and they ensnare the British in Yorktown.

This is in August, which is prime mosquito time and prime mosquito country in these marshlands surrounding your town. His army was decimated, and in October, General Cornwallis surrendered. I have the mortification to inform your excellency that I have been forced to give up the post and to surrender the troops under my command. The troops being much weakened by sickness, as well as by the fire of the besiegers. In his correspondences, Cornwallis lays some of the blame for his surrender on malaria. Our numbers had been diminished by the enemy's fire, but particularly by sickness.

He's like, I don't have anybody who can even stand up to fight. He only has 35% of his troops, roughly, who are able to even stand up. Our force diminished daily by sickness to little more than 3,200 rank and file fit for duty. The rest are either sick, dead, or dying of malaria. The siege of Yorktown was the final battle in the war between the colonies and Great Britain, opening the path for the formation of the United States. So in a way, Deonofly's Mosquito is the founding mother of the United States,

and she deserves to have her nice proboscis face tucked in between Washington and Jefferson on Mount Rushmore. Our founding mother, the mosquito, looms large over the history of humanity. And as Tim told us, her reign is not limited to our past. She may completely transform our future. Human beings are crisscrossing the planet for trade, travel, business at record rates to record numbers of destinations in record numbers everywhere.

Disease is a constant baggage to human migration. Whether that be war, trade, travel, it doesn't matter. It's a universal creature and has been for forever, essentially. Her reach and her historical impact and influence kind of cross both time and space. Time is kind of irrelevant to her reach because at every stage, the mosquito and these pathogens have essentially been able to circumvent our frontline weapons to continue what they're pre-wired to do, and that's simply reproduce. So we are constantly trying new and innovative techniques to break this eternal stalemate that we've had with our deadliest enemy and deadliest predator. That's it for this week's show. I'm Ramtin Adablui. I'm Randabdeh Fattah. And you've been listening to ThruLine from NPR.

This episode was produced by me. And me. And. Jamie York. Lawrence Wu. Lane Kaplan-Levinson. Lou Olkowski. Nigery Eaton.

Fact-checking for this episode was done by Kevin Vocal. Special thanks to Radia Chowdhury and Steve Tyson for their voiceover work. Thanks also to Anya Grunman. Our music was composed by Ramtin and his band, Drop Electric, which includes... Anya Mizani. Sho Fujiwara. Naveed Marvi. And one last note. On April 16th, we're hosting a virtual trivia night.

We'd love to see all of you there. For information on how to sign up, go to our Twitter at ThruLineNPR. we're hosting a virtual trivia night. We'd love to see all of you there. For information on how to sign up, go to our Twitter at ThruLineNPR. If you have an idea or like something on the show, please write us at ThruLine at NPR.org or find us on Twitter at ThruLineNPR. Thanks for listening. you