Note: the following transcript is a radio script and contains audio cues and other quirks (including imperfect grammar) of the medium. It may contain typos.
Taylor Quimby: [On boat] When do they honk the horn?
Justine: [On boat]They didn’t do it! It’s the law. They are supposed to honk it three times when they leave the dock and they didn’t do it!
Last August I got on a ferry, and took off towards an island off the coast of Cape Cod, Massachusetts.
Taylor Quimby: [On boat] Nantuckeeeeet.
I was hoping for a horn, but apparently they only have to honk if it’s foggy. So I improvised.
Taylor Quimby: Try and sound like a horn. Nantuckeeeeeet.
Nantucket is a charming old whaling island, shaped like a flat boomerang, with a big tourist season but a permanent population of only about 11,000 people.
[clapping]
Band singer: Tick check. Tick check.
I was there to attend a meeting at the local library - a giant greek revival building called the Atheneum.
Band singer: Tick toxic, tick toxic…[music playing]
Someone walking in off the street might be under the impression they had stumbled into an evening of live music. But then, they might have second-guessed once they’d seen the free shortbread cookies shaped like mice, and listened to the lyrics.
Band singer [singing]: Giggling, wiggling rolling around. Can’t do that no more. Everything fun that we used to do, mom makes us do indoors. Tall grass, short grass, running around, just want to jump in the leaves. Small fry, bullseye red and inflamed, now I gotta brain disease. Why can’t someone help us?
Band: WHY?
Band singer [singing]: All this pain from a little tick? Why isn’t someone on this? It’s 2018, they’ve mapped the gene, please somebody science this shit.
This is local band Coq-Au-Vin. The organizers of this meeting were pulling out all of the stops… trying to fill seats for an important conversation about the future of the island.
Kevin Esvelt [at meeting] : Thank you so much for coming this evening on a beautiful summer’s day to discuss ticks.
This is one of the main speakers from the evening - Kevin Esvelt. I had already interviewed him in a studio before the event. He knows how to give a good soundbite.
Kevin Esvelt [in studio] : The West Coast has earthquakes. The heartland has tornadoes. The South has hurricanes. And in New England, our natural disaster is Lyme disease.
Kevin is a biochemist and so-called “evolutionary sculptor” working at MIT. And to understand what this meeting was about… you’ve got to know what a reservoir is… Not the kind that stores drinking water. The kind of reservoir that stores disease.
Kevin Esvelt : So a reservoir is what we what we think of when we say where is the source of this disease in the environment.
Blacklegged ticks are not typically born carrying Lyme disease. They have to get it from something - and typically they get it from feeding on a mouse, during their very first blood meal.
Kevin Esvelt: Now mice themselves, these white footed mice, they're not born infected either. They get infected when they're bitten by an infected tick.
Taylor Quimby: It’s almost like a chick...chicken or egg situation.
Kevin Esvelt : It is. So the more ticks you have, the higher the fraction of mice that are going to be infected.
Think of it this way: The mice are like mobile Lyme disease storage tanks, scattered all over the forest floor. And the ticks are delivery trucks - carting around the bacteria, dumping it into empty storage tanks, and filling up from other ones along the way.
Kevin Esvelt: [in Nantucket meeting] : There are nearly 300,000 cases… in fact there are more than 3000,000 cases of Lyme disease, every year, according to the CDC. Nantucket is among the worst affected areas in the country. And therefore the world. Why is there are a problem? Well it’s an ecological problem. So we at MIT came up with this idea that said, what would happen if we immunized the mice?
The plan that Kevin Estvelt was there to talk about is called Mice Against Ticks. Kevin is something of a pioneer in genetic research and his work has a lot to do with something you may have heard of called CRISPR. He’s not talking about manually giving mice a vaccine. He’s talking about altering their genes - and releasing thousands of modified mice onto the island.
He thinks he can use genetic engineering… to basically solve the lyme disease problem on Nantucket. And maybe... across the world.
Kevin Esvelt - Best-case scenario would be a 99% plus reduction in all diseases spread by the deer tick.
99% reduction. It almost seems… well you know the phrase. ?
Audience member: I’m curious what the panelists think could conceivably go wrong with this experiment, and what the worst-case scenario could be?
Sam Telford: The worst possible outcome is that it doesn’t work!
[mux]
Kevin [meeting] - We are biased. You should never trust an inventor to evaluate whether their technology is safe and effective. Because we’re still human, no matter how hard we might try, we will fail.
[Patient Zero theme]
I’m Taylor Quimby. So far, we've spent most of this series exploring Lyme inside the body. But lyme disease is part of a much larger ecosystem.... and now, we have the tools to alter that ecosystem - permanently.
But just how far are we willing to go to fight the spread of Lyme disease in the wild ?
Kevin Esvelt: There is no silver bullet. There is no such thing.
On this - the very last episode of our series - we’re zooming in on an experiment that might just hold the key to stopping tick-borne illness in it’s gross little tracks… and, we’re zooming out… to examine the ways in which our collective actions have been unintentionally accelerating us headlong towards this disaster.
This is not just a story about how an epidemic spreads throughout society.
This is a story about how the spread of society can create an epidemic.
This is Patient Zero.
[Theme plays then fades]
Jen Karberg: I'm not going to remember what the highest number is but you know someone pulled up something in the range of like 30 to 40 ticks at once just from one outing in the field.
This is Dr. Jen Karberg, research program supervisor for the Nantucket Conservation Foundation.
And yeah, she sees a lot of ticks.
Jen Karberg: Oh gosh oh it just makes it makes your skin crawl. Start to think about it.
Nantucket is covered in beaches and salt marshes scrub oak and pine barrens, and tall grasses. But despite the beauty, it’s not actually quite as biologically diverse as the mainland. There are fewer species of plants, fewer species of animals.
Jen Karberg: Your ecology your food web webs your net of the species that you have an island is almost always less than what you would see on the mainland.
And that makes it the natural world’s equivalent of a petri dish.
Jen Karberg: Islands are amazing places to do research.
Why? Because it’s contained. The ocean is a natural border, that limits the number of factors that can influence your experiment. So, if you want to see how change ripples through an environment, you’re more likely to see a direct cause and effect in an island ecosystem. You can introduce an element here, or take something away there… and see what happens.
But the experiment - if that’s what this place is - hasn’t always been conducted intentionally.
For probably 200 years or more, there were no deer on Nantucket. That’s according to the Nantucket Historical Society, or NHA.
But then...
Jen Karberg : So back in the 1920s there was a buck that was found swimming and the NHA reports that they were swimming out in the fishing grounds….
According to local legends, fishermen pulled the lone buck aboard and set him free on the island.
Kevin Esvelt: And the people there felt sorry for this lone deer, which became sort of a fixture when people saw him around.
Kevin has heard this story too.
[buck grunting]
Uh by the way, bucks deer sound kind of like mutant zombie cows.
Jen Karberg: So then a couple of years later someone actually went and got some does from Michigan as what I've heard… They were brought from Michigan.
Kevin Esvelt : And fast forward and you have a lot of deer on Nantucket
Like, a lot of deer.
Jen Karberg : Yeah I think it was 2013 was the last time they did like an overall survey of the island and the estimate and estimated numbers are between 45 and 55 deer per square mile.
Now… There are, roughly speaking, three main ingredients in the lyme ecosystem. Ticks, mice… and deer. The thing is, deer don’t do the same job as mice - They’re what scientists call incompentent reservoirs... It doesn’t mean they’re stupid… it means they don’t actually get infected with the bacteria that causes Lyme disease… and they don’t give the ticks lyme disease.
mice are storage tanks, ticks are delivery trucks, deer are neither… They’re delivery truck factories - Their presence helps to multiply the number of ticks… because infected adult ticks literally reproduce on top of them, before dropping off to lay their eggs.
Kevin Esvelt : So every female tick on a deer will lay something like two thousand eggs. There is typically a thousand ticks on a deer, meaning every deer you see is a walking million ticks in the next generation.
Taylor Quimby : Uh, man, that is a ton. That is gross.
Kevin Esvelt : Yeah. You can't really watch Bambi the same way again.
[mux]
Gross as all these details may be, they present an opportunity… if all three of these really are required to spread Lyme, well that gives you three potential avenues to interrupt the cycle.
And since an island is a petri dish, as we’ve discussed - well then, why not just remove one of the ingredients and see what happens?
It turns out, that experiment has been done before - on another island not too far away.
Seth Bogdanove: Hi my name is Seth Bogdanove, my family has been summering on Monhegan since about 1918.
About 175 miles North of Nantucket, is a way smaller chunk of rock off the coast of Maine - Monhegan
Seth Bogdanove: It’s about the size of central park, it’s about a mile and a half by three quarters of a mile.
And on this rock, there was an over-abundance of deer.
Seth Bogdanove: There might have been 20 to 30, possibly as many as 50 at one time.
According to one account I’ve found, there may have been as many as 100.
Seth Bogdanove: And they were kind of scraggly at that. They were, I have a picture somewhere I took of one of them, it didn’t look healthy.
When he was younger, Seth remembers pulling ticks off his ankles left and right - a few locals had even gotten Lyme disease. So, in the 1990s, a proposal was made - to change the makeup of the petri dish, permanently.
Seth Bogdanove : It was about 50/50, I mean people loved them, because they were nice to look at. On the other hand there was the problem. And in the end, the health of the people on the island was more important than how pretty the deer were.
Taylor Quimby: So what was the solution? I mean.
Seth Bogdanove: They killed them. No, they killed them.
It took three years. The villagers hired a sharpshooter to do the job. They killed 72 that first winter. 35 the next year. For some reason, the number of ticks actually went up. And then, a final vote: 31-23 in favor of complete eradication.
Seth Bogdanove: THe worst I ever saw was half a carcass that was left out.
The last 6 deer were killed in 1999. And a few years later… no infected ticks. It worked.
Kevin Esvelt : On islands that have removed all of the deer there has been an utter collapse of the tick population. And thus the number of infected ticks in the disease almost goes away.
Is this a solution? It certainly worked on Monhegan, which to this day is deer-free. . So... Why not Nantucket? Well… the bigger the deer population, the tougher the problem.
Kevin: So yes, if you get rid of EVERY last deer, but it has to be every last deer. Because islands that have done very extensive culling have seen a reduction, but not the total collapse of disease transmission that islands that have removed all of them have seen.
Kevin: So you could… if you could.
Even though Nantucket is small, it’s many times the size of Monhegan - instead of a one hundred deer , there are thousands. Efforts to even cull the herd have been controversial - so not only would it be logistically more difficult to eradicate them all, it’s politically unfeasible.
But hey - there are two other organisms in the trifecta, right? Two more opportunities to stop the cycle...You can’t kill all the ticks, again, for logistical reasons… .
And you wouldn’t want to kill all the mice, in part because they play an important role in the ecosystem… But what if you don’t have to? ? What if you just make them immune to Lyme disease?
That’s what was being discussed at the Library on Nantucket last August.
Kevin Esvelt [at meeting] : How are you going to introduce immunity among mice? And the answer is you have to introduce engineered immune mice. How many mice? Lots of them.
So the number one question is is this going to cause unexpected ecological effects? And the answer is we don’t know for sure! Ecosystems are complicated. We can’t tell you for sure if there are going to be ecological effects. That’s why you have to start small somewhere else, a small mostly uninhabited island.
Kevin’s plan is pretty modest, as far as gene-editing goes. Engineer mice that are immune to lyme disease… breed those altered mice in the thousands… release them on small mostly uninhabited islands, near Nantucket… just to see if it works, and make sure nothing goes terribly wrong… and if nothing goes wrong,, release them en masse on Nantucket - two to three hundred modified mice for every 100 wild mice on the island.
[mux]
If that sounds a little crazy, you should know that is only the tip of the iceberg.
As Michael Spector, a writer for the New Yorker and the evening’s moderator said..
Michael Spector: It’s silly to pretend that people like me are spending years here, focusing on this issue JUST because it’s about mice and ticks on Nantucket. It’s about a fundamental way to change living beings permanently.
[mux]
Here’s the thing you should know about Kevin Estvelt. He basically invented the ecological equivalent of the atomic bomb.
I don’t mean that his invention will destroy everything in a four mile radius or result in a radioactive cloud. What I mean, is that this is an idea that could change the world as we know it… an idea that cannot be put back in the box.
When scientists began to understand the power of CRISPR, the gene-editing tool, they thought, wow, we can use this to alter living individuals.
But Kevin took it a step further - he thought, what if we can take this gene-editing tool… and build it, encode it, into an organism’s DNA.
Any particular gene has a fifty percent chance of being passed onto the next generation, right?
But with Kevin’s new idea - what he calls, the “gene drive”... you could use CRISPR to guarantee that some genes are ALWAYS passed down.
And if an animal was edited in this way, and then introduced into the wild… before long, the change could spread through the entire population. It could be irreversible… permanent.
Think about it… what’s to stop some scientist, or company, or government, from going rogue: permanently modifying mosquitoes to stop one disease, only to introduce another… or trying to make the perfect potato, only to wipe out every other breed… or even worse, to use a gene drive on humans! designer babies, eugenics, the zombie apocalypse for god’s sake… This is a pandora’s box, for better or worse.
These frightening concerns are more or less summed up by Jeff Goldblum’s character in the film Jurassic Park.
Hammond: [cackles]
Jeff Goldblum: The lack of humility about nature being displayed here staggers me.
Hammond: I don’t think you’re giving us enough credit. Our scientists have done things which nobody ever has ever done before.
Jeff Goldblum: Your scientists were so preoccupied with whether they could, they never stopped to think whether they should.
This idea has made Kevin Estvelt think very hard about his responsibility as a scientist.
Kevin Esvelt [in studio] : So I am personally responsible for introducing the world to a technology that could allow us to edit wild populations, and thus their associated ecosystems. So that means I have a personal responsibility to ensure that we... Either don't use this at all or much more likely, only use it thoughtfully. And humbly. And I’m a little bit disturbed because we really don’t really have good mechanisms for developing technologies intended to alter the shared environment.
So here’s Kevin’s secret. He’s not just on Nantucket to combat Lyme disease. He’s here to try and change the way we do science - and if there were a different disease that presented the same opportunity, I think he would just as happily have tackled that problem instead.
So his plan is to bring the debate into the open, and to have a conversation with the public BEFORE going to the lab and creating an irreversible frankenmouse. He knows that he could do it - he’s giving the public the chance to decide whether he should.
Kevin Esvelt [in studio] : If Nantucket and the Vineyard and the islands decide they'd rather not move forwards if they all vote against it, then that's probably it. We will walk away. And that's the way it has to be, because the world could use a salutary example of a community saying no. And scientists walking away.
In order to do this, Kevin Estvelt has gone and done what very few people in his position would, and what is kind of uncommon in Lyme disease. He’s assembled a steering committee, and deliberately included at least one very vocal critic of the project.
Danica Connors: God it was last year and I just saw in the newspaper and because of my background of what I'd like to see what this is about.
This is Danica Connors. I met her at a coffee shop on Nantucket. She’s a big gesticulator - I was worried she was going to accidentally smack the microphone out of my hands. She’s a self-described lyme literate herbalist, who offers alternative therapies and shamanic practices for people living with Lyme or Chronic Lyme on the island.
Danica Connors : To this day I’m like how do you put shamanism into a soundbite. The spiritual way of connecting to the environment and your relationship to it. That was that was pretty good.
Danica says she has Lyme disease… but after a year reporting on Lyme, I’m confident that her story would lead infectious disease doctors to raise an eyebrow.
Danica Connors: I don’t even know the beginning… I’ve been bit anywhere ten times and up. All of the tests negative straight across the board, negative negative negative negative except for the fact that every full moon right around it I would come down with a raging fever that would knock me on my behind.
And not just her personal story - Danica is putting some pretty hardline rhetoric out there that isn’t settled science. She makes the spirochetes that cause Lyme sound like tactical smart-missiles.
Danica Connors: There's no antibiotic there's, no herb there's no nothing that is going to be able to remove them and kill them completely from the body...They’re too smart, they adapt too much. However, what we can really do… which is astounding, is we can live harmoniously with them.
Again, this isn’t the view of most scientists and doctors. And yet, at the meeting in the library, Kevin Estvelt almost gleefully pointed out Danica’s involvement… because he knows that the only way to responsibly pursue action on this scale - is to include your skeptics.
Kevin Esvelt [in meeting]: Danica has talked a lot about the project. If you have any concern or criticism that you feel uncomfortable raising with us, she is a local resident, she is on record of being skeptical of the project, if you feel uncomfortable telling us directly or bringing it up here, please raise it with Danica and she will make sure that your concern is heard and it is responded to.
And so far, that inclusion seems to be working, in a way - Danica doesn’t endorse the project… but she’s not outright trying to scuttle it either.
Danica Connors : I've never seen anything like this that they're being very honest very open and putting the choice into the community's hands. It is community driven science which is the only reason why I'm on this panel. Otherwise I would’ve said no. Because I don’t approve of the program.
Community-driven science… Given everything we’ve learned - about how controversial Lyme disease is - it’s pretty incredible to see this kind of cooperation. In fact, in the meeting I went to - I noticed not one person brought up issues related to testing, or chronic lyme. For once, it actually seems like everybody is on the same team.
Is this a lesson for Lyme-world writ large? Or a sign that things are changing for the better? Disease leaves people feeling powerless, held hostage by things they cannot see.
And given the history of Lyme disease, you have to wonder if the only way scientific and medical authorities can gain trust is through patient, inclusive discussion: by empowering people that aren’t typically given a voice.
Of course, there are trade-offs to that approach.
Ruth Faden: Kevin said something very interesting when he was speaking, he said, he wanted to make sure everyone to have a voice. Everyone having a voice is not the same as everyone having a veto.
At the library, bio-ethicist Ruth Faden, raised an important point about the project… and what it means to involve the community.
Ruth Faden: This isn’t going to work if one person holds it up.
Including Danica, Kevin Esvelt may have anticipated, and circumvented some pushback to the project. But by giving the community a choice, he allows a potential solution to be watered down in ways that might not have as much impact. And already, the community has decided it’s not comfortable with some of Kevin’s ideas.
Danica Connors: You’ve got about 40% of people saying, no, absolutely not, this is GMO I’m not touching this.
Kevin Esvelt [in meeting] : As someone who does gene editing, if you say you can only use DNA from this one species, that’s like working with our hands tied behind our back. But this is your environment, it’s your call. And the clear majority said, only use white-footed DNA, don’t do anything else.
Kevin’s grandest invention— the gene drive — isn’t being utilized here… He’s breeding immune mice… but that immunity won’t always be passed down to the next generation… And eventually, in 20, or 30, or maybe 100 years… the number of infected ticks will start climbing back up. And Lyme disease will return. And this plan, which isn’t at all the atomic bomb I warned about, will only work on an island... in a petri dish, where natural borders keep the experiment in-bounds.
In the real world - for the rest of us - it’s gene-drive or go home. Jurassic Park or bust.
Kevin Esvelt : So this won’t really work on the mainland. You’re going to need the somewhat, at least slightly more powerful version.
Islands make for wonderful petri dishes, because there are fewer complications… fewer variables to consider. But like all scientific experiments, that’s also their drawback. Because the real world - the vast, complicated space outside the walls of the petri dish, is less predictable… and harder to understand.
Rick Ostfeld: If the Lyme gods wanted to create the maximum illness they would have plenty of deer plenty of mice that would produce plenty of infected ticks.
Disease ecologist Rick Ostfeld Senior Scientist at the Cary Institute of Ecoystem studies, in New York State.
Rick Ostfeld: So yeah I think there is some truth to this trifecta. It can get a little distorted when there's too singular a focus on those particular species.
Why? Unlike Nantucket, where there are no foxes, coyotes, racoons, no eastern chipmunks, no opossums, or skunks, mainland forest ecosystems have a dizzying number of variables.
Like deer, many of these animals are either don’t get lyme disease, or don’t exchange it with ticks as well as mice do. . And so every time a tick bites one of these other animals, it changes the equation a little Diluting the cycle of Lyme in the environment.
With this many factors, the math starts to get out of hand.
Research shows that if you increase the number of foxes… they eat more mice…. And tick infection rates go down.
If you increase the number of opossums and raccoons - animals that aren’t as good a reservoir for Lyme as mice - more ticks feed on them, instead of the mice…. And tick infection rates go down.
But if you increase the number of coyotes… they scare off the foxes... eat the opossums… and tick infection rates go up.
And that’s just the first layer of complexity. Ready for the next?
In an area with high biodiversity… lots of different types of animals… where tick infection rates are already low… if you remove shrews…. The infection rates go down even more.
But In an area with low biodiversity, not that many animals… where tick infection rates are high already… if you remove shrews… same thing we just did in the last scenario… the tick infection rates do the exact opposite. They go up.
Biodiversity is a huge part of whether and how lyme rates increase and decrease in a given area, and it is just hard to measure.
Taylor Quimby : Have you been following the Mice Against Ticks Project? Some of the stuff in Nantucket, Martha’s Vineyard?
Rick Ostefeld: I have yes. There’s some things they’re doing very much right...
I asked Rick Ostfeld what he thought about the Mice Against Ticks project. He said, the community-driven aspect is really admirable. But he also said, we’ve got to proceed carefully.
Rick Ostefeld: Quite frankly we we humans have a terrible track record in anticipating the consequences of having new species exotic species, or exotic genotypes, in a natural ecosystem. We think we can guess or hypothesize what the impacts are going to be but we're often really wrong.
In other words, we can do all the careful science in the world and still not know for sure what would happen if we immunized the world’s mice to Lyme disease…
And given that, you can’t help but worry that people who have this perspective...
Sam Telford: The worst possible outcome is that it doesn’t work!
...are not using their imaginations.
Jeff Goldblum [clip from Jurassic Park] John the kind of control your attempting is not possible, listen if there’s one thing the history of evolution has taught us it’s that life will be contained, life breaks free, it expands to new territories, it crashes through barriers painfully, maybe even dangerously, but I’m simply saying that life… uh… finds a way.
Coming up… we wrap up the series, by trying to answer two big questions: how did we get here, and where are we going?
That’s when Patient Zero continues.
[break]
I want to tell you a story. It’s the story of North America… Particularly, the area we now call New England… which a few hundred years ago, would have looked a lot different.
Well, kind of. I mean, basically, there were a lot of trees.
Carly Sponarski : Pre-colonial New England had a lot of forests, old growth forests.
This is Carly Sponarski, a biologist at the University of Maine. These were the days of wolves, of deer and moose and cougar, the era when billions of passenger pigeons would darken the skies of the continent... the time of the Algonqian peoples,
Rick Ostfeld: We presume that the Native Americans in the precolonial times probably got bitten by infected ticks and got Lyme disease
This again, is ecologist Rick Ostfeld. Lyme disease has been around a looong time. At least 60,000 years, according to research on bacterial genomes done by the Yale School of Public Health. So how come it took so long for us to notice it?
Carly Sponarski : As European settlement came, a lot of resource extraction occurred… resources including animals and timber.
Resource extraction: The multi-purpose euphemism that in plain language means cutting trees, and killing animals.
In the first couple hundred years of settlement, Europeans introduced new diseases and transformed the landscape… they drove out or killed indiginous peoples… forests were razed, and turned into farmland.
While their habitat shrank, deer were hunted to a fraction of their former population - half a million pelts were being traded and sold ever. Their natural predators, the grey wolves, turned to livestock for prey - and were also subsequently hunted to near extinction.
In a few communities in Southern New England, these changes were really dramatic.
Rick Ostfeld: So where the landscape was once about 90 percent forest cover, it went down to about 10 percent forest cover at the height of subsistence farming.
And ticks… well, they would have had a hard time too.
Rick Ostfeld : Then for a while the risk of Lyme disease went down to zero or near-zero in much of the northeast.
But then… Another shift.. Industrialization.. A new economic paradigm.
Carly Sponarski: And now we have reforestation…
Farmland was abandoned.The trees start coming back.
Carly Sponarski: In these areas, agriculture is being transitioned back into forests.
But this isn’t the same world as it was before…
The deer population is swelling, but wolves continue to be slaughtered.
And then, in the 20thcentury, there’s another thing that’s changing the landscape - the automobile.
We’re building homes and roads - cutting back into the forests…
And the neighborhoods cropping up… are different
Taylor Quimby: Do you kind of um… hate the cul-de-sac?
Shima Hamidi: Well, I...I… uh...
This is Shima Hamidi.
Shima Hamidi: I would say, personally I am a person who um… I’m not a fan of driving.
A professor of planning at the University of Texas at Arlington - she has been studying the shape of American housing.
Shima Hamidi: Scattered, single use, extremely low-density, and with the street networks that are more cul-de-sac, versus grid street patterns.
In the mid-20th century, Americans - and american developers started to transform the way our communities branch out… leapfrogging across natural areas, and then slicing odd shapes into the landscape.
Shima Hamidi:The land is inexpensive, and it’s cheaper, and you can buy houses that are larger… And so that really leads to what we see now in urban sprawl. I would say after second world war.
And while that may have seemed convenient at the time, there are secret costs to this new lifestyle… it’s more sedentary, people have to rely increasingly on cars… there is an increase in the risk of getting Lyme disease. Because now, the forests have returned. Wolves are all but extinct in the northeast, and the deer population has exploded. And all those little cul-de-sacs and leapfrog developments have cut up the forest into little parcels, and increased the amount of forest edge next to homes.
Here’s Kevin Esvelt.
Kevin Esvelt:The mice do best, not in the deep woods, not in the undisturbed woods, but on the edges of forests. So when we encourage forests everywhere, but then we carve it up with roads and houses where maximizing the forest perimeter. And that means we're maximizing the amount of mouse habitat. That's why in many ways your risk of getting Lyme disease is higher near your house than it is in the remote parts of the Appalachian Trail.
Remember way back to episode 1? When I talked about the third point of the Epidemiological triangle? It was the environment. And in the case of the lyme epidemic, it’s the point that we have been unintentionally sharpening for hundreds of years.
From housing and transportation, to white flight and agriculture, a dizzying number of cultural factors have led us to maximize the number of deer - more than 30 million in America today. To maximize the number of mice - by fragmenting forests in ways that push away predators. To minimize the other animals that would help dilute Lyme disease in the environment. And for all those reasons, to maximize the number of infected black-legged ticks…
This is the stage that was set for Lyme disease in 1975, when Polly Murray’s kids were out playing in the woods of Lyme, Connecticut. .
Mary Beth Pfeiffer : The factors, the conditions all sort of came together in the 20th century to make it a perfect time to be a tick on Earth.
This is Mary Beth Pfeiffer. She will tell that there is one more powerful way that humans have given tick-borne disease a global leg-up. A topic that just seems unavoidable these days.
Mary Beth Pfeiffer : Ticks are moving to new places where they didn’t live before. Now is this a slam dunk? No. But there is a wide consensus in the scientific community that one of the prime movers and drivers of ticks in the environment is climate change.
This is the central argument in Mary Beth’s book: Lyme: The First Epidemic of Climate Change.
It’s a big assertion - and so not surprisingly, it takes a few steps to arrive at this conclusion. Let’s start with movement.
Daniel Sonenshine : So a tick attaching to a wide ranging deer can be picked up in one county and migrate over the course of a week during its feeding cycle to maybe two or three counties.
Ticks don’t travel far by foot - but they are nevertheless, incredibly mobile.
This is Daniel Sonenshine - professor emeritus at Old Dominion University, and author of Biology of Ticks. He told me that some ticks have also known to be spread via on the backs of livestock, shipped around the country on trains
But what really gets them around… birds. Did you know ticks can fly?
Daniel Sonenshine: Canadian authorities that I've read some articles about it suggests that somewhere between 50 and 100 million or a hundred and fifty million larval animal study scapula is dropped off into southern Canada every year.
Wherever the hosts go, the ticks go… Dropping like bombs off the backs of birds into new territory by the millions. But historically, that hasn’t meant they’d always survive. Previously, if a bird deposited a tick too far north, or it fell off on a beach or in a bog, it’s journey would come to an untimely end.
Different ticks prefer different environments - but generally, they don’t like it too cold… and they don’t like it too dry.
So this is where climate comes in. Because now, with global temperatures are going up, and many areas are experiencing wetter weather, the ticks have more places to gain a foothold… and survive the journey.
Dan Sonenshine says that black-legged ticks are spreading into Canada, increasing their range at a rate of 28 miles per year…
Which means Lymeworld is spreading to the north. All of the confusion and concern - now you can read about in the Calgary times, the Winnipeg Sun, the Montreal Gazette.
News clip 1: Lyme disease is an equal opportunity condition affecting Canadians of all ages.
News clip 2: In the last decade, case of Lyme disease have risen dramatically in Canada.
News clip 3: I was first told that there is no Lyme disease, north of Barre….
News clip 4: I got so bad two years ago, my wife had to come off of work and uh…
News clip 5: ...says blood tests used to detect Lyme disease in Canda are inadequate…
News clip 6: We’re seeing diseases that we never used to see, that we never were trained for and I believe part of that is climate change.
And perhaps most importantly, the climate and other factors I’ve mentioned in this episode, that are helping to spread Lyme disease... are helping to spread all sorts of tick-borne pathogens.
Daniel Sonenshine: The Gulf coast tick… Amblyomma maculatum.
The gulf coast tick has been marching away from the gulf coast - that can carry something similar to Rocky Mountain Spotted Fever.
Daniel Sonenshine :Then there is the lone star tick…
That spreads something called ehrlichiosis… And it’s been creeping north for decades.
Daniel Sonenshine : ...All the way into New England now, and along the coast.
There’s babesia, anaplasmosis, the Powassan virus… And there are ticks and tick borne diseases that may never make you sick, but could disrupt our lives in other ways.
Sonenshine: Amblyomma variegatum. The so-called tropical bont tick, b-o-n-t.
The tropical bont tick hails from africa, but travels by feeding on migrating egrets, and has made its way all the way to the island of Guadalupe, not far from Puerto Rico.
Daniel Sonenshine: It attacks cattle. It's the vector of a deadly disease called heart water. It’s extremely lethal. The lethality for cattle is is way up in the 80 to 90 percent range. And we're talking about islands very close to the Florida coast.
All across the country, and the world, ticks are ambling into new territory… And as they do, we’re discovering new pathogens - some, that are very much like Lyme disease, but not quite the same - others that are more rare, but more deadly.
What other tick-borne pathogens are still undiscovered?
We don’t know. But I can tell you - this problem is going to get worse, before it gets better.
At the meeting on Nantucket, experts were debating the ethics of how and whether to engineer mice to help fight Lyme disease. It was fascinating and important stuff. But one of the most memorable moments from the meeting on Nantucket… was when an audience member asked a very practical question.
Audience member: What I’d like to know are what are the sequence of events between now and when mice are in the field? Your modified mice?
Kevin Esvelt: I can tell you that the earliest possible date that you would be able to vote on whether to release these mice is probably 7 years from now.
[moans and gasps from crowd]
Kevin Esvelt: You’ve got to keep in mind, we've got to get FDA approval, we’ve got to make the mouse, we have to breed up 1000 of them for a small island field trial, we have to wait two years for the results of that field trial, the independent study of ecologists, we need FDA approval, probably or possibly EPA approval we need state fish and wildlife approval, we need YOUR approval, and at any point the steering committee can say nope that’s it, nantucket’s out, and we walk away.
As we wait for solutions, even the most basic prevention measures - the sorts of things people are already doing - aren’t guaranteed to help. Rick Ostfeld at the Cary Institute of Ecosystem studies has been doing a five year study of two types of household tick killers that could be used in backyards across the world. You would think we would know by now whether this is a good strategy. But not yet.
Rick Ostfeld: Well no one has yet been able to reduce ticks sufficiently in the right places to the right degree to demonstrate a reduced incidence of tick borne disease. If it's successful then we have a recipe. If these two methods, done so thoroughly and aggressively for a long period of time at the scale of entire neighborhoods, if they don’t work… then maybe we don’t give up completely on environmental control of ticks but it would sure suggest it’s too tough a nut to crack and we’re just not going to get there.
Carly Sponarski is looking at development, specifically logging and forestry practice… how can we manage forests differently to reduce Lyme disease?
Carly Sponarski: We’re looking at ground cover, like leaf litter, we’re looking at tree composition, the age of trees…
...but even with some data collected, she says it’s too soon to make any predictions about what exactly would help.
Taylor Quimby: What if we just cut all the trees?
[Carly laughs]
Taylor Quimby: You’re laughing, I’m not!
Carly: Okay, well cutting all the trees… It’s an interesting suggestion. I think there’s more research to be done before we go to that extreme management option.
In fact, one of the only things that will actually reduce your risk… is a fashion faux pas.
Carly Sponarski: You know putting your socks over your pants, wearing long pants to begin with and putting your socks over your pant leg, wearing high boots, wearing long sleeves.
Taylor Quimby: You just don’t see that many people who actually do the socks over the pants thing.
Carly Sponarski: Not you don’t. But it has been shown to minimize… when it comes to human behavior, it’s all about your sense of personal risk. So if you’re not that worried about ticks or tick-borne disease, than it might be something you’re not interested in doing…
In the forty plus years since Lyme disease was first recognized and named, we have come so far. We have learned so much - about spirochetes, and inflammation, and symptoms, and society.
But the best technology currently available for stopping ticks, are socks and pants.
As I’ve said before, the pace of science is slow. You may have heard about a new vaccine that’s being developed by a European company. It’s even been fast-tracked by the FDA. Frankly, this is the real fix - the one that doesn’t require genetically altering the world’s population of white-footed mice.
But don’t get too excited - the earliest that drug may hit the market is 2025.
If things keep going the way they are now… that means somewhere between one and half to two million Americans will get Lyme disease before a vaccine becomes available. And ten to twenty percent - hundreds of thousands - could wind up with Post-treatment-Lyme-disease syndrome. Will they get a voice? Will they be in on the conversation? Or, like Polly Murray, will they have to fight to be heard?
Polly Murray: I felt that there was some, something there but the medical profession said that there is no such disease that has the number of symptoms that you are exhibiting.
Allen Steere : I said many times that the study of medicine is humbling.
No matter how incredible modern medicine may be - it’s worth stopping to remember - we are a long, long way from having it all figured out.
Lawrence Altman : Scientists have to be humble.
Disease preys upon every aspect of human society - no matter how well we adapt to life on this planet, it adapts with us.
Yvette Cozier: Keep in mind and keep the humility that we don’t know everything.
Charles Raison: We don’t know how it works.
Monica Embers: I don’t think we have enough data to determine that.
John Aucott: It’s okay to tell patients you don’t know.
And no matter what epidemics we solve, what health crises we put behind us… The work is never done. There will always be another patient zero.
[montage of news clips, Patient Zero theme]
Patient Zero is produced, and reported by me, Taylor Quimby.
Throughout this series, I’ve gotten invaluable editing help from a number of amazing colleagues, including Justine Paradis, Jimmy Gutierrez, Hannah McCarthy, Nick “Clark Stanley” Capodice, Annie Ropeik, Jason Moon, Todd Bookman, Jacqui Helbert, and Cori Princell. All of them helped to shape this series in ways big and small, and I can’t thank you enough.
Sam Evans-Brown is Patient Zero’s senior Producer - who aside from having critical reporting chops, is a genuine delight to work with, and routinely knows how to keep the anxiety from getting too high.
Erika Janik is Executive Producer, who besides keeping me on track, shielded me from the work that I couldn’t handle, and gave me permission to focus on the work that I could.
Fact-checking for this episode by Amy Tardiff - without her, I would have told a fair share of lies.
Special thanks to Sara Plourde for the amazing graphics - she has forever ruined the color of lime koolaid, so kudos for that. If you haven’t checked out our website, patientzeropodcast.com, do it - you can see all of her work there.
Maureen McMurray is Director of Content - this series would not have grown so large if it weren’t for her trust and faith that we had a story worth telling.
Patient Zero’s Theme was composed and performed by Ty Gibbons, and it is a rare earworm that I don’t mind humming all hours of the day.
Additional music in this episode by Blue Dot Sessions, Zach Nugent, Jason Moon, Podington Bear, and Disasterpiece.
Credit music by Deerhoof.
Thanks to all of the listeners who contributed their voices via memos and emails.
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