JAD ABUMRAD: Hello, I'm Jad Abumrad.

ROBERT KRULWICH: And I'm Robert Krulwich.

JAD: This is Radiolab. Our topic today?

ROBERT: Parasites.

JAD: Parasites!

ROBERT: Now, we've met them. They're nice. And we've met them when they're not so nice.

JAD: [laughs] I don't know that we've met any nice ones, really.

ROBERT: Oh, we haven't? I thought that ...

JAD: Oh, the blood flukes! They were pretty nice. Yeah, they were nice.

ROBERT: So now the question is, let's just talk about scale. I mean, for the most part, they're irritating and little, and they seem kind of ...

JAD: Invisible.

ROBERT: ... invisible and sort of offstage.

JAD: Yeah.

ROBERT: But when you back off a little bit and consider them, you know, in the effects that they have on the world?

JAD: They're actually these powerful sculptors of monumental narrative.

ROBERT: In other words, these are little guys telling very big stories.

JAD: In fact, here's an example. Recently I went to visit a guy named Dickson Despommier up at Columbia University. He's a parasitologist and—well, he does a bunch of different things. And we ended up talking about—well, he told me this crazy story.

DICKSON DESPOMMIER: The story I love telling the most.

JAD: Oh, and before we start, I just want to say one thing? The following two stories contain moments that are a little bit gross. Just want to make sure you've been warned.

DICKSON DESPOMMIER: The story I love telling the most is how we eradicated hookworm.

JAD: The story begins in 1908.

DICKSON DESPOMMIER: John D. Rockefeller Sr.

JAD: Really rich guy is sitting in his New York office and he's thinking ...

DICKSON DESPOMMIER: How can I make more money selling something to the South?

JAD: Yeah, "I've got all this money, got all these resources. I just need a new market." And in terms of new markets, the South was pretty much untapped. If only those damn Southerners ...

DICKSON DESPOMMIER: Would just get off their butts and get going.

JAD: Problem was, they weren't. They weren't getting off their butts.

DICKSON DESPOMMIER: The farms were not operational. The economic engine was turned off.

JAD: The economy was in the toilet. And so John D. Rockefeller wanted to know why.

JAD: Why aren't they producing more?

DICKSON DESPOMMIER: Yep. What's happened to their economic engine?

JAD: So he thought ...

DICKSON DESPOMMIER: "I know. I'll form a commission."

JAD: Yeah!

DICKSON DESPOMMIER: So he sent out a bunch of economists and sociologists and people like that on the original Rockefeller Commission. They did everything a commission could possibly do to try to find out why these Southern gentlemen were not rising to the occasion. And they came back with the following conclusion: well, we don't exactly know what's wrong, but we think that these people are sick from something because they don't behave like we do.

JAD: What does that mean?

DICKSON DESPOMMIER: They are slow. [laughs] Not mentally. They're slow physically. They're pale. I'll give you an example. Remember the movie Deliverance?

JAD: Sure.

DICKSON DESPOMMIER: Okay. Remember that little guy that played the banjo?

JAD: I remember the other scene that we all remember. We're not gonna talk about that.

DICKSON DESPOMMIER: No, we're not. No, we're not. But if you can recall what that little banjo player looked like. Little wiry looking guy. But he looked old.

JAD: Sickly pale.

DICKSON DESPOMMIER: Yeah, sickly pale, and yet an adult.

ROBERT: Well, wait a second. Wait a second. That is not a description of all Southerners.

JAD: No.

ROBERT: That's a description of one teeny corner in a ...

JAD: No. But what the commission did say about a lot of these Southern people that they encountered is that a lot of them, they just don't look right. They looked weak. They looked wan. They looked kind of—wan? Wan.

ROBERT: Wan.

JAD: Wan.

ROBERT: They were wan.

JAD: Pale, lethargic.

ROBERT: It's interesting. Wan or wan.

JAD: Wan.

ROBERT: You choose.

JAD: [laughs] So the thought was that maybe these Southerners had some kind of laziness disease. This is really what a lot of folks thought. But one member on the committee suggested to Rockefeller, "You know what? Perhaps these people are anemic."

DICKSON DESPOMMIER: Anemic. They're anemic, do you say? Yeah, they're anemic. It sounds like a medical problem, then. Maybe they're not lazy after all. Maybe they're anemic, and maybe they're just weak.

JAD: Next thing you know, Rockefeller puts together another commission, this one with doctors, and he sends them ...

DICKSON DESPOMMIER: Back down to the South to find out what the basis for the anemia was. And not only did they find anemia, but they found a correlation of the anemia with soil types. That's bizarre. Sandy, loamy soils? Anemia. Hard-packed clay soils. No anemia. Sandy, loamy soils? Good farmland. Hard-packed clay soils. Not such good farmland. So all the rich farmers were anemic, and all the poor farmers were doing okay.

JAD: And this seemed to be a clue. The incidents of anemia was linked somehow to the soil—maybe! Bum, bum, bum!

ROBERT: Yes?

JAD: Something was in the soil.

DICKSON DESPOMMIER: That's correct. So somehow they hit upon this idea of looking for hookworm.

JAD: The hookworm.

DICKSON DESPOMMIER: The hookworm!

JAD: So they thought, "All right, let's run some tests."

DICKSON DESPOMMIER: And when they did, big time. They discovered hookworm big time. So the anemia is due to hookworm.

JAD: Now the question became: how are these Southerners getting the hookworm and giving it to one another? And a pretty good place to start to look for an answer was their feces, because if these hookworms are in you, they're gonna come out of you when you go to the bathroom. So they asked these Southerners, when you guys defecate, where do you do it? And most of them said something like this ...

DICKSON DESPOMMIER: "I defecate over there. You see that tree over there? That's where I defecate. So I defecate over there. But I live over here."

JAD: Okay. So then the investigators asked the next question: When you go to that tree and do it, do you—do you wear any shoes? Most of them said no.

DICKSON DESPOMMIER: Barefoot, just like everybody else. Because it's comfortable.

JAD: So clearly, these worms are in the feces that are landing near the tree that are somehow getting into people's feet the next time they come to use the tree. But no one intentionally steps in their own—you know, no one does that. Which meant ...

DICKSON DESPOMMIER: Oh, my goodness. Oh, my goodness, it can crawl, right? So let's find out how far it can crawl.

JAD: So what they did, these researchers, is they built a sandbox, and then they took some hookworm-infested stool ...

DICKSON DESPOMMIER: And put it right in the middle. Then every day, we'll sample from the stool sample out in the sand in all directions and find larvae and find out how far they can travel. How's that sound? So now we have larvae in the stool, and they began to crawl away from the stool, seeking a victim. On day one, they crawled an entire foot in all directions. But they weren't at two feet. On day two, my God, they're at two feet. At day three, they're at three feet! I can't believe this! They're crawling a long way. Day four, they crawl to four feet.

JAD: What about day five?

DICKSON DESPOMMIER: I'm allowed to ask that. And what about day five?

JAD: Five feet?

DICKSON DESPOMMIER: No.

JAD: No? Four feet.

DICKSON DESPOMMIER: That's it.

JAD: So after four feet, they're what, exhausted?

DICKSON DESPOMMIER: One would assume. On day six they were still at four feet. And on day seven, they were dead. So how in the world could you deal with this problem when these worms can crawl—they can crawl four feet. It doesn't matter where you defecate, they're gonna crawl away from that. And within a four-foot radius of that stool sample, you're gonna get hookworm. Unless you do something radical that's never been done before. They devised a scheme for burying the stool sample into the ground six feet deep.

JAD: Because if the worms can only make it four feet, well then that's two feet past the point where they die.

DICKSON DESPOMMIER: We call that the outhouse. [laughs] So the outhouse was invented by exploring the life cycle of hookworm. And in fact, Rockefeller got his wish. The South did rise again.

JAD: That sounds too easy to me, though. You're telling me that an understanding of hookworm, which created the outhouse, removed the, quote, "Southern laziness disease," and they did rise?

DICKSON DESPOMMIER: It did.

JAD: And you bring that all back to the hookworm?

DICKSON DESPOMMIER: I do.

JAD: Really?

DICKSON DESPOMMIER: No, I bring it back to sanitation.

JAD: Now to be fair, you can find plenty of other reasons why the South rose again.

ROBERT: Air conditioning and highways and universities and stuff like that.

JAD: Right. So the hookworm had some help. But what is clear is that when we as a country began to distance ourselves from our own excrement, to put it bluntly, when we stopped walking around in our own [bleep], there were all of these unintended consequences!

DICKSON DESPOMMIER: Salmonella disappeared. Eislitica disappeared. Shigella disappeared. Cholera disappeared. Giardia? Disappeared. Cryptosporidium. Anything that's associated with parasites in feces disappeared. Every time we built outhouses and people used them religiously, guess what? Their kids could stay in school longer. They could learn more. They got ahead faster.

JAD: DICKSON Despommier is a professor of public health in environmental health sciences and microbiology at Columbia University.

ROBERT: Can they make longer titles at that university?

JAD: [laughs] He literally wrote the book on parasites.

ROBERT: The book is called Parasitic Diseases. You know it very well. It's soon to be a major motion picture. It's now in its fourth edition.

JAD: In its fourth edition.

ROBERT: And while we're on the subject of hookworms and the glorious campaign to deworm America, because this has been a very carefully crafted and intentionally fair program ...

JAD: Mm-hmm?

ROBERT: ... you have heard the case against hookworms. Now let's turn the coin and say something nice about hookworms. And to begin that discussion, let's go to our reporter Patrick Walters. So Pat, are you there?

PAT WALTERS: Yeah, I'm here, Robert.

ROBERT: So tell us a little bit about this fellow. What's his name exactly?

PAT: His name is Jasper Lawrence.

JASPER LAWRENCE: That's right. Jasper Lawrence.

ROBERT: So where is he from?

PAT: He actually grew up in England. He grew up in this little farm in the southwest corner of England. And it's important to know, I think, before hearing any part of his story, that Jasper has had allergies for pretty much his whole life.

JASPER LAWRENCE: On really bad days, my eyes would swell up so much from pollen or airborne allergens that they would feel like they were swelling shut. I could feel my eyes squeaking in my sockets. It was an enormously uncomfortable feeling.

PAT: But it was nothing debilitating.

JASPER LAWRENCE: They were just allergies.

PAT: So, you know, he just, like most other people with allergies, just learned to deal with it.

JASPER LAWRENCE: You know, you live with it. But what changed for me in my late 20s, early 30s was my asthma. And at that time, I was living in Santa Cruz. I was relatively recently married. We had three cats that had been grandfathered in with the relationship, and I started a landscaping business. I really didn't want to work for someone else.

PAT: Like, someone with allergies starting a landscaping business. That seems kind of unexpected.

JASPER LAWRENCE: 'Stupid' is actually the word for it. And within six months or a year ...

PAT: He starts to notice ...

JASPER LAWRENCE: This really weird barking cough.

PAT: Was there anything particular that brought this on?

JASPER LAWRENCE: No, it was just sitting and breathing. Cats certainly didn't help.

PAT: Right.

JASPER LAWRENCE: And during that period, my asthma got much worse very, very quickly. By the time it was 1996,1997, I was seeing specialists, having skin allergen tests and cycling through emergency inhalers, trying Cingulair and all these other drugs that were coming on the market. I was being hospitalized at least a couple of times a year. I mean, I looked terrible. I had dark eyes and pale, waxy skin. I had that allergic look. It was a really bad time.

PAT: And he decides in the summer of 2004 to take a vacation.

PAT: You made this visit to England?

JASPER LAWRENCE: Yeah. I took my two daughters back to see my aunt who had raised me. Very early in the visit, I was sitting at her kitchen table, and she asked me if I'd seen a BBC documentary about parasites and their connection with things like asthma and allergies, multiple sclerosis. And of course, I hadn't, but I went upstairs and got on the internet after lunch, and I stayed on the internet until perhaps two in the morning. I didn't stop.

PAT: And he's reading and reading.

JASPER LAWRENCE: The work of all these researchers.

PAT: One study after the next

JASPER LAWRENCE: Japan. Epidemiological studies in Africa. Animal models of multiple sclerosis. This enormous weight of evidence.

PAT: That in the developing world, people don't really have asthma or allergies. And what he discovers is that behind all of this, to his shock, is hookworms.

ROBERT: Hookworm?

PAT: Yeah, hookworms.

JASPER LAWRENCE: Yeah. I learned that asthma was 50 percent less likely in someone who had a hookworm infection.

PAT: So this sort of just, like, hits you?

JASPER LAWRENCE: Oh, yeah.

PAT: What did you think when you—when you read that?

JASPER LAWRENCE: Oh, I immediately was determined to obtain hookworm immediately. I couldn't wait.

PAT: So hookworms are these very tiny worms, the size of a little hair. But if you take a microscope and you zoom way in, they have this big circular mouth brimming full of pointy teeth.

ROBERT: Eww!

PAT: Very scary to look at. They have these toothy mouths so that they can burrow up through your feet, ride through your blood, and eventually end up down in your gut and start chewing on the inside of your intestines.

ROBERT: This guy wants hookworms in his intestines?

PAT: Absolutely.

PAT: And so did you just google it?

JASPER LAWRENCE: Yeah, hookworms for sale. I mean, you know, someone's gotta be selling them.

PAT: But ...

JASPER LAWRENCE: Nothing. I contacted every laboratory supply company in the world, and parasitology research centers. And they all said the same thing. No. Various flavors of 'No.' And so I came to the conclusion that I was gonna have to go to the tropics.

PAT: So fast forward a little. Jasper is in Cameroon, along the coast.

JASPER LAWRENCE: Quite literally and figuratively, the armpit of Africa.

PAT: He's 200 miles north of the equator. It's extremely hot. He finds a guy to drive him around. And so he and his driver would go to a village.

JASPER LAWRENCE: He'd get out of the car.

PAT: Walk up to these villagers, and ask them if they could see the latrine.

JASPER LAWRENCE: Just an open area of ground, usually with bushes so people can have a little bit of privacy. And I would go over to the area, remove my shoes and start walking. The first time I did that, I almost couldn't do it. It must have been 110 degrees that day, 100 percent humidity. And the stench and the noise from the insects, it was so repulsive and so disgusting.

PAT: How many villages' latrines do you think you visited?

JASPER LAWRENCE: Between 30 and 40.

PAT: Jasper spent two weeks there, walking around in village latrines. And then he flew home.

ROBERT: Hmm.

JASPER LAWRENCE: And I got back from Africa in early February. So I was looking at allergy season coming up. And the day I realized that I'd no longer had allergies, it was such a good day. I got into my car and I started driving, and I had the window down. You know, I felt the breeze blowing across my face. In the past, what that meant was that very quickly my eyes would be itching uncontrollably. Snot and phlegm was gonna be pouring out of every orifice in my face. And it didn't happen. It didn't happen. I just started screaming in the car. I was so, so happy. And I haven't had an asthma attack since I went to Africa. I no longer have allergies. The vast majority of the benefit that I've experienced has come from hookworm.

ROBERT: What is the hookworm doing, do you know?

PAT: Well, so the immune system that we learn about in elementary school is all about, like, these attack cells that go after foreign invaders and destroy them.

ROBERT: Right.

PAT: And that's a big important part of the immune system. But if the immune system were allowed to attack and destroy things unchecked it could kill you. And there are lots of diseases where the primary symptoms are caused by the immune system attacking the body that it's really designed to protect. Allergies and asthma are just two of these. Some of the more serious ones are like type one diabetes, multiple sclerosis, Crohn's disease, in which the immune system actually starts attacking the inside of the intestines. There are like 80 of these diseases.

ROBERT: 80 of them.

PAT: And so what scientists have found in lots and lots of mouse studies and in some human studies to this point, too, is that once the hookworms get inside the gut and the immune system actually starts attacking, somehow hookworms actually stimulate these cells, which just quiet things down and tell the attack cells to stop attacking.

ROBERT: So these are like lullaby cells.

PAT: Exactly. What lots and lots of scientists think ...

JOEL WEINSTOCK: Joel Weinstock. Tufts Medical Center.

PAT: ... and dozens of others, is that over ...

JOEL WEINSTOCK: Thousands and thousands of years ...

PAT: Hookworms almost developed in tandem with the human immune system.

JOEL WEINSTOCK: Coevolution. Parasites living within your body, your immune system changes.

PAT: If you got to a point where the hookworms could survive safely...

JOEL WEINSTOCK: Worm gets a home. There's food coming down the food pipe. And in return ...

PAT: The human immune system gained some kind of ...

JOEL WEINSTOCK: Some form of ...

PAT: ... positive regulatory ...

JOEL WEINSTOCK: ... advantage.

PAT: So that if you had this glitch where your immune system started attacking your own body, the presence of the hookworms would keep things ...

JOEL WEINSTOCK: Controlled. And that's the gift. You do something for the worm, the worm does something for you.

ROBERT: So then, by that logic, what we in the West, in the richer countries, have done stupidly, is we have cleaned ourselves up too much and we don't have enough wormies in us.

PAT: Yeah, this is called ...

JOEL WEINSTOCK: They call it the hygiene hypothesis.

ROBERT: The hygiene hypothesis. That we are not dirty enough.

PAT: Too clean.

JASPER LAWRENCE: We function like rainforests. We're ecosystems, and we've entirely eliminated a class of organism that co-evolved with us and our genetic predecessors for millions of years.

JOEL WEINSTOCK: Now I don't want to leave the impression that hygiene is bad for you. People can't go back to living in filth, kids playing in sewage by the riverbank. But in improving our hygiene, we are also excluding organisms that may be important from making us well.

ROBERT: So then what does Jasper do about all this?

PAT: He decides to start a business selling hookworm to people.

ROBERT: What?

PAT: You can call him up and he will literally FedEx a dose of hookworms to your door.

ROBERT: How?

JAD: Sorry to break in for a second. Pat?

PAT: Hi, Jad.

JAD: Where does he get the hookworm from?

PAT: This is weird. Jasper gets the hookworm from himself.

PAT: Could you describe how you go about getting hookworm from your stool into one of your patients?

JASPER LAWRENCE: Well, it's a very easy organism to work with. It just gets up and it walks out of it. So it doesn't take an enormous amount of work to separate it from the feces. And then having done that, I repeatedly wash them in solutions of antibiotics to make sure that anything that could live on them is killed. People contact us, we'll have them complete a questionnaire, submit a recent blood test, then we'll ship them a dose and all the materials and equipment and the instructions necessary to infect themselves.

ROBERT: Is this a safe thing to do?

PAT: Jasper has done tons and tons of research, but he's not a doctor.

ROBERT: Right.

PAT: The treatment is not approved by the FDA.

ROBERT: That's what I wonder. Is there any serious sort of double blind study trying to figure out whether some safe delivery of hookworm might make sense?

PAT: Yeah. So one of the guys who was sort of a pioneer in this hookworm research is David Pritchard.

DAVID PRITCHARD: I'm Professor David Pritchard.

PAT: Immunologist and parasitologist.

DAVID PRITCHARD: At the University of Nottingham, where I study parasites and the wound-healing properties of maggots. So we've now got two safety trials under our belts, but we've yet to conduct the trials to show that therapeutic benefit results from infection with worms.

PAT: So Pritchard infected himself pretty much just to make sure that it was safe.

DAVID PRITCHARD: What we did was 10 of us in the lab took worms at different doses. We were either given 10, 25, 50 or 100 worms, and then we had to report on the symptoms. And on the back of that study, we determined that 10 worms were tolerated.

PAT: But Pritchard, when he did this proof-of-safety study, actually gave himself 50 hookworms.

ROBERT: Oh!

PAT: Which put him out of commission for a while.

DAVID PRITCHARD: Well, I felt pretty bad. I mean, pain in the gut, really. You know, you could feel them because they are biting on your tissues.

PAT: I mean, if you have too many hookworms, they can cause things like diarrhea. And the most serious side effect, and the side effect that makes them sort of a public health enemy is that they can give you anemia.

DAVID PRITCHARD: So if you have too many, you lose quite a bit of blood to these parasites.

JASPER LAWRENCE: Well, you know, if you take too many hookworm, which you're not gonna if you come to us, the worst thing you're gonna get is anemia. But it's not like you wake up one morning and you're drained of blood. Very slow to develop, and it's very easy to deal with.

PAT: Jasper's kind of just gone for it. You know, it's a very sort of like, cowboy move.

JASPER LAWRENCE: To the scientific community, I think they believe that I'm premature ...

JOEL WEINSTOCK: It's not FDA approved.

JASPER LAWRENCE: ... in offering this to the public.

JOEL WEINSTOCK: You don't know what it is. You don't know its purity. It's not safe.

PAT: But I've talked to several clients who had really severe allergies and asthma. They say they've just achieved these great results. And Jasper also says he's seen success with a few multiple sclerosis patients and several Crohn's disease patients, too.

PAT: Like, how many people do you think that you have infected?

JASPER LAWRENCE: It's about 85 right now.

PAT: How is business? Is it everything that ...

JASPER LAWRENCE: Business is adequate, but I honestly don't know why I don't wake up in the morning with my front garden 20 deep with people with ulcerative colitis, Crohn's disease, allergies. I just don't know why I'm not completely buried.

PAT: The way he sees it, people are scared.

JASPER LAWRENCE: Well, they're the people who are coming from a point of view of what they learned in kindergarten about clean drinking water and sewers. To them, worms and parasites are so repulsive that there's nothing good to be said about them. But I can make you better. It's simple. It's cheap. I mean, for God's sake, these organisms fall out my rear end every day a half a million at a time. The raw material is human excrement, for God's sake. All people have to do is open their minds. Are you really that scared of a little worm?

ROBERT: Thanks to reporter Pat Walters.

JAD: Thanks, Pat!

ROBERT: And to Jasper Lawrence.

JAD: And to the worms!

ROBERT: And to the hookworms. Thank you, hookworms.

JAD: Thank you, hookworms.

ROBERT: More information about hookworms on our website. And that's the end of this section.

JAD: What, don't you want to say the address? Radiolab.org.

ROBERT: Yes.

JAD: Slash hookworm. No, just.org. Radiolab will continue in a moment.

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