
For most of human history, people went about their daily lives with a worm or two (or fifty) in their guts. Only in the past century, with pharmaceuticals and sanitation practices, have we made significant strides towards deworming the whole of humanity. And that’s typically been thought of as a good thing, because having too many worms in your body can–quite literally–suck the life out of you. But is it possible to have… too few worms? Science wonders if deworming ourselves has actually led to an increase in certain chronic diseases. On this episode, we dive into Necator americanus, a.k.a. the American Hookworm, and its mysterious relationship with each of us. We trace the hookworm’s 118-year journey from a demonized economic depressant, to its use as a desperate D.I.Y. immunosuppressant, to its potential as a medical treatment for a number of chronic diseases, everything from asthma to MS. We’re bringing back two stories from our 2009 episode Parasites plus new research on ho...
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Latif Nasser
Hey, I'm Latif Nasser.
Molly Webster
Hi, I'm Molly Webster and this is Radiolab.
Latif Nasser
And what are we doing today, Molly?
Molly Webster
Okay, well, Latif, remember back in 2009, before you and I both worked at the show, there was an episode called Parasites.
Latif Nasser
Oh, my God. Love that episode.
Molly Webster
It is really one of my favorites. And in that episode, we talk about this tiny, maybe creepy little worm called a hookworm.
Latif Nasser
That's right.
Molly Webster
You remember it?
Latif Nasser
Yeah, I mean, like, it hooked into my brain. Like the.
Molly Webster
The hookworm hooked into your brain.
Latif Nasser
It's the story of that one guy. And then there's the final scene where he's walking through the.
Molly Webster
Oh, wait, okay, wait, wait, wait. You don't actually have to tell. Don't. Don't say what the final scene is, is, because what we're going to do here is I'm going to play this the hookworms chunk of that episode, and then I have an update a 20 year later hookworm and human medical update
Latif Nasser
VH1 behind the Music. Where is the hookworm now?
Jad Abumrad
Yes.
Molly Webster
Where is the hookworm? And where is the human.
Latif Nasser
Okay, great.
Molly Webster
This whole episode, it introduced this idea that this thing that we think is like the biggest, scariest, grossest pest of all time, maybe they're not as gross as you think. And now 20 years later, people are saying maybe they're really not as gross as you think.
Latif Nasser
Love it.
Molly Webster
And there's just like, all this cool new research about hookworms in the human body and specifically one very important type of disease, Autoimmune disorders.
Dr. Paul Giacoman
Ooh.
Latif Nasser
That, as you know, is one I'm particularly interested in, but. Well, yeah, I'm sold. I would like to hear more.
Molly Webster
Okay, great. So I'm gonna play the original hookworm segment just so we all know what's going on, and then we'll jump into an Update in about 20 minutes.
Latif Nasser
Okay, great. Wait, you're listening.
Jasper Lawrence
Okay.
Pat Walters
All right.
Molly Webster
Okay.
Jad Abumrad
All right.
Molly Webster
You're listening to Radiolab.
Pat Walters
Radiolab from wnyc.
Molly Webster
Rewind.
Jad Abumrad
Hello, I'm Jad Abumra.
Robert Krulwich
And I'm Robert Krilwich.
Jad Abumrad
This is Radiolab. Our topic today, parasites. Parasites.
Robert Krulwich
Now, we've met them, they're nice, and we've met them when they're not so nice.
Jad Abumrad
I don't know that we've met any nice ones, really.
Robert Krulwich
Oh, we haven't. I thought that. Oh, they're those flukes.
Jad Abumrad
They were pretty nice. Yeah, they were nice.
Robert Krulwich
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 invisible. Invisible and sort of offstage.
Jad Abumrad
Yeah.
Robert Krulwich
But when you back off a little bit and consider them, you know, in the effects that they have on the
Jad Abumrad
world, they're actually these powerful sculptors of monumental narrative.
Robert Krulwich
In other words, these are little guys telling very big stories.
Jad Abumrad
In fact, here's an example. Recently I went to visit a guy named Dixon Despamier, but Columbia University, he's a parasitologist and, well, he does a bunch of different things. We ended up talking about. Well, he told me this crazy story.
Molly Webster
Okay, Molly, jumping in here really quick. This next part of the story which has to do with Rockefeller, think of it like those stories that has been told so many times. It starts to become like a tall tale. It's a living myth. So the facts are a little blurry, but the idea is right. Here we go.
Unknown Rockefeller Commission Member
The story I love telling the most is how we eradicated hookworm.
Jad Abumrad
The story begins in 1908.
Unknown Rockefeller Commission Member
John D. Rockefeller, Sr. Really Rich Guy,
Jad Abumrad
is sitting in his New York office
Unknown Rockefeller Commission Member
and he's thinking, how can I make more money selling something to the South?
Jad Abumrad
Yeah. I've got all this money, got all these resources. I just need a new market. In terms of new markets, the south was pretty much untapped. If only those damn Southerners would just
Unknown Rockefeller Commission Member
get off their butts and get going.
Jad Abumrad
Problem was, they weren't. They weren't getting off their butts.
Unknown Rockefeller Commission Member
The farms were not operational. The economic engine was turned off.
Jad Abumrad
The economy was in the toilet. And so John D. Rockefeller wanted to know why. Why aren't they producing more?
Unknown Rockefeller Commission Member
Yep. What's happened to their economic engine? So he thought, I know, I'll form a commission.
Jad Abumrad
Yeah.
Unknown Rockefeller Commission Member
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. We don't exactly know what's wrong, but we think that these people are sick from something because they don't. They don't behave like we do.
Jad Abumrad
What does that mean?
Unknown Rockefeller Commission Member
They are slow. Not mentally. They're slow physically. They're pale. I'll give you an example. Remember the movie Deliverance?
Jad Abumrad
Sure.
Unknown Rockefeller Commission Member
Okay. Remember that little guy that played the banjo?
Jad Abumrad
I remember the other scene that we all read. We're not gonna talk about that.
Unknown Rockefeller Commission Member
No, we're not. No, we're not. But if you can recall what that little banjo player looked like. Little wiry looking guy.
Jad Abumrad
But he looked old, sickly pale.
Unknown Rockefeller Commission Member
Yeah, sickly pale and yet an adult.
Robert Krulwich
Well, wait a second, wait a second. That is not a description of all Southerners. No description of one teeny corner in a.
Jad Abumrad
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 look weak. They looked wan. They looked kind of wan. Wan, wan, wan. They were wan, Pale, lethargic.
Robert Krulwich
It's interesting. Wan or wan, wan.
Joel Weinstock
Yoochoo.
Jad Abumrad
So the thought was that maybe these Southerners had some kind of laziness to. 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.
Unknown Rockefeller Commission Member
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 Abumrad
Next thing you know, Rockefeller puts together another commission to find out what the
Unknown Rockefeller Commission Member
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 Abumrad
And this seemed to be a clue. The incidence of anemia was linked somehow to the soil.
Unknown Rockefeller Commission Member
Maybe.
Jad Abumrad
Bum, bum, bum.
Pat Walters
Yes.
Jad Abumrad
Something was in the soil.
Unknown Rockefeller Commission Member
That's correct. So somehow they hit upon this idea of looking for a hookworm.
Jad Abumrad
The hookworm.
Unknown Rockefeller Commission Member
The hookworm.
Jad Abumrad
So they thought, all right, let's run some tests.
Unknown Rockefeller Commission Member
And when they did big time, they discovered hookworm. Big time. So the anemia is due to hookworm.
Jad Abumrad
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? Most of them said something like this,
Unknown Rockefeller Commission Member
and 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 Abumrad
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.
Unknown Rockefeller Commission Member
Barefoot, just like everybody else, because it's comfortable.
Jad Abumrad
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.
Unknown Rockefeller Commission Member
Which meant, oh my goodness. Oh my goodness. It can crawl, right? So let's find out how far it can crawl.
Jad Abumrad
So what they did, these researchers, is they built a sandbox and then they took some hookworm infested stool and put
Unknown Rockefeller Commission Member
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 try 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 2ft on day two. My God, they're at 2ft. At day three, they're at 3ft. I can't believe this. They're crawling a long way. Day four, they crawl to four feet.
Jad Abumrad
What about day five?
Unknown Rockefeller Commission Member
I'm allowed to ask that. And what about day five?
Jad Abumrad
Five feet? No, no, four feet.
Unknown Rockefeller Commission Member
That's it. 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 going to crawl away from that. And within a four foot radius of that stool sample, you're going to 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 Abumrad
Because if the worms can only make it four feet, well, then that's two feet past the point where they die.
Unknown Rockefeller Commission Member
We call that the outhouse. And in fact, Rockefeller got his wish. The south did rise again.
Jad Abumrad
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.
Unknown Rockefeller Commission Member
It did.
Jad Abumrad
And you bring that all back to the hookworm?
Unknown Rockefeller Commission Member
I do.
Molly Webster
Really?
Unknown Rockefeller Commission Member
No, I bring it back to sanitation.
Jad Abumrad
Now, to be fair, you can find plenty of other reasons why the south rose again.
Robert Krulwich
Air conditioning and highways and universities and stuff like that.
Jad Abumrad
So the hookworm had some. 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, there were all of these unintended consequences.
Unknown Rockefeller Commission Member
Salmonella Disappeared. Izlitica, disappeared. Shigella disappeared. Cholera, disappeared. Giardia, disappeared. Cryptosporidium. Anything that's associated with parasites and feces disappeared. Every time we build out houses and people use them religiously, guess what? Their kids could stay in school longer. They could learn more. They got ahead faster.
Jad Abumrad
Dixon Dasvamier is a professor of public health in environmental health sciences and microbiology at Columbia University.
Robert Krulwich
Can they make longer titles at that university?
Jad Abumrad
He literally wrote the book on parasites.
Robert Krulwich
The book is called Parasitic Diseases. You know it very well, and it's soon to be a major motion picture, but now in its fourth edition.
Jad Abumrad
In its fourth edition.
Robert Krulwich
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, 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 Krulwich
So tell us a little bit about this fellow. What's his name exactly?
Pat Walters
His name is Jasper Lawrence.
Jasper Lawrence
That's right, Jasper Lawrence.
Robert Krulwich
So where is he from?
Pat Walters
He actually grew up in England. He grew up in this little farm in the southwest corner of England. 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, but
Pat Walters
it was nothing debilitating.
Jasper Lawrence
They were just allergies.
Pat Walters
So, you know, he's just like most other people have allergies. Just learn to deal with it, you
Jasper Lawrence
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 anymore.
Pat Walters
I was thinking 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, he starts to notice this really weird barking cough.
Pat Walters
Was there anything particular that brought this on?
Jasper Lawrence
No, it was just sitting and breathing. Cats certainly didn't help. 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 Singulair 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 Walters
And he decides in the summer of 2004 to take a vacation. 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 Walters
And he's reading and reading.
Jasper Lawrence
And the work of all these researchers,
Pat Walters
one study after the next, Japan, epidemiological
Jasper Lawrence
studies in Africa, animal models of multiple sclerosis. This enormous weight
Pat Walters
of evidence 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 Krulwich
Hookworm? Yeah.
Jasper Lawrence
Hookworms, Yeah. I learned that asthma was 50% less likely in someone who had a hookworm infection.
Pat Walters
So this sort of just like, hits you.
Jasper Lawrence
Oh, yeah.
Pat Walters
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 Walters
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. 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 Krulwich
This guy wants hookworms in his intestines?
Pat Walters
Absolutely. And so you just Google it.
Robert Krulwich
Yeah.
Jasper Lawrence
Hookworms for sale. I mean, you know, someone's gotta be selling them, but not nothing. I contacted every laboratory supply company in the world and parasitology research centers, and they all said the same thing, various flavors of no. And so I came to the conclusion that I was going to have to go to the tropics.
Pat Walters
So fast forward a little. Jasper is in Cameroon, along the coast,
Jasper Lawrence
quite literally and figuratively the armpit of Africa.
Pat Walters
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, get out of the car, 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. Must have been 110 degrees that day. 100% humidity. And the stench and the noise from the insects, it was so repulsive and so disgusting.
Pat Walters
How many villages of latrines do you think you visited?
Jasper Lawrence
Between 30 and 40.
Pat Walters
Jasper spent two weeks. They're walking around in village latrines, and then he flew home.
Jasper Lawrence
I got back from Africa in early February, so I was looking at allergy season coming up. And the day I realized that I no longer had allergies, that 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.
Molly Webster
A word up. Word up. Word.
Jad Abumrad
A word.
Jasper Lawrence
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 Krulwich
What is the hookworm doing? Do you know?
Pat Walters
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. 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 1 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 Krulwich
80 of them.
Pat Walters
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
Unknown Rockefeller Commission Member
which
Pat Walters
just quiet things down and tell the attack cells to stop attacking.
Robert Krulwich
So these are like lullaby cells.
Pat Walters
Exactly. What lots and lots of scientists think,
Joel Weinstock
Joel Weinstock, Joel Weinstock Tufts Medical center
Pat Walters
and dozens of others, is that over
Joel Weinstock
thousands and thousands of years, hookworms almost
Pat Walters
developed in tandem with the human immune system.
Joel Weinstock
Coevolution parasites living within your body. Your immune system changes.
Pat Walters
So 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.
Pat Walters
And in return, the human immune system gained some kind of, some form of positive regulatory advantage. So that if you had this glitch where your immune system started attacking your own body, the presence of the hookworms would keep things controlled.
Joel Weinstock
That's the gift. You do something for the worm, the worm does something for you.
Robert Krulwich
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.
Joel Weinstock
Yeah, this is called, they call it the hygiene hypothesis.
Robert Krulwich
The hygiene hypothesis that we are not dirty enough.
Pat Walters
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 now.
Joel Weinstock
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 for making us well.
Robert Krulwich
So then what does Jasper do about all this?
Pat Walters
He decides to start a business selling hookworm to people.
Jad Abumrad
What?
Pat Walters
You can call him up and he will literally FedEx a dose of hookworms to your door.
Robert Krulwich
How.
Jad Abumrad
Sorry to break in for a second, Pat.
Pat Walters
Hi, Jad.
Jad Abumrad
Where does he get the hookworm from?
Pat Walters
This is weird. Jasper gets the hookworm from himself. 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, it 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 Krulwich
Is this a safe thing to do, to suggest Jasper?
Pat Walters
Jasper has done tons and tons of research, but he's not a doctor. The treatment is not approved by the fda.
Robert Krulwich
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 Walters
Yeah. So one of the guys who was sort of a pioneer in this hookworm research is David Pritchard. I'm Professor David Pritchard, 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 worm.
Pat Walters
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 Walters
But Pritchard, when he did this proof of safety study, actually gave himself 50 hookworms.
Latif Nasser
Oh.
Pat Walters
Which put him out of commission for a while.
David Pritchard
Well, I felt pretty bad. I mean, pain in the gut, really. You could feel them because they are biting on your tissues.
Pat Walters
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 Walters
Jasper's kind of just gone for it. You know, it's a very sort of
Jasper Lawrence
like, cowboy move 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, you
Joel Weinstock
don't know what it is. You don't know its purity. It's not safe.
Pat Walters
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. Like, how many people do you think that you have infected?
Jasper Lawrence
It's about 85 right now.
Pat Walters
How is business?
Jasper Lawrence
Is it everything? That 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 Walters
The way he sees it, people are scared.
Jasper Lawrence
Well, there are 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?
Latif Nasser
Okay, okay, okay, okay.
Molly Webster
So, okay, so that's it.
Latif Nasser
So, so, wait.
Dr. Paul Giacoman
But.
Molly Webster
Okay, yeah, maybe the. Maybe the question is, Latif, you have talked about this on the show. You have an autoimmune disorder.
Latif Nasser
Yes.
Molly Webster
Crohn's disease.
Latif Nasser
Crohn's disease.
Molly Webster
Okay, you've heard this piece. Are you scared of a little worm?
Latif Nasser
I mean, I am intrigued. I don't know whether to be scared. If there are clinical trials that can help tell me whether to be scared or not of this worm. That's what I want to know.
Molly Webster
All right, well, then I am going to tell you about a clinical trial, and then you can tell me what you think. But after the break, all right.
Latif Nasser
Oh, after the break. All right, after the break. Let's do it.
Molly Webster
Clinical trial.
Latif Nasser
I'm ready. I'm excited.
Molly Webster
Okay, great. Latif, we are back from break, and we left you at Are you scared of a little worm?
Latif Nasser
And I was like, maybe. Maybe. I don't know. Let's do some actual clinical trials.
Molly Webster
And that is what, like, okay, so that episode was done in 2009.
Latif Nasser
Right.
Molly Webster
And so I want to fast forward to today. There have been a number of clinical trials.
Pat Walters
Oh, it's so exciting.
Latif Nasser
Okay, so what happened?
Molly Webster
Okay, so. Hi.
Dr. Paul Giacoman
Hey, how are you? I talked to this researcher, Dr. Paul Giacoman. Paul Jackman, senior research fellow at the Australian Institute of Tropical Health and Medicine.
Molly Webster
And he's basically trying to do, like, the next iteration of Jasper. Of, like, Jasper, but, like, With. With actual scientific studies and stuff.
Dr. Paul Giacoman
Okay. Yeah, yeah. Trying to understand the potential beneficial effects of worms in people.
Molly Webster
So one of the things that he's been studying is treating people who are
Dr. Paul Giacoman
at risk of type 2 diabetes with hookworms.
Molly Webster
So type 2 diabetes, that's the diabetes you typically. Later in life.
Latif Nasser
Yeah.
Molly Webster
What made you pick diabetes?
Dr. Paul Giacoman
It sort of came on the back of research, which started in the 2010s, where people went into regions of the world where parasitic worms are really common.
Molly Webster
And what they found is that there is a correlation between something like type 2 diabetes and the presence or lack of worms.
Latif Nasser
Huh.
Dr. Paul Giacoman
Yeah. So basically.
Molly Webster
So what Paul and his team did is basically they took people who are at risk for type 2 diabetes and they gave them hookworms.
Latif Nasser
How do they give it to them? How do they take them? Do you, like, slurp it down like a little piece of spaghetti?
Molly Webster
No.
Dr. Paul Giacoman
You know, people think where they're going to enroll, they're going to have to swallow a worm or swallow worm eggs, et cetera.
Molly Webster
So it's actually much worse.
Jad Abumrad
I don't know.
Molly Webster
It could be much better than that.
Dr. Paul Giacoman
Basically, in order to do our research,
Molly Webster
the first step of the process is they have folks who work in their lab, these.
Dr. Paul Giacoman
What called worm farms, volunteers who've consented to have a small number of worms
Molly Webster
living inside of them.
Latif Nasser
Oh, wow.
Dr. Paul Giacoman
Yes, exactly. The only way, you can't culture them, you can't just get them and freeze them.
Molly Webster
Really?
Dr. Paul Giacoman
Yeah. So basically, that's one of the limitations about working with these worms. You actually have to maintain. We call them worm farms.
Latif Nasser
So, like, hazard pay for that? Like, do they get a bonus?
Molly Webster
No, I think they're just very generous
Dr. Paul Giacoman
volunteers, brave and dedicated volunteers. And so that if we want to do our research, we say, hey, generous
Molly Webster
volunteer, can you give me a sample of your stool?
Latif Nasser
Okay.
Molly Webster
Because what happens in these people in the worm farms is the hookworms inside
Dr. Paul Giacoman
of them will mate and they can produce. The females can produce tens of thousands of eggs every day, which are released eventually in the poo.
Latif Nasser
Huh.
Molly Webster
And so they poop.
Dr. Paul Giacoman
We get the poo sample, add charcoal to it, which reduces the smell, and then we spread it onto the petri dish.
Molly Webster
They leave the petri dish in sort of like kind of a humid tropical environment.
Latif Nasser
Okay.
Molly Webster
It sits there for a week, and
Dr. Paul Giacoman
over the course of that, these tiny
Molly Webster
hookworm eggs start to hatch. And emerging from them are these microscopic,
Dr. Paul Giacoman
teeny, tiny baby worms, barely visible to the naked eye.
Molly Webster
And very quickly, Paul and his team
Dr. Paul Giacoman
hit them with, like, a Strong disinfectant to clean them. Then we can basically look down the microscope. We just, one by one, pick the wriggly worms, put them into a little
Molly Webster
tube, and then what they do is they put the worms on a band aid, essentially, and they take that band A and they put it on the skin of the patients that are enrolled in the clinical trial.
David Pritchard
Oh.
Latif Nasser
But not even on a cut. Just anywhere on the skin.
Molly Webster
Just anywhere on the skin.
Dr. Paul Giacoman
And then we sort of sit with them for about five minutes because participants start to get this tingling sensation, because
Molly Webster
what happens is these baby worms on the band aid start to release an enzyme which degrade tissue, which basically melts your skin so that they can start to burrow into your skin. And as they enter your skin, then your skin just closes up behind them. The tunnel closes, and then the worm makes their way down through your skin into the lymphatics, your lymphatic system. So if you think of the inside of your body as a water park, as one does, the lymphatic system is like the laser.
Latif Nasser
Sure, yeah, yeah.
Molly Webster
So these baby hookworms go through the skin cells, fall into this, like, little lymphatic river, then they float along through your lymph system. I kind of maybe picture them with, I don't know, cozies of non alcoholic beer, because they are babies on their little tube.
Latif Nasser
That's funny.
Molly Webster
And they're floating downstream. They float along and they get to what is known as your lymphatic duct, which is kind of right by your collarbone. And once they get there, they get shot out of the lymph stream into your bloodstream.
Dr. Paul Giacoman
And once they've gone into the blood, they're cruising around like on a water slide.
Molly Webster
They go from your collarbone towards the center of your chest, where they catch this huge slide that sends them into your heart. And then your heart, thud, thud, thud, shoots them out onto another big slide. That slide starts splitting and branching and splitting and branching. And as it does, the slide is getting smaller and smaller and smaller until, yeah, these little baby worms get stuck. They get trapped inside a super tiny
Latif Nasser
blood vessel because they're too big.
Molly Webster
Yeah, they're too big for the blood vessel. So they get stuck there.
Dr. Paul Giacoman
Their journey ends.
Molly Webster
But Paul says that's their cue to again release an enzyme that starts to melt away the walls of the blood vessel.
Latif Nasser
Whoa.
Molly Webster
Just enough, they can wriggle their way through and then pop out on the other side of this blood vessel and into your lungs.
Dr. Paul Giacoman
And then what they do is they crawl. They crawl up through the lung, all the airways.
Molly Webster
Like a rock climber. Boop, boop, boop, boop, boop, boop, boop. Up your trachea so they're almost in your throat.
Dr. Paul Giacoman
And then unknowingly, one day you will
Molly Webster
cough, which will dislodge these worms from your trachea up into this little free space in your throat where I like to think that they will do a backwards somersault. And then after you cough, you usually swallow.
Dr. Paul Giacoman
So, yeah, you'll swallow them.
Molly Webster
You swallow the worms.
Latif Nasser
Oh, my God.
Molly Webster
At which point they will shoot down your esophagus into your stomach.
Latif Nasser
Oh, my God.
Molly Webster
And then once you.
Latif Nasser
Why wouldn't you. Oh, but it's like, why wouldn't you just feed it to people then? Like, why do this whole crazy.
Molly Webster
Well, because this whole process from skin to gut takes about two to three weeks. And during that process, the worm is maturing.
Latif Nasser
Got it.
Molly Webster
And so it's actually developing in such a way that it can survive in your stomach.
Latif Nasser
I see. So it's like this is how it develops.
Molly Webster
Exactly.
Dr. Paul Giacoman
So it's a really fascinating life cycle. They can survive the stomach acid and then they sort of make their home in the upper. Just beyond the stomach there, in their upper small intestine.
Molly Webster
And once they're in the small intestine,
Dr. Paul Giacoman
they've got these sort of quite violent looking teeth.
Molly Webster
They will bite and clamp onto you
Dr. Paul Giacoman
and they very fairly delicately just sort of suck the blood.
Molly Webster
And this is where something sort of amazing happens, which is for the next two weeks, your body's gonna have this really intense reaction. So where the worm is biting down on your intestinal wall, it's gonna get inflamed. There's like an open sore where the worm is sucking and your body is going to freak out and try and flush the hookworm out. So you're gonna have diarrhea, you're gonna feel sick, and then it's all gonna stop. You're gonna feel fine. And Paul says this is most likely because right around this time, the hookworm has reached full adulthood.
Dr. Paul Giacoman
And we've actually, in some of our clinical trials, have taken a camera and we've had a look in the gut at regions of the gut where the worm's been feeding. And, you know, there might be one little small red spot there where next to a worm, but everywhere else, I think there's this rapid healing. The worm might actually be releasing factors that promote, you know, wound healing, for example.
Molly Webster
Really?
Dr. Paul Giacoman
Yeah, absolutely. It's in their best interest to basically feed and heal. The wounds in their environment.
Molly Webster
So the really cool thing is, is that when this hookworm reaches adulthood and it's bit onto you and it's making this hole in your intestine, it can actually release a protein or maybe many proteins to heal the wound at the same time. So you're not left with this gaping wound in your stomach. And then it's also producing other proteins that are quieting the immune system.
Dr. Paul Giacoman
Because your immune system could, it could just unleash an enormous attack on these worms. But that would die.
Molly Webster
But obviously the worm does not want that. And so it has these little proteins that secrete that tells your immune system, shh, be quiet. And you heard about this in our last episode. And I think this is what Jasper also sort of suspected was happening. There was something overall from the hookworms quieting the immune system.
Latif Nasser
I feel like you've kind of reframed this whole thing for me. So now it's become less like a story of a human clinical trial and more of story of like Mission Impossible. On the, on a worm scale, like, I'm like, how can this thing like vault over this but then say the right words to this person that they'll leave them alone and then, and then climb up the da, da, da. And then it's like, it's crazy. And then use their little blaster to like melt this thing so they can walk through this wall. It's like crazy. It's like a crazy thing that they're doing.
Molly Webster
But here's the thing, Latif. When Paul and his team got to the end of this two year trial with people who were at risk for type 2 diabetes, the people who were
Dr. Paul Giacoman
treated with the hookworms had things like reduced blood glucose levels and they had dramatically reduced insulin resistance levels. Lost a little bit of weight.
Molly Webster
And some of these people who were considered pre diabetic were no longer pre diabetic.
Latif Nasser
Oh, wow. So some people were cured?
Molly Webster
Effectively, yeah, basically.
Dr. Paul Giacoman
Well, when you look at the placebo people who got no worms, they went
Molly Webster
on to continue having high insulin resistance, glucose, no weight loss.
Dr. Paul Giacoman
So it was really the first causal clinical evidence that the worms were having a benefit on metabolic health.
Molly Webster
Then at the end of the trial, the end of the two years, the people who had the hookworms inside of them, they have the option to just get rid of the worms. Like you can take an over the counter deworming medication and they'll be gone the next day. Paul says at the end of this two year study, almost everyone kept their worms.
Latif Nasser
Wow.
Dr. Paul Giacoman
They Were happy at the end. They wanted to basically live with their worms. They were happy with them. And this is universal. Every clinical trial, almost universally at the end of a clinical trial, people are happy with their worms.
Molly Webster
Do you think the happiness is emotional or do you think the happiness is like they actually feel different?
Dr. Paul Giacoman
Yeah, exactly. So there's two things. One of them, they might think, well, it's not doing them any harm, so let's just keep them. And the other thing is we've, you know, in our two most recent clinical trials, which were placebo controlled.
Molly Webster
So these trials were looking at Celiac's disease.
Latif Nasser
Yeah.
Dr. Paul Giacoman
We asked people to do a quality of life and mood and wellbeing survey. And in both clinical trials, we had this really interesting improvement in well being and mood and sleeping quality.
Molly Webster
Wait, really?
Dr. Paul Giacoman
That we saw in the people with the, with the worm treatment and the placebos. We didn't see it. I can't explain it. But, you know, the data was there and it's really compelling.
Molly Webster
And there is like, what a weird thing.
Unknown Rockefeller Commission Member
Right?
Molly Webster
I know. So one. Well, here's the thing. I'm going to break that down for you, which is like one of the things we're all talking about right now is our microbiome.
Jasper Lawrence
Right?
Molly Webster
Right. It's like, what is the tiny stuff living inside of us, like viruses and bacteria that's actually helping us?
Latif Nasser
Right.
Molly Webster
One of the things Paul's talking about is like, well, there's also a macrobiome.
Dr. Paul Giacoman
You know, the macrobiome organisms that you can see with your naked eye these worms that can, you know, somehow live for up to a decade or even longer within our gut. The immune system should really have recognized these worms and kicked them out because they're such a big insult on the body.
Molly Webster
But Paul says it could be that when these worms, when they reach adulthood in your gut, when they start making the proteins that quiet your immune system, that actually suppresses the immune system so the immune system doesn't kill it.
Latif Nasser
Yeah.
Molly Webster
And that also means that then the immune system is like, not reacting as strongly to some other things. So this is where the whole autoimmune thing gets into play. Because in autoimmune diseases, as you know, your own immune system is attacking you.
Latif Nasser
Right.
Molly Webster
And if you've got a worm inside of you telling the immune system like, hey, you can chill out. I'm kind of part of you, like, don't attack me.
Latif Nasser
Yeah, yeah, yeah. Yes.
Molly Webster
Then overall, it's just the immune system's not gonna attack you.
Latif Nasser
I just, you know, the thing that's really confusing to me is why we've
Molly Webster
left you more confused.
Latif Nasser
No, because like, why would, like, this is something that we need seemingly to regulate our own kind of internal army. Right. Like, it's like, why would we outsource this very crucial part of ourselves?
Molly Webster
Like, like, what do you mean outsource?
Latif Nasser
Like, outsource like the worms are not us. Like, like if they're, if they're helping
Molly Webster
regulate, we would, we would outsource it because they, because they're helping. Like, we would outsource it because it's beneficial. Like, you have to imagine, like we've been living with worms for millions of years.
Latif Nasser
Yeah.
Molly Webster
And so a worm got inside of us and we probably killed it. And then a worm got inside of us and it probably killed us. And then a worm got inside of us and it lasted a little longer and then we did or did not die. And it's like basically this long term dance between us and the worm.
Dr. Paul Giacoman
So there's this really interesting truce that's happened throughout evolution where the worm benefits and the host benefits.
Molly Webster
The worm benefits because it's getting a place to live and some juicy blood to eat for years. And then the host us benefits by not getting sick and dying.
Dr. Paul Giacoman
But also it's from the potential immune shaping and metabolic shaping powers of the worm.
Molly Webster
So Paul's lab has shown that people who are given hookworms have fewer symptoms associated with type 2 diabetes, celiac's disease. There's also other studies looking for benefits for people with multiple sclerosis, ulcerative colitis. That's where you get ulcers in your intestines, Crohn's disease, Latif. And in those studies, some people have gone into remission with worms. That's not Paul's lab, but that's other labs.
Latif Nasser
Yeah.
Dr. Paul Giacoman
And you know, if they're beneficial and you know, why not turn it into a treatment?
Molly Webster
But that's kind of the thing, which is that since 2009 when we did that Jasper story, even though there are all these studies showing that hookworms are beneficial, hookworms are still not used as a medication or as a treatment.
Dr. Paul Giacoman
Yes. There's a lot of hurdles for developing hookworms as a medicinal treatment.
Molly Webster
Everyone is kind of like, listen, there's so many reasons why people don't want worms. Like, they're kind of just gross.
Dr. Paul Giacoman
But also, I briefly mentioned before, you get the larvae out of people's poo. So making a medicinal product with standardization
Molly Webster
and decontamination, it's just really Hard.
Dr. Paul Giacoman
Exactly. So at this stage, it's probably never going to be a mainstream treatment.
Molly Webster
In fact, Jasper, who we had mentioned was selling worms. He and his wife actually fled the US because they were being investigated by the fda.
Latif Nasser
Wow.
Molly Webster
And so as an answer to this kind of problem of the live worm, what we're seeing is people like Paul, his team, other researchers, they're trying to develop the proteins hookworms produce to heal your gut or quiet your immune system. They're trying to take those proteins, make them in a lab, and then put them in a pill form. But no one knows what the timetable for that is. And so for now, you really are just stuck with having to get a hookworm.
Dr. Paul Giacoman
And there are some sort of more black market where people are actually selling them and you can buy them. But I wouldn't necessarily recommend that for people, partially for the reason, because you're paying money for something which hasn't really been rigorously tested and it hasn't gone through the regulatory processes that other medications need to go through.
Molly Webster
And so, yeah, that's where. That's where it's at.
Latif Nasser
Okay, but. Okay, I gotta go. But my last question is, Molly, should I get a worm?
Molly Webster
I mean, dude, if I was you and I was in pain, I would try and figure out how to get a worm or get into a clinical trial. Can you fly to Australia and get into one of Paul's?
Latif Nasser
I think that.
Molly Webster
I'll tell you the areas that they're doing it in. The big research areas are like the Netherlands, Australia, New Zealand. You got any trips there planned soon?
Latif Nasser
No, you know, just those lucky people over there that get worms, you know?
Molly Webster
Well, you know, you could always do what Jasper did, which is just go walk around in some poop and pick up, you know, hookworms plus roundworms plus tapeworms. You know, that's an option.
Latif Nasser
No, that's not. I'm not gonna. I'm not gonna roll in a human feces.
Molly Webster
That was a. That's a level of desperate you're not at.
Latif Nasser
That's not how desperate I am.
Molly Webster
Okay, well, Australia it is then. Okay, hitting stop.
Latif Nasser
Okay.
Molly Webster
Okay, hitting stop.
Latif Nasser
Okay. Thank you, Molly Webster for the update.
Molly Webster
You're welcome.
Latif Nasser
The update was produced by Matt Kilty with help from Rebecca Rand. It was edited by Arianne Wack and fact checked by Diane Kelly.
Molly Webster
And we want to thank Pat Walters, Jad Abumrad, Robert Kulwich, and the whole 2009 parasite team that put that episode together. If you want to listen to the entire parasite episode, you can go check it out on our website.
Latif Nasser
And for everything else, Radio Labby. Please subscribe to our totally FDA approved newsletter. All right, we'll be right back.
Molly Webster
In 20 years.
Latif Nasser
In 20 years.
Molly Webster
No, just next week.
Latif Nasser
Yeah, we'll catch you next week.
Molly Webster
Bye.
Gabby Santis
Hi, I'm Gabby. I'm from the Bay Area, California. And here are the staff credits. Radiolab is hosted by Lulu Miller and Latif Nasser. Soren Wheeler is our executive editor. Sarah Sandbach is our executive director. Our managing editor is Pat Walters. Dylan Keefe is our director of sound design. Our staff includes Jeremy Bloom, W. Harry Fortuna, David Gable, Maria Paz Gutierrez, Sindhu Nainasambandan, Matt Kielty, Mona Margauker, Alex Neeson, Sara Khari, Natalia Ramirez, Rebecca Rand, Anissa Vitce, Arian Wack, Molly Webster and Jessica Young, with help from Gabby Santis. Our fact checkers are Diane Kelly, Emily Krieger, Natalie Middleton, Angeli Mercado and Sophie Semay.
Latif Nasser
Hey, Radiolab. Michael, Tacoma, Washington Leadership support for Radiolab Science programming is provided by the Simons
Molly Webster
foundation and the John Templeton Foundation.
Latif Nasser
Foundational support for Radiolabs was provided by the Alfred P. Sloan Foundation.
This Radiolab episode, hosted by Molly Webster and Latif Nasser, revisits and radically updates the show's iconic 2009 exploration of hookworms. The episode delves into the surprising and evolving relationship between humans and hookworms: from Southern sloth stereotypes and public health campaigns to modern research suggesting hookworm infection could treat autoimmune, metabolic, and allergic diseases. With new insights from clinical trials and researchers on the cutting edge, the episode asks: should we start thinking of hookworms as friends rather than foes?
Origin Story and Eradication Efforts – 1900s South
Jasper Lawrence’s Self-Experiment and the Hygiene Hypothesis
Jasper’s "Cowboy" Approach vs. Rigorous Clinical Studies
Dr. Paul Giacoman and Contemporary Clinical Trials
Current Research: Dr. Paul Giacoman, (Australian Institute of Tropical Health and Medicine) runs clinical trials with carefully administered hookworm infections, exploring benefits for type 2 diabetes, celiac disease, and more.
Worm “Farming” and Administration:
Results:
Challenges to Mainstreaming
On Southern Stereotypes and Sanitation:
On the Hygiene Hypothesis:
On the Mutually Beneficial Evolution:
On Public Perception and Future Therapy:
Despite the promising science, self-infection remains risky, unregulated, and unapproved. If considering experimental therapies, seek out legitimate clinical trials rather than the black market, and be aware of both medical and ethical complexities.
For more context, check out Radiolab’s original 2009 “Parasites” episode, also available on their website.