Meet Your Parasites: Can They Help Heal Autoimmune Disorders?

Years after scientists first noticed that autoimmune disorders rise as our environment gets cleaner, a new generation of researchers is looking at parasites not as a scourge but as a possible cure.

One chilly November morning, I head south from San Diego in a bottom-tier rental car. As I drive, the radio announcer reviews some of the most recent drug violence in Tijuana, where I’m headed. More than this ongoing brutality, however, parasites occupy my mind—worms that migrate through flesh, burst into lungs, crawl down throats, and latch on to tender insides. Any traveler might fret over acquiring such hangers-on while abroad. But I’m heading to Mexico precisely to obtain not just one, but a colony. Today in Tijuana I’ll deliberately introduce the hookworm Necator americanus—the American murderer—into my body.

Scientists are of two minds about parasites these days. Some consider them evil incarnate, but others note that the majority of humans infected with parasites today—upward of 1.2 billion people—host worms with few apparent symptoms. This camp has begun to suspect that worms may, in fact, confer some benefits on their human hosts. That brings me to my motive: A large and growing body of science indicates that parasites may prevent allergies and autoimmune diseases. And I’ve got both.

When I was 11, my hair began falling out. A dermatologist diagnosed alopecia areata, an autoimmune disorder. My immune system, normally tasked with protecting against invaders, had inexplicably mistaken friend for foe and attacked my hair follicles. I also suffered from fairly severe asthma as a child, and food allergies to peanuts, sesame, and eggs. My alopecia advanced until, by age 16, not a single hair remained on my body.

The National Institutes of Health estimates that between 14.7 and 23.5 million Americans have an autoimmune disease, or 5 to 8 percent of the population. The American Autoimmune Related Diseases Association puts the number at more than double that—50 million Americans. In the United States, autoimmune disease ranks among the top 10 killers of women—roughly three-quarters of those afflicted with autoimmune disease are female.

These statistics apply to the richest countries in the early 21st century. But immune-mediated diseases weren’t always this prevalent. Early hints of immune dysfunction during the late 19th century notwithstanding, the allergy and asthma epidemics gained steam during the 1960s, accelerated through the 1980s, and then plateaued by the early 2000s. In that period, depending on the study and the population, you’ll find somewhere between a doubling and a tripling of asthma and allergies in the developed world.

Some autoimmune diseases show even more dramatic increases. A 2009 study found that the prevalence of undiagnosed celiac disease had increased more than fourfold since the mid-20th century. The incidence of multiple sclerosis has nearly tripled. And for some of these diseases, there’s no end in sight. The incidence of type 1 diabetes, which more than tripled during the late 20th century, is estimated to double again by 2020.

What has happened? In 2002, the French scientist Jean-François Bach published a seminal paper for anyone asking that question. The study, which appeared in The New England Journal of Medicine, had two graphs side by side, one showing the gradual decline since 1950 of once-common infectious diseases—hepatitis A, measles, mumps, and tuberculosis—next to another showing, over the same period, an increase of autoimmune and allergic disease in the developed world. Nearly everyone contracted mumps and measles in 1950. By 1980, almost no one did. Vaccines had almost eliminated both viruses. In an even shorter period—since 1970—new cases of hepatitis A infection fell to one-fifth their former level. And all the while, new cases of asthma, multiple sclerosis, and Crohn’s disease doubled, tripled, and quadrupled, respectively.

If you retrace your own lineage back a few generations, you’ll probably find hay fever and asthma lessening with each one. You (like me) may have lifelong asthma and food allergies, for example. Your parents, meanwhile, maybe had seasonal hay fever. But relatively few of your grandparents’ generation—or great-grandparents, as the case may be—suffered from sneezing or wheezing of any sort. This pattern likely relates not to new exposures, but to the removal of old ones—exposures of the sort still prevalent in many parts of the developing world.

You’ve probably heard peripherally about the many allergens, such as dust mites, peanuts, and tree pollen, which cause allergies. Maybe you’ve heard reference to the infections and toxic pollutants that provoke autoimmune disease. Without suggesting that these ideas are totally unfounded, here’s an alternative and much simpler model for engendering immune dysfunction: To produce these disorders, you don’t need to add something foreign to your body. All that’s necessary, in fact, is the removal of a single critical component of the immune system.

Immunologists learned this lesson from real-life case studies. In one early example, scientists at the Oregon Health Sciences University in Portland in 1982 described an infant who’d died from multiorgan autoimmune disease—type 1 diabetes, thyroiditis, eczema, diarrhea, and a self-destructive immune response to viral infection. Seventeen other male infants from the boy’s extended family had perished the same way, but no girls. These boys had apparently inherited a gene that precipitated an immune-system meltdown.

Two more decades passed before geneticists identified the culprit. The gene was named FOXP3. When switched on, FOXP3 changed how white blood cells operated, turning them from aggressors into peacekeepers. In the case of those boys, a spontaneous mutation had disabled the gene. As a result, they couldn’t restrain immune aggression. They went thermonuclear on invaders, causing severe collateral damage. And they couldn’t tolerate even their own tissues.

A growing body of research now supports the finding that, like those infants, we routinely fail to tolerate everything—innocuous proteins (allergies), our own tissues (autoimmune disease), and our commensal flora (inflammatory bowel disease)—because we’ve done environmentally what that mutation did genetically. By changing our inner ecology, we’ve hobbled the critical suppressor arm of our immune system.

And that brings us back to my impending experiment. I pull off the highway into a eucalyptus-lined parking lot where I’ll meet my hookworm donor, a medical school dropout named Garin Aglietti.

In brief, Aglietti’s story goes like this: In the 1990s, he developed psoriasis, an autoimmune disorder of the skin. He’d also suffered from asthma for most of his life. Mostly he fretted over the conditions known to accompany psoriasis, such as cardiovascular disease and autoimmune arthritis. All-too-frequent chest pains incited a cascade of worry. “I felt like it was killing me,” he tells me. “I was way too young to be getting chest wall pain.”

Allopathic medicine—also known as modern medicine—didn’t offer much by way of treatment. Then in the early 2000s, Aglietti heard about a Japanese scientist named Koichiro Fujita. Working in Borneo in the 1990s, a time when Japanese children seemed increasingly prone to developing eczema, Fujita had noticed that Bornean children had exquisite skin and no allergies. They also harbored plenty of parasites. Was there a link?

Back in Tokyo, Fujita took the extraordinary step of infecting himself with tapeworm. His hay fever cleared up. His skin became clearer and less muddled. He started preaching that the modern world was too clean for our
own good.

Aglietti decided to follow Fujita’s lead. Tapeworms have an intermediate host and a definitive one. In the former, they form a cyst; in the latter, they live as an intestinal worm. In 2005, Aglietti traveled to Kenya, toured cattle slaughterhouses searching for tapeworm cysts, found two, and swallowed them. Soon thereafter, Aglietti’s psoriasis plaques softened. A few months later, they’d almost entirely disappeared. But once a tapeworm matures, it begins releasing rather large, semi-self-propelled egg-filled sacks called proglottids. They slide out one’s rear and down one’s leg in search of new intermediate hosts.

“It’s just a very unclean feeling psychologically,” says Aglietti. “I just couldn’t deal with it.” He terminated the experiment with antiworm drugs. After passing a three-foot-long tapeworm, he set off in search of another, less psychologically disturbing parasite. This time, he settled on hookworm. Now he sells hookworms to others in Tijuana.

No doctor or scientist I’ve yet met would recommend traveling to Tijuana to acquire hookworm. Not only is this approach completely outside the realm of what’s proven to work scientifically, but those like Aglietti who offer the service—at least two operations exist as of this writing—also do so outside the scientific and medical establishment. No standards of quality or care exist save those that are self-imposed. And there’s just as little accountability if anything goes wrong.

The cons of what I’m about to do are therefore significant.

On the other hand, infecting oneself with hookworm has become an underground phenomenon of sorts, an unconventional treatment for often desperately ill people. I want to see what these individuals go through, how the process works.

And that brings me to the pros: I’ve heard fantastic tales of remission from people who’ve come this way. Some I can confirm. Many more I cannot. There’s nothing like seeing with your own eyes to settle questions like these. The potential benefits are also considerable—no worrying about peanuts, no wheezing, no more hay fever, no red, swollen eyes when cats jump in my lap. Sprouting a full head of hair would be icing on the cake. Most important, success might point the way toward the holy grail of prevention—not for me, but for my children.

At Aglietti’s clinic, I meet Dr. Jorge Llamas. He has a paunch, jowls, and a robust head ringed with trimmed white hair. Others who’ve passed this way have expressed great affection for him, and I can see why. He projects an easygoing, friendly manner that’s reassuring and soothing.

“We’re divorced from nature,” he tells me. “And it’s hurting us.” He rails against the modern obsession with cleanliness. Everyone is mindlessly following the United States’ lead, he says. And everyone is getting U.S. diseases. “We need to stop and think.”

I ask to see Aglietti’s blood work. Soon we’re shuffling through a year or two’s worth of tests. I confirm that Aglietti is clear of the major viruses—HIV, cytomegalovirus, hepatitis—as well as Strongyloides stercoralis, a nasty worm that, uniquely among soil-transmitted helminths, can reproduce in the host. I’m as satisfied as I’m going to be.

“Are you nervous?” asks Llamas.

“Do I look nervous?”

He shrugs. “A little.”

We move to a room at the back of the building. Aglietti has donned a light blue doctor’s overcoat with Worm Therapy embroidered in script over his right pectoral. He’s smiling and seems excited. With a pipette, Llamas removes what I’m assuming is larva-laden water from a beaker and squirts it onto an absorbent bandage.

The bandage goes on. Within a minute, I feel a tickling, itching, nearly burning sensation—rather like a mild case of stinging nettles. That’s the microscopic larvae burrowing through my skin.

Each larva will find its way into a capillary and hitch a ride on my venous blood flow, like rafters on a river. They’ll pass through the thunderous pump of my heart, which causes me no small degree of anxiety. And once they’ve arrived at the capillaries of my lungs, they’ll burrow out of the circulatory system into the bunch-of-grapes-like sacs called alveoli. They’ll then follow the coordinated sweeping motion of millions of hairlike cilia up and outward—the so-called mucociliary escalator—over the pharynx, where windpipe and food pipe branch, and plunge down into the esophagus.

They’ll miraculously survive the hydrochloric acid bath of my stomach and finally—after an odyssey through my body lasting several weeks—arrive at my small intestine, the final destination. They’ll latch on to my intestinal wall. They’ll mate. Large individuals will reach a centimeter in length. The females will lay perhaps 10,000 microscopic eggs daily, all the while grazing on intestinal tissue to the tune of 0.04 milliliter of blood per day. They can live for five years, maybe longer. The eggs, which require a week or two in tropical conditions to become infective larvae, will pass out with my stool—which, in New York City, means they end up in a wastewater treatment plant.

I might get a mild cough in a week or so, Aglietti explains. Flulike symptoms are common. Then “epigastric pain” once the worms attach. If I start coughing, I shouldn’t spit out
the discharge.

“Swallow it,” he says. “That’s your medicine.”

By now I have a headache. I’m filled with feelings of disgust, hope, and wonder—disgust with myself for agreeing (with myself) to this experiment; hope that the experiment may do some good; and wonder at the parasite’s biology, its ability to pierce skin, navigate circulatory systems, and, in the coming weeks, arrive at my small intestine. Underlying these sentiments is a recently acquired, quasi-religious faith in evolution—confidence that the organism knows what it’s doing and won’t kill me in the process. For an obligate parasite, a dead host is, after all, a useless host. For better or worse, we’re now in this together.

Excerpted from An Epidemic of Absence: A New Way of Understanding Allergies and Autoimmune Diseases, by Moises Velasquez-Manoff. Scribner, 2012. Reprinted with permission.

Don’t Try This at Home

In his book, An Epidemic of Absence, out in paperback this fall, Moises Velasquez-Manoff described infecting himself with hookworm to treat conditions like allergies and alopecia. Three years later, he says it’s too soon to call parasites a miracle cure.

In your book, you describe seeing some improvements in your health after self-infecting with hookworm—including temporary relief from allergies, and even a very fine regrowth of hair. But you also experienced some pretty uncomfortable side effects, like headaches and diarrhea. So was the experiment a success?

The original symptoms I was seeking to treat never went away. I had a brief period where my hay fever was completely gone—it was miraculous—and my eczema went away for a while. So, early on, there were very strong benefits. But those sort of faded with time, and then after a year and a half I started having asthma that became worse and worse and worse and worse. I was ignoring it, because I was busy finishing my manuscript, and because it didn’t come on right away, I didn’t attribute it to the worm infection
until later.

Eventually I dewormed, but the asthma was still there, so I was doubly screwed. I still don’t really know why my asthma got worse. The moral of the story is that not knowing why things are happening, including a worsening of symptoms, is a risk one runs in uncontrolled, homegrown self-experimentation.

How are you applying what you learned from this experience to your own family’s life?

For my daughter, the things that I felt comfortable with are clearly not exposing her to parasites, but a just having a good diet—eating lots of complex carbohydrates [which can be fermented by the bacteria already living in her gut]. If possible, I try to get her to eat fermented food. Unfortunately, the studies on fermented foods are just woefully not enough. Everybody assumes they’re protective, and there’s good reason to believe that they are, but the science is just not there yet.

One major thing I watch out for is antibiotics usage. If she needs antibiotics, she’s going to take them, but there is a gray area. For example, children get ear infections, otitis media. You can treat it with antibiotics, but it usually clears up on its own. When you treat it with antibiotics, you’re just napalming the gut microbiome, and you don’t necessarily need it.

Finally, I send her to day care. People might avoid day care because they think it’s dirty. There’s a lot of colds going around. But the evidence actually suggests some of that is good for you—day care has been shown to be protective against allergic disease and type 1 diabetes. Plus she seems to enjoy it.

After everything you learned through your research, as well as your own personal experience with hookworm, has your attitude toward parasites changed?

My attitude is the same: that actual science needs to be done. If I was one of 1,000 people given a parasite in a placebo-controlled trial, we would know what happened and why it didn’t help me. I mean, there’s a reason we do real science, and that’s because you just don’t know if things work unless you test in a rigorous way.

The science is snowballing in a sense, meaning that more and more people are looking into it. The tools for studying the microbiome are continually improving, and the hypotheses are going to continue to be evolving.

And Coronado Biosciences is currently testing pig whipworm on a number of disorders. What I did was hookworms—pig whipworm is a parasite that’s less invasive.

So we’ll actually have real data soon on whether that parasite helps, from placebo-controlled, double-blind studies. —Ilima Loomis