Therapy that squirms

“EAT worms” may be more than a childhood taunt hurled at enemies on the playground. It also may be good advice.

Some scientists believe that swallowing a concoction of certain parasites may relieve the often-debilitating symptoms of Crohn’s disease and ulcerative colitis, the two most common inflammatory bowel disorders.

Irritable bowel disorders affect an estimated 1 million to 2 million Americans. They most often strike teenagers and young adults, and symptoms -- ulcers, bleeding, severe abdominal pain or uncontrollable diarrhea -- can persist for life. Chronic sufferers are at a higher risk for colon cancer and can experience malnutrition, anemia and social isolation.

“They’re afraid to ride in cars or go to restaurants because they might soil themselves,” says Dr. Joel Weinstock, a gastroenterologist at the University of Iowa College of Medicine in Iowa City who helped devise the worm therapy.

Weinstock hit on the idea about a decade ago when he noticed that the incidence of inflammatory bowel disorders in industrialized nations had increased substantially over the last 50 years, coinciding with vast improvements in sanitation and personal hygiene.

Furthermore, researchers have noticed, Crohn’s disease and ulcerative colitis (disorders in which immune system cells attack gut tissue as if it were a foreign invader) are almost nonexistent in less developed countries where people are routinely exposed to intestinal parasites.

Weinstock and other scientists have come to believe that our penchant for cleanliness stamped out helpful parasites that dampen the immune system, making us more prone to developing Crohn’s and ulcerative colitis. After all, for thousands of years people walked around with a bellyful of worms -- hookworms, tapeworms, pinworms -- and the human immune system evolved to cope with their presence.

Without the worms, the immune system can become hyperactive, triggering the autoimmune reactions, experts say.

It’s also possible that the worms secrete chemicals that prevent the excessive immune response, Weinstock says. Scientists don’t know the exact mechanism of action, he adds, “but we do know that people who live in a wormy environment are less likely to have inflammatory bowel disease.”

Theoretically, putting the worms back into the gut should suppress this immune response. Early tests in 1998 were encouraging.

Six patients with chronic irritable bowel disorder who weren’t doing well on medications were given cocktails containing pig whipworm eggs. The researchers used pig whipworms because they were genetically similar to human whipworms but stay in the human body for only a few weeks (and can’t be transmitted to another person). Five patients went into remission and the sixth greatly improved.

Although researchers acknowledge that most people would shudder at the thought of ingesting parasites, they point to the desperation of people with the disorders. Current treatments, such as steroids, sulfa drugs and immune suppressants, can have unpleasant side effects and fail to help up to 30% of people with irritable bowel disorders.

“The drugs we have today are not perfect, and there is a group of patients who have lifelong problems trying to keep their symptoms under control,” says Dr. Stephan R. Targan, a gastroenterologist and immunologist at Cedars-Sinai Medical Center in Los Angeles.

Researchers have launched a larger study involving about 100 patients who have either Crohn’s disease or ulcerative colitis. Half got the worm egg solution and the others received a placebo mixture. Test results will be released later this month.

“We’ve had patients who’ve been taking this for four years now,” Weinstock says. “Obviously, they keep coming back because they feel it helps them.”

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Are we too clean for our own good?

Overall, better sanitation has made society much healthier, but our hygiene obsession has had some unintended consequences, say some experts. It may be the culprit behind the increased incidence of such autoimmune diseases as asthma, allergies, hay fever, diabetes, rheumatoid arthritis and multiple sclerosis.

Israeli scientists, for example, discovered that rats raised in germ-free environments developed more arthritis and diabetes than other rats.

And a Danish study released last month found that having siblings or pets or living on a farm reduced risks of allergic illnesses in babies because it increased their exposure to microbes.

“The hygiene hypothesis does make sense,” says Clive Shiff, a parasitologist at the Johns Hopkins Bloomberg School of Public Health in Baltimore. “Somehow, [exposure to microbes] stimulates the production of certain immune system cells that dampen the immune response.”