The upside of Linda Mansfield’s research is that it may lead to a new treatment for inflammatory bowel disease. The downside is that it would involve swallowing worm eggs. Mansfield is a professor of microbiology at Michigan State University who specialises in the study of parasites.

Inflammatory bowel disease, the most common forms of which are Crohn’s disease and ulcerative colitis, is a condition that is virtually unknown in the developing world. But it is becoming increasingly common in industrialised countries.

Researchers have put forward several explanations for that, among them diets high in fat and refined foods. But another possible cause, Mansfield said, is increasing levels of hygiene. Portions of the immune system actually require periodic infections in order to develop properly. Some exposure to dirt, bacteria and even worms can be beneficial.

“By living in an ultra-clean environment,” Mansfield said, “we’re removing some of the things that helped to educate our immune system.” Mansfield said it’s possible that the human immune system developed in a way that’s reliant, to some degree, on the presence of parasitic worms. She wasn’t the first to hit on that idea. A research team at the University of Iowa already has tried treating human patients with a whipworm egg and Gatorade cocktail. Their results were promising.

“There are probably individuals in the population who, back when worms were prevalent, were the healthiest because their immune systems could fight off all sorts of things,” he said. “When worms are removed, their immune systems become unbridled, and they move on to develop disease.” Mansfield came to the topic from an animal angle. More than a decade ago, she began studying whipworm infections in pigs, initially trying to develop a vaccine against the parasites.

But one of the things she noticed along the way was that whipworm infections produced a strong anti-inflammatory immune response. When given to patients with inflammatory bowel disease, the worms can help to counteract the inflammation and “actually reset the immune system to be in better balance,” Mansfield said. Further, pig whipworms are relatively safe. Most people will expel them in a matter of weeks and, if that doesn’t happen, they can be eliminated with anti-worm drugs. That’s promising, though a little unpleasant. — Agencies