A New Prescription: Parasite Eggs

Whipworms are two-inch-long parasites that sicken pigs by burrowing into their guts. Scientists, however, are beginning to appreciate them for their curative power in humans. Large-scale trials underway in Europe are testing whipworm eggs as a treatment for autoimmune diseases such as Crohn's, a digestive ailment, and multiple sclerosis. About 23.5 million Americans have some type of autoimmune disorder. "This is probably the biggest market in the entire history of medicine," says Detlev Goj, founder of Ovamed, a German biotech. He believes whipworm eggs may prove effective against as many as 60 diseases.

Goj, who in 2002 got European regulators to approve the use of maggots to clean wounds, became interested in whipworms after coming across a 2005 study in which 21 out of 29 patients with Crohn's disease went into complete remission after being dosed with the parasite's eggs. The data seemed to support the "hygiene hypothesis," which holds that people have become too clean for their own good. The thinking is that parasites may act on the immune system by boosting the T-cells that help identify and kill infectious agents. When those cells don't work properly, substances and tissues normally present in the body can be mistakenly targeted, causing a range of disorders. "Now that we've eliminated parasites in many Western countries," says Goj, "the immune system doesn't get the required challenge anymore."