In developed countries, we've mostly eliminated freeloaders like parasitic worms from our guts. But we also have the highest rates of inflammatory bowel disease, or IBD—when the immune system mistakenly attacks intestinal cells and friendly gut bacteria.

For years, docs suspected there might be a connection between IBD and our worm-free lifestyle. And a handful of studies have actually shown that infecting human patients with worms can reduce symptoms of the disease. But how?

To find out, researchers fed parasitic worm eggs to monkeys with chronic diarrhea and gut inflammation—similar to IBD. After infection, the monkeys' immune systems kicked into high gear, pumping out more mucus than usual to fight the worms. But that response also helped heal the monkeys' intestines—restoring healthy, diverse populations of gut bacteria and decreasing the diarrhea. Those results appear in the journal PLoS Pathogens. [Mara Jana Broadhurst et al., Therapeutic Helminth Infection of Macaques with Idiopathic Chronic Diarrhea Alters the Inflammatory Signature and Mucosal Microbiota of the Colon]

The researchers already have FDA approval to study the worms in human subjects. Interested patients can go to clinicaltrials.gov to sign up—and hopefully worm their way out of intestinal distress.

—Christopher Intagliata

[The above text is a transcript of this podcast.]