Parasite Turned Protector

These are whipworm (Trichuris trichiura) eggs taken from the gut of a patient who deliberately infected himself to treat an inflammatory bowel disease called ulcerative colitis. Whipworms are a type of helminth – parasitic worm-like organisms that reside in the intestines of infected mammals and avoid being turfed out by controlling their host’s immune response. They can cause diarrhoea and even anaemia in some people. But helminths may also protect their hosts from autoimmune diseases, which arise when the immune system mistakenly attacks healthy cells and tissues. In this case, whipworm infection forced the patient’s ulcerative colitis into remission, apparently by encouraging the proliferation of immune cells that churn out inflammation-reducing proteins. There are now several clinical trials underway to see if helminth therapy – purposefully infecting patients with helminths – could be a viable and safe way to treat various autoimmune diseases, including Crohn’s disease, multiple sclerosis, and type 1 diabetes.

Written by Daniel Cossins

Daniel Cossins

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As a freelance science writer, Dan's work has been published in award-winning magazines including BBC Focus, Wired UK, Cosmos, BBC Knowledge, BBC History and Men's Health.

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• Image by Natasha Girgis, Uma Mahesh Gundra and P'ng Loke
• New York University, USA
• Originally published under a Creative Commons Licence (BY 3.0)
• Research published in PLOS Pathogens, April 2013