Can Parasitic Worms Treat Autism?

A growing body of evidence suggests that in some patients, increased inflammation contributes to autistic behaviors. Now, a Phase I clinical trial is under way to measure the effects of infecting autistic patients with a non-pathogenic parasitic worm. Scientists at Montefiore Medical Center at the Albert Einstein College of Medicine in New York and biotech company Coronado Biosciences will test the hypothesis that treating these patients with Trichuris suis, a non-pathogenic parasitic pig whipworm, will dampen their immune responses and ameliorate repetitive and irritable behaviors.

“The trial is a novel approach [to autism treatment] with a naturally occurring drug delivery system”—a parasitic worm, said Eric Hollander, a Montefiore psychiatrist and head scientist on the trial.

Autoimmune and allergic diseases are more prevalent in more developed countries where citizens are accustomed to better water quality and less contact with farm animals. Some researchers chalk this phenomenon up to the so-called hygiene hypothesis, which posits that the microbes and parasites that humans co-evolved with act to help keep our immune responses in check. The theory was spurred initially by observations in humans—that after anti-parasitic therapy, people scored higher on allergy skin prick tests, or that autoimmunity and allergies were more prevalent in more-developed West Germany than East Germany—and supported by laboratory studies on mouse models of such diseases, said Marie-Helen Jouvin, a pathologist at Beth Israel Deaconess Medical Center and Harvard University, who is not involved in the clinical trial. Parasites, such as the whipworm used in the autism trial, are thought to both dampen inflammation and stimulate immune regulatory pathways in their hosts.