My posts of studies usually gets flamed, but here goes anyway:
“The prevalence of IBD is much less in regions of the world which have heavy worm infection. In fact, I got interested in the question of how worms can be beneficial when I was contacted by an individual who had deliberately infected himself with worms to treat his symptoms of IBD and was able to put his disease into remission.”
www.painnewsnetwork.org/stories/2016/4/20/does-washing-your-hands-lead-to-ibd