A steady rise in autoimmune diseases such as multiple sclerosis (MS) has been noted in recent decades, and environmental factors could be the cause of this increase. One theory, similar to the “hygiene hypothesis” in which an excessively germ-free environment may contribute to an increase in allergies, holds that a decline in infectious diseases may play a role in increasing autoimmune disease incidence. The first study examining the relationship between parasite infections and MS in humans suggests that such infections may affect the immune response in a way that alters the course of MS. The study was published in the January 2007 issue of Annals of Neurology (http://www.interscience.wiley.com/journal/ana), the official journal of the American Neurological Association.
