It has recently been argued that the hygeine hypothesis may explain part of the pattern of MS incidence around the world. MS is a disease of affluent countries where sanitation has effectively eliminated many of the organisms that previously inhabited the human gastrointestinal tract. Previous data suggested that MS is less active in individuals with some of these infestations, in particular, worm infestations of the bowel. The researchers in this study from Wisconsin conducted a small pilot study of five people with MS to whom they gave an oral suspension of porcine whipworm, a non-toxic parasite that doesn't infect humans and is not contagious, but does provoke an immune reaction. They showed that this administration provoked a strongly anti-inflammatory reaction, reducing the number of new MS lesions from 6.8 on average before administration to two lesions after administration, with a return to previous disease activity once the administration was stopped. This is very exciting news! It paves the way for large scale trials of the whipworm administration. Who would have thought that one of the keys to controlling this illness might be in the very bugs we have been trying to get rid of?