A common microbe found in sewage, marine sediment, soil, and the GI tracts of pets and farm animals may play a defining role in multiple sclerosis, according to a new study. The findings, published in The Journal of Clinical Investigation, suggest that a toxin produced by certain C. perfringens bacteria may be the long sought-after trigger that degrades the blood-brain barrier and kicks off the relentless inflammation and brain cell degradation characteristic of MS. “If this is the environmental trigger for MS, we can now start talking about a vaccine, monoclonal antibodies, or some other therapy,” says Rashid Rumah, co-author...