Multiple sclerosis (MS) is an inflammatory, demyelinating disease which affects the central nervous system (CNS). The etiology of MS is unknown, although the immune system appears to play a role. Many different infectious agents have been proposed as potential causes for MS, including Epstein-Barr virus, human herpesvirus 6, and coronaviruses. Recently Dr. Sriram at Vanderbilt University has found evidence for active Chlamydia pneumonia infection in the CNS of MS patients. These findings have been replicated in part by other laboratories.