Researchers are piecing together how a previous infection with the Epstein-Barr virus can catapult the development of MS. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The human body has myriad defenses to protect itself from disease and infection, but sometimes those biological bulwarks can become a threat themselves when they attack healthy cells and tissues, often by mistake. This autoimmune mixup can create debilitating chronic conditions like multiple sclerosis (MS), which affects nearly two million people worldwide. In MS, the immune system attacks a protective tissue called myelin, insulating the central nervous system. The resulting damage to nerves prevents the back-and-forth of messages across the body...