A very common virus may be the trigger for multiple sclerosis

Scientists have long linked the virus that causes mono to MS. Evidence is mounting that a garden-variety virus that sometimes causes mono in teens is the underlying cause of multiple sclerosis, a rare neurological disease in which the immune system attacks the brain and spinal cord, stripping away protective insulation around nerve cells, called myelin. It’s still unclear how exactly the virus—the Epstein-Barr virus (EBV)—may trigger MS and why MS develops in a tiny fraction of people. About 95 percent of adults have been infected with EBV, which often strikes in childhood. MS, meanwhile, often develops between the ages of 20 and 40 and is estimated to affect around one million people in the US. Yet, years of evidence have consistently pointed to links between the childhood virus and the chronic demyelinating disease later in life. With a study published in Science, the link is stronger than ever, and outside experts say the...