Scientists May Have Found the Main Cause of Multiple Sclerosis

A groundbreaking study from Harvard University has identified Epstein-Barr virus (EBV) as the likely primary cause of multiple sclerosis (MS), an autoimmune disease affecting the brain and nervous system. Researchers led by Dr. Alberto Ascherio examined health records from over 10 million U.S. military personnel, finding that 955 individuals diagnosed with MS had all been infected with EBV before symptoms appeared. The virus, part of the herpes family, infects 95% of adults globally and often remains dormant after initial exposure, typically in childhood or adolescence. MS occurs when the immune system mistakenly attacks myelin, the protective covering around nerve fibers in the brain and spinal cord. Damage to myelin disrupts nerve signals, leading to symptoms like muscle weakness, vision problems, fatigue, and coordination issues. While MS has no cure, the study suggests EBV may trigger the disease in genetically susceptible individuals, often after a delay of a decade or more. The military population provided a unique dataset, as service members undergo regular blood tests, allowing researchers to track EBV infections over time. The findings challenge previous theories about MS and could lead to new prevention strategies, such as EBV-targeted vaccines. The study also highlights the need for further research to confirm the virus’s role and explore potential interventions. EBV infections are common but usually cause few symptoms, except in cases of infectious mononucleosis ("mono"), which includes fatigue, fever, and swollen lymph nodes. The long latency between infection and MS diagnosis has made it difficult to establish a direct link, but the Harvard study’s large sample size strengthens the evidence. If confirmed, the discovery could reshape understanding and treatment approaches for MS, a condition affecting 2.8 million people worldwide.