What Causes Multiple Sclerosis? Scientists Say It Might Be the Epstein-Barr Virus

Multiple sclerosis is a type of progressive disease that affects roughly 2.8 million people across the globe and unfortunately has no definitive cure as of yet. A study led by researchers from the Harvard T.H. Chan School of Public Health says that it may be due to an infection of the Epstein-Barr virus.

What is Multiple Sclerosis?

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According to the Mayo Clinic, Multiple Sclerosis is a disease of the spinal cord and brain that can cause multiple disabilities. With MS, the body's immune system attacks that natural protective sheath of myelin that covers and protects the nerve fibers and causes misfires and communication problems between the body and the brain. Eventually, MS causes permanent damage and deterioration to a person's nerves.

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Epstein-Barr Prime Suspect for Causing Multiple Sclerosis

Alberto Ascherio, the co-author of the study and a professor of epidemiology and nutrition at Harvard Chan School, explains that the hypothesis that the virus Epstein-Barr causes multiple sclerosis has not only been investigated by their group but also by other specialists over the past several years; however, this is the first study to provide completing evidence of causality. He adds that the recent findings are a major step towards progress because it suggests that most cases of multiple sclerosis could be prevented by EBV infection prevention, and targeting EBV may lead to the eventual cure of MS, reports EurekAlert.

MS's cause remains unknown, yet the prime suspect for many is EBV, a herpes virus known to cause infectious mononucleosis and establish the lifelong infection of its host. Establishing the causal relationship between multiple sclerosis and the Epstein-Barr virus has been difficult since EBV infects roughly 95% of adults. MS is a rare disease, and the onset of the disease's symptoms begins roughly ten years after the infection of EBV. To determine the causal relationship between MS and EBV, researchers studied roughly 10 million young adults currently on active duty in the US military, identifying 955 diagnosed with MS during their service period.

In the study published in the journal Science, titled "Longitudinal analysis reveals high prevalence of Epstein-Barr virus-associated with multiple sclerosis," researchers analyzed serum samples derived biennially by the US military. The first sample determined the EBV status of soldiers and the causal relationship between EBV infection and multiple sclerosis onset during the soldiers' period of active duty. In the study, the risks of multiple sclerosis increased in the sampled soldiers by 32-fold after getting infected with EBV but were uncharged after infection with other viruses. Serum levels of neurofilament light chain, a known biomarker of nerve degeneration that is typical in MS, increased after EBV infection. Known risk factors of MS cannot explain the findings of the cohort. This suggests that EBV is the leading cause of MS.

Ascherio explains that the delay in infection of EBV and onset symptoms and diagnosis of MS may be due to the disease's symptoms often being undetected in its earliest stages. He adds that currently, there are no ways to prevent or let alone treat EBV infection effectively; however, EBV vaccines that target the EBV could ultimately avoid or, more importantly, cure multiple sclerosis.