While three other studies have linked the Epstein-Barr virus (EBV) - which often causes mononucleosis - to multiple sclerosis, the new findings provide stronger evidence of a connection, said the report released on Monday.
The study, which was conducted by the Kaiser Permanente Division of Research in Oakland, California, involved individuals with multiple sclerosis who had given blood samples earlier in life when they were about 32 years of age.
The samples, which had been stored at cold temperatures, were compared to those of others in the same health plan that did not have the disease.
The researchers found that the levels of anti-EBV antibodies in the blood of the MS patients collected 15 years earlier were significantly higher than the levels in those who did not go on to develop the disease.
Antibodies are proteins produced by the body to fight infections.
The study said that perhaps 96% of Americans have been exposed to the virus by the time they reach age 40.
Hereditary and environmental factors are believed to play a role in MS, a chronic degenerative disease in which the body attacks its own central nervous system and that can cause paralysis.
Hope for treatment
"Collectively, the results of this and the previous studies provide compelling evidence that infection with (the virus) is a risk factor in the development of MS"
Alberto Ascherio, Associate Professor at Harvard School of Public Health
"Collectively, the results of this and the previous studies provide compelling evidence that infection with (the virus) is a risk factor in the development of MS," said Alberto Ascherio, a senior author of the study and associate professor of nutrition and epidemiology at Harvard School of Public Health.
The report was published in the Archives of Neurology.
"Discovering strong risk factors is ... an important initial step in finding ways to diagnose, treat, and prevent MS," Ascherio said.
"A focused multi-disciplinary effort is now needed to complete the puzzle and thus open the door to new therapeutic approaches."