Epstein-Barr Virus Found to Trigger Multiple Sclerosis

It has been difficult to prove a connection between the human herpesviruses and multiplesclerosis. 95 percent of adults carry the Epstein-Barr virus, which is the primary cause of mononucleosis. It is relatively rare that a devastating demyelinating disease of the central nervous system is found. It affects more than 2 million people. People who contract infectious mononucleosis have a slightly increased risk of developing the disease.

A research study would have to show that people wouldn't develop the disease if they hadn't been exposed to the virus. A randomized trial to test such a hypothesis would be unethical.