A virus that infects more than 90% of adults and causes the “kissing disease” has been linked with the onset of multiple sclerosis in a new study.

Researchers at Harvard University have added further evidence that the same virus which causes the illness mononucleosis, a k a “mono,” and commonly passed through saliva — hence “kissing disease” — may also encourage the development of multiple sclerosis, an inflammatory demyelinating disease of the central nervous system.

The Epstein-Barr virus is a member of the herpes family, and one of the most common human viruses in the world. Some EBV infections may prompt fever, rash, sore throat, body aches and swollen glands — the conditions of mononucleosis.