High Quality Content by WIKIPEDIA articles! Infectious mononucleosis (IM; also known as EBV infectious mononucleosis or glandular fever or Pfeiffer`s disease or Filatov`s disease and sometimes colloquially as the kissing disease from its oral transmission or simply as mono in North America and as glandular fever in other English-speaking countries) is an infectious, widespread viral disease caused by the Epstein–Barr virus (EBV), one type of herpes virus, to which more than 90% of adults have been exposed. Occasionally, the symptoms can recur at a later period. Most people are exposed to the virus as children, when the disease produces no noticeable symptoms or only flu-like symptoms. In developing countries, people are exposed to the virus in early childhood more often than in developed countries. As a result, the disease in its observable form is more common in developed countries. It is most common among adolescents and young adults.