DefinitionMononucleosis is a viral infection causing fever, sore throat, and swollen lymph glands, especially in the neck.See also: Infectious mononucleosis (acute CMV infection)Alternative NamesMono; Kissing diseaseCauses, incidence, and risk factorsMononucleosis, or mono, is often spread by saliva and close contact. It is known as "the kissing disease," and occurs most often in those age 15 to 17. However, the infection may develop at any age.Mono is usually linked to the Epstein-Barr virus (EBV), but can also be caused by other organisms such as cytomegalovirus (CMV).SymptomsMono may begin slowly with fatigue, a general ill feeling, headache, and sore throat. The sore throat slowly gets worse. Your tonsils become swollen and develop a whitish-yellow covering. The lymph nodes in the neck