Infectious mononucleosis is also called ‘glandular fever’. It typically affects young adults aged 15 to 25 years. This disease is caused by human herpesvirus type 4, more often known as Epstein–Barr virus (EBV). This virus is passed from person to person by saliva, such as sharing a glass or kissing. Thus it is often called the kissing disease.
The incubation period from contact until symptoms is 1 to 2 months. Epstein–Barr virus is widespread in all human populations and is most often acquired asymptomatically in infancy. However, in well-off societies, primary infection can be delayed until the second or third decade, when 25–50 percent of those involved may develop symptoms. Hence infectious mononucleosis is typically a disease affecting adolescents or young adults in the Western world. Almost all patients recover completely within a few weeks. Still, rare cases with persistent, even fatal, symptoms do occur and involve those with a pre‐existing immune defect or unique individuals where the virus infection spreads into atypical cell types. There is no apparent association between this virus and the so‐called chronic fatigue syndrome.
