Infectious mononucleosis

Lore & Background

Infectious mononucleosis is primarily caused by the Epstein–Barr virus, a member of the herpesvirus family. The infection is spread mainly through saliva, though rarely through semen or blood. Most people are infected as children, when symptoms are few or absent; in young adults, the disease often presents with fever, sore throat, swollen lymph nodes, and fatigue. The incubation period is estimated at 30–50 days (4–6 weeks), with symptoms appearing around 4–6 weeks after infection in adolescents and young adults.

Reader's Guide

Infectious mononucleosis is significant as a common cause of illness in adolescents and young adults, responsible for about 8% of sore throats in those aged 16 to 20. Nearly 95% of adults have been infected with EBV, but only a minority develop symptomatic mono. The disease typically resolves without specific treatment, though fatigue may persist for months. Complications are rare but include splenic rupture in less than 1% of cases. There is no vaccine for EBV, though research continues. The monospot test is not recommended due to poor accuracy; diagnosis is based on symptoms and confirmed by antibody tests. The disease was first described in the 1920s and remains a notable cause of morbidity in young adults.

Did You Know?

• Infectious mononucleosis is colloquially known as 'the kissing disease'.
• About 25 out of 100,000 people develop infectious mono each year in the United States.
• Fatigue lasts more than one month in an estimated 28% of cases.
• The monospot test is a rapid screening test with moderate sensitivity and specificity, commonly used in clinical settings.