Approximately 95% of adults worldwide are infected with Epstein-Barr virus (EBV), which is a member of the human herpes virus family.1
The infection is usually asymptomatic, but some may develop the clinical syndrome of infectious mononucleosis (IM) or glandular fever, which is usually a self-limiting illness.1 IM has an increased incidence between 15-24 years.2 IM is more likely to affect those who acquire primary EBV in their teenage years. In young adults, the rate of developing IM from primary EBV infection is estimated at 50%.1 A GP practice with a list size of 10,000 patients may expect to see 7 people with glandular fever each year.2
In developing countries and locations with lower socioeconomic status, most EBV infections occur in childhood. Infection is rare during the first year of life because of passive immunity received from maternal antibodies. 50% of children will have detectable Epstein-Barr virus antibodies by 5 years of age.1 In older adults, EBV infection often does not progress to IM. There does not appear to be any seasonal variation in the incidence of the syndrome.1
Non-EBV mononucleosis syndrome may also be caused by human herpes virus 6 (9%), CMV (5% to 7%), HSV-1 (6%) and rarely by malignancy or a drug reaction.1
How is it transmitted?