Infectious mononucleosis

Infectious mononucleosis (or glandular fever) is usually a self-limiting disease caused generally by the Epstein-Barr virus (EBV), a member of the herpes virus family. The virus replicates mainly in B – lymphocytes and in some instances in the epithelial cells of the pharynx and parotid duct (1).

The virus is seen throughout the world and most people are infected by EBV at some point in their lives (2)

• in developed countries it is commonly seen between the ages of 15 and 25 years, and presents as infectious mononucleosis
• infection in children under 3 years is common in developing countries and is usually subclinical.
• infants becomes susceptible to EBV when maternal antibody protection present at birth disappears (2).

The virus is excreted for some months in nasopharyngeal secretions (primarily by saliva) which are responsible for person-to-person transmission. (1)

• many asymptomatic carriers may spread the virus intermittently through out their life (2)
• it is often called the kissing disease since kissing can spread the virus (3)
• it may also be spread by coughing, sneezing, or sharing a glass or food utensil
• chewing contaminated toys may cause infections in children (4)

The possibility of developing IM after acute EBV infection appears to increase with age

• in children - it is less than 10%
• adolescents and young adults – between 20% - 70% (5)

It is not as contagious as common cold. Although a self-limiting disease, the virus remains in the body for life (3).

A GP with 10,000 patients can expect around seven new cases of infectious mononucleosis per year (although this number will increase in practices with a high number of young people) (6). General practitioners therefore play an important role in the diagnosis of IM as they encounter the vast majority of patients with EBV-related disease (7)

Approximately 10% to 20% of susceptible people become infected with Epstein-Barr virus (EBV) each year, and IM develops in 30% to 50% of these people. (8)

References:

1. Mark H. Ebell. Epstein-Barr Virus Infectious Mononucleosis. Am Fam Physician 2004;70:1279-87,1289-90.
2. Center for Disease Control (CDC) 2006. National Center for Infectious Diseases - Epstein-Barr virus and Infectious Mononucleosis
3. Introduction. Infectious mononucleosis. Mayo Clinic-Mayo Foundation for Medical Education and Research.2008
4. Health Protection Agency (HPA) 2009. Factsheet on Glandular fever
5. Dowd JB, Palermo T, Brite J, et al. Seroprevalence of Epstein-Barr virus infection in U.S. children ages 6-19, 2003-2010. PLoS One. 2013 May 22;8(5):e64921.
6. Candy B et al. Recovery from infectious mononucleosis: a case for more than symptomatic therapy? A systematic review. Br J Gen Pract. 2002;52(483):844-51
7. Fugl A, Andersen CL. Epstein-Barr virus and its association with disease - a review of relevance to general practice. BMC Fam Pract. 2019 May 14;20(1):62.
8. Luzuriaga K, Sullivan JL. Infectious mononucleosis. N Engl J Med. 2010 May 27;362(21):1993-2000.