Infectious mononucleosis

Infectious mononucleosis is a common viral infectious disease, also termed glandular fever, that belongs to the spectrum of Epstein-Barr virus-associated lymphoproliferative diseases. The condition is most frequently caused by Epstein-Barr virus (EBV), also known as human herpesvirus 4, though a minority of cases may arise from other viral agents or the protozoon Toxoplasma gondii. The disease represents a systemic infection characterized by lymphoid proliferation and atypical lymphocyte responses.

The clinical presentation varies substantially with age. In children before puberty, infection typically produces only mild flu-like symptoms or may be entirely asymptomatic, often manifesting as mild pharyngitis resembling common throat infections. In adolescents and young adults, the disease presents with a characteristic triad of fever, sore throat, and cervical lymphadenopathy, accompanied by prominent fatigue, headaches, and occasionally abdominal pain with nausea or vomiting. Most individuals recover within two to four weeks, though fatigue and malaise may persist for months in an estimated 28% of cases. Physical examination commonly reveals splenic enlargement during the second and third weeks, with hepatic enlargement also occurring; jaundice develops only occasionally. While the condition generally resolves spontaneously in healthy individuals, rare complications include splenic rupture in less than one percent of cases, and in rare instances the disease may progress to chronic infection or systemic EBV-positive T-cell lymphoma. Older adults who develop mono less frequently exhibit the characteristic triad and instead present with prolonged fever, fatigue, and body aches, with higher likelihood of hepatic involvement and jaundice, and increased risk of serious illness.

Infectious mononucleosis is a widespread viral infection with near-universal lifetime exposure to EBV in most populations. Primary infection typically occurs during childhood, when the disease produces minimal or no symptoms, while symptomatic disease predominantly manifests in adolescents and young adults. The condition is primarily diagnosed based on clinical presentation and confirmed through serological testing for specific antibodies, with characteristic laboratory findings including increased blood lymphocytes of which more than ten percent are reactive. The monospot test is not recommended for general use due to documented accuracy limitations. Source-backed detail regarding geographic distribution patterns, outbreak contexts, or precise surveillance burden is not yet available from the provided sources.

The primary mode of transmission for infectious mononucleosis is through direct contact with infected saliva, which has earned the condition its colloquial designation as the 'kissing disease.' The pathogen may also spread through shared objects contaminated with saliva, such as drinking glasses or toothbrushes, as well as via respiratory droplets from coughing or sneezing. Less commonly, transmission can occur through semen or blood exposure. Importantly, infected individuals can transmit the virus during the prodromal period, beginning several weeks before the onset of clinical symptoms.

Adolescents and young adults represent the population most commonly exhibiting symptomatic infectious mononucleosis with the characteristic clinical triad. Individuals over 40 years of age who acquire the infection face elevated risk of developing more serious illness and atypical presentations without the hallmark sore throat and lymphadenopathy. People who are otherwise healthy generally experience uncomplicated recovery, while those with underlying immunocompromising conditions may be at increased risk for atypical or severe disease courses, including potential progression to chronic infection or lymphoproliferative complications.

No vaccine currently exists for Epstein-Barr virus, though research into vaccine development remains ongoing. Prevention therefore relies on avoiding exposure to saliva from infected individuals, particularly during the weeks preceding symptom onset when transmission risk is elevated. Public health measures include avoiding sharing of drinking vessels, eating utensils, and personal hygiene items, as well as practicing respiratory etiquette to reduce droplet transmission risk.

Infectious mononucleosis is primarily diagnosed through clinical assessment of characteristic symptoms, supported by serological confirmation for specific antibodies rather than reliance on the monospot test due to its known accuracy limitations. Surveillance systems should account for the age-dependent presentation patterns, recognizing that children frequently experience asymptomatic or mild disease that may not come to medical attention, while cases in adolescents and young adults more commonly present with the full symptomatic syndrome. The potential for prolonged fatigue lasting beyond the acute phase should be considered when interpreting recovery timelines. Given the self-limiting nature in most healthy individuals and the absence of routine reporting requirements in many jurisdictions, captured case data may underrepresent true disease burden.

1. 1 Wikidata. infectious mononucleosis.
2. 2 Wikipedia. Infectious mononucleosis - Wikipedia.

ICD-10

B27

ICD-11

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