Epstein-Barr Virus (Infectious Mononucleosis)
Epstein-Barr virus (EBV) is a double-stranded DNA virus implicated as a causative agent for infectious mononucleosis by an infected laboratory worker in 1968.
- Worldwide distribution
- Humans are the only known reservoir.
- Transmission occurs through saliva and, occasionally, via blood transfusions and solid organ transplant (SOT).
- Incubation period is 4 to 7 weeks.
- Antibodies to EBV are present in up to 90% of adult populations.
- Areas with a high population density or low socioeconomic status usually become primarily infected within the first 3 years of life.
In developed countries, acquisition of EBV is biphasic.
- Initial peak in incidence occurs before the age of 5 years.
- Second peak occurs during adolescence, coinciding with an increased frequency of intimate oral contacts.
>90% of adults have demonstrable EBV titers.
- No vaccine is clinically available.
- Standard precautions should be used in the hospitalized patient.
- Restriction of intimate contact with immunosuppressed individuals may be advisable.
- Patients with recent EBV infection, either proven or suspected, should not donate blood or solid organs.
- Enters host via saliva and replicates initially in the oropharyngeal epithelium
- Selective infection of B lymphocytes occurs.
- The clinical syndrome of infectious mononucleosis results from proliferation of cells in the tonsils, lymph nodes, and spleen.
- Nonspecific humoral immune responses include the formation of heterophile antibodies and autoantibodies.
- Specific antibodies to EBV antigens are produced.
- Despite humoral responses, cellular immunity is responsible for controlling EBV infection.
- Latent, lifelong infection of B lymphocytes occurs.
- Latent virus may be reactivated during periods of immunosuppression or cellular stress.
Commonly Associated Conditions
- Subclinical infection
- Most EBV infections in children, and even in adolescents, are clinically inapparent.
- Mild, nonspecific symptoms may include coryza, diarrhea, and/or fever.
- Immunologic seroconversion does occur.
- Infectious mononucleosis (“glandular fever”): most commonly observed with late primary acquisition of EBV. The classically defined illness is characterized by the following:
- Tonsillopharyngitis (often exudative)
- Usually associated with increased atypical lymphocytes in the peripheral blood
- Rare illnesses of the nervous system have been reported, including the following:
- Guillain-Barré syndrome
- Bell palsy
- Aseptic meningitis
- Peripheral and/or optic neuritis
- Hematologic complications have been reported in association with EBV:
- Aplastic anemia
- Hemolytic anemia
- Hemophagocytic syndrome
- Other illnesses associated with EBV in case reports include the following:
- Hemolytic uremic syndrome
- Mesenteric adenitis
- Genital ulcerative disease
- Lymphoproliferative disorders
- Burkitt lymphoma
- Nasopharyngeal carcinoma
- Lymphoma and non-Hodgkin lymphoma (in immunocompromised children)
- Lymphomatoid granulomatosis
- Posttransplant lymphoproliferative disorders (PTLDs)
- X-linked lymphoproliferative disease (Duncan disease)
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