USMLE

Epstein-Barr Virus (HHV4)

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Viruses - DNA Viruses
  1. Herpesvirus Overview
  2. Herpes Simplex Virus 1 (HSV1)
  3. Herpes Simplex Virus 2 (HSV2)
  4. Varicella-Zoster Virus (HHV3)
  5. Epstein-Barr Virus (HHV4)
  6. Cytomegalovirus (HHV5)
  7. Human Herpesviruses 6 and 7 (HHV6 and HHV7)
  8. Human Herpesviruses 8 (HHV8)
  9. Poxvirus
  10. Hepadnavirus
  11. Adenovirus
  12. Papillomavirus (HPV)
  13. Polyomavirus
  14. Parvovirus

Key Points

  • Ebstein-Barr virus (EBV)
    • Characteristics
      • Member of Herpesvirus family
        • Also known as human herpesvirus 4 (HHV-4)
        • Enveloped DNA virus with double-stranded, linear DNA 
          • Herpesviruses are unique in that they get their envelope by budding from nuclear membrane of host cell
    • Transmission
      • Saliva (“Kissing disease”)
        • Common in teens, young adults
        • 90-95% of the world population is seropositive for EBV
    • Pathogenesis
      • Infects B cells through CD21
        • EBV envelope glycoprotein gp350/220 binds to CD21 to attach to B-cells
      • May establish lifelong latency in B cells (like other herpesviruses)
        • T cell mediated immunity controls the latent infection, and reactivation disease is not clinically important
    • Presentation
      • Mononucleosis
        • Fever, fatigue are non-specific symptoms
        • Pharyngitis
          • with tonsillar exudates (white, gray-green, or necrotic)
          • severe cases may lead to airway obstruction
        • Lymphadenopathy
          • Symmetric distribution
          • Usually involves posterior cervical nodes
        • Splenomegaly/Splenic rupture risk
          • Avoidance of contact sports is mandatory
        • Associated with
          • Burkitt Lymphoma
          • Primary CNS Lymphoma (in HIV)
          • Nasopharyngeal carcinomas (especially Asian adults)
          • Many other types of B-cell lymphoma
          • Oral hairy leukoplakia in HIV patients
            • white corrugated plaques that cannot scraped (contrast vs. Candida)
        • Morbilliform rash after administration of penicillins (e.g. ampicillin/amoxicillin)
    • Studies
      • Atypical lymphocytosis on peripheral blood smear
        • Not infected B cells but reactive cytotoxic T cells
      • + Heterophile test (Monospot)
        • Heterophile antibodies (“other-liking”) agglutinate RBCs from sheep or horses
        • Highly specific for EBV infection
    • Treatment
      • Supportive care; pharmacologic treatment is not mandatory
        • Acetaminophen and NSAIDs may be given for fever
      • Acyclovir and and related drugs (famciclovir/valacyclovir) are not effective
        • due to lack of needed viral thymidine kinase