Epstein-Barr Virus (EBV) and Infectious Mononucleosis

Overview of Epstein-Barr Virus

• Typically causes asymptomatic infection or acute tonsillitis
• Part of a larger infection called Infectious Mononucleosis (IM) or Glandular Fever
• Common in adolescents and young adults
• Transmitted orally via saliva ("kissing disease")
• Nearly everyone gets infected at some point
• Most cases are asymptomatic

Pathophysiology

• Begins with saliva transmission
• Targets tonsils (lymphoid tissue: T cells and B cells)
• Targets B cells and epithelial cells in tonsils (primary infection, usually asymptomatic)
• Incubation period: 2 to 6 weeks
• Virus replicates in B cells and sheds in pharyngeal secretions (saliva)
• Immune response:
  • B cells capture and process EBV antigens
  • Immune response in tonsils and other lymphoid tissues (spleen, liver)
  • CD8 T-cells (cytotoxic T-cells) suppress the primary infection
  • Activation of CD4 T-cells and B-cells (plasma cells produce EBV-specific antibodies)
• Antibodies produced:
  • Viral Capsid Antigen (VCA) with IgM (early marker)
  • VCA with IgG (later marker)
  • EBV Nuclear Antigen (EBNA) IgG (marker of infection resolution)
• Abnormal B-cells produce heterophile antibodies (used in diagnosis)

Transition to Infectious Mononucleosis

• Strong immune response can cause symptoms (IM)
• Spread from oral cavity to bloodstream to spleen, liver, lymph nodes
• Clinical features:
  • Tonsillitis, pharyngitis, fever, malaise, lymphadenopathy
  • Hepatosplenomegaly, leukoplakia (whitish patches in the mouth)
  • Enlarged tonsils with exudate, potential airway compression
• Diagnosis:
  • Clinical suspicion (fever, pharyngitis, cervical lymphadenopathy)
  • Blood tests: lymphocytosis, heterophile antibody test (Monospot test)
  • EBV-specific antibodies (VCA IgM, VCA IgG, EBNA IgG)
  • PCR for EBV DNA (for difficult cases)
  • Throat swab to rule out bacterial infection (e.g., Strep throat)

Immune Response Details

• Graph: Time vs. Antibody concentration
• EBV enters oropharynx, infects tonsils, then enters bloodstream
• Antibody timeline:
  • Early: VCA IgM
  • Later: VCA IgG, EBNA IgG
• Symptoms during immune response: fever, malaise (due to cytokines)
• Heterophile antibodies help in diagnosis

Treatment and Management

• Conservative management for symptomatic cases (IM):
  • Pain and temperature management (e.g., Ibuprofen, Paracetamol)
  • Rest, fluids, nutrition
  • Rarely need more than supportive care
  • Severe cases: hospital admission, possible ENT involvement
  • Treatments: steroids (reduce swelling), potential airway management (nasopharyngeal airway, intubation, tonsillectomy)
• Complications:
  • Splenic rupture, leukoplakia, Burkitt's lymphoma, lymphoproliferative disease
  • Antibiotics (e.g., Ampicillin) may cause rash in EBV tonsillitis cases (not recommended)

Key Points

• EBV usually asymptomatic but can cause IM if symptoms appear
• IM caused primarily by EBV, but other viruses can also cause it

Summary

• EBV infection often asymptomatic
• IM symptoms include sore throat, fever, lymphadenopathy, fatigue
• Diagnosis: clinical evaluation, blood tests for antibodies, PCR, throat swabs
• Treatment: mainly supportive care, hospital management for severe cases

Additional Notes

• EBV is part of the herpes virus family
• Known as the "kissing disease" due to transmission mode
• Antibody responses help trace infection stages and resolution