Epidemiology and Prevention of Viral Hepatitis A to E

Overview of Hepatitis Viruses

• Types: Hepatitis A, B, C, D, E
• Transmission modes:
  • Fecal-oral (Hepatitis A, E)
  • Blood/body fluids (Hepatitis B, C, D)
• Chronic infection possibility:
  • Yes: B, C, D
  • No: A, E

Historical Perspective

• Source of virus varies: feces, blood, blood-derived body fluids
• Route of transmission: fecal-oral, percutaneous, permucosal
• Prevention includes immunization, screening, and behavior modification

Hepatitis A Virus (HAV)

Characteristics

• Incubation period: Average 21 days (14-50 days range)
• Symptoms: Jaundice varies by age
  • <6 yrs: <10%
  • 6-14 yrs: 40-50%

  • 14 yrs: 70-80%

• Complications: Fulminant, cholestatic, and relapsing hepatitis
• Chronic Sequelae: None

Transmission

• Main source: Stool
• Methods:
  • Personal contact (household, child care, sexual)
  • Contaminated food/water (food handlers, shellfish)
  • Rare blood exposure (drug use, transfusion)

Diagnosis and Prevention

• Diagnosis through detection of HAV-IgM in serum
• Prevention:
  • Sanitation improvement
  • Vaccination for travelers, high-risk groups
  • Post-exposure prophylaxis with vaccine or IG

Hepatitis B Virus (HBV)

Characteristics

• DNA virus, part of Hepadnaviridae family
• Contains 4 genes: S, C, X, P
• Incubation period: Average 60-90 days (45-180 days range)
• Chronic infection varies by age at exposure

Transmission

• High-risk fluids: blood, semen, saliva
• Modes: Sexual, parenteral, perinatal

Diagnosis and Treatment

• Serological tests: HBsAg, HBsAb, Anti-HBc, HBeAg
• Treatment for chronic HBV: Interferon, nucleos(t)ide analogs
• Prevention through vaccination and immunoglobulin

Hepatitis D (Delta) Virus (HDV)

Characteristics

• Coinfection and superinfection scenarios
• High risk of chronic infection with superinfection

Transmission and Prevention

• Percutaneous and permucosal exposure
• Prevention involves education on risk reduction

Treatment

• Interferon alpha for 48 to 72 weeks
• Nucleos(t)ide analogs ineffective

Hepatitis C Virus (HCV)

Characteristics

• RNA virus, Flaviviridae family
• Incubation period: 6-7 weeks (2-26 weeks range)
• High rate of chronic hepatitis and persistence

Transmission

• Modes: Percutaneous, sexual, perinatal
• Risk factors include drug use, tattoos, and transfusions

Diagnosis and Treatment

• HCV antibody and RNA detection
• Treatment: Direct-acting antivirals (DAAs)
• Prevention through screening and behavior modification

Hepatitis E Virus (HEV)

Characteristics

• RNA virus, Hepeviridae family
• Incubation period: 40 days (15-60 days range)
• High fatality in pregnant women

Transmission and Prevention

• Self-limited acute infection
• Avoid unsafe water and food in endemic areas
• ?Vaccine?