Hepatitis E virus

Background

Microbiology

• Refers to viruses in the Hepeviridae family of RNA viruses
  • Genus Orthohepevirus, which infects terrestrial mammals and contains species A-D
    • HEV-A is the main human pathogen
      • Genotypes 1 and 2 only infect humans
      • Genotypes 3 and 4 circulate in pigs but can infect humans
    • HEV-C circulates in rodents and ferrets
  • Genus Piscihepevirus, which infects the cutthroat trout and is not of clinical interest
• Four genotypes, g1 through g4

Epidemiology

• Present globally
• g1 and g2 are more common in developing countries
  • Cause epidemic hepatitis
  • Transmitted fecal-orally
  • Associated with contaminated water and poor sanitation
• g3 and g4 more common in the North America and Europe
  • Zoonoses associated with pigs; humans are incidental hosts
  • Most severe infections in pregnant women
• May also be transmitted by transplant or transfusion

Clinical Manifestations

• Incubation period of about 4 to 6 weeks
• Flu-like prodrome lasting 1 to 10 days with a low-grade fever, followed by hepatitis
• May develop pale stools, dark urine, and jaundice
• Hepatomegaly and sometimes splenomegaly
  • Cholestasis more common in pregnant women
• Liver enzyme abnormalities, over 1000 initially, and hyperbilirubinemia
• Usually self-limited, but some patients progress to fulminant hepatitis
• In immunocompromised patients, may lead to chronic infection and cirrhosis
• Particularly high mortality rate in pregnant women (25% in third trimester)