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
- 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)
