Table 1.

Comparison of HAV and HEV characteristics in the United States

Additional considerations	HAV	HEV
Viral taxonomy (family, genus)	Picornaviridae, Hepatovirus	Hepeviridae, Orthohepevirus
Primary route of transmission	Fecal–oral	Zoonotic (foodborne)
Zoonotic reservoir	No	Pigs, boars, and deer
Chronic infection	No	Yes, among immunocompromised persons
Severity	Generally mild, self-limited acute illness Increased severity with increased age at infection and in persons with preexisting liver disease Acute liver failure possible, but rare	Most infections are clinically silent When symptoms occur, illness is generally mild and self-limited Increased severity in pregnant women and persons with preexisting liver disease Acute liver failure possible, but rare

HAV, hepatitis A virus; HEV, hepatitis E virus.