Hepatitis E virus (HEV) was first identified in 1980 as a new hepatitis pathogen found primarily in Asia, Africa and South America. Although the clinical presentation is similar to HAV, HEV is more severe; HEV results in a 1-2% death rate and is often associated with fulminant hepatic failure in pregnant women and an increased risk of mortality in the third trimester. HEV antibody responses peak at about one month after initial infection. Antiviral IgM is detected in >90% of patients and persists for 3 months. Anti-HEV IgM is also a well-established marker of recent infection and is the most convenient one for diagnosis.