Hepatitis E

Large outbreaks, faecal-oral transmission, and mainly young adults affected

Hepatitis E virus is the latest addition to the list of viruses causing hepatitis. Recently Reyes's group cloned and sequenced the virus1 previously referred to as non-A or epidemic hepatitis because of its propensity to cause large outbreaks.2

A faecally transmitted form of viral hepatitis that was distinct from hepatitis A had long been suspected, and its existence was confirmed in the late 1970s when specific serological tests for hepatitis A virus failed to diagnose many cases of “infectious hepatitis.”3 Virus-like particles were observed in stool samples from infected patients, and the infection was transmissible to experimental animals.4 Lack of supply of antigen hampered the development of convenient serological assays until the viral genome was cloned by Reyes's group.

Only one type of hepatitis E virus exists, although several strains, including those derived from Mexican and Burmese isolates, …