Hepatitis E.

With the introduction of new, albeit noncommercial, diagnostic tests for the detection of HEV, our understanding of this virus has been greatly enhanced. With these tests, it has been possible to begin a delineation of the process of pathogenesis in infected humans. These tests have also shown us that, at least in some individuals, an IgG response to HEV is long lasting and may confer immunity, and it may be possible to develop a recombinant vaccine against HEV. Contrary to past results, HEV appears to be the most common cause of acute sporadic hepatitis in pediatric populations in endemic regions. HEV has been shown to be a positive-sense single-stranded RNA virus that has been tentatively classified as a calicivirus, although its nonstructural proteins exhibit sequence similarity to rubella virus and furoviruses. Despite these advances in our understanding of HEV, it is still necessary to depend on exclusion of hepatitis caused by other viruses to diagnose a hepatitis E infection; however, this situation should change with the anticipated release of commercially available diagnostic tests.