Molecular Medical Microbiology, 3rd Edition - Chapter 113: Viral hepatitis A and E

Hepatitis A and E remain a major threat to public health in the world. The etiologic agents responsible for these diseases are hepatitis A virus (HAV) and hepatitis E virus (HEV), respectively; both are small RNA viruses that are transmitted enterically but replicate mainly in hepatocytes. The disease caused by HAV and HEV is clinically indistinguishable and usually self-limited. In addition, HAV and HEV have several remarkable similarities in their life cycle and immune evasion strategies yet have important differences in epidemiology and clinical landscape. Unlike HAV, which is only found in humans, certain HEV genotypes have a zoonotic origin and are able to cause chronic infection in individuals with a weakened immune system. In addition, HEV infection is associated with a range of extrahepatic manifestations. Improved hygiene and the use of highly effective vaccines have largely eliminated hepatitis A cases in developed countries, and a highly effective hepatitis E vaccine is available (currently licensed only in China) and may be used for high-risk groups. There is no specific antiviral therapy for either HAV or HEV, although ribavirin has been successfully used in treating patients with chronic hepatitis E.