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Viral hepatitis is a systemic disease primarily involving the liver. Most cases of acute viral hepatitis in children and adults are caused by one of the following five agents: hepatitis A virus (HAV), the etiologic agent of viral hepatitis type A (infectious hepatitis); hepatitis B virus (HBV), which is associated with viral hepatitis B (serum hepatitis); hepatitis C virus (HCV), the agent of hepatitis C (common cause of posttransfusion hepatitis); hepatitis D (HDV), a defective virus dependent on coinfection with HBV; or hepatitis E virus (HEV), the agent of enterically transmitted hepatitis. Additional well-characterized viruses that can cause sporadic hepatitis, such as yellow fever virus, cytomegalovirus, Epstein-Barr virus, herpes simplex virus, rubella virus, and the enteroviruses, are discussed in other chapters. Hepatitis viruses produce acute inflammation of the liver, resulting in a clinical illness characterized by fever, gastrointestinal symptoms such as nausea and vomiting, and jaundice. Hepatitis viruses cause similar appearing histopathologic lesions in the liver during acute disease.
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PROPERTIES OF HEPATITIS VIRUSES
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The characteristics of the five known hepatitis viruses are shown in Table 35-1. Nomenclature of the hepatitis viruses, antigens, and antibodies is presented in Table 35-2.
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