Hepatitis viruses

The term hepatitis describes an infl ammatory disease of the liver. The most frequent origin worldwide is viral infection, but alcohol, drugs, other toxins, metabolic dis orders, and autoimmune reactions may also cause hepatitis. Acute and chronic courses of viral hepatitis are observed. The clinical symptoms range from asymptomatic forms to fulminant liver failure. Viral hepatitis is mostly caused by the hepatitis viruses A, B, C, D and E, but may also be related to herpesviruses (CMV, EBV and VZV; rarely HSV and HHV6) or adenovirus infection. Besides hepatitis A to E viruses (HAV to HEV), EBV causes hepatitis upon primary infection. In tropical areas, yellow fever virus as well as the hemorrhagic fever viruses (Marburg, Ebola, Lassa, Junin, Machupo, Kyasanur Forest) may cause liver infl ammation. Worldwide more than 350 million people are chronically infected with hepatitis B virus ( HBV) and approximately 130 million with hepatitis C virus ( HCV). Infections have similar clinical presentation; defi nitive diagnosis is dependent on laboratory testing. Besides serological studies, molecular assays are of major importance to confi rm and stage the causative virus. qPCR, which has revolutionized nucleic acid detection by its speed, sensitivity, and reproducibility, is currently applied to the detection and quantifi cation of hepatitis viruses. Quantitative PCR plays a key role in laboratory diagnosis of non-A to -E hepatitis, in determining the risk of transmission, and in monitoring the response to antiviral treatment of hepatitis B, C and D. HBV and HCV genotyping results provide important information to predict the resistance or response to antiviral therapy.