The history of infectious hepatitis illustrates the ever-challenging battle between humans, micro-organisms, and disease. In the 1970s the organisms causing viral hepatitis type A and B were identified, allowing more accurate diagnosis and treatment, and the battle seemed to be on the way to being won. But nature persisted, and the term non-A non-B hepatitis was coined for the viral liver disease not due to hepatitis A or B virus, cytomegalovirus, or Epstein-Barr virus. Without specific assays the diagnosis of non-A non-B hepatitis was based on exclusion. The disorder accounted for 75-90% of cases of post-transfusion hepatitis, but it also included enterically transmitted, sporadic, endemic, and community acquired disease.1 In developed countries this type of hepatitis is second only to alcohol as a cause of chronic liver disease, cirrhosis, and hepatocellular carcinoma, but its treatment remains problematic.2

Most non-A non-B hepatitis is due to a single virus, hepatitis C virus, and with cloning of its virion, a positive single stranded RNA molecule,3 the diagnosis of liver disease became more reliable. Further precision came with assays for specific antibodies to hepatitis C4 and, more recently with identification of hepatitis C virus RNA in the serum by reverse transcriptase polymerase chain reaction - a marker for viraemia and the infectious state.5

Three papers in …