Hepatitis G Virus Infection: A Work in Progress

Before the hepatitis C virus (HCV) was identified in 1989, there was speculation about the existence of more than one blood-borne viral agent causing non-A, non-B hepatitis [1]. This speculation has continued and is supported by evidence of several unexplained hepatitis-associated syndromes, including cryptogenic hepatitis and cirrhosis, fulminant hepatic failure of unknown cause, and aplastic anemia. None of these syndromes is clearly linked to any of the known hepatitis viruses. Thus, great interest was generated when separate groups of investigators announced the discovery of new hepatitis viruses in 1995 [2-4]. Both discoveries were made by industry-based investigators who collaborated with researchers at academic and government institutions.

Researchers at Abbott Laboratories isolated three viral agents from the serum of a tamarin that was inoculated with serum from a surgeon who had contracted hepatitis and had been studied more than 20 years ago [2, 3, 5]. Because this surgeon's initials were GB, the researchers named the viral isolates after him as follows: GBV-A, GBV-B, and GBV-C. They found that GBV-A and GBV-B were probably tamarin agents incidentally infecting the animals used for inoculating the original GB serum and that GBV-C was the most likely viral hepatitis candidate in humans. At about the same time, researchers at Genelabs Technologies, Inc., announced that they, too, had discovered a new hepatitis virus, isolated from the serum of a patient with community-acquired non-A, non-B hepatitis [4]. This patient was initially thought not to be infected with HCV; more …