[HGV, TTV and SEN viruses--are these organisms pathogenic?].

After the discovery of hepatitis A, B, C, D and E viruses, several lines of evidence suggested that an additional hepatitis agent (s) might exist. Molecular approaches led sequentially to the discoveries of GBV-C/HGV, TTV and more recently SENV. At issue is whether these agents cause non - A non - E hepatitis and/or some extrahepatic diseases. These problems are discussed in present paper, considering the newest data from literature.