Seroepidemiology of TT virus infection and relationship between genotype and liver damage

TT virus (TTV) has been identified in patients with posttransfusion hepatit is of unknown etiology and is thought to be a new hepatitis virus. We deter mined the extent of TTV infection in the Japanese general population and th e relationship between TTV DNA genotype and liver damage. In 1998, we teste d 847 serum samples for TTV. TTV DNA was assayed by a nested polymerase cha in reaction and classified into three different genotypes and eight subtype s. TTV DNA was detected in 25.3% and 32.4% of the inhabitants of the two ar eas studied, respectively. The genotype distribution was similar in both ar eas. G1, G2, and G3 were 60%, 20%, and 5%, respectively. Of the 20 subjects with TTV DNA alone and elevated serum ALT levels, 18 were G1, one was G2, and one was G3, TTV infection is endemic in the Japanese general population studied. The main TTV genotype, G1, may be related to the ensuing liver da mage.