TT virus infection in an area of high-endemicity for hepatitis C

Abstract TT virus (TTV) was recently identified as a candidate for a new hepatitis virus. In the present study, the clinical features and transmission routes of TTV infection were analyzed in an area highly endemic for hepatitis C virus (HCV) infection, and compared to those in an area not endemic. A total of 400 inhabitants were selected randomly from those who were medically screened for liver disease in 1993; 200 were from the high-endemicity area, and the other 200 were from the control area. TTV DNA in serum was tested by a semi-nested polymerase chain reaction. The prevalence of TTV DNA was 58% (116/200) in the high-endemicity area, and was significantly ( P =0.0083) higher than that in the control area (43%, 85/200). Age specific prevalence of TTV DNA was significantly ( P =0.0007) higher in individuals over 60 years old (68.8%) than in those under 60 (45.1%) in the high-endemicity area, but was similar among the age groups in the control area. TTV infection was not associated with neither HCV and hepatitis G virus (HGV) infections nor histories of surgical operation, blood transfusion and folk remedies in both areas. In the high-endemicity area, the prevalence of TTV DNA was significantly ( P =0.0311) lower in individuals with any HCV markers (25%) than in those without it (39%). The elevation of liver enzymes in serum was dependent on HCV viremia but not on TTV viremia. In conclusion, the prevalence of TTV infection was as high as 58% in the high-endemicity area for HCV infection. The infection pattern for TTV was different from that of HCV and HGV. TTV infection showed a reciprocal association with HCV infection, and had limited pathogenetic effect on hepatitis.