TT-virus infection in Japanese general population and in hemodialysis patients.

To determine TT virus (TTV) prevalence and the persistence of viremia, we prospectively did cross-sectional and longitudinal studies using by the polymerase chain reaction to test the successive sera of 150 Japanese hemodialysis patients and compared these with those of 166 residents of a rural Japanese area endemic for hepatitis C virus (HCV). TTV DNA positivity was significantly higher in 50 (30.1%) of the residents than in 25 (16.7%) of the patients in 1997 (P < 0.05). TTV DNA positively in the patients was not associated with HCV RNA positivity and also increased with the number of blood transfusions and decreased with the duration of hemodialysis, but not significantly. Longitudinal study from 1997 to 1999 showed that persistent TTV DNA positivity was found significantly more often in 35 (21.1%) of the residents than in 13 (8.6%) of the patients (P < 0.05), and that persistent TTV DNA negativity was found significantly more often in 103 (68.7%) of the patients than in 91 (54.8%) of the residents (P < 0.05). Of the 25 patients and 50 residents TTV DNA positive in 1997, TTV DNA was eliminated more often in 12 (48.0%) patients than in 15 (30.0%) residents over the three years, but the difference was not significant. The route of TTV transmission might differ from HCV in that it could be nonparenteral. TTV was less prevalent in hemodialysis patients than residents, and the virus was more often eliminated by hemodialysis patients than by residents during the three-year observation period, possibly because of the effect of the hemodialysis procedure.