Prevalence of TT virus infection in US blood donors and populations at risk for acquiring parenterally transmitted viruses

Two overlapping sets of TT virus (TTV)-specific polymerase chain reaction p rimers were used to test for presence of TTV, which was found in approximat ely 10% of US volunteer blood donors, 13% of commercial blood donors, and 1 7% of intravenous drug abusers. The rate of TTV infection among US non-A, n on-B, non-C, non-D, non-E hepatitis patients was only 2%. Among commercial blood donors and intravenous drug abusers, only 1%-3% of the TTV-positive i ndividuals were coinfected with GB virus C (GBV-C), a parenterally transmit ted virus. This suggests that GBV-C and TTV may have different routes of tr ansmission. Comparison of the sensitivities of 2 TTV polymerase chain react ion (PCR) primer sets showed that the majority of samples were detected wit h only 1 of the 2 sets. Therefore, previous studies in which only a single PCR primer pair was used may have significantly underestimated the true pre valence of TTV.