TT virus infection among IVDUs in South western China

To elucidate the prevalence and clinical implications of infection with the newly described TT virus (TTV) among intravenous drug users (IVDUs) in Yun nan, southwest China, serum samples from 158 IVDUs (129 M, 29 F; mean age 2 6.1 +/- 5.5 years) mere examined for TTV DNA by semi-nested polymerase chai n reaction (PCR) using primers derived from the open reading frame (ORF1) o f TTV DNA, The seroprevalence of viral markers of HIV, HBV, HCV and GB viru s C/hepatitis G virus (GBV-C) infection was also examined. A molecular evol utionary analysis was performed, Thirty one (20%) of the IVDUs were positiv e for TTV DNA, and 34 (22%), 6 (4%), 98 (62%), 76 (48%), 136 (86%) and 65 ( 41%) were positive for anti-HIV, HBsAg, anti-HBs, anti-HBc, anti-HCV and GB V-C RNA, respectively. When all the subjects were classified according to T TV DNA positivity, no significant differences mere observed in demographic, biochemical or virological characteristics between the 2 groups. TTV infec tion was in all cases associated with co-infection with 1 or more of the ot her aforementioned viruses. There were no significant differences in the va rious combinations of co-infection between TTV positive and negative groups . Phylogenetic analysis revealed that the TTV isolates obtained in the stud y could be grouped mainly into TTV genotype 1, and that some of the isolate s belonged to subgroups other than those previously described. These result s indicate that: 1) TTV infection is prevalent among IVDUs in China; 2) TTV probably has minor liver pathogenicity; and 3) new subgroups of genotype 1 and 2 exist in China.