High prevalence of TT virus infection in Brazilian blood donors

A recent report has described the molecular cloning and characterization of a novel, single-stranded DNA virus, named TT virus (TTV), which was presen t in the sera of Japanese patients with posttransfusion hepatitis of unknow n etiology [Okamoto et al. (1998) Hepatology Research 10:1-16]. Using a nes ted polymerase chain reaction assay, sera from Brazilian patients with acut e non A-C hepatitis and blood donors were examined for the presence of TTV DNA sequences. Thirty-seven of 52 (71%) patients with acute non A-C hepatit is and 45 of 72 (62%) blood donors were found to have TTV sequences in thei r sera. Such a high proportion in blood donors indicated that TTV infection is common in the general Brazilian population. Partial nucleotide sequence s (326 bases in open reading frame 1) from seven isolates were determined. By phylogenetic analysis, four TTV strains were classified into the genomic subgroup G1a described previously. The three others belonged to subgroup G 1b. Sequence homologies between strains belonging to a same subgroup were 9 2.9-99.1%, whereas homologies of 85.9-90.2% were calculated between isolate s from different subgroups. J. Med. Virol. 57:259-263, 1999. (C) 1999 Wiley -Liss, Inc.