tt virus infection among iranian blood donors: its prevalence and relationship to serum alanine aminotransferase (alt) level

introduction and aims: tt virus (ttv) is a dna virus and is proposed as a potential cause of non-a to e hepatitis. we aimed to investigate, for the first time, the prevalence of ttv in iranian healthy blood donors. materials and methods: three hundred and twelve healthy iranian blood donors were randomly selected and tested for ttv dna by the seminested polymerase chain reaction method. serum alanine aminotransferase (alt) levels were determined in those infected and uninfected individuals that adequate serum were available. hbsag or hcv antibody-positive subjects were excluded. results: tt virus dna was detected in 70 (22.4%) of the 312 subjects under study. alt was elevated in 8 (18.2%) of the 44 ttv positive blood donors and in 8 (10.9%) of the 73 ttv negative blood donors. there was no significant difference between these two groups. conclusions: ttv viremia is common among iranian blood donors. its prevalence in iran is higher than us (1%) and most west-european countries and is comparable to china (28%) but lower than thailand (37%) and italy (42.4%). our data do not support the correlation between ttv viremia and elevated alt level.