Prevalence and phylogenetic characterisation of TT-virus in the blood donor population of Auckland, New Zealand

TT-virus (TTV, patient initials: T.T.), a novel DNA virus, was first isolat ed in Japan in 1997 from serum of a patient with post-transfusion hepatitis of unknown aetiology. To date, the contribution of TTV to liver disease re mains doubtful. The potential for transmission via brood and blood products makes it essential to establish the prevalence of TTV viraemia in the bloo d donor population. 413 blood donor serum samples were chosen randomly, the DNA was extracted and TTV-specific DNA amplified by nested polymerase chai n reaction (PCR). TTV infection was present in 13 out of 413 (3.15%) blood donors in the Auckland region of New Zealand using a set of primers targeti ng open reading frame (ORF) 1. These 13 amplification products (264 bp) wer e sequenced and TTV genotypes determined. Alignment with published TTV sequ ences showed that seven (53.8%) of the thirteen positive serum samples belo nged to genotype 1,five (38.5%) belonged to genotype 2 and one (7.7%) could not be classified as either genotype 1 or 2. One hundred twenty-seven bloo d donor serum samples were retested with a second set of primers targeting the 5' region of the TTV genome in a single round PCR. Forty-three samples were positive for TTV DNA with these primers resulting in a prevalence of 3 7%. The data demonstrate that TTV is present among New Zealand blood donors and support the need for further investigation into the natural history of TTV infection. J. Med. Virol. 62:109-114, 2000. (C) 2000 Wiley-Liss, Inc.