The TT virus - Literature review

Objective: To review the litterature on the TT virus. Methods: The litterature review was based on articles identified through ME DLLNE between Jan. 1, 1997, and August 15, 1999. Results: In 1997, a new DNA virus, designated TTV, was isolated and seemed to be associated with non A-G post-transfusion hepatitis. The virus was ide ntified using a polymerase chain reaction (PCR) because serology was not ro utinely available. At least 16 genotypes were identified. Depending on the PCR technique used, the prevalence of infection ranged from 17% to 71% in a group of sera tested. The prevalence rate ranged from 1.2% to 62% among bl ood donors, from 0.5% to 83% among hemophiliacs and from 1% to 71% in cases of chronic hepatitis. The current hypothesis is that routes of infection w ere parenteral and orofecal. The pathogenesis of this virus, if it really e xists, is not yet clearly established. It has been postulated that some int eraction may exist between the TT virus and the hepatitis C virus. The use of interferon seems to decrease the TT viremia, according to results obtain ed outside the context of clinical trials. Conclusion: The pathogenesis of the TT virus needs to be rapidly establishe d for transmission prevention and therapeutic intervention.