[The TT virus: review of the literature].
OBJECTIVE
To review the literature on the TT virus.


METHODS
The literature review was based on articles identified through MEDLINE 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 identified using a polymerase chain reaction (PCR) because serology was not routinely 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 blood 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 were parenteral and orofecal. The pathogenesis of this virus, if it really exists, is not yet clearly established. It has been postulated that some interaction may exist between the TT virus and the hepatitis C virus. The use of interferon seems to decrease the TT viremia, according to results obtained outside the context of clinical trials.


CONCLUSIONS
The pathogenesis of the TT virus needs to be rapidly established for transmission prevention and therapeutic intervention.
Laboratoire d'épidémiologie et de santé publique, Université Claude Cernard, Lyon, France.
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M
Dhenain
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A
Boulétreau
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F
Bourguignon
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Poujol
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Chemin
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Fabry
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Vanhems
D004266:DNA Virus Infections / Q000453:epidemiology / Q000517:prevention & control / Q000635:transmission; D004279:DNA, Viral / Q000032:analysis; D005838:Genotype; D006525:Hepatitis, Viral, Human / Q000635:transmission; D006801:Humans; D016239:MEDLINE; D016133:Polymerase Chain Reaction; D022783:Torque teno virus / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology; D065227:Transfusion Reaction; D014766:Viremia
D004279:DNA, Viral