Related TT viruses in chimpanzees

A series of serum specimens obtained from two chimpanzees experimentally in fected with hepatitis A virus (HAV), hepatitis C virus, and hepatitis G/GB- C virus were tested for TT virus (TTV) by polymerase chain reaction (PCR). All PCR fragments obtained from both animals were directly sequenced, and t he nucleotide sequences were compared to each other and to all known TTV se quences. This comparison showed that both animals were infected simultaneou sly with four new TTV variants designated A, M1, M2, and M3. One chimpanzee was found to be infected with TTV only after HAV inoculation, whereas the other animal was infected with TTV before any experimental procedure was pe rformed. A set of PCR primers specific for these four new TTV variants was used to amplify TTV-like sequences from nine naive chimpanzees. None of the se animals was infected with the prototype TTV variant. Two of these animal s, however, were infected with one of the new TTV variants, while one anima l was infected with an additional new TTV variant designated T. Among 99 he patitis patients, 29 were found to be infected with the prototype TTV varia nt. None of these human specimens was found to be positive by PCR specific for TTV variants A, M1, M2, and M3. Similarly, not a single specimen from a smaller subset of human serum samples was found to be positive for the TTV variant T. Phylogenetic analysis performed on all known TTV sequences demo nstrated that TTV, can be classified into 13 different, yet closely related TTV species, designated as TTV-I for the prototype variant through TTV-XII I. The new variants M1 and M2 were classified as two different genotypes of TTV-VI, variant M3 was classified as TTV-VII, variant A was classified as TTV-VIII, and variant T was classified as TTV-IX. Thus, the data obtained i n this study suggest that TTV represents a large swarm of TTV-like species, some of which have not been detected in humans and circulate predominantly among chimpanzees. (C) 2000 Academic Press.