Coinfection with Multiple TT Virus Strains Belonging to Different Genotypes Is a Common Event in Healthy Brazilian Adults

Testing of the DNA of TT virus (TTV) was done with serum samples obtained from 191 persons working in a public hospital of the city of Rio de Janeiro, Brazil. TTV DNA was detected by PCR in the sera of 125 (65.4%) individuals. PCR products were cloned, and sequences with a length of 159 bases surrounding the TATA signal region were determined for 100 clones derived from 31 individuals. One clone from each of 23 subjects was sequenced, while 7 to 19 clones from eight individuals were sequenced. None of the sera contained a viral sequence identical to that of any other individual. Phylogenetic analysis revealed the existence of a divergent TTV genotype possessing a single-base deletion at position 140. Among the eight persons for whom various sequences were analyzed, six were coinfected with between two and seven TTV strains belonging to different genotypes. The results suggest that coinfection with multiple TTV strains belonging to different genotypes is a common event in healthy Brazilian adults.