title: TT virus prevalence, viral loads and genotypic variability in saliva from healthy Japanese children.
abstract: OBJECTIVE
  TT virus (TTV) is genetically variable and widespread without apparent pathogenicity; however, its epidemiological features in children were not fully understood, partly because blood sampling is often unacceptable for healthy children. We therefore used saliva specimens to investigate epidemiology of TTV infection in early childhood.
  
  
  METHODS
  Saliva samples were collected from 83 1-month-old, 110 4-month-old and 49 42-month-old children. Peripheral blood mononuclear cells (PBMC) and saliva samples were obtained in pairs from 19 healthy adults aged 40 +/- 7 years. TTV DNA was detected and quantified by real-time PCR and classified into five genogroups (G1-G5) by a series of PCRs using genogroup-specific primer pairs.
  
  
  RESULTS
  TTV DNA was detected in 6, 34 and 90% of children aged 1, 4 and 42 months, respectively, and in 84% of adults. Comparable levels of TTV DNA were detected in pairs of saliva and PBMC. TTV loads in saliva were much higher in children than in adults. G3 was the most common genogroup in all age groups. The second most prevalent was G4 at 1-4 months of age and G1 thereafter.
  
  
  CONCLUSIONS
  The prevalence of TTV infection reached a plateau at or before 42 months; however, somehow different epidemiologic features were observed among genogroups.
authors.affiliation: Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan. macha.naganuma@nifty.ne.jp
authors.forename: Masako
authors.initials: M
authors.lastname: Naganuma
authors.forename: Norio
authors.initials: N
authors.lastname: Tominaga
authors.forename: Tsunetake
authors.initials: T
authors.lastname: Miyamura
authors.forename: Atsushi
authors.initials: A
authors.lastname: Soda
authors.forename: Masako
authors.initials: M
authors.lastname: Moriuchi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Moriuchi
mesh_terms: D000328:Adult; D000367:Age Factors; D002675:Child, Preschool; D004266:DNA Virus Infections / Q000097:blood / Q000453:epidemiology / Q000235:genetics / Q000821:virology*; D005260:Female; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D007223:Infant; D007564:Japan; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012463:Saliva / Q000821:virology*; D022783:Torque teno virus / Q000235:genetics / Q000302:isolation & purification*; D019562:Viral Load