title: Molecular epidemiology and genotyping of TT virus isolated from Saudi blood donors and hepatitis patients.
abstract: BACKGROUND
  In Saudi Arabia, the epidemiology and clinical significance of Torque Teno virus (TTV) infection alone and in patients with hepatitis virus infections have not been determined in a single study. In this paper, we molecularly investigated the rate and genotypes of TTV infection among Saudi Arabian blood donors and patients with viral hepatitis. The effect of TTV coinfection on viral hepatitis was also examined.
  
  
  METHODS
  DNA was extracted from the sera of 200 healthy blood volunteers, 45 hepatitis B virus patients, 100 hepatitis C virus patients, 19 hepatitis G virus patients, and 56 non-A-G hepatitis patients. TTV DNA was amplified using primers derived from the ORF1 and 5'UTR regions. The alanine aminotransferase (ALT) level was determined for each specimen. Sequencing of ORF1 amplicons was carried out to investigate TTV genotypes.
  
  
  RESULTS
  Using primers derived from ORF1 and 5'UTR, TTV DNA was detected in 5.5% and 50.5%, respectively, of healthy blood donors, in 2.2% and 88.8% in hepatitis B patients, in 2.0% and 70% of hepatitis C patients, in 15.8% and 100% of hepatitis G patients, in 5.4% and 12.5% of non-A-G hepatitis patients and in 4.8% and 56.4% overall. No detrimental effect of TTV coinfection in viral hepatitis patients was noted. An overall prevalence of 4.8% and 56.4% was established. Phylogenetic analysis indicated that the most common genotype of TTV among Saudis is 2c.
  
  
  CONCLUSIONS
  The rate of TTV infection among Saudi Arabians seems to be lower than that stated in previous reports on Saudi Arabia and in some other countries. The virus does not seem to worsen the status of those who are suffering from viral hepatitis infection.
authors.affiliation: Department of Biological and Medical Research, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.
authors.forename: Maha A
authors.initials: MA
authors.lastname: Al-Mozaini
authors.forename: Mohammed N
authors.initials: MN
authors.lastname: Al-Ahdal
authors.forename: George
authors.initials: G
authors.lastname: Kessie
authors.forename: Damian M
authors.initials: DM
authors.lastname: Dela Cruz
authors.forename: Mohammed A
authors.initials: MA
authors.lastname: Rezeig
authors.forename: Fahad J
authors.initials: FJ
authors.lastname: Al-Shammary
mesh_terms: D000410:Alanine Transaminase / Q000097:blood; D001782:Blood Donors; D017931:DNA Primers; D004266:DNA Virus Infections / Q000821:virology*; D004279:DNA, Viral / Q000097:blood; D005838:Genotype; D006525:Hepatitis, Viral, Human / Q000097:blood / Q000821:virology*; D006801:Humans; D008099:Liver / Q000821:virology; D008969:Molecular Sequence Data; D010802:Phylogeny; D012529:Saudi Arabia; D022783:Torque teno virus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D014764:Viral Proteins / Q000235:genetics
chemical_list: D017931:DNA Primers; D004279:DNA, Viral; C446939:ORF1 protein, TT virus; D014764:Viral Proteins; D000410:Alanine Transaminase