title: Molecular investigation of Torque teno sus virus in geographically distinct porcine breeding herds of Sichuan, China.
abstract: BACKGROUND
  Torque teno sus virus (TTSuV), infecting domestic swine and wild boar, is a non-enveloped virus with a circular, single-stranded DNA genome. which has been classified into the genera Iotatorquevirus (TTSuV1) and Kappatorquevirus (TTSuV2) of the family Anelloviridae. A molecular study was conducted to detect evidence of a phylogenic relationship between these two porcine TTSuV genogroups from the sera of 244 infected pigs located in 21 subordinate prefectures and/or cities of Sichuan.
  
  
  RESULTS
  Both genogroups of TTSuV were detected in pig sera collected from all 21 regions examined. Of the 244 samples, virus from either genogroup was detected in 203 (83.2%), while 44 animals (18.0%) were co-infected with viruses of both genogroups. Moreover, TTSuV2 (186/244, 76.2%) was more prevalent than TTSuV1 (61/244, 25%). There was statistically significant difference between the prevalence of genogroups 1 infection alone (9.4%, 23/244) and 2 alone (64.8%, 158/244), and between the prevalence of genogroups 2 (76.2%, 186/244) and both genogroups co-infection (18.0%, 44/244). The untranslated region of the swine TTSuV genome was found to be an adequate molecular marker of the virus for detection and surveillance. Phylogenetic analysis indicated that both genogroups 1 and 2 could be further divided into two subtypes, subtype a and b. TTSuV1 subtype b and the two TTSuV2 subtypes are more prevalent in Sichuan Province.
  
  
  CONCLUSIONS
  Our study presents detailed geographical evidence of TTSuV infection in China.
authors.affiliation: Animal Biotechnology Center, College of Veterinary Medicine, Sichuan Agricultural University, Ya'an 625014, China.
authors.forename: Miao
authors.initials: M
authors.lastname: Mei
authors.forename: Ling
authors.initials: L
authors.lastname: Zhu
authors.forename: Zhiwen
authors.initials: Z
authors.lastname: Xu
authors.forename: Ling
authors.initials: L
authors.lastname: Zhao
authors.forename: Yuancheng
authors.initials: Y
authors.lastname: Zhou
authors.forename: Yunfei
authors.initials: Y
authors.lastname: Wu
authors.forename: Song
authors.initials: S
authors.lastname: Li
authors.forename: Haoche
authors.initials: H
authors.lastname: Wei
authors.forename: Wanzhu
authors.initials: W
authors.lastname: Guo
mesh_terms: D000818:Animals; D002681:China; D004266:DNA Virus Infections / Q000662:veterinary* / Q000821:virology; D004279:DNA, Viral / Q000737:chemistry / Q000235:genetics; D008969:Molecular Sequence Data; D058974:Phylogeography; D011110:Polymorphism, Genetic; D017422:Sequence Analysis, DNA; D044967:Serum / Q000821:virology; D013552:Swine; D022783:Torque teno virus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D004279:DNA, Viral