Molecular detection of Torque teno virus in different breeds of swine

BACKGROUND: Torque teno virus (TTV), of the Anelloviridae family, Iotatorquevirus genus, is a non-enveloped, single-stranded, and negative sense DNA (ssDNA) virus infecting human and many domestic animals including swines. Very little information is known about the investigations of TTV prevalence in different swine breeds so far. METHODS: In this study, 208 serum samples collected from seven swine breeds (Rongchang pig, Chenghua pig, Zibet pig, Wild boar, Duroc, Landrace, Large Yorkshire) from two independent farms were detected to determine the prevalence of two swine TTV genogroups, TTV1 and TTV 2, by nested polymerase chain reaction methods, and to analyse prevalence difference among these breeds. RESULTS: The results showed that the prevalence of TTV in the seven breeds was 92%-100%. No significant difference (p > 0.05) in TTV infection was observed between different breeds. Interestingly, significantly higher prevalence for TTV1 in Rongchang boars (90%) and for TTV2 in Rongchang sows (95%) were detected, while co-infection rate (43.8%) was lower than other breeds. Sequence analysis showed that the homology of TTV1 and TTV2 were over 90.9% and 86.4% in these breeds, respectively. CONCLUSIONS: The results indicated that TTV was widely distributed in the seven swine breeds. The prevalence of both TTV genogroups associated with swine breeds and genders. This study also respented the first description of swine TTV prevalence in different swine breeds. It was vitally necessary to further study swine TTV pathogenicity.