Molecular detection of Torque teno virus in different breeds of swine

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.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.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.Torque teno virus (TTV) was first found from a Japanese patient with post-transfusional hepatitis of unknown etiology (non-A-G) in 1997 [1]. TTV is a small, non-enveloped, single-stranded, negative sense, and circular DNA virus, belonging to the Anelloviridae family, Iotatorquevirus genus [2,3]. TTV is frequently detected in humans and swines, but its pathogenicity/virulence and its ability to induce specific diseases are currently unknown [4,5]. However, TTV co-infection with other virus species could be related with such a disease but to date no definitive correlation has been found with any disease syndrome [6-10]. The swine TTV genogroup 2 has been found to be more common in pig suffering from postweaning multisystemic wasting syndrome (PMWS), a disease caused by porcine circovirus type 2 (PCV2), than in non