Discovery of a novel Torque teno sus virus species: genetic characterization, epidemiological assessment and disease association

Abstract

The study describes a novel Torque teno sus virus (TTSuV) species, provisionally named Torque teno sus virus k2b (TTSuVk2b), originally found in commercial pig sera by applying the rollingcircle amplification technique. Full-length sequences of TTSuVk2b were obtained, annotated and used in the phylogenetic analyses, which revealed that TTSuVk2b is a novel Anellovirus species within the genus Kappatorquevirus of the family Anelloviridae. Quantitative PCR techniques were developed to determine total TTSuV DNA quantities as well as the prevalence and viral DNA quantities of TTSuV1, TTSuVk2a and TTSuVk2b. The mean total TTSuV load in seven commercial sera was determined at 6.3 log 10 DNA copies ml "1 of serum, with TTSuVk2b loads being the lowest at 4.5 log 10 DNA copies ml "1 of serum. Subsequently, prevalence and loads of TTSuVs were determined in pig sera from 17 countries. TTSuVk2b prevalence ranged from 0 to 100 % with viral loads from 3.3 to 4.6 log 10 copies ml "1 of sera. TTSuVk2a, so far the only species in the genus Kappatorquevirus, has been linked to an economically important swine disease, namely post-weaning multisystemic wasting syndrome (PMWS). Considering the grouping of TTSuVk2b in the same genus as TTSuVk2a, TTSuVk2b prevalence and viral DNA load were determined in PMWS-affected animals and healthy counterparts. This revealed that TTSuVk2a and TTSuVk2b are not only genetically related, but also that their viral loads in serum are elevated in PMWS animals compared with those of healthy pen mates. In summary, the present work describes a novel TTSuV species including its genetic characterization, epidemiological assessment and potential disease association.

Application of a pathogen microarray for the analysis of viruses and bacteria in clinical diagnostic samples from pigs

“…The strongest connection between TTSuV and disease is as a cofactor in PCV-2-associated syndromes. 6 PCV-2 and TTSuV have been previously identified together in association with PMWS. 34 Interestingly, TTSuV was found in most serum samples, including all 6 PCVAD pigs, and was found in the tonsils of 3 pigs removed at 32 dpi because of morbidity associated with PCVAD.…”

Global impact of Torque teno virus infection in wild and domesticated animals

“…Data related to infection with TTSuVk2b, the most recently identified species, are still limited. A study on 244 pig serum samples from 17 different countries reported an overall 40% prevalence of infection [36], whereas Blois et al reported an 11.5% prevalence of TTSuVk2b in 721 Italian pigs [70]. The high prevalence of TTSuV in the swine population indicates the existence of effective mechanisms of transmission.…”

“…In addition to TTV, in humans there are two other TTV-like species: TTMV and TTMDV, classified within the family Anelloviridae and belonging to the genera Betatorquevirus and Gammatorquevirus, respectively. TTVs infecting pigs (Sus domesticus) include four species described so far: Torque teno sus virus 1a and 1b (TTSuV1a and TTSuV1b), belonging to the genus Iotatorquevirus, and Torque teno sus virus k2a and k2b (TTSuVk2a and TTSuVk2b), the latter being the most recently discovered species, belonging to the genus Kappatorquevirus [36].…”

Preliminary epitope mapping of Torque teno sus virus 1 and 2 putative capsid protein and serological detection of infection in pigs

“…Although it seems that TTSuV infection is not directly responsible for any disease, the possibility remains that they play a role in different co-infections (Cornelissen-Keijsers et al, 2012;Taira et al, 2009). …”

“…Viral prevalence increases with age and in most animals the infection can be persistent (Sibila et al, 2009a, b;Taira et al, 2009). New porcine TT virus species (named TTSuV1a and TTSuV1b) have been proposed based on new sequence data (Cornelissen-Keijsers et al, 2012).…”