High frequency and extensive genetic heterogeneity of TTSuV1 and TTSuVk2a in PCV2- infected and non-infected domestic pigs and wild boars from Uruguay

Abstract

Torque teno sus virus (TTSuV) infection is common worldwide in both healthy and diseased swine and a relationship between this virus and a particular disease in pigs has not been established. This work aimed to investigate the presence of TTSuV1 and TTSuVk2a in Porcine Circovirus type 2 (PCV2)-infected and non-infected domestic pigs and free-living wild boars from Uruguay. Our data evidenced a high frequency of detection and a wide circulation of TTSuV among pig herds and wild boar populations. Furthermore, TTSuV1+TTSuVk2a co-infection was more frequent than single infections in domestic pigs. In addition, we thoroughly characterized at the molecular level TTSuV strains by extensive sequence data analysis. Our findings revealed an extremely high genetic heterogeneity among Uruguayan isolates. On the basis of detailed analyses, we proposed a more comprehensive criterion of TTSuV classification which would contribute to shedding light over the genetic diversity of these viruses worldwide. On the other hand, data obtained suggested that neither TTSuV1 nor TTSuVk2a frequency of infection or viral loads have any correlation with PCV2 infection, health status or age. The role of TTSuV during co-infection with other pathogens and the age-related dynamics of TTSuV infection are currently under debate. Therefore, taking into account the controversial epidemiological data regarding these viruses and their ubiquitous infection, a likely role as components of the host microbiota should be brought into discussion.