Torque teno sus virus (TTSuV) in tissues of pigs and its relation with the occurrence of postweaning multisystemic wasting syndrome

Torque teno sus virus (TTSuV) is a member of the recently created family Anelloviridae . Two distinct species of TTSuVs, 1 (TTSuV1) and 2 (TTSuV2) have been reported so far in domestic pigs and wild boars. Although TTSuVs have not been clearly linked to any specific disease of pigs, a relation between TTSuV infections and postweaning multisystemic wasting syndrome (PMWS) has been suggested. To examine further this possibility, the present study was conducted in search for TTSuV1 and TTSuV2 genomes in tissues of PMWS and non-PMWS-affected animals. PMWS diagnosis was established by clinical signs, characteristic macroscopic and histopathologic lesions and the presence of porcine circovirus type 2 DNA. Samples of five different tissues (lungs, kidneys, livers, spleens, and lymph nodes) from PMWS-affected and non-PMWS-affected pigs were examined with two specific PCR assays developed to amplify TTSuV1 and TTSuV2 genome segments. TTSuV1 DNA was detected in tissues of non-diseased animals to significantly higher levels than in tissues of PMWS-affected pigs ( p ≤ 0.001). Regarding TTSuV2, viral genomes were detected in nearly all samples from both PMWS-affected (94.7 %) and non-affected pigs (100 %), with no significant differences in the frequencies of detection of TTSuV2 genomes in both groups. No significant differences were detected on the distribution of TTSuV1 and TTSuV2 in the different tissues examined ( p = 0.970).