First Molecular Detection of Torque Teno Canis Virus in Apparently Healthy Dogs in Southern Italy

Torque teno viruses are viruses with unclear pathogenic potential, as conflicting evidence has classified this family of viruses as harmless and opprtunistic. Dogs also have their own specific Torque teno virus, called Torque teno canis virus (TTCaV), which has been reported in several countries.

This study aimed to identify TTCaV in the feces of apparently healthy dogs and to evaluate risk factors correlated to higher prevalences.

Faecal samples were collected from 171 dogs from the Campania region, Italy. DNA was extracted from each sample and used as a template in a nested end-point PCR, and some positive samples were sequenced by the Sanger method. Univariate analysis was performed to assess the correlation between molecular detection of TTCaV and variables included in the study.

A total of 18 out of 171 animals (10.5%) were PCR-positive. No individual factor (sex, age, etc.) was associated with higher prevalence, while significant differences were observed in mixed-breed (16.5%) and kennel dogs (17.7%). Although the identification of TTCaV DNA was more frequent in dogs with an altered faecal score (score > 2 on a 1-7 scale), we did not find higher prevalence in CPV-2-positive animals (even if based on only 11 CPV-2-positive samples). A total of six amplicons were sequenced, obtaining two different isolates that, once deposited in international databases and compared with those reported in other studies, showed a homology with other strains identified worldwide.

Although questions concerning the clinical relevance of TTVs still remain unanswered, our study documented the presence of this virus in the dog population in southern Italy. Moreover, our work provided phylogenetic data and useful information to better characterize the epidemiological picture of this virus in Italy and in Europe.