Short communicationMolecular detection and genomic characterization of Torque teno canis virus in domestic dogs in Guangxi Province, China

- We detected five complete genomes of Torque teno canis virus in dogs in China.
- Overall prevalence of Torque teno canis virus infection was 7%.
- The sequence identity was 94.6%-96.8% among the five genomes.
- Torque teno canis virus and canine parvovirus co-infection exists in China.
- Torque teno canis virus should be as a member of the Thetatorquevirus.

The Torque teno canis virus (TTCaV) is a small virus with circular single-stranded DNA that has been reported to cause infections in dogs. The present study aimed to identify the presence of TTCaV in blood samples obtained from domestic dogs, and examine its diversity and evolution of the genomes. Five strains of TTCaV were detected, and the overall prevalence was found to be 7% (28/400). Phylogenetic analysis showed that the five genomes were closely clustered with the previously known Cf-TTV10 and LDL strains and formed a Thetatorque virus. Homology analysis of the whole genome showed a sequence identity of 94.6%-96.8% among the five genomes. The percent sequence similarity among the five complete genomes ranged from 95.3% to 97.4% and from 95.1% to 97% compared to the Cf-TTV10 and LDL strains respectively. The ORF1-encoded amino acid sequences showed 94.4%-97.2% identity among the five isolates. Our findings suggest that the TTCaV has a large genetic diversity and showed that TTCaV and canine parvovirus (CPV) co-infection exists in China. Further studies on the pathogenicity of TTCaV are required.