Prevalence and Genetic Diversity of Torque teno felis virus (FcTTV) in Domestic Cats from Kazakhstan.

Abstract

Anelloviruses have a broad mammalian host range, including Torque teno felis virus (FcTTV), a felid-associated member that remains undercharacterized. This is the first comprehensive study of FcTTV in domestic cats in Central Asia. We analyzed blood samples from 206 domestic cats from the large city of Astana, Kazakhstan, collected in 2023-2024. Using nested PCR we identified 63 FcTTV-positive samples (30.6% prevalence), and the sequences were compared to global reference strains. Potential demographic associations (sex and age) were assessed. The study revealed an overall FcTTV prevalence of 30.6%. Infection rates showed no significant sex-related differences: ages varied 4-168 months. ORF1 sequencing revealed multiple FcTTV variants in 27% of samples, with no demographic links. Phylogenetic analysis revealed distinct patterns at both nucleotide and amino acid levels: 3 groups of nucleotide sequences (max divergence 21.68%; intra-cluster 5.15-6.8%), and 3 clusters of amino acid sequences (max divergence 16.81%; intra-cluster 2.82-6.68%). Deletions were found in ORF1 in some variants. Global phylogeny aligned clusters with Asian/European strains (90-98% identity), confirming FcTTV1 affiliation and inter-regional transmission. Our study of FcTTV in Kazakhstan reveals moderate virus prevalence with considerable genetic diversity across viral strains and frequent co-infections with multiple variants.