The Epidemiology Of Torque-teno Canis Virusat One Suburb In Shanghai And Analysis Of The Complete Genome

In the present study, 199 sera samples of dogs were collected at suburbs in Shanghai in 2010 spring (from March to May) to detect the prevalence of Torque-Teno canis virus uing nested PCR. The results showed that 29 out of 199 samples (14.6%) were positive for TTV. The infection rate in area H is highest (7/16), and is signicantly defferent from others(p<0.01). Comparing to mini dogs, medium dogs (such as shepherds) may be more sensitive to TTV (p<0.1); Comparing with positive prevalence between the sexes, the positive ratio of female dogs was 20.1%, while the ratio of males was 11.0%, after T test , we found that the two ratios have significant difference(p = 0.059).After that, we designed two sets (4 pairs) nest primers to amplify the whole genome of one isolate in this study designated Sh-TTV203. Compring with the reported Torque teno canis virus genome sequences, the ORFs,promoters,CpG islands and polyA structures of Sh-TTV203 were analysed, and the fairly reliable ORFs were predicted.The ORF I protein, which contains higher diversity, was translated for further study. Physicochemical property,hydrophobic regions,transmembrane and signal of ORF I protein have been studied. With analysis of DNA sequece, ORF I protein was predicted as a capsid protein of Torque teno canis virus, which may have relation with the virus pathogenicity and play the role of making host cell membrane and virus capsid fused. Furthmore, we searched motifs,domains and epitopes in specific database, the results showed that ORF I protein belongs to Viral_ssRNA_CP family, and some putative B cell epitopes also have been found.At last, the phylogeny trees were constructed based on the genome of Sh-TTV203 with 5 prototype of genome sequences of human TTV,non-human primates TTV,TTMV,sea turtle tomovirus,tupaia TTV,torque teno susi virus,torque teno canis virus and torque teno felis virus, using neighbor-joining,maximum parsimony,maximum likelihood method by PHYLIP 3.68 program. The phylogeny trees showed that torque teno canis virus is closest with torque teno susi virus I, torque teno felis virus and sea lion anellovirus. Torque teno susi virus II is far from group I, locates between tupaia TTV and torque teno douroucouli virus, which suggests there might be two parallel evolution, or some inter-species transmiting had happened. Human TTV are closesd to Japaness macaque TTV and non-human TTMV.