Purpose To understand the porcine teschovirus (PTV) infection and the molecular evolution characteristics of prevalence strains in Yunnan Province, thus lay foundation to the prevention and control of this disease in pig farms.
Methods Fecal samples were randomly collected from pig farms in Qujing, Mile and Dali in Yunnan Province, and the partial gene fragment of PTV 5′-UTR was amplified, cloned and sequenced by RT-PCR. Homology analyzed by using bioinformatics software and a phylogenetic tree was constructed.
Results The positive rate of PTV in collected samples was 27.3% (32/117). After sequences comparing, repeated sequences were removed and six prevalence strain sequences finally achieved. Homology analysis results showed 93.2%-98.9% nucleotide identity between strains, and 89.7%-100.0% with selected reference sequence. The phylogenetic tree showed that YNDL-2 and YNDL-3 strains were closely related to the PTV strains isolated in Sichuan Province; YNQJ-1 was closely related to Japanese strain; YNDL-1, YNQJ-4 and YNQJ-5 clustered together and were closely related to the isolated strain in the Dominican Republic. It was indicated that there were different serotypes infection in the same pig farm.
Conclusion PTV is highly prevalence in Yunnan pig farm, and great evolutionary relationship differences found in detected strains. In the same pig farm, there are at least two genotypes co-infection, and no obviously regional feature is found. Results lay a foundation for further study of pathogenesis, vaccine development and effective control of PTV.
DownLoad: