Isolation, Identification and Genetic Evolution Analysis of New Epidemic Strains of Senecavirus A in Guangdong Province

【Objective】 The pathogen of blistering disease with nasal and coronet in two swine farms in Guangdong province was detected, and new strains of Senecavirus A (SVA) were obtained, which provided materials for subsequent research. 【Method】 RT-PCR and real-time RT-PCR were used to screen the clinical samples. The clinical samples were isolated, treated and cultured with ST cells and BHK-21 cells. The virus was purified by sucrose density gradient centrifugation method and observed by electron microscopy. The specific primers of SVA were designed to amplify the cell supernatant, and sequenced for sequence analysis. The TCID50 of the virus isolated was determined. 【Results】 The swinery were diagnosed as SVA by RT-PCR and real-time RT-PCR. It was found that the cultured cells had CPE from the 6th generation. The virion observed by electron microscopy was about 25 nm. The amplified sequences were submitted to the NCBI Blastn, which were identified as SVA. The TCID50 result of the strain SVA CH-GDBL1-2016 was 106.8 and the TCID50 result of the strain SVA CH-GDBL2-2016 was 106.7.【Conclusion】 The strains SVA CH-GDBL1-2016 and SVA CH-GDBL2-2016 provide a material basis for the subsequent diagnosis and vaccine development of Senecavirus disease.