Abstract:

A blister-like disease was found on a pig farm which was immunized against foot-and-mouth disease in Henan province, it was suspected infected with Seneca virus type A. The purpose of this study was to isolate, identify the virus and analyze its genetic evolution. The samples' nucleic acid tested positive by RT-PCR and FQ-PCR were inoculated into BHK-21 cells and cultured by passage. The virus was identified by indirect immunofluorescence assay, electron microscope observation, whole genome sequence and evolutionary analysis. The results indicate that the strain was SVA, which was named HeNXX/swine/2017; electron microscopy showed that the virion was a typical icosahedron with a diameter of about 30nm; this SVA strain has a high breeding efficiency in BHK-21 cells, the highest virus titer was 10^9.5 TCID₅₀·mL^-1; the total genome length is 7 288 bp (without PolyA), and it has the highest homology with 2 USA strains. A strain of SVA was successfully isolated in this study, which will provide further study basis for the related disease.

Key words: Senecavirus A, isolation, identification, genetic evolution analysis