Molecular evolution and characterization of novel Seneca Valley virus (SVV) strains in South China.

Seneca Valley virus (SVV) is an emerging swine virus associated with porcine vesicular disease. From June to the end of 2017, five SVV strains were isolated from the swine herds in Guangdong, China. Complete genomic sequences of these newly discovered SVV strains were analyzed by genomic and phylogenetic analysis. The results revealed that these SVV strains could be grouped into five genetic branches together with most of other Chinese strains. Interestingly, it is for the first time that a stretch of 11-nucleotide insertion was found in the 5' UTR region of SVV GD04/2017 strain. Additionally, phylogenetic analysis based on the ORF and VP1 genes showed that the SVV GD06/2017 strain is significantly distinct from all previous Chinese SVV strains. Furthermore, the five SVV strains displayed similar growth kinetics in the ST-R cell line, while the SVV GD04/2017 and GD06/2017 strains presented relatively slower rates than the GD01/2017 and GD03/2017 strains. The findings of this study indicate the emergence of novel SVV strains in China, which would increase the knowledge about SVV genetic diversity and reinforce the importance of SVV surveillance.