3 | RESULTS
Via RT-PCR test, SVV RNA was positive in those collected samples, and the genome was subsequently amplified. The buffalo-origin SVV was termed, SVA/GD/China/2018 (GenBank Accession No. MN615881). The virus was purified using the double agarose mulching method and cultured it stably in BHK-21 and NA cells, PK-15 and ST cells, Vero and Marc-145, MDBK cells propagated to 30 passages, MDCK cells were only propagated to three passages (Appendix Figure).
The sequence analysis showed that the genome similarity of SVA/GD/China/2018 was 93.4%–99.1%, and the polyprotein similarity was 97.5%–99.4% compared with the other 35 SVV strains (Table 2). Interestingly, SVA/GD/China/2018 shared the highest nucleotide similarity with the wild boar strain, Sichuan HS-01 (99.1%), and the highest polyprotein similarity with the KS15-01-like strain (99.4%). Genetic evolutionary analysis revealed that SVA/GD/China/2018 clustered in the same branch with Sichuan HS-01 from Sichuan, China (Figure 1).
Compared with the published SVV sequences, SVA/GD/China/2018 was found to have seven unique amino acid mutations (Figure 2) as follows:440A (Alanine) – V (Valine), 497E (Glutamic acid) – K (Lysine), and 511A (Alanine) – V (Valine) at the VP3 protein; 1119V (Valine) – I (Isoleucine) at the 2C protein; 1430A (Alanine) – V (Valine) at the 3A protein; 1710H (Histidine) – Y (Tyrosine) at the 3C protein; and 1854V (Valine) – I (Isoleucine) at the 3D protein.