ins in the gene order of spike (S), envelope (E), membrane (M), and nucleocapsid (N) (5′–3′) (Fehr and Perlman, 2015). The large ORF 1ab is a replicase gene encoding polyproteins 1a (pp1a) and pp1b/1ab, which can be cleaved into 15–16 non-structural proteins (nsp2-nsp16 or nsp1-nsp16) by 3C-like proteinase (3CLpro, nsp5) and papain-like proteinase (PLpro, nsp3) (Bailey-Elki