“…The families Arteriviridae, Coronaviridae and Roniviridae make up the order Nidovirales. The arterivirus genome is a polycistronic, single-stranded RNA of positive polarity with a 5 type I cap (Sagripanti et al, 1986), and a 3 poly(A) tract (Brinton et al, 1986;Contag et al, 1986;Sagripanti, 1985;van Berlo et al, 1982). Arterivirus genomes range in length from 12.7 to 15.7 kb with SHFV being the longest (accession numbers: EAV, NC002532; LDV, NC002534; PRRSV, NC001961; SHFV, NC003092).…”