The genus is distinguished on the basis of genetic characters.
No details are available on the morphology of virions.
Genome (Phan et al., 2011, Lim et al., 2014, Du et al., 2016, Lau et al., 2016): c. 8,931 nt (5′-UTR: 504–721 nt; ORF: 7,410–7,449 nt; 3′-UTR: 712–946 nt). The 5′-UTR harbours a type II IRES. The 3′-UTR is the longest of picornaviruses. The location of the cre has not been identified.
Genome organization and replication
The deduced polyprotein is of 2,468–2,491 aa. 2A has an H-box/NC motif.
No virus has been isolated. Viral RNA was detected in faecal samples of humans and rodents [canyon mouse (Peromyscus crinitus), brown rat (Rattus norvegicus), black rat (R. rattus), Sikkim rat (R. andamanensis), chestnut white-bellied rat (Niviventer fulvescens)]. Eight genetic types are distinguished by means of phylogenetic analysis (Rosavirus A: 2 types; Rosavirus B: 2 types; Rosavirus C: 4 types).
Derivation of names
Rosavirus: from rodent stool-associated virus
Species demarcation criteria
Members of a species of genus Rosavirus:
- share a common genome organization
- are less than 30% divergent in the polyprotein aa sequence
- are less than 30% divergent in the P1 aa sequence
- are less than 25% divergent in the 2C + 3CD aa sequence