Distinguishing features

The genus is distinguished on the basis of genetic characters. 

Virion

Morphology

No details are available on the morphology of the virions. 

Nucleic acid

Genome (Du et al., 2016, Phan et al., 2011, Lim et al., 2014, Lau et al., 2016): c. 8,931 nt (5′-UTR: 504-721 nt; ORF: 7,410-7,449 nt; 3′-UTR: 712-946 nt). 5′-UTR harbours a type II IRES. 3′-UTR is the longest of picornaviruses. The location of the cre has not been identified.

Genome organization and replication

Genome layout:

VPg+5′-UTR^IRES-II-[1A-1B-1C-1D-2A^H-box/NC/2B-2C/3A-3B-3C-3D]-3′-UTR-poly(A)

The deduced polyprotein is of 2,468-2,491 aa. 2A has a H-box/NC motif. 

Antigenicity

See discussion under family description.

Biology

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)]. Available sequence data suggest 8 types.

 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.

Rosavirus A and Rosavirus B both include two genetic types, while Rosavirus C includes four genetic types. 

Member species

Virus names, the choice of exemplar isolates, and virus abbreviations, are not official ICTV designations.

Derivation of names

Rosa-: from rodent stool-associated