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 (Holtz et al., 2008, Kapoor et al., 2008a, Blinkova et al., 2009, Cotten et al., 2014, Kapusinszky et al., 2012): c. 7,632–7,802 nt (5′-UTR: up to 1,361 nt; ORF: 6,366–6,402 nt; 3′-UTR: 75–93 nt). The location of the cre has not been identified.

Genome organization and replication

Genome layout:

VPg+5′-UTR^IRES-II-[1A-1B-1C-1D-2A1^npgp/2B-2C/3A-3B-3C-3D]-3′-UTR-poly(A)

The deduced polyproteins are of 2,113–2,133 amino acids. There is no L protein. 2A is a short foot-and-mouth disease virus-like polypeptide (NPG¯P). Sequence data (e.g., JN867757, KM516909) suggest interspecies recombination (Kapusinszky et al., 2012).

Antigenicity

See discussion under family description.

Biology

Known natural hosts are humans and pigs. Viral RNA was detected in faeces and pharyngeal swabs of diseased and clinically healthy humans and pigs.

Species demarcation criteria

Members of a species of the genus Cosavirus:

• are less than 35% divergent in P1 aa sequence,
• are less than 10% divergent in 2C + 3CD aa sequence,
• share a common genome organization.

The divergence (number of differences per site between sequences) of different cosavirus species ranges from 0.4–0.53 for P1 and 0.22–0.37 for 3CD.

Sequence data of capsid protein-encoding gene regions indicate at least 35 types within these species (CoSV-A1 to -A25, CoS-V-B1, tentative CoSV-C1, CoSV-D1 to -D5, CoSV-E1, -E2, CoSV-F1).

Member species

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

Establishment of Cosavirus C is pending due to incomplete virus sequences.

Derivation of names

Cosa-: from common stool-associated

Related, unclassified viruses

Virus names and virus abbreviations are not official ICTV designations.