Family: Picornaviridae
Genus: Avisivirus
Distinguishing features
The genus is distinguished on the basis of genetic characters.
Virion
Morphology
No details are available on the morphology of virions.
Physicochemical and physical properties
Unknown.
Nucleic acid
Genome (Lau et al., 2014): c. 7,530 nt (5′-UTR: 548; ORF: 6,498–6,720; 3′-UTR: 264 nt). The 5′-UTR contains a type II IRES. The location of the cre has not been identified.
Genome organization and replication
Genome layout:
VPg+5′-UTRIRES-II-[1AB-1C-1D-(2A1npgp)/2A2npgp/2A3NTPase-2A4H-box/NC-2B-2C/3A-3B-3C-3D]-3′-UTR-poly(A)
The deduced polyprotein is of 2,165–2,239 amino acids. There is no L protein. The 1AB protein remains uncleaved. Avisiviruses have three to four 2A proteins, i.e. one or two short foot-and-mouth disease virus-like (2A1 and 2A2) with an NPG↓P motif, 2A3 with an AIG1-type guanine nucleotide-binding domain (GxxGxGKS NTP-binding motif) and 2A4 with an H-box/NC motif.
Biology
No virus has been isolated.Viral RNA was detected in faeces of turkeys (Meleagris gallopavo) and chickens (Gallus gallus domesticus) with gastrointestinal disease. Four types are distinguished by means of phylogenetic clustering (AsV-A1, AsV-B1, AsV-C1, -C2).
Derivation of names
Avisivirus-: from Avihepato sister-clade
Species demarcation criteria
Members of a species of the genus Avisivirus:
- share an essentially identical genome organization
- are less than 40% divergent in P1 aa sequence
- are less than 30% divergent in 2C + 3CD aa sequence
The divergence (number of differences per site between sequences) between members of different Avisivirus species ranges from 0.53–0.59 for P1 and 0.46–0.49 for 3CD.