ICTV Virus Taxonomy Profile: Picornaviridae

Abstract

The family Picornaviridae comprises small non-enveloped viruses with RNA genomes of 6.7 to 10.1 kb, and contains >30 genera and >75 species. Most of the known picornaviruses infect mammals and birds, but some have also been detected in reptiles, amphibians and fish. Many picornaviruses are important human and veterinary pathogens and may cause diseases of the central nervous system, heart, liver, skin, gastrointestinal tract or upper respiratory tract. Most picornaviruses are transmitted by the faecal-oral or respiratory routes. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the taxonomy of the Picornaviridae, which is available at www.ictv.global/report/picornaviridae.

Keywords: ICTV; Picornaviridae; enterovirus; foot-and-mouth disease virus; poliovirus; rhinovirus; taxonomy.

Fig. 1.

Surface view of the poliovirus 1 (Enterovirus C) virion (1HXS). Reproduced from VIPERdb (http://viperdb.scripps.edu) [7].

Fig. 2.

Genome organization and expression of enteroviruses and aphthoviruses. Viral RNA (vRNA) is polyadenylated and covalently linked to a virus-encoded protein (3B) at its 5′ end. Cleavages facilitated by 2A^pro of the enteroviruses (black arrow) or by an NPG↓P motif at the C-terminus of 2A of foot-and-mouth disease virus (white arrow) release the P1 and P1-2A proteins, respectively. The leader proteinase L^pro releases itself from the polyprotein by cleavage at its own C-terminus. P2 and P3 polypeptides are precursors of the nonstructural proteins necessary for genome replication. Further polyprotein processing is mediated by 3C^pro (cleavage sites indicated by arrow heads). Processing of 1AB, the precursor of 1A and 1B, is thought to be autocatalytic and occurs in empty capsids or at virion maturation (white diamond).