Subfamily: Chordopoxvirinae

Genus: Centapoxvirus

Distinguishing features

The genus Centapoxvirus includes the species Yokapox virus (exemplar isolate yokapox virus [YKPV]) and Murmansk microtuspox virus (exemplar isolate Murmansk poxvirus [MMPV]). YKPV was isolated from a pool of mosquitoes collected in the Central African Republic, but despite being isolated from insects, is not an entomopoxvirus. In infection experiments, YKPV caused 100% mortality in neonatal mice inoculated intracerebrally, although the definitive host is still unknown. In contrast, Murmansk poxvirus was isolated in the forest tundra of Russia from a root vole (Microtus oeconomus). Taken together it is thought that the natural hosts of the centapoxviruses are therefore likely to be rodents. In vitro, centapoxviruses can be cultured in a number of cell lines. There is no evidence to date of YKPV or MMPV being zoonotic, but a third related, unclassified virus (NY_014), has been isolated from a human renal transplant patient.

Virion

The virions are typical of other poxviruses, ovoid and with a dumbbell-shaped core. They measure approximately 150 x 250 nm. Nothing is known about the ether-sensitivity of infection. Despite being apparently most similar to the orthopoxviruses, no serological cross-reactivity was reported with vaccinia virus or variola virus.

Genome organization and replication

The dsDNA genome ranges from approximately 175 kbp (YKPV) to 204 kbp (MMPV), encoding approximately 186 or 206 genes; the G + C content is 25–30% (Zhao et al., 2011, Smithson et al., 2017). The central genomic region contains those genes that encode proteins, as with the other chordopoxviruses, primarily involved with DNA and RNA metabolism, replication and virus morphogenesis. This region is colinear with the that of orthopoxviruses and in pairwise comparisons Yokapox virus is more similar to the orthopoxviruses than any of the other genera. Centapoxviruses are however distinct from members of all other poxvirus genera, having at least 3 genes unique within the Chordopoxviridae, including an apparent orthologue of ornithine decarboxylase.

For replication please see discussion under family description.

Species demarcation criteria

The general chordopoxvirus classification criteria of <98% nucleotide identity across the central core of the genome is used to delineate species, whereas >98% identity would indicate separate strains of the same species.

Related, unclassified viruses

Virus names and virus abbreviations are not official ICTV designations.