Subfamily: Chordopoxvirinae

Genus: Oryzopoxvirus

Distinguishing features

The Oryzopoxvirus genus includes the single species, Cotia virus, members of which were isolated from sentinel mice during an arbovirus surveillance programme in Sao Paulo, Brazil in 1961. Oryzopoxviruses were re-isolated at a nearby site in São Paulo during the continuation of the arbovirus surveillance program in 1962 but were designated at the time as Embu SPAn880 virus. Genome sequencing in 2014 revealed that Embu virus is a member of the species Cotia virus (Ibrahim et al., 2014). Members of the species Cotia virus are presumed to be transmitted by arthropods taking a blood meal or mechanically on mouth parts. Oryzopoxviruses have a relatively broad host range in vitro and can be passaged in neo-natal mice, but their natural host remains obscure. There is considerable serological cross-reactivity with members of the species Vaccinia virus (genus Orthopoxvirus), Myxoma virus (genus Leporipoxvirus) and Swinepox virus (genus Suipoxvirus), but no cross-neutralising activity. There is no evidence that members of the species Cotia virus are zoonotic.

Virion

The virion is brick-shaped with a size and morphology typical of orthopoxviruses including a dumbbell-shaped core. Nothing is known about ether-sensitivity of infection.

Genome organization and replication

The dsDNA genome (approximately 185kbp) putatively encodes 185 genes; the G + C content is approximately 24%. The inverted terminal repeats (ITRs) at either end of the genome are relatively large (approximately 14 kbp); 15 genes are duplicated at each end of the genome. This could be as a result of extensive passaging in cell culture prior to the virus sequence being determined. The central core of the genome is co-linear with that of other poxviruses with the 90 genes found to be conserved in the majority of other chordopoxviruses also being present. In pairwise comparisons, the predicted amino acid sequences of these 90 gene products bear greatest similarity to those of the Capripoxvirus, Suipoxvirus, Yatapoxvirus, Leporipoxvirus and Cervidpoxvirus (CSYLC) genera, but Cotia virus formed a distinct branch of its own within this grouping. In terms of gene content, the genome regions at either end, outwith the conserved central core, bear greater similarity to those of orthopoxviruses than to those of viruses of the CSYLC clade, including encoding three genes that are predominantly found in the orthopoxviruses and not at all within the CSYLC clade. Cotia virus also encodes at least three proteins that appear to be unique within members of the subfamily Chordopoxvirinae, namely two C-C chemokine-like proteins and a novel MHC-1 like protein distinct from those found in molluscum contagiosum virus and squirrelpox virus (Afonso et al., 2012).

For replication please see discussion under family description.

Species demarcation criteria

There is only one species in the genus and therefore criteria have not been agreed.

Related, unclassified viruses

Virus names and virus abbreviations are not official ICTV designations.