Chordopoxvirinae

Poxviruses
Virus classification
Group: Group I (dsDNA)
Order: Unassigned
Family: Poxviridae
Subfamily: Chordopoxvirinae
Genera

Avipoxvirus
Capripoxvirus
Cervidpoxvirus
Crocodylipoxvirus
Leporipoxvirus
Molluscipoxvirus
Orthopoxvirus
Parapoxvirus
Suipoxvirus
Yatapoxvirus

Chordopoxvirinae is a subfamily of the Pox viruses. Species in this subfamily infect vertebrates.

Four genera in this subfamily contain species that infect humans: molluscipox, orthopox, parapox and yatapox.

Virology

The virions are generally enveloped though the intracellular mature virion form of the virus, which contains a different envelope, is also infectious. They vary in their shape depending upon the species but are generally shaped like a brick or as an oval form similar to a rounded brick because they are wrapped by the endoplasmic reticulum. The virion is exceptionally large, its size is around 200 nm in diameter and 300 nm in length and carries its genome in a single, linear, double-stranded segment of DNA.[1]

Taxonomy

The classification in this subfamily is based on the morphology, nucleic acid type, mode of replication, host organisms and the type of disease caused.

Nine genera in this subfamily are recognised. There are also a number of species that have not yet been assigned to a genus.

The species in the genus Avipoxvirus infect birds; those in the genera Caiman poxvirus and Crocodylipoxvirus both infect crocidylians.

The other genera in this subfamily infect mammals.

Genera

Evolution

The last common ancestor of the extant poxviruses that infect vertebrates existed 0.5 million years ago. The genus Avipoxvirus diverged from the ancestor 249 ± 69 thousand years ago. The ancestor of the genus Orthopoxvirus was next to diverge from the other clades at 0.3 million years ago. A second estimate of this divergence time places this event at 166 ± 43,000 years ago.[2] The division of the Orthopox into the extant species occurred ~14,000 years ago. The genus Leporipoxvirus diverged ~137 ± 35,000 years ago. This was followed by the ancestor of the genus Yatapoxvirus. The last common ancestor of the Capripoxvirus and Suipoxvirus diverged 111 ± 29,000 years ago.

A Bayesian study of Orthopox genomes suggests that the unclassified Yoka poxvirus diverged from the lineage that gave rise to the orthopoxviruses ~90,000 years ago.[3] The orthopox viruses diverged from the other pox viruses about 10,000 yeara ago. Camelpox, taterapox and variola viruses arose 3,500 years ago and horsepox virus ~3,000. These viruses may have arise in these viruses first emerged in the region of the Horn of Africa.

Another Bayesian study suggests that variola arose ~3500 years ago.[4]

References

  1. ↑ International Committee on Taxonomy of Viruses (2004-06-15). "ICTVdb Descriptions: 58. Poxviridae". Retrieved 2005-02-26.
  2. ↑ Babkin IV, Babkina IN (2011) Molecular dating in the evolution of vertebrate poxviruses. Intervirology 54(5):253-260. doi:10.1159/000320964.
  3. ↑ Babkin IV, Babkina IN (2012) A retrospective study of the orthopoxvirus molecular evolution. Infect Genet Evol
  4. ↑ Babkin IV, Shelkunov SN (2008) Molecular evolution of poxviruses. Genetika 44(8):1029-1044

External links