Chordopoxviruses

Chordopoxviruses are a subfamily of the Poxviridae family that infect vertebrates. They are large, enveloped, brick-shaped double-stranded DNA viruses with linear genomes that typically range from about 150 to 350 kilobase pairs and encode hundreds of genes. Replication occurs in cytoplasmic viral factories, with the virus providing much of the transcription and replication machinery.

The subfamily comprises numerous genera, including Orthopoxvirus (variola, vaccinia, cowpox, monkeypox), Parapoxvirus (Orf virus, pseudocowpox virus, bovine papular stomatitis virus), Avipoxvirus (fowlpox, canarypox, pigeonpox), Capripoxvirus (sheeppox, goatpox, lumpy skin disease virus), Leporipoxvirus (myxoma virus, Shope fibroma virus), Suipoxvirus (swinepox), Yatapoxvirus (tanapox virus, yaba monkey tumor virus), and Molluscipoxvirus (Molluscum contagiosum virus).

Hosts span many vertebrates; diseases range from localized skin lesions to systemic illness. In humans, Orthopoxviruses include variola (the eradicated smallpox) and vaccinia, while monkeypox presents as an emerging zoonosis. In animals, poxvirus infections affect livestock, wildlife, and birds, with Avipoxvirus causing canarypox and fowlpox in birds. Transmission routes vary by virus but often involve close contact or respiratory spread.

The genome carries many immune-modulating and host-range genes that influence tissue tropism and virulence. Poxviruses replicate entirely in the cytoplasm and assemble mature virions through a conserved morphogenesis pathway. Because of their size and stability, chordopoxviruses have been developed as vaccine vectors and as model systems in virology. ICTV maintains their taxonomy with updates as new data arise.