Orthopoxvirus is a genus of viruses in the family Poxviridae and subfamily Chordopoxvirinae. Vertebrates, including mammals and humans, and arthropods serve as natural hosts. Currently, 13 species are in this genus, including the type species Vaccinia virus. Diseases associated with this genus include smallpox, cowpox, horsepox, camelpox, and monkeypox. The most infamous member of the genus is Variola virus, which causes smallpox. It was eradicated globally by 1977, through the use of Vaccinia virus as a vaccine. The most recently described species is the Alaskapox virus, first isolated in 2015.