The term “pox” originated from the English word “pock” (pustule), referring to skin lesions caused by a virus. This term was used for the nomenclature of viruses into families that cause pox lesions. A characteristic of poxviruses is the clinical manifestation of a “pox” lesion in the skin of infected animals. The classification of viruses into a genus is determined by the International Committee on Taxonomy of Viruses, which take into account many criteria including the type of disease they cause, host organisms, morphology, nucleic acid type and mode of replication. Members of each genus can be identified using serology as they often cross-react with each other. This is illustrated with the capripoxviruses, lumpy skin disease virus along with sheeppox virus and goatpox virus having no serotypes. The Poxviridae family consists of two subfamilies: the Chordopoxvirinae which infect vertebrates and the Entomopoxvirinae which infect insects. In the Chordopoxvirinae family, there are ten assigned genera and one unassigned genera (Table 6.1) (International Committee on Taxonomy of Viruses).