Page last reviewed: May 1, 2023
Mpox is a rare disease caused by infection with the mpox virus. Mpox virus belongs to the Orthopoxvirus genus in the family Poxviridae. The Orthopoxvirus genus also includes variola virus (which causes smallpox), vaccinia virus (used in the smallpox vaccine), and cowpox virus. Mpox is not related to chickenpox.
Mpox was first discovered in 1958 when two outbreaks of a pox-like disease occurred in colonies of monkeys kept for research. Despite being named “monkeypox”, the source of the disease remains unknown. However, African rodents and non-human primates (like monkeys) may harbor the virus and infect people.
The first human case of mpox was recorded in 1970. Since then, mpox has been reported in people in several other central and western African countries. Prior to the 2022 outbreak, nearly all monkeypox cases in people outside of Africa were linked to international travel to countries where the disease commonly occurs, or through imported animals.