Page last reviewed: September 22, 2022
Monkeypox is a rare disease caused by infection with the monkeypox virus. Monkeypox 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. Monkeypox is not related to chickenpox.
Monkeypox 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 monkeypox was recorded in 1970. Since then, monkeypox 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.