Monkeypox is a viral disease caused by infection with the monkeypox virus.  Monkeypox symptoms are similar to smallpox symptoms, but milder, and monkleypox is rarely fatal. Monkeypox was discovered in 1958 when two outbreaks of a pox-like disease occured 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) might harbor the virus and infect people.