Monkey pox is most commonly found in Africa and is caused by a virus belonging to the orthopoxvirus family. This virus is related to the virus that causes smallpox and variola virus which causes cowpox. It is believed to be originally from rodents, and the virus made the jump to humans in the remote rain forests of central and west Africa.
The first known major human outbreak of the virus occurred in 1996-1997 in the Democratic Republic of the Congo.