According to the CDC, monkeypox is a rare disease caused by infection with the monkeypox virus. Monkeypox virus is part of the same family of viruses as variola virus, the virus that causes smallpox. Monkeypox symptoms are similar to smallpox symptoms, but milder, and monkeypox is rarely fatal. Monkeypox is not related to chickenpox. Monkeypox was first discovered in 1958. The first human case of monkeypox was recorded in 1970.

Reference: About monkeypox