Human monkeypox is a rare viral zoonotic disease caused by Monkeypox virus of the genus Orthopoxvirus. It occurs mostly in the rain forests of central and western Africa. Human monkeypox has a clinical presentation similar to that of smallpox, including characteristic rash. Lymphadenopathy is not a common feature of smallpox and is therefore a key distinguishing feature of monkeypox. By contrast with smallpox, human monkeypox has low transmissibility between human beings.
Many animals are infected with monkeypox virus under natural conditions, including squirrels, non-human primates, and rats. However, the primary reservoir for human infection remains unknown.
