In 2003, the virus entered the United States with African rodents, and these in turn infected prairie dogs sold as pets. Dozens of people in the country were infected with monkeypox in that outbreak. Monkeypox is a rare disease caused by infection with monkeypox virus. The monkeypox virus belongs to the genus Orthopoxvirus of the Poxviridae family.
The genus Orthopoxvirus also includes variola virus (which causes smallpox), vaccinia virus (used in smallpox vaccine), and bovine pox virus. Monkeypox spreads when someone comes into close contact with another person, animal, or material infected with the virus. The virus spreads through close contact with people, animals, or materials infected with the virus. It enters the body through broken skin, airways, eyes, nose and mouth.
Although person-to-person transmission is also thought to occur through respiratory droplets, that method requires prolonged face-to-face contact because droplets cannot travel more than a few feet, according to the CDC.