Illustration of a man with a rash caused by infection with a pox virus (family Poxviridae) and a close-up of one such virus particle. Four genera of Poxviridae can infect humans: Orthopoxvirus, Parapoxvirus, Yatapoxvirus and Molluscipoxvirus. These genera contain prevalent viruses such as Mpox, smallpox (now eradicated bar laboratory populations) and vaccinia virus.