Orthopox : variola virus , vaccinia virus , cowpox virus , monkeypox virus , smallpox ( eradicated ) ; Parapox : orf virus , pseudocowpox , bovine papular stomatitis virus ; Yatapox : tanapox virus , yaba monkey tumor virus ; Molluscipox : molluscum contagiosum virus ( MCV ) . Orthopox : smallpox virus ( variola ) , vaccinia virus , cowpox virus , monkeypox virus ; Parapox : orf virus , pseudocowpox , bovine papular stomatitis virus ; Yatapox : tanapox virus , yaba monkey tumor virus ; Molluscipox : molluscum contagiosum virus ( MCV ) .