Orthopoxviruses—plagues of mankind, strategists in immune evasion, teachers in vaccination

Abstract

Smallpox, the mankind’s greatest plagues caused by Variola virus (VARV), is officially eradicated since 1979. The reason for this success was the clear picture of the disease, the compulsory immunization worldwide with the Vaccinia virus (VACV), but essentially the fact that VARV is not zoonotic and has no reservoir in the environment. VARV belongs to the subfamily Chordopoxvirinae of the family Poxviridae and is classified in the genus Orthopoxvirus (OPXV). OPXVs are closely related and cross-protective to each other after infection of their hosts. Zoonotic OPXVs pathogenic for humans are Vaccinia virus (VACV), Buffalopox virus (BPXV), Cowpox virus (CPXV), Monkeypox virus (MPXV), and Camelpox virus (CMLV).