Mpox (monkeypox).

Mpox, a zoonotic orthopoxvirus, originally identified in 1958, exhibits two distinct genetic strains or clades, clades 1 and 2. Before 2022, mpox was predominantly isolated in the endemic regions of West and Central Africa. Sporadic outbreaks of travel-associated clade 2 mpox had previously occurred in nonendemic areas, but persistent human-to-human transmission within nonendemic regions had not been documented until recently.