Why are monkeypox cases suddenly emerging across the world and could the virus have mutated?

Monkeypox, which was first identified in 1970, usually only occurs outside central and western African when an infected traveller returns home.
Photograph: Dado Ruvić/Reuters

The sudden emergence of monkeypox in several countries has raised questions about how the virus, which is most common in central and west Africa, has managed to spread.

Many health experts have said the monkeypox cases in 12 countries are not cause for panic, given the virus is much less infectious than illnesses like Covid and rarely fatal, but it is highly unusual.