The US has seen more than 1,800 cases so far, though that is thought to be an undercount as testing has also lagged.
There has been growing concern about the rate at which monkeypox is spreading - especially in New York City, epicentre of the US outbreak.
The disease, characterised by lesions on the skin, usually clears up on its own but can be extremely painful.
Most confirmed cases have been among men who have sex with men, although anyone can be infected with the virus.
