Health officials in Washington state say they have detected a suspected Monkeypox case in a man who recently returned from travelling overseas.
Officials in King County, which covers Seattle, are working to identify who the man has been in contact with while he was infectious, and are contacting people they described as being “potential low risk exposures”.
They say the man did not require hospitalisation and is isolating at home, they said.
Washington is the fifth US state to report a confirmed or suspected case of the Monkeypox virus.
Testing carried out at the Washington State Public Health Laboratory showed the man had tested positive to the family of viruses known as orthopoxviral.
Further testing will be carried out by the Centers for Disease Control and Prevention.
There has been one confirmed case of Monkeypox in the United States in a Massachusetts man.
Suspected cases have also been reported in Utah, Florida and New York.
World Health Organisation (WHO) official David Heymann said on Monday the leading theory on how the current outbreak is being spread was sexual contact among gay and bisexual men who attended two recent raves in Spain and Belgium.