As of Wednesday, the nine cases have been confirmed in Massachusetts, Florida, Utah, Washington, California, Virginia and New York, the US Centers for Disease Control and Prevention (CDC) told reporters.
Most of the infections detected worldwide so far have not been serious. Many, but not all, have been reported in men who have sex with men. Symptoms include fever and a distinctive bumpy rash.
All of the US cases “are in gay, bisexual and other men who have sex with men,” CDC director Rochelle Walensky said in a press briefing. Ms Walensky advocated an approach “guided by science, not stigma”.
More than 20 countries where monkeypox is not endemic have reported outbreaks of the virus, with around 200 confirmed infections and more than 100 suspected cases, mainly in Europe. The World Health Organization has urged countries to step up surveillance for monkeypox.
The first case of monkeypox in the United States was reported in Massachusetts last week.
Some of the nine cases identified as of Wednesday have recent international travel history to areas with active monkeypox outbreaks, but “some do not,” the CDC director said Thursday.
The disease, which occurs mainly in West and Central Africa, is a viral infection that was first recorded in the Democratic Republic of Congo in the 1970s.
“We shouldn’t be surprised to see more cases reported in the United States in the coming days,” Raj Panjabi, White House senior director for health security and biodefense, said at the press briefing.