It’s not clear whether the second case is linked to the state’s first confirmed case, which was identified last week in Oakland County, spokeswoman Lynn Sutfin told the Detroit Free Press.
Both remain under investigation, Sutfin said.
Health officials are trying to identify close contacts of the people who have monkeypox and might have been exposed, she said.
"Right now, the information we have suggests that the number of high- and intermediate-risk contacts associated with the two identified cases is small," Sutfin said.
Michigan is one of 34 U.S. states with known cases of the virus.
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Monkeypox belongs to the same virus family as smallpox, but its symptoms are milder. People usually recover within two to four weeks without needing to be hospitalized, but the disease occasionally is deadly.