The first case in the U.S. of a more severe strain of mpox was reported in San Mateo County, the California Department of Public Health said.

The unidentified patient had recently returned from Africa, where the virus has caused a deadly epidemic, health officials said.

The United States’ first known case of a more severe strain of mpox was confirmed in California, the US Centers for Disease Control and Prevention said Saturday. The risk of clade I mpox to the public remains low,