A person with the novel coronavirus was being treated Thursday at an unnamed San Francisco hospital, public health officials said.
The person being treated was brought to San Francisco from Travis Air Force Base in Fairfield after traveling there from a cruise ship, according to the San Francisco Department of Public Health.
The individual had no symptoms, but the person tested positive for the virus in Japan and was quarantined at the air force base.
Public health officials said all necessary precautions were being taken by the hospital to keep patients and staff safe.
Public health officials were not releasing the name of the hospital or the name of the patient to protect the patient's privacy.
A San Francisco hospital earlier this month treated two people from a different California county. The pair has since been discharged in good health and is no longer in the city, San Francisco officials said.
Public health officials said there is a low risk that a resident will get the virus. The risk depends on a person's travel history rather than culture, race or ethnicity.
Public health officials said no evidence exists of the virus spreading in the city.