Positive test results have come back for a fourth San Luis Obispo County Jail inmate.
The sheriff's office says the inmate was immediately isolated away from other inmates after becoming symptomatic on Tuesday.
The positive test result came back Wednesday.
"All inmates in the exposed housing units are being tested and are being monitored for symptoms," the sheriff's said in a press release.
The first positive cases among inmates at the jail were reported over the weekend.
Three correctional deputies and one patrol deputy with the sheriff's office have also tested positive.
All are said to be recovering and there have been no hospitalizations linked to cases at the jail, officials say.