The number of confirmed coronavirus cases contracted in Contra Costa County grew by a half dozen over the past two days, with the county’s health department on Thursday saying 16 people had tested positive for Covid-19.

None of those 16 patients have died, according to health officials. A 17th case is being treated in the county, but that person contracted the disease in another jurisdiction, health officials said.

On Wednesday, the county announced that it had confirmed 10 cases, and that six of them had picked up the virus from unknown contacts within the community. Two of them contracted the virus on the Grand Princess cruise ship that went from San Francisco to Mexico, and two got it from someone they knew who had it.

Health officials did not say immediately where the additional six cases originated.

The county declared a local emergency Tuesday, allowing it to mobilize resources and receive reimbursement money from the state and federal governments.