A sailor at Naval Base San Diego tested “presumptive positive” for the newest strain of coronavirus, the first believed case for a sailor in California.

Pentagon officials told Navy Times that the he is quarantined at home off the base.

The sailor is assigned to one of the 220 tenant commands. There is no indication that a warship’s crew is affected.

“Presumptive positive” tests are those that reveal the presence of COVID-19 but which have not been certified by the Centers for Disease Control and Prevention.

Military medical providers are conducting a contact investigation to find who has been in close contact with the service member and possibly exposed. Those identified so far have been notified and told to isolate themselves in their residences and monitor for symptoms of the disease.

Officials say that Naval Base San Diego is coordinating with county, state and federal health authorities to protect both military personnel and the local population.

“The health and well-being of our sailors, our civilian employees and their families is important to the Navy and we urge everyone to continue to follow CDC health guidelines as this situation continues,” said Navy Region Southwest spokesman Brian O’Rourke.

Although known for the warships that line its piers, Naval Base San Diego is also a major training site. Training Support Center San Diego, for example, is the central hub of support for Naval Education and Training Command efforts across the entire Pacific Rim, including instruction for surface warfare, submarine, security force, naval aviation and information warfare students.

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As of Friday morning, the California Department of Health was tracking 247 positive cases of coronavirus across the state, including five deaths. That tally doesn’t include passengers from the Grand Princess cruise ship docked in Oakland.

On Friday, San Diego Unified officials announced that schools will close on Monday to help prevent the spread of Covid-19, and will reopen April 6th, unless conditions call for an extension.

This is a breaking story and Navy Times is communicating with officials at the Pentagon and in San Diego. We will continue to update.