UPDATE, Saturday, 4:02 p.m.: A fourth case of novel coronavirus has been confirmed in Santa Clara County, according to a report.

This latest case is related to a previous one reported Friday. In the earlier case, a woman, 65, with chronic health conditions was hospitalized for a respiratory illness. The latest patient is an adult woman who is a "household contact" of the 65-year-old woman, according to health officials with the Santa Clara County Public Health Department.

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Health officials said Friday that a new coronavirus case of unknown origin has been identified in Santa Clara County.

This marks the second case of community transmission of COVID-19 in the United States and California, as the patient has no history of traveling to a country with an outbreak, and hasn't had contact with a traveler or infected person.

“This new case indicates that there is evidence of community transmission, but the extent is still not clear,” Dr. Sara Cody, the health officer for Santa Clara County, said in a statement. “I understand this may be concerning to hear, but this is what we have been preparing for. Now we need to start taking additional actions to slow down the spread of the disease.”

The patient is a 65-year-old woman with chronic health conditions and was hospitalized for a respiratory illness.

The woman was hospitalized with a respiratory illness and the county conducted the test to diagnose the virus. Health officials there are tracking down anyone the woman might have met and infected.

Due to privacy conditions, more details on the patient aren't being released.

This is the third person in the county who has tested positive. The other two had traveled to Wuhan, China, the epicenter of the virus.

MORE: Are elderly at greater risk for complications with coronavirus?

A statement from the Santa Clara County Health Department advised the public to wash their hands, avoid touching their faces, stay away from people who are sick and start thinking about family preparedness, including "how to take care of sick family while not getting infected."

The release also said schools should plan for "absenteeism and explore options for tele-learning, and enhance surface cleaning," while businesses should plan for telecommuting options.

This is a developing story.

Amy Graff is a digital editor at SFGATE. Email her: agraff@sfgate.com.

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