SACRAMENTO, Calif. >> A new coronavirus case in California could be the first in the U.S. that has no known connection to travel abroad or another known case, a possible sign the virus is spreading in a U.S. community, health officials said.

California officials said the person is a resident of Solano County, northeast of San Francisco, and is getting medical care in Sacramento County. They said they have begun the process of tracking down people who the patient has been in contact with, a process known as contact tracing.

The patient was brought to UC Davis Medical Center from another Northern California hospital on Feb. 19 but it was four days before the CDC heeded a request to test the patient for COVID-19, according to an email sent to employees Wednesday by the hospital’s interim CEO, Brad Simmons, and David Lubarsky, CEO of UC Davis Health.

The patient arrived on a ventilator and special protection orders were issued “because of an undiagnosed and suspected viral condition,” according to the email sent to employees.

The hospital asked the CDC to test for the coronavirus but testing was delayed until Sunday “since the patient did not fit the existing CDC criteria for COVID-19,” the email said.

Solano County health officials said in a statement today they are working with local, state and federal officials to identify people who may have been exposed to person infected in the county.

“While this is considered a serious public health threat, the risk to Solano County residents and the general public is low at this time,” the county health department said.

UC Davis, which has treated other coronavirus patients, has been taking infection prevention precautions since the patient arrived. The email said officials believe there was a small chance that others at the facility were exposed to the virus.

“Nevertheless, a small number of medical center employees have been asked to stay home and monitor their temperatures,” the email said.

The CDC had not responded today to email messages sent Wednesday night seeking comment.

All of the 59 other cases in the U.S. had traveled from abroad or had been in close contact with those who traveled. Health officials have been on high alert for so-called community spread.

Earlier U.S. cases included 14 in people who traveled back from outbreak areas in China, or their spouses; three people who were evacuated from the central China city of Wuhan; and 42 American passengers on the Diamond Princess cruise ship who were evacuated by the federal government to the U.S. from where the ship was docked in Japan.

Some of those evacuated were taken to Travis Air Force Base, which is in Solano County. A number of the earlier cases have been in California, including some of the people taken to Travis and one in which a traveler who returned to San Benito County south of San Francisco and spread it to a spouse.

California officials have been preparing for the possibility that community spread of the virus might first surface in the state.

“We have been anticipating the potential for such a case in the U.S., and given our close familial, social and business relationships with China, it is not unexpected that the first case in the U.S. would be in California,” said Dr. Sonia Angell, Director of the California Department of Public Health and State Public Health Officer, in a statement.

The outbreak, which began in China, has infected tens of thousands of people in more than three dozen countries, with the vast majority in mainland China.

The new virus is a member of the coronavirus family that can cause colds or more serious illnesses such as SARS and MERS.

The virus can cause fever, coughing, wheezing and pneumonia. Health officials think it spreads mainly from droplets when an infected person coughs or sneezes, similar to how the flu spreads.

Officials are advising people to take steps to avoid infection with coronavirus or other respiratory infections like colds or the flu, including washing hands with soap and water and avoiding close contact with people who are sick.