A person in Northern California has contracted the coronavirus without traveling to regions hit by the outbreak or coming in contact with anyone known to have the infection, the first sign the disease may be spreading within a U.S. community, the Centers for Disease Control and Prevention reported Wednesday night.

How the person acquired the virus is unknown.

“It’s possible this could be an instance of community spread of covid-19, which would be the first time this has happened in the United States,” the CDC said in a statement, referring to the disease caused by the coronavirus. The health agency left open the possibility “that the patient may have been exposed to a returned traveler who was infected.”

The state of California, however, called the case its first instance of community transmission. The case was first reported by The Washington Post.

Community spread would represent a significant turn for the worse in the battle against the virus. To date, the United States has 60 known cases of the infection, with 59 among people who traveled to Asia or were close contacts of people who went there. The vast majority, 42, picked up the virus while quarantined on the Diamond Princess cruise ship off Japan.

If the infection is confirmed to be a case of “community spread,” said Jennifer Nuzzo, epidemiologist and senior scholar at the Johns Hopkins Center for Health Security, “it would confirm what we have long suspected — that there is a good chance there already are people infected in this country and that the virus is circulating undetected. It points to the need for expanded surveillance so we know how many more are out there and how to respond.”


The CDC said the case “was detected through the U.S. public health system — picked up by astute clinicians.” The agency said only that the person lived in California.

The individual is a resident of Solano County, according to the California Department of Public Health. The patient is being treated at UC Davis Medical Center.

Two officials from that hospital sent an email to employees Wednesday that said the patient arrived at the medical center Feb. 19 but was not tested until Sunday, despite an immediate request to the CDC.

The patient arrived from another hospital in Northern California, according to the email from David Lubarsky, vice chancellor of human health sciences, and Brad Simmons, the interim chief executive.

“When the patient arrived, the patient had already been intubated, was on a ventilator, and given droplet protection orders because of an undiagnosed and suspected viral condition,” they wrote. “Since the patient arrived with a suspected viral infection, our care teams have been taking the proper infection prevention (contact droplet) precautions during the patient’s stay.”

UC Davis asked the CDC to conduct a test for the virus because local and state labs were not doing so. “Since the patient did not fit the existing CDC criteria for covid-19, a test was not immediately administered. UC Davis Health does not control the testing process,” they wrote.


The CDC finally ordered a test Sunday and additional precautions were taken, they wrote. The agency confirmed the positive test Wednesday.

There are indications that other hospitals could be involved in the case. Kris Concepcion, fire chief and acting public information officer in Vacaville, Calif., said county officials had issued a directive not to transport any new patients to two local hospitals — NorthBay VacaValley Hospital in Vacaville and NorthBay Medical Center in nearby Fairfield. Concepcion declined to say why those orders had been given.

Steve Huddleston, vice president of public affairs at NorthBay Healthcare, declined to comment. He said the hospital was directing all inquiries to the California Department of Public Health.

The two hospitals are in Solano County, home to Travis Air Force Base, where hundreds of Americans repatriated from China and others brought home from the Diamond Princess cruise ship have been kept in quarantine. Many of them have been released.

The health department said it has already begun tracing people who may have come in contact with the coronavirus-infected individual.

“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 Sonia Angell, director of the California Department of Public Health and state public health officer.

The virus, which originated in Wuhan, China, has killed 2,801 people and sickened more than 82,000 as it has spread around the globe, reaching every continent except Antarctica. The CDC on Tuesday warned Americans that community spread is almost certain to occur, and to prepare for significant disruption in their daily lives.

President Trump on Wednesday evening appointed Vice President Pence as the new head of the task force coordinating the battle against the virus.

Faiz Siddiqui, Geoffrey A. Fowler and Nitasha Tiku in San Francisco contributed to this report.

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