The US' newest coronavirus patient had no known exposure to anyone sick and hadn't gone to China, which suggests containment might be impossible

A patient in Solano County, California, has gotten the COVID-19 coronavirus without traveling to China or having any known contact with someone sick, the Centers for Disease Control and Prevention confirmed on Wednesday.

"This person appears to be a community-acquired case of coronavirus, which would be the first here in the United States," Bela Matyas, the Solano County health officer, said in a press conference on Thursday. He added, however, that he doesn't think this is the only such case.

"There are probably cases of coronavirus from community acquisition in multiple parts of the country right now," Matyas said.

That means the virus is likely spreading undetected in the US, according to Amesh Adalja, an infectious-disease expert at the Johns Hopkins Center for Health Security.

Adalja offered a simple definition of community spread:

"'Community spread' reflects the fact that the virus is out there in the community spreading from person to person, meaning that it's not just spreading from people who had contact with someone from China or a travel history, but that it's something established in the community," he said.

That reality, Matyas said, means health officials have to transition "from trying to contain the disease to more of a mitigation approach."

A delay in detection

The California patientis now in serious condition, according to CNN .

She initially went to the NorthBay VacaValley Hospital on February 15. The 50-bed hospital is in Solano County, which is also home to the Travis Air Force Base, where some Americans evacuated from China and from the quarantined Diamond Princess cruise ship have been quarantined .

A surgeon at the base, who requested that he be kept anonymous, told Business Insider that it's likely the new case has some connection to the the base, given the proximity.

But Matyas said no such link has been found and added that workers on the base were "scary meticulous" about safety.

"This individual has no connection whatsoever to that federal mission and to any of the personnel that have been involved in that evacuation process," he said.

travis air force base Hector Amezcua/AP Photo

The patient was not tested for COVID-19 at VacaValley during her four days there. After her symptoms worsened, she was transferred to the University of California, Davis Medical Center in Sacramento on February 19. But she wasn't tested there either until four days later.

"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," the center said in a statement.

Until now, the CDC has made decisions about whether to test people for the coronavirus based on whether they have recently traveled to places with outbreaks.

But this case, Adalja said, shows that "when we have protocols set up to really identify patients only based on travel history, those are going to fall short of identifying all cases."

Matyas said testing criteria are indeed changing now, and the CDC praised the doctors who diagnosed the woman in a statement on Thursday.

"This case was detected through the US public health system picked up by astute clinicians," the CDC said.

Dozens of healthcare workers were exposed

coronavirus california AP Photo/Damian Dovarganes

Health officials are working to trace and isolate anyone the patient had contact with her family has been quarantined, and hospital staff are being evaluated and tested.

Aimee Brewer, president of NorthBay Healthcare, said any medical workers who had direct contact with the patient at VacaValley have been tested for the virus and are now on paid leave at home. So far, there have been no more positive tests, she said.

"As far as the headcount is concerned, at this time I can say it's a moving target," Steve Huddleston, vice president of public affairs at NorthBay Healthcare, said in a press conference Thursday. "We have identified dozens of employees on our health team, but it still remains less than 100."

According to CNN , a University of California, Davis student is also under investigation, and the student's two roommates are being isolated at their home off campus as well.

The CDC said in a statement on Thursday that "unprecedented, aggressive efforts have been taken to contain the spread and mitigate the impact of this virus."

A question of when, not if

A day before this case of community spread was reported, CDC officials suggested it was imminent.

"It's not so much a question of if this will happen anymore, but rather more a question of exactly when this will happen and how many people in this country will have severe illness," Dr. Nancy Messonnier, the head of the National Center for Immunization and Respiratory Diseases at the CDC, said during a media briefing.

But thus far, the US lags behind other countries in testing as of Wednesday, only 445 Americans had been tested for the virus.

The ultrastructural morphology exhibited by the 2019 Novel Coronavirus (2019-nCoV), which was identified as the cause of an outbreak of respiratory illness first detected in Wuhan, China, is seen in an illustration released by the Centers for Disease Control and Prevention (CDC) in Atlanta, January 29, 2020. Alissa Eckert, MS; Dan Higgins, MAM/CDC/Handout via REUTERS Reuters

"At first, CDC was the only place where testing could be performed," Richard Martinello, an associate professor of infectious disease at the Yale School of Medicine, previously told Business Insider . "For a country of our size, when you only have a single site doing that, it limits the resources available for testing."

The CDC sent test kits nationwide earlier this month, but those were also found to be flawed, so only about a dozen labs can currently run the tests, according to The Washington Post .

The cats out of the bag in terms of it having spread

Solano County and the nearby San Francisco and Santa Clara counties have all declared emergencies.

Matyas said the declaration frees up resources to "allow us to investigate this incident more effectively and more efficiently."

But he added that containment is "only possible when you're dealing with a disease condition where you know everyone who's sick, and they get sick before they spread, and you can contain them and that's a rare reality."

Coronavirus face mask Manuel Silvestri/Reuters

Now, he said, efforts must focus on mitigation because "we know the cat's out of the bag in terms of it having spread, and what we're trying to do is slow the spread as much as possible."

California Gov. Gavin Newsom announced Thursday that 33 people in the state have tested positive for the virus including citizens repatriated to military bases and 8,400 people are being monitored. He stressed that the risk to the public is still low, but added that the state needs access to more resources.

"We have just a few hundred testing kit,s and that's surveillance testing as well as diagnostic testing. That's simply inadequate to do justice to the kind of testing that is required to address this issue head on," Newsom said.

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