Authorities in California on Friday identified a second case of coronavirus involving a patient who had not recently travelled overseas or had known contact with an infected person or traveller.
The identification of the case, in the state’s Santa Clara County, suggests the virus may be spreading in the US.
Dr Sara Cody, health officer for Santa Clara County, said “what we know now is that the virus is here present at some level”. She added: “What we still don’t know is to what degree.”
She said there was now the need for additional public health tools, on top of measures to quarantine individuals, trace contacts and restrict flights.
Santa Clara County sits in the heart of Silicon Valley, where a high concentration of technology companies are headquartered, including Apple and Alphabet. It is also home to Stanford University, located in Palo Alto.
Donald Trump, US president, on Thursday asked Mike Pence, vice-president, to lead Washington’s response to the health crisis, while downplaying the risk to Americans as “very low”.
The US Centers for Disease Control and Prevention said it had identified 62 cases of coronavirus in the US, including three people who had travelled from Wuhan, China, and 44 passengers on the Diamond Princess cruise ship from Japan.
On Wednesday, the CDC confirmed a reportedly novel case of coronavirus in Solano County between San Francisco and Sacramento, saying it was “possible” the virus had spread to the patient from an unknown source.
“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.
Some tech groups have already begun pulling back from domestic travel. Amazon told employees on Friday to defer any non-essential travel in or outside of the US and said it would withdraw from the Games Developer Conference scheduled in San Francisco next month, which organisers have since postponed. The YPO group, which is made up of chief executives and has about 28,000 members also cancelled its leadership summit in San Diego scheduled for next week.
London Breed, San Francisco mayor, called a state of emergency on Tuesday, seeking funds to prevent the spread of the virus if it reaches the city.
Santa Clara previously identified two cases of coronavirus in people who had travelled from mainland China. One patient had fully recovered as of last week, and the other patient was placed in isolation.