A virologist looking at an electron microscope image of a MERS coronavirus, a close relative of the novel coronavirus. Photo: Arne Dedert/picture alliance via Getty Images
A person in California who hadn't traveled to a country impacted by the novel coronavirus nor had any known contact with anyone infected by the virus has tested positive to COVID-19, the CDC said in a statement.
Why it matters: Per the CDC, "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. Community spread means spread of an illness for which the source of infection is unknown." However, the patient may have "been exposed to a returned traveler who was infected," the CDC noted. "At this time, the patient's exposure is unknown," it said.