(CNN) — Coronavirus has been confirmed in Southern California — making it the third case in the United States — as a top Chinese health official delivered some worrisome news about efforts to contain the fast-moving virus.
The Centers for Disease Control and Prevention notified Orange County health officials Saturday that a potential case of coronavirus tested positive.
The person who tested positive traveled from Wuhan, China — the epicenter of the outbreak — and is in isolation and in “good condition” at a local hospital, the Orange County Health Care Agency said in a statement.
State and federal officials are following up with anyone who may have had close contact with the person and is at risk of infection.
News of the latest American case comes as Chinese Health Minister Ma Xiaowei delivered the revelation that people can spread the virus before they have symptoms — which a veteran US health adviser called a “game-changer,” but not in a good way.
It calls into question current US practices to contain the virus, Dr. William Schaffner, a longtime adviser to the Centers for Disease Control and Prevention, said.
“When I heard this, I thought, ‘Oh dear, this is worse than we anticipated.’ It means the infection is much more contagious than we originally thought,” said Schaffner, an infectious disease expert at Vanderbilt University Medical Center.
If Ma is correct — and information about this virus is constantly evolving — people can go two weeks without realizing they’re sick, during which time they can spread the virus, which has killed more than 50 people in China.
In addition to California, cases have been reported in Illinois and Washington state. The Illinois woman had not been sick while traveling from Wuhan to the US on January 13, said Dr. Jennifer Layden, an epidemiologist with the Illinois Department of Health, on Friday.
The CDC said it’s taking aggressive measures to stop the spread of the virus in the United States, but while it considers it a serious public health threat, the immediate risk to Americans is low.
At least 56 people have been killed by the coronavirus in China, nearly 2,000 confirmed cases have been reported as the nation struggles to contain the outbreak.
Chinese authorities have imposed indefinite restrictions on public transport and travel, with motor vehicles banned in Wuhan’s city center starting Sunday to control the flow of people. Only vehicles with special permits, free shuttles and government vehicles will be allowed to move around.
Amid the lockdown, countries like the US and France have been trying to evacuate their citizens from the central Chinese city. Outside of China, more than 40 confirmed cases have been identified in about a dozen countries.
Coronaviruses are transmitted by animals and people, and the Wuhan strain has been linked to a market in the city that was selling seafood and live animals, including wild species. The Chinese government announced Sunday that is banning all sales of wild animals throughout the country
Beijing will deploy an additional 1,600 medical professionals to Wuhan to help the city cope with the growing number of coronavirus patients, health officials said.