The Centers for Disease Control and Prevention issued a 14-day mandatory quarantine order Friday for the roughly 200 passengers who were flown to March Air Reserve Base from Wuhan, China, where the deadly coronavirus was first detected.
Here's what to know about the coronavirus
The group of 195 passengers, who arrived on a U.S. State Department-chartered airplane on Wednesday, had been staying at the military base under a three-day voluntary isolation while they were evaluated to ensure none developed any symptoms. Public health officials said the passengers would be able to return home following the 72 hours.
But on Thursday, Riverside County's public health officer ordered one of the passengers to be quarantined for the virus' two-week incubation period "or until otherwise cleared'' after that person tried to leave the base.
In issuing the federal quarantine order for the entire group, which is mostly made up of diplomats and their families, CDC officials pointed to a case reported in Germany in which a person might have spread the virus to another person before developing symptoms.
They also mentioned a report published Thursday night in the New England Journal of Medicine showing that infected people can transmit the virus before they develop symptoms.
The plane from China first landed in Anchorage, Alaska, for a refueling stop and preliminary screening of passengers was conducted by CDC personnel about 10:30 p.m. Tuesday. Passengers were also monitored throughout the flight and none of them were deemed high risk, Rear Admiral Dr. Nancy Knight, director of the Division of Global Health Protection at the CDC, said.
The flight was originally scheduled to land at Ontario International Airport, but the CDC announced the new landing site for the aircraft Tuesday night.
The plane touched down at March ARB at 8:11 a.m Wednesday.
The original flight manifest stated that there were 240 passengers aboard the flight, but officials said some people did not show up or did not have the proper documentation to board. One person had a fever and had to stay behind in China.
Among the passengers were nine children, the youngest of which is 1 month old.
CDC said that although little is known about the coronavirus, the risk of infection for people in the United States is low.
While we realize that many people are nervous right now, understand that we are committed to your safety and are taking all precautions to ensure both the passengers and our residents are safe,'' County Supervisor Jeff Hewitt said.
The coronavirus outbreak was first detected in December in the industrial city of Wuhan in the Hubei province of central China. Since then, more than 9,800 cases have been reported in China, with at least 213 deaths, and the virus has been confirmed in patients in a handful of other nations, including the United States. As of Thursday, six cases have been confirmed in the United States -- including one in Los Angeles County and one in Orange County.
The CDC on Thursday morning confirmed the first person-to-person infection in the United States, involving a husband and wife in Chicago.
The World Health Organization declared the outbreak an international public health emergency.
The Riverside County Emergency Management Department set up a dedicated phone line to answer residents' questions about coronavirus at 951-358-5134.