Health officials have detected the first case of infection with the new coronavirus spreading in China, in the United States.
The SARS-like virus first became apparent in Wuhan, Hubei Province, China, and it has now begun spreading across China, with around 300 confirmed cases and six deaths from the virus. Other countries began reporting cases of the pneumonia-related virus, that has been confirmed to be spreading by human-to-human contact.

The first confirmed case in the United States is a man from Washington state in his 30s, after he returned from a trip to Wuhan on Jan. 15. He suffered no symptoms at the time, but when he became ill he reported to authorities after reading online about the outbreak in Wuhan, reported The New York Times.

He sought treatment four days later and now is in isolation at Providence Regional Medical Center in Everett, Washington.

Wuhan has 11 million inhabitants and is a busy transportation hub, millions of people are expected to pass through there over the next few weeks, as the Chinese New Year or Spring Festival holiday is celebrated. From Jan. 10 until Feb. 18, Chinese celebrate Chinese New Year, and this year travel will be even more congested, as it coincides with university students’ winter holiday break.

An estimated 20 percent of workers in China’s cities come from rural areas, and the 40 days of celebrating the New Year is the one time they are able to make it back home. Trains, buses, ferries, planes, and roads will be packed with people eagerly heading homeward for the celebrations.

It is a time of the year when around 400 million Chinese travel across China, as well as millions set to go abroad to visit families. It has been described as the world’s largest annual human migration in previous years.

The coronavirus, named 2019-nCoV, has also claimed victims in Japan, Thailand, and South Korea, Taiwan, and now the United States. Australia also has a suspected case, tests are not yet confirmed on a Queensland man who returned home from Wuhan and became ill, but has recovered, although still quarantined at home.

Several airports worldwide, including JFK in New York, SFO in San Francisco and LAX in Los Angeles will screen passengers returning from infected regions.

At a press conference on Tuesday afternoon, the CDC said that it’s expanding the screenings to include Chicago’s O’Hare and Atlanta’s Hartsfield-Jackson international airports and that any passengers originating from Wuhan into the United States will be funneled to one of the five airports with screening, even if this requires rebooking them on different flights, reports  NPR.

“Cars may be randomly tested in case wild animals, a potential source for the virus, are transported, and tour groups are prohibited from leaving the city,” NPR’s Amy Cheng reported from Beijing.

The new coronavirus will also be eager to find new victims to infect, and the New Year holiday could create the perfect storm.