SAN FRANCISCO - China has put one of its largest cities Wuhan on quarantine, an unprecedented act that comes out of concern for the new coronavirus outbreak which now has confirmed cases in at least five other countries.
So far, there have been at least 17 deaths and nearly 600 patients confirmed to have the new coronavirus.
Some passengers arriving at SFO from Hong Kong and mainland China were wearing masks, worried about the increasing spread of the new coronavirus.
"Most people were wearing masks...on the streets and in the airport, on the plane," said Catherine Yang, a Chinese tourist from Shenzen who arrived with her family at SFO from the Hong Kong airport. She says stores in their hometown were selling out of masks.
Health officials worry the coronavirus outbreak could get worse...Coming just before china's busiest travel season with the lunar new year this weekend.
"A lot of my friends are in China and they're all wearing all the masks because they're working everywhere and they're trying to going back home for the spring festival," said Curtis Sun, a tour guide from Los Angeles who was waiting at SFO for his group to arrive from Hong Kong.
Some Chinese researchers estimate thousands more people could be infected by the virus that was traced to a market in the Central China City Of Wuhan.
That prompted a complete lockdown on all air and train travel in and out of Wuhan a city of some 11 million people with business ties to the U.S. Companies such as General Motors ordered employees to stay away.
At SFO, China Southern Airlines canceled its direct flights from Wuhan Thursday due to the quarantine.
It is unclear how they will impact health screenings conducted by the Centers for Disease Control at SFO, LAX, New York's JFK as well as Atlanta and Chicago airports.
"We haven't heard anything different from the CDC so our understanding is that they're still planning to conduct screenings which makes sense because there probably will be a residual trickle of activity coming from Wuhan," said SFO Airport spokesman Doug Yakel.
A map showing the spread of the Wuhan coronavirus was posted online by researchers at Johns Hopkins University. It shows where cases have now been confirmed in Thailand, Taiwan, South Korea, Japan and the United States.
Doctors in Washington state said the only U.S. patient, a man in his thirties who had traveled to Wuhan, is being monitored at a hospital.
"Patient continues to rest comfortably, appears in no distress," said Dr..Jay Cook of Providence Regional Medical Center.
The World Health Organization met Wednesday and plans to follow up Thursday, as they decide whether to declare a global health emergency.
"Our team is on the ground in China as we speak working with local experts and officials to investigate the outbreak and get more information," said Tedros Adhanom Ghebreyesus, the World Health Organization Director-General.
Symptoms for the new coronavirus are similar to a common cold.