UPDATE Jan. 21, 2:20 p.m.: A person traveling from Wuhan to Washington state was reportedly infected with the new coronavirus and is now receiving treatment at a hospital in Everett.

Cases of a mysterious and deadly new strain of coronavirus are rapidly climbing in China, where officials now say it’s possible for the pneumonia-like illness to be contracted through human-to-human transmission.

Besides in China, cases have been recorded in Japan, Thailand, Taiwan, and South Korea — mostly from travelers coming back from Wuhan. Potential cases are also being monitored in the Philippines and Australia, also due to Wuhan travelers. China’s central Hubei province, home to Wuhan, has recorded the bulk of China’s 300 cases, according to the Washington Post, and it’s believed the cases are somehow connected to a now-closed seafood market. The World Health Organization said human-to-human transmission is “limited,” with the primary source likely being an animal.

As of Tuesday, six people had died from the virus, which had not previously been seen in humans, according to NBC News. The virus is of the coronavirus family, which includes deadly diseases like Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS), but can also cause the sort of cold-like symptoms that retreat after simple, over-the-counter treatments. It’s the still-fresh memory of SARS — which infected more than 8,000 people and killed nearly 800 across Asia in 2002 and 2003 — that’s prompted great anxiety about this new virus.

Experts with the World Health Organization will meet in Geneva on Wednesday to determine how the outbreak can be properly managed, according to USA Today. In the U.S., the Centers for Disease Control and Prevention said it would increase screenings on travelers at certain airports in California and New York. Authorities across Asia are responding by increasing screening at common places of travel, like airports and highways.

“The lesson we’ve learned is coronavirus infections are serious and one of the newest and biggest global health threats,” Peter Hotez, a vaccine scientist at Baylor College of Medicine in Houston, told CNN.

Cover: Women wear face masks as they walk down a street in Hangzhou in eastern China’s Zhejiang province, Tuesday, Jan. 21, 2020.(Chinatopix via AP)