The new coronavirus strain that originated in the Chinese city of Wuhan has crossed the Pacific, with U.S. health authorities confirming the first case of the virus in the country on Tuesday.
A man in Washington State first experienced symptoms after returning from a trip to a region near Wuhan.
He was hospitalized last week with pneumonia, but was later confirmed to have the Wuhan coronavirus.
The virus has already spread beyond China's borders to South Korea, Thailand, Taiwan and Japan, but it is the first time it has appeared outside Asia.
Suspected cases are also popping up in other parts of the world, including the Philippines, Hong Kong, and Australia.
And the situation is fast spreading across China, with more than 3-hundred people infected and six dead as of Wednesday.
Among them are people who have not been to Wuhan, meaning that they've contracted the virus indirectly from others.
With the situation developing into an international emergency, experts are trying to find the source of the virus, and many are pointing to the illegal exotic animals sold at the fish market in Wuhan where the virus was first detected.
Jeremy Farrar, a specialist in infectious disease epidemics said the virus may have been lurking in animals for decades before adapting to infect humans.
The so-called 'wet markets' in Wuhan illegally sell wild animals, including rodents, bats and raccoons for local delicacies.
And he says, those who touch infected animals are exposed to such viruses.
The SARS virus outbreak in 2002 came from a raccoon-like animal from China's Guangdong Province. That outbreak led to a ban on the sale of exotic animals.
Many experts also say that the upcoming Lunar New Year holiday is a critical milestone in the outbreak's development as millions of Chinese are set to travel overseas during that time.
Faced with such urgency, the World Health Organization is set to hold an emergency meeting on Wednesday to discuss whether to classify the situation as an international emergency.
Lee Kyung-eun, Arirang News.