Washington State, USA - A person in Washington State is infected with a new respiratory virus. The outbreak began at a market in China and now has spread to at least four other countries.

The patient, who was hospitalized with pneumonia last week, had recently traveled to Wuhan, China, where the outbreak appears to have originated, federal officials have found.

Investigators tested samples from the patient for the presence of the virus; positive results were received over the weekend. Officials declined to identify the patient, who was said to be quite ill.

News of the first case in the United States comes amid growing evidence that the virus spreads from person to person, although it is not clear how easily.

The outbreak, which began in a seafood and poultry market in Wuhan, a city of 11 million, is spreading: Patients have been identified in Beijing, Shanghai and Shenzhen, as well as Taiwan, Japan, Thailand and South Korea.

On Tuesday, Chinese authorities confirmed that six people have died of the infection in Wuhan. Nearly 300 cases have been reported to date in China. Many of the patients lived in or traveled to Wuhan.

The World Health Organization will meet tomorrow to decide whether to declare the outbreak an international public health emergency. But information about the new virus is still thin, and it’s not clear whether or how many Americans are at risk.