Travel industry leaders are closely monitoring the rapidly spreading coronavirus outbreak believed to have begun in Wuhan, China, for its potential impact on international travel.

Hundreds of cases of the new strain of coronavirus have been detected around China, including heavily populated Hong Kong and Macao, and in other countries, including Japan, South Korea, Thailand, Singapore, Vietnam and, as of last week, one report in the United States.

U.S. health officials confirmed person-to-person spread of the virus is occurring although it’s unclear how easily the virus spreads among people. Severe illness, including illness resulting in a number of deaths in China, has been reported, while other patients have had milder illness and been discharged. Symptoms associated with the virus include fever, cough and trouble breathing. The first U.S. coronavirus patient, who arrived from Wuhan to Washington state this month, was treated for a mild case of the infection.

The U.S. Travel Association has been in contact with authorities at the Centers for Disease Control and Prevention (CDC), which has currently labeled this as a “Level 2: Practice Enhanced Precautions” health event. Travelers are being encouraged to follow guidance issued by the CDC. U.S. health officials are requiring travelers from Wuhan to undergo screening at Chicago’s O’Hare International Airport, New York’s JFK International Airport, Atlanta’s Hartfield-Jackson International Airport, Los Angeles International Airport and San Francisco International Airport.

Major Chinese cities, including the capital of Beijing, have banned all large gatherings over the coming Lunar New Year festival, a massive holiday on the Chinese calendar that begins on Friday, in an effort to contain the outbreak.