New York CNN Business  — 

Cruise stocks fell Thursday amid revelations that 7,000 people are being held on a cruise in Italy after a passenger showed symptoms of the Wuhan coronavirus.

Shares of Norwegian Cruise Line Holdings, Royal Caribbean Cruises and Carnival Corporation tumbled in morning trading in New York, at times sliding as much as 5%.

The drop came as two Italian media outlets reported a woman and her husband from Hong Kong were each being kept in solitary confinement in the hospital section of an unidentified Costa Cruises ship. The cruiseliner, a Carnival subsidiary, plans to keep the remaining passengers and crew aboard the ship until the couple tests negative for the infection.

A spokesperson for Costa Cruises told CNN that a 54-year-old woman aboard the ship had a fever, a symptom of the virus.

“All the other passengers are, at the moment, remaining on board,” the spokesperson said.

The coronavirus, which originated in the Chinese city of Wuhan in Hubei Province, has killed 170 people as of Thursday morning and there are 7,800 diagnosed worldwide.

China’s government put travel restrictions in certain places across the country in an attempt to contain the virus. More than 60 million people are affected.

In a Jan. 28 securities filing, Carnival (CCL) said these measures led it to suspend operations from Chinese ports from Jan. 25 to Feb. 4, resulting in nine cruise line cancellations. The company also said the restrictions could cause Chinese clients to cancel bookings for cruises that sail from outside of China.

Fallout from the coronavirus could cut earnings by $0.03 to $0.04 per share, Carnival said, and by $0.05 to $0.06 if the restrictions extend until the end of February. The Miami-based firm had expected to deploy 5% of its global capacity in China in fiscal year 2020.

Meanwhile, Royal Caribbean (RCL) said it has canceled three sailings until Feb. 8, saying this would have an impact on its 2020 financial results of about $0.10 per share, and double that if travel restrictions remain in place until the end of February.

A spokesperson for Norwegian (NCLH) said the company wasn’t changing its itineraries and that it was checking the temperature of all passengers boarding in Hong Kong. Anyone with a fever of 100.4°F or higher will not be allowed to board, nor will any guests who visited mainland China in the last 30 days.

The coronavirus has caused the closures of stores owned by Starbucks, Ikea and McDonald’s in certain areas of China. British Airways, United Airlines, American Airlines and a host of other global carriers have either stopped flying there or said they would cut back on the number of flights.

On Monday, the U.S. Centers for Disease Control and Prevention issued a level 3 warning, its highest-degree alert, telling travelers to avoid non-essential travel to China. The agency also said the immediate health risk to the American public remained low.