Passenger tests aboard the Diamond Princess cruise ship in Japan confirmed at least 65 more cases of coronavirus on Monday, as some passengers took to social media to warn against depression over their confinement.
The figure takes the tally on board to 135, showing a rapid rise in the outbreak on the ship docked in the port of Yokohama.
Among the new 65 cases are 45 Japanese and 11 Americans, Japan's health ministry said.
"This is not news that anyone of us wanted to receive," the captain told passengers in a broadcast over speakers in their cabins. "However, we have been also advised since we are in the early quarantine period of 14 days; it was not unexpected."
The captain's remarks formed part of an audio recording posted on Twitter by Yardley Wong, a passenger documenting the experience on the ship, using the hashtag #anxiety.
Japan's health ministry confirmed the 65 new cases in a statement.
The Diamond Princess was placed in quarantine for two weeks upon arriving in Yokohama, south of Tokyo, on Feb. 3, after a man who disembarked in Hong Kong was diagnosed with the virus.
About 3,700 people are aboard the ship, which usually has a crew of 1,100 and a passenger capacity of 2,670. Passengers have been allowed on decks in shifts to get fresh air and encouraged to regularly take their temperature.
"Lots of the passengers now are getting a bit of cabin fever," British passenger David Able said in a video posted on Facebook. "Depression is starting to set in."
Another said he hoped assurances about the effectiveness of quarantine and ventilation on board would prove true.
"I will get nervous if we pass 200," said the 43-year-old Hong Kong resident quarantined on the boat with his wife, child and several of his family.
"Hoping best for those taken to hospital. At least two report back to us on Facebook that they are symptom-free," added the man, who declined to be identified.
Addressing some passengers concerned about the ventilation, the captain's latest announcement said that they are supplying "100 percent of fresh air" throughout guest rooms.
People who have been in close contact with newly confirmed cases on the ship face a longer quarantine than the originally planned period until Feb. 19, the World Health Organization said late on Sunday, without saying how many there were.
Japan's health ministry is recording infection counts on the ship and evacuee flights from China separately from the official tally. Domestic cases stand at 21.
Foreign Minister Toshimitsu Motegi said Japan would send a fifth chartered flight to China's central city of Wuhan, the epicentre of the virus outbreak, to bring citizens home.
The disease has killed 908 people, chiefly in mainland China, and infected more than 40,000.
The UK-flagged Diamond Princess is managed by Princess Cruise Lines, one of the world’s largest cruise lines and a unit of Carnival Corp.