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HONG KONG — Eight more Americans from a quarantined cruise ship off Japan have been confirmed to have the new coronavirus, bringing the total number of U.S. citizens diagnosed on the vessel to 11, the operator said Friday.

One of them, Rebecca Frasure from Oregon, spoke to NBC News shortly after receiving her test results and as she waited to be airlifted to a Japanese hospital.

“Being alone in the hospital in a foreign country where people don’t speak my language, that’s definitely a concern,” she said by phone from her cabin on the Diamond Princess.

There are currently 12 diagnosed cases of the virus in the continental United States.

Princess Cruises announced 41 new cases of the virus on board the vessel Friday, of whom eight are Americans, bringing the total number of confirmed cases to 61. Most are Japanese citizens.

The 20 previous cases, including three Americans, were discovered in earlier batches of testing this week and the individuals were escorted off the ship. The vessel is quarantined off Yokohama, south of Tokyo, and has around 3,700 passengers and crew on board.

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Frasure, 35, said she was worried about heading to the hospital alone, as her husband, Kent, had tested negative and had to stay on the ship.

“They just told me that they will need to keep me in the hospital for at least three days for treatment, and then if I get better, then I will come back to the ship to finish up the quarantine in my cabin,” she said.

Frasure said she had been shocked to receive the positive test results, and did not remember coming into contact with anyone sick. Besides, she didn’t particularly feel unwell.

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The cruise ship Diamond Princess next to a bridge at Daikoku Pier in Yokohama, south of Tokyo, Japan on Friday. Kim Kyung-Hoon / Reuters

The global death toll from the coronavirus has risen to at least 638, compared to 565 two days ago, and confirmed cases have reached more than 31,000 on mainland China, compared to 28,000 Wednesday.

On board the ship, the alarm was raised after a former passenger tested positive.

Passengers on the Diamond Princess said they were first told they would have to stay in their rooms Wednesday, and that the crew had recently started bringing people out to the deck to get some fresh air and stretch their legs — prioritizing those without balconies.

Susan Archer from Marysville, Washington, said people had been quarantined to their rooms for 14 days and the reality of that was "starting to hit."

"It's kind of like a survivor show in a way," she said, adding that people had been really sanitary on the ship.

"I'm not worried at this point, but I don't like the solitary confinement," she said. "That is not a fun thing but I understand the necessity of it."

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Laundry, sheets and towels had not been changed, passengers said, but masks, gloves and thermometers had been distributed and passengers have been asked to regularly check their temperatures.

Dr. Mike Ryan, head of the World Health Organization's Health Emergencies Program, told a news briefing Friday that a lot of support was being provided to help passengers with their physical and mental health.

"It's a very stressful situation," he said.

Meanwhile, another cruise ship, World Dream, remained quarantined in Hong Kong. Three people who had been on board the ship during a previous voyage tested positive for the virus, the operator, Dream Cruises, said in a statement Thursday.

The company later added that no Americans were on board.

A third cruise operator, Holland America, said Thursday that one of its ships had been notified that it would not be permitted to call in Japanese ports. The Seattle-based operator denied anyone had the coronavirus on the ship, and said it was looking for a new port of disembarkation.

Princess Cruises said that unless there were further developments, the quarantine on the Diamond Princess should last until Feb. 19.

On board the ship, cabin fever is beginning to set in as the days tick by.

“We want off now and we want permission from the various countries to do so,” said Gay Courter, 75, who is from Crystal River, Florida.

“The government took people out of Wuhan, China, they can take us too."

Molly Hunter and Yuka Tachibana reported from Hong Kong; Arata Yamamoto reported from Tokyo, Japan; and Saphora Smith and Daisy Tennant-Thomas reported from London.