Hong Kong CNN  — 

The Westerdam cruise ship was supposed to have been the lucky one.

After being stuck at sea for days, when Japan, the Philippines and Thailand turned it away over concerns it had passengers who could have been infected with the novel coronavirus, on Friday, the Southeast Asian nation of Cambodia finally allowed the Westerdam to dock.

Passengers met with Cambodian Prime Minister, Hun Sen, as they left the ship. The cruise operator said no cases of the virus had been found on board.

The situation contrasted sharply with the ongoing crisis on board the Diamond Princess, which was found to have hundreds of infected passengers while in quarantine off the coast of Yokohama in Japan.

US President Donald Trump even thanked Cambodia for allowing the cruise ship to dock, due to the 650 Americans on board.

Then came the bad news.

On Saturday, one of its passengers tested positive for the coronavirus during a stopover in Malaysia.

The 83-year-old American woman had been on the first charter flight taking 143 Westerdam passengers to Malaysia, from where they could fly home.

Now questions are being raised over how the woman was infected, and whether authorities will be retesting the other 2,257 passengers and crew, about half of whom who have already left the ship.

What we know about the patient

When the American woman arrived in Malaysia, she only had a cough.

She had no fever or difficulty breathing, but told authorities she felt unwell. A chest X-ray conducted by the Malaysian Ministry of Health confirmed she had signs of pneumonia. After subsequent tests, she was diagnosed with the coronavirus. She is in a stable condition.

All other Holland America charter flights to Malaysia for the remaining Westerdam passengers have been canceled.

“All Westerdam cruise ship passengers still remaining in Cambodia will not be allowed entry into Malaysia, taking into account that they are close contacts with a confirmed (coronavirus) case,” the Malaysian government said in a statement Monday.

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Singapore tightens rules for entry from China
03:54 - Source: CNN

The Thai government also announced Monday that it would no longer be accepting any Westerdam passengers until February 28.

Where did she get the virus?

The novel coronavirus, known as Covid-19, has spread rapidly around the world after an outbreak in the Chinese city of Wuhan late last year. It has now infected more than 73,000 people, leading to 1,873 deaths.

It isn’t clear from official statements where the American woman contracted the virus or how long she has had it.

The Westerdam left Singapore on January 16 for what was supposed to be a 30-day trip around Asia. The ship visited Thailand, Cambodia and Vietnam, according to marinetraffic.com. But after departing Hong Kong on February 1, where 768 guests joined the boat, that it quickly became unwelcome in ports around the region.

When the boat reached Cambodia, it had 1,455 passengers on board, including 650 Americans, 271 Canadians, 127 British people, 91 Dutch people, 79 Australians, 57 Germans and 30 people from mainland China and Hong Kong.

Westerdam representatives said the company had checked that no one on board the ship had traveled to mainland China in the 14 days prior to the cruise. They also said that all guests will receive a refund of their cruise fare, plus a cruise credit worth 100% of what they paid for this trip.

In a statement, the Holland America Line, which operates the Westerdam, confirmed the virus case but was insistent that everyone on the ship had been screened on February 10, five days before the positive diagnosis.

“No individual was identified with an elevated temperature. Also, during disembarkation in Cambodia guests underwent an additional health screening including the completion of a written health questionnaire,” the company said in a statement Sunday.

The Diamond Princess cruise ship is seen anchored at the Daikoku Pier Cruise Terminal in Yokohama port on February 13, 2020. - At least 218 people on board a cruise ship quarantined off Japan have tested positive for the novel COVID-19 coronavirus, authorities said February 13 as they announced plans to move some elderly passengers off the ship. (Photo by Kazuhiro NOGI / AFP) (Photo by KAZUHIRO NOGI/AFP via Getty Images)
Man describes why he refused to evacuate quarantined ship
10:55 - Source: CNN

But given the woman had no fever when she arrived in Malaysia it is unclear how many other passengers could also be infected and asymptomatic.

What will happen to the other passengers?

The 1,000 passengers and crew who remained on the ship in Cambodia on Sunday have now been tested by the local government. Holland America said Monday that the test results would take “several days.”

However, there are still 600 passengers in the Cambodian capital of Phnom Penh, according to the Cambodian Ministry of Health, and they are now all being tested in their hotels. An initial batch of 406 results came back negative, Holland America said in a statement posted online.

“Guests at a hotel in Phnom Penh have all completed the Covid-19 screening. Results are being returned when completed, with the first batch of 406 all being negative. Cleared guests may travel home, and arrangements are being made for those guests,” said the statement.

It is not clear what restrictions those remaining passengers who have yet to be tested are under, or whether they are subject to additional quarantine measures in the capital.

Of the 143 passengers who traveled to Malaysia on the infected woman’s flight, six were held for further testing. The rest were allowed to continue their journeys.

The locations of about 500 other passengers are currently unknown, with many believed to have already left Southeast Asia.

CNN’s Isaac Yee, Mick Krever and Eric Cheung contributed to this article.