Hong Kong - The fast-spreading coronavirus outbreak has upended dream vacations for thousands of sea-faring passengers.

The 2,257 passengers and crew abroad MS Westerdam heaved a sigh of relief when they finally saw land from their cabin windows and were able to set foot in Sihanoukville, Cambodia. Their cruise liner had been marooned for days after five countries denied it entry, fearing that somebody on board the ship may be infected.

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On Friday, the passengers were welcomed by Cambodian Prime Minister Hun Sen, who handed out flowers to welcome them.

Though no one has shown any symptoms of the coronavirus, the Westerdam's crew and passengers went through a health screening at the port.

Cambodia's Prime Minister Hun Sen welcomes the passengers and crew of MS Westerdam on Friday in Sihanoukville [Soe Zeya Tun/Reuters]

Following the Philippines, Taiwan and Hong Kong, Japan became the latest country to deny entry to all international cruise ships.

Tokyo's scramble to close its ports came on the heels of a surge in confirmed cases on board the cruise ship Diamond Princess, which is currently under quarantine and docked in Yokohama.

On Thursday, Japan's health officials confirmed 218 passengers and crew, as well as one quarantine officer, have been infected making it the largest cluster of infections outside China, the source of the COVID19 outbreak.

Floating petri dish

Much like the virus, the fear that any cruise ship can be a floating petri dish has also been spreading. However, health experts said ships can be safer than aircraft.

"Cruise ships are much less a risk than, for example, planes for global spread of a virus," said Dr Marc-Alain Widdowson, director of the Institute of Tropical Medicine in Antwerp, Belgium, told Al Jazeera. "This is because ships are usually at sea for several days, so this gives time for symptoms to show in people incubating the disease."

However, the length of a sea voyage and contained nature of a ship do present other risks.

"If someone does fall sick, it is possible to confine them to cabins, but the ship facilities are often not equipped to deal with many severe illnesses at a time. If someone is very sick on the sea, it is difficult to evacuate them," Widdowson added. "Therefore, a cruise ship is a place for viruses and other microbes to rapidly spread."

The MS Westerdam has a lready been barred twice from disembarking in Manila last week and Taiwan on Monday [File: Becky Bohrer/AP]

Originally scheduled for a two-week turnaround in Yokohama on February 15 - in lieu of a return to Shanghai - the Westerdam, operated by Holland American Lines, last docked in Hong Kong on February 1, receiving 800 more passengers.

After that, the Dutch-flagged luxury liner was barred from docking in Manila in the Philippines, Kaohsiung in Taiwan, and, despite a request by the US State Department, the American territory of Guam. Malaysia and Thailand also turned it away.

"@HALcruises made a big mistake taking us into Hong Kong given the situation," passenger Stephen Hansen, of Vancouver, Canada, posted on social media. But Hanson was satisfied by the operator's handling of the marine mishap and the promise of full refund.

"It all depends upon what risk and crisis management plan the cruise line had in place, and what criteria were used to justify the decision to take on more passengers," said John Ap, a tourism management professor at Macao Institute for Tourism Studies.

'Health scare'

Unlike Hansen, passengers of another cruise were less lucky with getting their money back. Cruise liner Norwegian Jade, which was scheduled to board in Hong Kong, switched port to Singapore.

The operator, Norwegian Cruise Line, refused to offer a refund to customers who cancelled, according to US media reports.

Since February 6, Hong Kong government officials have ordered closed both of the city's cruise terminals, after the World Dream cruise ship docked with nearly 4,000 passengers and crew requiring quarantine.

Passengers of the World Dream ship disembark on Sunday in Hong Kong after testing negative for coronavirus [Jerome Favre/EPA]

Emergency response kicked into high gear after the ship's operator revealed that after dropping off eight mainland Chinese passengers later found to be infected, the ship made four trips between Hong Kong and Vietnam.

In response to the outbreak, Cruise Lines International Association whose member lines make up more than 90 percent of ocean-going cruise capacity worldwide, issued new policies requiring pre-boarding screening. It has also barred anyone who has travelled from or transited via China, including Hong Kong and Macau, two weeks before departure or has been in close contact with anyone visiting the aforementioned places.

But even long after disembarking, cruise passengers may still cause a health scare.

Last Saturday, SuperStar Aquarius was allowed back berthing at its home port of Keelung near Taipei. The ship was exempted from Taiwan's ban as 90 percent of the 1,750 passengers are from the island.

Even though no infected cases were found, the passengers have been asked to self-quarantine for 14 days. But one wayward passenger flouted the order and took a dip in a fitness club pool the day after. The club has voluntarily closed its doors to disinfect its facilities.

The current rush to close ports in Asia follows a ban on all cruise ships entering South Pacific Islands which has been in place since late January. Several Caribbean ports turned away German cruise ship AIDA Perla because some passengers were showing signs of suspected coronavirus infections.

All this followed an initial false alarm on January 30, when nearly 6,000 passengers and crew members were kept on board the Costa Smeralda cruise ship in Italy while officials investigated a potential coronavirus case of a 54-year-old Chinese passenger who showed flu-like symptoms.

The tests turned out to be negative.