CNN  — 

Cruise lines have become the latest segment of the travel industry to be hit by the coronavirus outbreak, with Japanese authorities revealing that an infected passenger flew into Tokyo and spent a few days aboard a Princess Cruises ship.

On Monday, February 3 Japan quarantined the ship, which arrived at a port in Yokohama after a former passenger was found infected with Wuhan coronavirus a few days earlier.

The roughly 2,500 passengers and 1,000 crew members on Princess Cruise’s “Diamond Princess” ship will have to remain on the vessel until at least the evening of February 4 while quarantine officers complete tests of several passengers who fell ill, according to the Health Ministry.

Cruise companies adopt special measures

An elderly man who traveled on a cruise aboard the Diamond Princess was found to be infected with the Wuhan coronavirus.

So how are cruise lines protecting passengers against the Wuhan coronavirus?

According to the Cruise Lines International Association (CLIA), the world’s largest cruise industry trade association, member lines are continually assessing and modifying policies and procedures as developments emerge.

“All booked guests who have traveled to/from or through mainland China in the 14 days prior to their departure will not be allowed to sail, consistent with guidelines issued by CLIA,” Carnival USA said in a statement issued in late January.

Norwegian Cruise Line, meanwhile, has implemented mandatory temperature checks for all passengers, regardless of origin or destination. Travelers whose temperatures are above 100.4 degrees Fahrenheit (38 C) will not be allowed to board.

Several lines have opted to skip or reschedule port calls in mainland China and Hong Kong.

MSC Cruises, for example, canceled Shanghai stops and replaced them with Ho Chi Minh City and Singapore, while Crystal Cruises subbed in Taipei for Hong Kong.

Close quarters

Cruise ships are sometimes given the derisive nickname of “floating Petri dishes,” due to the fact that guests are in a contained area for extended periods of time – after all, it’s not like you can just hop off the boat for a break when you’re in open sea.

Though coronavirus is currently on everyone’s minds, one of the biggest concerns on board cruise ships is the norovirus – meaning cleanliness has long been a priority for the cruise industry.

According to the Centers for Disease Control (CDC) in the United States, norovirus – the leading cause of acute gastroenteritis – is most likely to occur when people are in close quarters.

“When you have a lot people in a closed environment, whether it’s a nursing home or an institution like a school or a cruise ship, it’s more like an incubator,” Claire Panosian, a professor emeritus in the division of infectious diseases at the David Geffen School of Medicine at UCLA, told CNN Health in 2019.

“People are in closer proximity and viruses can end up in the air and on surfaces that people touch.”

Cruise ship companies across the world do their part to prevent norovirus, E.Coli, and other diseases by emphasizing hygiene on board – for example, having hand sanitizer stations easily accessible in common areas and requiring staff members who handle food to wear gloves.

What to know

But beyond knowing what on-board crew members are doing, how can you take control of your health while on a cruise?

The CDC advises washing your hands frequently – not only before and after eating but whenever you touch shared surfaces like ship railings.

It also recommends getting your vaccinations up to date, avoiding food and drink from questionable sources while you are on shore excursions, and coughing or sneezing into a tissue or your elbow instead of your hand.

People with underlying conditions or who are recovering from illness should consider postponing their travel, as they are more susceptible to viruses. It’s never a bad idea to consult your physician ahead of time.

Travel insurance can also be a good idea.

While many cruise lines offer their own insurance, third party vendors are generally a safer bet, as their sickness coverage may be more robust.

For cruise ships registered in the United States, the CDC’s Vessel Sanitation Program has an online index where you can get health and safety information about the specific vessel you will be sailing on ahead of time.

CNN’s Nicole Chavez, Junko Ogura and Yoko Wakatsuki contributed reporting.