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Cruisin’ for a Bruisin’: Norovirus Rules the High Seas

I’ve never been on a cruise, but my mother loves them. The idea of living in a confined space with 3,000 other shipmates for an extended period of time scares me. So when I see stories about the recent tragedies with the Costa Concordia and Costa Allegra, my fears seem justified. These tragedies, however, overshadow another problem that the cruise industry deals with every day — norovirus. This stowaway has been wreaking havoc on cruises for decades. 


The Centers for Disease Control and Prevention (CDC) estimates there are 20 million cases of norovirus every year resulting in 70,000 hospitalizations and 800 deaths. The symptoms are vomiting, diarrhea, nausea and stomach cramping. Most people will be sick for only a couple of days, but they may be contagious for up to 3 days. Typically, people become exposed to norovirus from contaminated food or water, but this can spread to others from close personal contact. So if a ship serves contaminated food resulting in a couple dozen norovirus cases, this can spread across the ship, bringing the number of cases into the hundreds. 

Lately, norovirus has been cruising with a vengeance. In early February, the Ruby Princess and Crown Princess both had outbreaks involving nearly 500 people. A few days later, the Crown Princess again returned to port with 364 sick passengers and 32 sick crew. More recently, the Celebrity Cruises Celebrity Silhouette reported to St. Maarten with 185 cases of suspected norovirus aboard the ship.

Norovirus is a frequent traveller on cruises. From Jan. 1, 2003 to Feb. 16, 2012, there have been 25,338 reported cases of cruise ship illnesses. Taking into consideration all the cruise ships in operation, this might seem like an insignificant number. But I would hate to shell out thousands of dollars for a cruise only to spend it buried in the toilet with no escape. It appears the cruise ship industry has a problem preventing and containing illness on their vessels.

Why Is Norovirus So Prolific on Cruises?

Is it the romantic scenes, exotic stops or endless entertainment? Actually, It must be the intimate onboard conditions. A combination of perfect temperatures, confined spaces and 3,000 incubation vessels (people) is a dream situation for norovirus. It spreads quite freely between people in close quarters. Norovirus is very persistent and can be present in the air after someone has vomited. And on a ship, once you have a couple hundred infected people repeatedly vomiting all over the place, there really is little hope for escape. 

When norovirus was first diagnosed on cruise ships, quaternary ammonia was a common way to sanitize the ships. It was after the same ships were having repeated outbreaks even after sanitizing that investigators realized quaternary sanitizers were widely ineffective against the pathogen. Chlorine-based sanitizers are now found to be the best at controlling norovirus. Check out the EPA list of products effective against norovirus. It’s extremely important to sanitize every inch of an affected area to adequately eliminate norovirus.

CDC Oversight?

The cruise lines point to a rigorous inspection criteria implemented by the CDC to ensure everything is being done to prevent illness on their vessels. The program is called the Vessel Sanitation Program. It looks like an extensive and vigorous inspection program. The scores and inspections are available for public review. There is a list of all the ships that have scored 100, the best possible score. Sounds great, right? Well, after taking a closer look, all 3 ships mentioned above had perfect scores on their last inspections. But if they had perfect scores and still had an outbreak, is the program really working, or is norovirus impossible to defend against?

Upon further investigation, I found the scores were quite misleading. All 3 ships had several violations but didn’t receive any points deducted from their scores. Many of the violations directly related to spreading illness. Here is what was found:

Crown Princess

Inspection date: 11/19/11

Violations: 33 total including temperature-abused food, and “no procedures in the Outbreak Prevention and Response Plan for returning the vessel to normal operating conditions after an outbreak,” “no disinfectant in the diaper changing station,” and “rat guards were not placed correctly around the rope while the ship was docked, which could allow rodents to enter the ship.”

Ruby Princess

Inspection date: 11/10/11

Violations: 27 total including sick crew members not reporting to the medical center in a timely manner, no established washing procedure for ice buckets and no way of assuring each ice bucket is returned to the same cabin from where it was removed, no procedure in the Outbreak Prevention and Response Plan for notifying embarking passengers following an outbreak voyage, improper disinfection procedure for cleaning up a fecal accident, and staff not monitoring recreational water facilities for combined chlorine residual (that kills bacteria in the water).

Celebrity Silhouette

Inspection date: 12/18/11

Violations: 28 total including a cleaning employee working while sick, no serving utensils for apples in several buffet lines (which contributes to cross-contamination for patrons), and the Outbreak Prevention and Response Plan did not include procedures for returning the vessel to normal operating conditions after an outbreak.

These don’t look like perfect inspections to me. If a ship can get 2 dozen violations and still receive a perfect score, where’s the incentive? I know many of you reading this love cruises and will continue to go on them. That’s great, but next time, do your homework.

Check out cruise ship inspections posted by the CDC, but don’t pay so much attention to the scores — read the reports. Next, visit Cruise Ship Norovirus, a very informative and up-to-date website on cruise ship illnesses. 

If you happen to be reading this while on a cruise, don’t panic. Wash your hands frequently and stay out of the path of sick passengers. If you’re already sick, stay in your room so you don’t infect others and drink lots of fluids. Norovirus can strike anywhere and anytime. Be prepared. 

What do you think? Is the cruise ship industry doing enough to prevent illness, or is it inevitable that every year they will be plagued with outbreaks? 


Dennis Keith is founder and CEO of the consulting company Respro Food Safety Professionals. ‘Cruisin’ for a Bruisin’: Norovirus Rules the High Seas” first appeared on his Utah Food Safety Blog March 3, 2012.

© Food Safety News
  • John Cornyn

    Your article appears to omit or ignore the distinct possibility that some of the outbreaks are due to food consumed off-shore in local area restaurants. While there is always a need for the cruise lines to better manage its food service operations and employees, fairness suggests that you address what happens when passengers and crew return to the ship after eating at what should be suspect restaurants.

  • The cruise lines tout the luxury and convenience of their massive ships, but that also means that crews have the responsibility of making sure the entire ship is safe for every passenger. Norovirus has proven that cruise ships need to better address ways to keep ships clean, especially once an outbreak occurs. Clearly these ships are not equipped to deal with hundreds of violently ill passengers.