Norovirus Outbreak on Cruise Ship Sickens Over 600

By Kim Smiley 

A cruise ship has once again made national headlines for a negative reason.  A norovirus outbreak on Royal Caribbean’s Explorer of the Seas sickened nearly 700 hundred people during a cruise that ended on January 29, 2014.  Noroviruses are extremely unpleasant and cause extreme stomach cramps, vomiting and diarrhea, not exactly the stuff fantastic vacation memories are made of.  According to the Centers for Disease Control and Prevention (CDC) there have been 56 gastrointestinal outbreaks on cruise ships in the past five years, but this outbreak is notable because it was one of the largest in 20 years.

This incident can be analyzed by building a Cause Map, a visual format for performing a root cause analysis that intuitively shows the cause-and-effect relationships between the causes that contribute to an issue.  A Cause Map is built by asking “why” questions and documenting the answers. ( To view a high level Cause Map of this example, click on “Download PDF”.)

In this example, the initial source of the norovirus is not known and may not be able to be determined, but a Cause Map can still be helpful in understanding how the outbreak spread and how the outbreak impacts the goals of the company.  The CDC did investigate the outbreak, but it can be difficult to determine how the norovirus was brought onboard.   Noroviruses are common, especially during the January through April peak season for norovirus infections, and cruise ships need to have a plan to deal with sick passengers because simply preventing a norovirus from coming onboard isn’t realistic.

Once a person infected with a norovirus is onboard a cruise ship, the illness can spread quickly because is highly contagious.  Noroviruses can be transmitted by contact with an infected person, consuming contaminated food and even touching contaminated surfaces such as stair handrails.  Cruise ships, along with other confined spaces such as nursing homes, are particularly susceptible to fast spreading outbreaks of norovirus because there is a large number of people in a small space and it can be a challenge to isolate sick people.  Many cruise ships also serve meals buffet style which can pass the virus quickly to a large number of people.

The cruise ship did have a plan in place to help mitigate any outbreaks and the number of ill passengers was decreasing by the time the ship returned to port.  Sick passengers were isolated to their cabins and crew increased cleaning and sanitation of the ship during the cruise.  The ship was also given an especially thorough cleaning and extra sanitizing prior to departure of the next cruise.  In order to track and help cruise ships prevent outbreaks the CDC also runs a Vessel Sanitation Program, which monitors illness at sea and provides information about disease prevention.  If plan to take a cruise, the best way you can protect yourself is by frequently and thoroughly washing your hands with soap and water.

Visit our previous blogs if you are interested in learning more about other cruise ship examples:

Engine Room Fire Results in Cruise Ship Nightmare

Cruise Ship Loses Power

The Salvage Process of Costa Concordia