Cruise ships have been in the news a lot this month with reports of Norovirus sickening hundreds of passengers and even cutting cruises short so that ships could be deep cleaned to avoid spreading the virus to passengers on subsequent sailings. It's almost become an annual ritual for reporters to do stories on the "cruise ship disease." However, when hundreds of cruise passengers report to the infirmary with similar symptoms, does that necessarily mean their
ship is SICK? Hardly. But you'd never know that from news reports about nasty cruise ship diseases that attack unsuspecting vacationers.
Fact vs. Rumor
Let's face the facts first—travel by cruise ship often brings together large numbers of people from different regions of North America, as well as other parts of the world. In confined quarters, certain respiratory and gastrointestinal diseases can quickly spread from person-to-person contact. In addition, when ships dock and passengers go ashore, they might be at risk for diseases prevalent in the ports of call they visit. It is even quite possible that some passengers who become ill during a cruise were infected prior to boarding and they were actually "sick" before their symptoms became apparent.
Wait a minute... before we examine specific illnesses, let's think about how and when passengers are likely to be exposed to them. Cruise ships aren't the only places where large groups of people are likely to get together and outbreaks of "flu" and the "24-hour stomach bug" are common in such places as schools, nursing homes, and even hospitals. According to Princess Cruises, "Statistics have shown that the chance of contracting Norovirus on land is 1 in 12; and 1 in 4000 on a cruise ship."
Because respiratory and gastrointestinal diseases can percolate a few days before their symptoms strike with a vengeance, it is highly likely that some passengers bring their "bugs" on board with them. Before reaching a cruise ship, many—if not most—passengers pass through airports to board airplanes (with re-circulated, stuffy air) and they may spend the night in a hotel at their embarkation port and eat in local restaurants. Each of those places are breeding grounds for germs.
While most people are unaware that they have contracted an illness before embarking, others know they are sick but go aboard anyway, not acknowledging their illness for fear of being denied boarding. They might not seek treatment once on board due to the threat of being confined to their staterooms. These "alpha passengers" can be the beginning of a ship-board epidemic!
What To Do
According to the U.S. Center for Disease Control (CDC), "Anyone who becomes ill while on a cruise ship should seek medical attention on board and see a health care provider upon returning home. Ill persons should limit contact with the general population on board as much as possible to reduce further spread of disease. People planning cruise ship travel, especially anyone older than 65 years of age, anyone with acute or chronic illnesses, or pregnant women should consult with a health care provider prior to travel for advice and possible preventive medication. Other measures to prevent the spread of infectious diseases on cruise ships include frequent hand washing and obtaining appropriate immunizations prior to travel."
Two of the most prevalent diseases that spread through cruise ship populations are Influenza and Noroviruses.
Influenza
According to studies, influenza infection among travelers is quite common; hence, it may rank with hepatitis A as one of the most common vaccine-preventable travelers' diseases. Seasonal epidemics of influenza generally occur during the winter months on an annual or near annual basis and can cause disease in all age groups. While rates of infection are highest among infants, children, and adolescents, rates of serious illness and death are highest among persons over 65 years of age and persons of any age who have medical conditions that place them at high risk for complications from influenza (e.g., chronic cardiopulmonary disease).
The risk for exposure to influenza while traveling depends on the time of year and destination. In the tropics, influenza can occur throughout the year, while in the temperate regions of the Southern Hemisphere most activity occurs from April through September. In temperate climates, travelers can also be exposed to influenza during the summer, especially when on board a cruise ship with travelers from areas of the world where influenza viruses are circulating. Influenza might be, at best, an inconvenience; however, it can lead to complications, including life-threatening pneumonia, especially among persons at increased risk for complications. Annual influenza vaccination is the primary method for preventing influenza and its complications.
Norovirus
These are a group of related viruses that cause acute gastroenteritis in humans. Norovirus was approved as the official genus name for the group of viruses provisionally described as "Norwalk-like viruses" or NLV. The incubation period for norovirus-associated gastroenteritis is usually between 24 and 48 hours, but cases can occur within 12 hours of exposure. Norovirus infection usually presents as acute-onset vomiting, diarrhea with abdominal cramps, and nausea. Low-grade fever also occasionally occurs and vomiting is more common in children. Dehydration is the most common complication, especially among the young and elderly, and may require medical attention. Symptoms generally last 24 to 60 hours. Recovery is usually complete and there is no evidence of any serious long-term effect.
Highly contagious Noroviruses are transmitted primarily through the fecal-oral route, either by consumption of contaminated food or water or by direct person-to-person spread. During outbreaks of norovirus gastroenteritis, several modes of transmission have been documented; for example, initial food borne transmission in a restaurant, followed by secondary person-to-person transmission to household contacts.
Norovirus is often termed the "cruise ship virus," even thought the vast majority—some 60 percent to 80 percent of outbreaks—occur on land. However, it is often more unmistakable on cruise ships because all sick passengers and crewmembers are treated by the same physician, who is required to prepare a special report for the CDC if an outbreak affects 2% or more of the passengers or crew. The CDC launches and investigation if 3% of passengers or crewmembers become ill.
What else to do?
First and foremost—WASH your hands often with hot water and soap. A waterless, sanitizing hand cleaner is also recommended for times when soap and water aren't available (they are fairly effective and come in travel size bottles). Some passengers even go so far as to pack disinfectant wipes or a small aerosol can of germ-killing spray to treat their stateroom furnishings, bedding, and bathrooms before using them.
If you get sick, seek medical treatment and try not to infect other passengers.
While other cruise lines, most notably Norwegian and MSC, have introduced ultra-private upscale ship-within-a-ship decks on their newest vessels, Celebrity Cruises plans to offer a somewhat similar experience on their existing fleet. Their most discerning guests who desire the very best will soon be able to indulge themselves with special perks for booking the new 'Suite Class' experience that will be fully introduced on Celebrity's ships during April 2015. 
