cruise ship gastroenteritis outbreak

Nearly 140 people onboard a cruise ship sick in gastrointestinal illness outbreak

Around 140 people have fallen sick with a gastrointestinal illness onboard the Cunard Queen Victoria cruise ship that docked in Fort Lauderdale, Florida, on Jan. 22 when the CDC began monitoring the outbreak.

According to the U.S. Centers for Disease Control and Prevention , 123 passengers and 16 crew members have reported being ill during a three-week leg of the voyage as of Thursday. Around 1,800 passengers and 960 crew members are onboard the ship in total.

The predominant symptoms of the gastrointestinal illness include diarrhea and vomiting. The cause of the outbreak remains unknown, according to the CDC.

The Queen Victoria is on a 107-night world voyage. The cruise ship is scheduled to stop in San Francisco on Feb. 6 and Honolulu on Feb. 12 before sailing to countries in Oceania, according to the Cunard website . 

In response to the outbreak, the Queen Victoria crew has reportedly "increased cleaning and disinfection procedures" and "isolated ill passengers and crew." 

"Cunard confirms that a small number of guests had reported symptoms of gastrointestinal illness on board Queen Victoria, Cunard Cruise Line told NBC News in a statement.

"They immediately activated their enhanced health and safety protocols to ensure the well-being of all guests and crew on board. Measures have been effective,” Cunard added.

The CDC's Vessel Sanitation Program continues to remotely monitor the situation, including "reviewing the ship's outbreak response and sanitation procedures."

Medical staff on cruise ships under U.S. jurisdiction are required to report gastrointestinal illness cases to the Vessel Sanitation Program when at least two percent of people onboard are infected.

Katherine Itoh is a news associate for NBC News.

• CruiseMapper
• Ships and Lines

Cruise Ship Norovirus Outbreaks

Here are listed latest cruise ship Norovirus outbreaks on passenger ships, with information what is and how to avoid Norovirus on cruise ships, CDC reports, and news updates.

From the following links, you can skip the intro and jump directly to illness outbreaks in 2024 , 2023 , 2022 , 2020 , 2019 , 2018 , 2017 , 2016 , 2015 , 2014 , 2013 , 2012 , also read about Zika virus , Seasickness , Hospital (shipboard infirmary) and Mercy Ships (hospital ship Africa Mercy) .

Note: The following CruiseMapper link provides information on Coronavirus/COVID outbreaks on cruise ships .

Norovirus outbreaks on cruise ships in 2024

Cruise norovirus outbreaks updates.

Norovirus on ships is spread through contaminated water, foods and surfaces (public restrooms, railings, doorknobs, handles, board games-cards-puzzles-toys, etc). Norovirus withstands chlorine, prolonged exposure outside the body, as well as temperature extremes. Like a virus, Norwalk can't be effectively treated with antibiotics, making it extremely difficult to eliminate in closed environments - like cruise vessels.

Norovirus may incubate up to 48 hours before the symptoms appear. This makes it difficult to restrict an outbreak. Noro symptoms include nausea, vomiting (kids more than adults, abdominal cramps, diarrhea, general weakness, low fever, headache, muscle aches. The illness could last up to 5 days (depending on the person's age, general health, and severity of the exposure to the virus. Recovered patients can still spread the virus for up to 2 weeks.

Quarantining the ill passengers and crew to their cabins is mandatory (at least for 48 hours) to slow the outbreak's spread. Failing to comply with the crew's orders results in fines or even discharge from the ship.

CruiseMapper's Norovirus survey is based on official data from CDC.gov (USA's "Centers for Disease Control and Prevention"). CDC's "Vessel Sanitation Program" assists the cruise tourism industry in preventing and controlling the transmission and spread of gastrointestinal illnesses (Norovirus, ETEC) on passenger ships calling on US seaports.

This program operates under the authority of the Public Health Service Act (fda.gov, "Quarantine and Inspection Regulations to Control Communicable Diseases"). CDC sanitation inspections on passenger ships are conducted twice a year. Scores of 86 are considered passing. Among the issues that CDC health inspectors usually find on board and report are:

• food debris
• dead insects
• insect droppings
• records indicating crewmembers (including cooks and galley staff) working while sick (suffering from gastrointestinal disorders or with acute gastroenteritis/AGE symptoms)
• cracked/corroded equipment
• soiled cutting boards
• food served undercooked
• lack of safety instruction signs.

CDC cruise ship Norovirus reports

Cruise ship outbreaks are reported (posted on the CDC website) when the illness incident meets the following criteria:

• The ship falls within the purview of the Vessel Sanitation Program (VSP). This means if it carries 13+ passengers and has a foreign cruise itinerary with US ports of call in it. Keep in mind, that most departures are from US-based home ports.
• The ship cruise itinerary length is between 3 and 21 days,
• The ship carries 100+ passengers.
• The percentage of infected passengers or crew (cases reported to the ship's med staff) during the cruise is 3% or more. This means small outbreaks on cruise ships will not be reported to the CDC.

CDC cruise ship inspection fees are payable by the shipowner. Fees are based on the vessel's size. VSP doesn't charge fees for consultations related to shipping facilities renovations or new ships. Inspection fees are as follows.

• Small ships (under 3000 GT/gross tons) pay USD 1500 per inspection.
• Small ships (between 3000-15000 GT) pay USD 3000 per inspection.
• Medium ships (between 15000-30000 GT) pay USD 6000 per inspection.
• Large ships (between 30000-60000 GT) pay USD 9000 per inspection.
• Extra-large ships (between 60000-120000 GT) pay USD 12000 per inspection.
• Mega-liners (above 120000 GT) pay USD 18000 per inspection.

Note: When the itinerary doesn't include US cruise ports, the ship is not required to report to CDC, thus no official illness outbreak report would be issued.

CDC ship illness outbreak investigations

VSP (abbrev "Vessel Sanitation Program") monitors CDC's observations on illness patterns for GI (gastrointestinal) outbreaks on passenger shipping vessels ( ferries and cruise ships ).

• VSP conducts outbreak investigations only in cases with 3% or more passengers or crew reported sick with GI symptoms. VSP may also conduct outbreak investigations in cases of unusual GI illness patterns (even if the rate is less than 3%).
• VSP conducts outbreak investigations only on vessels visiting ports in the USA or which are within 15 days of arriving at a US port.
• When an outbreak occurs, VSP asks for ship logs and infirmary records of reported GI cases (symptoms and timing) and illness distribution (among passengers/crew, during each day of the cruise).
• VSP staff usually boards the vessel for epidemiological assessment, interviews, distribution and analysis of illness questionnaires, monitoring cleaning procedures.
• Lab investigations - the onboard med staff often collects stool, vomit, blood specimens, which are then sent to land-based labs to confirm the illness cause.

During the onboard illness outbreak, VSP requires the cruise company to activate the "Outbreak Prevention and Response Plan" (vessel's response to illness cases).

During an outbreak:

• Cleaning and disinfection frequencies are Increased.
• Self-service buffets are stopped.
• All infected (pax/crew) are quarantined to their staterooms/cabins
• Clinical specimens are collected for analysis.
• Daily updates are provided to VSP (cases counts and measures reports)
• All passengers and crew are alerted of the illness.
• Upon boarding on the next scheduled cruise, passengers are notified about the previous voyage's outbreak.
• Occasionally, VSP requires the company to notify port authorities and also to perform cleaning and disinfection in cruise port terminal buildings.

Illness outbreaks on cruise ships (annual statistics)

The following statistics show the number of cruise ship illness outbreaks in recent years. You can compare the number of reports (CDC and news media sources) and the total number of infected (passengers and crew).

In 2014, Time Magazine published the article "The 13 Worst Norovirus Outbreaks on Cruise Ships". In it, the overall winner was Princess Cruises with 5 epidemic illness outbreaks:

• Coral Princess (February 2009, infected 271)
• Crown Princess (January 2010, infected 396)
• Crown Princess (February 2012, infected 363)
• Sun Princess (July 2012, infected 216)
• Ruby Princess (March 2013, infected 276)

Norovirus outbreaks 2023 reports

Norovirus outbreaks 2022 reports, norovirus outbreaks 2020 reports, outbreaks 2019 reports.

In the following table, you can see all 2019-reported Norovirus outbreaks on cruise ships. The listed statistical data is based on CDC or news media reports. It shows the number of sick passengers and crew (with the respective percentage to all), along with the corresponding CDC report pages (if available) as outgoing links.

Note: When the itinerary doesn't include US cruise ports, the ship is not required to report to CDC, thus no official illness report would be issued.

Outbreaks 2018 reports

In 2018, the number of reported illness outbreaks on cruise ships was 15. The total number of infected was 1177 (of those 1099 passengers and 78 crew).

Outbreaks 2017 reports

In 2017, the number of reported illness outbreaks on cruise ships was 21. The total number of infected was 2535 (of those 2450 passengers and 85 crew).

Outbreaks 2016 reports

In 2016, the number of reported illness outbreaks on cruise ships was 23. The total number of infected was 2504 (of those 2378 passengers and 126 crew).

Outbreaks 2015 reports

In 2015, the number of reported illness outbreaks on cruise ships was 23. The total number of infected was 2570 (of those 2458 passengers and 112 crew).

Outbreaks 2014 reports

In 2014, the number of reported illness outbreaks on cruise ships was 17. The total number of infected was 3559 (of those 3354 passengers and 205 crew).

Outbreaks 2013 reports

In 2013, the number of reported illness outbreaks on cruise ships was 22. The total number of infected was 2385 (of those 2249 passengers and 136 crew).

• According to CDC, in 2013 from Norovirus and similar GI (gastrointestinal) illnesses suffered a total of 1409 passengers (which is 7,5% of all passengers on the inspected cruise vessels) and 96 crew/staff members (which is 1,2% of all). With nearly 12 million cruisers departing from USA and Canada ports in 2013, the Norovirus infection rate is ~0,01% of all passengers.
• It should be noted, that in the past years on many CDC inspections was concluded the Noro virus illness source was off the ship.

Outbreaks 2012 reports

In 2012, the number of reported illness outbreaks on cruise ships was 34. The total number of infected was 5542 (of those 5079 passengers and 463 crew).

Norovirus on cruise ships

All important things you should know about the "cruise virus".

Why do Norovirus incidents happen on cruise ships? There are more than 21 million US cases reported annually, of which 1 mill related to kids. Outbreaks happen mostly during winter months and mainly in more crowded places with close quarters. Among those are schools, hospitals, nursing homes, dormitories, prisons, big resorts, bigger passenger ships (including cruise ferries ). Norovirus is often branded as "cruise ship virus" simply because on ships health officials are required to report every gastrointestinal illness incident. This means Norovirus outbreaks are reported more quickly on ships than on land. Just for comparison, the virus can afflict as many as 3000 people per day in only one big city, which is about the passenger capacity of a typical modern cruiser.

What is Norovirus infection? It's a very common, highly contagious, ruthlessly efficient and uncomfortably bad virus affecting the stomach and large intestines. Often called "stomach flu" (the med term is "Gastroenteritis") the infection results in massive vomiting and diarrhea. Sickness outbreaks are considered as such if the percentage of infected people is over 3%. The virus is not seasonal and usually not serious (in medical terms). It hits 1 in 5 people annually and is the cause of ~50% of all foodborne illness outbreaks in the USA and for ~90% of all non-bacterial gastroenteritis worldwide.

The virus is named after an outbreak in Norwalk (OH, USA). Numerous studies confirm that a quick application of hand sanitizer doesn't kill the Norovirus. It takes about 30 sec of hard rubbing with hot water and soap (including under the nails) to wash it. This virus also mutates (changing its strains). As to its efficiency - a mere 20 particles are enough to get you.

What causes Norovirus on cruise vessels is mainly contaminated food/water. When it comes to ships, it spreads mostly through physical contact with sick people or handling contaminated objects. This includes sharing food/utensils and poor hygiene (not washing hands after bathroom use). The virus also spreads fecally, so you can catch it into the onboard laundry, or while changing diapers, etc. However, many passengers likely can blame a sick crewmember for the virus. According to a survey based on 170 inspection records on ships that docked in Florida ports in 2012, on 59 cruises violations of the required illness reporting laws were reported. A total of 130 crew had gotten sick on those voyages and didn't report their illness in the required time period.

The symptoms are nausea, vomiting, diarrhea, indigestion, abdominal cramps. Also possible are mild fever and headache. It takes 1-2 days for the symptoms to appear. The illness lasts 1 to 4 days, but some people (especially elderly) may be contagious for up to 2 weeks after recovery.

What is the treatment? What to do if you got it? Obviously, the first thing is to go to the ship's infirmary (medical center) and contact the doctor. You should drink plenty of water as dehydration is a side-effect of the illness. There is no real treatment for Norovirus - you just wait it out. A few years ago an experimental Norovirus vaccine (applied as nasal spray) was developed by the "Center for Infectious Diseases and Vaccinology" (Arizona State University). The new vaccine generates a good immune response.

How to avoid Norovirus on cruise ships?

• Wash your hands often (hot water and soap), especially before/after eating and after using the bathroom
• Limit physical contacts as much as possible, pack some extra soap, a personal disinfectant (Lysol, Pepto-Bismol), oral rehydration sachets and treatments for diarrhea
• Avoid eating uncooked food (including salads and sandwiches) and food that cannot be washed (unless it can be peeled or shelled), drink only bottled liquids (preferably without ice), don't share drinks/utensils.
• Drink lots of water.
• Compensation for cruise illness. By contract, cruise lines are not required to compensate passengers who fall ill on cruises. However, they will compensate you if the itinerary was altered/canceled due to an illness outbreak. The deal may include up to 50% refund, up to 50% FCC (future cruise booking discount) or an option to cancel for a full refund plus reimbursement of airline change fees. If you have travel insurance, it covers cancellation due to illness. If you've been infected on the ship, it could also cover medical expenses and to compensate you for all days you're not on the ship before the cruise end.

The following "health advisory" list of recommended actions is often issued during gastrointestinal illness outbreak or on embarkation day (of the next scheduled voyage). It has important suggestions on how to avoid spreading the cruise ship virus infection.

• It is critical that excellent standards of personal hygiene are maintained by all on board, as well as avoiding touching surfaces, such as handrails, door handles, elevator buttons, walls.
• Report any observed evidence of vomiting or diarrhea that you may encounter on the ship.
• Ensure that you minimize direct contact with others during this time, such as handshakes, etc.
• Avoid touching your mouth.
• Wash your hands frequently and thoroughly with soap for at least 20 sec and rinse them well under running water. Ensure that you follow this procedure every time you use the WC, after coughing or sneezing, and before eating, drinking or smoking.
• Attempt to always use your own cabin toilet facilities.
• In addition to hand washing, also use the alcohol hand gels provided where available, and in particular before eating in the self-serve buffet restaurant and outdoor food outlets.
• Should you experience any symptoms of vomiting or diarrhea, return to your cabin and immediately report to the Medical Center or Front Office (Reception, if the infirmary is busy) by dialling 999.

Cruise ship virus procedures

What do they do about it? What actions do lines/operators/CDC actually take in response to a Norovirus cruise outbreak?

An "illness outbreak" is considered when 3% or more of all passengers report symptoms to the ship's med staff. In such cases, the CDC requires cruise lines to file a medical report.

The hotel staff is required to implement special cleaning and disinfection procedures for sanitizing the whole ship. To do that, they use stronger solvents, like Microbac, chlorine bleach, hydrogen peroxide. The Lido Deck's bistro/buffet service switches to manned stations. Often, salt-pepper shakers are taken off the tables. The crew starts offering precautionary tips. Sick passengers and crew are quarantined in their rooms, typically for at least 2 days. When Norovirus outbreaks can't be contained, cruise lines might also pull the ship out of service for a few days for sanitizing.

The CDC's "Vessel Sanitation Program" is for monitoring illness outbreaks on passenger ships carrying 100 or more guests on sailings from 3 to 21 days in length. The ship's medical staff is required by the CDC to maintain illness counts for each itinerary involving a stop at a US cruise port and to give CDC the number of all passengers/crew, plus the number of reported diarrhea cases during that voyage. This is done 24 hrs prior to arrival at any US port of call from a foreign port. And they file such reports even if the "illness number" is zero. This protocol only confirms that the CDC knows everything about it.

Other possible actions and results are red level ("Code Red") cleaning. The boarding/embarkation of new passengers is often delayed to permit more extensive disinfection of public areas and the cabins. Usually, a pre-embarkation health advisory is distributed to all boarding passengers. Additional med staff is sent to the ship in port to assist the disembarkation of infected passengers. Another possibility is the cruise ship to cancel all the itinerary's foreign ports of call and to return to its US home-port before the end of the voyage.

Some cruise lines offer hand-sanitizer dispensers near the ship's restaurants, Lido/pool deck areas and other more crowded public spaces in their effort to keep a lid on sickness outbreaks.

In February 2020, the shipowner cruise company Lindblad Expeditions announced the "Premium Purity" program with a shipwide cleaning system based on ACT CleanCoat technology. The program was rolled out fleetwide after a year trial. The innovative ship cleaning process is based on photocatalytic antibacterial spray that when activated by light kills viruses, bacteria, airborne microbes, mould. The disinfecting product and technology were developed by the Danish company ACT Global AS ( Copenhagen ). The spray is chemical-free, odourless, transparent and can be applied to all surfaces.

Zika virus on cruise ships

Zika virus (aka ZIKV) is a Flavivirus - from the genus of the viruses named West Nile, dengue, tick-borne encephalitis, yellow fever. These plus several other viruses may cause encephalitis (acute brain inflammation). In humans, Zika virus causes the Zika fever which is known to occur only within some equatorial regions. In 2014, Zika spread across the Pacific Ocean to French Polynesia, and soon to Easter Island. In 2015, Zika virus reached Central America, the Caribbean, and South America. In South America were recorded several pandemic outbreaks.

The most severe outbreaks were reported in Brazil, with an alarming surge in newborns with microcephaly. If the mother is infected, the virus may cause microcephaly in newborns. This is a neurodevelopmental disorder - babies are born with an underdeveloped head.

Generally, Zika is a mosquito-borne virus spread by Aedes aegypti (aka "yellow fever mosquito") and Aedes albopictus (aka "Asian tiger mosquito"). However, it became "cruise virus" since the decease can also result from intrauterine (contraceptive device), sexual intercourse, blood transfusion, lab exposure, organ/tissue transplantation, breast milk transmission.

In January 2016, the CDC issued travel guidance on affected countries and suggested using enhanced precautions and even postponing travel. Guidelines (specifically for pregnant women) were issued as well. Similar travel warnings were issued by other health agencies and governments. The CDC list of potentially dangerous for travel countries included (alphabetically) Barbados, Bolivia, Brazil, Cape Verde, Colombia, Ecuador, French Guiana, Guadeloupe, Guatemala, Guyana, Haiti, Honduras, Martinique, Mexico, Panama, Puerto Rico, Paraguay, Salvador, Samoa, St Maarten, Suriname, Venezuela.

Cruise lines should warn their pregnant passengers of the virus. Cruise ships publish daily health and safety instructions to their passengers on how to avoid mosquito bites. Zika symptoms are fever, skin rash, pain in joints, conjunctivitis (pink eye). It typically lasts from a few days to a week. For now, the illness cannot be prevented by drugs or vaccines.

"Cruise ship virus" politics

Virus outbreaks on cruise ships are actually not that uncommon. Such viral/bacterial outbreak incidents affect the vacation experience of thousands of people, being packed up in a floating resort for many days on end. In confined spaces with frequent passenger turnover (like big capacity cruise ships), it is easy for diseases to spread - whether food- or air-borne, or otherwise. However, there's a tendency to cover up the severity of this issue.

Some of the world's most famous passenger ships are listed in the virus outbreak statistics, yet one hears so little of it in mass media news. And there is no surprise in that since the "cruise illness" news are nothing but bad publicity for the companies - which is bad for a prosperous multi-billion dollar sea travel vacation business. All major cruise line companies will do their best to keep quiet about virus outbreaks on their ships. There are passenger testimonials about quarantined ships and how badly guests have been treated by the line. Virus outbreak news speaks of a lack of proper hygiene control, badly trained staff, bad ship management. The whole responsibility goes to the shipowner (cruise line company) and its management.

Major (in some cases epidemic) illness outbreaks are among the "biggies" that can bring down the brand's reputation on the market. Cruise illness issues often result in lower booking rates and cheaper prices - which is bad for the business.

So it comes as no surprise that when CDC reports an illness outbreak on some vessel, big media sources do not immediately (or ever) respond to the news. You may hear about it on your local radio station, or on your local cable operator, but not necessarily on ABC, CNN, and often not even on Yahoo and MSN news online. It's not about the passengers' health (never been) - it's about the big money that rules our world.

So keep your hands clean, keep your mind clear, always hope for the best. Bad, if meant to happen, will happen anyway, and nothing can change it.

Seasickness on cruise ships

Seasickness is physical disorientation as a result of conflicting signals received by the brain from different body senses. Our inner ear senses the ship's irregular motion, which our eyes can't see because the floor and walls are stable. Depending on individual balance, our ability to adjust to motions varies, so not everyone experiences seasickness.

Seasickness is one of the most common "cruise illnesses". Passengers sensitive to nausea or motion sickness should consult their doctors for medical recommendations prior to departure. Drugs (like Dramamine) are effective against seasickness. At the cruise ship's Infirmary, and also at Reception Desk is provided (free of charge) Meclizine. Know that the bigger the vessel the more stable it is. Also, motion in midship-located areas (including staterooms) is highly reduced in comparison to forward and aft areas.

Seasickness manifests in different ways and is always a result of the body's attempt to correct for the conflicting inputs received from its senses. Common symptoms are cold sweat, dizziness, drowsiness, headache, nausea. When such symptoms are noticed, passengers should take precautions to prevent intensifying the disorientation. The harder the symptoms, the longer the recovery.

If seasickness symptoms are accompanied by diarrhea or fever, passengers should immediately seek medical treatment for Norovirus and avoid spreading the illness to others.

How to prevent seasickness on cruise ships (tips)

Passengers prone to motion sickness are more likely to suffer seasickness. The following prevention tips can minimize discomfort, so before the cruise:

• choose more sheltered routes (clam waters). Open sea and ocean waters are rough and have larger swells, thus river cruises are among your best choices.
• Choose a large liner as larger vessels are more stable and motions are minimized.
• Book centralized/midship stateroom and/or middle deck cabin, where motions are less noticeable.
• Get a good sleep before the voyage - an energetic, well-rested body adjusts easier to new conditions.

During the cruise tips to divert seasickness symptoms include:

• Get involved in onboard activities - this will occupy your mind while the inner ear adjusts to equilibrium changes.
• Avoid napping or lying down - when the body is horizontal, the ship's motion is more pronounced.
• Avoid eating unknown foods - you don't know how your stomach may react to new food/ingredients. Avoid alcohol and acidic-fatty-spicy foods. Stay well-hydrated by drinking plenty of water.
• Walk around to adjust the body's equilibrium to the ship's motion. When on open decks, focus on the horizon to give your eyes and body similar inputs about any tilting or other motion. Depending on the symptoms' severity, it may take several hours.
• Often get fresh air, take deep breaths, keep your lungs clear.
• Some herbal remedies (in tablets or teas) also can ease the symptoms, including ginger and peppermint. Their efficacy varies by person, and are best used together with other prevention methods.

Search for medical assistance - consult the ship's physician if no actions provide relief.

Cruise ship hospital (medical care)

Cruise vessels are not "hospital ships".

Hospital ships are designated as floating medical facilities (hospitals).

Most hospital ships are navy vessels (operated by military forces) which are specifically built for use in war zones.

Attacking a hospital ship is considered a war crime, but enemy forces have the right to board them for inspections.

As of 2018, hospital ships have Brazil (6), China (5), Russia (6), USA (2), Spain (2), and India-Indonesia-Peru-Vietnam (x1).

The navies of USA, UK, Australia, China, France, Italy, Spain, Argentina, and Japan have some classes of military ships fitted with onboard hospitals.

For passengers with health concerns, medical care on cruise ships is a vital part of their travel planning. Most cruise vessels are equipped with either basic infirmary (a small clinic) or larger hospital where sick or injured passengers are treated and cared for by contractor physicians and nurses on 24-hour duty.

Shipboard hospitals as facilities and equipment vary by cruise line and vessel. Clinic's size usually depends on the ship's capacity (passengers plus crew). Generally, bigger and newer ships offer larger and better-equipped medical facilities and are served by bigger infirmary staff.

The ship's medical personnel are independent contractors. This is for limiting the cruise company's liability. There are no internationally specified regulations governing ship infirmaries and medical staffing. Each company has its own standards provided for its passengers' healthcare.

For finding the Infirmary you can use the ship deck plans . On most vessels, the medical facilities are located midship on a lower deck (for easier access and better stability) and usually among other crew facilities. Every passenger stateroom has the Infirmary's number - posted or by the cabin's phone.

Basic medical care on cruise ships

A cruise ship's medical facility can treat only passengers experiencing minor health issues - seasickness, scrapes, sunburns, etc. More severe medical emergencies can't be handled on the ship and usually require medevacs. Coast guard helicopter teams fly to the ship, hoist the passenger (accompanied by a spouse/relative and a crew nurse) and fly them to the nearest land hospital.

Infirmary's equipment and med supplies provide only emergency response and basic treatments in order to stabilize the passenger until transferred ashore.

In cases of severe emergencies, passengers with life-threatening illnesses or injuries are evacuated off the ship - either by boat (if in or near seaport) or by rescue helicopter dispatched from nearest coast guard or other station. In some cases, nearby ships with better medical facilities may assist.

Both emergency and basic care are available on the ship 24 hours a day. All treatments are paid. Outside regular opening hours fees are higher.

Like inland hospitals, medical treatments at sea are pricey. However, unlike on land, most basic travel insurance policies don't cover medical treatments on cruise ships as they are not from the patient's primary caregiver. Purchasing cruise travel insurance with health coverage (medical clauses) is highly recommended.

Shipboard medical service fees vary and are usually set by medical practitioners. General consultations incur costs similar to home visits. Prescription medications or other treatments cost extra. In most cruise ship hospitals, some supplies and medications are provided to passengers and crew for free - like aspirin, seasickness pills, small bandages.

Mercy Ships

"Mercy Ships" is a charity accredited by Better Business Bureau. It operates hospital ships since 1978 and also has currently the world's largest hospital ship (excluding navy vessels) - MV Africa Mercy.

The organization provides free humanitarian aid worldwide, including health care, community development, and health education projects, mental health, agriculture, and water development programs in mainly developing countries in Africa, Caribbean, South America, Oceania.

The organization's headquarters are in Garden Valley (Texas USA), with another 16 offices worldwide - in UK, Spain, Canada, Germany, France, Denmark, Switzerland, Belgium, Holland, Sweden, Norway, South Africa, Australia, New Zealand, South Korea.

Financial support and supplies are mainly through donations from medical companies (medications, supplies, equipment), corporations (fuel, food, building supplies), governments (port fees, drydock costs), general public and also by the crew (all volunteers on a rotational basis). The crew serves with short-term (2 weeks to 2 years) and long-term (min 2 years) contracts. Volunteer crew members occupy both medical (surgeons, dentists, nurses) and general jobs (deckhands, seamen, engineers, machinists, electricians, teachers, cooks, welders, plumbers, agriculturalists.

The crew on Mercy Ships pay all costs associated with their service - fees, travel expenses, passports, insurance, personal expenses.

As 95 of the world's top 100 largest megapolises are port cities, "hospital ships" could provide healthcare very quickly and more efficiently to large numbers of people.

MV Africa Mercy

MV Africa Mercy is a converted former rail ferry (1980-built as "Dronning Ingrid") drydock-refitted in 2007 at Cammell Laird shipyard (Hebburn, England).

The ship project started in March 1999 with the vessel's acquisition through a donation from Balcraig Foundation (UK), which purchased the boat for US$6,5 million.

Ferry's train deck was reconstructed and converted into a hospital. Project's total cost was over USD 62 million.

Vessel details include:

• Volume/GT tonnage 16572 tons
• LOA length 152 m (499 ft )
• Width 23,7 m (78 ft)
• Draft 6 m (20 ft)
• Powerplant 4x BW main engines plus diesel generators
• Propulsion two shafts with controllable pitch propellers
• Speed 19 Kn/35 kph/22 mph
• Passenger capacity 484
• Crew capacity 450
• Fleet of 28 vehicles (used in land-based operations)
• Annual drydock maintenance and refurbishment are done in Durban (South Africa).

As for facilities and amenities, the hospital ship has 5 operating rooms, Intensive Care Unit, an ophthalmic unit, CT scanner, X-Ray, labs, recovery ward (82 beds), a daycare center, a school (for all ages), library, launderette, convenience store, restaurant, gymnasium, shops, Starbucks Cafe (donated), satellite communications.

Africa Mercy has a total of 126 staterooms for the staff/crew. They are located on upper decks and include cabins for families, couples and single cabins.

Land-based operations ("Field Service") include mobile clinics providing screening for potential surgery patients, healthcare, dental care, also mental health programs, infrastructure projects.

Stomach viruses are back up on cruise ships, with hundreds falling ill

The cdc has already reported 12 outbreaks of gastrointestinal illness on cruises this year.

This story has been updated.

As cruise passengers return to the seas in force following a pandemic lull, an unwelcome side effect is also back: outbreaks of gastrointestinal illness.

According to the Centers for Disease Control and Prevention, so far this year there have been 12 outbreaks of vomiting and diarrhea that have reached the threshold for public notification on cruise ships visiting U.S. ports. The tally has already exceeded each yearly total number of outbreaks reported from 2017 to 2019.

Norovirus has been identified as the culprit in five of the 2023 cases; the others are all classified as unknown. The CDC did not immediately provide responses to questions about the increase in cases this year.

In a May outbreak, aboard Holland America Line’s Nieuw Amsterdam, 213 passengers and 35 crew reported being ill. That represents almost 11 percent of guests and about 4 percent of workers.

300 passengers and crew fall ill on Ruby Princess cruise from Texas

“Incidence of mild gastrointestinal illness among guests onboard Nieuw Amsterdam are suspected to be the common but highly contagious Norovirus, which is typically transmitted through close contact with unwell people and includes touching shared items,” Holland America Line said in an emailed statement. “The cases have been mostly mild and quickly resolving.”

The CDC says crew on the ship, which can carry more than 2,100 passengers, increased cleaning and disinfection procedures and collected stool specimens to send to a lab to confirm the cause.

According to a CDC norovirus tracking network that uses information from 14 states, there were 735 outbreaks reported from August through April 23. There were 907 during the same period of the 2021-2022 norovirus season. Norovirus causes 19 million to 21 million illnesses on average every year in the United States, the agency says .

Outbreaks of gastrointestinal illness plummeted during the pandemic, which shut down the cruise industry for more than a year and forced a slow return with multiple health precautions in place. There were no reported cases in 2020, followed by one in 2021 and four last year.

William Schaffner, a professor of infectious diseases at the Vanderbilt University School of Medicine in Nashville, told The Washington Post last year that the lower number of cruises, reduced concentration of passengers and coronavirus precautions were all factors in the drop in cases.

“The more rigorous we are with all of these hygienic measures, there’s spillover to other infectious agents,” he said.

Love that cheap cruise price? Don't forget the boatload of fees.

Health authorities say cruise passengers should wash their hands often and leave the area if they see someone get sick. If people are sick before a cruise, they should ask about alternative options and ask a doctor whether it’s safe to sail.

The Cruise Lines International Association says incidents of gastrointestinal illness are “quite rare” on ships, pointing to the millions who get sick every year on land. The group said in a statement that crew members clean and sanitize using practices developed with public health authorities, including the CDC.

“All of the efforts made by cruise ship crews cannot replace the responsibility that rests with each and every individual,” the association said. “Passengers and crew alike must also be committed to keeping themselves, their family and their fellow travelers healthy.”

Through its Vessel Sanitation Program , the CDC inspects cruise ships, monitors illness, trains crew and provides public health information. The agency releases information on outbreaks when 3 percent or more of passengers or crew report symptoms to medical staff on board.

“Norovirus can be especially challenging to control on cruise ships because of the close living quarters, shared dining areas, and rapid turnover of passengers,” the CDC says. “When the ship docks, norovirus can be brought on board in contaminated food or water or by passengers who were infected while ashore.”

Because norovirus can linger on surfaces and resists many common disinfectants, it can result in outbreaks on back-to-back cruises. Still, the agency says that norovirus on cruise ships only account for 1 percent of reported outbreaks of the illness and notes that “acute gastrointestinal illness is relatively infrequent” on ships.

“Health officials track illness on cruise ships,” the CDC says . “So outbreaks are found and reported more quickly on a cruise ship than on land.”

More cruise news

Living at sea: Travelers on a 9-month world cruise are going viral on social media. For some travelers, not even nine months was enough time on a ship; they sold cars, moved out of their homes and prepared to set sail for three years . That plan fell apart, but a 3.5-year version is waiting in the wings.

Passengers beware: It’s not all buffets and dance contests. Crime data reported by cruise lines show that the number of sex crimes has increased compared to previous years. And though man-overboard cases are rare, they are usually deadly .

The more you know: If you’re cruise-curious, here are six tips from a newcomer. Remember that in most cases, extra fees and add-ons will increase the seemingly cheap price of a sailing. And if you happen to get sick , know what to expect on board.

Grand Princess cruise ship had COVID-19, gastroenteritis outbreaks on previous voyage before coming to Adelaide

A cruise liner that had been dealing with cases of COVID-19 and gastroenteritis has arrived in Adelaide.

Key points:

• The Grand Princess cruise ship has arrived in Adelaide
• SA Health says the cruise ship had dealt with an outbreak of COVID-19 and gastro
• It says the number of cases for both illnesses have reduced after a deep clean of the ship in Melbourne

In a statement the ship's operator Princess Cruises said the Grand Princess arrived in Outer Harbour in Adelaide's north-western suburbs Monday  morning on day two of a four-day round trip from Melbourne.

"On the previous voyage (a 14-days round trip cruise from Melbourne to Queensland) a number of people reported to the Medical Centre with symptoms of respiratory illness and acute gastrointestinal illness," it said.

"While most guests were unaffected by illness on that voyage, we proactively launched a comprehensive disinfection program, developed in coordination with international health authorities to prevent further spread."

"In an abundance of caution, there will be another disinfection program carried out on board the ship in Adelaide today before Grand Princess returns to Melbourne on Wednesday 15 November."

The cruise operator said there is no current "dual outbreak" of illness on the ship.

"While we do not provide numbers of unwell guests we can say that the number of guests with symptoms are in the single digits," it said.

"Some guests have disembarked in Adelaide today after completing their holiday."

SA Chief Public Health Officer Nicola Spurrier said there were five cases of gastro on board the ship when it arrived, and eight cases of "COVID-like infection".

The health department said it had been informed by the ship's doctor that "the outbreaks have been declared over and the few remaining cases are consistent with numbers you would expect on any cruise".

"The ship docked in Melbourne on Saturday to undergo a clean, with all passengers off while this was undertaken," SA Health said.

The Grand Princess has a capacity of 4,000, including crew members. 

'Vomit smells everywhere'

Passenger Jody, who was on board with 10 other family members including her eight-year-old daughter, said she had been desperately trying to get her overflowing toilet fixed.

She said staff had  told her the issue had been resolved but water was still leaking from the wall behind the toilet.

"We've got towels everywhere ... the room has a funky smell with the toilet overflowing," she said.

She said she and her child have not been sick, but were worried about being exposed to the virus.

"There are vomit smells everywhere," she said.

"Someone threw up in the elevator and it still smells."

The ABC spoke with Jody this morning while the ship was docked in Adelaide and she was waiting to disembark.

Passenger Diana McElligott, who was on the cruise ship for 18 days, said she was not informed about COVID-19 cases on board.

"We weren't told to wear masks, we were told to be vigilant with washing and stuff like that but never heard anything about the COVID," she said.

"They should have told us if there was [cases] on board.

"Not a lot of staff were wearing masks, only in the dining room."

Ill guests disembarked separately

Premier Peter Malinauskas said "the bulk of the illnesses" happened before the ship arrived at Melbourne on the weekend.

"When that cruise ship got to Melbourne, it was disembarked and given a thorough and deep clean. Essentially people who got back onto that cruise ship were effectively new passengers," he told ABC Radio Adelaide.

"0.6 per cent of the people on the cruise ship suffered gastro."

He said people who were ill disembarked the ship separately when they got to Adelaide while those with symptoms are told to stay on the boat and not go on tours.

Anne, who cancelled her cruise trip due to injuries, told ABC Radio Adelaide her friends have been sick with both COVID-19 and norovirus on board the Grand Princess, and have been quarantined in their cabins for most of their holiday.

"They said it's been quite horrendous, they've been overrun with cases in the medical centre, a lot of people have been on drips," she said.

"They've been sick since November 1, just after they got on, and they're still sick now, so they went from one disease to the next."

She said her friends on board wore masks and sanitised regularly, but still felt ill.

Passenger David Weeder, who had been travelling with his wife for 19 days, said crew on the ship kept the passengers informed about the outbreaks.

"I had a few incidents, I think it was lucky we escaped without anything, it's just something that goes around," he said.

Tour Guides Association president told ABC Radio Adelaide that passengers disembarking in Adelaide are expected to join tours visiting Hahndorf and wineries in the Barossa Valley.

He said he would take precautionary measures like wearing masks and using sanitisers while travelling with visitors from the ship.

"I'm hoping there's some kind of checking process before passengers get actually on a tour," he said. 

Company handled outbreak 'extremely well', says health boss

SA Chief Public Health Officer Nicola Spurrier said the health department had stayed in contact with Princess Cruises, and commented the company had done "extremely well" amid "some challenges".

"I commend the company, they have very good infection protection and control mechanisms in place and protocols to deal with outbreaks," Professor Spurrier said.

"Those outbreaks came down very quickly."

Professor Spurrier's comments came amid a push for older people, particularly those in residential aged care, and immunocompromised people to get COVID-19 vaccine boosters, with the state recording a nearly 50 per cent rise in cases in just a week.

• X (formerly Twitter)

Related Stories

Cruise liner bound for adelaide suffers dual outbreaks of covid and gastro.

New COVID wave hitting SA and increasing cases — but Pirola variant not to blame

Multiple gastro outbreaks across SA as data reveals rotavirus cases doubled in past year

• Infectious Diseases (Other)
• Outer Harbor
• Port Adelaide
• Travel Health and Safety
• Travel and Tourism (Lifestyle and Leisure)

• Cruise News

Gastro Outbreak Hits Luxury Cruise Ship

• April 18, 2024

The Centers for Disease Control and Prevention (CDC) reported a gastrointestinal viral outbreak that sickened several cruise ship guests earlier this week.

Twenty-eight guests on Silversea Cruises’ Silver Nova, along with one crew member, fell ill. This represented over 4% of the passengers aboard (required for CDC reporting). 

Fourth cruise ship outbreak of the year

The CDC monitored the outbreak as the ship completed a 16-day sailing and docked at Port Everglades earlier this week.

The ship departed Peru and made several port calls in South America, the Caribbean, and Mexico. The CDC hasn’t confirmed this, although symptoms disclosed, like diarrhea, make Norovirus a possible cause. 

So far this year, three cruise ship outbreaks have been attributed to Norovirus: on Celebrity Constellation, Cunard’s Queen Victoria, and aboard Holland America Line’s ms Koningsdam .

The CDC said sick guests were isolated in their staterooms, and Silversea has implemented more stringent deep cleaning and disinfection measures.

The agency said the cruise line “made announcements of the outbreak, encourage case reporting, and encourage good hand hygiene.”

Silver Nova departed on Monday for a 20-night Panama Canal transit to San Francisco.

Silver Nova was christened in January 2024, and the CDC has yet to receive its bi-annual sanitation inspection from the Vessel Sanitation Program .

Last year, there were 14 cruise ship outbreaks, all but one of which were attributed to Norovirus. Princess Cruises and Celebrity Cruises each had three separate outbreaks.

The CDC said the Virgin Voyages ‘ Scarlet Lady illness was caused by salmonella and E. coli.

The CDC says the Norovirus bug can be extremely contagious and is the leading cause of foodborne illness.

It generally spreads through contaminated food and water or by touching surfaces or other objects already contaminated by the virus.

Recent Posts

Sun princess christened in barcelona by hannah waddingham, princess cruises [photos], construction starts for royal caribbean’s private beach club in nassau, princess introduces new sanctuary collection on sun princess and star princess, norwegian’s next cruise ship floated out at shipyard, share this post, related posts.

MSC and Mercy Ships To Build State-of-the-Art Hospital Vessel

New Consumer Law Mandates Clear Pricing for Cruise Lines

Bringing you 15 years of cruise industry experience. Cruise Radio prioritizes well-balanced cruise news coverage and accurate reporting, paired with ship reviews and tips.   

Quick links

Cruise Radio, LLC © Copyright 2009-2024 | Website Designed By   Insider Perks, Inc

Royal Caribbean shares huge onboard health and safety news

W hen you go to a hotel or a theme park and get infected with a virus, you don't know exactly what happened. Maybe you caught the virus at the airport, in a rest stop, on an airplane, or even at your hotel or in a restaurant.

That's generally because by the time you get sick, you're no longer at the place where you got infected. Cruise ships, however, lack the same plausible deniability, and historically viruses spread quickly on ships.

Related: Royal Caribbean bets big on new ships, private destinations

On a seven-day cruise, you might actually have picked up an illness at the supermarket or at work, but when you get sick on the ship, people blame the cruise line. When someone falls ill, cruise lines don't actually care where they got infected. They simply want to slow down the spread of the disease.

That has always been the case, but the Covid pandemic and the Centers for Disease Control (CDC) shutting down the cruise industry from the U.S. for over a year put shipboard illness under a bigger microscope. For months, the federal agency reported on onboard Covid levels and did little to share all of the steps the major cruise lines had taken to mitigate outbreaks.

Now, with Covid becoming less of a concern, Royal Caribbean has shared some big news about its efforts to control another virus, norovirus, which spreads quickly on ships. 

Royal Caribbean has made ships safer

"Norovirus is a very contagious virus that causes vomiting and diarrhea. Anyone can get infected and sick with norovirus. Norovirus is sometimes called the 'stomach flu' or 'stomach bug.' However, norovirus illness is not related to the flu, which is caused by influenza virus," according to the CDC.

The virus can cause problems on cruise ships, but it's actually a pretty rare occurrence.

"Norovirus is the most frequent (over 90%) cause of outbreaks of diarrheal disease on cruise ships and these outbreaks often get media attention, which is why some people call norovirus the 'cruise ship virus.' However, norovirus outbreaks on cruise ships account for only a small percentage (1%) of all reported norovirus outbreaks," the federal agency reported.

You are much more likely to get norovirus in a land-based restaurant or healthcare facility than on a cruise ship, but cruise outbreaks make for good stories and get widespread media attention.

Royal Caribbean began its Norovirus Eradication Campaign in 2023. It's a six-step program that has worked to stop outbreaks on its ships, the Royal Caribbean Blog reported.

Royal Caribbean's plan has worked

Royal Caribbean has enacted a comprehensive plan designed to contain norovirus and prevent its spread.

• Enhanced acute GI training for onboard medical teams and traveling doctors
• Increased doctor oversight of its Outbreak Prevention Plan, which covers requirements like hand washing, buffet oversight, and disinfectant mandates for all public areas aboard its ships.

Switching to PDI SaniCloth Prime hospital-grade disinfectant wipes, wipes certified to kill norovirus by the EPA.

New contactless tap technology, eliminating the need for crew to handle guest cards

Enhanced crew training on what to do when experiencing acute GI symptoms and how to avoid cross-contamination in food and beverage service areas

An update to Royal Caribbean's Safety & Quality Management system to stop self-service in buffets if the onboard norovirus rate exceeds 1.5%

"After the eradication campaign was implemented in June 2023, there was not a single norovirus outbreak onboard any Royal Caribbean International or Celebrity Cruise ship for the remainder of 2023," the report shared.

Celebrity Constellation, however, did have an outbreak in January 2024 that was listed on a CDC website, according to Royal Caribbean Blog.

• Election 2024
• Entertainment
• Newsletters
• Photography
• Personal Finance
• AP Investigations
• AP Buyline Personal Finance
• AP Buyline Shopping
• Press Releases
• Israel-Hamas War
• Russia-Ukraine War
• Global elections
• Asia Pacific
• Latin America
• Middle East
• Election Results
• Delegate Tracker
• AP & Elections
• Auto Racing
• 2024 Paris Olympic Games
• Movie reviews
• Book reviews
• Personal finance
• Financial Markets
• Business Highlights
• Financial wellness
• Artificial Intelligence
• Social Media

CDC is investigating gastrointestinal sickness on luxury cruise ship Queen Victoria

FILE - The Queen Victoria makes its way into Pier 35 in San Francisco on Jan. 27, 2010. The Centers for Disease Control and Prevention is investigating an outbreak on the luxury cruise ship where more than 150 people have reported gastrointestinal illness. The Queen Victoria departed San Francisco Wednesday, Feb. 7, 2024, on its way from Florida to Hawaii and is carrying 1,800 passengers and nearly 970 crew members. (AP Photo/Eric Risberg, File)

• Copy Link copied

SAN FRANCISCO (AP) — The Centers for Disease Control and Prevention is investigating an outbreak on a luxury cruise ship where more than 150 people have reported gastrointestinal illness, including diarrhea and vomiting.

The Queen Victoria, operated by Cunard Cruise Line, departed San Francisco Wednesday on its way from Florida to Hawaii. The ship is carrying 1,800 passengers and 970 crew members.

The cause is unknown. Cunard told the CDC that the ship increased cleaning and disinfection, and isolated ill passengers and crew.

The reported cases are totals for the entire voyage and do not represent how many people are actively sick at any one time, the CDC said.

The company did not immediately respond to an email from The Associated Press seeking more details.

The ship originated in Germany Jan. 9 and departed Florida Jan. 22, according to ship tracker Cruise Mapper. Its next stop is Honolulu, Hawaii, on Feb. 12 and ends in Australia next month.

An official website of the United States government

The .gov means it’s official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

• Publications
• Account settings

Preview improvements coming to the PMC website in October 2024. Learn More or Try it out now .

• Advanced Search
• Journal List
• MMWR Surveill Summ
• v.70(6); 2021 Sep 24

Acute Gastroenteritis on Cruise Ships — Maritime Illness Database and Reporting System, United States, 2006–2019

Keisha a. jenkins, george h. vaughan, jr., luis o. rodriguez, amy freeland, problem/condition.

Gastrointestinal illness is common worldwide and can be transmitted by an infected person or contaminated food, water, or environmental surfaces. Outbreaks of gastrointestinal illness commonly occur in crowded living accommodations or communities where persons are physically close. Pathogens that cause gastrointestinal illness outbreaks can spread quickly in closed and semienclosed environments, such as cruise ships. CDC’s Vessel Sanitation Program (VSP) is responsible for conducting public health inspections and monitoring acute gastroenteritis (AGE) illness on cruise ships entering the United States after visiting a foreign port.

Period Covered

2006–2019.

Description of System

VSP maintains the Maritime Illness Database and Reporting System (MIDRS) for monitoring cases of AGE illness among passengers and crew sailing on cruise ships carrying ≥13 passengers and within 15 days of arrival at U.S. ports from foreign ports of call. Cruise ships under VSP jurisdiction are required to submit a standardized report (24-hour report) of AGE case counts for passengers and crew 24–36 hours before arrival at the first U.S. port after traveling internationally. If the cumulative number of AGE cases increases after submission of the 24-hour report, an updated report must be submitted no less than 4 hours before the ship arrives at the U.S. port. A special report is submitted to MIDRS when vessels are within 15 days of arrival at a U.S. port and cumulative case counts reach 2% of the passenger or crew population during a voyage. VSP declares an outbreak when 3% or more of the passengers or crew on a voyage report AGE symptom to the ship’s medical staff.

During 2006–2019, a total of 37,276 voyage reports from 252 cruise ships were submitted to MIDRS. Of the 252 cruise ships, 80.6% were extra large in size (60,001–120,000 gross registered tons [GRT]), 37.0% and 32.9% had voyages lasting 3–5 days and 8–10 days, respectively, and 53.2% were traveling to a port in the Southeast region of the United States at the time the final MIDRS report was submitted. During 2006–2019, VSP received 18,040 (48.4%) 24-hour routine reports, 18,606 (49.9%) 4-hour update reports, and 612 (1.6%) special reports (2% and 3% AGE reports). Incidence rates decreased from 32.5 cases per 100,000 travel days to 16.9 for passengers and from 13.5 to 5.2 for crew. Among passengers, AGE incidence rates increased with increasing ship size and voyage length. For crew members, rates were significantly higher on extra-large ships (19.8 per 100,000 travel-days) compared with small and large ships and on voyages lasting 6–7 days. Geographically, passenger incidence rates were highest among ships underway to ports in California, Alaska, Texas, New York, Florida, and Louisiana. Among passengers, AGE incidence rates were significantly higher on ships anchoring in California (32.1 per 100,000 travel-days [95% confidence interval (CI) = 31.7–32.4]); among crew, they were significantly higher in the South region of the United States (25.9 [CI = 25.1–26.7]).

Interpretation

This report is the first detailed summary of surveillance data from MIDRS during 2006–2019. AGE incidence rates decreased during this time. Incidence rates among passengers were higher on mega and super-mega ships and voyages lasting >7 days. AGE incidence among crew was higher on extra-large ships and voyages lasting 6–7 days. Ship size and voyage length are associated with AGE incidence rates, and more targeted effort is needed to prevent disproportionate AGE incidence rates among passengers and crew sailing in high-risk situations.

Public Health Actions

Maritime AGE surveillance provides important information about the epidemiology of gastrointestinal illness among cruise ship populations traveling in U.S. jurisdictions. AGE illness is highly contagious and can be transmitted quickly within vessels. State and local public health departments in the United States can use data in this report to better inform the traveling public about the risk for AGE and the importance of their role in minimizing the risk for illness while traveling onboard cruise ships. Key elements for reducing exposure to AGE illness, limiting the spread of illness, and preventing AGE outbreaks are proper hand hygiene practices and prompt isolation of symptomatic persons. Passengers can work in collaboration with cruise lines to promote onboard public health by frequently washing their hands, promptly reporting AGE illness symptoms, and isolating themselves from other persons immediately after illness onset. Access to and proper use of handwashing stations can reduce the risk for illness transmission aboard cruise ships.

Introduction

Acute gastroenteritis (AGE) illnesses affect millions of persons worldwide ( 1 , 2 ) ( https://www.cdc.gov/norovirus/trends-outbreaks/worldwide.html ). The most common modes of transmission are through interaction with an infected person, consumption of contaminated food and water, and contact with contaminated environmental surfaces ( 1 , 2 ). Outbreaks of AGE illness commonly occur in crowded living accommodations or communities where persons are crowded together and can spread quickly in semienclosed environments, such as cruise ships. The Vessel Sanitation Program (VSP) is responsible for conducting environmental health inspections and monitoring the occurrence of AGE illness on cruise ships entering the United States from a foreign port.

Since 1975, VSP has worked collaboratively with the cruise ship industry to monitor AGE illness and minimize the risk for communicable diseases onboard cruise ships ( 3 ). In the early 1970s, cruise ships experienced an excessive number of gastrointestinal disease outbreaks, which led CDC to establish VSP in 1975 ( 4 ). The mission of VSP is to prevent and control the introduction, transmission, and spread of AGE illnesses on cruise ships to U.S. ports from cruise ships sailing from foreign ports. However, VSP does not monitor AGE illness on cargo ships and private yachts. VSP is authorized under the Public Health Service Act (42 U.S.C. Section 264 Quarantine and Inspection Regulations to Control Communicable Diseases ) to take necessary measures to prevent the introduction and transmission of communicable disease into the United States from a foreign country ( 5 ).

The two main operational components of VSP are unannounced environmental health ship inspections and surveillance and outbreak investigations of AGE. Federal regulation 42 (CFR Section 71.41 General Provisions, Foreign Quarantine Requirements Upon Arrival at U.S. Ports: Sanitary Inspections ) allows VSP to conduct unannounced ship inspections to identify the existence of pests, contaminated food or water, and other unsanitary conditions that could lead to the spread of communicable diseases ( 6 ).

VSP obtains its operating funds through user fees paid by the cruise lines after ships undergo unannounced environmental health inspections. Every ship under VSP jurisdiction is subject to twice-yearly inspections to ensure the ship maintains an appropriate level of sanitation ( 7 ). Cruise ship companies pay an inspection fee based on each ship’s gross registered tonnage (GRT) ( https://www.cdc.gov/nceh/vsp/desc/about_inspections.htm ). Inspection scores range from 0–100. An inspection score lower than 86 is considered unsatisfactory and subjects the ship to an unannounced reinspection.

VSP actively monitors the occurrence of AGE illness as directed by regulation 42 CFR Section 71.41(c), which specifies that the master of a ship carrying ≥13 passengers must report the number of AGE cases (including zero) among passengers and crew and record it in the ship’s medical log during the current cruise ( 7 ). Since April 1, 1975, VSP has maintained records of diarrheal illness for passenger ships visiting U.S. ports ( 4 ). Until 2001, ship masters reported the number of diarrheal illnesses by radio or telephone to CDC’s VSP 24 hours before arrival at a U.S. port. Ship masters no longer submit gastrointestinal illness (which includes diarrhea and other symptoms) reports by radio. Currently, illness counts are submitted by telephone, fax, or email or directly to the Maritime Illness Database and Reporting System (MIDRS).

This report uses MIDRS data to describe the incidence rates of AGE illness onboard passenger cruise ships that travel from foreign countries by ship size, voyage length, and regional U.S. ports of call for arrival. This is the first comprehensive summary of surveillance data to describe AGE incidence trends for cruise ships sailing in U.S. jurisdiction. State and local public health departments in the United States can use data in this report to better inform the traveling public about the risk for AGE and the importance of their role in minimizing the risk for illness while traveling onboard cruise ships.

VSP monitors cases of AGE illness among passengers and crew sailing on cruise ships carrying ≥13 passengers and within 15 days of arrival at a U.S. port from a foreign port of call. MIDRS was created in 2000 to allow submission of AGE reports to VSP through a web-based system. MIDRS is a syndromic surveillance system that collects cumulative case counts of passengers and crew reporting gastrointestinal symptoms to the ship medical staff during a single voyage. Each report submitted to MIDRS includes cruise ship name, voyage number, embarkation and disembarkation dates and locations, total number of passengers and crew, and number of passenger and crew that reported to the medical clinic with specific AGE symptoms (i.e., vomiting, diarrhea, abdominal cramps, headache, myalgia, or fever defined as ≥100.4°F [≥38°C]). AGE reports in MIDRS are submitted through the web-based portal system, email, fax, or phone call. Ships might submit multiple MIDRS reports per voyage, and each report is a cumulative count of ill passengers and crew that report to the medical center with AGE symptoms. Because final voyage case counts are not collected in MIDRS, data in this report were based on the last cumulative voyage report submitted to MIDRS. Although AGE outbreaks are stratified by passenger and crew, the occurrence of outbreaks is not mutually exclusive (i.e., not limited to a single population) for passengers and crew. The total number of AGE outbreaks will include overlap among these populations; however, for this report, outbreaks were categorized as passenger- or crew-associated outbreaks if >3% of the crew or passenger population reported AGE illness (VSP’s outbreak threshold).

MIDRS Reporting

Cruise ships under VSP jurisdiction are required to submit a standardized AGE report (24-hour report) of case counts for passengers and crew 24–36 hours before arrival at a U.S. port after traveling internationally. If the cumulative number of AGE cases changes after submission of the 24-hour report, a 4-hour update report must be submitted no less than 4 hours before the ship arrives at the U.S. port. For voyages lasting >15 days, reporting of cumulative AGE case counts is required for cases that occur 15 days before the expected arrival at a U.S. port. When vessels are within 15 days of arrival at a U.S. port and cumulative case counts reach 2% of the passenger or crew population, a special report is submitted to MIDRS, which initiates active monitoring of illness patterns onboard the ship. MIDRS data do not reflect final AGE case counts at the time of disembarkation because ships are not required to report final voyage case counts for passengers and crew. VSP defines an outbreak as a cumulative case count that meets or exceeds 3% of the passenger or crew population and, in response, VSP conducts a remote environmental and epidemiologic consultation or an onboard investigation when logistically feasible ( https://www.cdc.gov/nceh/vsp/desc/about_investigations.htm ).

Reportable Case Definition

In 1975, a reportable AGE case was limited to diarrheal illness defined as a person experiencing three or more watery stools in a 24-hour period. In 2000, the definition of a reportable AGE case was expanded to include a person who experienced three or more loose stools within a 24-hour period or vomiting plus one other symptom (i.e., diarrhea, abdominal cramps, headache, myalgia, or fever defined as ≥100.4°F [≥38°C]) in a 24-hour period. The revised case definition was first published in the 2000 VSP Operations Manual and became fully operational in 2001 ( 8 ). In 2011, VSP modified the definition of a reportable AGE case to include the frequency of diarrheal episodes “above normal for the individual” to be consistent with the World Health Organization’s definition of diarrhea ( 9 ) ( https://www.who.int/news-room/fact-sheets/detail/diarrhoeal-disease ).

Data Analysis

The period covered in this surveillance analysis began in 2006 because it was the first year cruise ships were required to provide a unique voyage number, which provided the ability to differentiate multiple voyage reports submitted by the same ship each year. This analysis includes all AGE case reports submitted to VSP during 2006–2019 from cruise ships carrying ≥13 passengers and entering the United States from foreign ports of call. AGE incidence rates per 100,000 travel days and trends were examined for various cruise ship and voyage characteristics, including ship size (GRT), voyage length (days), and regional port it was traveling to at the time the MIDRS report was submitted (grouped into seven regions defined by VSP). Categorization of ship size was based on VSP’s categories used for the program’s construction and inspection activities: extra small, small, and medium (≤30,000 GRT), large (30,001–60,000 GRT), extra large (60,001–120,000 GRT), mega (120,001–140,000 GRT), and super mega (>140,001 GRT). Voyage length was categorized to match cruise line marketing travel packages: 3–5 days, 6–7 days, 8–10 days, and 11–14 days. This report excludes voyages lasting <3 days and >21 days, and vessels that carried <100 passengers. Regional ports and regions were categorized as follows: Northwest (Washington, Oregon, and Alaska), Hawaiian Islands and Guam, California, South (all ports on the Gulf of Mexico excluding Florida), Northeast (all states north of and including North Carolina), Southeast (all Atlantic ports in Florida, Georgia, and South Carolina), and Caribbean Islands. Poisson regression was used to examine rates, with travel days as an offset variable, and rate trends, with calendar year as the predictor variable. Wald chi-square was used to assess the association between variables, with the significance threshold set at 0.05. Rates and incidence trends were examined by traveler type (passenger and crew) and cruise ship characteristics (ship size based on GRT and voyage length in days). Reference groups for comparing incidence rates were based on cruise ship characteristic categories with the largest total population. Regional AGE incidence rates were mapped using natural breaks as cut points, and port-specific AGE incidence rates (total population, passengers, and crew) were mapped using quartile breaks as cut points to examine the variability around the median rate. Ports with <20 reports were considered unstable, and no data are presented. All statistical analyses were conducted using SAS software (version 9.4; SAS Institute).

During 2006–2019, a total of 37,258 AGE surveillance reports were obtained from 252 cruise ships arriving at U.S. ports ( Table 1 ). Among the reports received, 48.4% (n = 18,040) were 24-hour reports, 49.9% (n = 18,606) were 4-hour reports, and 1.6% (n = 612) were special reports. Of the 252 cruise ships, 80.6% were extra large. Approximately 37.0% had voyages lasting 3–5 days and 32.9% had voyages lasting 8–10 days. The majority of the cruise ships (53.2%) were traveling to a port in the Southeast region at the time the report was submitted.

* Cruise ships carrying 13 passengers and within 15 days of arrival at a U.S. port from a foreign port of call.

† Sum might not total 100% because of rounding.

§ 24-hour report = case counts for passengers and crew 24–36 hours before arrival at a U.S. port; 4-hour report = changes in cumulative case counts since submission of the 24-hour report must be submitted no less than 4 hours before the ship arrives at U.S. port; Special report = cumulative AGE case counts ≥2% of passengers or crew.

¶ Categorization of ship size is based on Vessel Sanitation Program (VSP) categories used by VSP for the program’s construction and inspection activities, and voyage length is categorized to match cruise line marketing travel packages.

** Northwest (WA, OR, AK): ADK, AKU, ANC, AOR, ATT, BAK, BWA, COR, DHA, EFC, FHW, GLB, HAK, HNS, HOM, IAK, JNU, KIS, KOD, KTN, MET, NOM, PAN, POR, PTB, SEA, SGY, SIT, SWD, VDZ, WAI, WRG, WTR, YAK; Hawaiian Islands, Guam, American Samoa, Saipan : GUA, HIL, HNL, KAH, KAU, KON, LAH, MAU, PAS, SAI, SAM; California : ACA, CAT, LAX, LBC, MCA, SAC, SBC, SDC, SFO, SPC; South (all ports on Gulf of Mexico, excluding FL): BRT, CCT, FTP, FTX, GAL, GMS, HOU, MAL, NOL, PAT, PIT; Northeast (all states north of and including NC): ABN, AMD, ANY, AVA, BAL, BAR, BAT, BNJ, BNY, BOO, BOS, BUF, CHI, CLY, CMA, CME, COH, DET, DMN, EME, ERI, GMA, GNY, HOL, JOL, KNY, MAC, MAR, MCI, MIL, MVY, NOR, NRI, NYC, OGS, OMA, OSW, PEJ, PHL, PHM, PME, PNH, PNY, PRI, PVM, RCK, RHI, RNY, SMA, SMI, STP, SYN, TCM, TNY, TRA, WDE, WNC, WPN, WRI, WVA, WYN, YRK; Southeast (all ports in FL, GA, and SC): CHA, JAX, KWE, MAN, MIA, NPF, PBF, PCF, PEN, PEV, SAV, SFL, SPF, TAM, VBF, WPB; Caribbean Islands : FPR, ISC, MAY, NYA, PPR, SJO, SJU, STC, STT.

During 2006–2019, incidence rates decreased significantly, from 32.5 cases per 100,000 travel days to 16.9 cases among passengers, and from 13.5 to 5.2 among crew ( Figure 1 ). Among passengers, AGE incidence rates increased significantly with increasing ship size and voyages lasting more than 7 days, whereas for crew members, rates were significantly higher for mega (26.7 per 100,000 travel-days) and super-mega (29.2 per 100,000 travel days) ships compared with the smaller ship sizes and voyages > 5 days compared with 3–5 day voyages ( Table 2 ). Among crew, incidence rates were significantly higher for extra-large ships compared with other ship sizes and voyages lasting 6–7 days. Compared with rates on ships traveling to ports in the Southeast region, AGE incidence rates were higher on ships traveling to a port in California (32.0 per 100,00 travel days) or the South (23.7) among passengers and crew (24.8 and 25.9, respectively).

Incidence rate* of acute gastroenteritis on cruise ships, by year and traveler type — Maritime Illness Database and Reporting System, United States, 2006––2019 †

* Per 100,000 travel days (defined as the sum of passengers/crew cases of the total number of voyage days). Rate = [(Total number of passenger/crew cases) / (total passengers/crew onboard x total number of voyage days during a voyage)] x 100,000 travel days.

† Case counts are based on the last report submitted to Maritime Illness Database Reporting System and do not reflect final counts at the time of disembarkation; excludes ships with voyage length <3 and >21 days and <100 passengers or no crew.

Abbreviations: CI = confidence interval; Ref = referent.

* [(Total no. passenger/crew cases) / (total passengers/crew onboard x total number of voyage days during a voyage)] x 100,000 travel days.

† Wald chi-square was used to assess the association between variables, with the significance threshold set at 0.05.

§ Categorization of ship size is based on Vessel Sanitation Program (VSP) categories used by VSP for the program’s construction and inspection activities, and voyage length is categorized to match cruise line marketing travel packages.

¶ Northwest (WA, OR, AK): ADK, AKU, ANC, AOR, ATT, BAK, BWA, COR, DHA, EFC, FHW, GLB, HAK, HNS, HOM, IAK, JNU, KIS, KOD, KTN, MET, NOM, PAN, POR, PTB, SEA, SGY, SIT, SWD, VDZ, WAI, WRG, WTR, YAK; Hawaiian Islands, Guam, American Samoa, Saipan : GUA, HIL, HNL, KAH, KAU, KON, LAH, MAU, PAS, SAI, SAM; California : ACA, CAT, LAX, LBC, MCA, SAC, SBC, SDC, SFO, SPC; South (all ports on Gulf of Mexico, excluding FL): BRT, CCT, FTP, FTX, GAL, GMS, HOU, MAL, NOL, PAT, PIT; Northeast (all states north of and including NC): ABN, AMD, ANY, AVA, BAL, BAR, BAT, BNJ, BNY, BOO, BOS, BUF, CHI, CLY, CMA, CME, COH, DET, DMN, EME, ERI, GMA, GNY, HOL, JOL, KNY, MAC, MAR, MCI, MIL, MVY, NOR, NRI, NYC, OGS, OMA, OSW, PEJ, PHL, PHM, PME, PNH, PNY, PRI, PVM, RCK, RHI, RNY, SMA, SMI, STP, SYN, TCM, TNY, TRA, WDE, WNC, WPN, WRI, WVA, WYN, YRK; Southeast (all ports in FL, GA, and SC): CHA, JAX, KWE, MAN, MIA, NPF, PBF, PCF, PEN, PEV, SAV, SFL, SPF, TAM, VBF, WPB; Caribbean Islands : FPR, ISC, MAY, NYA, PPR, SJO, SJU, STC, STT.

Overall, AGE incidence rates were highest among cruise ships visiting ports in California (San Diego, Los Angeles, San Pedro, and San Francisco), Alaska (Whittier and Seward), Texas (Houston and Galveston), New York (Brooklyn and New York City), Florida (Fort Lauderdale), and Louisiana (New Orleans) ( Figure 2 ). Among passengers, AGE incidence rates were in the highest quartile for ships anchoring in California (32.1 per 100,000 travel days) ( Figure 3 ); for crew, rates were in the highest quartile for ships anchoring in the South region (25.9) ( Figure 4 ). The length of cruise ship voyages varied greatly depending on the regional port to which ships were traveling. The majority of ships traveling to ports in California and the Southeast region were on voyages lasting 3–5 days (52% and 51.9%, respectively); 6–7 days for ships anchoring in the South region (47.0%); 8–10 days for ships visiting ports in the Northwest (88.8%), Caribbean Islands (70.1%), and Northeast (68.7%) regions; and 11–21 days for ports in the Hawaiian Islands (97.0%) ( Figure 5 ).

Incidence rate* of acute gastroenteritis reported by cruise ships anchoring at U.S. ports, † — Maritime Illness Database and Reporting System, United States, 2006–2019

* Per 100,000 travel days (defined as the sum of passengers/crew cases of the total number of voyage days). Rate = [(Total number of passenger/crew cases) / (total passengers/crew onboard x total number of voyage days during a voyage)] x 100,000 travel days. Rates (total population, passengers, and crew) were mapped using quartile breaks as cut points to measure the variability around the median rate. Ports with <20 reports were considered unstable and no data are presented.

† Northwest (WA, OR, AK): ADK, AKU, ANC, AOR, ATT, BAK, BWA, COR, DHA, EFC, FHW, GLB, HAK, HNS, HOM, IAK, JNU, KIS, KOD, KTN, MET, NOM, PAN, POR, PTB, SEA, SGY, SIT, SWD, VDZ, WAI, WRG, WTR, YAK. Hawaiian Islands, Guam, American Samoa, Saipan: GUA, HIL, HNL, KAH, KAU, KON, LAH, MAU, PAS, SAI, SAM. California: ACA, CAT, LAX, LBC, MCA, SAC, SBC, SDC, SFO, SPC. South (all ports on Gulf of Mexico, excluding FL): BRT, CCT, FTP, FTX, GAL, GMS, HOU, MAL, NOL, PAT, PIT. Northeast (all states north of and including NC): ABN, AMD, ANY, AVA, BAL, BAR, BAT, BNJ, BNY, BOO, BOS, BUF, CHI, CLY, CMA, CME, COH, DET, DMN, EME, ERI, GMA, GNY, HOL, JOL, KNY, MAC, MAR, MCI, MIL, MVY, NOR, NRI, NYC, OGS, OMA, OSW, PEJ, PHL, PHM, PME, PNH, PNY, PRI, PVM, RCK, RHI, RNY, SMA, SMI, STP, SYN, TCM, TNY, TRA, WDE, WNC, WPN, WRI, WVA, WYN, YRK. Southeast (all ports in FL, GA, and SC): CHA, JAX, KWE, MAN, MIA, NPF, PBF, PCF, PEN, PEV, SAV, SFL, SPF, TAM, VBF, WPB. Caribbean Islands: FPR, ISC, MAY, NYA, PPR, SJO, SJU, STC, STT.

Incidence rate* of acute gastroenteritis among passengers, by U.S. regional port location, † — Maritime Illness Database and Reporting System, United States, 2006–2019

Incidence rate* of acute gastroenteritis among crew members, by U.S. regional port location,† — Maritime Illness Database and Reporting System, United States, 2006–2019

Percentage of acute gastroenteritis reports submitted, by regional port* and voyage length † — Maritime Illness Database and Reporting System, United States, 2006–2019

* Northwest (WA, OR, AK): ADK, AKU, ANC, AOR, ATT, BAK, BWA, COR, DHA, EFC, FHW, GLB, HAK, HNS, HOM, IAK, JNU, KIS, KOD, KTN, MET, NOM, PAN, POR, PTB, SEA, SGY, SIT, SWD, VDZ, WAI, WRG, WTR, YAK. Hawaiian Islands, Guam, American Samoa, Saipan: GUA, HIL, HNL, KAH, KAU, KON, LAH, MAU, PAS, SAI, SAM. California: ACA, CAT, LAX, LBC, MCA, SAC, SBC, SDC, SFO, SPC. South (all ports on Gulf of Mexico, excluding FL): BRT, CCT, FTP, FTX, GAL, GMS, HOU, MAL, NOL, PAT, PIT. Northeast (all states north of and including NC): ABN, AMD, ANY, AVA, BAL, BAR, BAT, BNJ, BNY, BOO, BOS, BUF, CHI, CLY, CMA, CME, COH, DET, DMN, EME, ERI, GMA, GNY, HOL, JOL, KNY, MAC, MAR, MCI, MIL, MVY, NOR, NRI, NYC, OGS, OMA, OSW, PEJ, PHL, PHM, PME, PNH, PNY, PRI, PVM, RCK, RHI, RNY, SMA, SMI, STP, SYN, TCM, TNY, TRA, WDE, WNC, WPN, WRI, WVA, WYN, YRK. Southeast (all ports in FL, GA, and SC): CHA, JAX, KWE, MAN, MIA, NPF, PBF, PCF, PEN, PEV, SAV, SFL, SPF, TAM, VBF, WPB. Caribbean Islands: FPR, ISC, MAY, NYA, PPR, SJO, SJU, STC, STT.

† Voyage length is categorized to match cruise line marketing travel packages. Cruise ships sailing to Hawaiian islands are not represented in voyages of <8 days.

AGE incidence rate trends for passengers and crew were analyzed in relation to ship size and, during 2006–2019, rates showed a decreasing trend among extra-large, mega, and super-mega ships. Among passengers, AGE illness incidence rates peaked in 2010 and 2014 for mega ships, during 2011 and 2012 for super-mega ships, and in 2013 for small ships (≤30,000 GRT) ( Figure 6 ). AGE incidence rates among crew increased in 2010, 2013, and 2016 for all ship sizes ( Figure 7 ). Among passengers, rates remained relatively stable for voyages lasting <11 days. During 2006–2019, rates declined for voyages of 11–14 days and 15–21 days but remained higher than rates for voyages <11 days. Incidence rates spiked among passengers traveling on voyages lasting ≥6 days in 2007 and ≥11 days in 2010 ( Figure 8 ). Among crew, annual incidence rates remained relatively stable regardless of voyage length, although in 2014 there was a slight increase in rates among cruise ships on voyages of 15–21 days ( Figure 9 ).

Incidence rate* of acute gastroenteritis among passengers, by ship size † and year — Maritime Illness Database and Reporting System, United States, 2006–2019

Abbreviation: GRT = gross registered tons.

† Categorization of ship size is based on the Vessel Sanitation Program categories used for the program’s construction and inspection activities.

Incidence rate* of acute gastroenteritis among crew, by ship size † and year — Maritime Illness Database and Reporting System, United States, 2006–2019

Incidence rate* of acute gastroenteritis among passengers, by voyage length † and year — Maritime Illness Database and Reporting System, United States, 2006–2019

† Voyage length is categorized to match cruise line marketing travel packages.

Incidence rate* of acute gastroenteritis among crew, by voyage length † and year — Maritime Illness Database and Reporting System, United States, 2006–2019

During 2006–2019, VSP investigated 156 outbreaks among passengers and 16 outbreaks among crew. Of the 156 passenger-associated outbreaks, 63% occurred during 2006–2012; for crew, 50% occurred during 2014–2019 ( Figure 10 ). A total of 117 (75%) outbreaks occurred among passengers on voyages lasting 11–21 days; for crew, 10 (63%) of 16 outbreaks occurred on voyages lasting 3–7 days ( Table 3 ). A spatial cluster of 13 (81.3%) AGE outbreaks among crew was identified for cruise ships arriving at ports in the southeastern region. A total of 122 passenger outbreaks occurred on cruise ships visiting ports in the Southeast (44.3%), California (20.1%), and Northeast (17.5%) regions ( Table 3 ).

Percentage of acute gastroenteritis outbreaks among passengers and crew, by year — Maritime Illness Database and Reporting System, United States, 2006–2019*

* During 2006–2019, VSP investigated 156 outbreaks among passengers and 16 outbreaks among crew.

* For passengers, N = 156; for crew, N = 16. Percentages might not total 100% because of rounding.

§ Northwest (WA, OR, AK): ADK, AKU, ANC, AOR, ATT, BAK, BWA, COR, DHA, EFC, FHW, GLB, HAK, HNS, HOM, IAK, JNU, KIS, KOD, KTN, MET, NOM, PAN, POR, PTB, SEA, SGY, SIT, SWD, VDZ, WAI, WRG, WTR, YAK; Hawaiian Islands, Guam, American Samoa, Saipan : GUA, HIL, HNL, KAH, KAU, KON, LAH, MAU, PAS, SAI, SAM; California : ACA, CAT, LAX, LBC, MCA, SAC, SBC, SDC, SFO, SPC; South (all ports on Gulf of Mexico, excluding FL): BRT, CCT, FTP, FTX, GAL, GMS, HOU, MAL, NOL, PAT, PIT; Northeast (all states north of and including NC): ABN, AMD, ANY, AVA, BAL, BAR, BAT, BNJ, BNY, BOO, BOS, BUF, CHI, CLY, CMA, CME, COH, DET, DMN, EME, ERI, GMA, GNY, HOL, JOL, KNY, MAC, MAR, MCI, MIL, MVY, NOR, NRI, NYC, OGS, OMA, OSW, PEJ, PHL, PHM, PME, PNH, PNY, PRI, PVM, RCK, RHI, RNY, SMA, SMI, STP, SYN, TCM, TNY, TRA, WDE, WNC, WPN, WRI, WVA, WYN, YRK; Southeast (all ports in FL, GA, and SC): CHA, JAX, KWE, MAN, MIA, NPF, PBF, PCF, PEN, PEV, SAV, SFL, SPF, TAM, VBF, WPB; Caribbean Islands : FPR, ISC, MAY, NYA, PPR, SJO, SJU, STC, STT.

The incidence of reported AGE cases on cruise ships has declined over time, with higher rates observed among passengers compared with crew. The decline in AGE incidence rates might in part be associated with the evolution of environmental health sanitation standards that were established in 1975 by CDC and enforced during environmental health ship inspections conducted by VSP environmental health officers ( 10 ). Ship inspections were implemented in 1975 to ensure a higher level of shipboard sanitation to protect the health of the travelling public, including crew members who typically spend several months at a time onboard a cruise ship. In addition to implementation of ship inspections, cruise ship industry practices, such as hygiene standards, availability of hand hygiene stations in public areas throughout the ship, and health screening of passengers and crew before embarkation, also have likely contributed to the trend of declining AGE incidence rates. AGE incidence rates among passengers traveling on super-mega ships spiked in 2011. This finding might be attributed to changes in the AGE case definition. In 2011, the case definition was broadened to include the frequency of diarrheal episodes “above normal for the individual” to allow detection of “true” AGE cases as knowledge increased ( 9 ) ( https://www.who.int/news-room/fact-sheets/detail/diarrhoeal-disease ). Therefore, these changes should be considered when making inferences on AGE incidence rates during this time.

Variation in incidence rates and outbreaks between passengers and crew can be explained by differences in exposure sources and adherence to outbreak management plans. Norovirus is the leading cause of AGE and causes a substantial burden on cruise ships. In 2002, the number of norovirus illness outbreaks increased substantially both on cruise ships and on land ( 11 ) and, since 2006, approximately 90% of cruise ship outbreaks with known causative agents involved noroviruses ( 12 ). Norovirus is highly contagious and requires only a small inoculum to produce infection (<100 viral particles) ( 13 ). The predominant mode of transmission for norovirus is the fecal-oral route; however, it also can easily be transmitted by an infected person, including those without symptoms, through contaminated food, water, or environmental surfaces ( 13 , 14 ). Pathogens (i.e., norovirus) can be introduced into the cruise ship environment by ill passengers during embarkation ( 14 , 15 ); however, person-to-person transmission via ill cabin mates and public vomiting incidents contribute to the occurrence of most of the outbreaks among passengers ( 16 ). Although cruise ship outbreaks were described separately for passengers and crew, voyage outbreaks occur simultaneously among passengers and crew during a voyage and are not limited to a single population. Passenger- and crew-associated outbreaks were based on the outbreak threshold; thus, if ≥3% of passenger or crew populations experienced AGE symptoms at a given time, outbreaks were categorized as a passenger-associated outbreak or crew-associated outbreak.

Lower AGE incidence rates among crew compared with passengers might be a result of differences in exposure sources. Residential accommodations and life on cruise ships for crew are different from passengers because they maintain separate living, dining, and recreational facilities onboard the ship and have different embarkation and disembarkation areas. Many crew positions do not require direct contact with passengers. As a result, many crew members have limited interaction with passengers by using only crew designated areas and interact with the same crew members for the length of their contracts. In addition, cruise companies have more control over crew to enforce adherence to public health measures and policies for preventing and mitigating AGE transmission, such as proper/frequent handwashing, prompt reporting of AGE symptoms, and adherence to isolation policies. For example, crew are required to promptly report illness at the time of onset and follow isolation procedures or face disciplinary actions for violating illness prevention and control guidelines. For passengers, cruise ship personnel have less authority to enforce adherence to illness prevention and control guidelines. As a result, nonreporting or delayed reporting of illness and noncompliance with isolation instructions among passengers is an ongoing problem that increases the risks for illness transmission and outbreaks.

The findings in this report indicate that incidence rates varied by ship size, voyage length, and regional port location. Overall, higher rates were associated with increasing ship size. Each year, new cruise ships are built to accommodate the growing number of cruisers ( 17 ). Since 1995, VSP has published public health guidelines for the construction and design of new and renovated cruise ships to promote uniform construction standards to meet sanitary criteria and limit the introduction and transmission of communicable diseases ( https://www.cdc.gov/nceh/vsp/docs/vsp_construction_guidelines_2018-508.pdf ). In addition, VSP partners with shipyards and vessel owners during plan reviews, consultations, and construction inspections to ensure public health safety and limit the introduction and transmission of communicable diseases onboard densely populated passenger cruise ships. The findings in this report also indicate that AGE incidence rates are higher on cruises lasting >7 days and that rates vary by regional port location. This report documents higher rates on cruise ships traveling to ports in California and lower rates in the Northwest region, whereas results in a previous study indicate rates to be highest in the Northwest region and lowest in the Northeast ( 18 ). Differences in findings might be due to the time frame in which the studies were conducted and correlation with the emergence of new norovirus strains ( 14 , 19 ). When stratified by voyage length, a greater percentage of cruise ships anchoring in California had voyages lasting 3–5 days. Voyages lasting 3–7 days result in high turnover of passengers, leading to a greater opportunity to expose crew to ill passengers, especially in regions where prevalence of illness is high. In addition to higher rates, these findings also indicate that AGE outbreaks are more frequent on voyages lasting >7 days among passengers and 6–7 days among crew. Voyages lasting >7 days present greater opportunity for person-to-person transmission because of extended time in a semienclosed environment. Prompt reporting of AGE symptoms is optimal for preventing outbreaks. In 2017, U.S. passengers accounted for 46% of global cruise ship travelers (26.8 million passengers), and the number of transit passengers visiting U.S. ports increased by 8% from 2016 to 2017 (5.6 million passengers) ( 20 ). With millions of passengers visiting U.S. ports, delayed reporting of AGE symptoms by passengers also could affect the health of shoreside communities and residents.

Limitations

The findings in this report are subject to at least four limitations. First, incidence rates should be interpreted as an underestimation of actual maritime AGE incidence rates because final AGE case counts for voyages that did not meet or exceed the outbreak threshold are not reported to VSP, voyages lasting >15 days are not required to report cases that occurred prior to 15 days of arrival to the United States, and cases are not reported if persons did not seek medical care onboard the ship. Second, the estimated incidence for voyages lasting 3–7 days might be biased because exposure to norovirus on these shorter voyages might result in symptoms occurring after the voyage has ended, leading to underreporting of AGE cases. Third, findings might be affected by reporting bias because not all symptomatic passengers report their symptoms to the medical center, and diagnoses of symptomatic cases are not validated with medical records or laboratory findings. In addition, standardized procedures are needed to retract reports sent incorrectly or with erroneous case counts; however, ongoing procedures are used to ensure information is as accurate as possible. For example, limited error checking is embedded in the web-based portal to MIDRS to validate case counts for passengers and crew to minimize reporting errors. Finally, the case definition for AGE illness was broadened in 2011 with the goal of identifying additional cases of AGE so cruise ship medical crew could treat, isolate, and monitor persons who are at risk for exposing others, thus limiting the spread of illness onboard ships. The case definition change in 2011 caused a spike in incidence rates and might have captured other illnesses.

Future Directions

This report examines the incidence of maritime AGE by cruise ship demographics and voyage characteristics. Accurate health monitoring of shipboard populations and improving incidence estimates rely on precise reporting of AGE cases. MIDRS data do not represent final AGE case counts at the time of disembarkation. Final voyage AGE case counts are not required to be reported to MIDRS, likely leading to an underestimation of the actual incidence of AGE illness and limiting accurate trend analysis, which can hamper efforts to improve public health interventions and policies to reduce disease transmission. Strengthening surveillance of AGE incidence would require both changes in AGE case count reporting policies and cruise ships to submit an end-of-voyage AGE case report.

Examination of voyage itineraries and land-based activities might be helpful to better understand disproportionate rates of AGE illness across U.S. regional ports. Additional research and evaluation are needed to determine possible causal relations between delayed reporting of AGE illness to ship medical personnel and demographic characteristics of traveling passengers. Another area for continued work includes cruise ship companies establishing new methods for prompt identification of ill passengers who do not report AGE symptoms or comply with isolation instructions during the infectious period.

Millions of passengers travel on cruise ships from U.S. ports every year. Since 1975, VSP has monitored AGE illness and conducted environmental health sanitation inspections of hundreds of cruise ship voyages each year. Ongoing public health prevention efforts to identify and eliminate risks for AGE illness associated with environmental contamination, person-to-person, and food and waterborne pathogen transmission are essential for reducing AGE incidence rates among passengers and crew. Continued surveillance provides an opportunity for VSP to work collaboratively with cruise lines to reduce the risk for AGE transmission onboard and mitigate possible transmission to local communities.

Promotion of proper handwashing practices is an effective strategy for preventing AGE outbreaks ( 21 ). Cruise ship travelers should adhere to recommendations for handwashing and sanitation during cruise ship travel and promptly report gastrointestinal illness symptoms to medical personnel (including mild symptoms) and follow isolation instructions. Federal and state programs to reduce the incidence of AGE illness in communities across the United States should consider innovative messaging for informing travelers about the risk for AGE and the importance of their role in minimizing their risk for illness while traveling onboard passenger cruise ships, especially for persons who are most vulnerable to infection. Health care providers should consider discussing the importance of good personal hygiene and proper handwashing during clinical examinations with patients, especially those planning to take a cruise.

Acknowledgements

The authors acknowledge David Olson (National Center for Environmental Health) for statistical guidance and support; and Claudio Owusu (Geospatial Research, Analysis, and Services Program, a division of the Agency for Toxic Substance and Disease Registry) for assistance with geospatial analysis.

Conflict of Interest: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. No potential conflicts of interest were reported.

How common is norovirus on cruise ships? Here’s why you shouldn’t worry

What's sneaky, super contagious and bound to cause diarrhea and vomiting? If you answered "norovirus," you'd be correct. But what is it, and why is it often associated with cruises?

An excessive number of news reports exist for norovirus cases on ships, making it seem to the unsuspecting public that cruise vessels are dirty or you're likely to get sick if you sail . I'm here to set the record straight.

Find out why norovirus is unfairly labeled a cruise ship illness, what cruise lines do to minimize onboard spread and whether you should be worried about it on your next voyage.

For more cruise news, guides and tips, sign up for TPG's cruise newsletter .

What is cruise ship norovirus?

Norovirus is the most common of several viruses that cause severe gastrointestinal illness or acute gastroenteritis. Symptoms may include diarrhea and vomiting, as well as abdominal cramping, headaches, muscle aches and fever — an unpleasant experience any time but especially when you're on vacation.

Norovirus is highly contagious and spreads when you touch a contaminated surface and then put your fingers in or near your mouth, such as when eating without washing your hands. It's also frequently spread through contaminated food, sometimes earning it the nickname "food poisoning," even though there are many pathogens that can cause foodborne illnesses. You might also hear it generically called a stomach bug or the stomach flu despite the fact that noroviruses are not the same as flu viruses.

How does norovirus spread on cruise ships?

What causes norovirus on cruise ships, anyway? Norovirus spreads easily in close quarters, such as those found on cruise ships. Although it can spread from person-to-person contact, on vessels, it's most commonly passed when passengers fail to wash their hands after coming in contact with high-touch areas, such as handrails, elevator buttons and serving utensils in the onboard buffets.

Infected passengers who don't wash their hands after coughing, sneezing or using the restroom are the reason those surfaces become contaminated in the first place. To avoid both spreading your own germs and picking up the germs of others, wash your hands frequently, especially before eating, for at least 20 seconds with soap and warm water, making sure to scrub around your fingernails and between your fingers.

Contaminated food is also a cause, but it's not as common on ships, where the staff is meticulously trained to follow health and safety guidelines for sanitation. Standards are enforced by the U.S. Centers for Disease Control and Prevention. (See the next section for more.)

What do cruise ships do to prevent norovirus outbreaks on board?

Cruise lines employ crews dedicated to keeping public areas and high-touch surfaces clean. Galley crews and waiters receive extensive training on food safety and handling.

Lines also screen passengers for signs of illness at embarkation. They ask passengers who feel ill during their cruises to report symptoms to the medical center and keep themselves isolated in their cabins.

On ships where outbreaks occur, the crew conducts a deep cleaning of the ship after passengers have disembarked and before the next sailing begins. In cases where outbreaks are particularly severe, subsequent sailings could be canceled to allow for more thorough sanitization.

Additionally, the CDC's Vessel Sanitation Program, implemented in the 1970s, subjects all passenger ships carrying 13 or more people to random, unannounced inspections if they wish to call on ports in the United States.

As part of the program, ships are required to adhere to stringent health and safety protocols that dictate everything from the cleaning of high-touch areas to how food is stored in freezers, refrigerators and galleys.

VSP inspectors board ships and conduct thorough checks to ensure compliance, and the standards are high. A score of less than 86 out of 100 is considered failing. You can find a list of the most recent inspection scores and lists of violations for each ship on the VSP website .

Should you worry about getting norovirus on a cruise?

The short answer is no. "People often associate cruise ships with acute gastrointestinal illnesses, such as norovirus, but acute gastrointestinal illness is relatively infrequent on cruise ships," the CDC says on its " Facts About Noroviruses on Cruise Ships " page.

Based on the math, you have less chance of catching a gastrointestinal illness on a ship than at many places you're likely to visit on land.

The CDC estimates only about 1% of all annual U.S. norovirus cases happen on cruise ships. The numbers are greatest in nursing homes, hospitals, schools and restaurants, which collectively account for about 91% of cases.

In a study of acute gastroenteritis cases from 2006 to 2019 (before the cruise industry's COVID-19 shutdown), the CDC found that the number of cases on ships decreased over those 14 years. It also noted that the number of cases tends to be higher on larger ships and on voyages of a week or longer.

"The rate of … illness on cruise ships decreased during 2006-2019 for passengers and crew," the report says. That's good news for cruisers.

During that time frame, approximately 127 million passengers sailed on the 252 cruise ships under VSP jurisdiction. Of those 127 million cruisers, 26,450 reported symptoms of gastrointestinal illness while on board. It sounds like a large number, but it amounts to just 0.02% (two one-hundredths of one percent) of cruisers throughout those 14 years, with the total number of cases decreasing from 4,507 in 2006 to 1,201 in 2019.

If you'd like to check out the outbreak information, you can find a detailed list of ships that have had acute gastroenteritis outbreaks (many of which were caused by norovirus), listed by year, about halfway down the CDC's outbreak page .

For more details on how to keep yourself healthy on board, visit TPG's story on how to avoid getting sick on a cruise .

Why are there so many cruise norovirus reports on the news?

The simple answer is that cruise ships are required to report cases of acute gastroenteritis to the CDC, even when the numbers are low. In contrast, other entities — schools, nursing homes, hospitals and restaurants — are not.

"Health officials track illness on cruise ships. So outbreaks are found and reported more quickly on a cruise ship than on land," reads the CDC's facts page .

Specifically, the medical staff from each cruise ship must submit a report with the number of ill passengers within 24 to 36 hours of its arrival at a U.S. port from a foreign port, even when no cases of gastrointestinal illness are present. They must also submit reports if 2% or more of the passengers and crew become ill and the ship is scheduled to visit a U.S. port within 15 days. If the number hits 3% or more, cases must be reported to the CDC even if the ship is not scheduled to call on a U.S. port within the next 15 days.

That means data for norovirus on cruise ships is more readily available than for other entities. It's easy to make norovirus case numbers sound alarming, but context matters. For example, 100 cases on a single ship might seem like a lot, but on a vessel like Oasis of the Seas, which carries more than 5,400 passengers, 100 cases are only about 2% of the onboard population.

Bottom line

Should you be worried about catching norovirus or another gastrointestinal illness when you cruise? The CDC says cruises account for some of the lowest case numbers in the U.S. annually.

Your chances of finding yourself confined to your room and hunched over a toilet for a week are slim when you sail, especially if you take common-sense precautions like washing your hands and not sharing drinks, utensils and other items that easily spread germs.

Have more cruise questions? TPG has answers:

• Are cruises safe? Here's what you need to know before you sail
• Packing for a cruise? These items aren't allowed on board
• Man overboard: Cruise ship overboards and how they happen
• What is baked Alaska, and why is it paraded around cruise ships?
• What are the largest cruise ships in the world?
• Gentlemen hosts: These men cruise to make sure single ladies have a great time
• What is the Jones Act and how does it affect cruise ships?
• What is a lido deck on a cruise ship?
• What's a cruise cabin guarantee and will it save you money?
• What's the difference between a cruise ship concierge and a butler?

Gastroenteritis outbreaks on cruise ships: contributing factors and thresholds for early outbreak detection

Affiliations.

• 1 Department of Hygiene and Epidemiology, Faculty of Medicine, University of Thessaly, Larissa, Greece.
• 2 Celestyal Cruises, Piraeus, Greece.
• 3 Robert Koch Institute, Berlin, Germany.
• 4 The members of the group are listed at the end of the article.
• PMID: 29162205
• PMCID: PMC5718393
• DOI: 10.2807/1560-7917.ES.2017.22.45.16-00576

When an increased number of acute gastroenteritis (AG) cases is detected among tourists staying at the same accommodation, outbreak management plans must be activated in a timely manner to prevent large outbreaks. Syndromic surveillance data collected between 1 January 2010 and 31 December 2013 by five seagoing cruise ships were analysed to identify attack rate thresholds for early outbreak detection. The overall incidence rate of AG was 2.81 cases per 10,000 traveller-days (95% confidence interval (CI): 0.00-17.60), while the attack rate was 19.37 cases per 10,000 travellers (95% CI: 0.00-127.69). The probability of an outbreak occurring was 11% if 4 per 1,000 passengers reported symptoms within the first 2 days of the voyage, and this increased to 23 % if 5 per 1,000 passengers reported such within the first 3 days. The risk ratio (RR) for outbreak occurrence was 2.35, 5.66 and 8.63 for 1, 2 and 3 days' delay of symptoms reporting respectively, suggesting a dose-response relationship. Shipping companies' policies and health authorities' efforts may consider these thresholds for initiating outbreak response measures based on the number of cases according to day of cruise. Efforts should focus on ensuring travellers report symptoms immediately and comply with isolation measures.

Keywords: cruise; gastroenteritis; health; maritime; norovirus; ship; threshold; travel.

• Diarrhea / epidemiology*
• Diarrhea / etiology
• Disease Notification
• Disease Outbreaks / prevention & control*
• Early Diagnosis
• Gastroenteritis / diagnosis
• Gastroenteritis / epidemiology*
• Middle Aged
• Sentinel Surveillance*
• Ships* / statistics & numerical data
• Travel* / statistics & numerical data

CDC Reveals Outbreak on Cruise Ship From ‘Unknown’ Illness

Friends Read Free

The U.S. Centers for Disease Control and Prevention (CDC) reported that more than two dozen people on board a cruise ship fell ill due to a gastrointestinal outbreak.

The predominant symptom was diarrhea, the agency reported. Other details were not provided about what may have caused it.

The CDC has previously noted that norovirus can spread quickly on cruise lines, and multiple norovirus outbreaks on cruise ships have been reported over the years to the agency.

Silversea Cruises, which is described as a luxury line, quarantined the impacted passengers and one crew member, according to the CDC. It also “increased cleaning and disinfection procedures,” the agency said.

It also “made announcements to notify onboard passengers and crew of the outbreak, encourage case reporting, and encourage good hand hygiene,” the CDC said. The CDC is now “remotely monitoring the situation, including reviewing the ship’s outbreak response and sanitation procedures.”

“To maintain an environment that supports the highest levels of health and safety onboard our ships, we implement rigorous cleaning procedures, many of which far exceed public health guidelines,” the spokesperson added. No other details were provided by the firm.

The Silversea incident marks the fourth such outbreak in 2024, according to CDC data.

In a normal year, according to the CDC, norovirus causes between 19 million and 21 million cases of vomiting and diarrhea, 109,000 hospitalizations, and 900 deaths across the United States. The virus also is associated with about 495,000 emergency department visits, mostly in younger children, the CDC says.

If there is a new strain of the virus, the CDC says, there can be upward of 50 percent more norovirus illnesses in a given year.

The CDC’s webpage for norovirus says the virus is very contagious and generally causes vomiting and diarrhea. “Anyone can get infected and sick with norovirus. Norovirus is sometimes called the ’stomach flu‘ or ’stomach bug,’” the agency says. “However, norovirus illness is not related to the flu.”

“These outbreaks often get media attention, which is why some people call norovirus the ‘cruise ship virus,’” the CDC says. “However, norovirus outbreaks on cruise ships account for only a small percentage ... of all reported norovirus outbreaks. Norovirus can be especially challenging to control on cruise ships because of the close living quarters, shared dining areas, and rapid turnover of passengers.”

“Currently, norovirus outbreak activity in the United States is within the range we would expect for this time of year and is within the range reported during the same time periods in previous years,” a spokesperson for CDC told NBC’s “Today” show on Thursday.

Justice Alito Questions Whether Prosecuting Presidents Would Undermine the Government

CDC Issues Health Alert on ‘Adverse Effects’ From Counterfeit Drug

Outspoken Billionaire Says He’s Considering Voting for Trump

Trump Says He Will ‘Make a Play’ to Win New York in 2024 While He’s on Trial

Acute Gastroenteritis on Cruise Ships — United States, 2008–2014

Weekly / January 15, 2016 / 65(1);1–5

Amy L. Freeland, PhD 1 ; George H. Vaughan Jr, MPH 1 ; Shailendra N. Banerjee, PhD 2 ( View author affiliations )

What is already known on this topic?

From 1990 to 2004, the reported rates of diarrheal disease (three or more loose stools or a greater than normal amount in a 24-hour period) on cruise ships decreased 2.4%, from 29.2 cases per 100,000 travel days to 28.5 cases. In 2001, the Vessel Sanitation Program and the cruise industry expanded the diarrheal illness case definition to include acute gastroenteritis (diarrhea, or vomiting that is associated with loose stools, bloody stools, abdominal cramps, headache, muscle aches, or fever). The most common causative agent has been norovirus.

What is added by this report?

From 2008 to 2014, the rate of acute gastroenteritis on cruise ships decreased among passengers from 27.2 cases per 100,000 travel days in 2008 to 22.3 in 2014, while the rate among crew members was essentially unchanged. The rate among both passengers and crew members was higher in 2012 compared with the preceding and following years, likely because of the emergence of a new norovirus strain. Among 73,599,005 passengers on cruise ships during 2008–2014, a total of 129,678 (0.18%) cases of acute gastroenteritis were reported during outbreak and nonoutbreak voyages; among 28,281,361 crew members, 43,132 (0.15%) cases were reported. Only a small proportion of those cases were part of a norovirus outbreak.

What are the implications for public health practice?

Cases of acute gastroenteritis illness on cruise ships are relatively infrequent. Norovirus, the most common causative agent of outbreaks, accounted for 14,911 cases among passengers and crew members during 2008–2014, 0.01% of the estimated number of norovirus cases in the United States during the study period. To further reduce acute gastroenteritis on cruise ships, travelers should practice good hand hygiene, especially after using the toilet and before touching the face or eating; persons experiencing diarrhea or vomiting should promptly report their illness for proper assessment, treatment, and monitoring.

From 1990 to 2004, the reported rates of diarrheal disease (three or more loose stools or a greater than normal frequency in a 24-hour period) on cruise ships decreased 2.4%, from 29.2 cases per 100,000 travel days to 28.5 cases ( 1 , 2 ). Increased rates of acute gastroenteritis illness (diarrhea or vomiting that is associated with loose stools, bloody stools, abdominal cramps, headache, muscle aches, or fever) occurred in years that novel strains of norovirus, the most common etiologic agent in cruise ship outbreaks, emerged ( 3 ). To determine recent rates of acute gastroenteritis on cruise ships, CDC analyzed combined data for the period 2008–2014 that were submitted by cruise ships sailing in U.S. jurisdiction (defined as passenger vessels carrying ≥13 passengers and within 15 days of arriving in the United States) ( 4 ). CDC also reviewed laboratory data to ascertain the causes of acute gastroenteritis outbreaks and examined trends over time. During the study period, the rates of acute gastroenteritis per 100,000 travel days decreased among passengers from 27.2 cases in 2008 to 22.3 in 2014. Rates for crew members remained essentially unchanged (21.3 cases in 2008 and 21.6 in 2014). However, the rate of acute gastroenteritis was significantly higher in 2012 than in 2011 or 2013 for both passengers and crew members, likely related to the emergence of a novel strain of norovirus, GII.4 Sydney ( 5 ). During 2008–2014, a total of 133 cruise ship acute gastroenteritis outbreaks were reported, 95 (71%) of which had specimens available for testing. Among these, 92 (97%) were caused by norovirus, and among 80 norovirus specimens for which a genotype was identified, 59 (73.8%) were GII.4 strains. Cruise ship travelers experiencing diarrhea or vomiting should report to the ship medical center promptly so that symptoms can be assessed, proper treatment provided, and control measures implemented.

According to U.S. Foreign Quarantine regulations, passenger vessels, including cruise ships, are required to report the number of persons meeting the diarrheal disease case definition to U.S. authorities at CDC’s Vessel Sanitation Program (VSP) 24–36 hours before arriving in the United States from a foreign port, even if there are zero cases ( 6 ). Additional reports are required if VSP’s alert threshold is reached (≥2% cumulative attack rate* among either passenger or crew populations) or an outbreak occurs (≥3% cumulative attack rate among either passenger or crew populations); outbreaks of diarrheal disease are posted on VSP’s website ( http://www.cdc.gov/nceh/vsp ). In 2001, VSP and the cruise industry expanded the diarrheal illness case definition to include acute gastroenteritis to more thoroughly detect and respond to illnesses that cause diarrhea and vomiting ( 4 ).

Data for 2008–2014 were analyzed per ship and voyage, using the most recently submitted report. Only voyages of 3–21 days in duration were included in the analysis, because cruise-associated illnesses associated with voyages of <3 days are more likely to manifest after disembarkation and, among voyages longer than 21 days (such as world cruises), report data often are incomplete. Voyages were included if they carried ≥100 passengers, because small vessels can meet VSP’s outbreak threshold with a single case; however, 99% of vessels submitting reports carried >100 passengers. Rates of acute gastroenteritis illness for both passenger and crew populations were calculated as the number of persons ill per 100,000 travel days and assessed for seasonality. Frequency of outbreaks per 1,000 voyages and the number of outbreaks per 10 million travel days also were calculated. The trend for each of these rates during 2008–2014 was assessed by fitting a linear regression line, and the trend for the actual number of outbreaks during this period was evaluated by Cochran-Armitage trend test. The rates per 100,000 travel days for 2011 and 2012, and for 2012 and 2013 were compared separately using a z-test. Similarly, the numbers of outbreaks per 1,000 voyages and per 10 million travel days for the same pairs of years were compared using a t-test and z-test, respectively.

During 2008–2014, a total of 32,084 voyages required submission of a VSP report, ranging annually from 4,404 in 2012 to 4,808 in 2014 ( Table ); among these, 29,107 (90.7%) were voyages of 3–21 days and included >100 passengers. Among a total of 73,599,005 passengers who traveled during this period, 129,678 (0.18%) cases of acute gastroenteritis were reported; and among 28,281,361 crew members, † 43,132 (0.15%) cases were reported.

The rate of acute gastroenteritis per 100,000 travel days among passengers ranged from 20.9 in 2013 to 27.2 in 2008, and among crew members, from 19.3 in 2013 to 21.6 in 2014. The rate of illness demonstrated a decreasing but not statistically significant trend for either passengers (p = 0.16) or crew members (p = 0.96). However, the rates for passengers and crew members were significantly higher in 2012 than in 2011 (passengers: p<0.01; crew members: p = 0.02) and 2013 (passengers: p<0.01; crew members: p<0.01). Monthly rates during 2008–2014 were higher during October–April ( Figure 1 ).

The number of annual acute gastroenteritis outbreaks among passengers ranged from 15 in 2011 and 2014, to 27 in 2012 (3.0–6.5 outbreaks per 1,000 voyages), and among crew members, ranged from one in 2008, 2011, 2012, and 2013 to four in 2009 and 2014 (0–0.8 outbreaks per 1,000 voyages) (Table); these differences exhibited a decreasing, although not statistically significant, linear trend (passengers: p = 0.89; crew members: p = 0.98). All but one of the crew outbreaks occurred concurrently with a passenger outbreak.

The number of outbreaks per 10 million travel days varied by year, ranging from 1.8 (2014) to 3.3 (2012) for passengers and from 0.3 (2013) to 1.5 (2009) for crew members. Although the raw number of outbreaks and rates per 10 million travel days decreased over time, the differences were not statistically significant (passengers: p = 0.52 and 0.29, respectively; crew members: p = 0.96 and 0.89, respectively). However, the rate increase among passengers in 2012 was statistically significant compared with 2011 (p = 0.04) but not compared with 2013 (p = 0.06). The rate of acute gastroenteritis outbreaks among crew members in 2012 was not statistically significantly different compared with either 2011 (p = 0.50) or 2013 (p = 0.49).

Of the 29,107 voyages, 133 (0.5%) had an outbreak. Among the 95 (71%) outbreaks for which clinical specimens were available for testing, viruses were identified as the only causative agent in 87 (92%) outbreaks, bacterial agents in three (3%), both viral and bacterial agents in four (4%), and viral and parasitic agents in one (1%) outbreak. All of the viral gastroenteritis outbreaks were caused by norovirus, including four that were caused by more than one strain. The bacterial agents implicated in the cruise ship outbreaks that affected passengers were enterotoxigenic Escherichia coli (six outbreaks), Shigella sonnei (one), and Campylobacter jejuni (one). One crew-only outbreak was caused by Clostridium perfringens . In addition, the parasite Cyclospora cayetanensis caused one outbreak ( Figure 2 ). There were 129,678 passenger acute gastroenteritis cases during the study period. Only 19,273 (14.9%) of these cases were part of an outbreak (133 outbreaks on 29,107 voyages), and 13,568 (70.4%) cases were part of an outbreak in which the causative agent was laboratory-confirmed norovirus. Similarly, there were 43,132 crew member acute gastroenteritis cases of which only 1,984 (4.6%) were part of an outbreak, and 1,343 (67.7%) were part of an outbreak caused by norovirus.

Approximately 73.5 million passengers sailed on voyages that required a VSP report during 2008–2014. During that period, 172,810 passengers and crew members met VSP’s case definition for acute gastroenteritis, accounting for 0.18% of passengers and 0.15% of crew members (outbreak and nonoutbreak illnesses combined). Among cruise ship outbreaks with clinical specimens tested, 92% were caused by norovirus, with enterotoxigenic E. coli the second most common etiologic agent. Noroviruses are highly transmissible, can spread easily, especially in environments where persons live in close quarters such as long-term care facilities or dormitories, and can remain infectious on environmental surfaces for long periods of time ( 7 , 8 ). Good hand hygiene is vital to preventing outbreaks of acute gastroenteritis, including on cruise ships. This is best accomplished by washing hands with soap and water because it allows for the mechanical removal of the virus from the hands ( 7 , 9 ). Alcohol-based hand sanitizer use alone has shown limited efficacy, but can be used in conjunction with handwashing with soap and water ( 7 ).

The enterotoxigenic E. coli outbreaks all occurred outside the United States on ships sailing back to the United States after visiting Central or South America. Overall, 14,911 passenger and crew acute gastroenteritis cases were associated with norovirus outbreaks during 2008–2014; these accounted for only 0.01% of the estimated 140 million norovirus cases in the United States during that period ( 3 ). Monthly rates of acute gastroenteritis on cruise ships were higher during October–April for all years of the study period, with the highest rates of illness occurring during 2012, when a novel strain of norovirus was identified (GII.4 Sydney) ( 5 ). The overall seasonality and higher levels of illness in 2012 were similar to non-cruise ship U.S. acute gastroenteritis outbreak data, which showed higher rates of illness during November–April each year, and more norovirus illnesses during years when a novel strain of the virus was identified ( 3 ).

Rates of acute gastroenteritis and the number of acute gastroenteritis outbreaks were consistently lower among crew members than passengers, likely for multiple reasons. First, there are strict reporting and isolation requirements for crew members who experience acute gastroenteritis ( 4 ). Crew members who do not report symptoms of diarrhea or vomiting face discipline, which can include employment termination, because the risk they pose either through food handling or passenger interactions can lead to the spread of acute gastroenteritis. Additionally, because good hand hygiene is known to limit the spread of norovirus ( 9 ), hand washing stations are required at the entrances to all crew eating areas, and crew members are monitored in their use. Hand washing stations also are required to be located in food handling areas such that “no employee must walk more than 8 meters (26 feet) to reach a station” ( 10 ). As an additional food safety measure, crew members are not allowed bare hand contact with ready to eat foods ( 4 ). Finally, cruise lines have worked diligently to remove reporting barriers for passengers and crew members and encourage immediate reporting of any diarrhea or vomiting for medical assessment, treatment, and monitoring.

The findings in this report are subject to at least four limitations. First, voyages that did not include a foreign port or did not exceed VSP’s alert or outbreak thresholds were not required to have a VSP report submitted, so the results might not reflect all voyages that occurred in U.S. waters. Second, VSP reports are only required when sailing from a foreign port to a U.S. port or when the cumulative incidence of acute gastroenteritis in either passenger or crew populations exceeds VSP’s alert or outbreak thresholds; ships sailing between U.S. ports with a cumulative incidence lower than VSP’s thresholds are not required to submit a report. Therefore, these data might not reflect the final case count at the end of the voyage. Third, case counts reported by ships and included in this study include only those persons who had symptoms while on the cruise ship and reported their symptoms to a crew member. The number of persons who experienced symptoms of acute gastroenteritis but did not report them is not known; thus, total case counts are likely underreported. Finally, in 2011, VSP included the phrase “or what is above normal for the individual” to the definition of diarrhea to align with federal regulation and the World Health Organization definition of diarrhea. This addition might have affected the number of persons who met the case definition because the definition now requires an assessment of “normal” rather than simply noting a frequency of ≥3 episodes in 24 hours.

The number and severity of cruise ship outbreaks of acute gastroenteritis varied during the study period, but were lower than rates reported during 2001–2004 ( 2 ). Collaborative efforts with the cruise industry have allowed VSP to provide more rapid support to cruise lines and ships experiencing higher than expected levels of acute gastroenteritis. Fewer and less severe outbreaks are likely the result of earlier detection of acute gastroenteritis, along with cruise industry efforts to identify and control outbreaks by developing and implementing required Outbreak Prevention and Response Plans ( 4 ), using processes and chemical disinfectants known to be effective against a norovirus surrogate and proactively seeking strategies to limit acute gastroenteritis spread, using the most currently available evidence.

Acknowledgments

Jaret Ames, Charles Otto, Aimee Treffiletti, Robert Quattlebaum, Larise Jackson, Stephanie Lawrence, Yolanda Allen, Vessel Sanitation Program, Division of Emergency and Environmental Health Services, National Center for Environmental Health, CDC; Jan Vinje, Nicole Gregoricus, Leslie Barclay, Sarah Shirley, National Calicivirus Laboratory, National Center for Immunization and Respiratory Diseases, CDC; Cheryl Bopp, Michele Parsons, Deborah Talkington, Enteric Diseases Laboratory Branch, Division of Foodborne, Waterborne, and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, CDC; Barbara Herwaldt, Parasitic Diseases Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, CDC; participating cruise lines.

Corresponding author: Amy L. Freeland, [email protected] , 770-488-7140.

1 Vessel Sanitation Program, Division of Emergency and Environmental Health Services, National Center for Environmental Health, CDC; 2 Division of Emergency and Environmental Health Services, National Center for Environmental Health, CDC.

• Cramer EH, Gu DX, Durbin RE; Vessel Sanitation Pogram Environmental Health Inspection Team. Diarrheal disease on cruise ships, 1990–2000: the impact of environmental health programs. Am J Prev Med 2003;24:227–33. CrossRef external icon PubMed external icon
• Cramer EH, Blanton CJ, Blanton LH, Vaughan GH Jr, Bopp CA, Forney DL; Vessel Sanitation Program Environmental Health Inspection Team. Epidemiology of gastroenteritis on cruise ships, 2001–2004. Am J Prev Med 2006;30:252–7. CrossRef external icon PubMed external icon
• Hall AJ, Lopman BA, Payne DC, et al. Norovirus disease in the United States. Emerg Infect Dis 2013;19:1198–205. CrossRef external icon PubMed external icon
• Vessel Sanitation Program. 2011 operations manual. Atlanta, GA: US Department of Health and Human Services, CDC, Vessel Sanitation Program; 2011. http://www.cdc.gov/nceh/vsp/operationsmanual/opsmanual2011.pdf pdf icon .
• Leshem E, Wikswo M, Barclay L, et al. Effects and clinical significance of GII.4 Sydney norovirus, United States, 2012–2013. Emerg Infect Dis 2013;19:1231–8. CrossRef external icon PubMed external icon
• Foreign quarantine. 42 C.F.R. Part 71. Washington DC: US Government Publishing Office; 2010. https://www.gpo.gov/fdsys/granule/CFR-2010-title42-vol1/CFR-2010-title42-vol1-part71/content-detail.html external icon .
• Hall A, Vinje J, Lopman B, et al. Updated norovirus outbreak management and disease prevention guidelines. MMWR Recomm Rep 2011;60(No. RR-03). PubMed external icon
• Zheng DP, Widdowson MA, Glass RI, Vinjé J. Molecular epidemiology of genogroup II-genotype 4 noroviruses in the United States between 1994 and 2006. J Clin Microbiol 2010;48:168–77. CrossRef external icon PubMed external icon
• Wikswo ME, Cortes J, Hall AJ, et al. Disease transmission and passenger behaviors during a high morbidity norovirus outbreak on a cruise ship, January 2009. Clin Infect Dis 2011;52:1116–22. CrossRef external icon PubMed external icon
• Vessel Sanitation Program. 2011 construction guidelines. Atlanta, GA: US Department of Health and Human Services, CDC, Vessel Sanitation Program; 2011. http://www.cdc.gov/nceh/vsp/constructionguidelines/constructionguidelines2011.pdf. pdf icon

* Cumulative attack rate refers to the attack rate for an entire voyage.

† Represents the sum of crew members for each voyage reported to VSP.

TABLE . Acute gastroenteritis illness among passengers and crew members on cruise ships — United States, 2008–2014

*A novel strain of norovirus (GII.4 Sydney) emerged in 2012. † Statistically significant increases: 2012 compared with 2011 and 2013.

FIGURE 1 . Monthly rates of acute gastroenteritis cases on cruise ships, by patient type — Vessel Sanitation Program, United States, 2008–2014*

* Data combined for the period 2008–2014, and incidence calculated by month.

FIGURE 2 . Number of acute gastroenteritis outbreaks* on cruise ships, by year and causative agent type — Vessel Sanitation Program, United States, 2008–2014

* Five acute gastroenteritis outbreaks on cruise ships had more than one causative agent.

Suggested citation for this article: Freeland AL, Vaughan GH Jr, Banerjee SN. Acute Gastroenteritis on Cruise Ships — United States, 2008–2014. MMWR Morb Mortal Wkly Rep 2016;65:1–5. DOI: http://dx.doi.org/10.15585/mmwr.mm6501a1 external icon .

MMWR and Morbidity and Mortality Weekly Report are service marks of the U.S. Department of Health and Human Services. Use of trade names and commercial sources is for identification only and does not imply endorsement by the U.S. Department of Health and Human Services. References to non-CDC sites on the Internet are provided as a service to MMWR readers and do not constitute or imply endorsement of these organizations or their programs by CDC or the U.S. Department of Health and Human Services. CDC is not responsible for the content of pages found at these sites. URL addresses listed in MMWR were current as of the date of publication.

All HTML versions of MMWR articles are generated from final proofs through an automated process. This conversion might result in character translation or format errors in the HTML version. Users are referred to the electronic PDF version ( https://www.cdc.gov/mmwr ) and/or the original MMWR paper copy for printable versions of official text, figures, and tables.

Exit Notification / Disclaimer Policy

• The Centers for Disease Control and Prevention (CDC) cannot attest to the accuracy of a non-federal website.
• Linking to a non-federal website does not constitute an endorsement by CDC or any of its employees of the sponsors or the information and products presented on the website.
• You will be subject to the destination website's privacy policy when you follow the link.
• CDC is not responsible for Section 508 compliance (accessibility) on other federal or private website.