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Cruise Ship Travel - Health Risks and Precautions

Cherinet Seid, MD LMCC CCFP
Clinical Fellow, University of Ottawa

Introduction

Cruise ship travel is a significantly growing mode of travel; 11.7 million people took cruise vacation world wide in 2006 - representing about 7% of all forms of travel1. Cruise ships are bringing passengers and crew members with diversity of culture, medical conditions and immunization statuses from all around the world. This in addition to close proximity of passengers and crew members creates a favourable environment for transmission of infectious diseases.
Non infectious problems include injuries, motion sickness, and exacerbation of pre existing medical conditions. Both infectious and non infectious hazards will be discussed further.

Cruise ship travel – Health risks

The average duration of cruise ship travel is 7 days ranging from several hours to months depending on purpose of travel1. People older than 65 comprise one –third of cruise ship travellers and one half of cruise ship infirmary visits. Along with pre existing chronic illnesses this population is at increased risk from complications of both infectious and non infectious problems. Overall 1 in 250 cruise ship passengers experience an illness while on board that requires medical attention4. Although many cruise ship travels today have basic medical services they do not have immediate back up services such as surgery, blood transfusion and detailed laboratory and radiological investigations. Medical evacuation is dependent up on the ships position at sea, the sailing itinerary and next port of call5.

*A retrospective descriptive study in a calendar year on 4 ships of a major cruise ship line with cruises originating in US. 7147 new patient visits occurred in a population of 196,171 passengers and 1,537,298 passenger days. 51% of the infirmary visitors were older than 64 years, while only 39% of overall passengers were older than that age.
#Majority of medical conditions (29.1%) was respiratory tract infections.

Currently cruise ship travel carries the most concern for out breaks compared to other modes of travel. Most of these out breaks (16/18) are by food harvested and transported from one country to another7. Hotels and ports along the way also play major role as additional sources of infection.

Table 1 Infectious disease risks in cruise ship travel4, 5, 8

Diseases	Organisms	Risks
Respiratory infections	Influenza A & B Legionella Pneumococcal	Close proximity Water sources (Shower etc) Co morbidities
Food and water borne	Norovirus , others	Close proximity Ports, hotels
Skin infections	Bacterial	Cuts, abrasions, insect bites
Mosquito borne	Malaria, Dengue ,Yellow fever	Ports, berthing out side in endemic areas but rare
STIs	All types	Casual relationships, Alcohol & drugs

Respiratory tract infections - are frequent among cruise-ship travellers. Risk of influenza is high due to large number of people travelling together, close proximity and non – seasonal circulation in certain parts of the world1.
Legionnaires’ disease is a potentially fatal form of pneumonia. Outbreaks of the disease have occurred on cruise vessels due to poor cleaning and maintenance practices of spas, fountains, and showers4.More than 50 incidents of legionellosis, involving over 200 cases, have been associated with ships during the past three decades1. In one study, 42% (38/90) water samples were contaminated by legionella spp, mainly from showers and washbasins9.
Gastrointestinal infections- most of the gastrointestinal disease outbreaks associated with cruise ships has been linked to food or water consumed on board ship. Norovirus is the most common pathogen implicated in outbreaks. It is highly contagious, transmitted through improper hygiene, person to person, via contaminated food and water, through contact with contaminated surfaces and even through particles in the air. Symptoms include vomiting, diarrhoea, abdominal cramps and low grade fever. It is usually self limited and rehydration is the main stay of treatment. Patient can remain contagious 72 hours after symptoms have disappeared4. In 2006 there were at least 32 outbreaks of norovirus like virus infection involving more than 4,000 passengers on multiple ships and cruise lines10. Other causes of gastroenteritis include Salmonella, enterotoxigenic E.coli, shigella spp, vibrio spp, staphylococcus aureus, clostridium perfringes, cyclopsora spp, and trichinella spiralis8.

Table 2 Non infectious health risks in cruise ship travel4, 5,6,11

Conditions	Risks
Injuries	Elderly, Frail, Disability, influence of alcohol, instability of ships, sea currents
Exacerbation of pre existing conditions*	Elderly, diet change & wt gain, alcohol consumption, physical inactivity, climatic variations, stress from new environment
Motion sickness	Sea travel
Sun burn	Excessive UV light exposure
Dental problems	Elderly, failure of restorations

* Cardiovascular events are the most common causes of mortality on cruise ships.

Precautions

Vaccinations – Influenza can lead to pneumonia, hospitalization and death depending on personal risk factors. Vaccination should be provided regardless of season. Ships medical unit should stock Tamiflu for treatment and in case of an out break4. Pneumococcal vaccine is recommended for elderly and others with chronic heart or lung diseases. Vaccination against hepatitis A is recommended for those cruising outside Europe and North America. Typhoid and polio boosters are suggested depending on itinerary and likely hood of taking risks when ashore.
Passengers going on cruise tour up the Amazon River need yellow fever vaccination. Yellow fever vaccination is an immigration requirement for some countries and unvaccinated passengers may not be allowed ashore. Other routine vaccinations should be received according to current guidelines. Most cruise ships have anti rabies vaccine if animal bite happens ashore, but this is rare. Hepatitis B vaccination is recommended for passengers at risk5.

Other preparations – Passengers with pre existing medical conditions should carry adequate supply of their medications. They also need summary of their medical conditions, list of their medications and recent EKG & x-ray results from their physician to the cruise ship medical team. Passengers with medical conditions and physical impairments should check with the cruise ship line about suitability of the cruise ship for them. Special cruises are now available for travellers who have certain medical conditions including those on dialysis8.
Passengers should be aware of risks and symptoms of legionellosis. Flushing through showers in hotels or institutions with hot water when they have not been used recently may help reduce risk.
Frequent hand washing & other personal hygiene precautions help reduce the spread of norovirus & other gastrointestinal infections. Passengers at risk can get medications for treatment of motion sickness. Most large modern ships have been engineered to reduce motion sickness. Injury prevention is vital especially for those at risk, and excess alcohol consumption should be avoided4,5.
Avoiding mosquito bite is the main stay of malaria and dengue prevention. Malaria chemoprophylaxis is recommended only if itinerary includes ports in endemic countries especially when accommodation is taken out side the ship. Malarone is preferred for its shorter course5.
Chance of skin infections can be reduced by disinfecting cuts, abrasions, and insect bites. Excessive sun exposure should be avoided and sunscreen used to prevent sunburn. Over exposure to sun can also increases possibility of stroke. Drinking abundant non-alcoholic fluids prevents dehydration4.
Safer sex practice including correct and consistent condom use should be discussed.
Development of symptoms up on return should alert to travel related illnesses. Any febrile illness should be considered as malaria even if risk is low. Passengers with legionellosis also can develop symptoms only up on completion of travel, resulting in delayed detection and continuous transmission12.

Summary

Travelling has come a long way to its current “level of comfort”. People can travel on air, land and sea. Each mode of travel has its own health risks and cruise ship travel is not an exception. Both infectious and non infectious risks of cruise ship travel should be thoroughly discussed with the individual traveller. Appropriate preparation before embarking on travel and follow up on return is vital.

 

References

1. WHO. Mode of Travel Health Considerations. Available at:
http://www.who.int/ith/chapter_2a_2008.pdf. (Accessed 2008 May 8).

2. World Tourism Organization. Tourism highlights 2007. Available at:
http://www.unwto.org/facts/menu.html. (Accessed 2008 May 7).

3. Ward BJ, Plourde P. Travel and Sexually Transmitted Infections. J Trav Med 2006;
13(5): 300-317. Available at: http://www.blackwell-synergy.com

4. Shoreland, Inc. Travel Health Online. Available at: https://www.tripprep.com
(Accessed 2008 May 7).

5. Health Protection Scotland. Travax, the A to Z of Healthy Travel. Available at:
http://www.travax.nhs.uk (Accessed 2008 May 10)

6. Peake DE, Gray CL, Ludwig MR, Hill CD. Descriptive epidemiology of injury and
illness among cruise ship passengers. Ann Emerg Med 1999; 33(1): 67-72.

7. Todd EC, Greig JD, Bartleson CA, Michaels BS. Outbreaks where food workers have been
implicated in the spread of foodborne disease. J Food Prot 2007; 70(8): 1975-93. Available
at: http://lib.bioinfo.pl/pmid:17803160

8. Centre for Disease Control and Prevention. CDC Health Information for
International Travel 2008. Atlanta, US: Elsevier Mosby, 2008.

9. [My paper] Azara A, Piana A, Sotgin G, Dettori M, et al. Prevalence study of legionella spp.
Conatmination in ferries and cruise ships. BMC Public Health 2006; 6:100.
Available at: http://www.biomedcentral.com/1471-2458/6/100

10. CDC. Vessel Sanitation Program. Available at: http://www.cdc.gov/nceh/vsp
(Accessed 2008 May 14).

11. Sobotta BA, John MT, Nitschke I. Cruise Medicine: The Dental Perspective on
Health Care for Passengers during a world cruise. J Trav Med 2008; 15(1): 19-24.

12. Rowbotham TJ. Legionellosis associated with ships: 1977 to 1997. Commun Dis
Public Health 1998; 1(3): 146-51. Available at: http;//www.ncbi.nlm.nih.gov

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