Chapter 6Conveyance & Transportation Issues

Douglas D. Slaten, Kiren Mitruka

INTRODUCTION

The cruise ship market is the fastest-growing sector of the travel industry. In 2008, the North American cruise industry, which makes up most of the global cruise market, comprised 161 ships carrying more than 13 million passengers to destinations worldwide. Nearly 9 million cruise passengers left from US ports. Florida is the center of US cruise ship travel, accounting for more than half of all US departures. The Caribbean is the top destination, followed by the Mediterranean, Europe, and Alaska. The average length of a cruise is 7 days, although voyages range from a few hours (“voyages to nowhere”) to several months for around-the-world cruises. A typical cruise ship carries approximately 2,000 passengers and 800 crew members; however, cruise ship capacities continue to increase and can exceed 5,000 passengers and 2,000 crew. The median age of a cruise ship passenger is 46 years; seniors (≥55 years) represent approximately one-third of passengers. To a certain extent, different cruise lines target different population groups, and longer cruises often attract older passengers.

While most passengers are from the United States or Canada, cruise ships bring together large numbers of people from a variety of communities and backgrounds. Communicable diseases can be introduced onboard by embarking travelers, or acquired during visits to seaports with varying risks of exposure to infectious diseases. The crowded, semi-enclosed environment of the cruise ship facilitates transmission of communicable disease, either person to person or from contaminated food, water, or environmental surfaces. The stress of travel can worsen chronic conditions in specific groups, such as pregnant women and the elderly, who may be more seriously affected by infectious illnesses. Additionally, crew members, who are often from developing countries that may lack routine vaccination programs, can be sources of infection for vaccine-preventable diseases.

HEALTH AND SAFETY REGULATIONS

In 2005, the World Health Organization revised the International Health Regulations, which provide international standards for ship and port sanitation, disease surveillance, and response to infectious diseases. The 2005 revision entered into force in June 2007. The regulations are binding on 194 countries and are intended to help the international community prevent and respond to acute public health risks worldwide (www.who.int/ihr/en).

The Coast Guard enforces safety and security regulations in US waters, and CDC ensures health and sanitation aboard ships with international itineraries arriving at US ports. Federal regulations require such ships to report all shipboard deaths, and certain illnesses suggestive of communicable diseases, 24 hours before arrival at a US seaport. One of CDC’s 20 quarantine stations with jurisdiction over the seaport of arrival responds to these reports, providing recommendations to prevent the spread of illness (www.cdc.gov/quarantine/index.html). Since 1975, CDC’s Vessel Sanitation Program (VSP) has also helped the cruise ship industry prevent and control gastrointestinal illnesses on cruise ships (www.cdc.gov/nceh/vsp).

CRUISE SHIP MEDICAL CAPABILITIES

Medical facilities on cruise ships can vary widely, depending on a number of ship and traveler characteristics. Generally, shipboard medical clinics are comparable to ambulatory care centers. Although no official agency regulates medical practice aboard cruise ships, consensus-based guidelines have been published, which cruise lines are encouraged to adopt. The Cruise Lines International Association (CLIA) represents 25 major cruise lines, accounting for more than 97% of the North American cruise market (www.cruising.org). CLIA’s Medical Facilities Working Group developed industrywide guidelines and recommends cruise ship medical facilities have the capability to:

• Provide emergency medical care for passengers and crew
• Stabilize patients and initiate reasonable diagnostic and therapeutic intervention
• Facilitate the evacuation of seriously ill or injured patients

In 2010, the American College of Emergency Physicians, Section of Cruise Ship and Maritime Medicine, published revised Health Care Guidelines for Cruise Ship Medical Facilities (www.acep.org/practres.aspx?LinkIdentifier=id&id=29980&fid=2184&Mo=No). These guidelines include recommendations for a ship medical center, staffed by physicians and registered nurses on call 24 hours per day. Although the needs of individual ships vary, these guidelines describe desired physician and nurse competencies (including physician board certification in emergency medicine, family practice, or internal medicine), as well as training in drills and preferred shipboard medications and supplies, laboratory and x-ray capabilities, and health equipment.

CRUISE SHIP ILLNESSES AND INJURY

Cruise ship medical clinics deal with a wide variety of illnesses and injuries. Most health-related events are treated or managed onboard. However, medical evacuation and shoreside consultation, particularly for dental problems, are not infrequent. The proportion of reported urgent or emergency conditions is 3%–11%.

Published reviews of cruise ship medical logs have shown that most passenger dispensary visits on cruise ships were due to medical conditions (69%–88%). Respiratory (19%–29%) and gastrointestinal (9%) illnesses were the most frequently reported diagnoses. Injuries accounted for 12%–18% of medical visits.

The most frequently documented cruise ship outbreaks involve respiratory infections (influenza and legionellosis), gastrointestinal infections (norovirus), and vaccine-preventable diseases other than influenza, such as rubella and varicella (chickenpox).

SPECIFIC HEALTH RISKS

Gastrointestinal Illness

VSP conducts twice-annual, unannounced inspections of ships with international itineraries that call on US seaports. In recent years, outbreaks of gastroenteritis (defined as ≥3% of passengers or crew symptomatic) on cruise ships have increased, despite good cruise ship environmental health standards. Most cruise ship gastrointestinal outbreaks are now due to norovirus, which is also the main cause of acute viral gastroenteritis in the United States. Characteristics of norovirus that facilitate outbreaks are low infective dose, easy person-to-person transmissibility, and ability to survive routine cleaning procedures.

Other organisms associated with foodborne and waterborne outbreaks on cruise ships are Salmonella, enterotoxigenic Escherichia coli, Shigella, Vibrio, Staphylococcus aureus, Clostridium perfringens, Cyclospora, hepatitis E virus, and Trichinella.

Respiratory Illness

Influenza

Since travelers originate from both the Northern and Southern Hemispheres, where the influenza seasons start in October or November and April or May, respectively, shipboard outbreaks of influenza A and B can occur year-round. Outbreaks usually result from the importation of influenza by embarking passengers and crew; infection subsequently spreads person to person.

During the 2009 influenza A (H1N1) pandemic, cruise line medical personnel made case-by-case decisions regarding the boarding of passengers with influenzalike illness. In 2003, the industry instituted similar screening protocols during the outbreak of severe acute respiratory syndrome (SARS) in Asia. Crew members can sustain influenza transmission over successive cruises. Onboard control measures travelers can expect include isolation of ill people, infection control, and antiviral treatment of ill people and contacts.

Legionellosis (Legionnaires’ Disease)

Legionnaires’ disease is a severe pneumonia caused by inhalation or aspiration of warm, aerosolized water containing Legionella. Symptom onset is typically 2–10 days after exposure. There is no person-to-person transmission.

Risk factors for Legionnaires’ disease include older age (≥65 years) and underlying medical conditions. Contaminated ships’ whirlpool spas and potable water supply systems are the most commonly implicated sources of shipboard Legionella outbreaks, although improvements in ship design and standardization of spa and water supply disinfection have reduced the risk of Legionella growth and colonization. Most cruise ships can perform Legionella urine antigen testing. CDC should be informed of any travel-associated Legionnaires’ disease cases by e-mailing travellegionella@cdc.gov.

Vaccine-Preventable Diseases

Although a ship’s passenger population is newly introduced at the beginning of each voyage, crew members remain onboard for extended periods. And, although most cruise ship passengers are from countries with routine vaccination programs (mainly the United States and Canada), crew members tend to originate from developing countries, some with low immunization rates. In past cruise ship investigations involving vaccine-preventable diseases, approximately 11% of crew members were found to be acutely infected with or susceptible to rubella, and 13% of crew, mostly from tropical countries, were susceptible to or acutely infected with varicella.

Crew members should have documented proof of immunity to vaccine-preventable diseases. Passengers should be current on routine vaccinations before travel. Women of childbearing age should be immune to rubella before cruise ship travel.

Vectorborne Diseases

Cruise ship port visits may include countries where vectorborne diseases, such as malaria, dengue, and yellow fever, are endemic. Yellow fever vaccination certificates may be required by some countries for entry. Although cruise lines may schedule arrival and departure times to avoid peak mosquito biting periods, personal protection is still necessary. Preventive measures include the following:

• Remaining in well-screened or air-conditioned areas
• Wearing clothes that cover ankles, legs, and arms
• Using an effective insect repellent (see Chapter 2, Protection against Mosquitoes, Ticks, and Other Insects and Arthropods)
• Antimalarial chemoprophylaxis based on a destination- and activity-specific risk assessment

Other Health Concerns

Stresses of cruise ship travel include varying temperature and weather conditions, as well as unaccustomed changes in diet and physical activity. Foreign travel increases the likelihood of risk-taking behaviors such as alcohol misuse, drug use, and unsafe sex. Deaths on cruise ships are most often due to cardiovascular events. In spite of modern stabilizer systems, seasickness is a common complaint (see Chapter 2, Motion Sickness). Injuries and dental emergencies are frequent occurrences.

PREVENTIVE MEASURES FOR CRUISE SHIP TRAVELERS

Cruise ship travelers often have complex itineraries due to multiple short port visits and potential exposures. Although most of these port visits do not include overnight stays off the cruise ship, many exotic trips have options for travelers to venture off the ship for one or more nights. Cruise ship travelers may be uncertain about which prevention medications, immunizations, and behaviors are appropriate for them and their itineraries. Box 6-01 summarizes recommendations for cruise travelers, and clinicians advising cruise travelers, in pre-travel preparation and healthy behaviors during travel.

After Travel

Travelers who become ill after returning home should inform their health care providers of where they have traveled. Clinicians should report suspected communicable diseases in recently returned cruise ship travelers to public health authorities. Gastrointestinal illnesses related to cruise ship travel should be directed to the CDC VSP: 800-CDC-INFO (800-232-4636) or CDCINFO@cdc.gov. Other suspected communicable illnesses should be reported to the CDC quarantine station with jurisdiction over the cruise ship’s port of arrival (http://www.cdc.gov/quarantine/QuarantineStationContactListFull.html).

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