Updated 02 July 2014

Air travel and cruise ship health

Air travel and cruise ship health involves protecting passengers and crew members during transportation, by minimising the risks of disease and injury.


Air travel and cruise ship health involves protecting passengers and crew members during transportation, by minimizing the risks of disease and injury. Cruise vessels and airplanes follow specific guidelines and regulations to ensure safety and to prevent widespread illness; they are isolated communities with crowded accommodations, shared sanitary facilities, and common food and water supplies. Each of these conditions may promote the spread of disease. In addition, the publicity of disease outbreaks aboard a cruise ship may have a financial impact on the ship's owner and on those people who rely on the ship for transportation.

Ships have a significant impact on public health beyond their role in ship-acquired infections. For example: Ships may carry passengers who are sick; onboard personnel and travelers may unintentionally transport or transmit infectious organisms to new hosts after reaching their destination; and vessels may carry infected rodents and insects between ports. In this capacity, ships act as a means of international disease transfer. The U.S. Centers for Disease Control and Prevention (CDC) established the Vessel Sanitation Program (VSP) in 1975 with the cruise vessel industry. VSP's goal is to assist the industry in developing and implementing complete sanitation programs to protect the health of both passengers and crew aboard cruise vessels

Potential health risks are also associated with air travel. In-flight medical events are increasingly frequent because of the growing number of people with pre-existing medical conditions who continue to travel; potentially-affected passengers include those with cardiac, pulmonary, and blood-related conditions.

Air travel also plays a key role in the spread of many pathogens. Federal air travel restrictions (known as the "Do Not Board Plan" or DNB) have been created to prevent the boarding of passengers with communicable diseases; these ill people may pose a risk to others. The DNB plan is controlled and managed by the CDC and U.S. Department of Homeland Security (DHS). Under this plan, health care providers are required to contact their local health departments if they are treating patients who have serious, communicable diseases; this information is forwarded to the CDC, who may work with DHS to place the patients' names on the official DNB list for prohibited air travel within (or leaving) the United States.

Communicable diseases may be fatal, and may also be associated with high economic costs. The treatment of some of these diseases far exceeds the costs of investigating the outbreak. If a vessel reports an onboard contagious illness, the VSP conducts a thorough investigation: CDC officials determine the magnitude of the virus, identify the agent causing the illness, isolate risk factors, and formulate control measures.

Airplanes and cruise ships may contribute to pollution through improper water and waste disposal; this pollution may have a significant effect on ecosystems. For example, water pollution and soil erosion have already caused damage to some coral reefs and marine life. In addition, airplane emissions contribute significantly to air pollution.


Air travel :

General: The primary focus of air travel and cruise ship health is to prevent the development and spread of communicable disease and to minimize passenger injuries. The U.S. Centers for Disease Control and Prevention (CDC) recommends the implementation of certain regulations and procedures on both ships and planes, to ensure a healthy and safe environment. These regulations and procedures are enforced by routine inspections.

Insect control: Aircraft that travel to other countries are at risk of spreading insect-borne diseases. Airplane personnel may use insecticide sprays to eliminate mosquitoes, cockroaches, flies, and other crawling or flying insects. Disinfecting the aircraft's interior with insecticide is a public health measure required by international health regulations to protect passengers. Research has shown that insecticide sprays have no harmful effects on travelers; some passengers have complained, however, of feeling dizzy or unwell after riding in disinfected aircrafts.

Cabin pressure: Before pressurized cabins were implemented, planes could not fly over 10,000 feet without using oxygen. Now, aircraft cabins are constantly pumped with compressed air through a process called pressurization during flight, to maintain a safe and comfortable environment. Using pressurized cabins allows aircraft to travel at higher altitudes, resulting in faster flights that use less fuel. In addition, pressurization keeps the passengers and crew from falling unconscious during flight due to the lack of oxygen (hypoxia) that occurs at high altitudes. The oxygen level found in current air cabins at cruising altitude is lower than the oxygen level found at sea level.

Most passengers are not affected by the altitude difference, but at-risk travelers with pre-existing medical conditions should notify their airlines in advance to arrange for supplemental oxygen. In addition, passengers with ear, nose, and sinus infections may experience severe middle-ear and sinus pain or injury when the air in those locations expands and contracts during ascent and descent. Cabin air is also typically very dry, so passengers should limit alcohol and caffeine to avoid dehydration.

Eustachian tubes (passageways that lead from the middle ear to the back of the throat) help to equalize middle-ear and outside-the-head air pressures when passengers open their mouths; this movement allows air to reach the middle ear. When a passenger's ear "pops" while yawning or swallowing, the Eustachian tube is adjusting the air pressure in the person's middle ear. Children are more susceptible to air pressure changes because their Eustachian tubes are narrow and are still developing. Thus, children's Eustachian tubes may not function effectively during air travel, especially if the tubes are already inflamed or clogged from a cold or ear infection.

Cabin ventilation and air filtration: Airplanes recirculate air through HEPA filters, similar to those used in hospital rooms. These filters capture 99.9% of bacteria and viruses between 0.1 and 0.3 microns (micrometers) in diameter. Older airplane models provided 100% fresh air to their cabins, but this practice resulted in high fuel consumption. In the late 1980s, aircraft began to mix 10%-50% of the recirculated air in their cabins with outside air to conserve fuel and energy. Some research indicates, however, that aircrafts' overhead ventilation systems may help to spread communicable diseases from infected passengers to healthy onboard travelers.

Pollution: Increased air traffic has led to the classification of airports and aircraft as two of the greatest sources of air pollution. According to the Center for Climate Change and Environmental Forecasting, carbon and other emissions constitute about 70% of the polluting discharges from aircraft. Aircraft greenhouse-gas emissions, such as carbon dioxide and nitrogen oxides, also contribute to ozone depletion. These high-altitude emissions may have an impact on global warming, in addition to polluting the air that humans breathe. Some preventive measures to reduce flight-based pollution are being taken by aircraft manufacturers; for example, firms are using lighter materials to build their airplanes and are powering them with more fuel-efficient jet engines. The Federal Aviation Administration is also working on ways to reduce U.S. aircraft greenhouse-gas emissions.

Cruise ship vessels :

General: The Cruise Lines International Association (CLIA) is a non-profit industry trade association. The cruise industry's highest priority is to provide passengers with a safe, healthy, and comfortable environment. Ships must meet criteria established by the Vessel Sanitation Program (VSP) in the Vessel Sanitation Program Operations Manual. Inspections are conducted by VSP Environmental Health Officers and take place only in U.S. ports. To maintain a healthy and sanitary environment for passengers and crew, the VSP inspects the following in each cruise vessel: medical facilities, housekeeping operations, portable water systems, swimming pools and spas, childcare centers, food prep areas, ventilation systems, and common areas.

Medical facilities: The cruise industry has taken a proactive role in addressing the quality of shipboard medical care. All cruise ships are required to have a private medical facility with licensed doctors, registered nurses, and a pharmacy. In the event of a serious ailment, patients are taken to the nearest medical facility on land for treatment.

Each medical facility is equipped with items such as medical waste and personal protective equipment, IV fluids and supplies, lab supplies, X-ray equipment, diagnostic equipment, beds, dressings, airway equipment, and defibrillators. The VSP inspects these facilities to make sure they provide gastrointestinal illness surveillance and keep medical logs.

Housekeeping operations: Housekeeping is important for maintaining sanitation regulations and infectious control. The Vessel Sanitation Program (VSP) has created a model format for cleaning, which outlines proper sequences and evaluates the number and location of hand-washing stations for housekeeping staff on each vessel. The VSP also requires that all objects and surfaces in cabins be cleaned and disinfected between occupancies or every seven days. This includes beds, sheets, glasses, tabletop surfaces, bathrooms, private whirlpools, and ice buckets. Since toilet rooms can be heavily contaminated with pathogenic microorganisms, they must also be disinfected within the same criteria. The CDC requires all public restrooms onboard to be hands-free to greatly reduce the spread of pathogens from passenger to passenger. The International Council of Cruise Lines (ICCL) requires cruise vessels to instruct housekeeping staff to place personal articles left on balconies by room occupants back in their rooms. This is important to prevent the spread of a possible fire on deck. It is also important that common areas on deck are regularly cleaned and sanitized to prevent rodents and insects.

Portable water systems: Many gastrointestinal illnesses are transmitted by contaminated portable water. The VSP recommends that all portable water systems are stored and protected in appropriate locations to prevent contamination. Tanks should be constructed of metal or other suitable material, and designed with easy access for cleaning, repair, draining, and maintenance. Vents prevent the entrance of contaminated objects or foreign bodies. Hazards associated with storage tanks include sediment build-up at the tank's bottom, damage to vents or pipes, contamination, and leakage. Ship operators must implement control measures for each hazard and perform routine inspections, repairs, cleaning, and maintenance of tanks to keep water supplies safe.

Swimming pools and spas: Swimming pools and spas may present a number of health risks. The most significant dangers are accidental drowning, slipping, becoming caught on ropes or fences, and exposure to infectious disease and hazardous chemicals. Fecal-oral pathogens, such as food-borne illnesses, may infect bathers in swimming pools and spas. The CDC states that water in pools and spas must be hygienically safe and limit pathogens to acceptable levels. Disinfection, pool hydraulics, water treatments, and the addition of fresh water at numerous intervals must be of safe design and meet water quality standards. Circulation and hydraulics ensure that treated water gets to all parts of the pool, and that polluted water is removed. Filtration is crucial, both because it keeps water clear so swimmers can see each other clearly and avoid accidents, and to remove protozoa that are relatively resistant to the chlorine disinfection. Spa pools present a special set of problems because they are ideal habitats for water-generated bacteria, such as Legionella. Legionella bacteria will thrive in warm water. The ideal temperature for growth is 95-115o F, and growth can occur up to 122oF. Disinfection, high rates of water exchange, and superheating water to 180oF, when not in use at all, helps control microbial production. Vessels may use either seawater or clean portable water as a source.

Childcare centers: Childcare facilities may be breeding grounds for viruses and bacteria. Many common viral and bacterial infections on vessels are communicable by touch. Toys and surfaces located in the facilities are more likely to become contaminated due to the amount of children playing with them or touching them. Childcare facilities aboard vessels are often set up to accommodate appropriate age groups, such as children age six and under. Where babies are cared for, requirements must be met to maintain a sanitary and healthy environment. Durable, non-absorbent changing tables must be present, as well as a supply of disposable diapers, gloves, sanitary wipes, disinfecting cleanser, and an airtight diaper receptacle for soiled diapers. All toys must be cleaned and disinfected to prevent transmission of infectious illnesses. Employees are trained to recognize signs of infectious childhood illnesses, such as vomiting, diarrhea, fever, rash, swollen glands, discharge from the nose or eyes, and constant crying. Any child that becomes sick, while in or before entering the childcare center, is sent to the medical facility by the staff or parents, and needs medical clearance to return.

Food preparation areas: The Vessel Sanitation Program (VSP) enforces strict regulations regarding food prep areas to prevent transmission of food borne illness. The majority of foodborne outbreaks has been caused by pathogenic bacteria, such as salmonella and E. coli. The causes of such outbreaks include inadequate temperature control, infected food handlers, cross contamination, inadequate heat treatment, contaminated raw ingredients, and the use of seawater in the galley.

Bacteria and fungi present the greatest risk for infection and disease. Both raw and cooked food may provide a lush medium and support rapid growth of these organisms. Therefore, contamination levels in raw food should be minimized, even if it is to be cooked. Contamination can be avoided by avoiding cross-contamination of uncooked meats with produce and cooked foods. The prime risk factor is contamination by food handlers with unwashed hands.

To prevent growth of and contamination by such bacteria, there are certain guidelines and layouts that must be considered in the design of each ship. The surfaces of walls and partitions must be made of bacteria-resistant materials with no toxic effects, decks and flooring should be constructed and maintained for easy cleaning, windows should be easy to clean and fitted with removable insect-proof screens, and work areas where food is handled should be in sound condition.

There must also be appropriate ventilation, lighting, water facilities, and storage to protect food from contamination. All food must be obtained from shore sources that are approved or considered satisfactory by the Occupational Safety and Health Administration (OSHA). Food should be clean, wholesome, free from spoilage and corruption, and safe for human consumption. Food and water must be properly stored in containers that are insect- and rodent-proof. Raw materials and ingredients should not be accepted by the ship if they are known to contain parasites, pesticides, or toxins.

Refrigeration: Inadequate control of food temperature is one of the most common causes of food-borne illness and food spoilage on ships. Regulation guidelines stress that all refrigerators be constructed so they can be readily cleaned, and they must be kept clean and in good repair. Sufficient shelving must be provided in all units to prevent stacking and permit ventilation. All perishable foods should be kept at 40 degrees Fahrenheit (oF). Fruits and vegetables should be stored in cool rooms. Meat and fish should be maintained at 32- 37oF; milk and milk products should be stored at 40o F. All frozen foods should be kept below 10o F.

Ventilation system: Certain pathogens may thrive in ventilation systems or heating, ventilation, and air conditioning (HVAC) systems. It is important that they are designed and constructed to be accessible for inspection, maintenance, and cleaning on cruise ship vessels. They must also be self-draining to ensure that bacteria do not grow in standing water. Vessels are required to clean the cooling coils and drip or condensate pans of air-handling systems, which are systems that condition and circulate air as part of ventilation, heating, and air conditioning. Evaporative condensers are inspected at least annually and cleaned as necessary. Proper maintenance and development of these systems help prevent the production of disease and also reduce energy consumption.

Pollution: Cruise ships generate high volumes of pollution each day. They can generate up to 25,000 gallons of sewage from toilets and 143,000 gallons of sewage from sinks, galleys and showers each day. Lax state and federal laws allow ships to dump treated and untreated sewage from toilets, sinks, and showers once the ship is at least three miles from shore. Cruise ships are required to have onboard waste treatment systems, referred to as marine sanitation devices (MSDs), but ships are not required to report MSD discharges to the government or public.

Ships produce many types of wastewater. The two most common are black and gray water. Black water is sewage from toilets and medical facilities that contains pathogens and bacteria. Black water can kill aquatic life. Gray water, the largest source of liquid waste generated by cruise ships, is wastewater from the sinks, showers, laundry, and galleys. It may contain detergents, oils, metals, and food waste. The Clean Cruise Ship Act of 2008 prohibits cruise vessels in U.S. ports from discharging sewage, gray water, or bilge water into U.S. waters; exceptions are included. Cruise ships also have diesel engines that discharge air pollution, which is extremely hazardous to sea life and persons with asthma and respiratory illnesses. Diesel exhaust is a mixture of particles and gases. It contains more than several hundred different organic and inorganic components, including many chemicals that have been designated as toxic air pollutants. Because mutagens and carcinogens are present in both the gaseous and particulate components, lung cancer has been the focus of attention as a health risk in animal and human research. Exposure to diesel fumes can also affect the central nervous system, inducing a stress response.


The partnership of the U.S Centers for Disease Control and Prevention (CDC) and the cruise industry has expanded health and safety training and education, as well as inspection programs. One study that evaluated 15 years of ship sanitation inspection data from the National Center of Environmental Health and reviewed performance in specific sanitation categories from 1996 to 2005, found improvements in cruise ship sanitation inspections. Inspections with violations decreased in several categories, including washing facilities, contact surfaces, facility maintenance, food handling, and communicable disease practices. Inspection violations increased for swimming pools and water system protection. The overall good performance in sanitation categories is likely due to on-site training during inspections and improvements regarding vessel construction.

Noroviruses continue to be the most prominent viruses on cruise vessels. The Vessel Sanitation Program's (VSP) main goal is to prevent and control outbreaks of noroviral infection. In 2006, several cruise-related viral gastroenteritis outbreaks were reported in Europe. A study of 137 people onboard one ship involved collecting stool, food, water, and surface samples. Researches found that noroviral infection was to blame for 48 gastroenteritis cases on this ship. Microbiological results demonstrated that transmission occurred from person-to-person. Continuing outbreaks on this ship demonstrated the need for efficient disinfection strategies to prevent this virus.

Models that describe the global spread of diseases such as influenza, severe acute respiratory syndrome (SARS), and tuberculosis (TB) consider international airports to be systems that support the spread of disease. A study done in 2000 examined information posted in the Official Airline Guide. The Official Airline Guide is a travel news, data, and ranking service that provides information of all local airline and airports in any major city. Research suggests that even a small number of airports spread through a relatively small number of cities may capture enough information to describe the global spread of disease like influenza


Cruise vessel health :

General: Viruses are extremely tiny infectious agents that are only able to live inside a cell, and are the leading cause of major outbreaks on cruise vessels. The Centers for Disease Control and Prevention (CDC) warns that most viruses are associated with cruise ships due to close living quarters, unsanitary precautions, and infected passengers. Passengers touching many surfaces in concentrated areas increase the chances of a person catching a virus. The Vessel Sanitation Program (VSP) works to help stop the spread of viruses onboard. The CDC reports that in the past 10 years, the Norovirus, Legionnaire's disease, and vector-transmitted diseases were most commonly contracted aboard cruise ship vessels. The VSP encourages travelers to learn how these viruses are transmitted, understand the health consequences, and be familiar with prevention and treatment.

Norovirus: Noroviruses (previously known as Norwalk-like viruses) are a group of viruses that affect the stomach and intestines. They may cause gastroenteritis, an inflammation of the stomach and the large intestines, and may be contracted at any age. The symptoms of noroviral infection can sometimes be misdiagnosed as food poisoning. This human pathogen results in over 200 million annual infections worldwide. Outbreaks occur more often where there are more people in a small area, such as aboard cruise vessels. Noroviruses are found in the stool or vomit of infected people and on infected surfaces that have been touched by ill people and are highly contagious. The incubation period, the development of an infection between the time the pathogen enters the body and the time the first symptoms appear, is usually 24 to 48 hours after first exposure to the virus. Signs and symptoms usually last one to five days. The diversity within noroviral infection genus makes it difficult to control.

Transmission: Noroviral infection is highly contagious, so transmission can easily happen. One of the most common means of transmission is through eating contaminated food or drinking water. In May 2004, the VSP investigated an outbreak of norovirus gastroenteritis onboard a cruise ship sailing in Alaskan waters to identify a common food source item that caused the outbreak. In summer 2006, several cruise-related viral gastroenteritis outbreaks were reported in Europe. Two of these occurred on a river cruising vessel and were linked to tap water. This virus is transmitted by touching objects or surfaces that are contaminated and then touching one's own mouth, nose or eyes, or by person-to-person transmission, such as shaking hands. It may also be transmitted by a lack of hygiene, such as keeping hands clean after using the bathroom or changing diapers, and then preparing or eating foods.

Symptoms: The most common symptoms of noroviral infections are vomiting, loose stool, and abdominal cramps. Other symptoms include low-grade fever, chills, headache, muscle aches, nausea, and fatigue. Sometimes infected people show no symptoms, but may continue to shed the virus via feces for several days, with potential for infecting others.

Prevention: The best way to prevent the spread of the norovirus is with thorough and frequent hand washing with hot water and soap. Passengers should wash hands after every trip to the bathroom, after every diaper change, and after preparing or eating food. Passengers should also avoid shaking hands of others, but use of hand sanitizers when available is recommended. The VSP and CDC work with vessel owners to develop Norovirus action plans, which include training of all employees and materials with instructions. These plans are designed to stop person-to-person transmission with disinfectants to kill these highly contagious pathogens. Private cabins and public areas are the places of greatest concern onboard. In addition, the CDC has created the Outbreak Prevention and Response Protocol (OPRP) to help control and prevent Norovirus transmission. The OPRP uses code yellow and code red to distinguish the level for threat of possible infection. In the case of a code yellow or code red, the vessel's staff takes the appropriate actions, such as isolating passengers in cabins, using disinfectants, and evaluating passengers for symptoms. After the ship has returned to normal operations, a meeting is held to review which procedures went smoothly and which need modification.

Treatment: There is no treatment for Norovirus, but passengers who exhibit the symptoms of the virus should be evaluated by a medical professional. Treatment also focuses on alleviating symptoms while the body fights the virus. Because there is a chance that dehydration can occur, patients are often given fluids. Other treatment options include rest, abstaining from food for several hours and then slowly re-introducing mild foods, and avoiding foods and drinks that could upset the stomach or contribute to dehydration, such as caffeine and alcohol.

Legionnaires' disease: Legionnaires' disease is a serious and potentially fatal type of lung infection caused by a type of bacteria called Legionella. The bacteria got its name in 1976, when a group of American Legionnaires contracted it at a convention in Philadelphia, during which 34 of 221 persons died. Although this type of bacteria existed before 1976, since then, detection of Legionnaires' disease has increased; each year, between 8,000 and 18,000 people are hospitalized with Legionnaires' disease, and in the United States it continues to be a public health concern on passenger ships. The Legionella bacteria are found naturally in the environment, usually in water. Because they thrive in warm, moist areas, they may be present in hot tubs and air-conditioning systems. People over the age of 65 have the highest risk for contracting Legionnaires' disease, as do smokers and those with lung deficiencies and weak immune systems. Detection of the disease is confirmed with urine and blood tests. Most of the time, patients can be successfully treated with antibiotics, and healthy people usually recover completely.

Transmission: Legionnaires' disease is contracted by breathing water vapor, such as steam from a hot tub that has been contaminated with the bacteria. It cannot be spread from person to person. This disease can easily be transmitted to passengers with weak immune systems aboard cruise vessels with contaminated water systems. Drinking water, bathing water, spas and pools, and even air conditioning units within cabins may be contaminated. Pontiac Fever, a flu-like illness, may occur after contraction of Legionella bacteria. In January 2003, two cases of Legionnaires' disease on cruise ships were reported to the National Epidemiological Surveillance of Infectious Diseases (NESID). One patient, a 70 year-old male heavy smoker with mild emphysema, contracted the disease in the ship's indoor spa. Another patient on the same ship was a 73 year-old female. Environmental investigation revealed that absorbent natural stones in the filters of the spas had harbored bacteria that transmitted Legionnaires' disease.

Symptoms: The symptoms of Legionnaires' disease are similar to the symptoms of pneumonia. They include high fever, chills, cough, muscle aches, and headaches, and usually begin 2-14 days after exposure to the bacteria. Gastrointestinal symptoms such as diarrhea are also common. A milder form of the infection caused by the same bacteria is Pontiac Fever. Symptoms include a fever, headaches, and muscle aches, and usually subside after 2-5 days with no treatment. Most patients who have Legionnaires' disease need chest X-rays to check for pneumonia.

Prevention: Cigarette smoking seems to be the most common risk factor in contracting this type of bacteria, so it is important for patients to quit smoking. Avoiding this disease can be difficult because it is spread through the environment, and not through personal contact. Demanding diligent disinfecting is a great form of preventative measure. Passengers should learn the history of the vessel on which they plan to travel and ask questions about air conditioning maintenance, disinfection of spas and pools, and history of outbreaks onboard. The VSP also requires that all vessels should disinfect all showerheads every six months to prevent the growth of Legionella bacteria.

Treatment: Antibiotics are the most effective way to treat Legionella bacteria.

Insect and rodent diseases: Minimizing the risk of vectors that cause diseases, such as insects and rodents, is also important. Mosquitoes, rats, mice, flies, and bedbugs are all potential transmitters of disease. Rats and rodents may be vectors of many diseases, such as rat bite fever and salmonella. The most common vector-transmitted disease is malaria, which is spread by mosquitoes and may be fatal.

Transmission: Ports pose the greatest risk factor to vessels becoming contaminated with disease vectors because they are constantly receiving deliveries and managing supplies from many other ports. Food items also attract many species of pests and parasites. Mosquitoes transmit malaria parasites to humans, in which the parasites attack the blood. Over one million people die from malaria each year because there is no vaccine. The mosquito carries the disease from one human to another. Also, many cases are attributed to travelers returning from parts of the world where malaria is prominent, such as Africa. Rat bite fever is also an infectious disease that could be a risk factor for travelers on unmaintained vessels. Rats or other rodents may become infected with either Streptobacillus moniliformis or Spirillum minus. Humans may become infected when either scratched or bitten by the infected rat, or when ingesting food or drink that has been contaminated with rat feces.

Symptoms: Typically, symptoms of malaria begin 10 days to four weeks after the initial mosquito bite, although they may appear as early as eight days or as late as one year. Symptoms include asymptomatic infections, fever, chills, sweating, headaches, muscle pain, anemia, and kidney failure. The severity of the symptoms depends on several factors, such as the species of infecting parasite and the patient's acquired immunity and genetics. Fever in the first week of travel to a malaria-risk area is unlikely to result from malaria, but travelers who feel ill should seek immediate medical care. Symptoms of Rat bite fever occur 2-10 days after transmission. The most common symptoms include chills, a fever, vomiting, headache, and muscle and joint pain.

Prevention: Prevention is based on avoiding exposure to mosquitoes and taking antimalarial drugs if traveling to areas where malaria is common, such as Africa. There are several types of antimalarial drugs, such as doxycycline, mefloquine (Lariam©), chloroquine, and the combination of atovaquone and proguanil (Malarone©). Doxycycline is the least expensive anitmalarial drug. It is good for last minute travelers because the drug is started one to two days before traveling to an area where malaria transmission occurs. It is taken daily, but it cannot be taken by women who are pregnant or by children under eight years of age. It may upset the stomach and increase sun sensitivity. Chloroquine is a drug that is good for long trips because it is taken weekly. It is not good for a last minute traveler because it needs to be started 1-2 weeks prior to travel. It may also exacerbate psoriasis. The VSP recommends that cruise vessels use an Integrated Pest Management Plan, which involves training crew, monitoring areas of the ship that attract pests, surveillance, and the use of pesticides. The VSP encourages documentation of all items entering the ship for the presence of vermin. Vessels also use traps, glue boards, and bait stations onboard to catch insects and rodents. There are many things that passengers should do to prevent getting Rat bite fever, such as avoiding contact with rats or rat dwellings, hand-washing, and avoiding hand-to-mouth contact.

Treatment: In many cases, medication or the immune system eventually helps stop the infection. The CDC recommends that treatment be guided by three main factors: the infecting Plasmodium species, the clinical status of the patient, and the drug susceptibility of the infecting parasites as determined by the geographic area where the infection was acquired. The drugs used for prevention are also used for treatment. These drugs are active against the parasite that forms in the blood. Other drugs that are used include Fansidar© and Lariam©. Fansidar© may have severe or fatal side effects. This drug must be discontinued if there is the appearance of a skin rash or occurrence of active bacterial or fungal infections. Lariam© was invented by the U.S. Army and is routinely given to soldiers overseas. Lariam© may cause neuropsychiatric adverse effects. Rat bite fever can be treated with antibiotics. Penicillin is the most recommended antibiotic, but erythromycin may be prescribed, as well.

Salmonella : Salmonella are bacteria that cause infection. Salmonella are a group of bacteria that may cause diarrheal illness in humans. The illness usually lasts 4- 7 days, but in more severe cases it may be fatal. The elderly, infants, and people with weak immune systems are more likely to have severe cases. The bacteria live in the intestinal tracts of humans and animals, including birds.

Transmission: Salmonella are transmitted to humans by eating foods contaminated with animal feces. The contaminated foods usually look and smell normal and are often of animal origin, such as beef, poultry, milk, and eggs. However, any type of food may become contaminated. Food may also become contaminated by the hands of an infected food handler onboard who did not wash his or her hands with soap after using the bathroom.

Symptoms: Most persons infected with Salmonella develop diarrhea, fever, and abdominal cramps after infection. In some cases, the diarrhea may be so severe that the passenger needs to be hospitalized. Some people may develop Reiter's syndrome, which leads to pain in their joints, irritation of the eyes, and painful urination. This can last for months and sometimes years, and can lead to arthritis.

Prevention: There is no vaccine to prevent Salmonella poisoning. Passengers should avoid eating raw or undercooked foods. Food handlers should avoid cross-contamination of foods by keeping uncooked meats from produce and cooked foods, and hand-washing between handling different food items. Infected people should avoid preparing food and pouring water for others.

Treatment: Salmonella infections can usually resolve in days without treatment. Oral fluids are recommended for dehydration. Antibiotics, such as ampicillin or ciprofloxacin, are used if the infection spreads to the intestines.

Seasickness: Seasickness is a form of motion sickness caused by the motion of a floating platform, such as a ship, boat, or raft. Seasickness is characterized by nausea and, in extreme cases, vertigo, which is a balance disorder. It is brought on by the rocking movement of a ship or boat, and visual confusion when objects move with the ship. The severity of seasickness is influenced by the irregular pressure of the bowels against the diaphragm as they shift with the rising and falling of the ship.

Symptoms: Symptoms of seasickness include headaches, vertigo, nausea, pale and moist skin, increased saliva, constipation, alteration of sense and smell, and muscular relaxation.

Prevention: Passengers should avoid alcohol, fat and spicy foods to prevent seasickness. They should also avoid small spaces, participate in onboard activities to occupy the mind, stay in fresh air and take deep breaths, drink plenty of water, and get a good night's sleep the day before boarding.

Treatment: Over-the-counter medications are available, such as Dramamine©. Ginger capsules or crystallized ginger is also recommended for settling the stomach. Passengers experiencing seasickness should try to focus their eyes on the fixed horizon. They may also try lying down on their backs and closing their eyes.

Air travel health :

General: Almost two billion people travel aboard commercial airlines every year, making it essential that health care providers are aware of the potential health risks linked to air travel. Environmental and physiological changes during routine commercial flights may lead to mild hypoxia, an oxygen deficiency, which can intensify chronic medical conditions or trigger medical events while in flight. Medical kits, defibrillators, and tele-medical ground support are always available to assist flight crew and volunteering physicians in the case of emergency. The most common air travel illnesses are related to changes in air pressure, humidity and oxygen concentration, relative immobility during flights, and close proximity to other passengers who may have communicable diseases. Ventilation systems may also spread highly contagious pathogens onboard. Passengers with pre-existing medical conditions may be at higher risk than healthy passengers.

Tuberculosis: Tuberculosis (TB) is a disease caused by the bacterium Mycobacterium tuberculosis. TB bacteria can attack any part of the body, often affecting the lungs, kidney, spine, and brain, though not everyone infected becomes sick. If not treated properly, TB may be fatal, and almost a century ago it was the leading cause of death in the United States. People with weak immune systems are at a greater risk of contracting active TB, in which the bacteria begin to multiply and destroy bodily tissue. Latent TB occurs when the TB germ has entered the body, but no sign or symptoms have occurred. People who have latent TB infection do not feel sick or show symptoms, and cannot spread TB to others, but may develop full-blown TB. Most patients with latent TB will take anti-tuberculosis medication to prevent active TB from developing.

Transmission: TB bacteria are released from person to person. They spread through the air when an infected person coughs, sneezes, or breathes. TB bacteria are usually lodged in the lungs and throat, which makes transmission easy. The risk of contracting TB on commercial flights is relatively low, but longer flights pose a greater risk of infection. Most reports show that passengers who contracted the disease in-flight were in close proximity, usually sitting within 1-4 rows of an infected passenger.

Symptoms: Symptoms of TB may vary, depending on the location of bacteria in the body, but may include an extremely bad cough, chest pain, coughing that produces blood or mucus, fatigue, loss of appetite, chills, fever, and night sweats. Those with latent TB typically do not show symptoms or feel any sign of sickness.

Prevention: Healthcare professionals suggest immediate medical consultation in the presence of these symptoms if TB is suspected. A full physical exam and annual Mantoux testing, a skin test to check for TB, is necessary to determine if the patient has active or latent TB. In general, tuberculosis is preventable, particularly in people with strong immune systems. To prevent TB transmission during air travel, air quality and ventilation must be maintained. Planes recycle air through a series of filters 20- 30 times per hour. Newer aircrafts recycle air through high-efficiency particulate air (HEPA) filters, similar to those used in hospital respiratory isolation rooms. These filters capture bacteria and large viruses to prevent transmission. Individuals with active TB are advised to be quarantined because TB is highly contagious. Before the government issued the public health "Do Not Board Plan" (DNB) in June 2007, which gives airport authorities the right to deny susceptible passengers from boarding, CDC Quarantine Station officers worked directly with airlines and health departments to prevent persons known or suspected of having communicable diseases that posed serious threats to fellow passengers from traveling on commercial flights. CDC data from 2007 to 2008 indicated that the CDC received requests for the quarantine of 42 passengers on the DNB list, all of whom were suspected of having or were confirmed with TB. BCG, or Bacille Calmette-Gu©rin, is a vaccine for tuberculosis (TB) disease. BCG is used in many countries, like Japan, with a high prevalence of TB to prevent childhood tuberculosis meningitis. However, BCG is not generally recommended for use in the United States because of the low risk of infection with tuberculosis. There is also the potential risk of side effects to the vaccination, such as a high fever, chills, flu-like symptoms, nausea, increased sensitivity to light, headache, difficulty urinating, and diarrhea or constipation. The BCG vaccine should be considered only for selected persons who meet specific criteria and in consultation with a TB expert.

Treatment: Patients who have active TB are usually treated with four antibiotics, including isoniazid (Nydrazid© or INH), rifampin (Rifadin©), ethambutol (Myambutol©), and pyrazinamide. This regimen may change if susceptibility tests later show some of these drugs to be ineffective. Depending on the severity of the disease and whether there is drug resistance, one or two of the four drugs may be stopped after a few months. If a positive TB test is encountered, but not active disease, a doctor may recommend preventive drug therapy to destroy dormant bacteria that might become active in the future. The individual will likely receive a daily dose of isoniazid. For treatment to be effective, the individual usually takes isoniazid for 6-9 months. Long-term use can cause side effects, including the life-threatening liver disease hepatitis. A doctor will monitor the individual's liver function closely while taking isoniazid. It is best to avoid using acetaminophen (Tylenol©) and avoid or limit alcohol while taking isoniazid, due to an increase in liver problems.

Influenza: Influenza is a highly contagious virus, especially for people in enclosed, poorly ventilated spaces. Commonly referred to as the flu, influenza is a contagious infection of the respiratory system caused by viruses, including influenza types A, B, and C. Avian (bird) flu is a type of A virus. Type A viruses most commonly affect adults and are the most severe, while type B viruses typically affect children and may also be severe. Type C may cause very mild illness, usually in children, but it does not have the potential for severe public health impact associated with types A and B.

Transmission: Influenza is transmitted through the air in tiny droplets when infected people cough, sneeze, or talk. Others are then exposed to the virus through inhalation, or by contact with objects, such as door handles, railings, telephones, and other contaminated surfaces. Infection may occur when the virus is then transferred to the eyes, nose, or mouth. An influenza pandemic (an epidemic that is geographically widespread; occurring throughout a region or even throughout the world ) occurs when a new strain of influenza A virus emerges for which there is little or no immunity in the human population. The new virus then begins to cause serious illness and spreads easily from person-to-person worldwide. The ventilation filters in aircrafts are able to catch the droplets that carry the virus and prevent onboard spread. Transmission of influenza on airplanes is usually associated with passengers sitting 2-3 rows from the infected person.

Symptoms: Mild cases of flu have symptoms that are very similar to the common cold, including sneezing, nasal drainage, stuffy nose, sore throat, and low fever. Symptoms usually appear suddenly, and in more severe cases, include fever of 101 degrees Fahrenheit (©F) or above, cough, muscle aches, pains, headache, sore throat, chills, sweating, loss of appetite, fatigue and malaise. Fever and body aches may last 3-5 days, and cough and lack of energy may last for two weeks or more. Most adults recover within 1-2 weeks, but the elderly and those with compromised immune systems, such as HIV/AIDS or cancer patients, may feel weak and be debilitated for several weeks after the infection has gone.

Prevention: Crew and personnel on ships and aircrafts are trained to identify and monitor any suspicious symptoms that travelers may have. During an influenza pandemic, local and state health authorities will heighten surveillance at airports. In these cases, airlines distribute travel health-alerts on commercial flights, and have the authority to quarantine infected passengers and crew. The CDC works closely with the World Health Organization (WHO) to monitor all reported outbreaks of influenza, and the U.S. Department of Health and Human Services will notify local airports and healthcare providers. If the level of transmission is high, flights may be canceled.

Treatment: Healthcare professionals recommend bed rest, liquids, and proper nutrition for rapid recovery and to prevent dehydration (fluid loss). Medical treatment may not be necessary unless symptoms persist for more than a few weeks or are severe. Over-the-counter (OTC) medications may reduce the duration and discomfort of symptoms, including body aches and pains, congestion, runny nose, and cough. These products are available in formulas that treat symptoms separately, and in combination. Antibiotics are not effective against the flu. Antibiotics are medicines that kill bacteria and are, therefore, only useful for treating bacterial infections. The flu is a viral infection, not bacterial.

Severe acute respiratory syndrome (SARS): Severe acute respiratory syndrome (SARS) is a contagious respiratory infection that may be fatal. The risk of transmission while onboard an aircraft is very low, but cases have been reported. The World Health Organization (WHO) lists that the most recent reported cases of SARS were found in Canada, Singapore, China, and Vietnam. The WHO also recommends that travelers educate themselves about the virus and take in-flight precautions, such as those mentioned below.

Transmission: SARS is highly contagious and spreads from person to person through airborne mucus droplets. Mucus droplets may enter the air when an infected person coughs, sneezes, laughs, or talks. If another individual inhales these mucus droplets or particles, he or she may become infected. SARS may also be spread when a person touches contaminated objects, such as airplane magazines, overhead compartments, railings, and buttons, and then touches one's face.

Symptoms: Experts believe that patients are only contagious when symptoms are present and that the risk of spreading SARS is highest the second week after symptoms develop. The U.S. Centers for Disease Control and Prevention (CDC) recommends that individuals with SARS avoid public areas for at least 10 days after symptoms are gone. Between 2-10 days after exposure to the SARS virus, patients typically develop a temperature of 100.4oF or higher. Symptoms typically include soreness, chills, muscle soreness, headache, and general feeling of discomfort.

Prevention: Individuals should try to learn about SARS before planning trips to areas known to have had SARS outbreaks, such as China, Taiwan, Singapore, and Canada. The CDC and WHO keep updated information about these locations on their websites. In addition, patients should talk with their health care providers before traveling to such areas. To reduce the chance of contact with a pathogen that is spread through aircraft vents over passenger seats, consider turning the vent off. Passengers should also wash their hands as often as possible, avoid touching the face, and consider using antibacterial wipes or gels. If a person with possible SARS flies on an airplane while ill, the CDC will work with the state and local health authorities to monitor all travelers for 10 days for possible SARS symptoms.

Treatment: Eating a well-balanced diet and striving for eight hours of sleep a night may boost the immune system, which helps the body fight infections. Patients who are diagnosed with SARS are usually prescribed antiviral drugs.

Deep vein thrombosis and blood vessel disorders: Deep vein thrombosis (DVT) is an under-diagnosed, preventable condition that occurs when a blood clot forms in a large vein. These clots develop in the leg, thigh, arm, and pelvis. DVT can happen to any person and may be fatal. DVT is preventable and treatable if diagnosed early and correctly.

Transmission: DVT is not a transmittable or communicable disease. It is a condition that can happen to almost any person. DVT occurs when a blood clot forms in a large vein, usually in the leg, and may travel into the lung, causing a pulmonary embolism. Pulmonary embolism is a blockage of the pulmonary artery, usually occurring when a blood clot becomes dislodged from its site and travels to the arterial blood supply of one of the lungs. Factors that increase the risk of developing DVT include fracture, severe muscle injury, surgery, confinement, limited movement, family history, obesity, smoking, and increased estrogen. Passengers onboard aircrafts are at a greater risk for getting DVT because of sitting too long in one position or having limited movement.

Symptoms: The most common symptoms for DVT are swelling, pain and/or tenderness in the legs, and redness of the skin. Symptoms of a pulmonary embolism include shortness of breath, rapid breathing, chest pain, cough, and possibly sudden death in more severe cases.

Prevention: The Centers for Disease Control and Prevention (CDC) recommends that passengers should get up and walk around the cabin when sitting for long periods. The CDC also provides leg exercises to perform while sitting, such as raising and lowering the heels of the foot while keeping the toes on the floor, and tightening and releasing the leg muscles. Wearing loose-fitting clothes can also help prevent DVT. The CDC also suggests drinking plenty of water and avoiding alcohol and caffeine.

Treatment: Medication is used to prevent and treat DVT. The most common medicines are blood thinners. Compression stockings are sometimes recommended to prevent DVT and relieve pain and swelling. In more severe cases, the clot may need to be removed surgically. Emergency care in a hospital is necessary to treat a pulmonary embolism. There are medications, such as thrombolytics that can dissolve the clot, and anticoagulants to prevent more clots from forming.

Panic attacks/anxiety: Panic attacks associated with flying are extremely common. It may happen to anyone at anytime and without warning. Anxiety is a psychological and physiological disorder that creates unpleasant feelings associated with fear or worry. The body reacts as if it is dealing with a possible threat. They are treatable and not fatal.

Symptoms: The most common symptoms associated with anxiety or panic attacks are heart palpitations, shortness of breath, sweating, chest pain, dizziness, fatigue, headaches, or nausea. Blood pressure and heart rate are increased. A person experiencing a panic attack might feel as if they are about to die or pass out. Panic attacks are sometimes confused with heart attacks.

Prevention: There are many different preventative measures that one can do to prevent panic attacks. Passengers that are prone to having anxiety or panic attacks should avoid stimulants, such as caffeine, diet pills, and smoking. Learning how to control one's breathing will help relieve symptoms of panic attacks. Meditation will also help with muscle relaxation. Passengers should try to keep their mind occupied by reading a book or using in-flight entertainment. Lastly, learning about panic will help relieve distress. Gaining knowledge about anxiety and panic disorder will help distinguish them from other illnesses or health problems.

Treatment: Antidepressants and benzodiazepines are used to treat panic attacks. Antidepressants take time to build up in the body, so it is important to take them continuously for several weeks before traveling. Benzodiazepines are anti-anxiety drugs that act quickly, such as Xanax©. They provide rapid relief of symptoms, but they may have side effects, such as sleepiness. Benzodiazepines are highly addictive, so they should be used with caution.

Environmental effects: The main environmental concerns associated with airplanes are climate change, ozone reduction, regional pollution from emissions of nitrogen oxides, and local pollution of noise and decreased air quality caused by aircrafts. During flight, aircraft engines emit carbon dioxide, nitrogen oxides, sulfur, water vapor, and hydrocarbons. These emissions alter the chemical composition of the atmosphere. Many of the emissions from aircraft change the absorption of solar radiation and the absorption and emission of thermal radiation, which may affect climate. Aircraft emissions of greenhouse gases, such as carbon dioxide, act to warm the surface of the earth globally. Liquid hydrogen as a fuel may clearly remove the carbon dioxide effect at the point of emission.

Wildlife effects: Airplanes have to work to keep wildlife away from planes in order to prevent disasters. According to the Federal Aviation Administration (FAA), there were 5,622 bird strikes that were recorded in the United States in 2008. A bird strike happens when there is a collision between an airborne animal and an airplane. The most recent and well-known bird strike happened in January of 2009, when a US Airways plane crashed into the Hudson River with 155 passengers. The pilot reported a double bird strike, which caused the plane to lose its engine power and crash into the river. Luckily, all passengers survived.

Airport personnel run patrols on the outfield and runway to look for wildlife or foreign objects in order to help prevent possible bird strikes. The FAA declares that airports must conduct wildlife hazard assessments and prepare a Wildlife Hazard Management Plan. This plan provides measures to alleviate or eliminate wildlife hazards, identifies persons with authority for implementing the plan, provides priorities for needed habitat modification, and provides wildlife control measures. To prevent wildlife hazards, the FAA suggests that airports control vegetation, fill up water sources, and use wildlife harassment tools, such as air guns, dogs, and traps.


General: The Centers for Disease Control and Prevention (CDC) continues to help prevent and control the spread of communicable disease on cruise vessels and aircrafts.

The collaboration of the CDC and cruise ship industry proactively protects the health of travelers. The Vessel Sanitation Program (VSP), created by the CDC, has instituted and automated the web-based Gastrointestinal Illness Surveillance System to receive and process vessel reports.

Reducing the risk of infections: The Centers for Disease Control and Prevention (CDC) continues to implement highly developed public health measures to prevent, identify, and control diseases associated with food, water, environmental contamination, and person-to-person transmission

The Secretary of the Department of Health and Human Services (HHS) has statutory responsibility for preventing the introduction, transmission, and spread of communicable disease in the United States. Health and Human Services are prepared to work with travel industry partners to ensure that airplane and cruise ship captains and crew are familiar with procedures for identifying and managing arriving ill passengers. They are also working on coordinating with other countries and the World Health Organization (WHO) to prevent the spread of new strains of influenza by international travel.

Decreasing pollution: The Environmental Protection Agency (EPA) evaluates new and existing chemicals and their risks to try and prevent or reduce pollution before it gets into the environment. The EPA also manages a variety of environmental stewardship programs that encourage airports and vessel owners to reduce and prevent pollution. The EPA is also investigating alternative fuel options for both cruise vessels and aircrafts

The Federal Aviation Administration (FAA) has modeled the Next Generation Air Transportation system, which is a plan to modernize the National Airspace System through 2025. It is currently working with the National Aeronautics and Space Administration (NASA) and the National Oceanic and Atmospheric Administration (NOAA) to account for trade-offs between different control strategies and policies to fill in knowledge gaps concerning aircraft impacts on greenhouse gas emissions.


This information has been edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (

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