When people travel, their bodies take some time to adapt to a new destination, especially to food and water. In some foreign countries lax sanitary conditions exist, which may even compromise a traveler's health. Thus, the risk of getting sick is often increased when traveling. Drinking water in some developing countries may contain bacteria, parasites, and viruses that can cause traveler's diarrhea (TD). Traveler's diarrhea, one of the more common ailments experienced during traveling, is the occurrence of multiple loose bowel movements in someone traveling to an area outside their usual surroundings, usually from temperate industrialized regions to tropical areas. The cause is almost always bacterial or viral infection acquired through ingesting contaminated food or water.
Every year Americans travel to international locations. Some of these foreign regions make American travelers more susceptible to diseases and medical conditions that adversely affects their health. For instance, diarrhea is a disorder caused by numerous microorganisms such as bacteria, protozoans, and viruses. It brings about water and electrolyte loss within the body, which leads to dehydration and in some cases death. It is estimated that 20% to 50% of the 12 to 20 million travelers going from temperate industrialized countries to the tropics have their health compromised and, as a consequence, could develop TD. Fortunately, most of these episodes are brief. Nevertheless, about 40% of those affected need to rearrange their schedule, and 20% may be ill enough to remain in bed for some days.
The chance of winding up with TD is directly related to the destination; only about 8% of individuals visiting an industrialized country are affected, whereas at least half of those traveling to nonindustrialized regions become ill. It is also clearly related to the number of potentially contaminated foods or beverages consumed. Attention to recommended guidelines regarding food safety and sanitation can greatly decrease the risk of infection.
The health of travelers can also be compromised by other medical condition. The U.S. Centers for Disease Control and Prevention (CDC) lists numerous diseases that can affect humans while traveling. Its list is contained under its website heading “Diseases Related to Travel.” The CDC list is lengthy. Below are a few of the more commonly known travel diseases:
Cholera is an acute and often fatal intestinal disease that produces severe gastrointestinal symptoms. Caused by the bacterium Vibrio cholera, cholera is rarely present in industrialized countries. In fact, it was mostly absent from the United States during the twentieth century and into the twenty-first century. However, as of the early 2000s, cholera was still common in many parts of the world, including the Indian subcontinent and sub-Saharan Africa.
In another instance, malaria is caused by parasitecarrying mosquitoes. People with malaria often have flu-like symptoms, such as chills and fever. If left untreated, malaria can cause serious complications, including death. According to the CDC, in 2016, about 216 million cases of malaria occurred in the world. Of those, 445,000 people died, with over 91% of them dying in Africa.
Typhoid fever is a life-threatening illness caused by the bacterium Salmonella enterica serotype Typhi. It is usually transmitted through water or food that is contaminated by feces. The CDC estimates that about 22 million cases occur worldwide each year, with an associated 200,000 deaths. In the United States, about 300 cases occur each year, with most of those occurring among recent travelers abroad. The highest risks of getting typhoid fever occur among those people traveling to southern Asia, eastern Asia, Southeast Asia, Africa, the Caribbean, Central American, and South America.
The CDC provides valuable information for travelers with regards to health alerts for common diseases found around the world. Its website “Travel Notices” provides important current information.
The causes and symptoms of diseases caught by travelers are much varied due to the high number of such ailments that occur around the world. Some of the more common causes and symptoms are discussed below.
Causes of the diseases commonly associated with traveling vary depending on the specific medical problem. For accurate information on causes and their symptoms for diseases associated with traveling, people ought to refer to the CDC website “Diseases
Related to Travel.” Bacterial infections are the most common cause of traveler's diarrhea. Viruses and occasional parasites also can be the cause. As for the bacteria involved, toxin producing types of E. coli (called enterotoxigenic) account for approximately 40% to 60% of cases, with Campylobacter and Shigella each reported in at least 10% of cases. In some studies, Campylobacter has accounted for almost half of the attacks, especially during cooler seasons of the year. The cause can vary depending on several factors, including the season and country visited. More than one organism can be found in 15% to 30% of cases, while none is identified in up to 40% of cases worldwide.
Rotaviruses and a parvovirus called Norwalk agent also are responsible for TD. Giardia is probably the most common parasite identified, although amoebas (Entamoeba histolytica), Cryptosporidium, and Cyclospora are found frequently.
Symptoms associated with TD usually start within a few days after arrival but can be delayed for as long as two weeks. Illness lasts an average of three to five days but sometimes longer. Cramping abdominal pain, lack of appetite, and diarrhea are the main complaints. In approximately 10% of patients, diarrhea turns bloody. Fever develops in about half of the cases. The presence of bloody bowel movements and fever usually indicates a more severe form of illness and makes Shigella a more likely cause. Medications that decrease the motility or contractions of the intestine, such as loperamide (Imodium) or diphenoxylate (Lomotil), should not be used when fever or bleeding occur.
Diarrhea varies from a few loose stools per day to ten or more. Dehydration and changes in the normal blood pH (acid-base balance) are the main dangers associated with TD. Signs of dehydration can be hard to notice, but increasing thirst, dry mouth, weakness or lightheadedness (particularly if worsening while standing), or a darkening/decrease in urination are suggestive. Severe dehydration and changes in the body's chemistry can lead to kidney failure and become life-threatening.
Another potential complication is toxic megacolon, in which the colon gradually stretches and its wall thins to the point where it can tear. The presence of a hole in the intestine leads to peritonitis and is fatal unless quickly recognized and treated.
Other complications related to TD can involve the nervous system, skin, blood, or kidneys.
Some travel-related illnesses may not show themselves for days, weeks, months, or even years after travelers return to the United States. In all cases, medical professionals will diagnosis a traveler with a medical problem according to the presence of specific symptoms, the destination and region of the world traveled to (some diseases are more common in certain parts of the world than they are in others), and other related factors. They will want to know about the weeks and months leading up to travel, during travel, and those following travel. A complete physical examination and gathering of a comprehensive history of the patient will be conducted, along with any laboratory tests that are deemed necessary. In some cases, appropriate health officials may be notified, such as for measles, tuberculosis, and viral hemorrhagic fever. Further, a physician familiar in travel-related illnesses may be called in under special circumstances. For example, travelers to a tropical location may need a tropical medicine specialist to evaluate their illness.
According to the CDC, the following should be evaluated by the medical professional when diagnosing returning travelers with illnesses:
With regards to TD, the occurrence of diarrhea in an individual while traveling is very suggestive of traveler's diarrhea. Although there are other possible causes, these are less likely. In most instances, the specific organism responsible for the symptoms does not need to be identified, and the majority of patients need only rest and treatment to avoid potential complications.
When patients develop fever or bloody diarrhea, the illness is more serious and a specific diagnosis is needed. In those cases, or when symptoms last longer than expected, stool samples are obtained to identify the organism.
For this purpose, laboratories can either try to grow (culture) the organism or identify it with high-powered microscopes (electron microscopy) or with the use of special tests or stains. These can show parasites such as Giardia, Amoeba, Cryptosporidium and others in freshly obtained stool specimens. New techniques that involve identification of DNA (formally known as deoxyribonucleic acid; the characteristic material that controls reproduction and is unique for all individuals) of the various organisms also can be used in special circumstances.
The best treatment for any diseases incurred while traveling, including TD, is prevention. Before traveling to foreign destination, individuals should schedule a visit with their family doctor or other health professional. The CDC recommends that a medical visit be set up at least four to six weeks before the trip. While there, individuals need to confirm that all vaccinations are administered that are recommended or required for travel to specific regions of the world. In many cases, it takes at least four weeks for vaccines to become effective within the body. In other cases, vaccines must be delivered gradually to the body, which may take over six weeks to complete. Which vaccinations are needed depends on a number of factors, including the destination, season of travel, age, health status, previous immunizations, and other important considerations. The CDC has three categories for vaccines: routine, recommended, and required. Routine vaccines protect people from diseases that are still common in many parts of the world but only rarely occur in the United States. The CDC provides recommended immunization schedules for adults, adolescents, children, and infants at its website.
Recommended vaccines also help to protect travelers from illnesses present in other parts of the world; however, they also prevent infectious diseases from being brought into the United States when travelers return from their trips. The CDC provides detailed information on specific destinations in the world at its website. Required vaccines are only those required by International Health Regulation. Yellow fever, for instance, is required for individuals who are traveling to some countries in sub-Saharan Africa and tropical countries of South America. The Saudi Arabian government requires a vaccination for meningococcal when individuals are traveling during the Hajj (an Islamic pilgrimage to Mecca).
In addition, individuals should discuss with their medical provider any illnesses or medical conditions that may make them more susceptible to diseases while traveling, such as diabetes or human immunodeficiency virus (HIV). People who are traveling with infants or children should be especially aware of the dangers associated with traveling to foreign countries. Women who are pregnant or breastfeeding should also be aware of such concerns.
For traveler's diarrhea, once it occurs, therapy is aimed at preventing or reducing dehydration and using antibiotics when needed. Fortunately, severe dehydration is unusual in patients with TD, but any fluid losses should be treated early with either fruit juices and clear fluids such as tea or broth, or with the recommended Oral Rehydration Solutions (ORSs) suggested by the World Health Organization (WHO). Persons traveling to known areas of infection should consult with their physician prior to departure and obtain appropriate instructions. For example, it may be advised to take along pre-prepared packets of ORS designed for easy mixing or commercial preparations such as Pedialyte, Ceralyte, and Ricelyte.
When nothing else is available, the following WHO recipe can be made up from household items and taken in small frequent sips:
A debate occurred in the medical community over the amount of salt (sodium) in the WHO preparations; some physicians explained that the content is too much for use by well-nourished persons in developed countries. Therefore, these preparations should not be used for extended periods of time without consulting a physician.
Pepto-Bismol (bismuth subsalicylate preparation) is effective in both preventing and treating TD. For treatment once symptoms begin, the drug must be taken more frequently than when used for prevention. Bismuth subsalicylate preparation (1 ounce of liquid or two 262.5-milligram tablets every 30 minutes for eight doses) has been shown to decrease the number of bowel movements and shorten the length of illness. However, there is some concern about the large doses of bismuth in patients with kidney disease; therefore, patients should check with physicians before starting this or any other therapy. Patients should be aware that bismuth can turn bowel movements black.
Rifamixin (Normix), a drug for treating traveler's diarrhea, was approved by the U.S. Food and Drug Administration (FDA) in 2010. Medications designed to decrease intestinal motility and contractions such as loperamide (Imodium), diphenoxylate (Lomotil), or others are safest when used by those without fever or bloody bowel movements. The presence of either of these symptoms indicates a more severe form of colitis.
Antibiotics are usually not prescribed, because most cases of TD rapidly improve with minimal treatment. For patients in whom symptoms are especially severe (four or more stools per day or the onset of bloody diarrhea or fever), or those with compromised immune systems, antibiotics are indicated. Individuals with less severe attacks can be treated with either antimotility medications or bismuth subsalicylate.
Choice of an antibiotic should ideally be tailored to the most likely organism and then adjusted according to results of stool cultures. Trimethoprim-sulfamethoxazole (Bactrim) or ciprofloxacin (Cipro) are the antibiotics most often prescribed, but others are also used. The type and duration of treatment continues to be revised, and it is therefore extremely important that patients check with a physician prior to beginning treatment. In many instances, an antibiotic can be combined with an anti-motility agent to provide the quickest relief.
The U.S. Centers for Disease Control and Prevention (CDC) provides a website just for travelers' health. Topics discussed at this website include health information for over 200 destinations worldwide, general information about vaccinations, the types of illnesses frequently occurring overseas, and locations of health clinics and health specialists found throughout the world. The CDC also provides “Your Survival Guide to Safe and Healthy Travel.” It gives details on how to be proactive, prepared, and protected while traveling.
Numerous CDC outbreak notices are issued around the world.
Most people who are treated promptly recover from illnesses associated with traveling. However, there are always exceptions. For instance, diagnosed cases of yellow fever result in death 5% to 10% of the time. Jaundice is an important indicator when individuals are infected with yellow fever.
Hygienic sewage disposal systems in a community, good water treatment facilities, and proper personal hygiene are the most important factors in preventing many problems occurring with travelers. Immunizations are available for travelers who expect to visit countries where known public health problems are common. Some of these immunizations provide only short-term protection (for a few months), while others may be effective for several years. Efforts are being made to develop vaccines that provide a longer period of protection with fewer side effects from the vaccine itself. For instance, an effective yellow fever vaccine exists. Called the Arilvax vaccine, it is made from a weakened form of the yellow fever virus, strain 17D. In the United States, the vaccine is given only at Yellow Fever Vaccination Centers authorized by the U.S. Public Health Service. About 95% of vaccine recipients acquire long-term immunity to the yellow fever virus.
With regards to traveler's diarrhea, the best means of prevention is avoiding foods, beverages, and food handling practices that lead to infection with the organisms that cause TD. Drinking bottled water and using bottled water for brushing teeth, eating fruits that travelers peel themselves, and eating well-cooked, hot foods can help prevent illness.
One effective means to prevent TD is liquid Pepto-Bismol; this bismuth-containing compound has been shown to be very effective in reducing the incidence of TD. Tablets are available, which are easier to carry. Two tablets four times a day is recommended, but use should continue beyond three weeks.
Antibiotics can also prevent TD, but their use is controversial, unless it is absolutely necessary to avoid infection (such as in someone on an important business trip or who has a weakened immune system). There is the tendency for bacteria to become resistant to these medications if people use them excessively, and these drugs have side effects that can be worse than the effects of TD. The benefits and risks of antibiotic treatment should be carefully weighed.
See also Altitude illness ; Cholera ; Malaria ; Meningitis ; Plague ; Tuberculosis ; Tropical disease ; Typhoid fever ; West Nile virus ; Yellow fever ; Zika virus disease .
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