Traveler's diarrhea
Encyclopedia
Traveler's diarrhea is the most common illness affecting travelers. An estimated 10 million people—20% to 50% of international travelers—develop it annually. TD is defined as three or more unformed stool
s in 24 hours passed by a traveler, commonly accompanied by abdominal cramp
s, nausea
, and bloating
. It does not imply a specific organism, but Enterotoxigenic Escherichia coli
is the most common. Most cases are self-limited and the pathogen is usually not identified.
averages about 14 days and that of cryptosporidiosis
about seven days. Certain other bacterial and viral agents have shorter incubation periods, although hepatitis may take weeks to manifest itself. Most TD cases begin abruptly.
Typically, a traveler experiences four to five loose or watery bowel movements each day. Other commonly associated symptoms are nausea, vomiting, diarrhea, abdominal cramping, bloating, low fever, urgency, and malaise, and appetite is usually low or nonexistent.
Blood or mucus
in the diarrhea, abdominal pain, or high fever heralds a more serious cause, such as cholera
, characterized by a rapid onset of symptom
s including weakness, malaise
, and torrents of watery diarrhea with flecks of mucus (described as "rice water" stools). Dehydration is a serious consequence of cholera; death may (rarely) occur as quickly as 24 hours after onset.
Infectious agent
s are the primary cause of travelers' diarrhea. Bacterial enteropathogens
cause approximately 80% of cases. Viruses and protozoans account for most of the rest.
The most common causative agent isolated in countries surveyed has been enterotoxigenic Escherichia coli
(ETEC). Enteroaggregative E. coli
is increasingly recognized and many studies do not look for this important bacterium. Shigella
spp. and Salmonella
spp. are other common bacterial pathogens. Campylobacter
, Yersinia
, Aeromonas
, and Plesiomonas spp. are less frequently found. Some bacteria release toxin
s which bind to the intestinal wall and cause diarrhea; others damage the intestines themselves by their direct presence.
While viruses are associated with less than 20% of adult cases of traveler's diarrhea, they may be responsible for nearly 70% of cases in infants and children. Diarrhea due to viral agents is unaffected by antibiotic therapy, but is usually self-limited. Protozoans such as Giardia lamblia
and Cryptosporidium
can also cause diarrhea.
Pathogens implicated in travelers' diarrhea appear in the table at right.
A sub-type of traveler's diarrhea afflicting hikers and campers, sometimes known as wilderness diarrhea, may have a somewhat different frequency distribution of pathogens.
The most important determinant of risk is the traveler's destination. High risk destinations include developing countries
in Latin America, Africa, the Middle East, and Asia. Among backpackers, additional risk factors include drinking untreated surface water and failure to maintain personal hygiene practices and clean cookware. Campsites often have very primitive (if any) sanitation facilities, making them potentially as dangerous as any developing country.
Although traveler's diarrhea usually resolves within three to five days (mean duration: 3.6 days), in about 20% of cases the illness is severe enough to require bedrest, and in 10% the illness duration exceeds one week. For those prone to serious infections, such as bacillary dysentery
, amoebic dysentery
, and cholera
, TD can occasionally be life-threatening. Others at higher-than-average risk include young adults, immunosuppressed
persons, persons with inflammatory bowel disease
or diabetes, and those taking H2 blockers or antacids.
that develops after repeated exposure to pathogens. It is not fully clear how much exposure is needed, and to what extent the immune system can become tolerant to pathogens, but a study among expatriates in Nepal suggests that it can take seven years to develop immunity—presumably in adults who avoid deliberate pathogen exposure.
Conversely, immunity that American students acquired while living in Mexico appeared to disappear within as little as 8 weeks of cessation of exposure.
If handled properly, well-cooked and packaged foods are usually safe. Eating raw or undercooked meat and seafood should be avoided. Unpasteurized
milk, dairy products, mayonnaise and pastry icing are associated with increased risk for TD, as are foods or drinking beverages purchased from street vendors or other establishments where unhygienic conditions may be present.
Active intervention involves boiling water for three to five minutes (depending on elevation), filtering water with appropriate filters or using chlorine bleach (2 drops per litre) or tincture of iodine (5 drops per litre) in the water. The wide availability of safe bottled water makes these interventions unnecessary for all but the most remote destinations.
An ultraviolet (UV) water purification device is available commercially that allows treatment of small amounts of water at room temperature. The UV light bonds DNA thymine
rings, preventing the survival or replication of any infectious organisms in the water. UV light also kills viruses, which are not typically removed by filtration (although filtration is recommended prior to treatment if the water is visibly clouded). Other claimed advantages include no taste alteration, elimination of need for boiling, and decreased long-term cost compared with bottled water.
Other preventive measures include over-the-counter anti-diarrhea products and in certain situations, prophylactic medications and supplements. Studies show a decrease in the incidence of TD with use of bismuth subsalicylate
and antimicrobial chemoprophylaxis
.
Bismuth subsalicylate (two tablets or two ounces four times daily) will reduce the likelihood of travelers' diarrhea, but few travelers adhere to a four-times-per-day regimen because it is inconvenient. Side effects may include black tongue, black stools, nausea, constipation, and ringing in the ears (tinnitus
). Bismuth subsalicylate should not be taken by those with aspirin allergy, kidney disease, or gout, nor concurrently with certain antibiotics, and should not be taken for more than three weeks.
Though effective, antibiotics are not recommended in most situations to prevent diarrhea before it occurs, because of the risk of adverse reactions to the antibiotics, and because intake of prophylactic antibiotics may decrease effectiveness of such drugs should a serious infection occur. Antibiotics can also cause vaginal yeast infections (which many women consider a worse problem than the diarrhea). Also, antibiotics can cause a disease called pseudomembranous colitis
which results in severe, unrelenting diarrhea.
However, prophylaxis may be warranted in special situations where benefits outweigh the above risks, such as immunocompromised travelers, chronic intestinal disorders, prior history of repeated disabling bouts of traveler's diarrhea, or scenarios in which onset of diarrhea might prove particularly troublesome. Options for prophylactic treatment include the quinolone antibiotics (norfloxacin
, ciprofloxacin
, ofloxacin
, among others), and trimethoprim/sulfamethoxazole. Quinolone antibiotics may bind to metallic cations such as bismuth, and should not be taken concurrently with bismuth subsalicylate. Trimethoprim/sulfamethoxazole should not be taken by anyone with a history of sulfa allergy.
A few pathogen-specific vaccine
s have become available, and others are under development. Dukoral, an oral vaccine against Vibrio cholerae
, has demonstrated up to 43% protective efficacy against TD when one dose is given a few weeks before travel and a second a week before travel, although it is not officially approved for that indication in most countries. Several vaccine candidates targeting enterotoxigenic E. coli and Shigella are in various stages of development.
A patch-delivered travelers’ diarrhea vaccine is under development by Iomai (which was acquired by Intercell
in 2008). Results of a phase II clinical trial, published in 2008 in The Lancet, indicate significant protection from clinically significant diarrhea compared with placebo. The vaccine remains experimental, at the phase III clinical trial level, and is not yet licensed in any country.
In 2009 a research group at the University of Guelph
announced that it was working on a TD vaccine targeting Campylobacter jejuni. To date, no human clinical trials have been reported.
Travelan
is a proprietary mix of antibodies against common strains of E.Coli involved in travellers diarrhea. The manufacturer claims that the antibodies inhibit ETEC attachment to the intestinal wall, and avoid killing beneficial flora because of their specificity to ETEC strains. When taken orally before every meal, the manufacturer claims prevention of TD "in up to 93% of volunteers", but no impartial placebo-controlled studies have been published. In 2010 the product underwent an FDA recall after it "...failed to meet stability specifications when assayed at approximately 3 months after being manufactured."
Two probiotics (Saccharomyces boulardii
and a mixture of Lactobacillus acidophilus
and Bifidobacterium bifidum) have been studied as a treatment for TD. In a meta-analysis
by McFarland (2005), no serious adverse reactions were reported in 12 trials. These probiotics may offer a safe and effective method to prevent TD, but due to strain stability and survivability issues, they may not always be an appropriate choice.
Prebiotics, as an alternative, are more stable than probiotics during passage through the upper gastrointestinal tract and are able to induce antimicrobial effects principally through their selective stimulation of our own beneficial gut bacteria. However, prebiotics act mainly in the large intestine, while the infective organisms causing TD act in the small intestine. Therefore, current prebiotics (such as fructooligosaccharide
) have very limited application as preventative agents. Second generation prebiotic galactooligosaccharides
, such as B-GOS (Bimuno), have additional properties such as positive effect on immunity and direct interaction with the host gut epithelium, preventing the attachment and invasion of gastrointestinal pathogens. B-GOS was shown to result in significant reduction in the incidence and duration of TD in a study with human volunteers travelling to countries with medium to high risk of developing TD.
. Adequate fluid intake (oral rehydration therapy
) is essential to replace lost fluids and electrolytes. Clear, disinfected water or other liquids are routinely recommended for adults. Water that is purified is best, along with oral rehydration salts to replenish lost electrolytes. Carbonated water (soda), which has been left out so that the carbonation fizz is gone, is useful if nothing else is available. In severe or protracted cases, the oversight of a medical professional is advised.
or levofloxacin have been used. If diarrhea persists despite therapy, travelers should be evaluated for possible viral or parasitic infections, bacterial or amoebic dysentery, Giardia, helminths, or cholera.
and diphenoxylate
reduce the symptoms of diarrhea by slowing transit time in the gut. They should be taken as necessary to slow the frequency of stools, but not enough to stop bowel movements completely, which delays expulsion of the causative organisms from the intestines. Adverse reactions may include nausea, vomiting, abdominal pain, hives or rash, and loss of appetite. Antimotility agents should not, as a rule, be given to children under age two.
s for travelers' diarrhea contracted in various localities, such as "Montezuma's revenge", "turistas", or "Aztec two step" in Mexico
; and "Pharaoh's Revenge," "mummy's tummy," or "Cairo two-step" in Egypt
. Many other colorful synonyms exist in other regions of the world, some of which have found their way into the arts and literature. For example, Aamir Khan
titled his 2011 Hindi film Delhi Belly, after the popular Indian colloquialism.
. The name refers to Moctezuma II
(1466–1520), the Tlatoani
(ruler) of the Aztec
civilization who was defeated by Hernán Cortés
, the Spanish conquistador.
in longer expeditions. It is often due to the absence of treated water and poor hygiene. Since wilderness campsites seldom provide access to sanitation facilities, the infection risk is similar to that of any developing country. Some people reserve the name backpacker's diarrhea as a synonym for giardiasis.
Human feces
Human feces , also known as a stool, is the waste product of the human digestive system including bacteria. It varies significantly in appearance, according to the state of the digestive system, diet and general health....
s in 24 hours passed by a traveler, commonly accompanied by abdominal cramp
Cramp
Cramps are unpleasant, often painful sensations caused by muscle contraction or over shortening. Common causes of skeletal muscle cramps include muscle fatigue, low sodium, and low potassium...
s, nausea
Nausea
Nausea , is a sensation of unease and discomfort in the upper stomach with an involuntary urge to vomit. It often, but not always, precedes vomiting...
, and bloating
Bloating
Bloating is any abnormal general swelling, or increase in diameter of the abdominal area. As a symptom, the patient feels a full and tight abdomen, which may cause abdominal pain sometimes accompanied by increased borborygmus or more seriously the total lack of borborygmus.-Symptoms:The most common...
. It does not imply a specific organism, but Enterotoxigenic Escherichia coli
Enterotoxigenic Escherichia coli
Enterotoxigenic Escherichia coli is a type of Escherichia coli and the leading bacterial cause of diarrhea in the developing world, as well as the most common cause of traveler's diarrhea. Each year, approximately 210 million cases and 380,000 deaths occur, mostly in children, from ETEC...
is the most common. Most cases are self-limited and the pathogen is usually not identified.
Epidemiology
Each year 20%–50% of international travelers (more than 10 million people) develop traveler's diarrhea. It is more common in the developing world, where rates exceed 60%, than in developed countries.Signs and symptoms
The onset of TD usually occurs within the first week of travel, but may occur at any time while traveling, and even after returning home. When it appears depends in part on the specific infectious agent. The incubation period for giardiasisGiardiasis
Giardiasis or beaver fever in humans is a diarrheal infection of the small intestine by a single-celled organism Giardia lamblia. Giardiasis occurs worldwide with a prevalence of 20–30% in developing countries. In the U.S., 20,000 cases are reported to the CDC annually, but the true annual...
averages about 14 days and that of cryptosporidiosis
Cryptosporidiosis
Cryptosporidiosis, also known as crypto, is a parasitic disease caused by Cryptosporidium, a protozoan parasite in the phylum Apicomplexa. It affects the intestines of mammals and is typically an acute short-term infection...
about seven days. Certain other bacterial and viral agents have shorter incubation periods, although hepatitis may take weeks to manifest itself. Most TD cases begin abruptly.
Typically, a traveler experiences four to five loose or watery bowel movements each day. Other commonly associated symptoms are nausea, vomiting, diarrhea, abdominal cramping, bloating, low fever, urgency, and malaise, and appetite is usually low or nonexistent.
Blood or mucus
Mucus
In vertebrates, mucus is a slippery secretion produced by, and covering, mucous membranes. Mucous fluid is typically produced from mucous cells found in mucous glands. Mucous cells secrete products that are rich in glycoproteins and water. Mucous fluid may also originate from mixed glands, which...
in the diarrhea, abdominal pain, or high fever heralds a more serious cause, such as cholera
Cholera
Cholera is an infection of the small intestine that is caused by the bacterium Vibrio cholerae. The main symptoms are profuse watery diarrhea and vomiting. Transmission occurs primarily by drinking or eating water or food that has been contaminated by the diarrhea of an infected person or the feces...
, characterized by a rapid onset of symptom
Symptom
A symptom is a departure from normal function or feeling which is noticed by a patient, indicating the presence of disease or abnormality...
s including weakness, malaise
Malaise
Malaise is a feeling of general discomfort or uneasiness, of being "out of sorts", often the first indication of an infection or other disease. Malaise is often defined in medicinal research as a "general feeling of being unwell"...
, and torrents of watery diarrhea with flecks of mucus (described as "rice water" stools). Dehydration is a serious consequence of cholera; death may (rarely) occur as quickly as 24 hours after onset.
Causes
| E. coli, enterotoxigenic | 20-75% |
| E. coli, enteroaggregative | 0-20% |
| E. coli, enteroinvasive | 0-6% |
| Shigella Shigella Shigella is a genus of Gram-negative, nonspore forming, non-motile, rod-shaped bacteria closely related to Escherichia coli and Salmonella. The causative agent of human shigellosis, Shigella causes disease in primates, but not in other mammals. It is only naturally found in humans and apes. During... spp |
2-30% |
| Salmonella Salmonella Salmonella is a genus of rod-shaped, Gram-negative, non-spore-forming, predominantly motile enterobacteria with diameters around 0.7 to 1.5 µm, lengths from 2 to 5 µm, and flagella which grade in all directions . They are chemoorganotrophs, obtaining their energy from oxidation and reduction... spp |
0-33% |
| Campylobacter jejuni Campylobacter jejuni Campylobacter jejuni is a species of curved, helical-shaped, non-spore forming, Gram-negative, microaerophilic bacteria commonly found in animal feces. It is one of the most common causes of human gastroenteritis in the world. Food poisoning caused by Campylobacter species can be severely... |
3-17% |
| Vibrio parahemolyticus | 0-31% |
| Aeromonas hydrophila Aeromonas hydrophila Aeromonas hydrophila is a heterotrophic, Gram-negative, rod shaped bacterium, mainly found in areas with a warm climate. This bacterium can also be found in fresh, salt, marine, estuarine, chlorinated, and un-chlorinated water. Aeromonas hydrophila can survive in aerobic and anaerobic... |
0-30% |
| Giardia lamblia Giardia lamblia Giardia lamblia is a flagellated protozoan parasite that colonizes and reproduces in the small intestine, causing giardiasis. The giardia parasite attaches to the epithelium by a ventral adhesive disc, and reproduces via binary fission... |
0 to less than 20% |
| Entamoeba histolytica Entamoeba histolytica Entamoeba histolytica is an anaerobic parasitic protozoan, part of the genus Entamoeba. Predominantly infecting humans and other primates, E. histolytica is estimated to infect about 50 million people worldwide... |
0-5% |
| Cryptosporidium Cryptosporidium Cryptosporidium is a protozoan that can cause gastro-intestinal illness with diarrhea in humans.Cryptosporidium is the organism most commonly isolated in HIV positive patients presenting with diarrhea... sp |
0 to less than 20% |
| Rotavirus Rotavirus Rotavirus is the most common cause of severe diarrhoea among infants and young children, and is one of several viruses that cause infections often called stomach flu, despite having no relation to influenza. It is a genus of double-stranded RNA virus in the family Reoviridae. By the age of five,... |
0-36% |
| Norwalk virus | 0-10% |
Infectious agent
Pathogen
A pathogen gignomai "I give birth to") or infectious agent — colloquially, a germ — is a microbe or microorganism such as a virus, bacterium, prion, or fungus that causes disease in its animal or plant host...
s are the primary cause of travelers' diarrhea. Bacterial enteropathogens
Enterobacteriaceae
The Enterobacteriaceae is a large family of bacteria that includes many of the more familiar pathogens, such as Salmonella, Escherichia coli, Yersinia pestis, Klebsiella and Shigella. This family is the only representative in the order Enterobacteriales of the class Gammaproteobacteria in the...
cause approximately 80% of cases. Viruses and protozoans account for most of the rest.
The most common causative agent isolated in countries surveyed has been enterotoxigenic Escherichia coli
Enterotoxigenic Escherichia coli
Enterotoxigenic Escherichia coli is a type of Escherichia coli and the leading bacterial cause of diarrhea in the developing world, as well as the most common cause of traveler's diarrhea. Each year, approximately 210 million cases and 380,000 deaths occur, mostly in children, from ETEC...
(ETEC). Enteroaggregative E. coli
Escherichia coli
Escherichia coli is a Gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms . Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in humans, and are occasionally responsible for product recalls...
is increasingly recognized and many studies do not look for this important bacterium. Shigella
Shigella
Shigella is a genus of Gram-negative, nonspore forming, non-motile, rod-shaped bacteria closely related to Escherichia coli and Salmonella. The causative agent of human shigellosis, Shigella causes disease in primates, but not in other mammals. It is only naturally found in humans and apes. During...
spp. and Salmonella
Salmonella
Salmonella is a genus of rod-shaped, Gram-negative, non-spore-forming, predominantly motile enterobacteria with diameters around 0.7 to 1.5 µm, lengths from 2 to 5 µm, and flagella which grade in all directions . They are chemoorganotrophs, obtaining their energy from oxidation and reduction...
spp. are other common bacterial pathogens. Campylobacter
Campylobacter
Campylobacter is a genus of bacteria that are Gram-negative, spiral, and microaerophilic. Motile, with either unipolar or bipolar flagella, the organisms have a characteristic spiral/corkscrew appearance and are oxidase-positive. Campylobacter jejuni is now recognized as one of the main causes...
, Yersinia
Yersinia
Yersinia is a genus of bacteria in the family Enterobacteriaceae. Yersinia are Gram-negative rod shaped bacteria, a few micrometers long and fractions of a micrometer in diameter, and are facultative anaerobes. Some members of Yersinia are pathogenic in humans; in particular, Y. pestis is the...
, Aeromonas
Aeromonas
Aeromonas is a gram-negative, facultative anaerobic rod that morphologically resembles members of the family Enterobacteriaceae. Fourteen species of Aeromonas have been described, most of which have been associated with human diseases. The most important pathogens are A. hydrophila, A. caviae, and...
, and Plesiomonas spp. are less frequently found. Some bacteria release toxin
Toxin
A toxin is a poisonous substance produced within living cells or organisms; man-made substances created by artificial processes are thus excluded...
s which bind to the intestinal wall and cause diarrhea; others damage the intestines themselves by their direct presence.
While viruses are associated with less than 20% of adult cases of traveler's diarrhea, they may be responsible for nearly 70% of cases in infants and children. Diarrhea due to viral agents is unaffected by antibiotic therapy, but is usually self-limited. Protozoans such as Giardia lamblia
Giardia lamblia
Giardia lamblia is a flagellated protozoan parasite that colonizes and reproduces in the small intestine, causing giardiasis. The giardia parasite attaches to the epithelium by a ventral adhesive disc, and reproduces via binary fission...
and Cryptosporidium
Cryptosporidium
Cryptosporidium is a protozoan that can cause gastro-intestinal illness with diarrhea in humans.Cryptosporidium is the organism most commonly isolated in HIV positive patients presenting with diarrhea...
can also cause diarrhea.
Pathogens implicated in travelers' diarrhea appear in the table at right.
A sub-type of traveler's diarrhea afflicting hikers and campers, sometimes known as wilderness diarrhea, may have a somewhat different frequency distribution of pathogens.
Risk factors
The primary source of infection is ingestion of fecally-contaminated food or water. Attack rates are similar for men and women.The most important determinant of risk is the traveler's destination. High risk destinations include developing countries
Developing country
A developing country, also known as a less-developed country, is a nation with a low level of material well-being. Since no single definition of the term developing country is recognized internationally, the levels of development may vary widely within so-called developing countries...
in Latin America, Africa, the Middle East, and Asia. Among backpackers, additional risk factors include drinking untreated surface water and failure to maintain personal hygiene practices and clean cookware. Campsites often have very primitive (if any) sanitation facilities, making them potentially as dangerous as any developing country.
Although traveler's diarrhea usually resolves within three to five days (mean duration: 3.6 days), in about 20% of cases the illness is severe enough to require bedrest, and in 10% the illness duration exceeds one week. For those prone to serious infections, such as bacillary dysentery
Bacillary dysentery
Bacillary dysentery is a type of dysentery, and is a severe form of shigellosis.Bacillary dysentery is associated with species of bacteria from the Enterobacteriaceae family. The term is usually restricted to Shigella infections....
, amoebic dysentery
Amoebic dysentery
Amoebic dysentery is a type of dysentery caused primarily by the amoeba Entamoeba histolytica. Amoebic dysentery is transmitted through contaminated food and water. Amoebae spread by forming infective cysts which can be found in stools, and spread if whoever touches them does not sanitize their...
, and cholera
Cholera
Cholera is an infection of the small intestine that is caused by the bacterium Vibrio cholerae. The main symptoms are profuse watery diarrhea and vomiting. Transmission occurs primarily by drinking or eating water or food that has been contaminated by the diarrhea of an infected person or the feces...
, TD can occasionally be life-threatening. Others at higher-than-average risk include young adults, immunosuppressed
Immunosuppression
Immunosuppression involves an act that reduces the activation or efficacy of the immune system. Some portions of the immune system itself have immuno-suppressive effects on other parts of the immune system, and immunosuppression may occur as an adverse reaction to treatment of other...
persons, persons with inflammatory bowel disease
Inflammatory bowel disease
In medicine, inflammatory bowel disease is a group of inflammatory conditions of the colon and small intestine. The major types of IBD are Crohn's disease and ulcerative colitis.-Classification:...
or diabetes, and those taking H2 blockers or antacids.
Immunity
Travelers often get diarrhea from eating and drinking products that have no such effect on local residents. This is due to immunityImmunity (medical)
Immunity is a biological term that describes a state of having sufficient biological defenses to avoid infection, disease, or other unwanted biological invasion. Immunity involves both specific and non-specific components. The non-specific components act either as barriers or as eliminators of wide...
that develops after repeated exposure to pathogens. It is not fully clear how much exposure is needed, and to what extent the immune system can become tolerant to pathogens, but a study among expatriates in Nepal suggests that it can take seven years to develop immunity—presumably in adults who avoid deliberate pathogen exposure.
Conversely, immunity that American students acquired while living in Mexico appeared to disappear within as little as 8 weeks of cessation of exposure.
Prevention
The best means of prevention is to avoid any questionable foods or beverages. Traveler's diarrhea is fundamentally a sanitation failure, leading to bacterial contamination of drinking water and food. It is best prevented through proper water quality management systems, as found in responsible hotels and resorts. In the absence of that, the next best option for travelers is to take individual precautions:- Drink safe beverages, which include bottled water, bottled carbonated beverages, hot tea or coffee, and water boiled or appropriately treated by the traveler. Caution should be exercised with hot beverages, which may be only heated, not boiled.
- Maintain good hygiene and only use safe water for drinking and tooth brushing.
- Avoid ice, which may not have been made with bottled water.
- In restaurants, insist that bottled water be unsealed in your presence. Reports of locals filling empty bottles with untreated tap water and reselling them as purified water have come out of several countries. When in doubt, a bottled carbonated beverage is the safest choice, since it is almost impossible to "fake" carbonation when refilling a used bottle.
- Avoid eating raw fruits and vegetables unless the traveler peels them personally.
- Avoid green salads, because it is unlikely that the lettuce will have been washed with bottled water.
If handled properly, well-cooked and packaged foods are usually safe. Eating raw or undercooked meat and seafood should be avoided. Unpasteurized
Pasteurization
Pasteurization is a process of heating a food, usually liquid, to a specific temperature for a definite length of time, and then cooling it immediately. This process slows microbial growth in food...
milk, dairy products, mayonnaise and pastry icing are associated with increased risk for TD, as are foods or drinking beverages purchased from street vendors or other establishments where unhygienic conditions may be present.
Active intervention involves boiling water for three to five minutes (depending on elevation), filtering water with appropriate filters or using chlorine bleach (2 drops per litre) or tincture of iodine (5 drops per litre) in the water. The wide availability of safe bottled water makes these interventions unnecessary for all but the most remote destinations.
An ultraviolet (UV) water purification device is available commercially that allows treatment of small amounts of water at room temperature. The UV light bonds DNA thymine
Thymine
Thymine is one of the four nucleobases in the nucleic acid of DNA that are represented by the letters G–C–A–T. The others are adenine, guanine, and cytosine. Thymine is also known as 5-methyluracil, a pyrimidine nucleobase. As the name suggests, thymine may be derived by methylation of uracil at...
rings, preventing the survival or replication of any infectious organisms in the water. UV light also kills viruses, which are not typically removed by filtration (although filtration is recommended prior to treatment if the water is visibly clouded). Other claimed advantages include no taste alteration, elimination of need for boiling, and decreased long-term cost compared with bottled water.
Other preventive measures include over-the-counter anti-diarrhea products and in certain situations, prophylactic medications and supplements. Studies show a decrease in the incidence of TD with use of bismuth subsalicylate
Bismuth subsalicylate
Bismuth subsalicylate, with a nominal chemical formula of C7H5BiO4, It is a colloidal substance obtained by hydrolysis of bismuth salicylate . The actual structure is unknown and the formulation is only approximate. Recent evidence indicates that it is composed of a bismuth oxide core structure...
and antimicrobial chemoprophylaxis
Chemoprophylaxis
Chemoprophylaxis refers to the administration of a medication for the purpose of preventing disease or infection. Antibiotics, for example, may be administered to patients with disorders of immune system function to prevent bacterial infections...
.
Bismuth subsalicylate (two tablets or two ounces four times daily) will reduce the likelihood of travelers' diarrhea, but few travelers adhere to a four-times-per-day regimen because it is inconvenient. Side effects may include black tongue, black stools, nausea, constipation, and ringing in the ears (tinnitus
Tinnitus
Tinnitus |ringing]]") is the perception of sound within the human ear in the absence of corresponding external sound.Tinnitus is not a disease, but a symptom that can result from a wide range of underlying causes: abnormally loud sounds in the ear canal for even the briefest period , ear...
). Bismuth subsalicylate should not be taken by those with aspirin allergy, kidney disease, or gout, nor concurrently with certain antibiotics, and should not be taken for more than three weeks.
Though effective, antibiotics are not recommended in most situations to prevent diarrhea before it occurs, because of the risk of adverse reactions to the antibiotics, and because intake of prophylactic antibiotics may decrease effectiveness of such drugs should a serious infection occur. Antibiotics can also cause vaginal yeast infections (which many women consider a worse problem than the diarrhea). Also, antibiotics can cause a disease called pseudomembranous colitis
Pseudomembranous colitis
Pseudomembranous colitis, a cause of antibiotic-associated diarrhea , is an infection of the colon. It is often, but not always, caused by the bacterium Clostridium difficile. Because of this, the informal name C. difficile colitis is also commonly used. The illness is characterized by...
which results in severe, unrelenting diarrhea.
However, prophylaxis may be warranted in special situations where benefits outweigh the above risks, such as immunocompromised travelers, chronic intestinal disorders, prior history of repeated disabling bouts of traveler's diarrhea, or scenarios in which onset of diarrhea might prove particularly troublesome. Options for prophylactic treatment include the quinolone antibiotics (norfloxacin
Norfloxacin
Norfloxacin is a synthetic chemotherapeutic antibacterial agent occasionally used to treat common as well as complicated urinary tract infections. It is sold under various brand names with the most common being Noroxin. In form of ophthalmic solutions it is known as Chibroxin...
, ciprofloxacin
Ciprofloxacin
Ciprofloxacin is a synthetic chemotherapeutic antibiotic of the fluoroquinolone drug class.It is a second-generation fluoroquinolone antibacterial. It kills bacteria by interfering with the enzymes that cause DNA to rewind after being copied, which stops synthesis of DNA and of...
, ofloxacin
Ofloxacin
Ofloxacin is a synthetic chemotherapeutic antibiotic of the fluoroquinolone drug class considered to be a second-generation fluoroquinolone. The original brand, Floxin, has been discontinued by the manufacturer in the United States on 18 June 2009, though generic equivalents continue to be...
, among others), and trimethoprim/sulfamethoxazole. Quinolone antibiotics may bind to metallic cations such as bismuth, and should not be taken concurrently with bismuth subsalicylate. Trimethoprim/sulfamethoxazole should not be taken by anyone with a history of sulfa allergy.
A few pathogen-specific vaccine
Vaccine
A vaccine is a biological preparation that improves immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism, and is often made from weakened or killed forms of the microbe or its toxins...
s have become available, and others are under development. Dukoral, an oral vaccine against Vibrio cholerae
Vibrio cholerae
Vibrio cholerae is a Gram-negative, comma-shaped bacterium. Some strains of V. cholerae cause the disease cholera. V. cholerae is facultatively anaerobic and has a flagella at one cell pole. V...
, has demonstrated up to 43% protective efficacy against TD when one dose is given a few weeks before travel and a second a week before travel, although it is not officially approved for that indication in most countries. Several vaccine candidates targeting enterotoxigenic E. coli and Shigella are in various stages of development.
A patch-delivered travelers’ diarrhea vaccine is under development by Iomai (which was acquired by Intercell
Intercell
Intercell AG is a biotechnology company based in Vienna which focuses on the development of modern prophylactic and therapeutic vaccines against infectious diseases...
in 2008). Results of a phase II clinical trial, published in 2008 in The Lancet, indicate significant protection from clinically significant diarrhea compared with placebo. The vaccine remains experimental, at the phase III clinical trial level, and is not yet licensed in any country.
In 2009 a research group at the University of Guelph
University of Guelph
The University of Guelph, also known as U of G, is a comprehensive public research university in Guelph, Ontario, Canada. It was established in 1964 after the amalgamation of Ontario Agricultural College, the Macdonald Institute, and the Ontario Veterinary College...
announced that it was working on a TD vaccine targeting Campylobacter jejuni. To date, no human clinical trials have been reported.
Travelan
Travelan
Travelan is a commercially available medicinal product used to prevent traveller's diarrhoea. Travelan is manufactured and sold in Australia, and is only available in the United States by purchasing online.-Mechanism of action:...
is a proprietary mix of antibodies against common strains of E.Coli involved in travellers diarrhea. The manufacturer claims that the antibodies inhibit ETEC attachment to the intestinal wall, and avoid killing beneficial flora because of their specificity to ETEC strains. When taken orally before every meal, the manufacturer claims prevention of TD "in up to 93% of volunteers", but no impartial placebo-controlled studies have been published. In 2010 the product underwent an FDA recall after it "...failed to meet stability specifications when assayed at approximately 3 months after being manufactured."
Two probiotics (Saccharomyces boulardii
Saccharomyces boulardii
Saccharomyces boulardii is a tropical strain of yeast first isolated from lychee and mangosteen fruit in 1923 by French scientist Henri Boulard. It is related to, but distinct from, Saccharomyces cerevisiae in several taxonomic, metabolic, and genetic properties. S...
and a mixture of Lactobacillus acidophilus
Lactobacillus acidophilus
Lactobacillus acidophilus is a species in the genus Lactobacillus. L. acidophilus is a homofermentative species, fermenting sugars into lactic acid, which grows readily at rather low pH values and has an optimum growth temperature of 37 °C . L...
and Bifidobacterium bifidum) have been studied as a treatment for TD. In a meta-analysis
Meta-analysis
In statistics, a meta-analysis combines the results of several studies that address a set of related research hypotheses. In its simplest form, this is normally by identification of a common measure of effect size, for which a weighted average might be the output of a meta-analyses. Here the...
by McFarland (2005), no serious adverse reactions were reported in 12 trials. These probiotics may offer a safe and effective method to prevent TD, but due to strain stability and survivability issues, they may not always be an appropriate choice.
Prebiotics, as an alternative, are more stable than probiotics during passage through the upper gastrointestinal tract and are able to induce antimicrobial effects principally through their selective stimulation of our own beneficial gut bacteria. However, prebiotics act mainly in the large intestine, while the infective organisms causing TD act in the small intestine. Therefore, current prebiotics (such as fructooligosaccharide
Fructooligosaccharide
Fructooligosaccharides also sometimes called oligofructose or oligofructan, are oligosaccharide fructans, used as an alternative sweetener. FOS exhibits sweetness levels between 30 and 50 percent of sugar in commercially-prepared syrups...
) have very limited application as preventative agents. Second generation prebiotic galactooligosaccharides
Galactooligosaccharides
Galacto-oligosaccharides , also known as oligogalactosyllactose, oligogalactose, oligolactose or transgalactooligosaccharides , belong, because of their indigestible nature, to the group of prebiotics. Prebiotics are defined as non-digestible food ingredients that beneficially affect the host by...
, such as B-GOS (Bimuno), have additional properties such as positive effect on immunity and direct interaction with the host gut epithelium, preventing the attachment and invasion of gastrointestinal pathogens. B-GOS was shown to result in significant reduction in the incidence and duration of TD in a study with human volunteers travelling to countries with medium to high risk of developing TD.
Treatment
Most cases of TD are mild and resolve in a few days without treatment with antibiotics or antimotility drugs. Severe or protracted cases, however, may result in significant fluid loss and dangerous electrolytic imbalanceElectrolyte disturbance
Electrolytes play a vital role in maintaining homeostasis within the body. They help to regulate myocardial and neurological function, fluid balance, oxygen delivery, acid-base balance and much more. Electrolyte imbalances can develop by the following mechanisms: excessive ingestion; diminished...
. Adequate fluid intake (oral rehydration therapy
Oral rehydration therapy
Oral rehydration therapy is a simple treatment for dehydration associated with diarrhoea, particularly gastroenteritis or gastroenteropathy, such as that caused by cholera or rotavirus. ORT consists of a solution of salts and sugars which is taken by mouth...
) is essential to replace lost fluids and electrolytes. Clear, disinfected water or other liquids are routinely recommended for adults. Water that is purified is best, along with oral rehydration salts to replenish lost electrolytes. Carbonated water (soda), which has been left out so that the carbonation fizz is gone, is useful if nothing else is available. In severe or protracted cases, the oversight of a medical professional is advised.
Antibiotics
If diarrhea becomes severe (typically defined as three or more loose stools in a 24-hour period) — or if diarrhea is bloody, or fever occurs with shaking chills, or abdominal pain becomes marked, or diarrhea persists for more than 72 hours — medical treatment should be sought. Such patients may benefit from antimicrobial therapy. Antibiotics are typically given for three to five days, but single doses of azithromycinAzithromycin
Azithromycin is an azalide, a subclass of macrolide antibiotics. Azithromycin is one of the world's best-selling antibiotics...
or levofloxacin have been used. If diarrhea persists despite therapy, travelers should be evaluated for possible viral or parasitic infections, bacterial or amoebic dysentery, Giardia, helminths, or cholera.
Antimotility agents
Antimotility drugs such as loperamideLoperamide
Loperamide , a synthetic piperidine derivative, is an opioid drug used against diarrhea resulting from gastroenteritis or inflammatory bowel disease. In most countries it is available generically and under brand names such as Lopex, Imodium, Dimor, Fortasec, and Pepto Diarrhea Control...
and diphenoxylate
Diphenoxylate
Diphenoxylate is an opioid agonist used for the treatment of diarrhea that acts by slowing intestinal contractions and peristalsis allowing the body to consolidate intestinal contents and prolong transit time, thus allowing the intestines to draw moisture out of them at a normal or higher rate and...
reduce the symptoms of diarrhea by slowing transit time in the gut. They should be taken as necessary to slow the frequency of stools, but not enough to stop bowel movements completely, which delays expulsion of the causative organisms from the intestines. Adverse reactions may include nausea, vomiting, abdominal pain, hives or rash, and loss of appetite. Antimotility agents should not, as a rule, be given to children under age two.
Society and culture
There are a number of colloquialismColloquialism
A colloquialism is a word or phrase that is common in everyday, unconstrained conversation rather than in formal speech, academic writing, or paralinguistics. Dictionaries often display colloquial words and phrases with the abbreviation colloq. as an identifier...
s for travelers' diarrhea contracted in various localities, such as "Montezuma's revenge", "turistas", or "Aztec two step" in Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
; and "Pharaoh's Revenge," "mummy's tummy," or "Cairo two-step" in Egypt
Egypt
Egypt , officially the Arab Republic of Egypt, Arabic: , is a country mainly in North Africa, with the Sinai Peninsula forming a land bridge in Southwest Asia. Egypt is thus a transcontinental country, and a major power in Africa, the Mediterranean Basin, the Middle East and the Muslim world...
. Many other colorful synonyms exist in other regions of the world, some of which have found their way into the arts and literature. For example, Aamir Khan
Aamir Khan
Aamir Hussain Khan is an Indian film actor, director and producer who has established himself as one of the leading actors of Hindi cinema....
titled his 2011 Hindi film Delhi Belly, after the popular Indian colloquialism.
Montezuma's revenge
Montezuma's revenge (var. Moctezuma's revenge) is the colloquial term for any cases of traveler's diarrhea contracted by tourists visiting MexicoMexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
. The name refers to Moctezuma II
Moctezuma II
Moctezuma , also known by a number of variant spellings including Montezuma, Moteuczoma, Motecuhzoma and referred to in full by early Nahuatl texts as Motecuhzoma Xocoyotzin, was the ninth tlatoani or ruler of Tenochtitlan, reigning from 1502 to 1520...
(1466–1520), the Tlatoani
Tlatoani
Tlatoani is the Nahuatl term for the ruler of an altepetl, a pre-Hispanic state. The word literally means "speaker", but may be translated into English as "king". A is a female ruler, or queen regnant....
(ruler) of the Aztec
Aztec
The Aztec people were certain ethnic groups of central Mexico, particularly those groups who spoke the Nahuatl language and who dominated large parts of Mesoamerica in the 14th, 15th and 16th centuries, a period referred to as the late post-classic period in Mesoamerican chronology.Aztec is the...
civilization who was defeated by Hernán Cortés
Hernán Cortés
Hernán Cortés de Monroy y Pizarro, 1st Marquis of the Valley of Oaxaca was a Spanish Conquistador who led an expedition that caused the fall of the Aztec Empire and brought large portions of mainland Mexico under the rule of the King of Castile in the early 16th century...
, the Spanish conquistador.
Wilderness diarrhea
Wilderness diarrhea (WD), also called wilderness-acquired diarrhea (WAD) or backcountry diarrhea, is the name preferred by some backpackers, hikers, campers and other outdoor recreationalists for traveler's diarrhea that appears in wilderness or "backcountry" situations, either at home or abroad. It is due to the same agents as all other traveler's diarrhea, which are usually bacterial and viral in short expeditions, but may be giardiasisGiardiasis
Giardiasis or beaver fever in humans is a diarrheal infection of the small intestine by a single-celled organism Giardia lamblia. Giardiasis occurs worldwide with a prevalence of 20–30% in developing countries. In the U.S., 20,000 cases are reported to the CDC annually, but the true annual...
in longer expeditions. It is often due to the absence of treated water and poor hygiene. Since wilderness campsites seldom provide access to sanitation facilities, the infection risk is similar to that of any developing country. Some people reserve the name backpacker's diarrhea as a synonym for giardiasis.