Traveler's diarrhea

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Traveler's diarrhea (in American English) or traveller's diarrhœa (in British English), abbreviated to TD, is the most common illness affecting travelers. Traveler's diarrhea is defined as three or more unformed stools in 24 hours, commonly accompanied by abdominal cramps, nausea, and bloating.

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[edit] Incidence

Each year 20%–50% of international travelers, an estimated 10 million people, develop diarrhea.[1] 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. TD is also known to mountaineers, as it can occur in camps due to poor sanitary conditions.

[edit] Causative organisms

Among the microorganisms responsible, bacteria represent approximately 61%. Enterotoxigenic Escherichia coli, enteroaggregative E. coli, and Shigella spp. are the most common bacteria involved. Incidents in which other bacteria, such as Salmonella, Campylobacter, Yersinia, Aeromonas, and Plesiomonas spp., have caused diarrhea are isolated and occur less often. Also protozoan parasites such as Giardia lamblia and Cryptosporidium, may cause diarrhea.

[edit] Risk factors

The most important determinant of risk is the traveler's destination. The primary source of infection is ingestion of fecally contaminated food or water. High-risk destinations are the developing countries of Latin America, Africa, the Middle East, and Asia. Some first world countries are also deemed risky however.[2] A worldwide rating of drinking water safety is kept at Safe Water for International Travelers website.[3]

[edit] Particular risk

People at particular high-risk include young adults, immunosuppressed persons, persons with inflammatory-bowel disease or diabetes, and persons taking H-2 blockers or antacids. Attack rates are similar for men and women.

Although traveler's diarrhea usually resolves within three to five days (mean duration: 3.6 days), in about 20 percent of persons the illness is severe enough to cause bed confinement and in 10 percent of cases the illness lasts more than one week.[citation needed]

For those who get serious infections, TD can occasionally be life-threatening. The serious infections include bacillary dysentery, amoebic dysentery, and cholera.

[edit] Common symptom

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. Most TD cases begin abruptly. The illness usually results in increased frequency, volume, and weight of stool. Altered stool consistency also is common. 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 usually the appetite is low or non-existent.

It is much more serious if there is blood or mucus in the diarrhea, belly pain, or high fever. Dehydration is possible. With serious cases of cholera, there is a rapid onset of symptoms, which include weakness, malaise (feeling rotten), and torrents of watery diarrhea with flecks of mucus (called "rice water" stools). Dehydration is a serious consequence, with death occurring in as quickly as 24 hours with cholera.

[edit] Causes of travelers' diarrhea

There are many causes of diarrhea and it is important to recognize which ones are serious and which are not. Infectious agents are the primary cause of TD. Bacterial enteropathogens cause approximately 80% of TD cases.[citation needed] Pathogens implicated in travellers' diarrhea are: [4]

E. coli, enterotoxigenic 20-75%
E. coli, enteroaggregative 0-20%
E. coli, enteroinvasive 0-6%
Shigella spp 2-30%
Salmonella spp  0-33%
Campylobacter jejuni 3-17%
Vibrio parahemolyticus 0-31%
Aeromonas hydrophila 0-30%
Giardia lamblia 0 to less than 20%
Entameba histolytica  0-5%
Cryptosporidium sp 0 to less than 20%
Rotavirus 0-36%
Norwalk virus 0-10%

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. Some bacteria release toxins which bind to the intestines and cause diarrhea; others damage the intestines themselves by their direct presence. In infants and children, it is estimated that nearly 70% of diarrhea is due to viruses; for adult travelers, this drops to around 30%. Diarrhea caused by viral agents is usually self-limited.

[edit] Treatment

TD usually is a self-limited disorder and often resolves without specific treatment; however, oral rehydration therapy is often beneficial to replace lost fluids and electrolytes. Clear 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 quite useful.[citation needed]

Travelers who develop three or more loose stools in a 24-hour period — especially if associated with nausea, vomiting, abdominal cramps, fever, or blood in stools — should be treated by a doctor and may benefit from antimicrobial therapy. Antibiotics usually are given for 3–5 days, but single dose azithromycin or levofloxacin have been used.[5] If diarrhea persists despite therapy, travelers should be evaluated and treated for possible parasitic infection. There are different medications needed for bacterial dysentery, for amoebic dysentery, for giardia and for worms. There is no medication for Cryptosporidium, which can devastate people with AIDS. There can be 100% recovery from cholera when properly treated, which usually only means rehydration, usually through an intravenous line.

[edit] Treating with antimotility agents

Antimotility agents (loperamide, diphenoxylate, and paregoric) primarily reduce diarrhea by slowing transit time in the gut, and, thus, allows more time for absorption. Some persons[who?] believe diarrhea is the body's defense mechanism to minimize contact time between gut pathogens and intestinal mucosa. In several studies[who?], antimotility agents have been useful in treating travelers' diarrhea by decreasing the duration of diarrhea. However, these agents should never be used by persons with fever or bloody diarrhea, because they can increase the severity of disease by delaying clearance of causative organisms. Because antimotility agents are now available over the counter, their injudicious use is of concern. Adverse complications (toxic megacolon, sepsis, and disseminated intravascular coagulation) have been reported[who?] as a result of using these medications to treat diarrhea.

[edit] Prophylaxis

It is not recommend to take antimicrobial drugs to prevent TD, because they kill off beneficial bacteria and create resistant breeds of pathogenic (disease-causing) bacteria. Among the primary measures to prevent gastrointestinal illness are keeping good hygiene, getting specific vaccines and prophylactic medications. Studies show a decrease in the incidence of TD with use of bismuth subsalicylate and with use of antimicrobial chemoprophylaxis.

Dukoral has been shown to prevent TD and cholera - one dose a few weeks before travel, and another about a week before travel.

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 the educated traveler is to take precautions to prevent the disease:

  • Maintain good hygiene and make sure that you drink safe water, even for teeth brushing.
  • Use only safe bottled water and avoid ice. Reports of locals filling bottles with tap water, then sealing them and then selling the bottled water as purified water have come out of several countries[citation needed].
  • Drink safe beverages include bottled carbonated beverages, hot tea or coffee, beer, wine, and water boiled or appropriately treated by yourself.
  • 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 usually unnecessary for all but the most remote destinations.
  • Avoid eating raw fruits and vegetables unless the traveler peels them.
  • Recently an Ultra Violet Water Purification device has entered the market that allows people to quickly and conveniently treat small amounts of water, even in restaurant settings. The method of action is UV light bonding Thymine rungs of the DNA molecule, destroying the organisms ability to live or replicate. The major advantage (besides convenience) is that Ultraviolet light also kills viruses when filtration does not. Many travelers are opting for this method because it adds no taste to the water, allows the drinking of cold water, and is extremely economical versus the cost of buying bottled water.

If handled properly, well-cooked and packaged foods are usually safe. Avoid eating raw or undercooked meat and seafood. 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 are present.

Several probiotics (Saccharomyces boulardii and a mixture of Lactobacillus acidophilus and Bifidobacterium bifidum) have significant efficacy. In a meta-analysis by McFarland (2005), no serious adverse reactions were reported in the 12 trials. Probiotics may offer a safe and effective method to prevent TD.[6]

[edit] Colloquialisms for TD

There are a number of colloquialisms for travelers' diarrhea contracted in various localities, such as "Montezuma's Revenge" for travelers' diarrhea contracted in Mexico, or "Delhi Belly" in India. A more recent local term in Pattaya, Thailand, is known as having a "Thai-dal Wave".

[edit] 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 Mexico. The name humorously refers to Montezuma II (1466-1520), the Tlatoani (ruler) of the Aztec civilization who was defeated by Hernándo Cortés the Spanish conquistador.

It is estimated that 40% of foreign traveler vacations in Mexico are disrupted by infection.[7] Most cases are mild and resolve in a few days with no treatment. Severe or extended cases, however, may result in extensive fluid loss and/or dangerous electrolytic imbalance which pose a severe medical risk and may prove fatal if mismanaged. The oversight of a medical professional is advised.

Not all water supplies in Mexico are contaminated and many hotels have water purification systems that eliminate risk. Certain resort destinations also have large-scale water purification systems which provide safe water city-wide. Roadside and popular food stalls specifically should be avoided.

[edit] See also

[edit] References

  1. ^ Travelers' Diarrhea.
  2. ^ European Commission (March 22, 2007). "Portugal: Commission continues legal action over environmental and human health infringements". Press release. Retrieved on 2008-02-25.
  3. ^ Safe Water for International Travelers. safewateronline.com.
  4. ^ Travelers' diarrhea. safewateronline.com.
  5. ^ Sanders JW, Frenck RW, Putnam SD, et al. (2007). "Azithromycin and loperamide are comparable to levofloxacin and loperamide for the treatment of traveler's diarrhea in United States military personnel in Turkey". Clin Infect Dis 45: 294–301. doi:10.1086/519264. 
  6. ^ McFarland, Lynn. "Meta-analysis of probiotics for the prevention of traveller’s diarrhoea". Travel Medicine and Infectious Disease 5 (2): 97-105. 
  7. ^ Dupont HL, Haynes GA, Pickering LK, Tjoa W, Sullivan P, Olarte J (1977). "Diarrhea of travelers to Mexico. Relative susceptibility of United States and Latin American students attending a Mexican University". Am. J. Epidemiol. 105 (1): 37–41. PMID 831463. 

This article contains material from the CDC (Center for Disease Control) website which, as a US government publication, is in the public domain.