Travelers' Diarrhea

Traveler’s diarrhea is a clinical syndrome of diarrhea, abdominal cramps, sometimes nausea, and vomiting and low grade fever caused by a variety of pathogens including bacteria, viruses, parasites and even pre-formed toxins. Therefore this syndrome does not indicate a specific pathogen, rather the way you acquired the illness; by travel, thus traveler’s diarrhea.

Travelers’ diarrhea is the most common illness in individuals traveling from developed countries to developing countries; being seen in nearly 40 – 60% of travelers.

 Even though it infrequently leads to serious complications and most illness can resolve by itself, even mild to moderate illness can ruin one’s enjoyment of the trip, wreck schedules, frustrate leisure or business activities and make one terrified about finding a toilet in places where restrooms are not readily available or worse the sight of which can make you even sicker.

Dehydration resulting from fluid losses and inability to keep fluids in due to vomiting poses the biggest health problem to travelers.

What are the pathogens that cause traveler’s diarrhea?

Bacterial pathogens are responsible for nearly 85-90% of travelers’ diarrhea with Escherichia coli (enterotoxigenic & enteroaggregative) responsible for the majority of cases (60%). Parasites, Viruses and pre-formed Toxins are the other pathogens involved in causing travelers’ diarrhea.

Bacteria - responsible for 85-90 % of cases

Enterotoxigenic Escherichia Coli & Enteroaggregative E. Coli (60%), Campylobacter jejuni, Salmonella species, Shigella species and Vibrio species. Other bacteria that are rarely seen include Aeromonas hydrophila, Plesiomonas shigelloides, Yersinia enterocolitica and Enterotoxigenic Bacteriodes fragilis.

Parasites – responsible for 10 % of cases

 Giardia intestinalis, Cryptosporidium parvum, Cyclospora cayetanensis, Entamoeba histolytica and Dientamoeba fragilis.

Viruses – responsible for 5% of cases

Rotovirus and Norovirus cause nearly all the cases. They are more commonly associated with cruise ships.

Toxins – responsible for 2-4 % of cases

Pre-formed Staphylococcus aureus, Clostridium perfringens and Bacillus cereus toxins.

Where does it occur?

I t occurs worldwide, but risks vary according to regions as described below.

High risk: Asia, Most of Africa, Mexico, Central and Most of South America.

Moderate risk: Eastern Europe, Russia, South Africa, Argentina, Chile.

Low risk: United States, Canada, Western Europe, Australia, New Zealand, Singapore, Japan.

How is it transmitted?

It is transmitted primarily through fecally contaminated food and water. It is also transmitted by ingesting fecal material of an infected individual through soiled hands.

Is it contagious from person to person?

Depending on the bacteria, parasite or virus responsible it can be contagious from person to person by ingesting fecal material of an infected individual through soiled hands or surfaces.

What is the risk for travelers?

The risk for travelers to developing nations is quite high, occurring in 40-60% of travelers.

 Individuals who take antacids, anti ulcer medications (Tagamet, Zantac, Protonix, Nexium etc) or have had intestinal surgery for ulcers may have an increased risk of disease since stomach acid is not available to kill bacteria.

Individuals who have inflammatory bowel disease like Ulcerative colitis and Crohn’s are at risk for severe disease and exacerbation of colitis.

How soon after exposure will one develop symptoms?

Symptoms can develop from a few hours, days to a week after exposure depending on the agent responsible.

Bacteria: symptoms occurs from 1- 3 days after exposure

Viruses: symptoms occur 1-2 days after exposure

Parasites: symptoms occur 1-2 weeks after exposure

Toxins: symptoms are seen typically within 6 hours to 12 hours after exposure

What are the signs and symptoms?

Symptoms include a feeling of malaise, bloating, abdominal cramps, queasiness, nausea, low grade fever followed by sudden onset of watery loose to semi formed stools. Typically one does not see bloody diarrhea or high fevers.

Toxin and viral mediated illnesses are frequently associated more with episodes of vomiting with or without diarrhea.

Parasitic diseases usually take a bit longer to appear and symptoms may last longer without relief. Belching, bloating and queasiness are commonly seen with Giardia infections, while large volume watery diarrhea is seen more commonly with Cryptosporidium and Cyclospora infections.

 Infections with Campylobacter and Shigella can progress to involve high fever, painful rectal spasm, urge to suddenly use the toilet and bloody diarrhea.

Are there any lab tests to diagnose the illness?

Bacteria, Viruses, Parasites and Toxin’s can be isolated from stool by methods of microscopic examination, culture, PCR and toxin assay. However diagnosis is usually made based on symptoms and history of travel to developing nations.

If symptoms are persistent or severe then laboratory help is used to help diagnose the specific cause of illness.

Is there any treatment?

Antibiotics in the fluoroquinolone family like ciprofloxacin, levofloxacin, are effective; along with Azithromycin.

How long to Take it?

What to Take?When do I take it?How is it Given?Do I repeat it?More info
Zithromax (Pfizer)

With the onset of diarrhea

500 mg tablet by mouth once a day

a) if 1-3 loose stools/day take for 1 day b) if> 4 loose stools/day, fever or bloody stools take for 3 days

Levaquin (Ortho)

With the onset of diarrhea

500 mg tablet by mouth once a day

a) if 1-3 loose stools/day take for 1 day b) if> 4 loose stools/day, fever or bloody stools take for 3 days

Avelox (Bayer)

With the onset of diarrhea

400 mg tablet by mouth once a day

a) if 1-3 loose stools/day take for 1 day b) if> 4 loose stools/day, fever or bloody stools take for 3 days


What preventive measures can be taken?

Practices safe food precautions:


Wash your hands with soap and clean bottled water or antibacterial gel before eating

 Eat food that is cooked to order and brought to you steaming HOT!

Eat only well DONE meat, fish and eggs

Eat only undamaged fruit that you peel YOURSELF

And should NOT

Eat food sitting out at room temperature at stalls, buffets, counters etc.

Eat raw or undercooked meat, fish or eggs

Eat ice cream, soft cheeses or custard Drink cold milk, milkshakes or other dairy products

 Eat salads, precut fresh vegetables and fruits.

Practice safe water precautions:


Drink water that has been boiled for 3 minutes, OR

 Drink bottled water, from a bottle that has an unbroken cap seal, OR

 Drink water that has been purified with an ‘absolute less than 1 micron’ filter impregnated with iodine resin or add iodine tablets.

 Drink bottled water, juices, soda and alcohol directly from the container or through a straw; do not pour into wet glasses, cups and containers.

Brush your teeth and wash hands before eating with bottled water.

And should NOT

Drink tap water

Order ice with drinks, including alcoholic beverages

Brush your teeth or wash hands before eating with tap water

For more details go to our food safety and water safety sections.

What about antibiotics or other medications to ‘prevent’ travelers’ diarrhea?

Antibiotics are not routinely recommended to prevent travelers’ diarrhea, since such indiscriminate widespread use will result in the development of highly resistant bacteria; the best examples being E.coli resistant to Bactrim and Doxycycline, Campylobacter resistant to Ciprofloxacin, Malaria resistant to Chloroquine and Mefloquine, Methicillin Resistant Staphylococcus Aureus etc.

In addition the potential for side effects of allergic reactions, yeast infections, sun burn and paradoxically even antibiotic associated diarrhea would result in individual chasing new health problems with one pill after another pill.

However in select individuals with medical conditions that predispose them to severe illness or complications the benefit of antibiotics prophylaxis outweighs the risks. These include individuals who have:

Moderate to severe HIV disease with a CD4 count less than 350

Solid organ or bone marrow transplants

Active inflammatory bowel disease like Ulcerative colitis or Crohn’s

Severe heart or kidney disease and can become easily dehydrated.

The recommended medications are

Ciprofloxacin 500 mg by mouth once a day

Norfloxacin 400 mg by mouth once a day

Rifaximin 200 mg by mouth once a day

Pepto bismol 2 tablets by mouth 4 times a day

Are Probiotics helpful in preventing travelers’ diarrhea?

The specific agents Lactobacillus GG and Saccharomyces boulardii have shown some protective effect in travelers but studies were small.

Is there an effective vaccine to prevent travelers’ diarrhea?

Trials have shown that the Dukoral vaccine which is the B-Subunit whole cell cholera vaccine affords travelers some protection against Enterotoxigenic E. coli infection, due to some antigenic similarities. However estimates of it’s effectiveness to prevent travelers’ diarrhea as a whole was less than 7%, given that travelers’ diarrhea is caused by a multitude of pathogens.

Are there any long term complications from travelers’ diarrhea?

After any diarrheal illness whether obtained during travel or at state side, one can very rarely sees complications due to one’s immune reaction to the infection. After a diarrheal illness has resolved a minority of people may develop any one of the following:

Reiter’s syndrome characterized by pain involving the low back, hips and pelvis, redness of the eyes or painful urination.

Irritable bowel syndrome characterized by alternating constipation, diarrhea, cramps and bloating.

Guillain - Barre syndrome characterized by numbness, tingling, weakness and paralysis of the muscles that tend to progress in an ascending manner up the limbs (feet – hips, fingers - shoulders) and may involve the breathing muscles in severe cases.

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