While traveler’s diarrhea and food poisoning are not completely avoidable, there are several ways in which you can stay informed on the origin and mechanisms of these conditions, as well as any precautions you can take that might protect you in the future.

What is Traveler’s Diarrhea?

Traveler’s diarrhea is one of the most common medical conditions that will occur to international travelers every year. By definition, traveler’s diarrhea must first be characterized as either mild, moderate or classical in nature.

• Mild Diarrhea 
  • 1-2 loose stools each day
  • No other gastrointestinal (GI) symptoms present
• Moderate Diarrhea
  • 1-2 loose stools each day with at least 1 other GI symptom is present
  • Can also involve at least 3 loose stools each day without the presence of other GI symptoms
• Classical Diarrhea
  • Three or more loose stools each day
  • Accompanied by at least 1 other GI symptom
• Possible GI Symptoms to Accompany Traveler’s Diarrhea:
  • Nausea
  • Vomiting
  • Abdominal pains
  • Cramps
  • Fever
  • Blood in the stool (melena) ¹

Who is at Risk?

Today it is easier than ever before for people to travel to almost any country in the world. In fact, it is estimated that every year almost 80 million travelers from industrialized countries will travel to tropical countries ¹.

While improvements in aviation technology have allowed for people to experience new cultures and help less fortunate communities in poorer countries, it has also led international travelers to often be at high risk for travelers’ diarrhea. The vulnerability of international travelers to this condition is a result of their immune system’s inexperience with the infections that exist in foreign countries.

As a result of the likelihood of traveler’s diarrhea, it is extremely important for travelers to consider the following questions prior to their takeoff:

1. What is your country of origin?

If the traveler is from a highly industrialized country, like the United States or England, there is a much higher chance that, when staying in a developing country, the traveler will get traveler’s diarrhea.

 2. What are the hygienic conditions of the country you will be visiting?

Some of the most important factors that travelers must consider before traveling to developing countries, particularly those located in Africa, Central and South America, as well as South, Central, and West Asia, include:

• Availability of appropriate medical care
• Safety and purity of antibiotics in the destination country
• Hygienic conditions of where you will be staying

 3. How long will you be visiting the country?

• Various studies have compared how the traveler’s duration of stay can affect their susceptibility to suffering from the symptoms of traveler’s diarrhea.
• Overall, these studies have found that people traveling to developing countries for shorter periods of time (several days up to a month) are at a significantly greater risk of developing diarrhea as compared to travelers who remain in their destination country for a month or longer.

World Map of Risk Regions

The country that you are traveling to plays a crucial role in determining exactly how much of a risk you are at coming into contact with diarrhea-causing bacteria. This correlation between destination country and traveler’s diarrhea is strongly influenced by warmer climates, such as those which are common to tropical and subtropical areas.

Additionally, the hygienic standards that exist in these countries also play a determining factor in protecting travelers against diarrhea and other uncomfortable GI symptoms. It is also important to realize that high-risk countries, as shown in the map below, are also unfortunately home to higher childhood diarrhea mortality rates.

From the map shown above, three different types of geographical regions have been differentiated by evaluating the risk of traveler’s diarrhea that is associated with each country. These risks include:

	CHANCE OF GETTING TRAVELER’S DIARRHEA	AFFECTED REGIONS
Low-Risk Areas	Less than 8%	Central EuropeNorthern Europe The United States of America Canada Japan Australia
Intermediate-Risk Areas	8% – 20%	Southern EuropeEastern Europe Russia China Israel The Caribbean South Africa
High-Risk Areas	20% – 90%	Middle-EastSouthern Asia Central America South America Africa

 

What Causes Traveler’s Diarrhea?

Traveler’s diarrhea is almost always the result of contamination by an infectious organism, which include various bacteria, viruses, and parasites. When these infectious agents enter your digestive systems, such as through the ingestion of contaminated food or water, they can cause a cascade of GI symptoms to follow, most of which are highly unpleasant and can often prevent you from doing much at all during your travels.

Bacterial Pathogens

There are thousands of “antibacterial” products available on the market in the form of soaps, hand sanitizers, mouthwashes, toothpastes, disinfectants and much more.

But what exactly are these antibacterial products protecting us against?

Bacteria are single-cell organisms (unlike humans, which have millions of different types of cells in our bodies) that can live in soil, the ocean, and even inside of our GI tract. Although a proper amount of bacteria living inside of our guts helps ensure that we are properly digesting food, the unwanted invasion of these bacterial species into our bodies can be very destructive.

Bacterial traveler’s diarrhea, if left untreated, typically lasts for 3-7 days. Here are some of the most common bacterial species that play a role in traveler’s diarrhea:

Escherichia Coli (E. coli)

In the United States alone, there have been over thirty E. coli outbreaks that have taken place over the past few decades. E. coli species play a significant role in promoting the occurrence of traveler’s diarrhea in developing tropical and semitropical regions.

There are two major types of E. coli strains:

• Enterotoxigenic E. coli (ETEC) 
  • A major cause of diarrhea in children in developing countries
  • Responsible for up to 60% of traveler’s diarrhea cases in all developing tropical and semitropical regions ¹
  • Common to most regions of South and Central America, the Caribbean, as well as many parts of Asia and Africa

• Enteroaggregative E. coli (EAEC)
  • Estimated to account for as many traveler’s diarrhea cases as ETEC
  • Persistent in children’s diarrhea in developing country and AIDS-associated chronic diarrhea

Shigella

An infection that is a result of the invasion of the Shigella species of bacteria is also referred to as shigellosis. This type of diarrheal condition exhibits some key symptom features, of which can include:

• Bloody diarrhea
• Watery diarrhea
• Abdominal pain
• Fever
• Malaise (discomfort)

Here are some key features of Shigella bacteria:

• Typically occurs in young children, with a peak in preschool students
  • Suggests that increased exposure to Shigella increases the body’s ability to develop immunity to this bacteria species
• Responsible for up to 10% of traveler’s diarrhea in developing countries ¹
• Readily spreads among individuals living in cramped and over-crowded spaces
• Can be spread through the following routes:
  • Water contamination
  • Food contamination
  • Person-to-person spread
  • Flies1

Salmonella

It is important to recognize that nontyphoidal salmonellosis, which is the condition in which an individual is exposed to and suffers from the symptoms of Salmonella poisoning, is very different that typhoid fever that is caused by Salmonella typhi.

Here are some key features of Salmonella infection:

• Typically occurs as a result of ingesting contaminated food or water
• Particularly prevalent in animals raised for food
  • Aside from occurring in live animals, food products from these animals can become contaminated during collection and processing by food handlers
• Accounts for up to 10% of traveler’s diarrhea cases in developing countries ¹
• Peak seasons of Salmonella outbreaks in the United States: summer and fall
  • Often the result of inadequate cooking techniques at barbeques and picnics during these seasons
• Highest rates of Salmonella infection occur in children under the age of 5 and the elderly

Campylobacter

Of the various species of Campylobacter that exist, Campylobacter jejuni is one of the most commonly identified bacterial origins of acute gastroenteritis in the world. In developing countries, campylobacteriosis, which is the term used to describe the condition that results from Campylobacter exposure, affects individuals of all ages.

Here are some important facts on Campylobacter and its relationship to traveler’s diarrhea:

• Infection by Campylobacter is more likely to occur in the summer than in the winter
• Typically found in wild and domestic animals, particularly birds
  • Chickens are the largest source of infection by Campylobacter
• Can account for 10-50% of traveler’s diarrhea cases, depending upon the destination country ¹
• Typically results from the ingestion of contaminated food or water
  • Particularly poultry meat
  • Raw milk

Viral Pathogens

Some of the most common viral infections include the influenza virus, hepatitis, dengue fever and severe acute respiratory syndrome (SARS).  Viral traveler’s diarrhea, if left untreated, typically lasts for 2-3 days. There are three main virus classifications, of which include: 

• Calicivirus

• Norovirus

• Rotavirus
  • Most common cause of dehydrating diarrhea of young children in the world
  • A major cause of death in children under 5 around the world
  • Diarrhea lasts longer than other viruses (4 days or more)

• Astrovirus
  • One of the most common causes of viral diarrhea in infants and children
  • Associated with gastroenteritis in people with immunodeficiencies
• AIDS

• Enteric Adenovirus
  • Person-to-person transmission
  • Not typically related to food or water contamination ¹

Parasitic Pathogens

Approximately 30% of all physician visits that travelers will take following their return home from developing countries will be from diarrhea caused by parasites. As compared to bacterial and viral diarrhea, traveler’s diarrhea that occurs as a result of parasitic invasion can last for weeks to months if left untreated.

The most common parasites that account for traveler’s diarrhea include:

• Giardia lamblia
• Entamoeba histolytica ¹

Treatment Options

In addition to the treatment options that specifically target the type of organisms that have caused traveler’s diarrhea to occur, there are various universal treatment options that are highly recommended for any individual suffering from traveler’s diarrhea. These universal treatment options include:

• Oral Rehydration Therapy

  • Replenishes any fluids and electrolytes that were lost during diarrhea episodes
  • Especially important for affected young children or adults with chronic medical illnesses
  • Helps traveler’s feel better more quickly
  • Commercial products:
  • Electrolyte Gastro
  • Pediatric Electrolyte Freezer Pops
  • Pedialyte
  • Can also be made at home

• Antimotility Agents

  • Provide symptomatic relief
  •  Examples:
    • Loperamide (Immodium)
    • Diphenoxylate

ORGANISM	TREATMENT OPTIONS
Bacterial Organisms	Antibiotics Fluoroquinolones (depends on the destination because of possible resistance) Ciprofloxacin Levofloxacin Azithromycin Rifaximin (safest side effect profile)
Viral Organisms	Bismuth Subsalicylate (BSS)
Parasitic Organisms	Metronidazole Tinidazole Nitazoxanide Trimethoprim-sulfamethoxazole (TMP-SMX) Iodoquinol Paromomycin 3

Traveler’s Diarrhea and GI Disorders: The Connection

The association between traveler’s diarrhea and GI disorders, particularly irritable bowel syndrome (IBS), has been investigated since the early 1960s when researchers Chaudhary and Trulove associated the onset of IBS symptoms in patients who had previously recovered from dysentery.

As research in this area continued to progress, researchers termed this condition as postinfectious irritable bowel syndrome (PI-IBS), which describes individuals with IBS who have been shown to develop their symptoms following an episode of infectious gastroenteritis ¹.

One of the ways to differentiate PI-IBS from other forms of IBS is through the following parameters:

• Patients without a history of onset GI symptoms, persistent abdominal discomfort or pain, and altered bowel habits should be considered for PI-IBS diagnosis.
• IBS patients without infectious onset are more likely to have alternating bouts of diarrhea and constipation; whereas PI-IBS patients will predominantly suffer from diarrhea as compared to other potential GI symptoms
• It is estimated that 10% of people who get severe food poisoning will develop PI-IBS or small intestine bacterial overgrowth (SIBO)

Protecting Yourself from Traveler’s Diarrhea

Food and Water Hygiene

Since most traveler’s diarrhea cases result from the ingestion of contaminated food and water, it is important for travelers to be educated on how they can reduce their risk of exposure to these pathogens. While this type of education is important, it should still be noted that travelers do not have much control over various factors, such as the hygiene of a restaurant, that can still expose them to potentially harmful pathogens.

Here are some useful tips that you can consider before planning your next trip:

• Consume peeled fruits and vegetables
• Consumed fully cooked food
• Consume pasteurized dairy products
• Never drink tap or well water, or any product that has been made using water from these sources (e.g., ice and juice).
  • Always drink bottled or sealed water that has been boiled, filter or treated in some other way.
  • If bottled water is not available or reliable, researchers suggest that travelers drink carbonated bottled water.
    • Carbonated water is more acidic in nature, which can add an antibacterial effect to the water.
• Be aware of the source of your food in other countries. For example, buying a meal from a street vendor may increase your risk of ingesting contaminated food.

Handwashing

Although this cannot prevent invasion by all traveler’s diarrhea sources, handwashing immediately before eating is still a good habit for all travelers to practice when in their destination country. Furthermore, handwashing immediately after using the restroom, especially after defecation, can also reduce the risk of travelers to diarrhea.

If you do not have access to a bathroom to wash your hands while traveling, it is highly recommended to always keep alcohol-based hand sanitizers, or other types of solutions, with you at all times, as these solutions have been shown to be just as good, or even better, than traditional handwashing with water and soap.

Prophylactic Drug Strategies

Aside from educating yourself about the do’s and don’ts before leaving for your travel destination, it is important for you to also realize that there are several prophylactic drugs that have been shown to be effective in preventing traveler’s diarrhea.

A prophylactic drug is a medication that is taken in an effort to prevent a disease, which is different than most other types of medication that are taken after a disease has already been acquired.

While there is some debate as to the actual success of prophylactic drugs while traveling, the National Institutes of Health Consensus Development Conference in 1985 did recommend the use of these drugs for the following travelers:

• Travelers with stringent schedules
  • Diplomats
  • Musicians
  • Lecturers
• Travelers with a history of frequent traveler’s diarrhea
• Travelers with chronic medical conditions, such as:
  • Chronic gastrointestinal, immunologic, endocrinologic and hematologic disorders ¹

It is also important to recognize that, while this has not been completely validated by scientific studies, researchers expect that the use of prophylactic drugs can have a role in preventing postinfectious IBS.

Types of Prophylactic Drugs

PROPHYLACTIC DRUG	DESCRIPTION	RECOMMENDED DOSAGE
BSS-containing compounds	E.g., Pepto-Bismol, Kaopectate and Bismatrol Anti-inflammatory Anti-secretory Anti-microbial Accounts for a majority of this drug class’ ability to prevent traveler’s diarrhea Can provide protection against traveler’s diarrhea by as much as 65%	8 tablets dailyNote: Speak with your doctor if you take aspirin, as these high doses of salicylate can cause toxic effects
Tannin Albuminate + Ethacridine Lactate	Tannin albuminate is an absorbent(absorbs toxic substances) Ethacridine lactate is an antiseptic drug(prevents growth of disease-causing microorganisms) Has been associated with up to a 36% protection rate in travelers	500 mg of tannin albuminate and 50 mg of ethacridine lactate twice a day was found to reduce traveler’s diarrhea in a previous study; however, further studies need to be tested to determine exactly what regimen is recommended for this prophylactic treatment option.
Probiotics	E.g., Lactobacillus, Bifidobacterium bifidum and Sacharomyces boulardii Based on the thought that by introducing bacteria or yeast strains into the gut, these ‘healthy’ bacteria will be able to interfere with the colonization of bacteria that you may come into contact when traveling and consuming potentially contaminated food	No exact dosage has been established; however, studies have found that 2 x 109bacteria of Lactobacillus was found to be successful in reducing traveler’s diarrhea in one study 4.
Antibiotics	E.g., Doxycycline, TMP-SMX, azithromycin and rifaximin	Varies depending upon the type of antibiotic used: (QD means once a day)*Rifaximin is minimally absorbed vs the other systemic antibiotics  Fluoroquinolones (400 mg QD) Norofloxacin (300 mg QD) Ofloxacin (500 mg QD) Ciprofloxacin (500 mg QD) Levofloxacin (500 mg QD) Rifaximin (200 mg twice a day) 6

Challenges with Prophylaxis Treatment

There are several arguments that researchers have against the use of prophylactic drugs. Aside from the potential adverse effects of these drugs, which can include rashes, yeast infections in women and the onset of some GI symptoms, various other concerns of the use of prophylactic drugs include:

• Interfering with natural immunity

  • If you are staying in a country for longer than one month, it may actually improve your immunity of being exposed to these types of pathogens

• Antibiotic Resistance

  • More common in developing countries as compared to developed countries ¹
    • This is often because drugs in developing countries can be purchased without requiring a prescription from a physician ¹

How to Protect Yourself at Home

It is important to realize that diarrhea that results from food contamination can also occur while at home in developed countries.

Below are the basic steps to take to avoid food poisoning at home:

Handwashing

To avoid bacterial, viral, or parasitic diarrhea from occurring, it is crucial for people to wash their hands well during food preparation. This becomes an even more important protective measure when handling raw meat and vegetables, as well as using the bathroom or petting an animal, as each of these sources can play a contributing role to the occurrence of diarrhea.

Put Leftovers Away

If you have cooked food that you want to save for later, make sure you do not keep leftovers at room temperature for more than two hours before putting them in the fridge. The longer food is left out will increase the chance of microorganisms growing on your food.

Keep Your Fridge Clean

It is extremely important to immediately clean up any food or drinks that spill in your fridge with a suitable detergent. Fridges should be cleaned fully as often as necessary, as well as deep cleaned at least once a year.

Monitor Your Fridge’s Temperature

The coldest part of your fridge should be kept at a temperature between 0 and 4°C. Also, make sure to check the door seals to ensure they’re still airtight. By keeping your refrigerator at the correct temperature, your food will be able to stay fresh and prevent the unwanted invasion of microorganisms.

Use Separate Cutting Boards

You should use one chopping board for raw meat and fish, and another for cooked foods and clean vegetables. And once your food is cooked, make sure not to reuse the dishes or utensils you used to carry or handle the raw ingredients.

Cook Meat Thoroughly

To protect yourself from harmful infectious organisms, cook all of your meat products thoroughly. This is especially when young children, pregnant women, and people with weakened immune systems will be consuming these food products, as undercooked foods, such as a rare meat patty, could potentially carry harmful microorganisms.

When in Doubt, Avoid Raw Foods

Although raw food can be safe to eat, there is always a level of uncertain risk associated with these food products. Children, pregnant women, and people with weakened immune systems are strongly advised to avoid raw meat and fish (carpaccio, ceviche, sushi, etc.) and unpasteurized dairy products. Freezing fish for seven days is an effective way of killing parasites (such as Anisakis). With fresh produce, it is recommended that consumers check the label prior to freezing. Additionally, avoid refreezing products that have already been thawed.