Traveller's diarrhoea- Caring for your gut while you travel

Traveler's diarrhea is a disorder of the digestive tract that typically causes loose stools and abdominal discomfort. It is caused by consuming or drinking contaminated food or water. Fortunately, most cases of traveler's diarrhea are not severe; they are merely unpleasant.

There is an increased risk of developing traveler's diarrhea when you travel to a location with a climate or sanitation practices that differ from your own.

To reduce your risk of traveler's diarrhea, be careful about what you consume and drink while traveling. If you develop traveler's diarrhea, it will likely resolve without treatment. However, it is prudent to bring doctor-approved medications when traveling to high-risk areas. Thus, you will be prepared in the event that diarrhea becomes severe or persistent.

Who is at risk of suffering from traveler's diarrhea?

A gastrointestinal infection can occur anywhere and to anyone. At home, we may refer to the condition as food poisoning or gastric flu. During international travel, however, you are more likely to be exposed to pathogens that are transmitted less frequently at home. Traveler's diarrhea is a readily identifiable gastrointestinal infection that can occur while traveling or shortly after returning home.

Each year, millions of international tourists contract traveler's diarrhea. High-risk areas for developing traveler's gastroenteritis include:

• The region of Central America.
• Latin America.
• Mexico, then Africa.
• Southeast Asia and South Asia.
• Eastern Europe, South Africa, Central and East Asia, the Middle East, and a handful of Caribbean islands are also risky destinations. However, in Northern and Western Europe, Japan, Canada, Singapore, Australia, New Zealand, and the United States, the risk of traveler's diarrhea is generally low.

Your likelihood of developing traveler's diarrhea depends largely on your destination. However, certain populations have a higher risk of developing the condition. These consist of:

• Teens and young adults. The condition is more prevalent among young adult visitors. It is plausible that young adults lack acquired immunity, although the reasons for this are unclear. They may also be more daring in their travels and dietary preferences than their elders, or they may be less cautious about averting contaminated foods.
• Those with a compromised immune system. A compromised immune system due to an underlying illness or immune-suppressing medications such as corticosteroids increases the likelihood of contracting an infection.
• Diabetes, inflammatory bowel disease, and severe kidney, liver, or cardiac disease patients. These conditions can increase your susceptibility to infection or the likelihood of a more severe infection.
• Those who take acid-blocking or antacid medications. The acid in the stomach tends to kill organisms, so a decrease in stomach acid may increase the likelihood of bacterial survival.
• Those who travel during particular seasons. Season affects the risk of traveler's diarrhea in certain regions of the globe. For example, risk is highest in South Asia during the sweltering months just before the monsoons.

Signs and symptoms of traveler’s diarrhea

The onset of traveler's diarrhea may occur suddenly during your excursion or soon after your return. Without treatment, the majority of individuals improve within one to two days and recover completely within one week. However, multiple episodes of traveler's diarrhea are possible during a single excursion.

These are the most prevalent symptoms of traveler's diarrhea:

• Passing three or more looser, more watery stools per day.
• An urgent need to defecate.
• Abdominal pains.
• With nausea.
• The act of vomiting.
• High temperature.
• Occasionally, individuals experience moderate to severe dehydration, persistent vomiting, a high fever, bloody stools, or severe abdominal or rectum discomfort. 
• If you or your child experience any of these symptoms, or if diarrhea persists for more than a few days, you should consult a doctor.

How does traveler’s diarrhea occur? 

Most frequently, travelers' diarrhea is transmitted via fecal-oral transmission of the causative organism, typically via consumption of contaminated food or water.  Depending on the causative agent, the incubation period can range from 6 to 24 hours for viruses and bacteria to 1 to 3 weeks for intestinal parasites.  

The pathophysiology of traveler's diarrhea varies depending on the causative agent but can be subdivided into non-inflammatory and inflammatory pathways. Non-inflammatory agents reduce the intestinal mucosa's absorption capacity, thereby increasing the outflow of the gastrointestinal (GI) tract.

What is the duration of traveler's diarrhea?

Within two to three days, your symptoms will typically begin to resolve on their own. If you have the most common type of infection, a bacterial infection, you may continue to experience symptoms for up to a week. Without treatment, parasitic infections can last from weeks to months. If your symptoms are not resolving, you may be suffering from a parasite infection.

When to see a physician for traveler’s diarrhea?

Typically, traveler's diarrhea resolves on its own within a few days. If caused by specific microbes or parasites, the duration and severity of symptoms may be prolonged. In such instances, you may require prescription medications to recover. 

• Your diarrhea has lasted more than two days.
• You develop dehydration.
• You suffer from severe abdominal or rectal discomfort.
• Bloody or black stools are present.
• You have a fever greater than 102 degrees Fahrenheit (39 degrees Celsius).

Be especially cautious around children, as traveler's diarrhea can rapidly cause severe dehydration. Consult a physician if your child has any of the following symptoms:

• Continual regurgitation.
• A temperature of 102 degrees or higher.
• Bloody bowel movements or severe diarrhea.
• Oral dehydration or weeping without tears.
• Unusually lethargic, drowsy, or unresponsive behavior.

What complications are associated with traveler's diarrhea?

The most prevalent complication of persistent diarrhea is dehydration caused by fluid loss. Mild to moderate dehydration can result in irritating symptoms, but severe dehydration can be life-threatening, particularly for children. Children become dehydrated more promptly and severely than adults, and they do not recover as readily. They may require hospitalization to receive intravenous fluid replacement.

Examples of signs of dehydration include:

• Dry tongue, mouth, and cheeks.
• With sunken eyes.
• Too little or too dark urine.
• Experiencing headaches.
• a feeling of dizziness.
• There is confusion.
• Weakness due to fatigue.
• Lack of strength.
• Muscle spasms.
• Postinfectious disorders

Less frequently, healthcare professionals have observed that traveler's diarrhea can occasionally induce an underlying gastrointestinal disease. In some individuals, the symptoms of traveler's diarrhea persist after the infection has been eliminated. When no other cause can be identified, post-infectious irritable bowel syndrome (PI-IBS) is diagnosed. In other cases, individuals who were genetically predisposed to inflammatory bowel disease may develop their first symptoms following a bout of traveler's diarrhea.

What is the most effective treatment for travelers' diarrhea?

When healthcare professionals do prescribe medication for traveler's diarrhea, two categories are prescribed.

Antidiarrheal agents

Antidiarrheal drugs treat diarrhea, but not the underlying infection. They can alleviate your pain, but they can also prolong your illness. They function by reducing your motility — the muscle contractions that move your bowels — allowing your intestines to absorb more water from your feces. However, this also means that infectious organisms remain in your intestines for longer.

Antidiarrheals prescribed frequently include:

• The medication Loperamide (Imodium).
• Atropine diphenoxylate (Lomotil).

Antibacterial agents

In certain cases, your doctor prescribes antibiotics to treat the infection. Infections caused by parasites may necessitate antibiotics. Antibiotics may also be used to treat infections that are more severe. If you have a fever, more than three loose stools per day, or if there is blood or mucous in your stools, your symptoms are severe. Antibiotics may also be prescribed to those with compromised immune systems.

Antibiotics commonly prescribed include:

• Ciprofloxacin (Cipro) is an antibiotic.
• Levofloxacin (Levaquin) is a type of antibiotic.
• The antibiotic Azithromycin (Zmax).
• The drug Rifaximin (Xifaxan).
• Metronidazole (Flagyl).
• The drug Nitazoxanide (Alinia).

Natural antibiotics such as oil of oregano and echinacea extract with goldenseal can eradicate numerous pathogens, including the ones infecting you. Because traveler's diarrhea is typically a short-lived infection, it is difficult to determine how much they assist. These medicines may be most effective when used prophylactically. However, consult your doctor first to ensure that they are safe for you.

Preventive measures for traveler’s diarrhea

Observe what you eat

The general rule of thumb when traveling abroad is to boil, simmer, peel, or leave food alone. However, it is still possible to become ailing despite following these guidelines.

Other suggestions that may help reduce your likelihood of becoming ill include:

• Do not ingest food offered by strangers.
• Milk and dairy products, including ice cream, that have not been pasteurized should not be consumed.
• Do not consume uncooked or undercooked meat, seafood, or shellfish.
• Do not consume at room temperature moist foods such as condiments and buffet offerings.
• Consume foods that are properly prepared and served heated.
• Stick to self-peeling fruits and vegetables, such as bananas, oranges, and avocados. Avoid salads and fruits that cannot be peeled, such as grapes and berries.
• Be aware that drinking alcohol will not protect you from contaminated water or ice.

Do not consume unclean water

Keep the following in mind when traveling to high-danger areas:

• Do not consume unfiltered water from the faucet, well, or stream. If you must drink local water, you should boil it for three minutes. Allow the water to chill naturally, then store it in a clean container with a lid.
• Don't use locally made ice cubes or consume mixed fruit juices made with tap water.
• Fruit that may have been rinsed in contaminated water should be avoided.
• To mix infant formula, use bottled or boiled water.
• Order beverages such as coffee and tea and ensure that they are piping hot.
• You may consume canned or bottled beverages in their original packaging, including water, carbonated beverages, beer, and wine, so long as you burst the seals yourself. Before imbibing from or pouring from a can or bottle, wipe it clean.
• Use bottled water for tooth brushing.
• Do not swim in potentially contaminated water.
• Maintain a closed mouth while bathing.

Takeaway

Typically, traveler’s diarrhea is not serious and passes rapidly. The most prevalent offenders are E. coli bacteria, followed by Salmonella. While traveling abroad, you can reduce your risk of infection by practicing excellent hygiene and being cautious about what you eat and drink. However, even with precautions, it is still possible to contract the disease.

References:

1. https://www.mayoclinic.org/diseases-conditions/travelers-diarrhea/symptoms-causes/syc-20352182
2. https://my.clevelandclinic.org/health/diseases/7315-travelers-diarrhea
3. https://www.ncbi.nlm.nih.gov/books/NBK459348/
4. https://www.hopkinsmedicine.org/health/conditions-and-diseases/travelers-diarrhea 

the polarization of macrophages, mediated by gut-derived LPS and its metabolites SCFA, plays a key role in the regulation of inflammatory diseases. On the other hand, macrophages are the main players in ensuring intestinal homeostasis through pathogen recognition and elimination and production of anti-inflammatory cytokines.

Immunity - Gut microbiome 

- The gut microbiota can regulate not only the local intestinal immune system but also can have a profound influence on systemic immune responses.

- Gut microbiota influences the development and function of immune cells, including antigen-presenting cells, T cells, B cells, and more. 

- The absence of a microbiota, as observed in germ-free animals, leads to significant alterations in immune cell populations and functions, emphasizing the critical role of the gut microbiota in maintaining immune homeostasis.

- This research provides valuable insights into the dynamic interplay between our gut microbiome and the immune system, shedding light on potential therapeutic avenues for immune-related disorders.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3337124/