Introduction

Traveler’s diarrhoea (TD) is a common condition where the person frequently passes loose stools within a period of 24 hours, leading up to 2 weeks in severe cases. TD is the most common and frequent condition found among travellers travelling to different parts of the world, especially in unhygienic places. About 30-70% of people suffer from this condition.¹ People usually get diarrhoea by ingestion of food or drink contaminated with bacteria, viruses, or parasites. 

You can get a cholera vaccine before travelling as a prophylaxis and to improve immunity. Personal hygiene is also very important, and make sure to wash your hands frequently. There are also many guidelines for the treatment and prevention, which include antibiotics such as ciprofloxacin and azithromycin to alleviate the symptoms and treat the condition. Antibiotics given as prophylaxis treatment may contribute to the development of antibiotic resistance.

Symptoms of traveller’s diarrhoea

• Vomiting and nausea
• Bloating
• Watery stool
• Frequent bowel movement
• Blood in stool
• Abdominal Cramps
• Fever

Common causes

It can also be transmitted by touching unclean surfaces, improper food storage, and lack of cleanliness.

Bacteria

It is the most common cause, responsible for 30% of the cases.² It is mostly caused by the bacteria Escherichia coli, which produces enterotoxins, a powerful toxin that disrupts the activity of the gastrointestinal tract and causes diarrhoea. Other bacteria include Campylobacter jejuni, Shigella, and Salmonella. Bacterial diarrhoea has been reported to last for 3-7 days if left untreated.³

Viruses

Viruses are the second most common cause of travellers' diarrhoea. Traveller's diarrhoea caused by the virus shows the rapid onset of symptoms, with vomiting more exaggerated in the case of norovirus.⁴

Parasites

Parasites have a slow onset of symptoms, with loose stool 2-3 times a day. It generally lasts for a week or a month if left untreated.

Risk factors

Traveller’s diarrhoea is most common in areas with warm weather and unsanitary conditions, as it allows the pathogens to grow and multiply rapidly in a warm andPeople travelling in areas that lack resources, such as clean water, electricity, refrigerators, and clean storage space, are at high risk. 

People at risk are⁵

• People with low immunity
• People with chronic gastrointestinal issues
• People using Proton Pump Inhibitors 
• Children and infants
• In some cases, pregnant women
• Travelling to locations with an unsanitary and warm environment

How do pathogens cause diarrhoea

Enterotoxigenic Escherichia coli bacteria (ETEC) release enterotoxins, which contaminate food and water. Ingestion of contaminated water infects the Gastrointestinal Tract and disturbs the normal function, causing increased fluid secretion and decreased fluid absorption in the intestine, resulting in watery stool. The infection disrupts the fluid-electrolyte balance, causing pain and inflammation.⁶

Role of antibiotics in management

The antibiotics play a very significant role in the treatment of traveller’s diarrhoea. They kill the bacteria and stop their growth. They also ease the pain and help in rapid recovery. It will be ineffective to give antibiotics if diarrhoea is caused by a virus or parasites, and it will further contribute to antibiotic resistance.

Commonly used antibiotics

Fluoroquinolones

Fluoroquinolones are a class of antibiotics, bactericidal which kill bacteria by stopping bacterial DNA synthesis. They kill the bacteria and restore the normal function of the gastrointestinal Tract.

Fluoroquinolones include ciprofloxacin and Levofloxacin. Ciprofloxacin is usually prescribed in case of a moderate-to-severe condition.

• Ciprofloxacin dose: 500mg twice a day for 3 days
• Levofloxacin dose 500mg once a day for 3 days

However, it is always best advised to consult a physician or pharmacist.⁷

Contraindications 

Fluoroquinolones are contraindicated in

• Children under age 8 
• Pregnant women
• Breastfeeding women
• Patients with heart problems
• Kidney patients, diabetic patients 
• Epileptic patients⁸

Possible side effects

• Joint pain and swelling
• Difficulty walking
• Memory problems
• Fatigue
• Depression

Limitations 

Fluoroquinolones were 1st line of treatment for TD; however, due to rising resistance in Southeast Asia, it is not given as primary treatment anymore. 

Azithromycin

Azaithromycin is given as an alternative to those resistant to Ciprofloxacin. It shows bacteriostatic activity against bacteria, treats the person and eases the discomfort.

The recommended dose of Azithromycin is 500mg once a day for 3 days for adults.

For children, 5-10 mg/kg once a day for 3 days.⁹

Azithromycin can be given to pregnant women as it is considered safe, however, it is always best advised to consult your doctor or pharmacist.

Contraindications

It is contraindicated in

• People allergic to Azithromycin
• People with heart problems 
• Diabetic Patients
• Liver disease¹⁰

Side effects 

• Nausea
• Headache
• Vomit
• Loss of appetite 

Rifaximin

Rifaximin is an antibiotic used to treat traveller's diarrhoea as it is bacteriostatic; it stops the growth of the bacteria. Rifaximin has fewer side effects and drug interactions, so it is considered a safe drug. It is mainly used to treat acute cases of Traveller’s diarrhoea.

Rifaximin's recommended dose is 200 mg three times daily for three days.¹¹

Contraindications 

Rifaximin has an excellent safety profile and is safe to use, however, some contraindications are

• People allergic to rifaximin or Rifampicin
• People with liver damage

Side effects

Rifaximin is a safe drug with no or few side effects, which include:

• Nausea
• Stomach disturbance
• Fatigue
• Muscle pain

Antibiotic resistance and concerns

The antibiotics are effective in the treatment of traveller's diarrhoea, but some concerns regarding their use must be urgently addressed. Antibiotics such as ciprofloxacin were initially considered as the first line of the drug treatment for diarrhoea; however, due to their improper use, it is no longer effective in many parts of the world, contributing to antibiotic resistance. This occurs due to a lack of patient compliance and adherence. You must follow the instructions of your doctor and complete the antibiotic course even when you feel better, as it ensures complete eradication of the bacteria from the body. 

Antibiotics cannot be used to treat traveller's diarrhoea caused by viruses or parasites since they only show activity against bacteria. You must get a diagnosis and determine the cause of the diarrhoea If it is caused by bacterial infection, antibiotics must be prescribed.

Alternative and adjunctive therapies

Some of the alternatives other than antibiotics include:

Rehydration therapy (oral rehydration salts, IV fluids)

Travellers' diarrhoea causes the person to lose a lot of water from the body, which can result in weakness or severe dehydration. ORS solution can rapidly rehydrate the body and balance the electrolyte levels in the body.

Probiotics 

Probiotics help in the recovery of the gut flora or the “healthy bacteria” in the intestine and restores normal function in the gut, and improve the absorption of fluid to prevent watery stools. The most common probiotic is Lactobacillus.

Loperamide with antibiotics

Loperamide is an antimotility drug which decreases or slows the intestinal movement, thus decreasing the frequency of diarrhoea. It is co-administered with antibiotics to treat the condition readily. The dose given is 4 mg starting dose, followed by 2 mg after each unformed stool. The maximum dose must not exceed 8mg.¹²

It should not be given in case of bloody stools or fever, as it can further worsen the conditions.

Summary

Traveller’s diarrhoea is a very common condition found among travellers. The person ingests food contaminated with pathogens, which infects the intestine and causes watery stool. It mostly occurs in areas with warm, humid and unsanitary conditions. People show symptoms such as frequent stools, abdominal pain and bloating. Antibiotics used for this condition are Fluoroquinolones, Azithromycin and Rifaximin. Fluoroquinolones used to be the first line of treatment, but due to increasing antibiotic Resistance, Azithromycin is more frequently used now. Other alternatives to antibiotics include Rehydration therapy, Use of Probiotics and co-administration of loperamide with antibiotics; they are also effective in treating the complications associated with the disease.

Traveller's diarrhoea is not a life-threatening condition in most cases, and early treatment with antibiotics can rapidly improve the patient's health.