Prevention and treatment of travellers' diarrhoea

Travellers’ diarrhoea (TD) is the most predictable travel-related illness. Attack rates range from 30% to 70% of travellers, depending on the destination. Poor hygiene practice in local restaurants is likely the largest contributor to the risk for TD. Bacterial pathogens are the predominant risk, thought to account for 80%–90% of TD. Intestinal viruses have been isolated in studies of TD, but they usually account for 5%–8% of illnesses. Protozoal pathogens are slower to manifest symptoms and collectively account for approximately 10% of diagnoses in longer-term travellers. Overall, the most common pathogen is enterotoxigenic Escherichia coli, followed by Campylobacter jejuni, Shigella spp., and Salmonella spp. Enteroadherent and other E. coli species are also common pathogens in bacterial diarrhoea. There is increasing recognition of Aeromonas spp. and Plesiomonas spp. as causes of travellers’ diarrhoea as well. Viral diarrhoea can be caused by a number of viral pathogens, including norovirus, rotavirus, and astrovirus. Giardia is the main protozoal pathogen found in TD. Entamoeba histolytica is a relatively uncommon pathogen in travellers. Cryptosporidium is also relatively uncommon. The risk for Cyclospora is highly geographic and seasonal

The world is generally divided into 3 grades of risk: low, intermediate, and high.

  • Low-risk countries include the United States, Canada, Australia, New Zealand, Japan, and countries in Northern and Western Europe.
  • Intermediate-risk countries include those in Eastern Europe, South Africa, and some of the Caribbean islands.
  • High-risk areas include most of Asia, the Middle East, Africa, Mexico, and Central and South America.

Chemoprophylaxis
Most guidelines do not recommend prophylaxis for the typical traveller because of potential adverse drug effects while away from medical care and because effective rapid onset therapy is available for diarrhoea should it occur. However, chemoprophylaxis can be considered for travellers with advanced human immunodeficiency virus (HIV) infection, for those who have an underlying chronic medical problem that makes them more prone to adverse consequences from diarrhoea, and for travellers on a vital mission for a short period (less than 1 week) who cannot tolerate even a day of disability. Antibiotic prophylaxis should be carried out with a quinolone once per day or with rifamixin if travel is to an E. coli–predominant area; prophylaxis should only be used for trips of 2 weeks or less.

Self-Treatment of Traveller’s Diarrhoea
All travellers to the developing world should be thoroughly educated in self-therapy for diarrheal disease and carry the appropriate agents while travelling. Eighty percent of patients respond to an antibiotic within 24 hours. A single dose of a self-administered quinolone is usually sufficient, but patients should be instructed to complete 3 days of therapy with 500mg of levofloxacin each day or 500mg of ciprofloxacin twice daily should the TD not resolve within 24 hours. Because of a significant increase in quinolone resistant Campylobacter in Southeast Asia, India, and Nepal, travellers to those destinations should self-treat with azithromycin, 500mg per day for 3 days, or a single dose of 1000mg. Instructions on when to seek medical care should be given. Rifamixin can be used for TD caused by E. coli in adults and can be carried to E. coli-predominant areas but is not recommended when the patient has fever or blood in the stool.

STMIDI recommends Azithromycin 1000mg single dose or 500mg daily for 3 days for travelling in India will be better in view of high occurrence of cholera. Anti secretory agents like Loperamide is indicated by some guidelines because of symptomatic relief achieved by them.