Travellers' Diarrhea (TD) most often stems from having come into contact with food-borne pathogens. Perhaps as many as 70% of the cases of TD are due to infections by strains of pathogenic E.coli bacteria. Other bacteria, such as Salmonella and Shigella, are the infectious agents in a certain number of instances. Viral infections such as the Norwalk virus and Rotavirus can also develop into TD¹. TD usually lasts for three to five days; however, about 20% of infections will be severe enough to require that the person be confined to bed, and in about 10% of all cases the illness lasts for longer than a week. The acidic pH of the stomach and colon normally offers a natural form of protection against microbes, but this can be compromised by a number of factors: taking antacids, or histamine H2 blockers, for example, or having a decreased level of symbiotic bacteria in the colon. When infectious organisms are able to elude the body’s natural defenses, they proliferate in the microbial flora. Some produce proteins that help themselves adhere to the walls of the intestine, crowding out the beneficial flora, while others can produce toxins, cause inflammation, or cross the gastrointestinal barrier, all of which disrupts intestinal function. These cause increased fluid in the intestine and/or decreased absorption, resulting in diarrhea. Dehydration can follow, along with the loss of nutrients and electrolytes. Although TD can be severely debilitating, most cases are self-limiting. Restoring a natural equilibrium to the body’s microbial flora is synonymous with recovery.

• 1. Yates J. Traveller’s Diarrhea. Am Fam Phys. 2005. 71:2095-2100