Pathogenesis of traveler's diarrhea.

Diarrhea is the most common medical complication among persons venturing into tropical and semitropical regions of the developing world from industrialized regions. The illness is characteristically caused by one of a variety of bacterial agents, of which enterotoxigenic Escherichia coli is the most important. Intestinal electrolyte fluid movement explains the pathophysiology of most cases while in certain situations osmotic diarrhea or altered intestinal motility may lead to passage of unformed stools. In 1-2% of traveler, diarrhea lasts more than 1 month. Most of the patients will have diarrhea that is eventually self-limiting. The cause and mechanisms of diarrhea in these settings are largely unknown although a focal intestinal inflammation lesion may be found.