Diarrheal disease is a significant cause of morbidity and mortality worldwide Diarrhea is often accompanied by other clinical signs and symptoms including vomiting, dehydration, fever, and electrolyte abnormalities There exist more than 40 different enteropathogens that can cause gastroenteritis and is neither possible nor necessary to arrive at an etiologic diagnosis in all cases Current Evidence Many children who travel to developing countries develop diarrhea Most episodes of traveler’s diarrhea resolve during or shortly after the travel Five percent to 10% of travelers report diarrhea that lasts for weeks or longer and 1% to 3% have diarrhea that lasts weeks or longer In the majority of cases, the etiologic agent of traveler’s diarrhea cannot be isolated However, among cases in which a pathogen is isolated, 50% to 75% are identified within weeks of developing symptoms As the duration of the diarrhea increases (typically greater than weeks), the likelihood of identifying a specific bacterial cause decreases; in contrast, the likelihood of identification of a parasitic cause increases The most commonly identified parasitic infections include G lamblia, Cryptosporidium parvum, E histolytica, and Cyclospora cayetanensis, although these are detected in less than one-third of travelers with chronic diarrhea and in only 1% to 5% of travelers with acute diarrhea Infected children are predominantly asymptomatic, but bloody or nonbloody diarrhea, hepatobiliary symptoms, and failure to thrive may occur Viral hepatitis should be considered when evaluating a child with nonspecific gastrointestinal symptoms, particularly when jaundice is present Hepatitis A is prevalent in both developed and developing nations and is acquired through contaminated food and water Hepatitis A is usually asymptomatic or manifests as mild symptoms in young children Hepatitis E must be considered because it is a common etiology of acute hepatitis in developing countries Although rarely presenting acutely, hepatitis B and C are common in the developing world and should be considered in any adolescent or young adult who is sexually active or has had a tattoo or body piercing while traveling There are several common noninfectious causes of chronic diarrhea in travelers including tropical sprue, postinfectious disaccharidase deficiency, and irritable bowel syndrome Tropical sprue is characterized by acute or chronic diarrhea, weight loss, and malabsorption of nutrients It occurs in residents of or visitors to the tropics and subtropics; the cause is unknown e-Table 94.20 reviews the differences between inflammatory and noninflammatory diarrhea Importantly, a diarrheal illness that develops more than month after travel is not likely due to travel exposure Goals of Treatment The goal is for the clinician to know in which children bacterial or protozoal pathogens would be a more likely etiology for diarrheal disease, and, therefore, which children would be more likely to benefit from antibiotic therapy Clinical Considerations Clinical recognition: Invasive or inflammatory enteropathy (e.g., dysentery) should be suspected in persons with bloody diarrhea, fever, or leukocytes detected in the mucous portion of the stool Invasive enteropathy has a fairly abrupt onset (over a period of hours generally) and may be complicated by metastatic infections, reactive arthropathy, or, in the case of infection with Campylobacter jejuni, Guillain–Barré syndrome Amoebic dysentery, caused by E histolytica among other amoebae, often presents slowly over the course of days and may be complicated by hepatic abscess formation Triage considerations: Early recognition of the dehydrated child, or of the child with possible electrolyte disturbances, is essential While most children with mild or moderate dehydration will respond to oral volume resuscitation, parenteral resuscitation will be needed for the severely dehydrated child Clinical assessment: Returning travelers with diarrhea should have stool samples cultured for enteric pathogens and examined microscopically for ova and parasites if there is evidence of an invasive enteropathy, if the diarrhea is persistent, if the diarrhea is unresponsive to empirical therapy, or if the infected person is immunocompromised Assays for the detection of C difficile toxins may also be indicated Routine microbiologic techniques oftentimes cannot detect many of the bacteria associated with persistent diarrhea The sensitivity of a single stool specimen for the detection of ova and parasites varies, depending on the parasite, but it rarely exceeds 80% The likelihood