Travel to the developing countries is a marvelous way to experience the diversity of humankind. Visiting historic treasures, observing the wonders of nature, and experiencing the fascinations of different cultures and the taste of new cuisine are the inherent values of this type of travel. Unfortunately, along with the benefits of travel come the possibilities of unusual "tropical" illness, the most frequent of which is travelers diarrhea. Although called by many colorful names (Montezuma's revenge, Delhi belly, Aztec two-step) according to location, they all represent the same illness. This type of illness was first recognized by Kean and Waters in the 1950s as a distinct entity in which large numbers of vacationers and students from the developed world began to visit the developing world, where water and sanitation were substandard. When it was first described it was attributed to changes in composition of food and water and to jet lag, and was thought generally not to be infectious or viral because bacteriological cultures were not helpful in defining an etiologic agent. Infectious Etiology When Read more [...]

ETEC Heading the list in nearly all studies is ETEC. These organisms are the most common bacterial cause of diarrhea in children living in the developing world, and they are also the most commonly seen in travelers. These organisms produce either one or both of two enterotoxins: a heat labile enterotoxin (LT), a large molecule that is very closely related to cholera toxin, and a heat stable enterotoxin that is a small molecular weight polypeptide. They also possess colonization factors (CFAs), proteins that facilitate their binding to the small intestinal mucosa. Both LT and CFAs are anti-genic, so that infection results in some degree of immunity. Enteroaggrative E. coli A more recently discovered type of E. coli, called enteroaggrative E. coli, has also been found to be common in travelers' diarrhea. This organism was first recognized by its ability to aggregate when placed in Vero cell cultures. The mechanisms of virulence are not as well described as they are for ETEC, but they are also known to be common causes of diarrhea in children living in the developing world. TABLE. Estimates of Read more [...]

The two goals of treatment are to prevent dehydration and to eliminate the organisms causing the infection. Dehydration Dehydration can be prevented by the intake of adequate fluids and electrolytes during the time of liquid diarrhea. In mild cases, increasing normal fluid intake (juices, soups, etc) is adequate. For more severe cases, an oral rehydration solution (ORS), which was developed to treat severe diarrhea in children, particularly in the developing world, should be taken. An ORS can be used for any type of diarrhea causing significant fluid loss. This solution contains sodium, potassium, chloride, citrate, and a carbohydrate (glucose, sucrose, or rice powder). It is available in packets (Ceralyte, Cera Products, Jessup, Maryland) that can be taken with the traveler to use as indicated. In the rare event of a cholera-like disease, where very large quantities of a watery stool are passed, IV therapy (Ringer's lactate) may be necessary. This requires a visit to a health facility, but can hopefully be avoided with the use of ORSs begun early in the course of the disease. Antimicrobials Antimicrobials Read more [...]

Infectious diarrhea is a problem of global proportions, causing 4 to 6 million deaths each year. In North American adults, approximately 200 million cases of diarrhea occur annually, or 1.2 to 1.9 cases of diarrhea per adult. The etiologies and the spectrum of illness from acute infectious diarrhea are broad. This chapter will focus on therapies for the most common causes of infectious diarrhea in adults. Diagnostic Approach Acute infectious diarrhea is caused by a remarkable variety of microorganisms. The clinical presentation, however, is often nonspecific. Historical features, such as travel, ingestion of seafood, similar illnesses among close contacts, antibiotic use, and comorbidities, such as human immunodeficiency virus infection, help guide the differential diagnosis. The physical examination permits an assessment of the degree of dehydration and malnutrition. The role of the microbiology laboratory in the diagnosis of gastroenteritis is critical. Notably, the routine "stool work-up" (bacterial cultures and examination for ova and parasites) fails to diagnose a large proportion of gastroenteritis Read more [...]

Rehydration The restoration and maintenance of adequate hydration is the most important component of the treatment of acute infectious diarrhea. Rehydration is particularly important in the elderly, pediatric, or immunocompromised patient. In otherwise healthy patients with mild to moderate diarrhea, increasing intake of most fluids is usually adequate to replace fluid losses. In moderate to severe diarrhea, however, fluids with appropriate electrolyte concentrations are needed. Water, juices, and sports drinks will not adequately replace electrolyte losses. For dehydrating diarrhea, aggressive oral rehydration with electrolyte solutions or intravenous (IV) fluids is required. The formulation of "oral rehydration solutions" (ORS), as determined by the World Health Organization (WHO), includes precise concentrations of sodium, potassium, chloride, citrate/bicarbonate, and glucose to replace fluid and electrolyte losses from diarrhea and avoid IV fluid administration. Commercial pediatric formulations are readily available (eg,Pedialyte).Ahome ORS recipe, based on WHO formulations, is available Read more [...]

Bacterial Pathogens Salmonella Nontyphoidal species of Salmonella cause approximately 1.4 million cases of gastroenteritis and diarrhea annually. Contaminated meat, poultry, and eggs are common sources of infection, although bean sprouts, tomatoes, and orange juice have also been linked to outbreaks of salmonellosis. Other than diarrhea, clinical features may include abdominal pain, fever, and chills. Grossly bloody diarrhea is uncommon. Patients may carry Salmonella in their stools for weeks after symptoms resolve and 0.2 to 0.6% of patients may carry Salmonella over 1 year (long term carriers). The majority of cases in healthy adults are self-limited and do not require antibiotics. However, Salmonella can invade vascular sites and cause systemic toxicity in compromised hosts. Therapy (see Table Therapy of Infectious Diarrhea) is indicated for patients with systemic toxicity or bacteremia, aged under 6 months or over 50 years, and in patients With prosthetic joints, heart valves or vascular grafts, severe atherosclerosis, malignancy, immunodeficiency virus acquired immunodeficiency syndrome (AIDS), Read more [...]