As per definition, TD comprises the passage of three or more unformed stools within 24 hours and at least one of the following symptoms: fever, nausea and vomiting, abdominal pain or cramps, fecal urgency, tenesmus, mucoid stools or hematochezia [8]. Borborygmi and bloating are often reported. Despite the frequent elimination of watery stools, TD is rarely severe enough to cause dehydration. However, dehydration may be observed in hot climates and patients who don't take the appropriate measures to rehydrate.

Although disease severity varies largely, most cases are self-limiting within three to five days [4]. Though, in up to 3% of cases, symptoms may persist for more than a month. If differential diagnoses are ruled out, these patients may possibly be diagnosed with post-infectious irritable bowel syndrome [9].

The diagnosis of TD is based on anamnestic data and clinical symptoms. Since the majority of cases is self-limiting, additional diagnostic measures are rarely carried out. Nevertheless, it may be necessary to rule out more severe gastrointestinal disorders in cases of persistent diarrhea, hematochezia, or atypical complaints. Here, the following measures may be helpful:

• Bacteriological examination of stool samples, stool cultures. If anamnestic data and clinical presentation are consistent with TD, Enterobacteriaceae or Campylobacter spp. are most likely to account for the disease. Still, the patient's travel destination and medical history may indicate the need for an expansion of the diagnostic range.
• Microscopic examination of stool samples to reveal the presence of parasites.
• Persistent diarrhea is indicative of parasitic disease; fever, enhanced serum concentrations of C-reactive protein, and fecal leukocytes are more frequently associated with bacterial TD [10].
• Viruses may be detected in stool samples employing electron microscopy, antigen detection assays, or molecular biological techniques, among others.
• Testing of stool samples for Clostridium difficile toxin, particularly if the patient has recently taken broad-spectrum antibiotics.

Pathogens associated with TD comprise [6] [7]:

• Escherichia coli spp., especially enterotoxigenic strains, enteroaggregative strains
• Shigella spp.
• Salmonella spp.
• Campylobacter spp.
• Aeromonas spp.
• Plesiomonas spp.
• Vibrio spp.

• Entamoeba histiolytica
• Giardia lamblia
• Cryptosporidium spp.

• Norovirus
• Rotavirus
• Enteric adenovirus

Traveler's diarrhea (TD) is an unspecific term referring to distinct types of gastrointestinal infections that affect travelers and result in acute diarrhea, i.e., the passage of three or more unformed stools within a period of 24 hours [1]. It is the most common travel-related illness [2] and typically occurs within the first two weeks of traveling. Bacteria account for most cases of TD, but parasites and viruses may also trigger the disease. Pathogens are generally ingested with contaminated water or food, and first symptoms manifest within hours or few days after exposure. Patients are not necessarily aware of risky behavior since an infection may result from seemingly insignificant actions like cleaning one's teeth with a brush rinsed in non-potable water. Symptoms may persist for several days.

Oral rehydration is the mainstay of treatment and aims at compensating for water and electrolyte loss [3] [4]. Furthermore, self-treatment of TD often includes the use of antimotility drugs like loperamide, but patients should be advised on the potential risks of such therapy [4]. Antibiotics may be indicated in case the disease is caused by bacterial pathogens, but this therapeutic approach is associated with considerable disturbances of the normal intestinal flora. Thus, the use of antibiotics is not generally recommended unless a patient suffers from moderate to severe TD [5].

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