Travel to Developing Countries - Traveler's Diarrhea

Traveler's Diarrhea

Traveler's diarrhea (TD) is the most common health problem a traveler encounters. It is almost always caused by ingesting certain organisms in contaminated food or water. Diarrhea can also be caused -- particularly in children -- by anxiety, stress, allergies, fatigue, and dietary changes.

Symptoms and Course

Diarrhea frequently occurs within the first week of travel, but may develop at any point, even after returning home. Traveler's diarrhea causes four or five loose or watery stools per day. Vomiting may also occur. It usually lasts 3 or 4 days, but about 14% of cases last longer. In rare cases, the diarrhea lasts more than 3 months. When TD lasts a long time, it can cause post-infectious irritable bowel syndrome. Traveler's diarrhea is rarely life threatening, although it can be severely debilitating, especially in children. Weakness, reduced urine output, lightheadedness, and mental changes require immediate medical attention, especially in children. Life-threatening symptoms include reduced levels of consciousness, seizures, and coma.

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Risk by Country

Traveler's diarrhea typically affects 40 - 60% of people from industrialized nations who visit developing countries:

• High-risk destinations include most of the developing countries of Latin America, Africa, the Middle East, and Asia. The risk varies widely, however.
• Intermediate-risk destinations include most Southern European countries and a few Caribbean islands.
• Low-risk destinations include Canada, Northern Europe, Australia, New Zealand, the United States, and some Caribbean islands.

Infectious Causes

Several infectious organisms, including bacteria, parasites, and viruses, can cause diarrhea in travelers. These organisms are most often transmitted through contaminated food and water. Bacteria and viruses cause diarrhea within a few hours and up to 3 days, while diarrhea from parasites can occur 7 - 14 days after exposure. In about 10 - 50% of cases, the cause is unknown.

• The most common bacterial cause of traveler's diarrhea is Escherichia coli (E. coli). Certain strains of this organism are toxic to the intestines. E. coli accounts for 20 - 50% of TD cases. It is found in soil, water, and milk and occurs in major regions in the world, with the highest rates in Latin America and the lowest in Asia. Diarrhea caused by E.coli is generally explosive, non-bloody, and accompanied by nausea, vomiting, cramps, and fever.
• Noroviruses, also called Norwalk-like viruses, are an increasingly common cause of traveler's diarrhea in countries such as Mexico and Guatemala, and on cruise ships. Recent studies of travel in these destinations rank noroviruses second to E. coli for causing diarrhea.
• Shigella is the bacterial cause of dysentery, affecting 15% of travelers. It is common in countries experiencing natural disasters, socioeconomic upheaval, and during times when clean food and water are hard to find. Shigella causes bloody, mucus-laden diarrhea along with fever, cramps, and exhaustion.
• Campylobacter is a very common food- and water-borne bacterial cause of diarrhea in certain regions, notably Thailand and Morocco, during the winter.
• Giardia is a parasite found in contaminated water in every country in the world. It can cause chronic diarrhea lasting for several weeks, in addition to vague pain, weight loss, excessive burping, bloating, and fatigue.
• Entamoeba histolytica is a parasite prevalent Mexico, India, Africa, and Central and South America. It produces small stools that contain blood and mucus. If the condition becomes chronic, it can resemble inflammatory bowel disease (IBD). It is important to distinguish the two, since corticosteroids used to treat IBD can have dangerous effects in people carrying the parasite.
• Additional common culprits are the bacteria Salmonella, parasites (Cryptosporidiosis, Cyclospora, and Microsporidia), and rotavirus (usually in Latin America).