Sunday, February, 12, 2012

Travel to Developing Countries - Traveler's Diarrhea

Table of Contents

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).

Water Precautions

Drinking contaminated water is the most common cause of acquiring traveler's diarrhea. The following methods or products help reduce exposure to contaminated water.

  • Boiling water is the best method for eliminating infectious organisms. There is some debate about how long to boil, but bringing the water to a good boil for at least 1 minute generally renders it safe to drink. Travelers might consider buying an electric heating coil to boil and purify tap water. (A plug adapter or voltage converter may be needed).
  • Carbonated bottled water may be used for brushing teeth and drinking. Carbonation increases the acid in the water and kills bacteria. Plain bottled water may not be safe, since it can be taken from contaminated sources. Even ice cubes can carry infection.
  • Iodine tablets such as Polar Pure, Globaline, or Potable-Aqua purify water. Water may be purified by adding one iodine tablet to a quart of water 30 minutes before drinking it. Adding 50 mg of vitamin C will eliminate the iodine taste and color. NOTE: Purifying is not effective against parasites such as Cyclospora and Cryptosporidium.
  • Small portable water filters remove parasites and clear murky water without leaving a chemical taste. They are particularly beneficial for pregnant women and people who cannot take iodine. NOTE: Filtering does not prevent viruses from passing through. When purchasing a filter, the phrase "EPA Registration" should be printed on the label, indicating that the U.S. Environmental Protection Agency has guaranteed its effectiveness.
  • Newer portable water purification systems, such as SteriPEN, use ultraviolet light to disinfect water. These handheld devices can destroy bacteria, viruses, and protozoa, such as Giardia and cryptosporidium.
  • In all cases, do not swim in water that may be contaminated or may contain parasites.

Food Precautions

Some important tips:

Review Date: 01/30/2011
Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org)