Travelers' Diarrhea

  • Medical Author:
    John P. Cunha, DO, FACOEP

    John P. Cunha, DO, is a U.S. board-certified Emergency Medicine Physician. Dr. Cunha's educational background includes a BS in Biology from Rutgers, the State University of New Jersey, and a DO from the Kansas City University of Medicine and Biosciences in Kansas City, MO. He completed residency training in Emergency Medicine at Newark Beth Israel Medical Center in Newark, New Jersey.

  • Medical Editor: William C. Shiel Jr., MD, FACP, FACR
    William C. Shiel Jr., MD, FACP, FACR

    William C. Shiel Jr., MD, FACP, FACR

    Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

  • Medical Editor: Charles Patrick Davis, MD, PhD
    Charles Patrick Davis, MD, PhD

    Charles Patrick Davis, MD, PhD

    Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

Quick GuideTravel Health: Vaccines & Preventing Diseases Abroad

Travel Health: Vaccines & Preventing Diseases Abroad

What causes travelers' diarrhea?

Travelers' diarrhea usually is contracted by the ingestion of contaminated food or water. Contrary to common belief, food - not water - is the primary cause. The CDC estimates up to 80% of cases of travelers' diarrhea are caused by bacteria. The most common bacterium that causes travelers' diarrhea is enterotoxigenic E. coli, one of six classes of enterovirulent E. coli.

Most E. coli are harmless. However, there are six unique classes of E. coli that can cause inflammation of the stomach and bowels (gastroenteritis) and are termed enterovirulent. They are virulent (extremely noxious) to the intestine (or, in Greek, the enteron).

Collectively, these six classes of enterovirulent E. coli are referred to as the EEC group (enterovirulent E. coli). Each class of EEC is distinct and different from the others.

  • Enteroinvasive E. coli (EIEC) invades (passes into) the intestinal wall to produce severe diarrhea.
  • Enterohemorrhagic E. coli (EHEC) is a type of EHEC, E.coli 0157:H7 that can cause bloody diarrhea and the hemolytic uremic syndrome (anemia and kidney failure).
  • Enterotoxigenic E. coli (ETEC) is the one that causes most of travelers' diarrhea, and produces a toxin that acts on the intestinal lining.
  • Enteropathogenic E. coli (EPEC) can cause diarrhea outbreaks in newborn nurseries.
  • Enteroinvasive E. coli (EIEC) invade the epithelial cells causing diarrhea with mucus and blood.
  • Enteroaggregative E. coli (EAggEC) can cause acute and chronic (long lasting) diarrhea in children.

Other bacterial species implicated in travelers' diarrhea include Campylobacter jejuni, Shigella, and Salmonella. Viruses (including Rotavirus, Norwalk virus and other enteric viruses) less commonly are causes of travelers' diarrhea. Parasitic infections are an uncommon cause with the exception of Giardia lamblia, which should be suspected in individuals traveling to Russia or to mountainous regions of the Northern Hemisphere. Cryptosporidum, another parasite, also has been implicated as a common cause of diarrhea in visitors to St. Petersburg, Russia and elsewhere.

Medically Reviewed by a Doctor on 3/16/2016

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