الثلاثاء، 7 يونيو 2011

E. Coli Diarrhea - Traveler's Diarrhea


Overview, Causes, & Risk Factors

Traveler's diarrhea refers to diarrheal disease caused by toxins produced by a number of different strains of Escherichia coli and other bacteria.
What is going on in the body?
Traveler's diarrhea begins when a person swallows E. coli or other bacteria. This happens through close contact with feces from an infected person or animal. It can also come from ingesting food or water that has been contaminated with the bacteria. There have been numerous outbreaks of E. coli illness linked to unpasteurized contaminated cow's milk or undercooked hamburger meat. The disease can also pass from person to person, especially between children still in diapers.
What are the causes and risks of the disease?
Traveler's diarrhea is caused by certain bacteria, such as E. coli. Travelers generally come into contact with these bacteria by ingesting contaminated food or water. Travelers to the following countries are at particular risk:
  • Central America, including the islands of the West Indies

  • the developing countries of Africa

  • the Middle East


    • Any raw food can be a source of these bacteria. However, the following foods and beverages pose the highest risk:
  • certain fish, particularly tropical fish

  • raw meat

  • salads

  • shellfish

  • uncooked vegetables and fruit

  • unpasteurized fruit juice

  • unpasteurized milk and milk products

  • untreated water


    • Traveler's diarrhea is more common in younger people but can occur at any age. People with immunodeficiency disorders, such as HIV, are at higher risk.

    Symptoms & Signs

    What are the signs and symptoms of the disease?
    The type of bacteria causing the infection determines the symptoms of the disease. Symptoms of traveler's diarrhea may include:
  • abdominal cramping

  • diarrhea with or without blood

  • fever

  • malaise, or a vague feeling of illness

  • nausea

    • Diagnosis & Tests

    How is the disease diagnosed?
    Diagnosis of traveler's diarrhea begins with a medical history and physical exam. The bacteria can be cultured from an infected person's stool. A special test can be done to detect E.coli O157:H7.

    Prevention & Expectations

    What can be done to prevent the disease?
    The best way to prevent traveler's diarrhea is to pay very close attention to the foods and beverages ingested. Here are some guidelines to follow.
  • Avoid contaminated water and ice made from that water.

  • Avoid food sold by street vendors.

  • Avoid unpasteurized milk and juice.

  • Breast-feed infants or provide formula that has been mixed with boiled water.

  • Cook meat, poultry, and seafood thoroughly, and eat it while it is still hot.

  • Drink beverages, such as coffee and tea, made from boiled water.

  • Drink canned or bottled carbonated water and soft drinks.

  • Dry wet cans or bottles before opening them, and wipe surfaces that will touch the mouth.

  • If no safe water source is available, treat contaminated water by boiling it or adding disinfectants such as iodine or chlorine.

  • Wash fruits and vegetables thoroughly in uncontaminated water and peel them yourself.


    • Traveler's diarrhea can be prevented by taking medicines while in areas where the risk is high. Such medicines include:
  • bismuth compounds

  • norfloxacin, ciprofloxacin, or ofloxacin

  • trimethoprim-sulfamethoxazole

  • doxycycline


    • What are the long-term effects of the disease?
    Certain strains of E. coli, like the O157:H7 strain, cause hemorrhagic colitis. This illness causes inflammation of the large intestine and bloody diarrhea in both adults and children. This strain can also cause a complication called hemolytic uremia syndrome (HUS). This disorder causes red blood cell destruction, a low platelet count, and loss of kidney function. HUS can range from a mild illness to a severe condition resulting in permanent kidney damage. HUS usually follows a case of bloody diarrhea.
    What are the risks to others?
    A person who has been infected with E.coli and other bacteria can potentially pass them to others. There is a particular danger if the infected person does not wash his or her hands thoroughly.

    Treatment & Monitoring

    What are the treatments for the disease?
    Oral fluids, including rehydration solutions, are important to prevent dehydration. In most cases, antibiotics are not needed. However, they may be useful in the treatment of very young infants or with certain types of E.coli. They may also be recommended for immunocompromised individuals, or those with weak immune systems.
    Medicines to control diarrhea should not be administered to children with diarrhea, especially if the diarrhea is bloody. They could cause the diarrhea to last longer or to make it worse.
    Traveler's diarrhea may be treated with the same drugs used to prevent it. In addition to the medicines listed earlier, loperamide may reduce the diarrhea.
    What are the side effects of the treatments?
    The medicines used to treat traveler's diarrhea can cause allergic reactions. They may also make the person more sensitive to sunlight and increase the risk of sunburn. Drugs for diarrhea may also cause nausea.
    What happens after treatment for the disease?
    Traveler's diarrhea usually goes away, with or without treatment, within 1 week. Hemorrhagic colitis is more serious and lasts longer, especially if HUS develops. Kidney failure may develop in as many as 50% of children. Severe kidney failure can lead to high blood pressure. HUS may recur with repeated infections but not usually after the first year. Most children with HUS have a nearly complete recovery. Up to 1/3, though, have lasting evidence of some kidney damage.
    How is the disease monitored?
    Persons with severe diarrhea or HUS need to be monitored closely to be sure their blood chemicals remain in balance. Elderly people who are receiving fluid replacement are watched closely for congestive heart failure. If kidney failure develops, fluid intake and output must be measured carefully to keep them in balance. Tests are sometimes used to be sure the E. coli toxin is no longer in the stool. Any new or worsening symptoms should be reported to the healthcare provider.

    Attribution

    Author:Danielle Zerr, MD
    Date Written:
    Editor:Crist, Gayle P., MS, BA
    Edit Date:09/30/01
    Reviewer:Eileen McLaughlin, RN, BSN
    Date Reviewed:08/30/01
    Sources
    Scientific American Medicine 10(VII):6-7, 2000
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