The U.S. Centers for Disease Control and Prevention (CDC) is monitoring for a rare strain of toxin-producing Escherichia coli that, as of June 6, 2011, has been linked to the death of 18 people and to illness of more than 1,900 mostly in Germany. For the latest information on this outbreak, visit the Investigation Update page on the CDC web site.
E. coli are common bacteria normally found in the digestive tract of humans and animals. Most strains of E. coli don't cause problems, but some strains produce a toxin that can cause bloody diarrhea and other potentially serious illnesses. Many people are familiar with a particularly severe strain designated as O157:H7, a strain that makes a toxin similar to that made by another type of bacteria, shigella (termed shiga toxin-producing E. coli or STEC), which has been the culprit in several recent outbreaks of food-borne illness. Children and the elderly are usually the most severely affected by complications of STEC infections.
However, there are other less well-known strains of STEC, so-called "non-O157", which can cause similar health issues. The strain affecting those in Germany is called STEC O104:H4. The letters and numbers indicate the unique markers made by the bacterial strain.
Symptoms of STEC infection include severe stomach cramps, diarrhea that is often bloody, and vomiting. If there is fever, it is usually not very high. Most people get better within 5-7 days, but a very small number of people go on to develop hemolytic uremic syndrome (HUS). The symptoms of HUS include decreased frequency of urination (evidence of kidney damage or uremia), feeling very tired, and losing the normal pink color to skin and membranes due to anemia caused by breakdown of the red blood cells (hemolysis). While to date the outbreak seems confined to Europe, one confirmed and three suspected cases of STEC O104:H4 infections have been identified in the U.S. among persons who recently traveled to Hamburg, Germany, where they most likely contracted the infection.
Laboratories are advised to perform testing for STEC on all stool samples submitted for bacterial pathogens. Any suspected STEC detected need to be sent to public health labs for the strain to be identified as soon as possible. This requires specialized molecular tests that are performed to characterize/type the unique strain of STEC causing the infection. Once the strain of E. coli is characterized as the outbreak strain, the public health official who tracks and studies outbreaks (epidemiologist) can investigate potential sources of exposure to STEC and employ prevention measures.
While transmission from person to person is infrequent, the most common means is by soiled hands. Anyone who has diarrhea should wash their hands thoroughly after using the bathroom and avoid preparing food for others until they recover. The source and means of transmission of the STEC that is affecting so many in Germany is currently under investigation. Public health officials there suspect the source is contaminated raw vegetables from northern Germany, but this has not been confirmed.
For people planning to travel, it is advisable to review health risks for your destination at the Travelers' Health page of the CDC web site well in advance of your departure. For the latest information relevant to Germany, see the CDC’s Outbreak Notice.
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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.
(June 7, 2011) Centers for Disease Control and Prevention. Investigation Update: Outbreak of Shiga toxin-producing E. coli O104 (STEC O104:H4) Infections Associated with Travel to Germany. Available online at http://www.cdc.gov/ecoli/2011/ecoliO104/index.html through http://www.cdc.gov. Accessed June 8, 2011.
(June 8, 2011) World Health Organization. EHEC Outbreak, Update 11. Available online at http://www.euro.who.int/en/what-we-do/health-topics/emergencies/international-health-regulations/news/news/2011/06/ehec-outbreak-update-11 through http://www.euro.who.int. Accessed June 8, 2011.
(©2010) Association of Public Health Laboratories. E. coli and STEC. Available online at http://www.aphl.org/aphlprograms/food/microbiology/Pages/ecoli.aspx through http://www.aphl.org. Accessed June 2011.
(July 2, 2009) National Institute of Allergy and Infectious Diseases. E. coli. Available online at http://www.niaid.nih.gov/topics/ecoli/Understanding/Pages/overview.aspx through http://www.niaid.nih.gov. Accessed June 2011.