Water Protection Program fact sheet
Division of Environmental Quality Director: Kyra Moore

What is E. coli?

E. coli or Escherichia coli is a type of bacteria commonly found in the intestines and feces of healthy warm-blooded animals and humans. There are more than 100 different strains of E. coli, and most are harmless.

Why test for E. coli?

E. coli is a good indicator of the presence of fecal contamination and possible disease-causing bacteria or viruses in water. The test used for E. coli is far less expensive and more reliable than other bacterial tests. If high levels of E. coli are detected, the department can investigate the area further and work to correct any problems.

What is the state standard for E. coli?

The state water quality standard for water bodies with whole body contact for recreation is a geometric mean of 126 E. coli colonies per 100 milliliters of water during the April 1 through Oct. 31 recreation season. The geometric mean is a statistical method used to combine the data that reduces the effect of extremely high and low values that can bias the results.

Missouri’s standard is consistent with the U.S. Environmental Protection Agency’s recommendation for fresh-recreational waters, Ambient Water Quality Criteria for Bacteria - 1986, available on EPA’s website.

How is E. coli data reported?

There are several ways in which E. coli data is reported, but most refer to the same thing. These include colonies, cells, most probable number or colony-forming units per 100 milliliters. The latter two are frequently identified in notations as MPN or CFU, respectively.

Can fish from the lake be contaminated because of E-coli?

Because fish are not warm-blooded they do not carry E. coli internally; however, the water covering the fish could contain E. coli. Fish may also carry other parasites not associated with E. coli. Wash and cook fish thoroughly before eating, and wash your hands after handling fish and lake-water to reduce your risk. According to the Missouri Department of Health and Senior Services, the single most important way to prevent the spread of the disease is careful hand washing. For more information about proper food handling and preparation contact the Missouri Department of Health and Senior Services toll-free at 800-628-9891.

What are the symptoms associated with bacteria-caused illnesses?

Certain strains of E. coli, other bacteria, viruses, and parasites associated with fecal contamination can cause gastrointestinal illness. Symptoms can include, but are not limited to, diarrhea, stomach cramps and nausea. According to the Centers for Disease Control and Prevention, bloody diarrhea and stomach pain are the most common signs of E. coli O157:H7 sickness. For more information see the Questions & Answers: Sickness caused by E. coli on the CDC website.

What is E. coli O157:H7?

This is one strain of E. coli that can cause serious illness. It is usually associated with cattle, but has also been found in the intestines of deer, goats and sheep. The CDC states that most illnesses from this strain are associated with eating undercooked, contaminated beef, but can also be contracted after eating contaminated sprouts, vegetables, drinking unpasteurized milk or swimming in or drinking sewage-contaminated water.

According to the CDC, all persons who suddenly have diarrhea with blood should get their stool tested for E. coli O157:H7, and most people recover without antibiotics or other specific treatment within five to 10 days. For more information about the Lake of the Ozarks E. coli monitoring project, contact the Missouri Department of Natural Resources at 800-361-4827.

Other sources of information

Nothing in this document may be used to implement any enforcement action or levy any penalty unless promulgated by rule under chapter 536 or authorized by statute.

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