Ground and surface water including streams, rivers, lakes and water used to irrigate crops, may be polluted by human and animal feces. Even though public water systems uses several methods like chlorine, ultraviolet light or ozone to kill E. coli, some outbreaks which contaminated municipal water supplies and also private wells have been reported.

Escherichia coli (E. coli.), is a member of a group of organisms known as coli-forms: common bacteria found in the digestive system of humans and animals. The presence of E. coli in water is a strong indication of recent sewage or animal waste contamination.  

The presence of E. coli is used as an indicator to examine the possible presence of other more harmful microbes. Runoff water from agricultural area, areas contaminated with pet manure, wastewater treatment plants, on-site septic systems and also wildlife that uses the water as their natural habitat, are possible sources of fecal contamination. If their concentration exceeds to a limit, it may cause these organisms to be washed into rivers, streams, lakes, or ground water. If this water is used for drinking without treatment, it may result in disease.

One of the 100 strains of E.coli; ( identified as E. coli O157:H7) is an emerging cause of waterborne illness. Although most strains of E. coli are harmless and live in the intestines of healthy humans and animals, the problem is with the powerful toxin that it produces which can cause severe illness.

E. coli O157:H7 was first recognized as a cause of illness from contaminated hamburgers during an outbreak in 1982. However, in 1999, people became sick after drinking contaminated water in Washington County, New York and swimming in contaminated water in Clark County, Washington.

Infection results in nausea, headaches, abdominal cramps with severe diarrhea at times accompanied with blood and sometimes not. Fever may not be present. In humans, particularly children under 5 years of age and the elderly, the infection can also cause a serious condition called hemolytic uremic syndrome (HUS), in which the red blood cells are destroyed and the kidneys fail. HUS is a life-threatening condition which often requires blood transfusions and kidney dialysis.

Symptoms usually appear within 2 to 4 days, maximum 8 days. Some patients may return to normal without treatment in 5-10 days. The treatment with antibiotics may harm kidney and does not show much improvement. It is good to avoid Anti-diarrheal drugs. Drink small sips of bottled water during the whole day to prevent dehydration.

Actions to be taken for protection from E. Coli infection:

1. Boil water for a minimum of 1 minute or use bottled water to drink.
2. Wash fruits and vegetables, in bottled water or water boiled for at least 1 minute.
3. Wash and rinse dishes with boiled or bottled water and dish soap.
4. Use a clean supply of water if possible for bathing.
5. Use bottled or boiled water for brushing the teeth.

Precautions:

1. Wherever surface water is being used, extra steps have to be taken to prevent bacterial contamination.
2. Public water systems using surface waters must be strictly disinfected.
3. People serving the public water system should visit the locations regularly.
4. Public water systems have to be tested for coli form bacteria.