Authorities recently requested residents of the city of Grimes, Iowa, to boil water that is intended for consumption after E. coli bacteria was detected in the main water supply.

Residents are being told to boil water for at least one minute and let it cool before using it for drinking, food preparation or other purposes. In addition, the authorities said residents also have the option of purchasing bottled water.

The authorities also warned that bottled or boiled water should only be used for drinking, washing dishes, preparing food, brushing teeth and making ice until further notice.

E.Coli and its Effects

E. coli, which is short for Escherichia coli, is a type of fecal coliform bacteria commonly found in the intestines of animals and humans. The presence of E. coli in water is a strong indication of recent sewage or animal waste contamination. There are many strains of E. coli, most of which are harmless, but some strains can cause illness.

During rainfalls, snow melts, or other types of precipitation, E. coli may be washed into creeks, rivers, streams, lakes, or groundwater. When these waters are used as sources of drinking water and the water is not treated or inadequately treated, E. coli may end up in drinking water.

These bacteria can cause illness, and serious illness among individuals with weakened immune systems. Infection often causes severe bloody diarrhea and abdominal cramps; sometimes the infection causes non-bloody diarrhea.

It should be noted that these symptoms are common to a variety of diseases, and may be caused by sources other than contaminated drinking water.

Particularly for young children, old people and people with compromised immune systems, the infection can also cause a complication called hemolytic uremic syndrome, in which the red blood cells are destroyed and the kidneys fail. About 2 percent to 7 percent of infections lead to this complication.

Hemolytic uremic syndrome is a life-threatening condition usually treated in an intensive care unit. Blood transfusions and kidney dialysis are often required. With intensive care, the death rate for hemolytic uremic syndrome is 3 percent to 5 percent.

Symptoms usually appear within 2 to 4 days, but can take up to 8 days. Most people recover without antibiotics or other specific treatment in 5-10 days.

There is no evidence that antibiotics improve the course of disease, and it is thought that treatment with some antibiotics may precipitate kidney complications. Antidiarrheal agents, such as loperamide (Imodium), should also be avoided.

Why Water Should be Boiled?

Boiling the water is the best way to ensure that it is free of illness-causing organisms. Bring water to a rolling boil for a minimum of one minute. When it cools, refrigerate the water in clean containers. (A pinch of salt per quart may improve the rather flat taste of boiled water).

Water is heated long enough to inactivate or kill micro-organisms that normally live in water at room temperature. Near sea level, a vigorous rolling boil for at least one minute is sufficient.

At high altitudes (greater than two kilometres or 5000 feet) three minutes is recommended. In areas where the water is "hard" (that is, containing significant dissolved calcium salts), boiling decomposes the bicarbonate ions, resulting in partial precipitation as calcium carbonate. This is the "fur" that builds up on kettle elements, etc., in hard water areas.

With the exception of calcium, boiling does not remove solutes of higher boiling point than water and in fact increases their concentration (due to some water being lost as vapour).

Boiling does not leave a residual disinfectant in the water. Therefore, water that has been boiled and then stored for any length of time may have acquired new pathogens.

In the event that boiling is not practical, the Public Water Systems may recommend an alternative supply known to be safe (e.g., bottled water). Buying bottled water may be a feasible alternative to boiling water. Bottled water operations are routinely inspected, and samples are periodically analyzed to ensure they meet health standards.

Boiling or treating contaminated drinking water with a disinfectant destroys all forms of E. coli, including O157:H7.

Infection Infection Water