E. coli (pronounced "ee koh-lie") is a common species of bacteria. The name, E. coli, is an abbreviation. It stands for the bacteria's Latin scientific name, Escherichia coli (pronounced "eh-sher-rish-ee-uh koh-lie"). It belongs to a group of bacteria that specialize in living in the intestines of animals.

Bacteria are everywhere. We unknowingly consume bacteria when we eat or drink, or put our hands in our mouths. This is how bacteria get into our intestines. We get rid of some of the bacteria from our intestines every time we defecate. In fact, as much as 25% (1/4) of your feces is bacteria (the rest is mostly undigested food).

E. coli is a species of bacteria that includes many different strains (types of individuals which are slightly different from one another). Most E. coli strains are beneficial to humans. They live in our intestines and produce important vitamins, such as vitamin K and B-complex vitamins, which we absorb. You should rejoice at the billions of bacteria living in your intestines!

There is one strain of E. coli, however, which is very harmful to humans: strain O157:H7. When humans consume this strain they can get very sick, and even die. Symptoms include diarrhea (sometimes with blood in the feces) and dehydration. Some people also develop kidney problems and intestinal bleeding.

Your water supply, and many streams and rivers, are regularly tested for E. coli. The presence of E. coli in drinking water supplies is of important concern for two reasons. First, the presence of E. coli strongly indicates that human and other animal waste has recently contaminated the water. Second, it is possible that the contamination includes the rare E. coli strain O157:H7.

Remember, the best way to keep water clean is to prevent water contamination in the first place. We all must practice good sanitation at home or while camping, and be careful that proper waste disposal is being practiced by people who raise farm animals or work in industry.