What is an E. coli infection?

E. coli is the name of a germ, or bacterium, that lives in the digestive tracts of humans and animals.

There are many types of E. coli, and most of them are harmless. But some can cause bloody diarrhea. These are called enterohemorrhagic E. coli (EHEC). One common type is called E. coli O157:H7. In some people, this type of E. coli may also cause severe anemia or kidney failure, which can lead to death.

Other strains of E. coli can cause urinary tract infections or other infections.

What causes an E. coli infection?

You get an E. coli infection by coming into contact with the feces, or stool, of humans or animals. This can happen when you drink water or eat food that has been contaminated by feces.

E. coli in food

E. coli can get into meat during processing. If the infected meat is not cooked to 160°F (71°C), the bacteria can survive and infect you when you eat the meat. This is the most common way people in the United States become infected with E. coli. Any food that has been in contact with raw meat can also become infected.

Other foods that can be infected with E. coli include:

• Raw milk or dairy products. Bacteria can spread from a cow's udders to its milk. Check the labels on dairy products to make sure they contain the word "pasteurized." This means the food has been heated to destroy bacteria.
• Raw fruits and vegetables, such as lettuce, alfalfa sprouts, or unpasteurized apple cider or other unpasteurized juices that have come in contact with infected animal feces.

E. coli in water

Human or animal feces infected with E. coli sometimes get into lakes, pools, and water supplies. People can become infected when a contaminated city or town water supply has not been properly treated with chlorine or when people accidentally swallow contaminated water while swimming in a lake, pool, or irrigation canal.

E. coli from person-to-person contact

The bacteria can also spread from one person to another, usually when an infected person does not wash his or her hands well after a bowel movement. E. coli can spread from an infected person's hands to other people or to objects.

What are the symptoms?

The main symptoms of an E. coli O157:H7 infection are:

• Bloody diarrhea.
• Stomach cramps.
• Nausea and vomiting.

Some people do not notice any symptoms. Children are more likely than adults to have symptoms. Symptoms usually start 3 or 4 days after you come in contact with the E. coli.

Most people get better in about a week. They often don't see a doctor and don't know that E. coli caused their problems.