E. coli 0157:H7 infection:  Fact Sheet

What is E. coli 0157:H7?

E. coli is short for Escherichia coli, a (bacteria) germ commonly found in the intestines of humans and mammals.  Some types of E. coli can cause disease.  One of these is E. coli O157:H7, a toxin-producing strain better known as the cause of hamburger disease.  It is the same bacteria which has caused illness and deaths in the recent outbreak in Walkerton, Ontario.

What are the symptoms of E. coli 0157:H7 infection?

Symptoms can start two to ten days after contact with the germ.  The first sign is usually abdominal cramps that start suddenly.  After a few hours, watery diarrhea starts. T he diarrhea may cause your body to lose fluids and electrolytes (dehydration).  This makes you feel sick and tired. You may have a mild fever.  You may also have nausea or vomiting. Within a day or two, the diarrhea may become bloody.

Are there complications from E. coli 0157:H7 infection?

Dehydration may occur if diarrhea fluid loss exceeds intake of fluids.  The most serious complication is called hemolytic uremic syndrome (HUS).  People with this problem get hemolytic anemia (loss of red blood cells), thrombocytopenia (low platelets) and kidney failure.  HUS is more common in children.  This problem usually starts about 5 to 10 days after the diarrhea starts.  Hospital treatment is required and may include dialysis (artificial kidney machine).  Death occurs in a small percentage of cases, more likely among the very young and the very old.

How is E. coli 0157:H7 infection diagnosed?

The diagnosis is confirmed by finding this type of E. coli in the stool.  A sample of stool must be submitted to a lab which uses special techniques to grow and identify the bacterium and its toxin.

How is the infection treated?

There is no special initial treatment, except drinking enough clear fluids and watching for complications.  Don't take medicine to stop diarrhea unless your doctor tells you to, as this could interfere with your body’s efforts to clear the infection and the toxin. Antibiotics should not be taken.  They are not effective and increase the risk of complications.  If you are dehydrated, you will need to be assessed for the need for intravenous fluids.  In severe cases, intensive hospital care and support - including dialysis - may be required.  An experimental treatment, which binds toxin, has been offered on compassionate grounds.

What is the source of an E. coli infection?

You can catch E. coli infection by any one of the following:

• Eating undercooked ground beef (the inside is pink)
• Eating food contaminated during preparation by bacteria from uncooked meats
• Drinking contaminated (impure) water
• Drinking unpasteurized (raw) milk
• Working with cattle or raw meat products
• From another person infected with E. coli.
• Contact with soils contaminated with sewage or manure

Healthy beef and dairy cattle may carry the E. coli 0157:H7 germ in their intestines. Their manure may contaminate food or water sources.  Their meat can get contaminated with the germ during the slaughtering process.  When beef is ground up, the E. coli 0157:H7 germs get mixed throughout the meat.

The most common way to get this infection is by eating undercooked hamburgers. You can be infected with the E. coli 0157:H7 germ if you don't use a high temperature to cook your beef, or if you don't cook it long enough.

The germ can also be passed from person to person in day care centres and nursing homes.  If you have this infection - and don't wash your hands well with soap after going to the bathroom - you can give the germ to other people when you touch them or other things, especially food.  E. coli 0157:H7 is most contagious during the time that diarrhea is present.

How can I prevent E. coli infection?

You can help prevent this infection by taking the following precautions:

• Wash your hands often and carefully with soap and hot water, especially after using the bathroom and before and after cooking or handling food.
• Don't put cooked hamburgers or other food on a plate or surface that had raw ground beef or other uncooked meat on it before.
• Keep raw meat and poultry separate from other foods. Use hot water and soap to wash cutting boards and dishes if raw meat and poultry have touched them.
• Cook ground beef until you see no pink anywhere; do not eat hamburgers which are undercooked.
• Don't drink raw milk.
• Keep food refrigerated or frozen.
• Keep hot food hot and cold food cold.
• Refrigerate leftovers right away or throw them away.
• Keep wells in good repair and free from nearby sources of sewage contamination.
• Test samples of water from private wells and water sources regularly for bacterial or sewage contamination.
• Prevent children from playing in areas which may be contaminated by cattle or other sewage.
• Avoid close contact with people known to be infected.

What should I do if I think that a family member has an E. coli infection?

If you have some or all of these symptoms - watery diarrhea, cramps, fever, nausea or vomiting - contact your doctor. I f you have bloody diarrhea, seek medical care as soon as possible.  Your doctor can arrange a test to find out if you have E. coli in your intestines and recommend treatment.  Remember there are other causes of these symptoms besides E. coli.  Pay special attention to personal hygiene (especially careful and frequent handwashing) to prevent spreading the infection to others.

Infected children shouldn't go to a day care centre until their diarrhea is cleared up and tests show that they are no longer infected.  Older children and adults may return to school or work when their diarrhea has stopped.  Older people in nursing homes should be isolated until they are no longer infectious.  Good hygiene should be reinforced.

If you have any questions, contact your local public health office or Health Links at 1-888-315-9257 or 204-788-8200.