The Public Health Agency of Canada is warning the public about an outbreak of a potentially deadly form of E. coli after at least 24 people became infected and five of them ended up being hospitalized.

The 24 cases of Escherichia coli O157 occurred between July 12 and Aug. 8, with the “peak of illnesses” reported between July 25 and Aug. 1, according a statement from PHAC. The source of the illnesses has not yet been identified and the investigation is ongoing.

Most of those who became ill (63 per cent) were male, had an average age of 24, and were located in the following four provinces:

  • Alberta (one case)
  • Nova Scotia (two cases)
  • Ontario (seven cases)
  • Quebec (14 cases)

E. coli O157 can lead to severe stomach cramps, watery or bloody diarrhea, vomiting, nausea, headache and slight fever. Symptoms usually occur within 10 days of coming into contact with the bacteria.

“While most will recover completely, others may suffer permanent health effects, like kidney damage, and some may die,” according to PHAC.

The disease is most serious in pregnant women, those with compromised immune systems, young children and older adults, PHAC added.

E. coli O157 killed seven people and sickened more than 2,300 in 2000 in Walkerton, Ont., where the drinking water supply was tainted.

In March, a cluster of a dozen E. coli infections across Canada were thought to have been caused by contaminated leafy green vegetables, PHAC said at the time.

The primary sources of E. coli are raw or undercooked meat or dairy products, or fruits and vegetables that have come in contact with feces from infected animals.

The PHAC offers the following tips to reduce the risk of infection:

  • Always ensure foods are thoroughly cooked to a safe internal temperature.
  • Wash fresh fruits and vegetables before eating them, clean counters and cutting boards and wash your hands regularly.
  • Bacteria can grow in the danger zone between 4 °C and 60 °C (40 °F to 140 °F). Keep cold foods cold at or below 4 °C (40 °F) and keep hot foods hot at or above 60 °C (140 °F).
  • Keep refrigerators clean and at a temperature below 4 °C (40 °F). Install a thermometer in your fridge to be sure.
  • Place raw meat, poultry and seafood in containers on the bottom shelf of the refrigerator. Use containers that are large enough to prevent raw juices from dripping onto other food or touching other food.
  • Keep raw food away from other food while shopping, storing, preparing and serving foods.
  • Read labels and follow cooking and storage instructions for all food. When buying food, make sure to check the "best before" date, and if the product has expired, let the store know.
  • Use warm soapy water to clean knives, cutting boards, utensils, your hands and any surfaces that have come in contact with food, especially meat and fish.
  • Refrigerate or freeze perishable food within two hours of cooking.
  • Freeze or consume leftovers within four days of cooking. Always reheat leftovers until steaming hot before eating.