Listeriosis Outbreak In Canada

A rash of Listeriosis cases in Canada has given rise to more public awareness of this illness. The recent presentation became manifest as a food borne illness, has been traced to one food processing company, and the facility is undergoing a thorough clean-up. Even though Listeriosis can present as a food borne illness, it is quite different from the contamination of foods with E. coli (“hamburger disease”) or food borne illness to salmonella contamination. The onset of illness in hamburger disease occurs rather quickly after the food has been ingested and can lead to a serious illness with kidney failure. Listeriosis, which is caused by the bacterium Listeria monocytogenes has a much longer incubation time, in some cases up to 70 days, and it can take much longer till it is detected. It can present like a febrile gastroenteritis (a stomach flu accompanied by a fever) in people who have a weakened immune system. A less common disease picture shows symptoms that look like influenza, but sometimes there can be shock and malfunction of the kidneys. In early pregnancy the infection with Listeriosis can lead to miscarriage, and late in pregnancy the result may either be stillbirth or sepsis in the newborn.

Listeriosis Outbreak In Canada

Listeriosis Outbreak In Canada

Even if the disease in the pregnant patient is mild, it will be almost always fatal for the child in the womb. If Listeria infection is suspected in the case of gastroenteritis, the laboratory should be notified, so the stool or blood specimens are kept and especially examined for Listeria. Foods that carried the bacterium and caused the illness were sandwich meats and ready made sandwiches. Consumers should inform themselves carefully, which food products were affected by recalls and also check packages for expiry dates.

More information on food safety:

Reference: CBC News and Cohen & Powderly: Infectious Diseases, 2nd ed. 2004 Mosby

Last edited November 5, 2014


Hamburger Disease – A Sizzling Problem

One of the many strains of the bacterium E. coli (type 0157:H7) became famous after a 1982 outbreak of bloody diarrhea across the U.S. The infection could be traced back to contaminated hamburgers sold by a fast food chain. Canada also had some smaller food-related outbreaks, but a large disastrous outbreak occurred in Walkerton, Ontario. In this case the culprit was cow manure that was washed into surface water. The water was not optimally treated at the local water works and then consumed by the local community. It is important to know, that infection with E. coli bacteria can be spread in various ways as shown in this table.

Hamburger Disease – A Sizzling Problem

Hamburger Disease – A Sizzling Problem

The symptoms of infection usually present themselves after an incubation period of 3 to 8 days in the form of abdominal cramps, diarrhea that can also be bloody, and vomiting. Unfortunately, a more severe form can occur in 2 to 10% of patients due to the toxic substances of the bacterium. The dreaded form of “hamburger disease”, is medically known as hemolytic uremic syndrome, and children are at the highest risk, along with older adults or those with immune suppression (AIDS patients, cancer patients). The disease is life threatening, requires blood transfusions, dialysis and life-support therapy in an intensive-care unit setting.

Hamburger disease is caused by:
Contact with livestock (or feces)
Human-to-human contact
Consumption of non-chlorinated contaminated water
Consumption of insufficiently cooked ground beef, salami, unpasteurized milk, even vegetables like
lettuce or alfalfa sprouts that have not been washed.

Prevention is of utmost importance, and fortunately a lot of it is common sense about food safety and safe food-handling practices:

Hints to prevent Hamburger disease:
Wash your hands after handling animal and livestock after using the washroom and after changing diapers.
Wash your hands before and after preparing or eating food and handling raw meat.
Never put raw meat in contact with cooked meat and disinfect areas of meat preparation like
counters or cutting boards.
Make sure all the pink color is gone from cooked meats, and juices after cooking should never
be bloody!
Drink only pasteurized milk, fruit juices or ciders.
Never drink water from untreated sources (creeks, ponds).
Practice strict hand hygiene when dealing with persons who have diarrhea, especially when changing diapers of children with diarrhea.

Besides prevention, vigilance is important: if any case of E. coli infection has been found, the local health units have to be notified, so the source of infection can be found and further spread can be prevented.

More info on food safety:

Reference: The Canadian Journal of Continuing Medical Education, September 2004, Vol.16, Nr.9, pg.49.

Last edited January 4, 2015