(CANADA) – The Public Health Agency of Canada is collaborating with provincial public health partners, the Canadian Food Inspection Agency, Health Canada, as well as the United States Centers for Disease Control and Prevention (U.S. CDC) and the United States Food and Drug Administration (U.S. FDA), to investigate an outbreak of E. coli infections in Ontario, Quebec, New Brunswick, and several U.S. states.
In Canada, based on the investigation findings to date, exposure to romaine lettuce has been identified as a source of the outbreak, but the cause of contamination has not been identified. Laboratory analysis indicates that the illnesses reported in this outbreak are genetically related to illnesses reported in a previous E. coli outbreak from December 2017 that affected consumers in both Canada and the U.S.
This tells us that the same strain of E. coli is causing illness in Canada and the US as was seen in 2017 and it suggests there may be a reoccurring source of contamination. Investigators are using evidence collected in both outbreaks to help identify the possible cause of the contamination in these events.
The current outbreak appears to be ongoing as illnesses linked to romaine lettuce continue to be reported. These recent illnesses indicate that contaminated romaine lettuce may still be on the market, including in restaurants, grocery stores and any establishments that serve food. At this time, the investigation evidence in Ontario, Quebec, and New Brunswick suggests that there is a risk of E. coli infections associated with eating romaine lettuce.
As the risk is ongoing, the Public Health Agency of Canada is advising individuals in Ontario, Quebec, and New Brunswick to avoid eating romaine lettuce and salad mixes containing romaine lettuce until more is known about the outbreak and the cause of contamination. Residents in impacted provinces are also advised to discard any romaine lettuce in their home and to properly wash and sanitize any containers or bins that have come in contact with romaine lettuce.
Currently, there is no evidence to suggest that residents in other parts of Canada are affected by this outbreak. The U.S. CDC has also issued communications with similar advice for U.S individuals. The outbreak investigation is ongoing, and this public health notice will be updated as the Canadian investigation evolves.
How does lettuce become contaminated with E. coli
E. coli are bacteria that live naturally in the intestines of cattle, poultry and other animals. A common source of E. coli illness is raw fruits and vegetables that have come in contact with feces from infected animals. Leafy greens, such as lettuce, can become contaminated in the field by soil, water, animals or improperly composted manure. Lettuce can also be contaminated by bacteria during and after harvest from handling, storing and transporting the produce.
Contamination in lettuce is also possible at the grocery store, in the refrigerator, or from counters and cutting boards through cross-contamination with harmful bacteria from raw meat, poultry or seafood. Most E. coli strains are harmless to humans, but some varieties cause illness.
In Canada, as of November 23, 2018, there have been 22 confirmed cases of E. coli illness investigated in Ontario (4), Quebec (17), and New Brunswick (1). Individuals became sick between mid-October and early November 2018. Eight individuals have been hospitalized, and one individual suffered from hemolytic-uremic syndrome (HUS), which is a severe complication that can result from an E. coli infection. No deaths have been reported. Individuals who became ill are between 5 and 93 years of age. The cases are evenly distributed among male and female individuals.
Most of the individuals who became sick reported eating romaine lettuce before their illnesses occurred. Individuals reported eating romaine lettuce at home, as well as in prepared salads purchased at grocery stores, or from menu items ordered at restaurants and fast food chains.
The Canadian Food Inspection Agency (CFIA) is working with public health officials and the U.S. FDA to determine the source of the romaine lettuce that ill individuals were exposed to. As part of the food safety investigation, romaine lettuce is being sampled and tested.
To date, all products that have been tested have been negative for E. coli. As no contaminated product has been found in the marketplace and the source of the contamination has not been identified, there have been no product recalls in Canada or the U.S associated with this outbreak. If a specific brand or source of romaine lettuce is identified in Canada the CFIA will take the necessary steps to protect the public, including recalling the product as required.
Who is most at risk
This outbreak strain known as E. coli O157 is more likely than other strains to cause severe illness. Pregnant women, those with weakened immune systems, young children and older adults are most at risk for developing serious complications.
Most people who become ill from an E. coli infection will recover completely on their own. However, some people may have a more serious illness that requires hospital care, or long-lasting health effects. In rare cases, some individuals may develop life-threatening symptoms, including stroke, kidney failure and seizures, which could result in death. It is possible for some people to be infected with the bacteria and to not get sick or show any symptoms, but to still be able to spread the infection to others.
What you should do to protect your health
It is difficult to know whether a product is contaminated with E. coli because you can’t see, smell or taste it. Romaine lettuce can have a shelf life of up to five weeks, and therefore it is possible that contaminated romaine lettuce purchased over the past few weeks may still be in your home.
Restaurant and retailers may also still be selling romaine lettuce products. Consumers are advised to use the information in this public health notice to help make informed decisions about their own personal health situations. Individuals in Ontario, Quebec and New Brunswick should avoid eating romaine lettuce and salad mixes containing romaine lettuce until more is known about the outbreak and the cause of contamination. Residents in impacted provinces are also advised to discard any romaine lettuce in their home, and to properly wash and sanitize any containers or bins that have come in contact with romaine lettuce.
This advice includes all types or uses of romaine lettuce, such as whole heads of romaine, hearts of romaine, and bags and boxes of precut lettuce and salad mixes that contain romaine, including baby romaine, spring mix, and Caesar salad.
People infected with E. coli can have a wide range of symptoms. Some do not get sick at all, though they can still spread the infection to others. Others may feel as though they have a bad case of upset stomach. In some cases, individuals become seriously ill and must be hospitalized.
The following symptoms can appear within one to ten days after contact with the bacteria:
- mild fever
- severe stomach cramps
- watery or bloody diarrhea
Most symptoms end within five to ten days. There is no real treatment for E. coli infections, other than monitoring the illness, providing comfort, and preventing dehydration through proper hydration and nutrition. People who develop complications may need further treatment, like dialysis for kidney failure. You should contact your health care provider if symptoms persist.
What the Government of Canada is doing
The Government of Canada is committed to food safety. The Public Health Agency of Canada leads the human health investigation into an outbreak, and is in regular contact with its federal, provincial and territorial partners to monitor the situation and to collaborate on steps to address an outbreak.
Health Canada provides food-related health risk assessments to determine whether the presence of a certain substance or microorganism poses a health risk to consumers.
The Canadian Food Inspection Agency conducts food safety investigations into the possible food source of an outbreak.
The Government of Canada will continue to update Canadians as new information related to this investigation becomes available.
The figure below is an epi curve for this outbreak. This information is used by outbreak investigators to show when illnesses began, when they peak, and when they trail off. It can take several weeks from the time a person becomes ill to when this illness is reported and testing confirms a link to the outbreak. Data are available for 22 cases.
Figure 1: Number of people infected with E. coli O157