Public Health Notice - Outbreak of E. coli infections linked to romaine lettuce

    May 10, 2018

    Why should you take note?

    The United States Centers for Disease Control and Prevention (U.S. CDC) and the United States Food and Drug Administration (U.S. FDA) are investigating an outbreak of Escherichia coli O157, commonly called E. coli, linked to romaine lettuce from the Yuma growing regions in the United States (U.S.). E. coli can cause a serious, life-threatening illness.

    In Canada, there are six Canadian illnesses of E. coli O157 with a similar genetic fingerprint to illnesses reported in the U.S. investigation. The Public Health Agency of Canada is collaborating with federal and provincial public health partners to investigate these illnesses. Two of the six individuals who became sick reported travelling to the U.S. before the onset of their illness. Three individuals became infected in Canada, and information is pending for the fourth individual. Based on the ongoing U.S. outbreak investigation, and the information provided by individuals who became sick, the likely source of the outbreak in Canada is romaine lettuce.

    In Canada, based on the current information related to the Canadian outbreak investigation, the risk to Canadians is low. The U.S. FDA has reported that romaine lettuce coming from the Yuma growing region in the U.S. is no longer being produced and distributed, therefore reducing the potential for exposure to contaminated product on the marketplace given that leafy greens have a shelf-life of 21 days. The Yuma growing region includes part of western Arizona and extends into the Imperial Valley of southeastern California, but does not include Salinas Valley or other growing regions in California.

    The Canadian investigation is ongoing. Given the evolving nature of this outbreak, the Public Health Agency of Canada is advising all Canadians to be aware of this ongoing investigation and the U.S. E. coli outbreak linked to romaine lettuce. Canadians who are travelling to the U.S., or who shop for groceries across the border and purchase romaine lettuce in the U.S. are advised to follow the U.S. CDC's advice for U.S. consumers found on their website.

    If there is updated public health advice to provide or any new information related to the Canadian investigation, the Public Health Agency of Canada and its partners will notify Canadians by issuing an updated public health notice.

    Investigation summary

    As of May 9, 2018, there are six Canadian cases of E. coli O157 that are genetically similar to the U.S. outbreak linked to romaine lettuce coming from the Yuma growing region in the U.S. The six Canadian illnesses are reported in four provinces: British Columbia (1), Alberta (1), Saskatchewan (2), and Ontario (2). Individuals became sick between late March and mid-April 2018. One of the Canadian cases was hospitalized and no deaths have been reported in Canada. Individuals who became ill were between 13 and 68 years of age. The majority of cases (67%) were female.

    In the Canadian investigation, among the six cases, most of the individuals who became sick reported having eaten romaine lettuce at home, or in prepared salads purchased at grocery stores, restaurants and fast food chains, before their illnesses occurred. Two Canadians did report travelling to the U.S. before getting sick and eating romaine lettuce while they were there.

    If it is determined that contaminated romaine lettuce is in the Canadian market, the Canadian Food Inspection Agency will take the necessary steps to protect the public, including recalling the product as required. Currently there are no Food Recall Warnings associated with this outbreak.

    Who is most at risk?

    Although anyone can get an E. coli infection, pregnant women, those with weakened immune systems, young children, and older adults are most at risk for developing serious complications. This is especially true for this outbreak strain of E. coli (O157), which is more likely to cause severe illness than other E. coli strains in Canada.

    Most people with an E. coli infection will become ill for a few days and then recover fully. Some E. coli infections can be life-threatening, though this is rare.

    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, contaminated 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.

    What should you do to protect your health?

    Canadians who are travelling to the U.S., or who shop for groceries across the border and purchase romaine lettuce in the U.S. are advised to follow the U.S. CDC's advice for U.S. consumers found on their website.

    In general, it is difficult to know whether a product is contaminated with E. coli because you can't see, smell or taste it. The best way to protect your health is to practice safe food-handling on a daily basis. The following food safety tips for lettuce can help to reduce the risk of an E. coli infection, but they will not fully eliminate the risk of illness.

    Wash your hands thoroughly with warm water and soap for at least 20 seconds, before and after handling lettuce.

    Unwashed lettuce, including whole heads of lettuce sold in sealed bags, should be handled and washed using these steps:
    Discard outer leaves of fresh lettuce.
    Wash unpackaged lettuce under fresh, cool running water. There is no need to use anything other than water to wash lettuce. Washing it gently with water is as effective as using produce cleansers.
    Keep rinsing your lettuce until all of the dirt has been washed away.
    Don't soak lettuce in a sink full of water. It can become contaminated by bacteria in the sink.
    Store lettuce in the refrigerator for up to seven days. Discard when leaves become wilted or brown.
    Use warm water and soap to thoroughly wash all utensils, countertops, cutting boards and storage containers before and after handling lettuce to avoid cross-contamination.

    Ready-to-eat lettuce products sold in sealed packages and labelled as washed, pre-washed or triple washed do not need to be washed again. These products should also be refrigerated and used before the expiration date.
    What are the symptoms?

    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. While most people recover completely on their own, some people may have a more serious illness that requires hospital care, or may lead to 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.

    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.

    Public Health Agency of Canada