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  Verotoxin-producing Escherichia coli (VTEC)

Outbreak Investigation:  Verotoxin-producing E. coli 
The national outbreak of verotoxin-producing E. coli (VTEC) O157 infections linked to romaine lettuce appears to be over.  As of January 10, 2018, 42 cases have been reported from five provinces in eastern Canada, including eight cases from Ontario.  Romaine lettuce has been identified as a likely source of illness, but the cause of contamination has not been identified.  No individuals in Canada have had illness onset dates beyond December 12, 2017.  As a result, the outbreak appears to be over, and the risk to Canadians has returned to normal.  It is no longer advised that individuals in the affected provinces consider consuming other types of lettuce, instead of romaine lettuce. All Canadians are advised to always use safe food handling tips for preparing lettuce.  Public Health Ontario continues to collaborate with the Ministry of Health and Long-term Care, and other local, provincial, and federal partners in the investigation into the possible source of contamination for this outbreak.  Additional information can be found on the Public Health Agency of Canada’s Public Health Notice.  

On December 28, 2017, the United States Centers for Disease Control and Prevention issued a media statement regarding a multistate outbreak of E. coli infections that are genetically related to the outbreak in Canada. On January 10, 2018, an updated media statement was released by the United States Centers for Disease Control and Prevention.


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Enteric, Zoonotic and Vector-Borne Diseases

While, most strains of E. coli do not cause disease, Verotoxin-producing Escherichia coli (VTEC) is the most frequently identified subgroup of E. coli that causes illness in North America. It can be found in cattle, goats, sheep, and sometimes humans. This type of E. coli was first recognized in 1982 as a result of an outbreak investigation associated with undercooked hamburgers.

VTEC can be transmitted through ingestion of food or water that has been contaminated by the feces of animals or infected persons. Undercooked ground beef, fresh produce such as lettuce, spinach and sprouts, unpasteurized milk and fruit juices, and inadequately treated drinking water have been implicated in large outbreaks of VTEC in North America. Contact with animals and their environments (such as farms or petting zoos) and person-to-person contact with individuals suffering from VTEC infections can also be sources of transmission. Documented outbreaks of person-to-person transmission most often occur in childcare settings, households and institutional settings.

Symptoms can appear between 2 and 10 days with a median of 3-4 days, and can typically include bloody or non-bloody diarrhea, vomiting and severe abdominal cramping. Complications may include Hemolytic Uremic Syndrome (HUS), which can occur in up to 8% of infected children. Proper personal hygiene and safe food handling practices are key to preventing the spread of VTEC.

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Page last updated: 17/01/2018 3:50 PM
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