Module 4: Chronology

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CHRONOLOGY OF EVENTS:  2014-175 E. coli O157:H7 in MB, SK, AB, and BC

Day 1: Monday, July 21, 2014 (6 confirmed cases: MB-2, SK-3, AB-1)

·        National Enteric Surveillance Program (NESP) reports that E. coli O157 is above expected levels nationally, as well as in Saskatchewan and Manitoba for the week of July 13-19, 2014.

·        PulseNet Canada reports a multi-provincial cluster of six E. coli O157:H7 isolates with the same PFGE patterns in Manitoba (2), Saskatchewan (3) and Alberta (1).

Day 2: Tuesday, July 22, 2014 (6 confirmed cases: MB-2, SK-3, AB-1)

·        OICC Assessment call is held with CFIA, Health Canada, National Microbiology Laboratory, and provincial public health partners in Manitoba, Saskatchewan, and Alberta. A national OICC activated.

·        SK reports five unconfirmed cases with clinical symptoms that attended the same Canada Day BBQ as two confirmed cases from SK.

·        CFIA is beginning traceback on lettuce.

Day 3: Wednesday, July 23, 2014 (12 confirmed cases: MB-4, SK-4, AB-3, BC-1)

·        Six additional PFGE matches are reported by PulseNet Canada: Saskatchewan (1), Manitoba (2), Alberta (2), and British Columbia (1). The case count is now 12.

·        A technical epidemiology call is held at 14:00. On the call, the provinces agree to interview cases using a standardized E. coli hypothesis generating questionnaire.

Day 5: Friday, July 25, 2014 (12 confirmed cases: MB-4, SK-4, AB-3, BC-1)
·        Eight hypothesis-generating questionnaires are received and analyzed.
Day 8: Monday, July 28, 2014 (12 confirmed cases: MB-4, SK-4, AB-3, BC-1)

·        OICC Call #2 is held.

·        CFIA reports that the lettuce traceback indicates that the distributor of interest does not distribute outside SK.  They will initiate traceback on hamburgers, but require more information.

·        Provinces agree to re-interview cases with a focused questionnaire.

Day 11: Thursday, July 31, 2014 (15 confirmed cases: MB-5, SK-5, AB-4, BC-1)

·        OICC Call #3 is held.

·        Two new cases with matching PFGE are reported by PulseNet Canada: Saskatchewan (1), Manitoba (1).

·        There is one new case in Alberta that has a similar PFGE pattern. The case definition is expanded to include this PFGE pattern.

·        Four focused questionnaires are received from the provinces.

·        Food samples will be collected from two case homes (1 in Manitoba, 1 in Saskatchewan). CFIA has also requested pictures of the packaging.

 

Day 13: Saturday, August 2, 2014 (15 confirmed cases: MB-5, SK-5, AB-4, BC-1)

·        OICC Call #4 is held.

·        Manitoba and Saskatchewan have submitted frozen burger samples from case homes to CFIA.

·        Focused questionnaires and CFIA traceback reveal that two brands of frozen burgers reported by three cases were produced at the same facility.

·        Environmental samples from the facility as well as samples of the implicated products, products produced before and those produced after the implicated time frame, will be obtained and tested by the CFIA.

·        Partners agree that PHAC will lead the development of an epidemiological assessment to inform Health Canada’s Health Risk Assessment (HRA)

·        Communications departments agree to coordinate media lines and post at the same time.

Day 14: Sunday, August 3, 2014 (15 confirmed cases: MB-5, SK-5, AB-4, BC-1)

·        Health Risk Assessment completed by Health Canada.

·        CFIA recalls two brands of frozen hamburgers: Happy Burger (1 lot code) and Farmer Fred’s Burgers (2 lot codes).

Day 17: Wednesday, August 6, 2014 (17 confirmed cases: MB-6, SK-5, AB-4, BC-2)

·        OICC Call #5 is held

·        CFIA reports that all product in distribution has been recalled.

·        Two samples of frozen burger from case homes have tested presumptive positive for E. coli.

·        Two new cases are reported: Manitoba (1) and British Columbia (1). There are now 17 cases in total.

·        NML reports that MLVA results are available for 11 cases. All isolates have matching MLVA, including the case with a different BlnI pattern.

Day 18: Thursday, August 7, 2014 (17 confirmed cases: MB-6, SK-5, AB-4, BC-2)
·        Four samples from the recalled lots (unopened boxes of product) tested positive for E. coli O157:H7, E. coli was not detected in the samples from the previous and subsequent lots of hamburgers, or from the environmental samples.
Day 19: Friday, August 8, 2014 (17 confirmed cases: MB-6, SK-5, AB-4, BC-2)
·        The two product samples from case homes are reported positive for the presence of E. coli O157:H7
Day 22: Friday, August 11, 2014 (17 confirmed cases: MB-6, SK-5, AB-4, BC-2)
·        The PFGE patterns for the 4 retail samples and 2 case home samples are reported. All 6 match the outbreak strain.
Day 44: Tuesday, September 2, 2014 (17 confirmed cases: MB-6, SK-5, AB-4, BC-2)
·        Outbreak is declared over. No new cases have been reported after the recall.