As of November 23, 2015, 19 people infected with the outbreak strain of E. coli O157:H7 have been reported from 7 states. One DNA fingerprint (outbreak strain) is included in this investigation. The majority of illnesses have been reported from states in the western United States. The number of ill people reported from each state is as follows: California (1), Colorado (4), Missouri (1), Montana (6), Utah (5), Virginia (1), and Washington (1).

big-map-11-24-2015

Among people for whom information is available, illnesses started on dates ranging from October 6, 2015 to November 3, 2015. Ill people range in age from 5 years to 84, with a median age of 18. Fifty-seven percent of ill people are female. Five (29%) people reported being hospitalized, and two people developed hemolytic uremic syndrome (HUS), a type of kidney failure. No deaths have been reported.

This outbreak can be illustrated with a chart showing the number of people who became ill each day. This chart is called an epidemic curve or epi curve. Illnesses that occurred after November 10, 2015, might not be reported yet due to the time it takes between when a person becomes ill and when the illness is reported. This takes an average of 2 to 3 weeks.

big-epi-11-24-2015

Preliminary laboratory evidence indicates that a celery and onion diced blend produced by Taylor Farms Pacific, Inc. may be contaminated with E. coli O157:H7. This product was used to make the Costco rotisserie chicken salad eaten by ill people in this outbreak.

14 (88%) of 16 people purchased or ate rotisserie chicken salad from Costco in the week before illness started.

The Montana Public Health Laboratory tested a sample of celery and onion diced blend collected from a Costco location. Preliminary results indicated the presence of E. coli O157:H7. Laboratory testing is ongoing to isolate the E. coli bacteria and then determine the DNA fingerprint.

As a result of the preliminary laboratory results, on November 26, 2015, Taylor Farms Pacific, Inc., voluntarily recalled multiple products containing celery because they may be contaminated with E. coli O157:H7.

Questions:

  1. Has the Montana “preliminary result” been confirmed as E. coli O157:H7, and is it a match to the outbreak strain?
  2. If a match, was it the onion or celery that tested position?  Another ingredient?
  3. Why does this seem like a celery recall?
  4. Which of the 19 reported case did not eat Costco rotisserie chicken salad, if any?