Eighteen people infected with the outbreak strain of Listeria have been reported from nine states since July 5, 2015. The number of ill people reported from each state is as follows: Connecticut (1), Indiana (1), Massachusetts (1), Michigan (4), Missouri (2), New Jersey (1), New York (5), Ohio (2), and Pennsylvania (1). Whole genome sequencing has been performed on clinical isolates from all ill people and has shown that the isolates are highly related genetically.
Listeria specimens were collected from ill people between July 5, 2015 and January 31, 2016. Ill people range in age from 3 years to 83, and the median age is 66. Seventy-two percent of ill people are female. All 18 (100%) ill people were hospitalized, including one person from Michigan who died as a result of listeriosis. One of the illnesses reported was in a pregnant woman.
Currently, there are 11 cases of Listeria monocytogenes in five provinces related to this outbreak: Ontario (7), Quebec (1), New Brunswick (1), Prince Edward Island (1), and Newfoundland and Labrador (1).
Individuals became sick between May 2015 and early January 2016. Some of the individuals who became ill have reported eating packaged salads. It is suspected that these salads were produced at the Dole facility in Ohio. The majority of Canadians cases (55%) are female, with an average age of 79 years. All cases have been hospitalized, and three people have died, however it has not been determined if Listeria contributed to the cause of these deaths.
Epidemiologic and laboratory evidence indicate that packaged salads produced at the Dole processing facility in Springfield, Ohio and sold under various brand names are the likely source of this outbreak.