Last night Food Safety News reported that the Arizona Department of Health was reporting a “secondary E. coli case,” linked to Pure Eire Dairy that has thus far sickened over a dozen – mainly children – some with acute kidney failure.

“We have a case of E. coli O157 in a 2-year-old girl that matches by whole genome sequencing the cluster of cases in Washington linked to Pure Eire yogurt. It’s likely she was exposed by a relative (who consumed the product) who traveled from Washington state,” Steve Elliott of the department told Food Safety News.

Outbreaks of foodborne illness nearly always involve both primary and secondary cases, meaning that secondary cases are neither unusual nor rare.  More importantly, a secondary case is, by definition, part of an outbreak.  To an epidemiologist, the person who defines the outbreak, what is definitive is whether a person is infected with the outbreak strain.  Person-to-person transmission of infectious bacteria within a family is well-documented.  See, e.g., K. Ludwig, “Outbreak of Escherichia coli O157:H7 Infection in a Large Family,” Eur. J. Clin. Microb. Infect. Dis. 16:238-41 (1997).  P. Rowe, “Diarrhea in Close Contacts as a Risk Factor for Childhood Hemolytic Uremic Syndrome,” Epidem. Infect. 110:9-16 (1993).

Court’s have previously recognized that food manufacturers are liable to those who are injured through “secondary” exposure in foodborne illness outbreaks.  Almquist v. Finley Sch. Dist. No. 53, 114 Wn. App. 395, 57 P.3d 1191 (2002).

Pure Eire Dairy is as responsible for the kidney failure this Arizona two-year-old suffered as it would be to a child that ate the product directly – there is no “break in the chain.”