In October 2013 routine surveillance of reported E. Coli O157 cases triggered an investigation of an outbreak that occurred at a petting zoo at a fall harvest festival in Brooklyn Park, Minnesota. The two case patients had attended the festival on October 12. Both cases were hospitalized with hemolytic uremic syndrowe and recovered.

Both cases reported entering an animal pen and petting sheep, goats and possibly calves. Eight environmental animal fecal samples were collected from the animal pen and one swab of the front gate was obtained. The Minnesota Department of Health Public Health Laboratory isolated E. coli O157 subtype MN129ECB221 from two environmental samples as well as fecal samples obtained from two calves and one goat. This pattern was indistinguishable from one of the case isolates. Three different subtypes were isolated in one calf. Non-O157 E. coli was identified in the sheep and 6 goats.

Minnesota public health investigators concluded this was an outbreak of E. coli O157:H7 infections associated with animal contact at a petting zoo at a fall harvest festival.