title: Escherichia coli O157:H7 infections associated with consumption of locally grown strawberries contaminated by deer.
abstract: BACKGROUND
  An outbreak of Escherichia coli O157:H7 was identified in Oregon through an increase in Shiga toxin-producing E. coli cases with an indistinguishable, novel pulsed-field gel electrophoresis (PFGE) subtyping pattern.
  
  
  METHODS
  We defined confirmed cases as persons from whom E. coli O157:H7 with the outbreak PFGE pattern was cultured during July-August 2011, and presumptive cases as persons having a household relationship with a case testing positive for E. coli O157:H7 and coincident diarrheal illness. We conducted an investigation that included structured hypothesis-generating interviews, a matched case-control study, and environmental and traceback investigations.
  
  
  RESULTS
  We identified 15 cases. Six cases were hospitalized, including 4 with hemolytic uremic syndrome (HUS). Two cases with HUS died. Illness was significantly associated with strawberry consumption from roadside stands or farmers' markets (matched odds ratio, 19.6; 95% confidence interval, 2.9-∞). A single farm was identified as the source of contaminated strawberries. Ten of 111 (9%) initial environmental samples from farm A were positive for E. coli O157:H7. All samples testing positive for E. coli O157:H7 contained deer feces, and 5 tested farm fields had ≥ 1 sample positive with the outbreak PFGE pattern.
  
  
  CONCLUSIONS
  The investigation identified fresh strawberries as a novel vehicle for E. coli O157:H7 infection, implicated deer feces as the source of contamination, and highlights problems concerning produce contamination by wildlife and regulatory exemptions for locally grown produce. A comprehensive hypothesis-generating questionnaire enabled rapid identification of the implicated product. Good agricultural practices are key barriers to wildlife fecal contamination of produce.
authors.affiliation: Oregon Public Health Division, Oregon Health Authority, Portland.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Laidler
authors.forename: Mathieu
authors.initials: M
authors.lastname: Tourdjman
authors.forename: Genevieve L
authors.initials: GL
authors.lastname: Buser
authors.forename: Trevor
authors.initials: T
authors.lastname: Hostetler
authors.forename: Kimberly K
authors.initials: KK
authors.lastname: Repp
authors.forename: Richard
authors.initials: R
authors.lastname: Leman
authors.forename: Mansour
authors.initials: M
authors.lastname: Samadpour
authors.forename: William E
authors.initials: WE
authors.lastname: Keene
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D002648:Child; D002675:Child, Preschool; D003670:Deer; D004197:Disease Reservoirs; D004927:Escherichia coli Infections / Q000382:microbiology* / Q000635:transmission*; D019453:Escherichia coli O157 / Q000235:genetics / Q000302:isolation & purification*; D005243:Feces / Q000382:microbiology; D005260:Female; D005516:Food Microbiology; D005517:Foodborne Diseases / Q000382:microbiology*; D031985:Fragaria / Q000382:microbiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D055815:Young Adult
keywords: Escherichia coli O157; Fragaria; STEC; deer; foodborne disease outbreak