title: An outbreak of Escherichia coli O157 infection following exposure to a contaminated building.
abstract: BACKGROUND
  Infection with Escherichia coli O157 causes an estimated 70 000 diarrheal illnesses per year in the United States and can result in hemolytic-uremic syndrome and death. Environmental contamination with E coli O157 may be a public health problem.
  
  
  OBJECTIVE
  To determine risk factors for E coli O157 infection during an outbreak investigation at a county fair and to evaluate environmental contamination as a possible cause of the outbreak.
  
  
  METHODS
  Case-control study of 23 patients (median age, 15 years) and 53 age-matched controls who had attended the Lorain County, Ohio, fair between August 20 and August 26, 2001. Case-patients had laboratory-confirmed E coli O157 infection, hemolytic-uremic syndrome, or bloody diarrhea within 7 days of attending the fair; controls attended the fair and did not have diarrhea.
  
  
  METHODS
  Risk factors for infection and isolates of E coli O157 from environmental specimens.
  
  
  RESULTS
  Six (26%) case-patients were hospitalized and 2 (9%) developed hemolytic-uremic syndrome. Case-patients were more likely than controls to have visited building A (a multipurpose community facility on the fairgrounds; matched odds ratio [MOR], 21.4 [95% confidence interval [CI], 2.7-170.7]). Among visitors to building A, illness was independently associated with attending a dance in the building (MOR, 7.5; 95% CI, 1.4-41.2), handling sawdust from the floor (MOR, 4.6; 95% CI, 1.1-20.0), or eating and/or drinking in the building (MOR, 4.5; 95% CI, 1.2-16.6). Twenty-four (44%) of 54 specimens collected from building A 6 weeks after the fair grew Shiga toxin-producing E coli O157. Isolates from sawdust, the rafters, and other surfaces were identical by molecular fingerprinting to patient isolates. Sawdust specimens collected 42 weeks after the fair also grew the same E coli O157 strain.
  
  
  CONCLUSIONS
  Absence of evidence implicating specific food or beverage sources and the recovery of E coli O157 from the rafters suggest that airborne dispersion of bacteria contributed to the contamination. Because E coli O157 can survive in the environment for more than 10 months, humans may be at risk of infection long after an environment is initially contaminated.
authors.affiliation: Foodborne and Diarrheal Diseases Branch, Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Ga., USA. jvarma@cdc.gov
authors.forename: Jay K
authors.initials: JK
authors.lastname: Varma
authors.forename: Katherine D
authors.initials: KD
authors.lastname: Greene
authors.forename: Megan E
authors.initials: ME
authors.lastname: Reller
authors.forename: Stephanie M
authors.initials: SM
authors.lastname: DeLong
authors.forename: Janine
authors.initials: J
authors.lastname: Trottier
authors.forename: Scott F
authors.initials: SF
authors.lastname: Nowicki
authors.forename: Mary
authors.initials: M
authors.lastname: DiOrio
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Koch
authors.forename: Tammy L
authors.initials: TL
authors.lastname: Bannerman
authors.forename: Steven T
authors.initials: ST
authors.lastname: York
authors.forename: Mary-Ann
authors.initials: MA
authors.lastname: Lambert-Fair
authors.forename: Joy G
authors.initials: JG
authors.lastname: Wells
authors.forename: Paul S
authors.initials: PS
authors.lastname: Mead
mesh_terms: D000293:Adolescent; D000328:Adult; D016902:Air Pollution, Indoor / Q000009:adverse effects / Q000032:analysis; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003967:Diarrhea / Q000453:epidemiology / Q000382:microbiology; D004196:Disease Outbreaks; D004781:Environmental Exposure / Q000009:adverse effects / Q000032:analysis; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000209:etiology; D019453:Escherichia coli O157 / Q000302:isolation & purification*; D005260:Female; D006463:Hemolytic-Uremic Syndrome / Q000453:epidemiology / Q000209:etiology; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D009820:Ohio / Q000453:epidemiology; D012307:Risk Factors