title: A waterborne outbreak of Escherichia coli O157:H7 infections and hemolytic uremic syndrome: implications for rural water systems.
abstract: In the summer of 1998, a large outbreak of Escherichia coli O157:H7 infections occurred in Alpine, Wyoming. We identified 157 ill persons; stool from 71 (45%) yielded E. coli O157:H7. In two cohort studies, illness was significantly associated with drinking municipal water (town residents: adjusted odds ratio=10.1, 95% confidence intervals [CI]=1.8-56.4; visitors attending family reunion: relative risk=9.0, 95% CI=1.3-63.3). The unchlorinated water supply had microbiologic evidence of fecal organisms and the potential for chronic contamination with surface water. Among persons exposed to water, the attack rate was significantly lower in town residents than in visitors (23% vs. 50%, p<0.01) and decreased with increasing age. The lower attack rate among exposed residents, especially adults, is consistent with the acquisition of partial immunity following long-term exposure. Serologic data, although limited, may support this finding. Contamination of small, unprotected water systems may be an increasing public health risk.
authors.affiliation: Foodborne and Diarrheal Diseases Branch, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA. sco2@cdc.gov
authors.forename: Sonja J
authors.initials: SJ
authors.lastname: Olsen
authors.forename: Gayle
authors.initials: G
authors.lastname: Miller
authors.forename: Thomas
authors.initials: T
authors.lastname: Breuer
authors.forename: Malinda
authors.initials: M
authors.lastname: Kennedy
authors.forename: Charles
authors.initials: C
authors.lastname: Higgins
authors.forename: Jim
authors.initials: J
authors.lastname: Walford
authors.forename: Gary
authors.initials: G
authors.lastname: McKee
authors.forename: Kim
authors.initials: K
authors.lastname: Fox
authors.forename: William
authors.initials: W
authors.lastname: Bibb
authors.forename: Paul
authors.initials: P
authors.lastname: Mead
mesh_terms: D000328:Adult; D002675:Child, Preschool; D015331:Cohort Studies; D003967:Diarrhea / Q000150:complications / Q000453:epidemiology / Q000382:microbiology; D004196:Disease Outbreaks; D004326:Drinking; D004927:Escherichia coli Infections / Q000150:complications / Q000453:epidemiology* / Q000382:microbiology; D019453:Escherichia coli O157 / Q000302:isolation & purification* / Q000502:physiology; D005260:Female; D006463:Hemolytic-Uremic Syndrome / Q000150:complications / Q000453:epidemiology* / Q000382:microbiology*; D006801:Humans; D007223:Infant; D008297:Male; D012189:Retrospective Studies; D012307:Risk Factors; D012424:Rural Population; D014871:Water Microbiology / Q000592:standards; D014881:Water Supply / Q000032:analysis / Q000592:standards; D014959:Wyoming / Q000453:epidemiology