title: Swimming-associated haemorrhagic colitis due to Escherichia coli O157:H7 infection: evidence of prolonged contamination of a fresh water lake.
abstract: We describe an Escherichia coli O157:H7 outbreak associated with a fresh water lake at a county park. Campers were surveyed for diarrhoeal illness within 10 days of their visit, and a case-control study of day visitors was conducted. A confirmed case was a symptomatic person with a stool culture positive for E. coli O157:H7 and a probable case was a person with bloody diarrhoea. Clinical isolates of E. coli O157 were subtyped by pulsed field gel electrophoresis (PFGE). In the camper survey, 12 (38%) of 32 swimmers had a diarrhoeal illness (relative risk [RR] = 12.4; 95% confidence interval [CI] = 1.7-89.7). For the case-control study, the 12 cases were more likely than controls to have purposefully ingested lake water (odds ratio [OR] = 6.9, 95% CI = 0.9-55.8). The PFGE patterns of six clinical isolates were indistinguishable. This report further demonstrates that contaminated fresh-water lakes can be the source of community outbreaks of E. coli O157:H7.
authors.affiliation: Epidemiology Program Office, Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors.forename: D
authors.initials: D
authors.lastname: Ackman
authors.forename: S
authors.initials: S
authors.lastname: Marks
authors.forename: P
authors.initials: P
authors.lastname: Mack
authors.forename: M
authors.initials: M
authors.lastname: Caldwell
authors.forename: T
authors.initials: T
authors.lastname: Root
authors.forename: G
authors.initials: G
authors.lastname: Birkhead
mesh_terms: D000293:Adolescent; D002165:Camping; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003092:Colitis / Q000175:diagnosis / Q000453:epidemiology / Q000382:microbiology*; D003967:Diarrhea / Q000382:microbiology; D016521:Electrophoresis, Gel, Pulsed-Field; D004927:Escherichia coli Infections / Q000175:diagnosis / Q000453:epidemiology* / Q000635:transmission; D019453:Escherichia coli O157; D005243:Feces / Q000382:microbiology; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009518:New York / Q000453:epidemiology; D012307:Risk Factors; D013550:Swimming; D014871:Water Microbiology