Walkerton Outbreak - May 2000


The community of Walkerton experienced an outbreak of illness that was linked to the municipal water supply. On Sunday May 21, 2000 the Medical Officer of Health issued a Boil Water Advisory to the residents of Walkerton. That Advisory was lifted on December 5, 2000.


An epidemiological investigation included both a descriptive study and a cross-sectional study. Intensive case-finding for the descriptive study ultimately led to the identification of 1346 reported cases of gastroenteritis with exposure to Walkerton municipal water. Among these, 799 were residents of the town of Walkerton. Based on estimates derived from the cross-sectional study, the number of Walkerton residents that became ill was approximately 1286. The overall estimated number of cases associated with the outbreak was over 2300 people.

Hemolytic Uremic Syndrome (HUS)

Under 10% of individuals with E. Coli 0157:H7 infection will develop Hemolytic Uremic Syndrome (HUS). HUS is a serious complication of E. Coli infection that may lead to kidney failure. Symptoms of HUS may include a decrease in the amount of urine produced, swelling in the face, hands, and feet, paleness of the skin, irritability and fatigue. Young children (especially under 5 years of age) and the elderly are most at risk for HUS. It is important to watch for the signs of HUS even after diarrhea has stopped.

Anyone with these symptoms, see your physician immediately.


External Links


The Investigative Report of the Walkerton Outbreak of Waterborne Gastroenteritis

MAY – JUNE, 2000

Released: October 10, 2000

Executive Summary


Appendix A

Appendix B

Appendix C

Appendix D

Appendix E

Appendix F

Appendix G

Appendix H



Grey Bruce Health Unit Archived Documents



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