Outbreak of Escherichia coli 0157:H7 related to animal contact at a petting zoo.
OBJECTIVE
To determine the cause of an outbreak of Escherichia coli 0157:H7 related to animal exposures so that further transmission could be prevented.


METHODS
Description of laboratory investigations and a case control study.


METHODS
Agricultural pavilion at an annual fair in Ontario.


METHODS
People with laboratory evidence of E coli 0157:H7 (seven people) and others with diarrhea (155 people) who called the health unit following a media release were interviewed. Animals that were accessed most frequently by the public in the agriculture pavilion were tested for E coli 0157:H7. In the case control study, a case was defined as someone with laboratory confirmed E coli 0157:H7, or someone who developed severe or bloody diarrhea two to eight days after attending the agricultural pavilion at the fair (61 people). A convenience sample of people who attended the agricultural pavilion but did not develop diarrhea was selected as the control group (89 people).


METHODS
Human and animal E coli 0157:H7 specimens were subtyped. Cases and controls were interviewed using a standardized questionnaire.


RESULTS
Subtyping of the seven human isolates of E coli 0157:H7 revealed five that were of an extremely uncommon phage type. Three samples from goats and one from sheep at the petting zoo in the agricultural pavilion were of this same phage type. The case control study also implicated goats (odds ratio [OR] 3.65; 95% CI 1.63 to 8.52) and sheep (OR 2.94; 95% CI 1.33 to 6.57) from the petting zoo.


CONCLUSIONS
Results of this investigation suggest strongly that the goats and sheep from the petting zoo were the source of this outbreak of E coli 0157:H7.
Warshawsky
Bryna
B
Middlesex-London Health Unit, London.
Gutmanis
Iris
I
Henry
Bonnie
B
Dow
Joanne
J
Reffle
Jim
J
Pollett
Graham
G
Ahmed
Rafiq
R
Aldom
John
J
Alves
David
D
Chagla
Abdul
A
Ciebin
Bruce
B
Kolbe
Faron
F
Jamieson
Frances
F
Rodgers
Frank
F