Epidemiology and Infection

Original Papers


Risk factors for sporadic domestically acquired Salmonella serovar Enteritidis infections: a case-control study in Ontario, Canada, 2011

D. MIDDLETONa1a2 c1, R. SAVAGEa1, M. K. TIGHEa1, L. VRBOVAa1a3a4, R. WALTONa1a2a3, Y. WHITFIELDa1a5, C. VARGAa6a7, B. LEEa1a5, L. ROSELLAa1a2, B. DHARa1, C. JOHNSONa1a2, R. AHMEDa8, V. G. ALLENa1 and N. S. CROWCROFTa1a2

a1 Public Health Ontario, Toronto, ON, Canada

a2 Dalla Lana School of Public Health, University of Toronto, Health Sciences Building, Toronto ON, Canada

a3 Canadian Field Epidemiology Program, Public Health Agency of Canada, Ottawa, ON, Canada

a4 School of Population and Public Health, University of British Columbia, Vancouver, BC, Canada

a5 Ontario Ministry of Health and Long-Term Care, Toronto, ON, Canada

a6 Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada

a7 Ontario Ministry of Agriculture, Food, and Rural Affairs, Guelph, ON, Canada

a8 National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MN, Canada


In Ontario, Canada, the number of Salmonella Enteritidis (SE) cases increased over the years 2005–2010. A population-based case-control study was undertaken from January to August 2011 for the purpose of identifying risk factors for acquiring illness due to SE within Ontario. A total of 199 cases and 241 controls were enrolled. After adjustment for confounders, consuming any poultry meat [adjusted odds ratio (aOR) 2·24, 95% confidence interval (CI) 1·31–3·83], processed chicken (aOR 3·32, 95% CI 1·26–8·76) and not washing hands following handling of raw eggs (OR 2·82, 95% CI 1·48–5·37) were significantly associated with SE infection. The population attributable fraction was 46% for any poultry meat consumption and 10% for processed chicken. Poultry meat continues to be identified as a risk factor for SE illness. Control of SE at source, as well as proper food handling practices, are required to reduce the number of SE cases.

(Received December 04 2012)

(Revised June 20 2013)

(Accepted July 16 2013)

(Online publication September 13 2013)

Key words

  • Case-control study;
  • human;
  • phage type;
  • population attributable fraction;
  • Salmonella Enteritidis


c1 Author for correspondence: Dr D. Middleton, Public Health Ontario, 3rd Floor, 480 University Avenue, Toronto, ON, Canada, M5G 1V2. (Email: Dean.Middleton@oahpp.ca)