title: The epidemiology of travel-related Salmonella Enteritidis in Ontario, Canada, 2010-2011.
abstract: BACKGROUND
  Increases in the number of salmonellosis cases due to Salmonella Enteritidis (SE) in 2010 and 2011 prompted a public health investigation in Ontario, Canada. In this report, we describe the current epidemiology of travel-related (TR) SE, compare demographics, symptoms and phage types (PTs) of TR and domestically-acquired (DA) cases, and estimate the odds of acquiring SE by region of the world visited.
  
  
  METHODS
  All incident cases of culture confirmed SE in Ontario obtained from isolates and specimens submitted to public health laboratories were included in this study. Demographic and illness characteristics of TR and DA cases were compared. A national travel survey was used to provide estimates for the number of travellers to various destinations to approximate rates of SE in travellers. Multivariate logistic regression was used to estimate the odds of acquiring SE when travelling to various world regions.
  
  
  RESULTS
  Overall, 51.9% of SE cases were TR during the study period. This ranged from 35.7% TR cases in the summer travel period to 65.1% TR cases in the winter travel period. Compared to DA cases, TR cases were older and were less likely to seek hospital care. For Ontario travellers, the adjusted odds of acquiring SE was the highest for the Caribbean (OR 37.29, 95% CI 17.87-77.82) when compared to Europe. Certain PTs were more commonly associated with travel (e.g., 1, 4, 5b, 7a, Atypical) than with domestic infection. Of the TR cases, 88.9% were associated with travel to the Caribbean and Mexico region, of whom 90.1% reported staying on a resort. Within this region, there were distinct associations between PTs and countries.
  
  
  CONCLUSIONS
  There is a large burden of TR illness from SE in Ontario. Accurate classification of cases by travel history is important to better understand the source of infections. The findings emphasize the need to make travellers, especially to the Caribbean, and health professionals who provide advice to travellers, aware of this risk. The findings may be generalized to other jurisdictions with travel behaviours in their residents similar to Ontario residents.
authors.affiliation: Public Health Ontario, 480 University Ave, Toronto, M5G 1V2, Canada.
authors.forename: Mary-Kathryn
authors.initials: MK
authors.lastname: Tighe
authors.forename: Rachel
authors.initials: R
authors.lastname: Savage
authors.forename: Linda
authors.initials: L
authors.lastname: Vrbova
authors.forename: Miriam
authors.initials: M
authors.lastname: Toolan
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Whitfield
authors.forename: Csaba
authors.initials: C
authors.lastname: Varga
authors.forename: Brenda
authors.initials: B
authors.lastname: Lee
authors.forename: Vanessa
authors.initials: V
authors.lastname: Allen
authors.forename: Anne
authors.initials: A
authors.lastname: Maki
authors.forename: Ryan
authors.initials: R
authors.lastname: Walton
authors.forename: Caitlin
authors.initials: C
authors.lastname: Johnson
authors.forename: Badal
authors.initials: B
authors.lastname: Dhar
authors.forename: Rafiq
authors.initials: R
authors.lastname: Ahmed
authors.forename: Natasha S
authors.initials: NS
authors.lastname: Crowcroft
authors.forename: Dean
authors.initials: D
authors.lastname: Middleton
mesh_terms: D000293:Adolescent; D000328:Adult; D000958:Antigua and Barbuda; D016009:Chi-Square Distribution; D002648:Child; D002675:Child, Preschool; D003462:Cuba; D018562:Disease Transmission, Infectious; D004293:Dominican Republic; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007563:Jamaica; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009864:Ontario / Q000453:epidemiology; D010342:Patient Acceptance of Health Care; D012480:Salmonella Infections / Q000453:epidemiology* / Q000503:physiopathology; D012477:Salmonella enteritidis; D014195:Travel