Skip directly to site content Skip directly to page options Skip directly to A-Z link Skip directly to A-Z link Skip directly to A-Z link
Volume 22, Number 3—March 2016

Encephalitis, Ontario, Canada, 2002–2013

Alyssa S. Parpia1, Ye Li, Cynthia Chen, Badal Dhar, and Natasha S. CrowcroftComments to Author 
Author affiliations: Public Health Ontario, Toronto, Ontario, Canada (A.S. Parpia, Y. Li, C. Chen, B. Dhar, N.S. Crowcroft); University of Toronto, Toronto (A.S. Parpia, Y. Li, N.S. Crowcroft)

Main Article

Table 3

Univariable and multivariable negative binomial regression model assessing variation in incident encephalitis hospitalizations, Ontario, Canada, and England*

Variable No. (%) cases, N = 6,463 Incidence rate Multivariable analysis
Ontario, 2002–2013
England, 2005–2009†
Adjusted IRR (95% CI) p value Adjusted IRR (95% CI) p value
M 3,417 (52.8) 4.6 Referent <0.0001 Referent 0.002
3,046 (47.1)
0.9 (0.8–0.9)

0.9 (0.9–1.0)

Age group, y
<1 173 (2.7) 10.7 3.9 (3.3–4.5) <0.0001 3.7 (3.2–4.2) <0.001
1–4 377 (5.8) 5.7 2.1 (1.8–2.3) 1.9 (1.7–2.1)
5–19 915 (14.2) 3.2 1.2 (1.1–1.3) 0.9 (0.8–1.0)
20–44 1,486 (23.0) 2.8 Referent Referent
45–64 1,823 (28.2) 4.4 1.6 (1.5–1.8) 1.4 (1.3–1.5)
>65 1,689 (26.1) 8.3 3.0 (2.8–3.2) 1.9 ( 1.8–2.1)

*Incidence is number of cases/100,000 persons. IRR, incident rate ratio.
†Reference (1).

Main Article

  1. Schmidt  A, Bühler  R, Mühlemann  K, Hess  CW, Täuber  MG. Long-term outcome of acute encephalitis of unknown aetiology in adults. Clin Microbiol Infect. 2011;17:6216 . DOIPubMedGoogle Scholar
  2. Khetsuriani  N, Holman  RC, Anderson  LJ. Burden of encephalitis-associated hospitalizations in the United States, 1988–1997. Clin Infect Dis. 2002;35:17582 . DOIPubMedGoogle Scholar
  3. Vora  NM, Holman  RC, Mehal  JM, Steiner  CA, Blanton  J, Sejvar  J. Burden of encephalitis-associated hospitalizations in the United States, 1998–2010. Neurology. 2014;82:44351 . DOIPubMedGoogle Scholar
  4. Kulkarni  MA, Comtois Lecocq  A, Artsob  H, Drebot  MA, Ogden  NH. Epidemiology and aetiology of encephalitis in Canada, 1994–2008: a case for undiagnosed arboviral agents? Epidemiol Infect. 2013;141:224355 . DOIPubMedGoogle Scholar
  5. Barbadoro  P, Marigliano  A, Ricciardi  A, D'Errico  MM, Prospero  E. Trend of hospital utilization for encephalitis. Epidemiol Infect. 2012;140:75364 . DOIPubMedGoogle Scholar
  6. Huppatz  C, Durrheim  DN, Levi  C, Dalton  C, Williams  D, Clements  MS, Etiology of encephalitis in Australia, 1990–2007. Emerg Infect Dis. 2009;15:135965. DOIGoogle Scholar
  7. Granerod  J, Ambrose  HE, Davies  NWS, Clewley  JP, Walsh  AL, Morgan  D, Causes of encephalitis and differences in their clinical presentations in England: a multicentre, population-based prospective study. Lancet Infect Dis. 2010;10:83544 . DOIPubMedGoogle Scholar
  8. Kelly  TA, O’Lorcain  P, Moran  J, Garvey  P, McKeown  P, Connell  J, Underreporting of viral encephalitis and viral meningitis, Ireland, 2005–2008. Emerg Infect Dis. 2013;19:142836 . DOIPubMedGoogle Scholar
  9. Bitnun  A, Richardson  SE. Childhood encephalitis in Canada in 2015. Can J Infect Dis Med Microbiol. 2015;26:6972 .PubMedGoogle Scholar
  10. Lindgren  E, Gustafson  R. Tick-borne encephalitis in Sweden and climate change. Lancet. 2001;358:168 . DOIPubMedGoogle Scholar
  11. Campbell  GL, Marfin  AA, Lanciotti  RS, Gubler  DJ. West Nile virus. Lancet. 2002;2:51929 . DOIPubMedGoogle Scholar
  12. Honnorat  E, De Broucker  T, Mailles  A, Stahl  JP. Le Comité de Pilotage et Groupe des Investigateurs. Encephalitis due to Mycobacterium tuberculosis in France. Med Mal Infect. 2013;43:2308 . DOIPubMedGoogle Scholar
  13. Government of Ontario. Infectious diseases protocol appendix A: disease-specific chapters. 2009 [cited 2015 Sep 1].
  14. Government of Ontario Ministry of Health and Long-Term Care. Appendix B: provincial case definitions for reportable diseases. 2009 [cited 2015 Sep 1].
  15. Granerod  J. Encephalitis in England: incidence and cause. London: London School of Hygiene and Tropical Medicine; 2011.
  16. Vora  NM, Holman  RC, Mehal  JM, Steiner  CA, Blanton  J, Sejvar  J. Burden of encephalitis-associated hospitalizations in the United States, 1998–2010. Neurology. 2014;82:44351 . DOIPubMedGoogle Scholar
  17. Granerod  J, Cousens  S, Davies  NWS, Crowcroft  NS, Thomas  SL. New estimates of incidence of encephalitis in England. Emerg Infect Dis. 2013;19:145562 . DOIPubMedGoogle Scholar
  18. Kwong  JC, Li  P, Redelmeier  DA. Influenza morbidity and mortality in elderly patients receiving statins: a cohort study. PLoS ONE. 2009;4:16. DOIGoogle Scholar
  19. Granerod  J, Crowcroft  NS. The epidemiology of acute encephalitis. Neuropsychol Rehabil. 2007;17:40628 . DOIPubMedGoogle Scholar
  20. Davison  KL, Crowcroft  NS, Ramsay  ME, Brown  DWG, Andrews  NJ. Viral encephalitis in England 1989–1999: what did we miss? Emerg Infect Dis. 2003;9:23440 . DOIPubMedGoogle Scholar

Main Article

1Current affiliation: Yale School of Public Health, New Haven, Connecticut, USA.

Page created: February 18, 2016
Page updated: February 18, 2016
Page reviewed: February 18, 2016
The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.