title: The epidemiology of invasive disease due to Haemophilus influenzae serotype a in the Canadian North from 2000 to 2010.
abstract: BACKGROUND
  The International Circumpolar Surveillance (ICS) project is a population-based surveillance network. Since 2000, Canada has participated in the ICS Invasive Bacterial Disease Working Group's surveillance of invasive disease due to Haemophilus influenzae (Hi).
  
  
  METHODS
  A standardized case report form containing demographic and clinical information was completed for all reported Hi cases in the study regions. Isolates were sent to a reference laboratory for confirmation and serotyping. Analysis was conducted on all Hi serotype a (Hia) cases reported from 2000 to 2010. The northern Canadian population was estimated using Statistics Canada information.
  
  
  RESULTS
  Of the 130 Hi cases reported from 2000 to 2010, 72 (56% of cases with serotype information) were due to Hia. The number of Hia cases reported each year ranged from 2 in 2008 to 13 in 2010. The average Hia incidence over the 11 years was 4.6 cases per 100,000 population per year. The majority of Hia occurred in infants less than 2 years of age (73% of cases). This age group had an average annual incidence of 87.5 cases per 100,000 population. Among cases for which ethnicity was indicated, 91% of Hia cases reported Aboriginal status with the average incidence being 6.9 cases per 100,000 population per year. The most common clinical presentation was meningitis (reported in 37% of cases), followed by bacteraemia (34%) and pneumonia (27%). More than 90% of cases were hospitalized, and there were 4 deaths, resulting in a case fatality ratio of 5.6%.
  
  
  CONCLUSIONS
  In the last decade, Hia has become an important cause of morbidity and mortality in the Canadian North. More detailed surveillance information from a national perspective is needed. Further work on vaccine development should be encouraged.
authors.affiliation: Centre for Immunization and Respiratory Infectious Diseases, Public Health Agency of Canada, Ottawa, Ontario, Canada.
authors.forename: Jenny L
authors.initials: JL
authors.lastname: Rotondo
authors.affiliation: Centre for Immunization and Respiratory Infectious Diseases, Public Health Agency of Canada, Ottawa, Ontario, Canada.
authors.forename: Lindsey
authors.initials: L
authors.lastname: Sherrard
authors.affiliation: Centre for Immunization and Respiratory Infectious Diseases, Public Health Agency of Canada, Ottawa, Ontario, Canada.
authors.forename: Melissa
authors.initials: M
authors.lastname: Helferty
authors.affiliation: Syphilis Diagnostics and Vaccine Preventable Bacterial Diseases, National Microbiology Laboratory, Public Health Agency of Canada, Ottawa, Ontario, Canada.
authors.forename: Raymond
authors.initials: R
authors.lastname: Tsang
authors.affiliation: Centre for Immunization and Respiratory Infectious Diseases, Public Health Agency of Canada, Ottawa, Ontario, Canada.
authors.forename: Shalini
authors.initials: S
authors.lastname: Desai
mesh_terms: D000293:Adolescent; D000328:Adult; D001110:Arctic Regions / Q000453:epidemiology; D016470:Bacteremia / Q000453:epidemiology* / Q000382:microbiology / Q000503:physiopathology; D002170:Canada / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D021821:Communicable Diseases, Emerging / Q000453:epidemiology* / Q000382:microbiology; D004196:Disease Outbreaks; D005260:Female; D006192:Haemophilus Infections / Q000175:diagnosis / Q000453:epidemiology*; D006193:Haemophilus influenzae / Q000145:classification / Q000302:isolation & purification*; D006306:Health Surveys; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D012189:Retrospective Studies; D018570:Risk Assessment; D012703:Serotyping
keywords: Aboriginal; Arctic; Haemophilus influenzae; Hia; Northern Canada; emerging infections; infectious diseases; invasive bacterial diseases; surveillance