title: Epidemic of invasive pneumococcal disease, western Canada, 2005-2009.
abstract: In Canada before 2005, large outbreaks of pneumococcal disease, including invasive pneumococcal disease caused by serotype 5, were rare. Since then, an epidemic of serotype 5 invasive pneumococcal disease was reported: 52 cases during 2005, 393 during 2006, 457 during 2007, 104 during 2008, and 42 during in 2009. Of these 1,048 cases, 1,043 (99.5%) occurred in the western provinces of Canada. Median patient age was 41 years, and most (659 [59.3%]) patients were male. Most frequently representing serotype 5 cases (compared with a subset of persons with non-serotype 5 cases) were persons who were of First Nations heritage or homeless. Restriction fragment-length polymorphism typing indicated that the epidemic was caused by a single clone, which multilocus sequence typing identified as sequence type 289. Large pneumococcal epidemics might go unrecognized without surveillance programs to document fluctuations in serotype prevalence.
authors.affiliation: Provincial Laboratory for Public Health (Microbiology) Edmonton, Alberta, Canada. greg.tyrrell@albertahealthservices.ca
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Tyrrell
authors.forename: Marguerite
authors.initials: M
authors.lastname: Lovgren
authors.forename: Quazi
authors.initials: Q
authors.lastname: Ibrahim
authors.forename: Sipi
authors.initials: S
authors.lastname: Garg
authors.forename: Linda
authors.initials: L
authors.lastname: Chui
authors.forename: Tyler J
authors.initials: TJ
authors.lastname: Boone
authors.forename: Carol
authors.initials: C
authors.lastname: Mangan
authors.forename: David M
authors.initials: DM
authors.lastname: Patrick
authors.forename: Linda
authors.initials: L
authors.lastname: Hoang
authors.forename: Greg B
authors.initials: GB
authors.lastname: Horsman
authors.forename: Paul
authors.initials: P
authors.lastname: Van Caeseele
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Marrie
mesh_terms: D000328:Adult; D000368:Aged; D002170:Canada / Q000453:epidemiology; D058872:Epidemics; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D058885:Multilocus Sequence Typing; D011008:Pneumococcal Infections / Q000453:epidemiology*; D015995:Prevalence; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D055815:Young Adult