title: Characteristics of an Acanthamoeba keratitis outbreak in British Columbia between 2003 and 2007.
abstract: OBJECTIVE
  Quantify and describe Acanthamoeba keratitis (AK) cases in British Columbia (BC).
  
  
  METHODS
  A comparison of annual incidence rates confirms the presence of an outbreak. A case series describes characteristics of the outbreak.
  
  
  METHODS
  All laboratory-confirmed AK cases (persons) in BC (1988-2011; n = 68) were included in the incidence rate comparison. Of the 42 cases (persons) between 2003 and 2007, 32 were selected to interview (laboratory confirmed, 2005-2007), and the 23 who completed interviews form the case series.
  
  
  METHODS
  A comparison of standardized annual incidence rates in historic to outbreak periods is performed by z-score test. A telephone interview and descriptive analysis detailing demographics, risk factors, and contact lens (CL) wearing habits was completed for 23 cases.
  
  
  METHODS
  We measure number of laboratory confirmed cases in BC. In addition, risk factors and potential exposures of these cases are reported.
  
  
  RESULTS
  The annual incidence of AK increased significantly from 0.029 to 0.200 per 100 000 population between historic years (1988-2002) and outbreak years (2003-2007; P = 0.022). The annual incidence of AK has since returned to near historic levels (0.056/100 000 population). The case series identified multiple risk factors, including the use of a specific recalled solution (60.9%), daily soft CL wear (95.7%), all-in-one solutions (95.7%), showering while wearing CL (65.2%), and generally poor CL hygiene.
  
  
  CONCLUSIONS
  A significant increase in annual AK incidence occurred between 2003 and 2007 in BC. After 2007, the incidence of AK returned to near historic levels. The recalled solution was associated with many cases; however, other risk factors were also identified, including being unaware of the recall and poor CL hygiene practices, highlighting the need for improved education about the severity of AK and consequences of improper CL hygiene.
  
  
  BACKGROUND
  The authors have no proprietary or commercial interest in any of the materials discussed in this article.
authors.affiliation: British Columbia Centre for Disease Control, Epidemiology Services, Vancouver, British Columbia, Canada. Mieke.Fraser@bccdc.ca
authors.forename: Mieke N
authors.initials: MN
authors.lastname: Fraser
authors.forename: Quantine
authors.initials: Q
authors.lastname: Wong
authors.forename: Lena
authors.initials: L
authors.lastname: Shah
authors.forename: Simon P
authors.initials: SP
authors.lastname: Holland
authors.forename: Muhammad
authors.initials: M
authors.lastname: Morshed
authors.forename: Judith
authors.initials: J
authors.lastname: Isaac-Renton
authors.forename: Mei
authors.initials: M
authors.lastname: Chong
authors.forename: Pamela
authors.initials: P
authors.lastname: Kibsey
authors.forename: David M
authors.initials: DM
authors.lastname: Patrick
mesh_terms: D015823:Acanthamoeba Keratitis / Q000453:epidemiology*; D000293:Adolescent; D000328:Adult; D001955:British Columbia / Q000453:epidemiology; D002648:Child; D003263:Contact Lenses, Hydrophilic / Q000469:parasitology; D004196:Disease Outbreaks; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D012307:Risk Factors