title: Challenges to the surveillance of meningococcal disease in an era of declining incidence in montréal, Québec.
abstract: OBJECTIVE
  Though rare in Montréal, meningococcal disease continues to cause serious morbidity and mortality. In an era of declining incidence, our objective was to evaluate the sensitivity and the timeliness of case reporting and the capacity to statistically detect disease clusters.
  
  
  METHODS
  We used the public health department's reportable disease database (RDD) to calculate the timeliness of reporting by physicians and laboratories for the period 1995 to 2008. The sensitivity of case reporting was evaluated through capture-recapture estimation using the RDD and the hospitalization discharge database (MED-ECHO). To evaluate the detection of cases clustered by time and proximity, we applied scan statistics to the RDD with cases coded by time and geographic location for the period 1992 to 2008.
  
  
  RESULTS
  While the system sensitivity was judged to be high at 94%, physicians reported only 54% of cases. A total of 92.3% of cases were notified by physicians or laboratories within seven days, meaning that in theory, 13 cases were not notified in time to conduct thorough contact tracing and offer chemoprophylaxis to close contacts. In high-incidence years, scan statistics detected two statistically-significant clusters one to two weeks earlier than traditional detection through the manual monitoring of cumulative cases.
  
  
  CONCLUSIONS
  To improve system performance, we recommended increasing the emphasis of laboratory reporting, reinforcing early reporting by physicians and if incidence increases, using scan statistics to identify clusters that can add to a public health practitioner's initial "hunch" of an emerging outbreak.
authors.affiliation: 1. Canadian Field Epidemiology Program, Public Health Agency of Canada, Ottawa, Ontario, Canada 2. Public Health Department, Montréal Health and Social Services Agency, Montréal, Québec, Canada. ruwan.ratnayake@rescue.org.
authors.forename: Ruwan
authors.initials: R
authors.lastname: Ratnayake
authors.forename: Robert
authors.initials: R
authors.lastname: Allard
mesh_terms: D016000:Cluster Analysis; D016208:Databases, Factual; D018563:Disease Notification / Q000706:statistics & numerical data*; D006801:Humans; D015994:Incidence; D007753:Laboratories; D008589:Meningococcal Infections / Q000453:epidemiology*; D011159:Population Surveillance / Q000379:methods*; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data; D011792:Quebec / Q000453:epidemiology; D013997:Time Factors
keywords: Disease clustering; Neisseria meningitidis; evaluation; public health; surveillance
references.citation: Lancet. 2007 Jun 30;369(9580):2196-2210
references.pmid: 17604802
references.citation: Public Health Rep. 2006 Mar-Apr;121(2):133-9
references.pmid: 16528945
references.citation: Can J Public Health. 1999 Jul-Aug;90(4):250-2
references.pmid: 10489722
references.citation: Can Commun Dis Rep. 1997 Feb 15;23(4):25-8
references.pmid: 9136225
references.citation: Epidemiology. 1995 Jan;6(1):42-8
references.pmid: 7888444
references.citation: Emerg Infect Dis. 2006 Nov;12(11):1689-95
references.pmid: 17283618
references.citation: Int J Epidemiol. 1991 Mar;20(1):290-2
references.pmid: 2066237
references.citation: MMWR Recomm Rep. 2005 May 27;54(RR-7):1-21
references.pmid: 15917737
references.citation: Epidemiol Infect. 2008 Aug;136(8):1088-95
references.pmid: 17892628
references.citation: Public Health. 2009 Dec;123(12):805-8
references.pmid: 19958917
references.citation: JAMA. 2004 Nov 24;292(20):2491-4
references.pmid: 15562128
references.citation: Can Commun Dis Rep. 2009 Apr;35(ACS-3):1-40
references.pmid: 19400026
references.citation: Epidemiol Rev. 1995;17(2):243-64
references.pmid: 8654510
references.citation: Can Commun Dis Rep. 2006 Sep 1;32(17):187-98
references.pmid: 16989044
references.citation: Bull World Health Organ. 1996;74(4):407-11
references.pmid: 8823963
references.citation: MMWR Morb Mortal Wkly Rep. 2010 Nov 19;59(45):1480-3
references.pmid: 21085089
references.citation: Am J Epidemiol. 1996 Jul 1;144(1):78-82
references.pmid: 8659488
references.citation: Clin Infect Dis. 1998 May;26(5):1159-64
references.pmid: 9597245
references.citation: Can Commun Dis Rep. 2000 May;26 Suppl 3:i-iv 1-122
references.pmid: 11055080