Accuracy of prospective space-time surveillance in detecting tuberculosis transmission

Spat Spatiotemporal Epidemiol. 2014 Apr:8:47-54. doi: 10.1016/j.sste.2014.01.003. Epub 2014 Jan 23.

Abstract

To improve detection of tuberculosis transmission, public health can supplement contact tracing with space-time surveillance. However, investigation of space-time clusters not due to transmission (false alarms), may lead to costly, unnecessary interventions. We measured the accuracy of prospective space-time surveillance in detecting tuberculosis transmission, assessing the number of clusters containing transmission and the false alarm rate. We simulated monthly prospective applications of a scan statistic using the home addresses and diagnosis dates of all 1566 culture-positive TB cases reported in Montreal during 1996-2007. We verified transmission within the space-time clusters by analyzing the TB genotype. Over 11.5 years, at 1.3 false alarms per month, we detected 89 transmission chains; at 0.05 false alarms per month we detected 5 transmission chains. We found evidence that prospective space-time surveillance for TB leads to a high false alarm rate, limiting its practical utility in settings with TB epidemiology similar to Montreal.

Keywords: Prospective surveillance; Space–time clustering; Tuberculosis.

MeSH terms

  • Canada / epidemiology
  • Communicable Disease Control / methods
  • Communicable Disease Control / statistics & numerical data
  • Contact Tracing* / methods
  • Contact Tracing* / statistics & numerical data
  • Dimensional Measurement Accuracy
  • Genotyping Techniques
  • Humans
  • Models, Statistical
  • Mycobacterium tuberculosis* / genetics
  • Mycobacterium tuberculosis* / isolation & purification
  • Needs Assessment
  • Public Health Surveillance
  • Space-Time Clustering
  • Spatio-Temporal Analysis
  • Tuberculosis* / diagnosis
  • Tuberculosis* / epidemiology
  • Tuberculosis* / prevention & control
  • Tuberculosis* / transmission