Tuberculosis in the Northwest Territories, Canada: A Fourteen-Year Review (2000-2013)
The Northwest Territories (NWT) has one of the highest rates of tuberculosis (TB) in Canada, with a 2011 incidence of 29.8 per 100,000, compared to the Canadian average of 4.7 per 100,000. Furthermore, latent tuberculosis infection (LTBI), a condition in which infected persons do not exhibit evidence of clinically active disease, continues to be a significant concern in this population. The goal of this study is to describe the epidemiology of TB and LTBI in the NWT from 2000 to 2013.
METHODS: The study period was January 1, 2000 to December 31, 2013. Patient data were extracted from the Integrated Public Health Information System (iPHIS). Immunization records and cancer statistics were linked using the NWT Immunization Registry and NWT Cancer Registry, respectively. Population data were obtained from the 2011 Canadian Census. All descriptive data analyses were conducted using SPSS and Microsoft Excel.
RESULTS: Preliminary descriptive analyses indicate that 136 active cases of TB were diagnosed between 2000 and 2013, giving an average annual incidence rate of 23.4 per 100,000 population. Sixteen cases (12%) were retreatment cases. Respiratory TB was the major disease site, representing 72% of active cases. The majority of active cases were male (63%), and of Aboriginal descent (88%). About a third of cases (n=44) were 60 years or older, 10% of cases were aged 0 to 19 years, and 58% were aged 20 to 59 years at the time of diagnosis.
CONCLUSIONS: Further analyses concerning the annual risk of infection, risk factors, BCG coverage, and tuberculin skin tests are pending. The results from this study will be used to review the NWT TB program and surveillance system, to develop a reporting tool to inform public health practitioners at the frontline, and to provide epidemiological evidence to support the development of an LTBI treatment strategy.