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Active Tuberculosis (TB)

Case Definition

Confirmed Case

  • Isolation by culture of Mycobacterium tuberculosis complex from a clinical specimen, specifically for M. tuberculosis, M. africanum, M. canetti, M. caprae, M. microti, M. pinnipedii, or M. bovis (excluding M. bovis BCG strain);

  • In the absence of confirmation by culture, active tuberculosis can be diagnosed clinically by: 
        -chest x-ray changes compatible with active tuberculosis; OR
        -clinical symptoms and/or signs of non-respiratory                               tuberculosis [1]; OR
        -histopathologic or post-mortem evidence of active                             tuberculosis; OR
        -favorable response to the therapeutic trial of anti-                               tuberculosis drugs.

Re-treatment Exclusion

A re-treatment case of tuberculosis is a case that has both current active tuberculosis and historic documentation of previously active tuberculosis.  If re-treatment commences within 6 months after the end of treatment for previously active tuberculosis, this re-treatment case is not counted as a new case of active tuberculosis.  This is consistent with the Public Health Agency of Canada case definition of re-treatment.

  1. Tuberculosis can occur anywhere in the body such as meninges (the connective tissue covering the brain and spinal cord), bone, kidney, or peripheral lymph nodes (small nodules that are part of the body's immune system).
Further Information

For more information on the case definition of active tuberculosis, please refer to the Technical Appendix of the annual TB surveillance reports  

SOURCE: Active Tuberculosis (TB) ( )
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