Excerpt: “Analysis of the distribution of TB among the Canadian population shows that the risks and impacts of MTB strains are not uniformly distributed within our boundaries. As a consequence, a national prevention and control program demands central coordination, monitoring and evaluation with each province and territory being responsible for developing and implementing control plans that are consistent with Canadian guidelines and protocols. The formal implementation of genotyping in epidemiological investigations in combination with surveillance data at the national and provincial levels could best provide a coherent approach to timely outbreak response and case management and strengthen the TB surveillance partnerships in Canada.”
Key Points:
The total number of reported cases of active tuberculosis (TB) in Canada averages approximately 1,600 newly active and retreatment cases annually, with the highest rate of TB in Aboriginal populations.
TB genotyping is a useful adjunct tool for TB surveillance and outbreak investigation, especially in cases where epidemiological data are inadequate or unavailable.
The traditional gold standard TB genotyping method had been “Restriction Fragment Length Polymorphism” (RFLP); however, it has now been replaced by the newer, more reliable method of “Mycobacterial Interspersed Repeat Units-Variable Number Tandem Repeats” (MIRUVNTR).
The National Reference Centre for Mycobacteriology, within the National Microbiology Laboratory of the Public Health Agency of Canada (PHAC), provides reference and diagnostic services as well as technical assistance (e.g. technology transfer and personnel training) to provincial TB laboratories.
An interactive TB genotyping reference database has been proposed for the national coordination of conventional and molecular epidemiology of TB. This proposal was endorsed by the Canadian Tuberculosis Committee (CTC).
There is currently no established selection criterion in Canada to determine which TB samples should be genotyped.
Surveillance data on TB cases and TB drug resistance patterns are collected and analyzed annually by PHAC. However, national TB reporting is hampered by the lack of in-depth case demographic and epidemiological information and inconsistency in the type of information collected.
