Tuberculosis in Canada 2002: Executive Summary

In 2002, 1,634 cases (5.2 per 100,000) of new active and relapsed TB were reported to the Canadian Tuberculosis Reporting System (CTBRS). The highest rate of 93.4 per 100,000 was reported from Nunavut and the lowest of < 1.0 per 100,000 from Nova Scotia. The three most populous provinces (British Columbia, Ontario and Quebec), which collectively make up 75% of Canada's population, accounted for 77% of the total reported cases.

By age group, individuals between the ages of 25 and 34 years made up the largest number of reported cases, accounting for 19% of the total. However, the corresponding case rate of 6.9 per 100,000 for this age group was surpassed by the age-specific rates of 9.3 and 11.8 per 100,000 for those in the older age groups of 65 to 74 years and > 74 years, respectively.

Accurate information on country of origin of TB cases in Canada has been available since 1970. In 2002, TB among foreign-born individuals accounted for 67% of all reported cases in Canada. Canadian-born Aboriginal cases represented 15% of the total cases reported; Canadian-born non-Aboriginal individuals accounted for 16%. Birthplace was unknown for 3% of cases.

Respiratory TB was the most frequently reported main diagnostic site, representing 64% of reported cases in 2002; however, diagnostic site varied by birthplace. TB of the peripheral lymph nodes was the second most commonly reported diagnostic site (14%), with 38% of these cases occurring in foreign-born individuals who originated in the World Health Organization (WHO) Western Pacific region. Primary TB accounted for 5% of reported cases and was more common among Canadian-born Aboriginals.

The number of laboratory-confirmed cases was 1,594 of the total cases (98%); 1,278 (78%) of the total cases were culture positive. Of these, 1,132 (89%) had no resistance to first-line TB drugs. Eight percent were resistant to one drug and the remaining 3% showed patterns of resistance to two or more drugs prescribed. The most common type of mono-resistance was to isoniazid (INH) accounting for 38% of all reported resistance. Multi-drug resistant TB (defined as resistance to at least INH and rifampin) accounted for 1.6% of the drug-resistant cultures reported.

Of the 1,702 cases diagnosed in 2001, 809 had a treatment outcome report, and 643 of these cases (79%) were reported as being culture negative or having completed treatment. An average of 84% of laboratory-confirmed pulmonary cases were cured or completed treatment. The vast majority of individuals placed on TB drug therapy in Canada received treatment as per the Canadian Tuberculosis Standards⁽¹⁾. Eighty-nine percent of these cases received three or more anti-tuberculosis drugs.

The total number of reported cases of TB in Canada has shown a continual decrease over the past decade. However, this decrease is mostly a reflection of a decreasing number of cases in the Canadian-born non-Aboriginal population. Cases in the Canadian-born Aboriginal population have shown a minimal decrease, whereas cases in the foreign-born population have remained relatively constant. In order to increase the annual rate of decline of new cases from 2.1% observed for the past 10 years to a national goal of 5%, considerable additional effort will be required, including the development and implementation of a Canadian Tuberculosis Prevention and Control Strategy.

Reference

1. Long R, ed. Canadian tuberculosis standards. 5th edition. Ottawa: Canadian Lung Association and Health Canada, 2000.