A Health Surveillance Update on Canadian Children and Youth

Tuberculosis

Although the current tuberculosis incidence in Canada is quite low compared to other countries, regional differences exist and certain groups are at increased risk for this disease.

Worldwide, tuberculosis (TB) is the leading cause of death due to a single infectious agent.⁽¹³⁾ After decades of declining rates, the reported incidence of TB in Canada has levelled off since 1987.⁽¹⁴⁾ The emergence of drug-resistant TB strains, the interaction with HIV/AIDS and the increase in population movements around the world due to travel, trade and migration have greatly increased the potential for a resurgence of this disease in Canada. Although the current overall TB incidence for Canada is quite low compared with other countries, there are regional differences, and certain groups are at increased risk for this disease. They include disadvantaged inner city residents, such as the homeless, Aboriginal Peoples and individuals who have come from regions of the world where the disease is much more prevalent.⁽¹⁵⁾ Children belonging to these groups share this increased risk. TB cases are reported from the local level to the provincial and territorial health authorities and, since 1996, subsequently to the Division of Tuberculosis Prevention and Control, Bureau of HIV/AIDS, STD and TB, LCDC. The tuberculosis incidence rate is the number of reported new active or relapsed cases of tuberculosis per 100,000 persons per year.

In Canada in 1996, there were 204 cases of TB diagnosed in children and youth aged 0 -19 years. Of these cases, 108 occurred in children less than 10 years of age, and the remaining 96 cases occurred in those aged 10 -19 years. Of the 203 cases reporting background information, 82 or 40.4% occurred in children born outside of Canada. An additional 85 or 41.9% occurred in Aboriginal children and youth, including Status Indians, non-Status Indians, Metis and Inuit children.

An examination of the proportion of Canadian TB cases occurring in children and youth also reveals notable differences between sub-populations in Canada. The 204 cases of TB in children and youth in Canada represent 11% of the total number of Canadian TB cases in 1996. However, among Status Indian and non-Status Indian/Metis, the proportion of TB cases occurring in children and youth is 32.1% and 25.5% respectively.

As depicted in Figure 5 the reported TB incidence among children and youth has been relatively steady since 1991 though 1996 of 2.6 per 100 population is lower than recent years.

Source: Bureau of HIV/AIDS, STD and TB, LCDC⁽¹⁵⁾

There is great variation in TB notification rates among nations. The availability of international comparisons of TB rates among children is limited. However, a comparison of overall TB rates in different countries provides valuable information on the burden of disease. Countries in Asia and Africa are particularly affected by TB.⁽¹⁶⁾ In contrast to the 1996 Canadian TB incidence of 6.2 per 100,000, the World Health Organization estimates for 1996 for Nigeria and India are 222 and 220 per 100,000 respectively. Figure 6 presents the 1996 TB incidence for Canada and selected developed countries.^(17-19)

Source: Bureau of HIV/AIDS, STD and TB, LCDC^(15,17-19)

Data limitations
The TB data collected and reported in Canada are very reliable. International comparisons may be limited by variations in case detection and reporting practices in different countries.

Summary
Although the burden of TB has declined dramatically in Canada since the middle of this century, the potential for a resurgence in this country exists. Ongoing efforts to address TB in high-risk populations in Canada, in addition to global TB control strategies, are required. The success of these control strategies may be assessed in part through accurate national TB surveillance, including the surveillance of TB in Canadian children and youth.

Unless referenced otherwise, tuberculosis statistics are the product of the Bureau of HIV/AIDS, STD and TB, LCDC⁽¹⁵⁾

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