March 24 is the World Health Organization’s World Tuberculosis Day.  On this day in 1882, Dr. Robert Koch announced his discovery of the cause of tuberculosis (TB): the TB bacteria. World TB Day reminds us that TB remains an uncontrolled epidemic in many parts of the world.

It is estimated that one third of the world’s population is infected with the TB bacteria. In 2005, there were almost 9 million new cases of tuberculosis globally. Effective cures have been available for decades, yet TB remains a leading infectious disease, killing up to 1.6 million people each year.

Since 2003, the annual incidence rate of TB in Canada has remained essentially stable with approximately 1,600 new and relapsed cases reported annually.  Certain population groups in Canada are disproportionately affected by tuberculosis. These include: foreign-born individuals from countries with a high incidence of TB, Aboriginal peoples, HIV infected individuals and those who have spent time in a correctional facility.

The international emergence of drug resistant strains of TB, seriously threatens global prevention and control efforts.  Multidrug-resistant and extensively drug-resistant TB has not yet been identified as a major problem in Canada; however, with the speed and ease of international travel, it is increasingly apparent that TB anywhere is TB everywhere.  To this end, the Public Health Agency of Canada continues to monitor and respond to these emerging threats.

MDR-TB, or multidrug-resistant TB, is a special form of drug resistant TB. MDR-TB is resistant to at least isoniazid and rifampin, the two most powerful anti-TB drugs.

Extensively drug-resistant TB (XDR-TB) is resistant to isoniazid and rifampin, any fluoroquinolone and at least one of three injectable second-line drugs (capreomycin, kanamycin and amikacin). XDR-TB is a growing international concern. In Canada, the incidence of MDR-TB remains low and XDR-TB rates are very low. Three cases of XDR-TB have been reported with one each in 2003, 2006 and 2008.

Federal, provincial and territorial governments and health professional organizations are working collaboratively to reduce the incidence rate of tuberculosis in Canada from 5.0 per 100,000 in 2006 to 3.6 per 100,000 by 2015.  The 2006-2015 Global Plan is to reduce the burden of the disease by 50 per cent compared to the 1990 rate, which requires a three per cent annual reduction in the incidence rate.