Active tuberculosis among homeless persons, Toronto, Ontario, Canada, 1998-2007

Area of Science:

• Public Health
• Infectious Diseases Epidemiology

Background:

• Tuberculosis (TB) disproportionately affects vulnerable populations, including homeless individuals.
• While TB incidence is rising among foreign-born persons in Canadian cities, homeless populations remain at significant risk.

Purpose of the Study:

• To analyze trends in active tuberculosis (TB) among homeless individuals in Toronto from 1998 to 2007.
• To compare Canada-born and foreign-born homeless individuals with TB and assess temporal changes.

Main Methods:

• Retrospective study of all homeless individuals diagnosed with active TB in Toronto between 1998 and 2007.
• Comparison of demographic characteristics, disease presentation, and TB strain origins between Canada-born and foreign-born homeless individuals.

Main Results:

• A total of 91 homeless individuals had active TB, often presenting with advanced, contagious disease; 19% died within 12 months.
• The proportion of foreign-born individuals among homeless TB cases increased from 24% (1998-2002) to 39% (2003-2007).
• Over half (56%) of TB infections in foreign-born homeless individuals were caused by strains not previously circulating in Toronto's homeless population.

Conclusions:

• The increasing prevalence of foreign-born homeless individuals with TB, carrying potentially novel strains, highlights an escalating risk of introducing drug-resistant TB into the homeless shelter system.
• Public health strategies must address the unique challenges and risks associated with TB in this demographic.
• Further research is needed to monitor TB trends and implement targeted interventions within homeless populations.