Genotypic characterization of tuberculosis transmission within Toronto's under-housed population, 1997-2008.

ABSTRACT

Toronto has been the site of a recent extended tuberculosis (TB) outbreak in the homeless or under-housed population. Genotyping has identified a unique strain that continues to circulate within this population, with spread to individuals with no links to the shelter system, and anecdotally appears to progress rapidly from infection to active disease in some cases. The recent appearance and transmission of another unique strain was also identified, indicating that TB transmission continues to be a problem within the under-housed population. Enhanced surveillance utilizing molecular epidemiology is a useful tool to assist in TB control in vulnerable populations.