1 Montreal Chest Institute and McGill International TB Centre, and Department of Medicine, McGill University, Montreal, QC H4A 3S5, Canada; Department of Medicine, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico.
2 Montreal Chest Institute and McGill International TB Centre, and Department of Medicine, McGill University, Montreal, QC H4A 3S5, Canada; Department of Epidemiology, Biostatistics and Occupational Health, and Department of Medicine, McGill University, Montreal, QC H4A 3S5, Canada. Electronic address: dick.menzies@mcgill.ca.