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What is TB?
• Tuberculosis is an infectious disease– Patient is sick, contagious– We call this ‘TB’
• Mycobacterium tuberculosis is name for the bacteria that causes TB
• Most infected people do not develop the disease– These people are not contagious– We call this ‘latent infection’
Clinical manifestations of TB
• General– Fever, weight loss, weakness– “Consumption”, “Phthisis”
• Organ specific– Lungs: cough, spitting up blood– Others:
• Scrofula: swollen lymph nodes• Spine: ‘hump-back’ • Etc.
Chest x-ray in pulmonary TB
Cavity represents collection of millions of bacteria that are transmitted by cough
TB is reason why X-rays are done with immigration
TB disease and infection: Natural History
Infection
Infection without disease – 90%
Person with active TB
TB disease and infection: Natural History
Infection
Progression to active TB disease - 10%
Infection without disease – 90%
Person with active TB
Preventive treatment: Isoniazid
Global epidemiology
• Tuberculosis disease– ~9 million new cases per year– 1.5 million deaths per year• Every 15 seconds
• Latent infection– 2 billion persons infected• One person infected each second
– If 10% progress, 200 million future cases
0 - 2425 - 4950 - 99100 - 299
No estimate300 or more
Estimated new TB cases (all forms) per 100 000 population
TB incidence per 100,000 people
Source: WHO
0 - 9991000 - 999910 000 – 99 999100 000 - 999 999
No estimate1 000 000 or more
Estimated number of new cases (all forms)
TB cases
Source: WHO
TB in Canada has declined to low levels, but it remains an important concern in immigrants
and Aboriginals
April 2011
Globally, incidence rates falling after peak in 2004, but only at <1%/year
Peak in 2004
Incidence (all forms, incl. PLHIV)
TB Notifications
Incidence TB in PLHIV
shaded area = uncertainty band
Notification gap
Courtesy: WHO Stop TB Department
http://www.worldcarecouncil.org
TB elimination is impossible with current tools
14
Diagnostic tools that Robert Koch used…
Microscopy Culture Tuberculin test
15
are still in use today!
• Active TB– Sputum microscopy [1882]– Mycobacterial culture [1882]– Chest X-rays [1896]
• Latent TB (LTBI)– Tuberculin skin test [1890]
We desperately need new TB vaccines and drugs
BCG: 1920s
Rifampin: 1950s
Host genetics and strain variations
New TB diagnostics
New TB drug regimens
Global health and TB
Modeling and cost-effectiveness
Social determinants
Statistical methods and approaches
Knowledge translation and policy
Sources of funding
Thank you!
