In 2012, ~8,600,000 people developed TB, and 1,300,000 died from the disease
TB mortality rates have dropped by 45% since 1990
22 countries account for 80% of all cases
Treatment is inexpensive, from a first-world perspective: ~$10/person
~13% of those with TB are HIV positive; Most (~74%) in Africa
Men are particularly at risk for the disease
Multi-drug resistant TB is an emerging global concern
Cause of Tuberculosis
Historically, TB was blamed on:
‘Evil air’ – a variation on the miasmatic explanation
Contagion spread through the breath
An act of God
TB is caused by Mycobacterium tuberculosis (identifed by Koch)
It is related to the zoonotic infection M. Bovis
There is evidence that TB is a very ancient disease; the current variant likely emerged with the
domestication of cattle, 4,000-8,000 years ago
TB is a disease of the lungs (it can also affect the spine, kidneys, and brain)
It is passed person-to-person via droplet transmission
Lungs are damaged by the inflammatory response to infection, causing damage to lung capillaries and
progressive loss of alveoli, which impairs lung capacity
Two forms:
Latent TB
Active TB
Night sweats
Chest pain
Coughing (which may involve blood or sputum)
Weight loss and loss of appetite
Risk factors for TB
Very young or old age
Substance abuse
Diabetes mellitus
Cancer of the head or neck
Leukemia or Hodgkin’s disease
Severe kidney disease
Low body weight
Some medical treatments (involving immunosuppressant drugs)
Living in poverty
Inadequate nutrition
Contaminated water
Poorly ventilated housing
Tuberculosis in History
Late 19th century
The rich sought out homes or vacations in warm, arid climates
20th century
TB sanatoria
Emerging drug resistance:
Inconsistent application of treatment
Inappropriate medications for specific strains
Inequality based on sexism, racism, lack of health care for poor
A popular attitude in West: Poor nations are overpopulated and non-compliant – why bother?