More than 1.7 billion people (about 25 percent of the world population) are estimated to be infected with M. tuberculosis

Latent disease believed to affect >20% of world population.

The greatest known risk factor for progression of latent infection to active tuberculosis is HIV infection.

Pulmonary:

• Cavitating pneumonia
• Upper lobe pnuemonia
• Occasionally miliary

Extrapulmonary:

• Lymph node disease
• CNS infection
• Osteomyelitis (Potts)
• Peritoneal
• Pericarditis
• Others