[Skip to Content]
Wirral University Hospital NHS Foundation Trust

What is Tuberculosis (TB)?

Tuberculosis (TB) is an infectious disease that is caused by a bacterium called Mycobacterium tuberculosis. TB primarily affects the lungs, but it can also affect any other organ or part of the body.

There are two types of TB. Active TB and Latent TB.

A person with ACTIVE TB will:

  • Feel ill
  • Have symptoms that may include:
    • A bad cough that lasts 3 weeks or longer
    • Pain in the chest
    • Coughing up blood or sputum
    • Weakness or fatigue
    • Weight loss
    • No appetite
    • Chills
    • Fever
    • Sweating at night
  • May spread TB to others.
  • Usually has a positive skin test.
  • May have an abnormal chest x-ray, or positive sputum smear or culture.

A person with LATENT TB will:

  • Not feel ill
  • Cannot spread TB to others
  • Usually has a positive skin test
  • Has a normal chest x-ray and sputum test.

The most common type of TB is in the lungs, known as pulmonary TB. Only TB of the lungs or throat can be infectious. TB can affect any part of the body including kidneys, brain or bones. This is called non-pulmonary TB – and is not infectious.