What is tuberculosis (TB)?

Tuberculosis (TB) is an infectious disease caused by a type of bacteria called Mycobacterium tuberculosis. TB most  commonly affects the lungs, when it is called pulmonary tuberculosis, but also can involve any other organ of the body in which case it is called extra-pulmonary tuberculosis. These FAQs are about pulmonary TB.   Frequently Asked Questions about Tuberculosis. (2013). [ebook] New Delhi-110002, India: Regional Office for South-East Asia, World Health Organization. Available at: http://www.searo.who.int/about/administration_structure/cds/ en/index.html [Accessed 1 Jan. 2018].

What are the symptoms of pulmonary TB?

The most common symptoms of TB are:
  • chronic cough
  • fever, especially rising in the evening
  • night sweats
  • chest pain
  • weight loss
  • loss of appetite
  • coughing up blood.

How does a person get TB?

TB is spread primarily from person to person through infected air during close contact. The bacteria get into the air when someone infected with TB of the lung coughs, sneezes, shouts, or spits. A person can become infected when they inhale minute particles of the infected sputum from the air. It is not possible to get TB by just touching the clothes or shaking the hand of someone who is infected.

TB germs spread more easily in crowded conditions as the bacteria sometimes stay alive in the air for a few hours, especially in small closed places with no fresh air. Fresh air scatters the germs and sunlight acts as a bactericide, killing the TB organisms. Exposure to moderately hot temperatures for extended periods of time is sufficient to kill these bacteria. Extra-pulmonary TB does not spread from person to person.

What is TB infection?

When a person breathes in the TB bacteria, in most cases, the body is able to fight them to stop them from growing. The bacteria become inactive, but do not die. They lie latent, and can become active later. This state is called TB infection. People who are infected with TB do not feel sick, do not have any symptoms, and cannot spread the disease. But they could develop TB disease at some time in the future.

Frequently Asked Questions about Tuberculosis. (2013). [ebook] New Delhi-110002, India: Regional Office for South-East Asia, World Health Organization. Available at: http://www.searo.who.int/about/administration_structure/cds/ en/index.html [Accessed 1 Jan. 2018].