What is Tuberculosis
- Tuberculosis (TB) is an infectious disease caused by a special type of bacteria, called Mycobacterium tuberculosis. The bacilli or TB germs causing tuberculosis are also called ‘Tubercle‘ bacilli or ‘Acid Fast Bacilli’ (AFB) as they retain dye to appear as red rods (microscopically) after decolourization with acid and alcohol. The patient whose sputum sample shows these organisms (on staining) under the microscope is called a sputum positive (infectious) case.
- TB is spread through air as a droplet infection. When a diseased person coughs, sneezes or produces phlegm (sputum), the bacteria are released in the air. When a non-infected person is exposed to this air for a long time, he can become infected.
- Commonly known as pulmonary tuberculosis, the most common organ of the body to be affected is the lung. In the lung, the TB bacilli can cause destruction and result in a cavity formation. Though other organs can also be affected, they are generally less commonly affected than the lungs.
- If the spread of the disease is not checked, it can seriously affect the working of that particular organ, ultimately leading to total disruption of its functions, which may finally result in the death of the patient.
- If the disease is left untreated, after 5 years 50% of TB patients will be dead, 25% will stay healthy (due to strong immunity) and the rest (25%) will become chronic sputum positive cases.
- Tuberculosis is also known by many other names such as:
- King’s evil ( touching the king’s feet was supposed to cure TB)
- White plague
- Koch’s disease (after Robert Koch who discovered the bacteria causing TB)
The other parts of the body which can get affected include lymph nodes, meninges (covering surrounding the brain), peritoneum(the membrane covering the digestive organs), intestines, kidneys, bones and joints (extra – pulmonary TB).