The disease was called "consumption" in the past because of the way it would consume infected people from within.
- When a person becomes infected with TB, the bacteria in the lungs multiply causing pneumonia; the patient experiences chest pain and has a persistent cough which often brings up blood.
- In addition, lymph nodes near the heart and lungs become enlarged. As the bacteria try to spread to other parts of the body they are interrupted by the body's immune system.The immune system forms scar tissue or fibrosis around the bacterium, which helps fight the infection and prevents it from spreading within the body and to other people.
- If the bacteria manage to break through the scar tissue the disease returns to an active state; pneumoniadevelops and there is damage to kidneys, bones, and the meninges that line the spinal cord and brain.
TB is generally classified as being either latent or active.
Latent TB -
the bacteria are inactive but present in the body. The patient has no symptoms and is not contagious.
Active TB -
the bacteria are active and make the patient ill. Active TB is contagious.
TB is a major cause of illness and death worldwide, especially in Africa and Asia. Each year the disease kills almost 2 million people. The disease is also prevalent among people with HIV/AIDS.
Global tuberculosis campaign threatened by multi-drug resistance
What causes tuberculosis
Tuberculosis is ultimately caused by the Mycobacterium tuberculosis, a bacterium that is spread from person to person through airborne particles. Inhaling infected particles does not necessarily mean that a person becomes infected.
One of three things may happen when Mycobacterium tuberculosis enters the human body:
- The bacterium is destroyed because the body has a strong immune system.
- The bacterium enters the body and remains as latent TB infection. The patient has no symptoms and cannot transmit it to other people.
- The patient becomes ill with TB.