But people infected with TB will not necessarily get sick with the disease. The immune system walls off the TB bacilli which, protected by a thick waxy coat, can lie dormant for years. When someone's immune system is weakened, the chances of getting sick are much greater.
There are two stages of Tuberculosis which are known as Primary TB and Secondary TB. In primary TB, a person has become infected with the TB bacteria but often is not aware of it, since this stage of the disease does not produce noticeable symptoms. Primary TB is not contagious at this stage of its" life (MMR, 1999). Specific immune cells called Macrophages that detect and destroy foreign matter, ingest the TB bacteria and transport them up to the lymph nodes where they may be stored, destroyed, or multiplied ( JAMA, 1999). The worst case scenario would be the multiplication of the bacteria. If this happens, active primary tuberculosis will develop. Symptoms for this include coughing, night sweats, weight loss, and fever. Also, a chest x-ray may show shadows in the lung or fluid collection between the lung and it's lining. If the bacteria are stored, rather than destroyed, the immune cells and the bacteria form a mass known as granuloma or tubercle (MMR, 1999). In this stage the immune cells form a wall around inactive bacteria. As long as the immune systems stays strong, the TB bacteria will remain inactive. The tubercle gradually collects calcium deposits to form what is know as Ghon focus (MMR, 1999). These initial tubercles in the lung usually heal, leaving permanent scars that appear as shadows in a chest X-ray. In this initial stage of TB, the disease does not progress, but bacteria may remain dormant in the body for many years, and if the immune system becomes weakened for some reason, the tubercle may open releasing the bacteria, and the infection may develop into secondary TB.
In secondary TB, the formerly stored bacteria begin to multiply and destroy tissue in the lungs.
