Many people have this bacterium inside their body but most of them do not have a manifest infection. Once the immune system is weakened the bacteria becomes active and so symptoms of the disease appear.

Not everyone develops this affection. The people at risk are those who have no homes, who live in crowded and unsanitary conditions, who were in prison, and who use drugs. The most affected ones are those who live in developing countries as the sanitary system in those countries is not well adjusted yet.

Tuberculosis is a disease which affects mostly the lungs but can also affect the kidneys, the brain, the bones and he joints. In most people tuberculosis is inactive but in those who have a weakened immune system like in the HIV patients tuberculosis becomes active and manifests.

Tuberculosis can be caught by air, if an infected person coughs or sneezes and spreads the bacteria in small droplets of saliva. Shaking hands or using the same tools when working does not give you the infection because the bacteria dies fast if exposed to sun and air and survives only if inhaled in the lungs.

In most of the cases if the bacteria gets into the lungs the immune system will stop it from dividing and so the bacteria will remain in an inactive state inside the lungs. These people have no symptoms and they can be discovered as carriers of the disease only by a special skin test.

5% of those who get infected will develop the primary pulmonary tuberculosis. These patients are mostly children and HIV patients who have a weakened immune system and that is why they can not fight against this disease when they get infected.

95% of those who get infected will develop the disease only after several years as their immune system is able to inactivate the disease for a while. The disease will manifest when the immune system will be too weak to fight the bacteria and so the lungs will be affected, and cavities filled with bacteria and dead cells will appear inside them.

The extra pulmonary tuberculosis refers at those cases in which tuberculosis had affected other organs besides the lungs, like the liver, the kidneys and the bones.

The military tuberculosis is the form of the disease which spreads by the bloodstream towards the entire organism.

The way to show if someone is positive, meaning that it is infected but it has no symptoms is to take a PPD skin test.

In primary tuberculosis cases the symptoms which appear are fever and fatigue mostly but cough, night sweats, and chest pains are present.

In post primary tuberculosis patients symptoms vary from fever, cough and night sweats to weakness and loss of weight. In some cases coughing with blood can appear and problems with breathing can interfere.

In extra pulmonary tuberculosis patients the symptoms vary due to the location of the disease. If the lymph nodes are affected than they might become swollen; in the disease is located in the bones and joints than the spine, knees and joist might become painful.

In the military tuberculosis symptoms vary from fever, loss of weight, cough and night sweats to headaches, skin rashes, and visual problems.