This disease, most commonly a problem among people who live in developing countries, is a bacterial infection that usually attacks the lungs. It can also affect other parts of the body, such as the brain, spinal cord and kidneys. A full-blown, active case of tuberculosis can be deadly.


Tuberculosis is caused by a bacterium called Mycobacterium tuberculosis. It can be transmitted when a person with an active infection coughs, sneezes or speaks. The bacteria become airborne and can be breathed in by another person. This can cause a new infection. Tuberculosis is not transmitted by shaking an infected person's hand, by sharing food or drink, or by kissing. It does not spread through bed linens or toilet seats.

Latent TB Infection

Tuberculosis has two forms. The first, called latent TB infection, occurs when a person is infected with the bacteria, but their immune system is able to fight the infection successfully. People with latent TB do not have any symptoms. They do not feel sick, and they are not contagious. However, they may develop an active case in the future.

Active TB Infection

Active TB infection occurs when a person becomes infected and the immune system cannot keep the bacteria from growing. An active TB infection can cause a long-lasting, bad cough. The cough may produce blood or sputum. It may cause chest pain, weakness, and fatigue. The person may experience loss of appetite, weight loss, chills, fever, and night sweats.


A person who is diagnosed with latent TB may be treated with one medication or with a combination of medications over a period of months. A person diagnosed with active TB is treated with several medications for a period of 6 months to one year.