World TB Day is March 24th
March 24th has been designated World TB Day in order to raise awareness and support for worldwide TB elimination efforts. This annual event commemorates the date in 1882 when Dr Robert Koch announced his discovery of Mycobacterium tuberculosis, the bacterium that causes TB. TB has not disappeared – worldwide it still kills approximately a million people a year.
Fortunately, the rates in the United States have declined steadily since the 1990s, after a brief resurgence. In 2015, 9,563 individuals were diagnosed with active TB in the US, of those 67 were in Kentucky and 3 were in the Lake Cumberland District. Local health departments are responsible for ensuring TB patients receive treatment and people who may have been in close contact with these individuals are identified and tested.
TB most commonly affects the lungs, but can also cause infection of any organ of the body. One can become infected with TB by sharing living spaces with individuals who have active TB disease and are contagious; coughing contaminates the air with TB particles which may be inhaled by another person, who becomes infected. This infection can remain dormant (latent) for years and is non-contagious, but it can become active when an individual’s immune system weakens as can occur with advancing age, chronic diseases such as diabetes, use of immunosuppressant medication for rheumatoid arthritis or other autoimmune diseases or for cancer. Smoking can also increase the risk of TB activation.
More than half of TB cases in the US occur in foreign born individuals, who come from countries where TB is still relatively common. Testing for latent TB infection can be done using the TB skin test or the new gamma interferon blood tests (brand names, QuantiFERON test and T-spot test). TB Control Programs in the US and the CDC recommend that newly infected persons (those with positive skin tests or interferon tests) receive preventive treatment in order to lower their life time risk of progression to active disease.