Nearly one-third of the world's population is infected with the bacteria that cause tuberculosis, which is why tuberculosis remains one of the most deadly diseases, according to the Centers for Disease Control and Prevention (CDC). The CDC reports that tuberculosis is responsible for approximately 2 million deaths worldwide every year, making it one of the world's most deadly diseases.
Cause
Tuberculosis is caused by infection with Mycobacterium tuberculosis, a large rod-shaped bacterium. Mycobacterium tuberculosis can infect many parts of the body including the skin, joints, bones, lymph nodes, kidney, spine and nervous system, but because these bacteria require oxygen in order to grow, they most often infect the upper portion of the lungs.
Transmission
Tuberculosis is highly contagious and spreads from person to person through the air. When a person infected with Mycobacterium tuberculosis talks, sings, coughs or sneezes, tiny droplets containing the bacteria are released into the air to be inhaled by anyone standing nearby.
Risk Factors
Although tuberculosis can infect anyone, there are certain groups of people who are at a higher risk of being infected with the Mycobacterium tuberculosis. Any person who has had close contact with someone suffering from an active tuberculosis infection is at an increased risk.
If you have a weakened immune system caused by another illness such as AIDS, your risk of contracting an active tuberculosis infection is increased. In these cases tuberculosis may become active disease within weeks of being infected.
Those who work or live in an institutional type facility, such as a hospital, nursing home, prison or homeless shelter are at an increased risk of contracting tuberculosis. This is due to the fact that the infection easily spreads from person to person and in close living quarters.
Latent Infection
The majority of people who become infected with the tuberculosis bacteria will not develop tuberculosis disease, according to the CDC. In healthy individuals, once the bacteria enter the body, the immune system fights the bacteria inhibiting them from growing and causing the bacteria to become dormant. Those with a latent infection do not have any signs or symptoms, cannot spread tuberculosis but will test positive for a TB skin test and should receive treatment to prevent the latent infection from becoming active.
Disease
Approximately 10 percent of the latent tuberculosis infections will become active disease, according to an article published in the Canadian Medical Association Journal. When your immune system can no longer keep the bacteria from growing and multiplying, they become active, causing tuberculosis disease. Patients with active tuberculosis disease will exhibit symptoms including a cough that lasts for 3 weeks or longer, chest pain and coughing up bloody sputum. Those with tuberculosis disease are highly contagious and can spread the bacteria to those close to them.
