Tuberculosis, also known as TB, is caused by an infection of tuberculosis bacteria, more specifically known as mycobacterium tuberculosis. The disease is spread by breathing in air containing droplets of infected saliva, or sputum, from an infected person. Such air droplets are commonly released when a person is coughing, sneezing, or even just talking. This is the ultimate cause of the disease, but there are many tuberculosis causes in the sense that there are various factors that make the disease easier to contract and spread. Such supplementary tuberculosis causes include the rising incidence of HIV/AIDS, which weakens a person's immune system making them more susceptible to TB infection, and poverty combined with a lack of health care in developing countries and parts of the developed world.
Tuberculosis causes a variety of symptoms, including fever, chills, chest pain, and a cough that produces sputum that is green, yellow, or bloody. A person infected with TB who displays these symptoms has active tuberculosis. However, many people infected with this disease do not have any symptoms. This is called inactive TB, or latent tuberculosis infection (LTBI). Only people with active TB are capable of spreading tuberculosis.
Many of what could be called the additional tuberculosis causes, meaning factors that increase the risk of contracting the disease, are tied to low socioeconomic status. Homelessness, substance abuse, and malnutrition all increase the risk of becoming infected with TB, mainly because they lead to a lower resistance to all types of infections. One is more likely to contract TB from someone one is in close contact with on a regular basis, for example at work, school, or home. This means that living in crowded conditions, such as in a slum or a prison facility, is another of the additional tuberculosis causes because it facilitates the spread of this disease. Working in health care can also increase the risk of contracting TB, because of the sometimes crowded conditions in health care facilities, and because of the close contact between staff and patients there.
By some estimates, approximately 2 billion people are carriers of TB worldwide, and 3 million die from the disease each year. Traveling to a country where there is a high rate of tuberculosis infection can be considered another one of the supplementary tuberculosis causes. Mexico, China, India, and parts of the former Soviet Union all have high rates of TB cases.
