Tuberculosis, also called TB, is an infection caused by a bacteria (a germ). Tuberculosis usually affects the lungs, but it can spread to the kidneys, bones, spine, brain and other parts of the body. The disease tuberculosis is caused by the bacteria Mycobacterium tuberculosis. It is important to understand that there is a difference between being infected with TB and having TB disease. Someone who is infected with TB has the TB germs, or bacteria, in their body. The body's defenses are protecting them from the germs and they are not sick.

Someone with TB disease is sick and can spread the disease to other people. A person with TB disease needs to see a doctor as soon as possible.

It is not easy to become infected with tuberculosis. Usually a person has to be close to someone with TB disease for a long period of time. TB is usually spread between family members, close friends, and people who work or live together. TB is spread most easily in closed spaces over a long period of time. However, transmission in an airplane, although rare, has been documented.

Tuberculosis can affect any part of the body but usually infects the lungs. Tuberculosis is spread through airborne droplets occurring when an infected individual sneezes, talks, or coughs. However, prolonged exposure to the infected individual must occur before you may become infected. The body may harbor the bacteria while the immune system prevents sickness. For this reason, there are two forms of TB: latent tuberculosis and active tuberculosis.

With latent tuberculosis, the immune system is able to prevent the bacteria from growing. The tuberculosis bacteria remain alive within the body but are inactive at this time. However, the bacteria can become active later in life. Those with latent tuberculosis have no symptoms, do not feel sick, are not contagious, and may develop TB later in life if they do not receive treatment.

Active tuberculosis simply means that the tuberculosis bacteria are growing within the body causing an active infection. Signs and symptoms of active tuberculosis include fatigue, slight fever, chills, night sweats, loss of appetite, unintended weight loss, a cough that lasts three or more weeks producing discolored or bloody sputum, and pain with coughing or breathing. Active tuberculosis is highly contagious.

A person with tuberculosis infection may not have any symptoms.

Tuberculosis infection is diagnosed by a skin test. Although there is more than one TB skin test, the preferred method of testing is to use the Mantoux test.3

For this test, a small amount of testing material is placed just below the top layers of skin, usually on the arm. Two to three days later a health care worker checks the arm to see if a bump has developed and measures the size of the bump. The significance of the size of the bump is determined in conjunction with risk factors for tuberculosis.

Once the doctor knows that a person has tuberculosis infection he or she will want to determine if the person has tuberculosis disease. This is done by using several other tests including a chest X-ray and a test of a person's mucus (the material that is sometimes coughed up from the lungs).

The advice for most people is to get a tuberculin test if you have symptoms or if you are living in close contact or have otherwise been in close contact with someone who recently came down with tuberculosis disease. (Some people get skin tests because of their jobs, in a school or hospital, for example, to make sure they have not contracted tuberculosis and will not infect others if they have tuberculosis).

If you fall into one or more of the high-risk categories for tuberculosis noted earlier, for example, if you are HIV-positive, never had a skin test before, or there is no record of the last result, you should be tested.

If you're not sure, ask your doctor. tuberculosis can be prevented, even if you are at risk.

What is causing the tuberculosis pandemic?

Improved public health programs have helped to create a steady decline of tuberculosis cases in the United States. However, the problem is far from solved. Factors that contribute to the spread of tuberculosis in the U.S. and elsewhere include the increase in number of foreign born nationals, crowded living conditions, increase in drug resistant strains of tuberculosis, lack of access to medical care, and the increase in poverty.

Poorly ventilated and crowded conditions help to spread TB. This is one reason tuberculosis cases have reached epidemic proportions. Although the incidence of TB cases in the U.S. is declining, the incidence in other parts of the world is increasing. Half of the reported cases in the U.S. (in 2000) occurred in individuals that were born outside of the U.S. Individuals that live in poverty, move or migrate often usually do not finish the tuberculosis treatment. This is leading to drug resistant forms of tuberculosis.

Tuberculosis bacteria have developed strains of the bacteria that are resistant to each of the major tuberculosis medications. There are also strains of tuberculosis that are resistant to at least two tuberculosis medications. This multidrug-resistant TB (MDR-TB) is posing an even deadlier threat to those affected. Individuals affected with MDR-TB are much more difficult to treat requiring a long term therapy of up to two years. The medications required to treat these strains can cause serious side effects. This is one great reason to complete the entire course of medication as prescribed by your doctor.

An individual in an immunocompromised state is at risk of developing TB. A number of factors can cause the immune system to be in a weakened state. Some diseases can suppress the immunity such as diabetes <http://www.disabled-world.com/health/diabetes/>, HIV/AIDS, and silicosis. Certain medications can affect the body's immune system which includes chemotherapy drugs and corticosteroids. An increased risk of reactivated tuberculosis has been associated with the use of arthritis medications Enbrel and Remicade.

Individuals within close proximity of those infected with tuberculosis are at an increased risk of developing disease. Individuals in areas of high rates of tuberculosis (Asia, Africa, Latin America, former Soviet Union) have an increased risk of developing tuberculosis.

Certain races (Hispanics, American Indians, Asian Americans, African Americans) in the U.S. are at risk of developing tuberculosis. What other factors may increase your risk of developing tuberculosis?

The older adult is at an increased risk of developing tuberculosis due to a weakened immune system. Individuals who are malnourished, lack adequate medical care, or who suffer from long term drug or alcohol abuse are at increased risk of developing tuberculosis. Health care workers are at increased risk of developing tuberculosis also.

If you develop any of the signs or symptoms listed above, you should seek medical advice. Individuals with HIV and Aids <http://www.disabled-world.com/health/aids/> should be tested for tuberculosis, since the leading cause of death in the AIDS patient is tuberculosis. HIV and tuberculosis have a deadly symbiosis, in which TB increases the rate at which the AIDS virus replicates and HIV reactivates inactive TB. Health care workers are usually tested at least yearly for tuberculosis by Mantoux test. Individuals with latent tuberculosis reveal a positive Mantoux even though no symptoms of the disease are evident. Tuberculosis is also tested by chest x-ray and culture tests (urine, sputum).

There are a few measures one can take to protect their health. First, you should be tested regularly. If you have an immune suppressing disease, live or work in a prison or nursing home, were born in a TB prevalent country, or have other risk factors, then a Mantoux test should be done every six months.

If you test positive without symptoms, speak with your doctor about treatments to reduce the risk of developing active tuberculosis. The most important step you can do for the public and yourself is to finish the entire course of medication. Treatment that is stopped to early allows the bacteria a chance to mutate to a drug resistant form.