Why tb happens

The Centers for Disease Control and Prevention recommends that people who have an increased risk of tuberculosis be screened for latent TB infection. This recommendation includes people who:. Tuberculosis is caused by bacteria that spread from person to person through microscopic droplets released into the air. This can happen when someone with the untreated, active form of tuberculosis coughs, speaks, sneezes, spits, laughs or sings. Although tuberculosis is contagious, it's not easy to catch.

You're much more likely to get tuberculosis from someone you live or work with than from a stranger. Most people with active TB who've had appropriate drug treatment for at least two weeks are no longer contagious. HIV suppresses the immune system, making it difficult for the body to control TB bacteria.

Tuberculosis also remains a major killer because of the increase in drug-resistant strains. Over time, some TB germs have developed the ability to survive despite medications. This is partly because people don't take their drugs as directed or don't complete the course of treatment. Drug-resistant strains of tuberculosis emerge when an antibiotic fails to kill all of the bacteria it targets.

The surviving bacteria become resistant to that drug and often other antibiotics as well. Some TB bacteria have developed resistance to the most commonly used treatments, such as isoniazid and rifampin Rifadin, Rimactane. Some TB strains have also developed resistance to drugs less commonly used in TB treatment, such as the antibiotics known as fluoroquinolones, and injectable medications including amikacin and capreomycin Capastat.

These medications are often used to treat infections that are resistant to the more commonly used drugs. Children with TB or people with a TB infection that occurs outside the lungs extrapulmonary TB do not spread the infection. But in some cases, the bacteria infect the body but do not cause any symptoms latent TB , or the infection begins to cause symptoms within weeks, months or even years active TB.

This usually happens either within the first year or two of infection, or when the immune system is weakened — for example, if someone is having chemotherapy treatment for cancer.

Then they become infected. Once you breathe in the bacteria, they settle in your lungs and begin to grow. Sometimes the bacteria move from the lungs to other areas of the body. This could include the kidneys, spine, and brain. This means you can spread the disease to other people. Usually, you have to be in close contact with someone who has active TB.

You need to be around them for an extended period of time. TB tends to be spread between family members, close friends, and people who live or work together. This could include:. The most commonly used method to check for tuberculosis is a skin test. Blood tests can also be used. If you have a positive skin test or blood test, it means you have been exposed to a person who has tuberculosis. You have been infected with the bacteria that cause the disease.

If your skin test is positive, you will likely have a chest X-ray and a physical exam. This will tell your doctor which kind of TB you have. Usually, a person can be infected with the bacteria that cause TB but not actually have active tuberculosis. The best way to prevent getting a tuberculosis infection is to avoid being in close contact with a person who has active TB disease. There is a vaccine against tuberculosis.

Tuberculosis is treated with antibiotic medicine. The medicine s your doctor recommends will depend on many factors. These include your age, your health, whether your TB is active or latent, and whether your TB is drug resistant.

You will need to take your TB medicine s for months. Your doctor will tell you exactly how and when to take your medicine, and for how long. Take your medicine at the same time every day. This could make your TB harder to treat. This is called preventive therapy. Talk with a healthcare provider for a diagnosis. TB is often diagnosed with a skin test. In this test, a small amount of testing material is injected into the top layer of the skin.

If a certain size bump develops within 2 or 3 days, the test may be positive for tuberculosis infection. Other tests include X-rays and sputum tests.

A blood test can be done in place of the TB skin test. If you will be spending time with a person or people with active TB, wear a face mask and try not to stay in a small enclosed space with poor ventilation. People who work in situations where there is a high risk for encountering people infected with TB, such as healthcare workers, should be tested for TB on a routine basis. In countries outside the U. Health Home Conditions and Diseases.

The following are the stages of TB: Exposure. This happens when a person has been in contact with, or exposed to, another person who has TB. The exposed person will have a negative skin test, a normal chest X-ray, and no signs or symptoms of the disease. Latent TB infection. This happens when a person has TB bacteria in his or her body, but does not have symptoms of the disease. The infected person's immune system walls off the TB organisms, and the TB remains inactive throughout life in most people who are infected.

This person would have a positive skin test, but a normal chest X-ray.