FAQ

Q-1: What is TB?

Tuberculosis (TB) is a disease caused by bacteria called Mycobacterium tuberculosis. The bacteria usually attack the lungs. But TB bacteria can attack any part of the body such as the kidney, spine, and brain. If not treated properly, TB disease can be fatal.

TB is spread through the air from one person to another. The bacteria are put into the air when a person with TB disease of the lungs or throat coughs, sneezes, speaks, or sings. People nearby may breathe in these bacteria and become infected.

However, not everyone infected with TB bacteria becomes sick. People, who are infected, but not sick, have what is called latent TB infection. People who have latent TB infection do not feel sick, do not have any symptoms, and cannot spread TB to others. But some people with latent TB infection go on to get TB disease.

There is good news. People with TB disease can be treated if they seek medical help. Even better, most people with latent TB infection can take medicine so that they will not develop TB disease.

Q-2: How is TB spread?

TB is spread through the air from one person to another. The bacteria are put into the air when a person with TB disease of the lungs or throat coughs, sneezes, speaks, or sings. People nearby may breathe in these bacteria and become infected.

When a person breathes in TB bacteria, the bacteria can settle in the lungs and begin to grow. From there, they can move through the blood to other parts of the body, such as the kidney, spine, and brain.

TB disease in the lungs or throat can be infectious. This means that the bacteria can be spread to other people. TB in other parts of the body, such as the kidney or spine, is usually not infectious.

People with TB disease are most likely to spread it to people they spend time with every day. This includes family members, friends, and co-workers or schoolmates.

Q-3: What is latent TB infection?

In most people who breathe in TB bacteria and become infected, the body is able to fight the bacteria to stop them from growing. The bacteria become inactive, but they remain alive in the body and can become active later. This is called latent TB infection. People with latent TB infection:

• Have no symptoms
• Don’t feel sick
• Can’t spread TB bacteria to others
• Usually have a positive skin test reaction or positive TB blood test
• May develop TB disease if they do not receive treatment for latent TB infection

Many people who have latent TB infection never develop TB disease. In these people, the TB bacteria remain inactive for a lifetime without causing disease. But in other people, especially people who have weak immune systems, the bacteria become active, multiply, and cause TB disease.

Q-4: What is TB disease?

If the immune system can’t stop TB bacteria from growing, the bacteria begin to multiply in the body and cause TB disease. The bacteria attack the body and destroy tissue. If this occurs in the lungs, the bacteria can actually create a hole in the lung. Some people develop TB disease soon after becoming infected (within weeks) before their immune system can fight the TB bacteria. Other people may get sick years later, when their immune system becomes weak for another reason.

Babies and young children often have weak immune systems. People infected with HIV, the virus that causes AIDS, have very weak immune systems. Other people can have weak immune systems, especially people with any of these conditions:

• Substance abuse
• Diabetes mellitus
• Silicosis
• Cancer of the head or neck
• Leukemia or Hodgkin’s disease
• Severe kidney disease
• Low body weight
• Certain medical treatments (such as corticosteroid treatment or organ transplants)
• Specialized treatment for rheumatoid arthritis or Crohn’s disease

Symptoms of TB disease depend on where in the body the TB bacteria are growing. TB disease in the lungs may cause symptoms such as:

• A bad cough that lasts 2 weeks or longer
• Pain in the chest
• Coughing up blood or sputum (phlegm from deep inside the lungs)

Other symptoms of TB disease are:

• Weakness or fatigue
• Weight loss
• No appetite
• Chills
• Fever
• Sweating at night

Q-5: WhatTB Risk Factors?

Some people develop TB disease soon after becoming infected (within weeks) before their immune system can fight the TB bacteria. Other people may get sick years later, when their immune system becomes weak for another reason.

Overall, about 5 to 10% of infected persons who do not receive treatment for latent TB infection will develop TB disease at some time in their lives. For persons whose immune systems are weak, especially those with HIV infection, the risk of developing TB disease is much higher than for persons with normal immune systems.

Generally, persons at high risk for developing TB disease fall into two categories:

• Persons who have been recently infected with TB bacteria
• Persons with medical conditions that weaken the immune system

Persons who have been Recently Infected with TB Bacteria

This includes:

• Close contacts of a person with infectious TB disease
• Persons who have immigrated from areas of the world with high rates of TB
• Children less than 5 years of age who have a positive TB test
• Groups with high rates of TB transmission, such as homeless persons, injection drug users, and persons with HIV infection
• Persons who work or reside with people who are at high risk for TB in facilities or institutions such as hospitals, homeless shelters, correctional facilities, nursing homes, and residential homes for those with HIV

Persons with Medical Conditions that Weaken the Immune System

Babies and young children often have weak immune systems. Other people can have weak immune systems, too, especially people with any of these conditions:

• HIV infection (the virus that causes AIDS)
• Substance abuse
• Silicosis
• Diabetes mellitus
• Severe kidney disease
• Low body weight
• Organ transplants
• Head and neck cancer
• Medical treatments such as corticosteroids or organ transplant
• Specialized treatment for rheumatoid arthritis or Crohn’s disease

Glossary

• BCG– a vaccine for TB named after the French scientists who developed it, Calmette and Guérin. BCG is rarely used in the United States, but it is often given to infants and small children in other countries where TB is common.

• Chest x-ray – a picture of the inside of your chest. A chest x-ray is made by exposing a film to x-rays that pass through the chest. A doctor can look at this film to see whether TB bacteria have damaged the lungs.

• Contact – a person who has spent time with a person with infectious TB.

• Culture – a test to see whether there are TB bacteria in your phlegm or other body fluids. This test can take 2 to 4 weeks in most laboratories.

• Directly observed therapy (DOT) – a way of helping patients take their medicine for TB. If you get DOT, you will meet with a health care worker every day or several times a week. You will meet at a place you both agree on. This can be the TB clinic, your home or work, or any other convenient location. You will take your medicine while the health care worker watches.

• Extensively drug-resistant TB (XDR TB) - XDR TB is a rare type of TB disease that is resistant to nearly all medicines used to treat TB.

• Extrapulmonary TB – TB disease in any part of the body other than the lungs (for example, the kidney, spine, brain, or lymph nodes).

• HIV infection – infection with the human immunodeficiency virus, the virus that causes AIDS (acquired immunodeficiency syndrome). A person with both latent TB infection and HIV infection is at very high risk for developing TB disease.

• INH or isoniazid – a medicine used to prevent TB disease in people who have latent TB infection. INH is also one of the four medicines often used to treat TB disease.

• Latent TB infection – a condition in which TB bacteria are alive but inactive in the body. People with latent TB infection have no symptoms, don't feel sick, can't spread TB to others, and usually have a positive skin test reaction. But they may develop TB disease if they do not receive treatment for latent TB infection.

• Multidrug-resistant TB (MDR TB) – TB disease caused by bacteria resistant to two or more of the most important medicines: INH and RIF.

• Mycobacterium tuberculosis – bacteria that cause latent TB infection and TB disease.

• Negative – usually refers to a test result. If you have a negative TB skin test reaction, you probably do not have TB infection.

• Positive – usually refers to a test result. If you have a positive TB skin test reaction, you probably have TB infection.

• Pulmonary TB – TB disease that occurs in the lungs, usually producing a cough that lasts 3 weeks or longer. Most TB disease is pulmonary.

• Resistant bacteria – bacteria that can no longer be killed by a certain medicine.

• Rifampin (RIF) – one of the four medicines often used to treat TB disease. It is considered a
• first-line drug.

• Smear – a test to see whether there are TB bacteria in your phlegm. To do this test, lab workers smear the phlegm on a glass slide, stain the slide with a special stain, and look for any TB bacteria on the slide. This test usually takes 1 day to get the results.

• Sputum – phlegm coughed up from deep inside the lungs. Sputum is examined for TB bacteria using a smear; part of the sputum can also be used to do a culture.

• TB blood test – a new test that uses a blood sample to find out if you are infected with TB bacteria. The test measures the response to TB proteins when they are mixed with a small amount of blood. Examples of these TB blood tests include QuantiFERON®-TB Gold In-tube (QFT-GIT) and T-Spot®.TB test.

• TB disease – an illness in which TB bacteria are multiplying and attacking a part of the body, usually the lungs. The symptoms of TB disease include weakness, weight loss, fever, no appetite, chills, and sweating at night. Other symptoms of TB disease depend on where in the body the bacteria are growing. If TB disease is in the lungs (pulmonary TB), the symptoms may include a bad cough, pain in the chest, and coughing up blood. A person with TB disease may be infectious and spread TB bacteria to others.

• TB skin test – a test that is often used to find out if you are infected with TB bacteria. A liquid called tuberculin is injected under the skin on the lower part of your arm. If you have a positive reaction to this test, you probably have TB infection. Other tests will be needed to find out if you have latent TB infection or TB disease.

• Tuberculin or PPD – a liquid that is injected under the skin on the lower part of your arm during a TB skin test. If you have latent TB infection, you will probably have a positive reaction to the tuberculin.
(Source- https://www.cdc.gov/tb/publications/faqs/pdfs/qa.pdf)