Tuberculosis (TB)

What is tuberculosis?

Tuberculosis (TB) is an infection caused by slow-growing bacteria that grow best in areas of the body that have lots of blood and oxygen. That’s why it is most often found in the lungs. This is called pulmonary TB. But TB can also spread to other parts of the body, which is called extrapulmonary TB. Treatment is often a success, but it is a long process. It takes about 6 to 9 months to treat TB.

Tuberculosis is either latent or active.

• Latent TB means that you have the TB bacteria in your body, but your body’s defenses (immune system) fight the infection and try to keep it from turning into active TB. This means that you don't have any symptoms of TB right now and can't spread the disease to others. If you have latent TB, it can become active TB.
• Active TB means that the TB bacteria are growing and causing symptoms. If your lungs are infected with active TB, it is easy to spread the disease to others.

How is TB spread to others?

Pulmonary TB (in the lungs) is contagious. It spreads when a person who has active TB breathes out air that has the TB bacteria in it and then another person breathes in the bacteria from the air. An infected person releases even more bacteria when he or she does things like cough or laugh.

If TB is only in other parts of the body (extrapulmonary TB), it does not spread easily to others.

Who is most at risk for TB?

Some people are more likely than others to get TB. This includes people who:

• Have HIV or another illness that weakens their immune system.
• Have close contact with someone who has active TB, such as living in the same house as someone who is infected with TB.
• Care for a patient who has active TB, such as doctors or nurses.
• Live or work in crowded places such as prisons, nursing homes, or homeless shelters, where other people may have active TB.
• Have poor access to health care, such as homeless people and migrant farm workers.
• Abuse drugs or alcohol.
• Travel to or were born in places where untreated TB is common, such as Latin America, Africa, Asia, Eastern Europe, and Russia.

It is important for people who are at a high risk for getting TB to get tested once or twice every year.

What are the symptoms?

Most of the time when people are first infected with TB, the disease is so mild that they don't even know they have it. People with latent TB don't have symptoms unless the disease becomes active.

Symptoms of active TB may include:

• A cough that brings up thick, cloudy, and sometimes bloody mucus from the lungs (called sputum) for more than 2 weeks.
• Tiredness and weight loss.
• Night sweats and a fever.
• A rapid heartbeat.
• Swelling in the neck (when lymph nodes in the neck are infected).
• Shortness of breath and chest pain (in rare cases).

How is TB diagnosed?

Doctors usually find latent TB by doing a tuberculin skin test. During the skin test, a doctor or nurse will inject TB antigens under your skin. If you have TB bacteria in your body, within 2 days you will get a red bump where the needle went into your skin. The test can't tell when you became infected with TB or if it can be spread to others.

To find pulmonary TB, doctors test a sample of mucus from the lungs (sputum) to see if there are TB bacteria in it. Doctors sometimes take a chest X-ray to help find pulmonary TB.

To find extrapulmonary TB, doctors can take a sample of tissue (biopsy) to test. Or you might get a CT scan or an MRI so the doctor can see pictures of the inside of your body.

How is it treated?

Most of the time, doctors combine four antibiotics to treat active TB. It’s important to take the medicine for active TB for at least 6 months. Almost all people are cured if they take their medicine just like their doctor says to. If tests still show an active TB infection after 6 months, then treatment continues for another 2 or 3 months.

Most people with latent TB are treated with only one antibiotic that they take for 9 months. This reduces their risk for getting active TB.

If you miss doses of your medicine, or if you stop taking your medicine too soon, your treatment may fail or have to go on longer. You may have to start your treatment over again. This can also cause the infection to get worse or lead to an infection that is resistant to antibiotics. This is much harder to treat.

TB can only be cured if you take all the doses of your medicine. A doctor or nurse may have to watch you take it to make sure that you never miss a dose and that you take it the proper way. You may have to go to the doctor's office every day, or a nurse may come to your home or work. This is called direct observational treatment. It helps people follow all of the instructions and keep up with their treatment, which can be complex and take a long time. Cure rates for TB have greatly improved because of this type of treatment.

If active TB is not treated, it can damage your lungs or other organs and can be deadly.

Frequently Asked Questions

Tuberculosis (TB) is caused by Mycobacterium tuberculosis, slow-growing bacteria that thrive in areas of the body that are rich in blood and oxygen, such as the lungs.

If you have latent tuberculosis (TB), you do not have symptoms and cannot spread the disease to others. If you have active TB, you do have symptoms and can spread the disease to others. Which specific symptoms you have will depend on whether your TB infection is in your lungs (the most common site) or in another part of your body (extrapulmonary TB).

There are other conditions with symptoms similar to TB, such as pneumonia or lung cancer.

Symptoms of active TB in the lungs

Symptoms of active TB in the lungs begin gradually and develop over a period of weeks or months. You may have one or two mild symptoms and not even know that you have the disease.

Common symptoms include:

• A cough with thick, cloudy, and sometimes bloody mucus from the lungs (sputum) for more than 2 weeks.
• Fever, chills, and night sweats.
• Fatigue and weakness.
• Loss of appetite and unexplained weight loss.
• Shortness of breath and chest pain.

Symptoms of an active TB infection outside the lungs

Symptoms of TB outside the lungs (extrapulmonary TB) vary widely depending on which area of the body is infected. For example, back pain can be a symptom of TB in the spine, or your neck may get swollen neck when lymph nodes in the neck are infected.

Tuberculosis (TB) develops when Mycobacterium tuberculosis bacteria are inhaled into the lungs. The infection usually stays in the lungs, but the bacteria can travel through the bloodstream to other parts of the body (extrapulmonary TB).

An initial (primary) infection can be so mild that you don't even know you have an infection. In a person who has a healthy immune system, the body usually fights the infection by walling off (encapsulating) the bacteria into tiny capsules called tubercles. The bacteria remain alive but cannot spread to surrounding tissues or other people. This stage is called latent TB, and most people never go beyond it.

A reaction to a tuberculin skin test is how most people find out they have latent TB. It takes about 48 hours after the test for a reaction to develop, which is usually a red bump where the needle went into the skin. Or you could have a blood test (QuantiFERON-TB Gold) that provides results in about 24 hours.

If a person's immune system becomes unable to prevent the bacteria from growing, the TB becomes active. Of people who have latent TB, 5% (1 person in 20) will develop active TB within 2 years after the initial infection. Another 5% of people who have latent TB will develop active TB at some point in their life.¹

People who have latent TB may be at risk for developing the active disease if they:

• Have a condition or disease that weakens their immune system, such as human immunodeficiency virus (HIV) infection, some cancers, or poorly controlled diabetes.
• Have poor access to health care, such as homeless people, migrant farm workers, or people who abuse alcohol or drugs.
• Take medications that contain corticosteroids for a long time or are taking tumor necrosis factor-alpha antagonists (used to treat rheumatoid arthritis or Crohn's disease).
• Have a condition that results in an impaired immune system, which can occur in older adults, newborns, women who have recently given birth, or people who have had an organ transplant and are taking medications to prevent organ rejection.
• Have a chronic lung disease caused by breathing in tiny sand or silica particles (silicosis).
• Have celiac disease.²
• Have had gastric bypass surgery or a gastrectomy.
• Are 10% or more under their healthy body weight.

Active TB in the lungs

Active TB in the lungs (pulmonary TB) is contagious. TB spreads when a person who has active disease exhales air that contains TB-causing bacteria and another person inhales the bacteria from the air. These bacteria can remain floating in the air for several hours. Coughing, sneezing, laughing, or singing releases more bacteria than breathing. TB is more likely to spread in situations where:

• People are living together in crowded conditions. TB can spread rapidly in nursing homes, hospitals, homeless shelters, schools, military barracks, and prisons.
• People live in the same house with a person who has active TB. This increases the chance of inhaling TB-causing bacteria and developing an infection. TB is not spread by handling objects that have been touched by a person who has TB.

Generally, after 2 weeks of treatment with antibiotics, you cannot spread an active pulmonary TB infection to other people.

Skipping doses of medication can delay a cure and cause a relapse. In these cases, you may need to start treatment over. Relapses usually occur within 6 to 12 months after treatment. Not taking the full course of treatment also allows antibiotic-resistant strains of the bacteria to develop, making treatment more difficult.

Without treatment, active TB can cause serious complications, such as:

• Pockets or cavities that form in the lungs. These damaged areas may cause bleeding in the lungs or may become infected with other bacteria and form pockets of pus (abscesses).
• A hole that forms between nearby airways in the lungs (bronchopleural fistula).
• Difficulty breathing because of blocked airways.

TB can be fatal if it is not treated.

Active TB outside the lungs

Active TB that occurs outside the lungs (extrapulmonary TB) is not spread easily to other people. You take the same medications that are used to treat pulmonary TB. You may need other treatments depending on where in your body the infection is growing and how severe it is.

TB in certain groups of people

Infants and children and people with HIV or AIDS who have active TB need special care.

People are at increased risk of infection with tuberculosis (TB) when they:

• Have close contact (such as living in the same house) with someone who has active TB, which can be spread to others. Active TB is very contagious.
• Care for people who have untreated TB, such as health professionals.
• Live or work in crowded conditions where they can come into contact with people who may have untreated active TB. This includes people who live or work in prisons, nursing homes, military barracks, or homeless shelters.
• Have poor access to health care, such as homeless people, migrant farm workers, or people who abuse alcohol or drugs.
• Travel to or from regions where untreated TB is common, such as Latin America (countries in Central America, South America, and the Caribbean), Africa, Asia, Eastern Europe, and Russia.

People who have an infection that cannot spread to others (latent TB infection) are at risk of developing active TB if they:

• Have a condition or disease that weakens the immune system, such as human immunodeficiency virus (HIV) infection, some cancers, or poorly controlled diabetes.
• Have poor access to health care, such as homeless people, migrant farm workers, or people who abuse alcohol or drugs.
• Take medications that contain corticosteroids for a long period of time or are taking tumor necrosis factor-alpha antagonists (used to treat rheumatoid arthritis or Crohn's disease)..
• Have a condition that results in an impaired immune system, which can occur in older adults, newborns, women who have recently given birth, or people who have had an organ transplant and are taking medications to prevent organ rejection.
• Have a chronic lung disease caused by inhaling sand-like dust (silicosis).
• Have celiac disease.²
• Have had gastric bypass surgery or a gastrectomy.
• Are 10% or more under their healthy body weight.

Call your doctor immediately if you have:

• Symptoms (such as an ongoing cough with fever, fatigue, and weight loss) that could be caused by tuberculosis (TB).
• Been in close contact with someone who has untreated active TB, which can be spread to others, or you have had lengthy close contact with someone you think has untreated active TB.
• Blurred vision or color blindness and are taking ethambutol for TB.
• Yellowing of your skin and the whites of your eyes (jaundice) or you have abdominal pain and you are taking isoniazid or other medications for TB.

Call your doctor if you:

• Have recently had a TB skin test and you have a red bump at the needle site. You need to have a reaction measured by a health professional within 2 to 3 days after the test. This measurement is important in deciding whether you need more tests or treatment.

Watchful Waiting

Watchful waiting is a wait-and-see approach. If you get better on your own, you won't need treatment. If you get worse, you and your doctor will decide what to do next.

If you have symptoms of TB (an ongoing cough with fever, fatigue, and weight loss), you should not wait to get treatment. Contact your doctor or other health professional as soon as possible.

If you have been exposed to someone who has active TB, don't wait to see if you develop symptoms. Contact your doctor or other health professional to get a tuberculosis skin test.

Who To See

Health professionals and public health agencies can help you discover whether you have tuberculosis (TB). These include:

• Your local public health department.
• Primary care doctors (general practitioner, family medicine doctor, internist, pediatrician).
• Pulmonologists, which are doctors who specialize in treating lung problems.
• Infectious disease specialists.

Health professionals and public health agencies can also help you with treatment. They include:

• Your local public health department, which often has a TB specialist.
• Primary care doctors who know about treating TB.
• Pulmonologists, which are doctors who specialize in treating lung problems.
• Infectious disease specialists.
• Other specialists to treat complications.

If you have multidrug-resistant TB, you may need to go to a hospital that specializes in treating this type of TB.

To prepare for your appointment, see the topic Making the Most of Your Appointment

Diagnosing active TB in the lungs

Doctors diagnose active tuberculosis (TB) in the lungs (pulmonary TB) by using a medical history and physical examination, and by checking your symptoms (such as an ongoing cough, fatigue, fever, or night sweats). Doctors will also look at the results of:

• Sputum cultures. Testing mucus from the lungs (sputum culture) is the best way to diagnose active TB. If TB bacteria grows from your samples, sensitivity testing is done on the bacteria. These tests will show which medications will kill the bacteria. Results of sensitivity tests can take between 1 and 6 weeks because TB-causing bacteria grow very slowly. Your doctor may start treatment before results are returned if it's likely that you have TB. Researchers are working on new tests that may give quicker results.
• Chest X-rays. A chest X-ray cannot diagnose active TB. A chest X-ray usually is done if you have:
  • A positive tuberculin skin test (also called a TB skin test, PPD test, or Mantoux test).
  • Symptoms of active TB, such as a persistent cough, fatigue, fever, or night sweats.
  • An uncertain reaction to the tuberculin skin test because of a weakened immune system, or to a previous bacille Calmette-Guerin (BCG) vaccination.

Diagnosing latent TB in the lungs

A tuberculin skin test will show whether you have latent TB. The test also will show if you have ever had a TB infection. See an illustration of a tuberculin skin test.

QuantiFERON-TB Gold is a blood test that has been approved by the U.S. Food and Drug Administration (FDA) to help detect latent TB.³ It can help diagnose TB when results from a tuberculin skin test are uncertain. The test can also tell if a person who has had a BCG vaccination has a TB infection. It requires only one visit to the doctor or clinic, instead of two visits as required for the tuberculin skin test.

Diagnosing TB outside the lungs

Diagnosing TB in other parts of the body (extrapulmonary TB) requires more testing. You may have:

• A sample of the affected area taken out (biopsy). The sample is sent to a lab to look for TB-causing bacteria.
• A urine culture to look for TB infection in the kidneys (renal TB).
• A sample of fluid around the spine (cerebrospinal fluid) taken to look for a TB infection in the brain (TB meningitis).
• A CT scan to diagnose TB that has spread throughout the body (miliary TB) and to detect lung cavities caused by TB.
• An MRI scan to look for TB in the brain or the spine.

Testing for HIV infection is often done at the time of TB diagnosis. You may also have a blood test for hepatitis.⁴

Tests during TB treatment

During treatment, sputum tests are done once a month—or more often—to make sure the antibiotics are working. You may have a chest X-ray at the end of treatment to use as a comparison in the future.

You may have tests to see if TB medications are harming other parts of your body. These tests may include:

• Liver function tests.
• Eye tests, especially if you are taking ethambutol for TB treatment.
• Hearing tests, especially if you are taking streptomycin for TB treatment.

Early Detection

All cases of TB are reported to the local or state health department because the disease can spread to others and cause outbreaks. Major health authorities keep track of TB outbreaks and encourage early testing for people who are at risk for developing the disease.

The Centers for Disease Control and Prevention (CDC) recommend TB testing for people who:⁵

• Have a human immunodeficiency virus (HIV) infection or another condition that puts them at risk for TB.
• Spend a lot of time with a person who has active TB disease, which can be spread to others.
• Inject illegal drugs.
• Were born in parts of the world where tuberculosis is common, such as Latin America and the Caribbean, Africa, Asia, Eastern Europe, and Russia.
• Live or work in nursing homes, homeless shelters, migrant farm camps, prisons, or jails.

People who have a high risk for developing TB usually have a skin test (tuberculin test) on a regular basis. Health professionals often are given a tuberculin skin test when they begin work in a hospital or nursing home, with retesting every 6 to 12 months.

Doctors treat tuberculosis (TB) with antibiotics to kill the TB bacteria. These medications are given to everyone who has TB, including infants, children, pregnant women, and people who have a weakened immune system.

People who have TB that cannot be spread to others (latent TB) also receive treatment to prevent the infection from becoming active.

When treating active TB, health experts recommend:⁶

• Using more than one medication to prevent multidrug-resistant TB. The standard treatment begins with four medications given for 2 months.
• Continuing treatment for 4 to 9 months or longer if necessary. The number of medicines used during this time depends on the results of sensitivity testing.
• Using directly observed therapy (DOT). This means visits with a health professional who watches you every time you take your medication. A cure for TB requires you to take all doses of the antibiotics. These visits ensure that people follow medication instructions, which is helpful because of the long treatment course for TB.
• Trying a different combination of medications if the treatment is not working because of drug resistance (when tests show that TB-causing bacteria are still active).
• Using different treatment programs for people infected with the human immunodeficiency virus (HIV), people infected with TB bacteria that are resistant to one or more medicines, pregnant women, and children.

When treating latent TB, experts recommend:¹

• Using one medicine to kill the TB bacteria and prevent active TB. The standard treatment is isoniazid taken for 9 months. For people who cannot take isoniazid for 9 months, sometimes a 6-month treatment program is done.
• Treatment with rifampin for 4 months. This is an acceptable alternate treatment, especially for people who have been exposed to bacteria that is resistant to isoniazid.

Treatment for extrapulmonary tuberculosis

Treatment for tuberculosis outside the lungs (extrapulmonary TB) usually is the same as for pulmonary TB. You may need other medications or forms of treatment depending on where the infection is in the body and whether complications develop.

You may need treatment in a hospital if you have:

• Severe symptoms.
• TB that is resistant to multiple-drug therapy.

What To Think About

For active TB, there are different treatment recommendations for people with HIV and TB, people with drug-resistant TB, children with active TB, and pregnant women with active TB.

If you miss doses of medication or you stop treatment too soon, your treatment may go on longer or you may have to start over. This can also cause the infection to get worse or lead to antibiotic-resistant infections that are much harder to treat.

A cure for TB requires you to take all doses of the antibiotics. This may mean daily visits with a health professional who watches you take the medication. This is known as directly observed therapy (DOT).

Taking all of the medications is especially important for people who have an impaired immune system. They may be at an increased risk for a relapse because the original TB infection was never cured.

Relapses usually occur within 6 to 12 months after treatment. Treatment for relapse is based on the severity of the disease and which medications were used during the first treatment.

Doctors also use medication treatment to prevent people with a latent TB infection from developing active TB. Health experts recommend this for people who have a positive tuberculin skin test but no symptoms of TB. Treatment is especially important for people with latent TB who:

• Have HIV infection or AIDS.
• Have close contact with a person who has active TB.
• Have a chest X-ray that suggests a TB infection, but have not had a complete course of treatment.
• Inject illegal drugs.
• Have a medical condition or take medicine that weakens the immune system.
• Have had a tuberculin skin test within the past 2 years that was negative but now the skin test is showing a TB infection (positive).

Avoid getting active TB

Active tuberculosis (TB) is an infection that is spreading in a person's body, and it is very contagious.

The World Health Organization (WHO) estimates that one-third of the world's population is infected with the bacteria that causes TB. To avoid getting an active TB infection:

• Do not spend long periods of time in stuffy, enclosed rooms with anyone who has active TB until that person has been treated for at least 2 weeks.
• Use protective measures, such as face masks, if you work in a facility that cares for people who have untreated TB.
• If you live with someone who has active TB, help and encourage the person to follow treatment instructions.

Prevent latent TB from becoming active

Usually, treatment with isoniazid for about 9 months or rifampin for 4 months can prevent a latent TB infection from developing into active TB. Treatment is recommended for anyone with a skin test that shows a TB infection, and is especially important for people who:

• Are known to or are likely to be infected with the human immunodeficiency virus (HIV).
• Have close contact with a person who has active TB.
• Have a chest X-ray that suggests a TB infection, and have not had a complete course of treatment.
• Inject illegal drugs.
• Have a medical condition or take medications that weaken the immune system.
• Have had a tuberculin skin test within the past 2 years that did not show a TB infection but now a new test indicates an infection.

Can the TB vaccine help?

A TB vaccine (bacille Calmette-Guerin, or BCG) is used in many countries to prevent TB. However, this vaccination is almost never used in the United States because:

• The risk of getting TB is low in the U.S.
• The vaccine is not effective in adults who receive it.
• The BCG vaccine may cause a tuberculin skin test to indicate a TB infection even if a person is not infected with TB. This complicates the use of the tuberculin skin test to check people for TB.

Home treatment for tuberculosis (TB) focuses on taking the medications correctly to reduce the risk of developing multidrug-resistant TB. Keep all your medical appointments, take your medications as prescribed, and report any side effects of the medications, especially vision problems. If you plan to move during the time that you are being treated, let your health professional know so that arrangements can be made for you to continue the treatment.

Home treatment includes:

• Not going to work or school while you can spread the TB infection. Sleep in a bedroom by yourself until you can no longer infect other people.
• Opening windows in a room where you must stay for a while, if the weather allows it. This can help get rid of TB bacteria from the air in the room.
• Eating a balanced diet to provide your body with the nutrients that you need to fight the infection. If you need help, ask to talk with a registered dietitian.
• Covering your mouth when you sneeze or cough. Until you have been on antibiotics for about 2 weeks, you can easily spread the disease to others. After coughing, dispose of the soiled tissue in a covered container. Talk with your health professional about other precautions you can take to prevent the spread of TB.

If you have been exposed to TB

If you live with someone who has active TB or you know that you have been exposed to someone who has the disease, see your health professional for testing. A tuberculin skin test (also called a TB skin test, PPD test, or Mantoux test) that indicates a TB infection means you need treatment to prevent active TB.

Active tuberculosis (TB)

Several antibiotics are used at the same time to treat active tuberculosis (TB) disease. For people who have multidrug-resistant TB, treatment may continue for as long as 24 months. These antibiotics are given as pills or injections.

Extrapulmonary TB

TB disease that occurs outside the lungs (extrapulmonary TB) usually is treated with the same medications and for the same length of time as active TB in the lungs (pulmonary TB). However, TB throughout the body (miliary TB) or TB that affects the brain or the bones and joints in children may be treated for at least 12 months.

Corticosteroid medications also may be given in some severe cases to reduce inflammation. They may be helpful for children at risk of central nervous system problems caused by TB and for people who have conditions such as high fever, TB throughout the body (miliary TB), pericarditis, or peritonitis.

Latent TB

One antibiotic usually is used to treat latent TB infection, which cannot be spread to others but can develop into active TB disease. The antibiotic is taken for 4 to 9 months.¹

Medication Choices

Multiple-drug therapy to treat TB usually involves taking four antibiotics at the same time. This is the standard treatment for active TB. The four most commonly chosen medications are:⁷

• Isoniazid (IHN, Nydrazid).
• Rifampin (Rifadin, Rimactane).
• Pyrazinamide.
• Ethambutol (Myambutol).

Doctors sometimes use other medicines if treatment isn't effective or the person is infected with drug-resistant TB bacteria. Other medication choices include:⁷

• Rifapentine (Priftin).
• Streptomycin (STM).
• Ethionamide (Trecator-SC).
• Cycloserine (Seromycin).
• Capreomycin (Capastat Sulfate).
• Levofloxacin (Levaquin, Quixin).
• Moxifloxacin (Avelox, Vigamox).

What To Think About

It is important to take all doses of the treatment medications. This ensures a cure and reduces the risk of a relapse of the disease and the development of antibiotic-resistant bacteria. It will also help prevent the spread of TB to people around you.

Surgery is rarely used to treat tuberculosis (TB). However, it may be used to treat complications of an infection in the lungs or another part of the body.

Surgery is used to:

• Repair lung damage, such as serious bleeding that cannot be stopped any other way, or repeated lung infections other than TB.
• Remove a pocket of bacteria that cannot be killed with long-term medication treatment.

Surgery has a high success rate, but it also has a risk of complications, which may include infections other than TB and shortness of breath after surgery.

Surgery for TB outside the lungs

Surgery occasionally may be needed to remove or repair organs damaged by TB outside the lungs (extrapulmonary TB) or to prevent other rare complications, such as:

• TB infection of the brain (TB meningitis). Your doctor may surgically place a tube (shunt) that drains excess fluid from the brain to prevent a buildup of pressure that can further damage the brain.
• TB infections of the heart (TB pericarditis). Your surgeon may partially remove or repair the infected sac around the heart.
• TB infection of the kidneys (renal TB). Your surgeon may need to either remove your infected kidney or repair the kidney or other parts of the urinary system.
• TB infection of the joints. You may need surgery to repair damaged areas of your spine or joints (orthopedic surgery).

There is no other treatment for tuberculosis at this time.

Organizations

• Early Disease Detection

Citations

1. Lahart CJ (2005). Tuberculosis and other mycobacterial diseases. In RE Rakel, ET Bope, eds., Conn's Current Therapy 2005. pp. 315–321. Philadelphia: Elsevier Saunders.

2. Ludvigsson JF, et al. (2007). Coeliac disease and risk of tuberculosis: A population based cohort study. Thorax, 62(1): 23–28.

3. Centers for Disease Control and Prevention (2005). Guidelines for using the QuantiFERON^®-TB test for diagnosing latent Mycobacterium tuberculosis infection. MMWR, 54(RR-15): 49–55.

4. Centers for Disease Control and Prevention (2002). CDC's Response to Ending Neglect: The Elimination of Tuberculosis in the United States. Atlanta: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention.

5. Division of Tuberculosis Elimination, National Center for HIV, STD, and TB Prevention (2005). Questions and Answers About TB. Available online: http://www.cdc.gov/nchstp/tb/faqs/qa.htm.

6. American Thoracic Society, Centers for Disease Control and Prevention, Infectious Diseases Society of America (2003). Treatment of tuberculosis. American Journal of Respiratory and Critical Care Medicine, 167(4): 603–662.

7. Fitzgerald D, Haas DW (2005). Mycobacterium tuberculosis. In GL Mandell et al., eds., Principles and Practice of Infectious Diseases, 6th ed., pp. 2852–2886. Philadelphia: Elsevier.

Other Works Consulted

• Gelband H (2006). Regimens of less than six months for treating tuberculosis. Cochrane Database of Systematic Reviews (1). Oxford: Update Software.

• Wilkinson D (2003). Drugs for preventing tuberculosis in HIV infected persons. Cochrane Database of Systematic Reviews (1). Oxford: Update Software.

• Ziganshina L, Garner P (2006). Tuberculosis, search date July 2005. Online version of Clinical Evidence (15): 1–15.