What is TB?
Tuberculosis is an airborne disease caused by the bacterium Mycobacterium tuberculosis which primarily affects the lungs but can also affect other organs. People infected with TB do not feel sick, do not have symptoms and are not contagious unless and until their infection develops into active TB disease. TB bacteria may be released into the air by TB-diseased persons when they sneeze, cough or speak.
How TB Spreads
The difference between TB disease and TB infection
Once the TB germ enters the body infection occurs. However, most people's immune systems stop the TB infection from growing and the TB germ goes into an inactive state. An inactive infection does not cause sickness or symptoms and cannot be transmitted to others. Still, a person with TB infection will test positive for TB and may develop TB disease in the future without preventive therapy.
If the immune system cannot make the TB germ inactive, the infected person will have active TB disease. People with TB disease in the throat or lungs can easily spread the TB bacteria. People with TB disease in the brain, kidneys or spine cannot spread the TB bacteria and are not infectious.
If you have active, uncomplicated TB disease, you must complete a six- to 12-month treatment with three to four TB drugs that must be prescribed by a doctor.
Symptoms of TB
- A bad cough lasting more than two weeks
- Coughing up blood
- Chest pains
- Fatigue or weakness
- Poor appetite and weight loss
- Night sweats
Who should get a TB test?
You should be tested for TB infection if:
- You have spent time with someone with infectious TB.
- You live in an environment where TB disease is common, including some nursing homes and most homeless shelters, prisons, jails and migrant farm camps.
- You think you might have TB disease.
- You are from a country where TB disease is common, such as countries in Africa, Latin America, the Caribbean and Asia.
- You have HIV infection or another condition that places you at high risk for TB disease.
- You inject drugs and/or share needles.
Those at high risk for TB disease include:
- People living with HIV or other diseases that weaken the immune system.
- People who became infected with TB within the last two years.
- People who share needles and/or inject drugs.
- People who have had close contact with someone who has infectious TB.
Testing and treatment
A TB skin test is an easy way to find out if you have TB infection. TB tests can be performed at your local health department or doctor's office.
How the test is done
The skin test for TB is simple. A small amount of testing fluid is injected just under the skin on the lower arm. Two or three days after the test, a health care worker will measure the skin reaction to the test to determine whether the test is positive or negative for TB infection. A positive result usually means you have TB infection. If you test positive, other tests will be performed to determine whether or not you have developed TB disease. These tests can include chest X-ray and laboratory tests.
What are the treatments?
People who test positive for TB infection may take medications to keep from developing TB disease. This usually involves the use of a drug called isoniazid or INH, which kills the inactive TB bacteria and prevents developing active TB disease. INH is usually taken for 6-9 months. Sometimes people at high risk for TB are given the medication even if they test negative for TB infection. Anyone who tests positive for TB, but does not receive preventive therapy, must see a doctor immediately if any TB symptoms develop.
Multi-drug resistant TB
A drug-resistant strain of TB bacteria will not respond to drugs ordinarily used to treat the disease. These strains develop when people with active TB disease do not take their medicine as prescribed and the bacteria develop resistance to the drug. Drug-resistant TB is a very serious problem and very expensive and difficult to treat.
Drug resistance is common among patients who:
- Have been exposed to someone with drug-resistant TB.
- Do not take their medication regularly.
- Do not take all of their medication.
- Develop TB again after taking TB medication in the past.
- Come from areas where drug-resistant TB is common (Southeast Asia, Latin America and some Caribbean countries)