Tuberculosis (TB): Latent Infection, Active Disease, Testing and Treatment

Tuberculosis (TB) is a bacterial disease that usually attacks the lungs, though it can also affect other parts of the body, including the kidneys, spine and brain. TB occurs in the United States but is more common in some other countries.

Two kinds of TB

Not everyone infected with TB germs gets sick:

Inactive TB can turn into active disease in the future if your immune system becomes weakened for another reason. Active disease can develop weeks to years after infection.

How it spreads

TB is caused by the bacterium Mycobacterium tuberculosis. People with TB disease in the throat or lungs release the germs into the air when they cough, sneeze, talk or sing, and others can be infected by breathing that air. TB is not spread by touching, kissing or sharing food or dishes. You are more likely to catch it from people you live or work with than from people you see briefly.

Who is at risk

Of being infected. Anyone near a person with TB disease can be infected. You are more likely to be near someone with TB disease if you:

• were born in, or often travel to, countries where TB disease is common;
• are a health care worker;
• live or work somewhere TB is more common, such as homeless shelters, jails and nursing homes.

Of getting sick after infection. People more likely to develop TB disease include those who:

• have HIV;
• were infected in the last 2 years;
• have other diseases, such as diabetes, that make it harder to fight the germs;
• have alcohol use disorder or inject illegal drugs;
• were not treated correctly for TB in the past;
• are under age 5, or are older adults;
• take medicines that weaken the immune system, such as those after an organ transplant, steroids, or specialised treatments for some autoimmune diseases.

Symptoms of TB disease

• General: chills and fever, night sweats, weight loss without trying, loss of appetite, weakness or fatigue.
• In the lungs: a cough lasting more than 3 weeks, coughing up blood or sputum (thick mucus from the lungs), chest pain.

Testing

A health care provider or local health department can test for TB germs with a skin test or a blood test. If it is positive, other tests show whether the germs are active: sputum samples and chest x-rays for the lungs, and urine and tissue samples for other parts of the body.

You may need a test if you have symptoms, or if you are at high risk of being near someone with TB disease. People with HIV should also be tested: HIV weakens the immune system, so inactive TB can quickly become active disease, and it needs treatment as soon as possible.

Treatment

Both inactive TB infection and TB disease are treated with antibiotics. Follow the directions exactly: if you don't, the germs can change and become resistant, and the medicine may stop working.

• Inactive TB: medicine for three, four, six or nine months, depending on the plan, to prevent disease later.
• Active TB: usually four, six or nine months. Taken correctly, treatment almost always cures it.
• TB in the lungs or throat: stay home for a few weeks so you don't infect others, and protect the people you live with by covering your nose and mouth, opening windows when you can, and keeping your distance.
• Drug-resistant TB: needs special medicines, can take months or years, and may cause side effects; your provider will monitor you closely.

Following medical advice on testing and treatment keeps you healthy and helps stop TB spreading.

Sources

• MedlinePlus, U.S. National Library of Medicine, "Tuberculosis," drawing on the Centers for Disease Control and Prevention. https://medlineplus.gov/tuberculosis.html
• Rewritten in hubnx's own words.