What Is Tuberculosis?
TB is a disease that forms when M. tb bacteria infects the body.
M. tb most often affects the lungs but can occur in almost any other organ, such as the:
There are two types of TB infections:
- Latent TB.
- Active TB disease.
Latent TB occurs when your body "walls off" the infection in the lungs, preventing symptoms.
But with active TB, the infection:
- "Breaks free" from the lung's immune cells, causing damage to the organ.
- Causes symptoms.
- Could spread to other parts of the body or to other people.
About one in four people in the world have latent TB infection. Most people with latent TB don't develop active disease. In fact, only about one in 10 people with latent TB forms an active TB infection at some point in their life.
The American Lung Association cites that about 10 million people in the world have active TB.
Rates of TB are very low in the U.S. and have been falling for years. The CDC reports 7,882 cases of TB in the U.S. in 2021.
Tuberculosis causes
Active TB is contagious, but it doesn't spread from one person to another very easily.
People cannot get TB from:
- Sharing toothbrushes, food, drinks, glasses, or utensils.
- Touching bedsheets or toilet seats.
- Hugging someone or shaking their hand.
The bacteria travel through the air when someone with TB talks or coughs. If someone breathes in air particles containing the bacteria, the TB can infect them.
After TB germs enter someone's lungs, they can grow and travel through the bloodstream — and to other organs in the body.
A person with TB can only release TB germs into the air if they have the disease in their lungs or throat. A person with TB in other organs of the body, such as the kidney or brain, can't pass it on to others.
Tuberculosis risk factors and complications
People are at risk for TB infection if they have spent time around someone else with active TB disease. Even after breathing in the bacteria, though, it may take weeks or years for a person to form active disease.
People with latent TB can't spread the disease to others since they can't release the germs into the air. As mentioned before, people with latent TB cannot release bacteria into the air, hence they cannot spread the infection to other individuals.
Those at risk for TB infection of any kind include:
- People who spend time around others with TB.
- People from parts of the world with high rates of TB, such as India or parts of Asia or Africa.
- Children under 5 years of age who have had a positive TB test.
- People who have HIV or who share needles to inject drugs.
- People who are homeless or live in refugee camps.
- People who work in places where others have a high risk for TB, such as prisons, homeless shelters, or hospitals.
People with latent TB are more likely to get active TB if they have a medical condition that weakens their immune system.
This includes those who:
- Have HIV.
- Have diabetes.
- Have a history of cancer, especially head and neck cancer, or are receiving chemotherapy for cancer.
- Have severe kidney disease (especially those on hemodialysis).
- Have silicosis — a type of lung disease.
- Are babies or very young children.
- Have had an organ or bone marrow transplant.
- Have a very low body weight.
- Receive certain treatments for autoimmune disorders, such as RA or IBD.
People with latent TB don't have symptoms or feel sick. But they can develop active TB if they don't receive treatment for their infection.
If a person with active TB disease doesn't receive proper treatment, they can suffer severe complications or even die.
Complications can include:
- Damage to the joints, mainly the hips and knees.
- Pain in the spine and back.
- Swelling around the spine or brain, also known as meningitis.
- Problems in the liver or kidneys.
- Heart problems.
- Severe damage to the lungs.