How TB spreads
TB bacteria are spread through the air from one person to another. The TB bacteria are put into the air when a person with TB disease of the lungs or throat coughs, speaks, or sings. People nearby may breathe in these bacteria and become infected.
TB is not spread by:
- shaking someone's hand
- sharing food or drink
- touching bed linens or toilet seats
- sharing toothbrushes
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 coworkers or schoolmates.
Signs and symptoms of TB
Symptoms of TB disease depend on where in the body the TB bacteria are growing. TB bacteria usually grow in the lungs (pulmonary TB). TB disease in the lungs may cause symptoms such as
- a bad cough that lasts 3 weeks or longer
- pain in the chest
- coughing up blood or sputum (phlegm from deep inside the lungs)
- weakness or fatigue
- weight loss
- no appetite
- sweating at night
Symptoms of TB disease in other parts of the body depend on the area affected. People who have latent TB infection do not feel sick, do not have any symptoms, and cannot spread TB to others.
Testing and Treatment
There are two types of tests for TB infection: the TB skin test and the TB blood test. A person’s health care provider should choose which TB test to use. Factors in selecting which test to use include the reason for testing, test availability, and cost. Generally, it is not recommended to test a person with both a TB skin test and a TB blood test.
Tuberculosis is treatable and curable. Active, drug-susceptible TB disease is treated with a standard 6 to 9 month course of 4 antimicrobial drugs that are provided with information, supervision and support to the patient by a health worker or trained volunteer. Without such support, treatment adherence can be difficult and the disease can spread. The vast majority of TB cases can be cured when medicines are provided and taken properly.
Some cases of tuberculosis are caused by mycobacteria that are resistant to the commonly used anti-tuberculous drugs. Such resistant bacteria frequently arise as a result of incomplete or intermittent treatment. These cases are complicated by the need for multiple drugs for even more prolonged periods of time. Tuberculosis due to resistant mycobacteria can be incurable and fatal. Thus, it is essential that the prescribed treatment be followed accurately for the full course of therapy. Many treatment programs use "directly observed therapy" where a health worker directly observes patients taking their medications to ensure compliance and help minimize resistance to therapy.
A person with latent TB infection should take medicine to prevent getting TB disease later. This is called “preventive” treatment.