Pulmonary tuberculosis (TB)

Pulmonary tuberculosis (TB) is a contagious bacterial infection that involves the lungs. It may spread to other organs.


Pulmonary tuberculosis (TB) is caused by the bacteria Mycobacterium tuberculosis (M. tuberculosis) . You can get TB by breathing in air droplets from a cough or sneeze of an infected person. The resulting lung infection is called primary TB. Most people recover from primary TB infection without further evidence of the disease. The infection may stay inactive (dormant) for years. However, in some people it can reactivate. Most people who develop symptoms of a TB infection first became infected in the past. In some cases, the disease becomes active within weeks after the primary infection.

The following persons are at high risk of active TB:

Your risk of catching TB increases if you:

The following factors may increase the rate of TB infection in a population:


The primary stage of TB does not cause symptoms. When symptoms of pulmonary TB occur, they can include:

Other symptoms that can occur:



TB is preventable, even in those who have been exposed to an infected person. Skin testing for TB is used in high risk populations or in people who may have been exposed to TB, such as health care workers.

People who have been exposed to TB should have a skin test as soon as possible and have a follow-up test at a later date, if the first test is negative.

A positive skin test means you have come into contact with the TB bacteria. It does not mean that you have active TB or are contagious. Talk to your provider about how to prevent getting TB.

Prompt treatment is very important in preventing the spread of TB from those who have active TB to those who have never been infected with TB.

Some countries with a high incidence of TB give people a vaccine called BCG to prevent TB. But, the effectiveness of this vaccine is limited and it is not usually used in the United States.

People who have had BCG may still be skin tested for TB. Discuss the test results (if positive) with your provider.