How is TB contracted
People get TB when they breathe in the TB bacteria, which are spread through the air. But most people won’t get ill because:
- TB bacteria are only in the air after someone with infectious TB coughs or sneezes.
- You need to spend many hours close to a person with infectious TB to breathe in enough bacteria to be at risk.
- Most people's immune systems are strong enough to kill off TB bacteria.
You can not get TB by:
- Shaking someone's hand
- Sharing food or drink
- Touching bed linens or toilet seats
- Sharing toothbrushes
There are two kinds of tests that are used to determine if a person has been infected with TB bacteria: the tuberculin skin test (Mantoux) and TB blood tests (T-Spot).
A positive TB skin test or TB blood test only tells that a person has been infected with TB bacteria. It does not tell whether the person has latent TB or active TB. Other tests, such as a chest x-ray and a sample of sputum, are needed to see whether the person has TB.