Tuberculosis (TB) is a bacterial infection spread through inhaling tiny droplets from the coughs or sneezes of an infected person.
It is a serious condition but can be cured with proper treatment.
TB mainly affects the lungs. However, it can affect any part of the body, including the bones and nervous system.
Typical symptoms of TB include:
- having a persistent cough for more than three weeks that brings up phlegm, which may be bloody
- weight loss
- night sweats
- high temperature (fever)
- tiredness and fatigue
- loss of appetite
You should see a GP if you have a cough that lasts more than three weeks or if you cough up blood.
Read more about the symptoms of tuberculosis.
What causes tuberculosis?
TB is caused by a bacterium called mycobacterium tuberculosis.
TB that affects the lungs is the only form of the condition that is contagious and usually only spreads after prolonged exposure to someone with the illness. For example, TB often spreads within a family who live in the same house.
In most healthy people, the immune system (the body's natural defence against infection and illness) kills the bacteria and you have no further symptoms.
However, sometimes the immune system cannot kill the bacteria, but manages to prevent it from spreading in the body. This means you will not have any symptoms, but the bacteria will remain in your body. This is known as latent TB.
If the immune system fails to kill or contain the infection, it can spread to the lungs or other parts of the body and symptoms will develop within a few weeks or months. This is known as active TB.
Latent TB could develop into an active TB infection at a later date, particularly if your immune system becomes weakened.
Read more about the causes of tuberculosis.
How is tuberculosis treated?
With treatment, a TB infection can usually be cured. Most people will need a course of antibiotics, usually for six months.
Several different antibiotics are used. This is because some forms of TB are resistant to certain antibiotics. If you are infected with a drug-resistant form of TB, treatment can last as long as 18 months.
If you are in close contact with someone who has TB, tests may be carried out to see if you are also infected. These can include a chest X-ray, blood tests and a skin test called the Mantoux test.
Read more about diagnosing tuberculosis and treating tuberculosis.
The Bacillus Calmette-Guérin (BCG) vaccine can provide effective protection against TB in up to eight out of 10 people who are given it.
Currently, BCG vaccinations are only recommended for groups of people who are at a higher risk of developing TB.
This includes children living in areas with high rates of TB or those who have close family members from countries with high TB rates.
It is also recommended that some people, such as healthcare workers, are vaccinated due to the increased risk of contracting TB while working.
Read more about tuberculosis vaccine.
How common is TB?
Before antibiotics were introduced, TB was a major health problem in the UK. Nowadays, the condition is much less common. However, in the last 20 years TB cases have gradually increased, particularly among ethnic minority communities who are originally from places where TB is more common.
In 2011, 8,963 cases of TB were reported in the UK. Of these, more than 6,000 of these cases affected people who were born outside the UK.
It is estimated that one-third of the world's population is infected with latent TB. Of these, about 10% will become active at some point.