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.
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.
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.
Nine million people globally become sick with TB every year. Around 9,000 cases of TB are reported each year in the UK, mostly in major cities.
The prevalence of new cases of TB across London is the highest of any city in Western Europe (around 3,300 in 2010).
North Central London has the highest percentage of TB cases in London.