Tuberculosis (TB) is a bacterial infection caught from another infected person. The infection mostly occurs in the lungs and lymph glands, but can affect any part of the body. It is most common in Asia and Sub-saharan Africa, but is now becoming more common in parts of the UK. There are different forms and stages of the infection.

In the UK, the routine Bacillus Calmette-Guérin (BCG) vaccination programme delivered through schools to prevent TB has stopped. Now there is a programme of targeted vaccination for individuals who are at greatest risk. This includes children and babies living in areas with high rates of TB or whose parents or grandparents were born in a country with a high prevalence of TB. BCG vaccination does not give complete protection against TB.


Medical text written November 2010 by Dr Richard Chavasse, Consultant in Respiratory Paediatrics, St George’s Healthcare NHS Trust and Honorary Consultant, Royal Brompton Hospital, London UK.

What are the symptoms?

The most frequent symptom of TB disease is a wet or ‘productive’ cough (where mucous or phlegm may be coughed up, although often children may swallow it). The phlegm may be bloodstained. There is often a persisting fever, sweating at night, chest pain and loss of appetite and weight. TB can also cause meningitis, kidney and bone/joint disease. To be infectious to other people you have to be coughing the organism out into the air.

Many people have no symptoms and have a hidden, non-infectious form called ‘Latent TB’. This can reactivate and cause significant illness at some time in the future. It is estimated that one third of people in the world may have latent TB.

What are the causes?

A type of bacteria called Mycobacterium tuberculosis causes TB.

How is it diagnosed?

The organism may be seen (under a microscope) or cultured (grown in a laboratory) from phlegm of an infected individual. If a patient is unable to spit out phlegm it is sometime possible to help using a nebuliser. In children, the overnight stomach contents can be aspirated through a tube passed through the nose into the stomach (naso-gastric tube), allowing samples to be collected for analysis to see if Mycobacterium tuberculosis is present.

A biopsy (removal of a small piece of tissue for further analysis) of an infected gland may also identify the typical changes that are observed in TB infection.

A skin test (mantoux) and/or a blood test (IGRA) may identify people exposed to the infection.

When a person is diagnosed with infectious TB, other people close to them will then be screened to see if they have been exposed.

How is it treated?

TB is curable if it is correctly diagnosed and the right antibiotics are used. Usually four medicines (antibiotics) are prescribed for two months followed by two medicines continuing for a further four months. It is very important to complete the course of treatment. Some TB is resistant to one or more drugs and treatment may need to be longer and more complicated.

Latent TB is treated with two antibiotics for three months (or one antibiotic for six months). The aim is to prevent the infection progressing to symptomatic disease and the risk of infecting other people.

Inheritance patterns and prenatal diagnosis

Inheritance patterns 
Not applicable.

Prenatal diagnosis 
Not applicable.

Is there support?

Information and support in the UK for tuberculosis is provided by the British Lung Foundation (see entry Lung diseases).

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