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Tuberculosis information sheet

Tuberculosis (TB) is an infectious disease caused by bacteria belonging to the Mycobacterium tuberculosis complex. TB is the leading cause of death among curable infectious diseases. The World Health Organization declared TB a global emergency in 1993.

Around 9000 cases of TB are currently reported each year in the United Kingdom, of these, over 6000 affect people who were born outside the UK. Most cases occur in major cities, particularly in London.

Pulmonary TB is the only form of the condition that is contagious and it usually only spreads after prolonged exposure (many hours) 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 kills the bacteria and there are no further symptoms.

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. However, sometimes the immune system cannot kill the bacteria, but manages to prevent it from spreading in the body. Although there are no symptoms the bacteria will remain in the body. This is known as latent TB.

Latent TB could develop into an active TB infection at a later date, particularly if the immune system becomes weakened. About half of those people who develop TB will do so within the first two years of infection – for others active TB may occur many years after their initial infection. TB is curable with a combination of specific antibiotics, treated for at least six months.

Adapted from HPA TB factsheet (Last reviewed: 21 March 2011)

The key source of information for each case is the local TB team. The team collate and manage information for everyone diagnosed with TB in their area. Local PHEC teams may also have information on TB contacts.

Contact tracing for TB

UK guidelines for public health management of TB are that household contacts of every newly identified case of pulmonary TB should be screened. At-risk individuals and any named contacts in the community should also be screened. (NICE)

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