Tuberculosis.

Essential facts Tuberculosis (TB) is an infection caused by a bacterium, mycobacterium tuberculosis. While it can affect any part of the body, only pulmonary TB is infectious. According to the charity TB Alert, there were 5,758 cases of TB in the UK in 2015 and 39% of them were in London. This represented a fall from a peak of 8,919 cases in 2011. Left untreated, TB is life-threatening, but is usually curable with antibiotics. The sooner it is diagnosed and treated, the better, both for the person's health and in preventing them from passing the infection on to others.