Illustration of lungs infected with tuberculosis. Tuberculosis (TB) is a bacterial infection that usually affects the lungs but can affect other body tissues. It causes inflammation and scarring in the lungs, leading to tissue damage. Here, both lungs (red and blue) contain nodular lesions and abscesses, some of which have led to large cavities. This reduces lung function, making it harder for oxygen to reach vital organs. Commonly called consumption in the 1800s, TB was a widespread cause of death during this period before the invention of vaccines (1921) and antibiotics (1943). Published in 'Illustrations of pulmonary consumption' by Samuel George Morton in 1834.