Tuberculosis (TB) is a disease caused by bacteria, the tubercle bacillus. TB can affect many parts of the body, but the commonest type of TB causes an infection of the lungs (pulmonary tuberculosis). It is spread fom person to person by coughs and sneezes.
Another form of TB is caught from drinking milk from cows infected with tuberculosis. Its spread can be prevented by heat-treating milk (pasteurising or sterilising). This type of TB starts in the gut and often affects the bones and joints, but TB can take hold almost anywhere. When the main organ affected is not the lungs, it is referred to as extra-pulmonary TB.
Not everyone infected with tuberculosis becomes ill from it. When people do, the illness is slow and prolonged and treatment with antibiotics also has to be prolonged. Strains that are resistent to many, sometimes all, of the drugs currently available are becoming increasingly common.
HIV infection which causes AIDS seriously reduces our resistance to tuberculosis. Statistics now often record whether someone dying of tuberculosis was infected with HIV or not (called HIV sero-positive and HIV sero-negative TB cases).