Tuberculosis is caused by the bacterium Mycobacterium tuberculosis. It is spread through airborne droplets when people with active TB cough, sneeze or speak. While most people who get infected never develop active TB, some may develop the disease if their immune system becomes weak. Symptoms include cough, fever, night sweats and weight loss. Diagnosis involves tests of sputum, blood and x-rays. Treatment requires a combination of antibiotics taken for at least 6-12 months. Prevention includes BCG vaccination and controlling the spread from active cases.