Tuberculosis (TB) is a contagious bacterial infection primarily affecting the lungs, though it can also impact other parts of the body. It is caused by the bacterium Mycobacterium tuberculosis and spreads through the air when an infected person coughs or sneezes. Symptoms include a persistent cough, chest pain, fever, and weight loss. Diagnosis typically involves a skin test or blood test, followed by chest X-rays to confirm the presence of the disease. Treatment usually requires a long course of antibiotics, often lasting six months or more, to effectively eliminate the bacteria and prevent the spread of TB to others.