Tuberculosis is an infectious airborne disease that typically affects the lungs and is spread through coughs, sneezes, or talking, infecting one third of the world's population each year. It develops when TB bacteria are breathed into the lungs and can increase with factors like poor ventilation; symptoms range from mild to severe like weight loss, fever, and coughing blood. While there is no cure for the most advanced stage, TB is generally treatable with a complex regimen of antibiotics, though treatment can be complicated by HIV co-infection.