The document discusses tuberculosis (TB) as a highly contagious disease that can be fatal if left untreated. TB is caused by the Mycobacterium tuberculosis bacteria, which affects the lungs and other organs. It is transmitted through the air via coughing, sneezing, or speaking. In 2014, around 9.6 million people worldwide were infected with TB and 1.5 million died from it. While TB cases have declined in the US since 1992, some countries still have high infection rates. Throughout history, TB has been known by various names describing the horror it caused. Modern treatments now include medications like isoniazid to cure the disease.