a contagious bacterial disease :: Article Creator What Is Tuberculosis? Medically reviewed by Brian H Wetchler, DO Tuberculosis (TB) is a curable, contagious bacterial disease that primarily affects the lungs. With treatment, the outcome for TB is good. However, 1.5 million people around the world die from tuberculosis each year. According to the World Health Organization, it is the world's most deadly infectious disease. In the United States, western Europe, and other high-income areas, TB disease rates are very low. It is most common in sub-Saharan Africa, Eastern Europe, and Asia. Here's what you need to know about the stages of tuberculosis infection, how it's treated, and what it means for your health. Types Once the bacteria that causes TB enters the lungs, it may stay dormant for a period of time, or it may cause disease in a matter of weeks. When the bacteria lie dormant, it is known as a latent TB infection. When the ba...