Learn how the discovery that tuberculosis is contagious led to both medical progress and new forms of discrimination, in this video adapted from AMERICAN EXPERIENCE: The Forgotten Plague: Tuberculosis in America. In the early 20th century, new understanding of how tuberculosis spread lowered mortality rates in some communities but rates continued to climb in poor, crowded neighborhoods. The public health response to protect the community at large began to trump the individual rights of a patient, especially those from minority and working class backgrounds.