DIS work in health departments, community health centers, and other similar locations to perform contact tracing, partner services, and emergency response. The DIS role was initially established to work in the field of STD prevention. However, these public health professionals have ground-level investigative skills that have also become key components of public health infectious disease threats, tuberculosis outbreak response, HIV exposure notification, other infectious disease control efforts, and emergency response. DIS have expertise in essential skills such as communication, contact tracing, interviewing, counseling, case analysis, and provider and community engagement. As the health care landscape evolves, DIS are needed even more as patient navigators and network builders to ensure patients are linked to care through expanded relationships with health care providers. DIS are a critical part of the public health infrastructure and in building the link to health care.