From the Introduction: "A core duty and primary function of any government is protection of the public's health and safety. Field epidemiology--including investigation of disease outbreaks and clusters--is a critical, basic government function conducted by public health agencies at the state and federal levels. The federal government's authority to protect public health and safety is found in the US Constitution. And while states address the protection of public health and safety in their individual constitutions, each state is also vested with 'police powers,' that is, inherent authority to impose restrictions on private rights for the sake of public welfare, order, and security. Both federal and state authorities are subject to the limitations and restraints of the US Constitution. [...] This chapter provides an overview of legal considerations relating to field epidemiology and, more specifically, epidemiologic investigations. It discusses the interplay of federal and state laws; legal issues related to data collection, analysis, and dissemination, including health information privacy; special or unique jurisdictions; and state and federal cooperation in emergency responses, including investigations of disease outbreaks that may be terrorism-related."
U.S. Centers for Disease Control and Prevention: https://www.cdc.gov/