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CDC’s National Notifiable Diseases Surveillance System (NNDSS) is a multifaceted public health disease surveillance system that gives public health officials powerful capabilities to monitor the occurrence and spread of diseases.  Facets of NNDSS are used by numerous state, territorial, tribal, and local health departments; and by partner organizations, such as the Council of State and Territorial Epidemiologists (CSTE), to

• facilitate collecting, managing, analyzing, interpreting, and disseminating health related data for diseases designated as nationally notifiable,
• develop and maintain national standards (for example, consistent case definitions for nationally notifiable diseases) applicable across states,
• maintain the official national notifiable diseases statistics,
• provide detailed data to CDC programs to aid in identifying specific disease trends,
• work with states and partners to implement and assess prevention and control programs, and
• publish summarized data findings from 57 state, territorial, and local reporting jurisdictions weekly and annually in the Morbidity and Mortality Weekly Report (MMWR).

A public health surveillance system, such as NNDSS, is defined as encompassing everything that supports the activity of collecting and monitoring disease data, including policies, laws, people, partners, information systems, processes, and resources at the local, state, and national levels.

Effective public health surveillance begins at the local- and state-health department levels.  They work with a variety of healthcare providers, including laboratories, hospitals, and private providers, to obtain case reports on many infectious and some non-infectious diseases.  Each state has laws mandating that providers report cases of certain diseases to state and/or local health departments.  These data provide the direction and scope of many state and local health department activities, from detecting individual cases and controlling outbreaks to implementing prevention and intervention activities.  State health departments support national public health surveillance by voluntarily sharing a portion of their data with CDC.  The data from states are used by CDC to monitor disease trends, assess the effectiveness of prevention and control measures, identify populations or geographic areas at high risk, formulate prevention strategies, develop public health policies, and work with the international community to identify and contain global outbreaks.

A key component of NNDSS is the National Electronic Disease Surveillance System (NEDSS).  NEDSS provides data and information technology (IT) standards, support, and leadership to state, local, and territorial health departments that in turn provide CDC with aggregate data on nationally notifiable diseases and conditions.  NEDSS’s capabilities are used to

• support reportable disease surveillance by improving information sharing between healthcare providers and health departments and between states and CDC,
• support Electronic Laboratory Reporting as part of the Meaningful Use initiative to improve public health disease reporting, and
• increase information sharing and system interoperability between state health departments to improve multi-state disease detection and containment.