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National Notifiable Diseases Surveillance System (NNDSS)

To protect Americans from serious disease, the National Notifiable Diseases Surveillance System (NNDSS) helps public health monitor, control, and prevent about 120 diseases. These diseases are important to monitor nationwide and include infectious diseases such as Zika, foodborne outbreaks such as E. coli, and noninfectious conditions such as lead poisoning. About 3,000 public health departments gather and use data on these diseases to protect their local communities. Through NNDSS, CDC receives and uses these data to keep people healthy and defend America from health threats.

NNDSS is a multifaceted program that includes the surveillance system for collection, analysis, and sharing of health data. It also includes policies, laws, electronic messaging standards, people, partners, information systems, processes, and resources at the local, state, territorial, and national levels.

Supporting Public Health Surveillance in Jurisdictions and at CDC

Notifiable disease surveillance begins at the level of local, state, and territorial public health departments (also known as jurisdictions). Jurisdictional laws and regulations mandate reporting of cases of specified infectious and noninfectious conditions to health departments. The health departments work with healthcare providers, laboratories, hospitals, and other partners to obtain the information needed to monitor, control, and prevent the occurrence and spread of these health conditions.

The CDC Division of Health Informatics and Surveillance (DHIS) supports NNDSS by receiving, securing, processing, and providing nationally notifiable infectious diseases data to disease-specific CDC programs. DHIS also supports local, state, and territorial public health departments in helping them collect, manage, and submit case notification data to CDC for NNDSS. DHIS provides this support through funding, health information exchange standards and frameworks, electronic health information systems, and technical support through the NNDSS web site, tools, and training. DHIS and the CDC programs publish statistical data based on NNDSS to support recognition of outbreaks, monitoring of shifts in disease patterns, and evaluation of disease control activities.

These programs collaborate with the Council of State and Territorial Epidemiologists (CSTE) to determine which conditions reported to local, state, and territorial public health departments are nationally notifiable. The CDC programs, in collaboration with subject matter experts in CSTE and in health departments, determine what data elements are included in national notifications. Health departments participating in NNDSS voluntarily submit case notification data to DHIS and also submit some data directly to CDC programs.

NNDSS Modernization Initiative

With the evolution of technology and data and exchange standards, CDC is strengthening and modernizing the infrastructure supporting NNDSS. As part of the CDC Surveillance Strategy (, the NNDSS Modernization Initiative (NMI) is enhancing the system's ability to provide more comprehensive, timely, and higher quality data than ever before for public health decision making.

Through this multi-year initiative, CDC is increasing the robustness of the NNDSS technological infrastructure so that it is based on interoperable, standardized data and exchange mechanisms.