CDC launched NORS in 2009 as a web-based platform into which health departments enter outbreak information. Through NORS, CDC collects reports of enteric disease outbreaks caused by bacterial, viral, parasitic, chemical, toxin, and unknown agents, as well as waterborne outbreaks of non-enteric disease.
National foodborne and waterborne disease outbreak surveillance has been a core function of CDC since the 1970s. Two surveillance systems handle this responsibility: the Waterborne Disease and Outbreak Surveillance System (1971-present) and the Foodborne Disease Outbreak Surveillance System (1973-present). Foodborne disease outbreak data have been collected electronically since 1998. NORS was designed to integrate the outbreak reporting systems and enhance national outbreak reporting with new components.
A foodborne disease outbreak (FBDO) is defined as the occurrence of two or more cases of a similar illness resulting from the ingestion of a common food. FBDOs are reported to CDC on a standard reporting form. Outbreaks of known etiology are those for which laboratory evidence of a specific agent is obtained that meets specified criteria for that agent. Most reports are received from state and local health departments; they also may be received from tribal, territorial, or federal agencies. Not included in this surveillance system are FBDOs occurring on cruise ships and FBDOs due to consumption of food outside the United States, even if the illness occurs within the United States. Because the size of outbreaks can vary widely, and because improvements in outbreak detection, investigation, and reporting are likely to lead to a disproportionate increase in reports of relatively smaller outbreaks, tracking the number of reported outbreak-associated infections is more informative and valuable than tracking the number of reported outbreaks. The FBDO surveillance system is an open database; reporting agencies can add, modify, or delete current or past reports.
Tracking disease associated with outbreaks attributed to food vehicles may help us determine how to prioritize outbreak prevention efforts and may enable us to determine the efficacy of focused prevention, education and other efforts on particular food commodity groups.
Other organizations that collaborate with CDC on outbreak surveillance and prevention include CSTE, the Environmental Protection Agency (EPA), the Food and Drug Administration (FDA), and the Department of Agriculture (USDA).