Reporting and Surveillance for Norovirus
Currently, state, local, and territorial health departments are not required to report individual cases of norovirus illness to a national surveillance system. They may not know about such cases because most hospitals and doctor’s offices do not have capability to test for norovirus. The virus is usually diagnosed only when an outbreak happens.
Health care providers should report all outbreaks of acute gastroenteritis, including suspected outbreaks of norovirus, to the appropriate state, local or territorial health department.
Health departments are encouraged to report all suspected and confirmed norovirus outbreaks through the National Outbreak Reporting System (NORS) and CaliciNet.
NORS was launched by CDC in 2009 to collect information on outbreaks of foodborne, waterborne, and enteric disease that spread from person-to-person, animals, environmental surfaces, and other or unknown ways. Public health agencies can report all outbreaks of gastroenteritis, including norovirus illness, through this web-based system. This information is used to determine where norovirus outbreaks commonly occur, how the virus is spread, and specific food or water sources involved. In turn, this helps with identifying the best ways to prevent and control norovirus illness and outbreaks.
Definition of a Norovirus Outbreak
An outbreak of norovirus is defined as an occurrence of two or more similar illnesses resulting from a common exposure that is either suspected or laboratory-confirmed to be caused by norovirus.
CDC developed CaliciNet in 2009. It is a network of public health and food regulatory laboratories that submit norovirus sequences identified from outbreaks into a national database. The information is used to link norovirus outbreaks that may be caused by common sources (such as food), monitor trends, and identify emerging norovirus strains. As of February 2012, public health laboratories in 25 states have been certified by the CDC to participate in CaliciNet. States that are not yet certified may contribute through designated CaliciNet outbreak support centers, including the CDC.
CDC is using New Vaccine Surveillance Network (NVSN) and Foodborne Diseases Active Surveillance Network (FoodNet) to do norovirus testing on patients with gastroenteritis. This will help generate new estimates of norovirus illness and monitor trends over time.
- Updated Norovirus Outbreak Management and Disease Prevention Guidelines (2011)
- Guideline for the Prevention and Control of Norovirus Gastroenteritis Outbreaks in Healthcare Settings (2011)
- A Norovirus Outbreak Control Resource Toolkit for Healthcare Settings (2012)
- New Vaccine Surveillance Network (NVSN)
- Foodborne Diseases Active Surveillance Network (FoodNet)
- National Outbreak Reporting System (NORS)
- Estimates of Foodborne Illness in the United States
- CDC's Vessel Sanitation Program
- CDC Feature: Surveillance for Norovirus Outbreaks
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