​​​​​​​​​​​​Norovirus is a significant source of gastrointestinal illness and contributes up to 50% of all foodborne outbreaks in the United ​States. CaliciNet is a national norovirus outbreak surveillance network, comprised of federal, state and local public health laboratories that detect and subtype norovirus strains associated with gastroenteritis outbreaks. This critical network allows CDC to compare norovirus strains from outbreaks and potentially link them to a common source, monitor circulating strains and detect emerging ones.

Learn more about CaliciNet with these frequently asked questions.

APHL's Role in CaliciNet 

Since CaliciNet's inception in 2009, APHL has worked closely with CDC partners and our members to help advance and champion this critical surveillance network. ​

​​​CaliciNet Network and Capacity Building 

APHL supports CaliciNet activities through training, technical meetings and information dissemination. APHL provides logistical and travel support for annual training workshops for local and state public health laboratorians and coordinates the CaliciNet User Group meeting and other meetings as needed.

​​​CaliciNet Outbreak Support Centers


APHL contracts annually with five CaliciNet Outbreak Support Centers (OSCs), through funding from CDC. The OSC's are certified laboratories that test specimens and sequence strains from norovirus outbreaks from state and local health laboratories that are not certified to participate in CaliciNet.

The additional outbreak testing conducted through the OSC contracts provides a more comprehensive picture of predominating norovirus strains in the US and has provided invaluable information during outbreaks leading to multistate product recalls. Comprehensive CaliciNet data are published on CDC's website.