Skip directly to search Skip directly to A to Z list Skip directly to navigation Skip directly to page options Skip directly to site content

Frequently Asked Questions and Answers About CaliciNet

Q: What is CaliciNet?

A: CaliciNet is a national norovirus outbreak surveillance network of federal, state, and local public health laboratories. CDC launched CaliciNet in 2009 to collect information on norovirus strains associated with gastroenteritis outbreaks in the United States. This network plays an important part in quickly identifying norovirus outbreaks, linking them to a common source, monitoring circulating norovirus strains, and identifying newly emerging norovirus.


Q: Why is CaliciNet important?

A: CaliciNet focuses on norovirus, the leading cause of acute gastroenteritis and foodborne-disease illness in the United States. Norovirus illness can occur any time during the year, but outbreaks are most common in the winter. Also, there can be 50% more norovirus illness in years when there is a new strain of the virus going around.

Through CaliciNet, participating public health laboratories identify norovirus strains that cause gastroenteritis outbreaks. This is critical for linking outbreaks to a common source, such as contaminated food, monitoring circulating strains, and identifying newly emerging strains, such as GII.4 Sydney. Ultimately, the information collected through CaliciNet helps public health professionals better understand noroviruses and develop interventions to prevent them from spreading.


Q: How did CaliciNet get its name?

A: Noroviruses, together with sapoviruses, are part of the family Caliciviridae or caliciviruses. The name calicivirus is derived from the cup-shaped depressions seen on the virus particles when viewed using an electron microscope.


Q: What types of data does CaliciNet collect?

A: The CaliciNet database includes:

  • genetic sequences of norovirus strains associated with gastroenteritis outbreaks in the United States, and
  • basic epidemiologic data, such as transmission route and outbreak setting.

For more information, see CaliciNet data.


Q: How are data collected through CaliciNet?

A: Participating public health laboratories use standardized laboratory protocols to examine the genetic makeup of norovirus strains that are associated with gastroenteritis. These laboratories electronically submit laboratory data, including genetic sequences of norovirus strains, and basic epidemiologic data from outbreaks to the CaliciNet database. Outbreak strains are compared with existing norovirus sequences in the database, helping CDC link outbreaks to a common source, such as contaminated food, monitor circulating strains, and identify newly emerging strains.

For more information, see graphic that shows how CaliciNet works.


Q: How can data collected through CaliciNet be used?

A: The data can be used to:

  • link clusters of norovirus illness to a common source
  • standardize typing of norovirus strains
  • detect and identify newly emerging strains of norovirus
 Top of Page


Q: Who can participate in CaliciNet?

A: Participation in CaliciNet is limited to federal, state, and local public health laboratories in the United States.


Q: How can laboratories participate in CaliciNet?

A: Federal, state, and local public health laboratories can participate in CaliciNet by:

  • Completing a certification process to directly participate in the network.
  • Partnering with a certified CaliciNet Outbreak Support Center or CDC's National Calicivirus Laboratory to report norovirus outbreak data to CaliciNet. There are currently centers in California, Idaho, New York, Tennessee, and Wisconsin.


Q: Do laboratories need to renew their certification?

A: Yes. Participating laboratories must pass a proficiency test each year to maintain certification.


Q: How many laboratories are currently certified to participate?

A: As of 2016, 33 laboratories in 28 states and District of Columbia participate in CaliciNet. For more information, see map of certified CaliciNet states.


Q: How does CaliciNet work with other surveillance systems?

A: CDC links laboratory data collected through CaliciNet with clinical and epidemiologic data obtained through the National Outbreak Reporting System (NORS) to enhance investigation of norovirus outbreaks and monitoring of outbreak trends. NORS is a surveillance system used by public health agencies to report clinical and epidemiologic data for all enteric disease outbreaks as well as waterborne outbreaks of non-enteric disease.

Some CaliciNet labs are also involed in CDC's NoroSTAT, a system designed to improve the timeliness, completeness, and consistency of norovirus outbreak reporting. NoroSTAT links data from National Outbreak Reporting System (NORS) and CaliciNet to quickly evaluate current outbreak activity, make comparisons to previous years, and assess strain-specific norovirus outbreak characteristics, including the impact of new strains on outbreak frequency and severity.


Q: Who can access the data collected through CaliciNet?

A: Only CDC and federal, state, and local public health laboratories that are participating in CaliciNet can access the data. CaliciNet-certified public health laboratories must first get permission from CDC to use the data in studies.

All data in the CaliciNet database are securely submitted. CDC does not distribute any information about specific people or facilities involved in norovirus outbreaks.

CaliciNet data are shared with public health professionals, health departments, and the general public through scientific publications, presentations, and CDC website. For more information, see References and Resources.

 Top of Page