National case definition: Norovirus

Date of last revision: November 2008

National notification

Only outbreaks should be notified.

Type of surveillance

Outbreak reports

Case classification – outbreak

Confirmed outbreak

Two or more cases of clinical illness compatible with norovirus that can be epidemiologically linked to one another (i.e. associated by exposure with onsets within a 1-3 day period), at least one of which is laboratory confirmed:

• Community outbreak:
  • Two or more unrelated^{Footnote *} cases of illness compatible with norovirus that can be epidemiologically linked to one another
• Institutional outbreak:
  • Two or more cases of clinical illness compatible with norovirus that are epidemiologically linked in an institutional setting

Clinical evidence

Clinical illness is characterized by acute onset of nausea, vomiting, diarrhea, abdominal pain, myalgia, headache, malaise, low-grade fever or a combination of these symptoms, lasting 24 to 48 hours.

ICD code(s)

• ICD-10 code(s)
  • A08.1 Acute gastroenteropathy due to Norwalk agent
    • Small round structured virus enteritis
• ICD-9CM code(s)
  • 008.63 Norwalk virus
    • Norwalk-like agent

  Footnotes

  Footnote *

  Do not live in a common household, excluding institutions

  Return to footnote * referrer