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Norovirus infection

Last updated: February 11, 2021

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Noroviruses are a frequent cause of viral gastroenteritis in individuals of all ages worldwide. Transmission commonly occurs from person to person, as well as through contact with contaminated surfaces, food, and water. Given their virulence and short incubation period, illnesses caused by noroviruses may quickly lead to outbreaks, which must be reported. The elderly, immunocompromised patients, and those who reside in long-term care facilities are at an increased risk of contracting the illness. The clinical presentation of norovirus infection includes acute-onset vomiting and watery diarrhea. Diagnosis can be confirmed with reverse transcription polymerase chain reaction (RT-PCR). Treatment is supportive and mainly involves fluid replacement therapy.

  • Peak incidence: November–March (winter months)
  • Community outbreaks (in nursing homes, hospitals, preschools, cruise ships, etc.) are common
  • Elderly and immunocompromised patients are commonly affected.
  • Most common cause of

References:[1][2][3]

Epidemiological data refers to the US, unless otherwise specified.

  • Pathogen: Norovirus; is a non‑enveloped RNA calicivirus.
  • Transmission
    • Fecal‑oral route through contaminated food or water, person‑to‑person contact, via airborne droplets, and contact with contaminated surfaces
    • The virus is highly virulent.
    • Individuals are highly infectious during the acute phase and 24–72 hours following onset of symptoms

Viral pathogens in gastroenteritis (Rotavirus is a Reovirus, Norovirus is a Calicivirus): Rotate Reo, the calico cat off to Norway!

References:[4]

  • Incubation period: 12–48 hours
  • Nausea and acute-onset vomiting
  • Watery, non-bloody diarrhea
  • Abdominal cramps
  • Fever
  • Symptoms resolve after 48–72 hours.
  • Norovirus should be suspected in potentially exposed individuals if vomiting and/or diarrhea consisting ≥ 2 loose stools occur within a 24‑hour period.
  • Clinical suspicion of norovirus infection should be confirmed with reverse transcription PCR (RT-PCR).
    • Very sensitive method that can detect the virus from various specimens, including stool, vomit, food, and water.
  • Enzyme immunoassays: not a standard procedure due to low sensitivity (∼ 50%)

References:[5][6]

References:[7]

The differential diagnoses listed here are not exhaustive.

References:[7][8]

Obligation to report

  • Health care providers are required to report all outbreaks.
  • Many cases go underreported, as symptoms are usually mild in healthy individuals → higher chance of further transmission

References:[9][10][11]

  1. Leggiadro RJ. Norovirus Gastroenteritis in Immunocompromised Patients. Pediatr Infect Dis J. 2013; 32 (4): p.388.
  2. Norovirus - Burden of Norovirus Illness and Outbreaks. https://www.cdc.gov/norovirus/php/illness-outbreaks.html. Updated: July 8, 2014. Accessed: March 22, 2017.
  3. Hall AJ, Vinjé J, Lopman B et al . Updated Norovirus Outbreak Management and Disease Prevention Guidelines. Morbidity and Mortality Weekly Report. 2011; 60 (3): p.1-15.
  4. Hall AJ. Noroviruses: The Perfect Human Pathogens?. J Infect Dis. 2012; 205 (11): p.1622-1624. doi: 10.1093/infdis/jis251 . | Open in Read by QxMD
  5. Verhoef L, Hewitt J, Barclay L. Norovirus Genotype Profiles Associated with Foodborne Transmission, 1999–2012. Emerg Infect Dis. 2015; 21 (4): p.592-599. doi: 10.3201/eid2104.141073 . | Open in Read by QxMD
  6. Norovirus - Diagnostic Methods. https://www.cdc.gov/norovirus/lab-testing/diagnostic.html. Updated: February 1, 2017. Accessed: March 22, 2017.
  7. Khan ZZ. Norovirus. In: Wallace MR, Norovirus. New York, NY: WebMD. http://emedicine.medscape.com/article/224225. Updated: October 20, 2015. Accessed: March 22, 2017.
  8. Kayser-Jones J, Schell ES, Porter C, Barbaccia JC, Shaw H. Factors contributing to dehydration in nursing homes: inadequate staffing and lack of professional supervision.. J Am Geriatr Soc.. 1999; 47 (10): p.1187-94.
  9. Guidelines for Suspected Norovirus Outbreaks. http://www.dhhr.wv.gov/oeps/disease/FnW/Viral/Documents/Norovirus_Outbreak_Toolkit.pdf. . Accessed: March 22, 2017.
  10. Norovirus - Reporting and Surveillance for Norovirus. https://www.cdc.gov/norovirus/reporting/index.html. Updated: December 28, 2016. Accessed: March 22, 2017.
  11. Guideline for the Prevention and Control of Norovirus Gastroenteritis Outbreaks in Healthcare Settings, 2011. https://www.cdc.gov/infectioncontrol/pdf/guidelines/norovirus-guidelines.pdf. Updated: May 4, 2011. Accessed: March 22, 2017.
  12. Norovirus in Healthcare Facilities Fact Sheet. https://www.cdc.gov/hai/pdfs/norovirus/229110-ANoroCaseFactSheet508.pdf. Updated: September 6, 2011. Accessed: March 22, 2017.
  13. Drinking Water - Diseases and Contaminants. https://www.cdc.gov/healthywater/drinking/private/wells/disease/norovirus.html. Updated: July 1, 2015. Accessed: March 22, 2017.
  14. Haill CF, Newell P, Ford C et al. Compartmentalization of wards to cohort symptomatic patients at the beginning and end of norovirus outbreaks.. J Hosp Infect. 2012; 82 (1): p.30-35. doi: 10.1016/j.jhin.2012.05.015 . | Open in Read by QxMD
  15. Managing Norovirus Infections in Hospitals. http://www.confidenceconnected.com/blog/2012/09/12/managing_norovirus_infections_in_hospitals/. Updated: September 12, 2012. Accessed: March 22, 2017.
  16. Norovirus - Preventing Norovirus Infection. https://www.cdc.gov/norovirus/preventing-infection.html. Updated: July 15, 2016. Accessed: March 22, 2017.