Pathogen safety data sheets: Infectious substances - Norovirus

On this page

Section I: Infectious agent

Name: Norovirus

Synonym or cross reference: Norwalk virus, Norwalk-like virus, winter vomiting disease, acute nonbacterial gastroenteritis, acute diarrhoeal illness, Southampton virus, Desert Shield virus, Cruise Ship virus, Snow Mountain virus, Mexico virus, White River Lordsdale virus, Camberwell virus, Toronto virus, Hawaii virusFootnote 1Footnote 2Footnote 3.

Characteristics: Noroviruses are a group of viruses belonging to the Norovirus genus and the Caliciviridae familyFootnote 14. Based on the sequence of the major capsid protein, these viruses are further divided into 6 genogroups (GI-GVI), consisting of numerous genotypesFootnote 15. GI, GII and GIV are the only genogroups known to infect humans. GIII infect cattle; GV infect miceFootnote 16. Porcine noroviruses belong to GII, although porcine and human noroviruses belong to different genotypes within GIIFootnote 17. GII is the most prevalent Norovirus genotype circulating in humans populations, accounting for more than 95% of all infectionsFootnote 15. Noroviruses are slightly smaller than other viruses in the Caliciviridae family, with a diameter of approximately 27 nmFootnote 5. The edges of the virus, when viewed by electron microscopy, are not well defined. The virus is round, non-enveloped, and has single-stranded, positive-sense, polyadenylated RNAFootnote 1Footnote 2. Norovirus recombination and antigenic drift results in replacement of circulating dominant viruses every 2-3 years, with the new variants able to re-infect hosts immune to previous virusesFootnote 15.

Section II: Hazard identification

Pathogenicity: Norovirus infection causes acute gastroenteritis, characterized by rapid onset of nausea, vomiting, diarrhea, abdominal cramps, abdominal pain, mucus in stool, malaise, headache, and feverFootnote 1Footnote 5. The infection is usually resolved within 12 to 60 hours, although it can last longer in elderly, young children or immunocompromised individualsFootnote 1Footnote 2Footnote 3Footnote 5, and these groups are at greatest risk for mortality and increased morbidityFootnote 1. Up to 30% of Norovirus infections are asymptomatic, however, these individuals are able to transmit the virusFootnote 16.

Epidemiology: Worldwide distribution. Noroviruses infect humans of all ages. Most outbreaks occur in hospitals, nursing homes, dining locations, schools, daycare centres, and vacation venuesFootnote 1Footnote 4. Outbreaks occur throughout the year, but have a distinct winter seasonalityFootnote 1. Because of persistence of Norovirus in the environment, outbreaks can last a long time and have been reported to last over 3 monthsFootnote 1. Noroviruses are responsible for 60-95% of outbreaks of nonbacterial acute infectious diarrheaFootnote 1.

Host range: Humans, pigs, cattle, miceFootnote 17.

Infectious dose: Less than 10 virionsFootnote 2.

Mode of transmission: Norovirus transmission is usually person to person through the fecal-oral routeFootnote 6. It can also be transmitted through the environment, contaminated surfaces, food, water, fomites, and aerosolsFootnote 4Footnote 6.

Incubation period: Onset of symptoms usually takes 15-48 hours from the time of infectionFootnote 2.

Communicability: Individuals can spread virus particles without showing symptoms of diseaseFootnote 2. Those who have recovered from symptoms and those who are asymptomatic can shed infectious virus particles up to three weeks after exposureFootnote 2.

Section III: Dissemination

Reservoir: Shellfish, HumansFootnote 1

Zoonosis: None

Vectors: None

Section IV: Stability and viability

Drug susceptibility: No specific antivirals.

Susceptibility to disinfectants: Formulation R-82 for 10 minutes, 0.25-0.50% sodium hypochlorite for 10-20 minutes, peracetic acid or glutaraldehyde for 5 minutesFootnote 1Footnote 2Footnote 7. Recurrent outbreaks on cruise ships and in tropical resorts have been related to improper decontamination proceduresFootnote 8Footnote 9.

Physical inactivation: Noroviruses are inactivated by temperatures of 71.3°C for 1 minuteFootnote 10. It can survive at pH 2.7 for at least 3 hoursFootnote 10. UV radiation may have intermediate effectFootnote 10.

Survival outside host: Norwoviruses have a protein capsid protecting it from the environmentFootnote 2. They can survive in seawater, groundwater, fresh water, soil, and inanimate surfaces for an unknown period of time. Norwalk virus cannot be cultivated under laboratory conditions as of yet. Feline calicivirus, another member of this family, with similar structure, can survive on glass surfaces for 21-28 days at room temperature and for longer periods at 4°CFootnote 11. At 37°C, feline calcinivirus survives over 24 hoursFootnote 11.

Section V: First aid and medical

Surveillance: Monitor for symptoms and confirm clinicallyFootnote 1. Viral RNA can be detected in stool samples using reverse transcription PCRFootnote 10. ELISA is also available for identifying norovirusesFootnote 3.

Note: All diagnostic methods are not necessarily available in all countries.

First aid/treatment: No specific therapy other than rest, oral rehydration and intravenous electrolyte replacementFootnote 2.

Immunization: NoneFootnote 1

Prophylaxis: None

Section VI: Laboratory hazards

Laboratory-acquired infections: None reported as of 2010.

Source/specimens: Faeces, aerosolized vomitFootnote 1Footnote 6.

Primary hazards: Ingestion, exposure of mucous membranes to infective aerosolsFootnote 6.

Special hazards: None

Section VII: Exposure controls and personal protection

Risk group classification: Risk Group 2Footnote 12.

Containment requirements: Containment Level 2 facilities, equipment, and operational practices for work involving infectious or potentially infectious materials, animals, or cultures.

Protective clothing: Lab coat. Gloves when direct skin contact with infected materials or animals is unavoidable. Eye protection must be used where there is a known or potential risk of exposure to splashesFootnote 13.

Other precautions: All procedures that may produce aerosols, or involve high concentrations or large volumes should be conducted in a biological safety cabinet (BSC). The use of needles, syringes, and other sharp objects should be strictly limited. Additional precautions should be considered with work involving animals or large scale activitiesFootnote 13.

Section VIII: Handling and storage

Spills: Allow aerosols to settle and, wearing protective clothing, gently cover spill with paper towels and apply an appropriate disinfectant, starting at the perimeter and working towards the centre. Allow sufficient contact time before clean upFootnote 13.

Disposal: Decontaminate all wastes that contain or have come in contact with the infectious organism by autoclave, chemical disinfection, gamma irradiation, or incineration before disposingFootnote 13.

Storage: The infectious agent should be stored in leak-proof containers that are appropriately labelledFootnote 13.

Section IX: Regulatory and other information

Regulatory information: The import, transport, and use of pathogens in Canada is regulated under many regulatory bodies, including the Public Health Agency of Canada, Health Canada, Canadian Food Inspection Agency, Environment Canada, and Transport Canada. Users are responsible for ensuring they are compliant with all relevant acts, regulations, guidelines, and standards.

Updated: March 2017

Prepared by: Centre for Biosecurity, Public Health Agency of Canada

Although the information, opinions and recommendations contained in this Pathogen Safety Data Sheet are compiled from sources believed to be reliable, we accept no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information. Newly discovered hazards are frequent and this information may not be completely up to date.

Copyright© Public Health Agency of Canada, 2017 Canada



Footnote 1

Goodgame, R. (2006). Norovirus gastroenteritis. Current Gastroenterology Reports, 8(5), 401-408.

Return to footnote 1 Referrer

Footnote 2

Hutson, A. M., Atmar, R. L., & Estes, M. K. (2004). Norovirus disease: changing epidemiology and host susceptibility factors. Trends in Microbiology, 12(6), 279-287. doi:10.1016/j.tim.2004.04.005

Return to footnote 2 Referrer

Footnote 3

Kesson, A. M., Benwell, N., & Elliott, E. J. (2010). Norovirus diarrhoeal disease in infants and children. The Medical Journal of Australia, 192(2), 108-109.

Return to footnote 3 Referrer

Footnote 4

Gospodarek, E., & Zalas-Wiecek, P. (2009). Noroviruses--tactic of spread. [Norowirusy--taktyka rozprzestrzeniania sie] Przeglad Epidemiologiczny, 63(1), 5-9.

Return to footnote 4 Referrer

Footnote 5

Murray, P. R., Baron, E. J., Jorgensen, J. H., Landry, M. L., & Pfaller, M. A. (Eds.). (2007). Manual of Clinical Microbiology (9th ed.). Washington: ASM Press.

Return to footnote 5 Referrer

Footnote 6

Jimenez, L., & Chiang, M. (2006). Virucidal activity of a quaternary ammonium compound disinfectant against feline calicivirus: a surrogate for norovirus. American Journal of Infection Control, 34(5), 269-273. doi:10.1016/j.ajic.2005.11.009

Return to footnote 6 Referrer

Footnote 7

Magulski, T., Paulmann, D., Bischoff, B., Becker, B., Steinmann, E., Steinmann, J., Goroncy-Bermes, P., & Steinmann, J. (2009). Inactivation of murine norovirus by chemical biocides on stainless steel. BMC Infectious Diseases, 9, 107. doi:10.1186/1471-2334-9-107

Return to footnote 7 Referrer

Footnote 8

Wikswo, M. E., Cortes, J., Hall, A. J., Vaughan, G., Howard, C., Gregoricus, N., & Cramer, E. H. (2011). Disease transmission and passenger behaviors during a high morbidity Norovirus outbreak on a cruise ship, January 2009. Clinical Infectious Diseases : An Official Publication of the Infectious Diseases Society of America, 52(9), 1116-1122. doi:10.1093/cid/cir144

Return to footnote 8 Referrer

Footnote 9

Domenech-Sanchez, A., Juan, C., Perez, J. L., & Berrocal, C. I. (2011). Unmanageable norovirus outbreak in a single resort located in the Dominican Republic. Clinical Microbiology and Infection : The Official Publication of the European Society of Clinical Microbiology and Infectious Diseases, 17(6), 952-954. doi:10.1111/j.1469-0691.2010.03411.x; 10.1111/j.1469-0691.2010.03411.x

Return to footnote 9 Referrer

Footnote 10

Duizer, E., Bijkerk, P., Rockx, B., De Groot, A., Twisk, F., & Koopmans, M. (2004). Inactivation of caliciviruses. Applied and Environmental Microbiology, 70(8), 4538-4543. doi:10.1128/AEM.70.8.4538-4543.2004

Return to footnote 10 Referrer

Footnote 11

Rzezutka, A., & Cook, N. (2004). Survival of human enteric viruses in the environment and food. FEMS Microbiology Reviews, 28(4), 441-453. doi:10.1016/j.femsre.2004.02.001

Return to footnote 11 Referrer

Footnote 12

Human Pathogens and Toxins Act. S.C. 2009, c. 24. Government of Canada, Second Session, Fortieth Parliament, 57-58 Elizabeth II, 2009, (2009).

Return to footnote 12 Referrer

Footnote 13

Public Health Agency of Canada. (2004). In Best M., Graham M. L., Leitner R., Ouellette M. and Ugwu K. (Eds.), Laboratory Biosafety Guidelines (3rd ed.). Canada: Public Health Agency of Canada.

Return to footnote 13 Referrer

Footnote 14

International Committee on Taxonomy of Viruses (ICTV). Available online at

Return to footnote 14 Referrer

Footnote 15

White, P.A. (2014) Evolution of norovirus. Clinical Microbiology and Infection, 20(8):741-745.

Return to footnote 15 Referrer

Footnote 16

Morillo, S.G.; Timenstsky, M. D. (2011) Norovirus: an overview. Revista da Associaçao Medica Brasileira, 57(4): 453-458.

Return to footnote 16 Referrer

Footnote 17

Mattison, K.; Shukla, A.; Cook, A.; Pollari, F.; Friendship, R.; Kelton, D.; Bidawid, S.; Farber, J.M. (2007) Human Noroviruses in Swine and Cattle, Emerging Infectious Diseases 13(8): 1184-1188.

Return to footnote 17 Referrer

Page details

Date modified: