Norovirus outbreak resident survival guide

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Twinkle Singh, M.B.B.S. [2]


Norovirus is one of the extremely contagious viruses leading to 50% of the gastroenteritis outbreaks worldwide.[1] An outbreak of norovirus is defined as an occurrence of 2 or more similar illnesses resulting from a common exposure that is either suspected or laboratory-confirmed to be caused by norovirus.[2]

Prevention of Norovirus Outbreak

Shown below is an algorithm summarizing the approach to prevention and control of a norovirus infection outbreak according to recommendations by CDC.[3]

Before Cruising

❑ If you are sick before starting your cruise, consider alternative cruising options.

On the Cruise

Hand Hygiene

❑ Wash hands with soap and running water for 20 seconds.
❑ Hand sanitizers (with at least 60% alcohol) can be used as an adjunct to soap.
❑ Wash your hands:

❑ Before eating, drinking and smoking
❑ After visiting bathroom
❑ After changing diapers
❑ After touching things that other people might have touched

❑ Avoid touching your face.

❑ Do not touch any ready to eat foods with bare hands.
Food and water precautions

❑ Avoid eating raw fruits and vegetables unless they are washed and peeled by yourself.
❑ Avoid eating improperly cooked shellfish, oysters and clams.
❑ Prefer food which is cooked properly and served hot.
❑ Avoid ice.
❑ Safe beverages include:

❑ Bottled or canned water
❑ Bottled carbonated soda
❑ Hot tea, coffee, beer and wine
❑ Boiled water, or water which has been treated appropriately with chlorine
❑ Beverages from sealed containers
Isolation of infected people

❑ If you see someone getting sick, move away from the area and report to the cruise staff.
❑ Infected patients should be isolated during period of illness and up to 48-72 hours following recovery.

❑ Asymptomatic but norovirus positive food handlers should also be isolated.
Disinfection of the environment

❑ Clean contaminated surfaces to remove organic loads.
❑ Use freshly prepared 5000 ppm chlorine bleach solution.
❑ Apply disinfecting agent for up to 4 min on fecally soiled surfaces.
❑ Other disinfecting agents include:

❑ Ozone
❑ Hydrozen peroxide[4]

PPM: Parts Per Million


Shown below is an algorithm summarizing the approach to norovirus infection outbreak according to recommendations by CDC.[3]

Characterize the symptoms:
❑ Non bloody diarrhea
Abdominal cramps
Low grade fever
❑ Body aches
❑ Chronic diarrhea (in immunosuppressed)
Irritable bowel syndrome
Inquire about exposure to settings prone to outbreaks:

❑ Health care settings
❑ Restaurants
❑ Cruise ships

❑ Schools and other institutional settings
Laboratory tests can be done
Laboratory tests cannot be done
Collect samples
Assess The Kaplan criteria

Whole stool sample

❑ Within 48 to 72 hrs after onset
❑ From at least 5 ill patients
❑ 10-50 ml of whole stool sample in a stool cup
❑ If testing done < 3 weeks
❑ Refrigerate samples at 39 °F
❑ If testing done > 3 weeks
❑ Refrigerate samples at - 4 °F
❑ The specimens are bagged, sealed and transported on ice packs in an insulated and waterproof container.

Vomitus sample

Environmental samples:

❑ Water sample
❑ Shellfish samples
❑ Environmental surface swabs
❑ Mean duration of illness is 12-60 hours.

❑ Mean incubation period is 24-48 hours.
❑ Vomiting is present in more than 50% of ill people.
❑ No bacterial agent is found.

Diagnostic tests:

❑ Enzyme immunoassays (RIDASCREEN)
❑ Real time RT-PCR
❑ Geno-typing

❑ Electron microscopy
Are all 4 criteria present?
Norovirus negative
Norovirus positive
❑ Treat the acute gastroenteritis
Norovirus outbreak is highly likely
Norovirus outbreak is less likely but cannot be ruled out

Implement measures to contain the outbreak

❑ Isolate the infected patients and food handlers for a minimum period of 48 hours after recovery from symptoms.
❑ Disinfect routinely touched surfaces.
❑ Promote hand hygiene among people during an outbreak.
❑ Avoid any group activities.
❑ Notify local and state health departments.
❑ Activate outbreak prevention and response protocol (OPRP) on cruise ships as per CDC recommendations.
❑ Report the outbreak to National Outbreak Reporting System

RT-PCR: Reverse Transcription Polymerase Chain Reaction

Initial Management of Acute Gastroenteritis

Shown below is an algorithm summarizing the approach to initial management of acute gastroenteritis.

Assess the volume status
General conditionNormalIrritable/less active*Lethargic/comatose§
EyesNormalSunken -
MucosaNormalDry -
ThirstNormalThirstyUnable to drink§
Radial pulseNormalLow volume*Absent/ uncountable§
Skin turgorNormalReduced -

† Some dehydration = At least two signs, including at least one key sign (*) are present.

‡ Severe dehydration = Signs of “some dehydration” plus at least one key sign (§) are present.
No dehydration
Some dehydration
Severe dehydration
❑ Start altered diet
❑ Stop lactose products
❑ Avoid alcohol and high osmolar supplements
❑ Drink 8-10 large glasses of clear fluids (fruit juices, soft drinks etc)
❑ Eat frequent small meals (rice, potato, banana, pastas etc)
❑ Consider starting ORT for replacement of stool losses
❑ Start ORT at a volume of 50-100 mL/kg
❑ Start altered diet
❑ Reassess the patient's status every 4 hours
❑ Order CBC
❑ Order electrolytes
❑ Start IV fluids with Ringer lactate at 30ml/kg in the first 1/2 hour and 70ml/kg for the next 2 and 1/2 hour, if unavailable use normal saline
❑ Assess status every 15 mins until strong pulse felt and then every 1 hour
When the patient is stable and able to drink:
❑ Start ORT at a volume of 100 mL/kg over 4 hour
❑ Calculate the continuing stool and emesis losses every hour for additional maintenance ORT therapy
❑ Reassess status every 4 hours

CBC: Complete Blood Count; ORT: Oral replacement therapy


  • Consider an outbreak of norovirus when norovirus is positive in stool or vomitus specimens from 2 or more patients are found to be positive for norovirus by RT-PCR, EIA or electron microcopy.


  • Do not obtain serum samples for routine norovirus detection.
  • Do not use hand sanitizers as a substitute for washing hands with soap and water.


  1. Patel MM, Hall AJ, Vinjé J, Parashar UD (2009). "Noroviruses: a comprehensive review". J Clin Virol. 44 (1): 1–8. doi:10.1016/j.jcv.2008.10.009. PMID 19084472.
  2. "CDC - Norovirus - Reporting and Surveillance for Norovirus". Retrieved 10 February 2014.
  3. 3.0 3.1 Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention (2011). "Updated norovirus outbreak management and disease prevention guidelines". MMWR Recomm Rep. 60 (RR-3): 1–18. PMID 21368741.
  4. "" (PDF). Retrieved 10 February 2014. External link in |title= (help)

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