Noroviruses

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Noroviruses

• Marion County
• Public Health Department

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What are noroviruses?

• Group of viruses that cause the stomach flu, or
  gastroenteritis
• The term norovirus was recently approved as the
  official name for this group of viruses.
• Approximately 23 million cases each year in U.S.
• Leading cause of outbreaks of gastroenteritis

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Symptoms

• Nausea, vomiting, diarrhea, abdominal cramps
• Sometimes low-grade fever, chills, headache,
  myalgia, fatigue
• Often begins suddenly, and the infected person
  may feel very sick

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Incubation, Duration, Communicability

• Incubation period 12 - 48 hours (median in
  outbreaks is 33 - 36 hours)
• Duration of illness 24 - 60 hours
• Period of communicability onset through 72 hours
  after recovery

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Transmission

• Found in the stool and vomit of infected people
• Infective dose as few as 100 viral particles
• Can be transmitted several ways
• Eating food or drinking liquids that are
  contaminated with norovirus
• Direct person-to-person spread
• Airborne and fomite transmission in droplets
  contaminating surfaces or entering the mouth and
  being swallowed

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How serious is it?

• Usually not serious, although people may feel
  very sick and vomit many times a day
• Most get better within 1 or 2 days, and they have
  no long-term health effects related to their
  illness
• Can be serious for the very young, the elderly,
  and persons with weakened immune systems due to
  dehydration

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Treatment

• Drink plenty of fluids to prevent dehydration
• No antiviral medication
• No vaccine to prevent infection
• Cannot be treated with antibiotics because
  antibiotics work to fight bacteria and not viruses

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Immunity

• Limited immunity, may be strain specific and last
  only a few months
• Can recur throughout a persons lifetime
• Some people are more likely to become infected
  and develop more severe illness than others
• Example people with O blood group most
  susceptible

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Critical Characteristics

• Highly contagious
• Multiple modes of transmission
• Stable in the environment
• Resistant to routine disinfection methods
• Asymptomatic infections
• Limited immunity

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Definition of a Gastroenteritis Outbreak

• An outbreak is a higher number of ill cases above
  baseline
• 2-3 ill cases with vomiting or diarrhea at a
  facility maybe a signal that an outbreak is
  starting
• Facilities are required by law to report any
  suspected outbreak of disease and are permitted
  to provide information on illnesses per HIPAA

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Hand Washing

• After using restrooms and before eating
• Before and after direct contact with residents
• Hand wash sinks have warm water, soap, and paper
  towels
• Alcohol-based hand sanitizer to supplement hand
  washing

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Hand washing is the single most important
practice to prevent the spread of outbreaks!

• HANDS MUST BE WASHED
• Whenever they are visibly soiled or there has
  been contact with stool.
• Between contact with different residents.
• Before putting on gloves and after removing
  gloves.
• After using the toilet.
• Before eating or smoking.
• Before handling or preparing food.
• A PROPER HAND WASH INCLUDES
• Using warm running water and soap with plenty of
  friction for 20 seconds.
• Using a clean paper towel to dry your hands and
  to turn off the tap.
• Use of a waterless hand sanitizer may be
  substituted for hand washing only if adequate
  sink facilities are not immediately accessible
  and hands are not visibly soiled.

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General Staff Guidelines

• Educate regular and agency staff about infection
  control practice
• Eliminate floating staff from affected to
  unaffected areas
• Notify supervisor immediately if ill
• Furlough ill staff for 72 hours after symptoms
  resolve
• Ill food service workers and servers should not
  prepare or handle food

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General Staff Guidelines

• Wear gloves, gowns, and mask during contact with
  ill residents
• Pairing employees who have recovered from the
  illness with currently ill residents
• Exclude non-essential personnel

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Residents and Visitors

• Recommend no new admissions
• Confine ill residents to rooms until 72 hours
  after symptoms resolve
• Place ill resident on contact precautions
• Cancel group activities (dining room)
• Do not transfer residents from affected areas to
  unaffected areas
• Post signs to inform visitors of outbreak
• Do not allow children to visit

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What can happen if the dining room is not closed?
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General Cleaning Principles

• Wear disposable gloves, gowns, and mask when
  cleaning up vomit or diarrhea
• Clean soiled areas with detergent and hot water
  first
• Always clean with paper towels or disposable
  cloths and dispose in infectious waste bags.
• Disinfect with freshly-made (daily) bleach
  solution of 1/2 cup of 6 household bleach to one
  gallon of water

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Cleaning Specific Things

• Increase routine cleaning
• Contaminated hard surfaces soak up excess liquid
  with paper towels, thoroughly clean with hot
  water and detergent, and disinfect with a bleach
  solution
• Contaminated carpets soak up excess liquid with
  paper towels, clean with hot water and detergent,
  then disinfect with bleach solution (if
  bleach-resistant) or steam clean

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Cleaning Specific Things

• Frequently clean hand contact surfaces, e.g. door
  handles, railings, tabletops, etc. with bleach
  solution

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Virkon Disinfectant

• Potassium peroxymonosulfate and Sodium chloride
  (equivalent to 9.75 available chlorine)
• Currently available Wilco Farm Stores
• Check Marion County Health website
  http//health.co.marion.or.us/ph/epid

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Laundry Staff

• Wear disposable gloves, gowns, and mask when
  handling contaminated laundry
• Maintain separate bins for dirty and clean
  laundry
• Place contaminated laundry in impermeable bags
  for transportation to laundry room

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Kitchen Staff

• Furlough ill staff for 72 hours after symptoms
  resolve. After returning to work, restrict from
  handling kitchenware and ready-to-eat food for
  another 72 hours
• Double hand wash after using restroom, eating,
  breaks
• Use single-use gloves in addition to hand washing
• Limit access of bin-style ice machine to kitchen
  staff
• Keep food covered when transporting
• Discard any food handled by an infected worker
• Disinfect food prep areas with bleach solution

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Vomiting Incidents in the Kitchen

• Carefully remove all visible vomit.
• Disinfect food preparation area with ½ cup of
  bleach to one gallon of water.
• Discard exposed food or single-serve articles
  within a 25-foot radius of the incident.
• Food contact surface disinfection should be
  followed with a clear-water rinse and a final
  wipe down of 1 tablespoon of bleach to one gallon
  of water.

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Dining

• Post signs encouraging hand washing before eating
• Discontinue self-service salad bars, family style
  dining, communal fruit bowls
• Provide alcohol-based hand sanitizer to
  supplement hand washing

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Public Restrooms

• Discourage use when possible
• Clean frequently using a freshly made bleach
  solution of 1/2 cup of 6 household bleach to one
  gallon of water

Bleach
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Gastroenteritis Outbreaks in Marion County for
2006
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Gastroenteritis Outbreaks in Marion County 2007
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Gastroenteritis Outbreaks in Marion County 2008
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Marion County Health Department Follow Up

• Collecting data on Gastroenteritis Case Log until
  Norovirus is identified
• Collecting stool samples
• Putting control measures into place for staff,
  residents, volunteers, and visitors
• Site visit by Environmental Health
• Working with Oregon Health Division
• Daily monitoring of outbreak

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• Addition information and forms on MCHD website
  http//health.co.marion.or.us/ph/epid

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Collecting Stool Specimens

• 5-6 stools from ill or recently ill resident and
  staff.
• Collect stool specimen, the size of a walnut in a
  clean container with a lid.
• Label container with name, dob, and date
  collected.
• Refrigerate until specimen can be brought in to
  the health department.

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Outbreak Declared Over

• Seven days must pass without new cases before an
  outbreak of Norovirus-like gastroenteritis is
• declared over

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Partnership with other agencies

• Reinforcing the same control measures
• Building continuity of care
• Promoting communication between the health
  department and other agencies

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Sources

• Robert E. Wheeler, MD, FACEP. Voyager Medical
  Seminars

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