Noroviruses

Marion CountyPublic Health Department

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

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

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

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

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

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

Immunity Limited immunity, may be strain

specific and last only a few months Can recur throughout a person’s

lifetime Some people are more likely to

become infected and develop more severe illness than others Example: people with O blood group most

susceptible

Critical Characteristics Highly contagious Multiple modes of transmission Stable in the environment Resistant to routine disinfection

methods Asymptomatic infections Limited immunity

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

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

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.

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

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

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

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

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

Cleaning Specific Things Frequently clean hand contact

surfaces, e.g. door handles, railings, tabletops, etc. with bleach solution

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

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

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

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.

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

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

Gastroenteritis Outbreaks in Marion County for 2006

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UnknownNorovirus

Gastroenteritis Outbreaks in Marion County 2007

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Jan March May July Sept Nov

UnknownNorovirus

Gastroenteritis Outbreaks in Marion County 2008

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UnknownNorovirus

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

                                                                                                                                         

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

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.

Outbreak Declared Over

Seven days must pass without new cases before an outbreak of

Norovirus-like gastroenteritis is declared over

Partnership with other agencies Reinforcing the same control

measures Building continuity of care Promoting communication

between the health department and other agencies

Sources

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