Noroviruses

1. Noroviruses Marion County Public Health Department

2. 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

3. 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

4. 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

5. 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

6. 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

7. 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

8. 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

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

10. 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

11. 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

12. 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.

13. 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

14. 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

15. 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

16. What can happen if the dining room is not closed?

18. 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

19. 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

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

21. 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

22. 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

23. 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

24. 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.

25. 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

26. 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

27. Gastroenteritis Outbreaks in Marion County for 2006

28. Gastroenteritis Outbreaks in Marion County 2007

29. Gastroenteritis Outbreaks in Marion County 2008

31. 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

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

33. 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.

34. Seven days must pass without new cases before an outbreak of Norovirus-like gastroenteritis is declared over Outbreak Declared Over

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

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