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CONTROL OF NOROVIRUS

CONTROL OF NOROVIRUS. Prepared by Erva -Jean Stevens (PhD Candidate) Walden University Environmental Health October, 2010. Outline. Objectives What is Norovirus Transmission of norovirus Signs and symptoms Characteristics of norovirus Case study - presentation of cases

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CONTROL OF NOROVIRUS

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  1. CONTROL OF NOROVIRUS Prepared by Erva-Jean Stevens (PhD Candidate) Walden University Environmental Health October, 2010

  2. Outline Objectives What is Norovirus Transmission of norovirus Signs and symptoms Characteristics of norovirus Case study - presentation of cases - preliminary investigations

  3. Outline cont’d -laboratory findings - management and control - challenges - outcome • Control – prevention of transmission • Barriers to effective control • Control • References

  4. Objectives of presentation Explain the transmission of norovirus Present a real case scenario Outline the management and control of norovirus Present the challenges faced in the control of norovirus Present prevention strategies

  5. What is norovirus? Norovirus is a single stranded non enveloped RNA virus belonging to the family Caliciviridae Norovirus, previously called Norwalk-like virus from a gastroenteritis outbreak in Norwalk, Ohio in 1968 Norovirus is reported as the single most common cause of gastroenteritis in the western world. CDC (2010). Technical fact sheet on norovirus. http://www.cdc.gov/ncidod/dvrd/revb/gastro/norovirus-factsheet.htm

  6. What is norovirus (contd) Over 21 million cases of norovirus infections each year Accounts for more than 50% of total reported food borne illnesses Among 232 outbreaks reported 1997-2000 57% transmitted through food 16% transmitted through person to person contact 3% waterborne 23% undetermined

  7. Transmission of Norovirus Fecal oral route - Contaminated food - Person to person - Water - Environment to person Droplets from vomit

  8. Signs and Symptoms Diarrhoea Vomiting Fever Abdominal cramps Up to 30% may be asymptomatic Duration – 1-2 days

  9. Characteristics of Norovirus Seasonal virus Highly infectious (10-100 dose of viral particles) Low virulence Resistant to routine disinfection measures Shedding begins with onset of symptoms and continue for 2 or more weeks after recovery

  10. Disease Process Timeline Clinical illness Infection Incubation Period Asymptomatic Symptomatic EXCRETION OF AGENT 0 1 2 3 4 5 6 7 8 9 10 11 12 13 TIME IN DAYS Exposure Onset of Symptoms End of Symptoms

  11. Case Study

  12. Case study February 6, 2005 – Hotel X notifies the health department of the following: - endemic level for GE exceeded - gift shop reported large numbers of guests purchasing Imodium - food history revealed no clear association for person, place and time

  13. Results-preliminary investigation Case definition: Guests or staff who ate at least one meal at Hotel X between February 14 and 21, 2005 and had diarrhea with or without other symptoms 14 cases identified Signs and symptoms included diarrhea, fever, vomiting, nausea, dehydration No significant association between cases and food consumed Attack rate for Block X was the highest (32%)

  14. Initial action taken • Complete assessment done of all food preparation areas • Report with recommendation issued to hotel • Composite egg samples sent to the lab • Stool specimen sent to the lab • History collected for controls

  15. Results – overall investigation • Case definition expanded • 35 guests and 14 staff were affected • Epi curve indicated that guests were sick first • Index case identified with guest room that was previously implicated in an outbreak • Many repeat rooms were identified • Infection spread to the community (1 hospitals and 2 schools) • 8 persons in the community were affected

  16. Overall Action/Outcome • Intensified investigation • Case definition changed to incorporate gastro intestinal cases • Guests quarantined • Sick staff sent home • Environmental samples sent to lab • Swimming pools drained • HOTEL ORDERED CLOSED

  17. Challenges for health team No prior history of norovirus hence investigation was not focused on this pathogen Delays in laboratory analyses of the specimen as norovirus testing is only available at the central lab and the testing kits were not readily available Reluctance of hotel guests on holidays to adhere to quarantine procedures

  18. Challenges for the hotel managerial team Delay in decision by management to: isolate staff who were showing symtoms adhere to cleaning and disinfecting protocols for norovirus in guest rooms and public areas close swimming pools as requested by the health team

  19. Challenges (Cont’d) Close infected rooms were not always closed for 72hrs and were rented as soon as sick guests checked out. Specific teams were not assigned to affected rooms Public accidents were not addressed according to guidelines.

  20. Outcome The following outcomes resulted Mean duration of illness was 2 days Control measures delayed possibly resulting in spread to the community Training of hotel staff Public education in schools Ongoing surveillance for norovirus

  21. Control

  22. Control norovirus- prevent transmission • Good worker hygiene • Hand washing • Prohibiting bare hand contact with ready-to-eat food items • Removing sick food workers • Environmental cleaning and sanitation • Management attention CDC (2010). Technical fact sheet on norovirus. Qccessed at: http://www.cdc.gov/ncidod/dvrd/revb/gastro/norovirus-factsheet.htm

  23. Hand washing The first line of defense in the control of norovirus One of the most under-utilized defense strategy Hand sanitizers are not substitute for hand washing as alcohol based cleansers are impacted by soil, moisture, is neutralized by protein, and has limited effect on food borne viruses

  24. Handwashing Cont’d: Handwash Time: 20 Second Scrub Soap: surfactant effect in removing grease, soil, and debris from the hands. Water Temp: Soap efficacy is tested at ASTM Standards = 40°C +/- 2 degrees ~ (100°F - 107°F) Minimum water temp: 100°F

  25. HANDWASHING: Cont’d Every Stage of hand washing is Important Scrubbing w/ soap = 1 log virus reduction Rinsing hands under strong velocity & volume of running water - increased effect in removing transient viruses Drying hands = 1 log virus reduction

  26. No Bare Hand Contact Review food service practices to ensure no-bare hand contact with ready-to-eat foods including fruits, breads, and garnishes Use gloves, tongs, tissue, utensils Remember that employees can shed bacteria and viruses even when not symptomatic

  27. Remove sick workers Based on 4 Levels of Risk Based on infective period Balances employee’s needs with risk to the public Provides guidance on safely allowing infected employees to return to duties

  28. Environmental cleaning & disinfecting Reducing airborne transmission Treat contaminated material as infectious waste Cleaning Staff should use barriers, such as disposable face masks, gloves, shoes covering and aprons. Dispose of materials used to clean-up vomiting incident, and thoroughly disinfect the area (eg. Mop heads and wipe cloths)

  29. Norovirus disinfection Norovirus survives 0°C to 60°C Acceptable food heat treatment– Ultra High Pasteurization 56°C for 60 min., 70°C for 5 min., or 100°C for 1 min. for complete inactivation of the virus or 70°C for 3 min. for 6.5 log10 reduction Cruise Ship Industry uses chemical disinfection of carpets/ followed by steam cleaning: 70°C for 5 minutes

  30. Other disinfectants Glutaraldehyde 0.5% Iodine 0.8% Hypochlorite—Household bleach—1000 ppm

  31. Management supervision Review guidelines Ensure adherence to cleaning protocols Ensure continued training of staff Ensure adherence to quarantine guidelines

  32. Barriers to effective control Economic cost to the establishment Salary loss to staff Difficulty in isolating persons because of their movements in and out of the institution

  33. Conclusion Norovirus causes significant morbidity and economic loss. Attention to the different protocols for control can reduce the spread Early recognition and intervention will limit spread A team approach is necessary for control

  34. References CDC. (2010). Technical fact sheet on norovirus. Accessed 20/10/2010 at: http://www.cdc.gov/ncidod/dvrd/revb/gastro/norovirus-factsheet.htm Kaplan JE, Feldman R, Campbell DS, Lookabaugh C, Gary GW. The frequency of a Norwalk-like pattern of illness in outbreaks of acute gastroenteritis. Am J Public Health 1982;72:1329–32. Lillquist D., McCabe M.L., Church K.H., (2005). “A comparison of traditional hand washing training with active hand washing training in the food handler industry”. Journal of Environmental Health 67(6), 13-16.

  35. References Cont’d • Lopman BA, Adak GK, Reacher MH, Brown DWG. Two epidemiologic patterns of Norovirus outbreaks: surveillance in England and Wales, 1992-2000. Emerg Infect (2003). Available from: URL: http://www.cdc.gov/ncidod/EID/vol9no1/020175.htm • Ministry of Health (2008). Foodborne outbreak investigations – the norovirus experience. MOH • Stephens, R. (2007). Hand washing compliance in restaurants, St. Mary, Jamaica. (Unpublished)

  36. Further reading • CDC. Norovirus Outbreaks on Three College Campuses --- California, Michigan, and Wisconsin, 2008. MMR Weekly. Access at: http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5839a2.htm

  37. THANK YOUQuestions?

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