Understanding Norovirus PHN ITV October 17, 2013 T.J. Sugg, MPH

1. Understanding Norovirus PHN ITV October 17, 2013 T.J. Sugg, MPH

2. Objectives • Describe the epidemiology and clinical features of norovirus (NoV). • Discuss LHD and KDPH response to NoV outbreaks • Discuss surveillance strategies for NoV • Describe NoV prevention and control measures • Describe a NoV outbreak that occurred in KY • Describe the emergence of the GII.4 Sydney NoV

3. Epidemiology and Clinical Features

4. Norovirus • Single-stranded RNA virus • Calciviridaefamily • Two human genera: noroviruses and sapoviruses • Six genogroups (I through VI) • I, II, and IV affect humans • 35 genotypes • Hundreds of different strains • Also known as: • Norwalk-like viruses • Stomach flu / 24-hour flu (misnomers – not influenza) • Winter time vomiting disease

5. Genetic Classification of NoV

6. NoV Disease Burden in the United States

7. NoV Incidence

8. Clinical Disease • Incubation period: 12-48 hours • Acute onset vomiting and/or diarrhea • Watery, non-bloody stools • Abdominal cramps, nausea, low-grade fever • Most recover after 12-72 hours • 10-12% seek medical attention; some require hospitalization and fluid therapy • Severe disease occurs more frequently among older adults, young children, and immunocompromised patients • More severe illness and death possible in elderly and those with other illnesses • 30% of infections are asymptomatic

9. Viral Shedding • Primarily in stool, but also in vomitus • Occurs for at least 2-3 weeks • Peaks 4 days after exposure • 1010 viral copies/gram of feces • May persist after symptoms resolve • Infectious dose: 18 to 1,000 viral particles • A droplet of vomitus has enough viral particles to infect over 100,000 people • NoV can survive 12 hours on a surface, 12 days in contaminated fabric. A study demonstrated survival for 61 days in well water.

10. Transmission • Person to person • Direct fecal-oral • Ingestion of aerosolized vomitus • Indirect via fomites or contaminated environment • Food • Contaminated by infected food handlers • Point of service or source (e.g., raspberries, oysters, leafy vegetables) • Recreational and Drinking Water • Well contamination from septic tank • Chlorination system breakdown • In healthcare, most likely from direct contact with infected persons or contaminated equipment

11. Transmission Cycle

12. Laboratory Confirmation • RT-PCR is preferred method for diagnosing NoV. KDPH Division of Laboratory Services (DLS) has this capability. • During outbreaks, KDPH and DLS request only 7-10 specimens to confirm the existence of a NoV. • Stool specimens should be collected during acute phase of illness. • Vomitus may be submitted for testing, but stool is preferred • Packaging and shipping instructions available on DLS website: http://chfs.ky.gov/NR/rdonlyres/0C2947A7-D115-4846-B133-B565DFDEBA57/0/norovirus2013.pdf

13. Immunity • Short-term immunity after infection • Little cross protective immunity • No long-term immunity • Protection believed to be less than a year. Some studies suggest only a few months • Genetic susceptibility • Some may be resistant to NoV infection • No commercially available test to identify those who might carry genes conferring resistance to NoV infection

14. Vaccine • Intranasal vaccine • Safe and immunogenic • 47% effective against NoV gastroenteritis • Bivalent GI.1/GII.4 vaccine currently being tested in human volunteers

15. Surveillance

16. National Outbreak Reporting System (NORS) • Comprehensive national surveillance system for all US outbreaks • Launched in February 2009 • Helps to assess the national burden and temporal trends of outbreaks • Aids in identifying priority settings and population for interventions • Assists in characterizing outbreaks • Pathogen • Setting • Mode of transmission

17. Calcinet • Molecular NoV genotyping network (Similar to PulseNet) • Data shared between public health labs and CDC • Links outbreaks and identifies common sources • Identifies emergent variants • Implemented March 2009

18. NoV Sentinel Testing and Tracking (NoroSTAT) • Select state health departments participate in this network (MN, OH, OR, TN, WI) • States report suspected NoV outbreaks through NORS and CalciNet within 7 business days of notification of the outbreak to the health department. • Allows NoV strain data uploaded through CalciNet to be rapidly linked with epidemiologic characteristics of outbreaks reported through NORS

19. LHD Quick Reference Guide for NoV Outbreaks

20. Reporting • Jasie Logsdon, MPH, MA is the foodborne and waterborne disease epidemiologist and serves as the primary point of contact for NoVoutbreak reporting. • KDPH is in the process of updating guidance for responding to NoV outbreaks in various settings within the community, including jails, schools, long-term care facilities (LTCF), assisted living facilities, and other healthcare or residential facilities, such as independent living facilities, residential care facilities for the developmentally disabled, acute care, transitional care, and rehabilitation units.

21. Reporting Continued • Outbreaks of NoV should be reported to the local health department within the jurisdiction in which the outbreak is occurring or KDPH immediately upon recognition of the outbreak.

22. LHD Quick Reference Guide for NoV Outbreaks • Notify KDPH RDS of potential outbreak • Establish a working case definition • The three 3’s • 3 days per incubation period • Up to 3 days exclusion for employees after symptoms have resolved • At least 3 positive specimens to confirm outbreak • Encourage and review proper hand washing

23. LHD Quick Reference Guide for NoV Outbreaks • Cleaning and disinfecting surfaces: • Particular attention to high-touch surfaces • Clean, then disinfect surfaces • Use a chlorine bleach solution (5.25%; 25 tablespoons bleach per gallon of water) for hard, nonporous surfaces or disinfectants registered as effective against NoV by EPA • Prepare fresh dilution of bleach every day and discard unused portions

24. LHD Quick Reference Guide for NoV Outbreaks • Recommend that ill staff members in health-care facilities and food handlers be excluded during acute illness and for 72 hours following resolution of symptoms • Recommend use of contact precautions (gown, gloves, and surgical mask) • Avoid cross-coverage of staff members between units or facilities with affected patients • Cohort symptomatic patients when possible • Contacts of symptomatic patients should be monitored for symptoms

25. LHD Quick Reference Guide for NoV Outbreaks • Recommend the facility have signs on all entrances about the outbreak • Cancel or postpone group activities • Recommend that the facility close to new admissions for 2 incubation periods (6 days) after the last onset of symptoms among residents and staff. • Collect stool specimens on 7 to 10 ill patients or staff. Contact KDPH RDS for coordination of testing with DLS. • Enter data into NORS (Regional Epidemiologists)

26. LHD Quick Reference Guide for NoV Outbreaks • When transferring symptomatic patients, notify EMS and the hospital or the receiving facility in advance • Conduct a site visit with environmentalist and/or obtain a diagram of the facility layout • Kaplan Criteria for outbreak determination if no specimens are available: • A mean (or median) illness duration of 12-60 hours • A mean (or median) incubation period of 24-48 hours • More than 50% of people with vomiting, and • No bacterial agent found

27. Prevention and Control

28. Where hands go…go Noro • Practice proper hand hygiene • Wash hands with soap and water • Especially after using the toilet and changing diapers • Always before eating, preparing, or handling food • Stay at home if you are ill

29. Food Preparation • Wash fruits and vegetables before preparing and eating them • Cook oysters and other shellfish thoroughly before eating them • Food that might be contaminated with NoV should be thrown out • Keep sick infants and children out of areas where food is being handled and prepared • When sick, do not prepare food or care for others for at least 72 hours after symptoms subside

30. Environmental Control • Clean and disinfect contaminated surfaces • After vomiting or having diarrhea, immediately clean and disinfect contaminated surfaces. • If a sick individual has been in food preparation areas, all surfaces should be cleaned and disinfected. • Use a chlorine bleach solution (5-10% solution) or other disinfectant registered as effective against NoV by EPA • Wash laundry thoroughly • Immediately remove and wash clothes or linens that may be contaminated with vomit or stool • Handle soiled items carefully without agitating them • Wear rubber disposable gloves and wash hands afterward • Wash items with detergent at the maximum available cycle length then machine dry them

31. Controlling NoV in Food Service • Handwashing • Prohibiting bare-hand contact with ready-to-eat (RTE) food items • Removing food service workers with active vomiting and/or diarrhea • Restricting recently ill food service workers for 72 hours after symptoms subside • Sanitizing

32. No Bare-Hand Contact with RTE Foods • Use of utensils (i.e., gloves, papers, tongs, etc.) • Educate workers on proper use • Choosing the proper utensil • Glove integrity • When to change/how to change gloves

33. Employee Health Program • Communication is a key element • Educate food service workers on hazards of vomiting and diarrhea • Work as a team to find innovate ways to keep ill food service workers out of the restaurant • Inform food service workers that they must report GI symptoms to the person in charge • Report GI symptoms • Comply with strict handwashing requirements • Comply with no-bare hand contact requirement • Use teachable moments

35. KY NoV Outbreak at a Youth Basketball Tournament

36. Background • February 3-5, 2012 • 7th grade boys basketball tournament • Lexington, KY • Statewide tournament • 52 schools • >600 players

37. Methods • Identify cases • Basketball coaches • Absentee data from schools • Employees • Standard case report form • Illness history • Food and water exposures • Stool samples required for testing

38. Case Definitions • Probable case • Vomiting or diarrhea in a tournament attendee • Onset within 72 hours of attendance • No laboratory confirmation of norovirus • Confirmed case • Probable case with stool specimen positive for norovirus by real-time reverse transcription-polymerase chain reaction (RT-qPCR)

39. Basketball Teams

40. Identified Cases

41. Results • No common food or water exposure • 6 (100%) stool specimens tested positive for norovirus • Genogroup II type 7 (GII.7) • Confirmed cases were from 4 different teams

42. Cases of Acute Gastroenteritis, by Data of Onset Tournament Dates

43. Cases of Acute Gastroenteritis, by Data of Onset Tournament Dates

44. Cases of Acute Gastroenteritis, by Data of Onset Tournament Dates Vomiting Episode

45. Cases of Acute Gastroenteritis, by Data of Onset Tournament Dates Vomiting Episode

46. Conclusions • NoV caused an outbreak of acute gastroenteritis at a basketball tournament in KY • Person-to-person transmission • Public vomiting episode • Contaminated environmental surfaces

47. Public Health Recommendations • Exclusion of players with gastroenteritis symptoms within 24 hours • Increased education on personal hygiene • Clean and disinfect environmental surfaces

48. Emergence of GII.4 Sydney Norovirus, United States, 2012-2013

49. GII.4 Sydney • New NoV strain identified in March 2012 • Caused acute gastroenteritis outbreaks in New Zealand, Japan, Western Europe, Canada, and the United States • Became the predominant NoV strain implicated in outbreaks

50. GII.4 Sydney Incidence • From Aug 1, 2012 – April 16, 2013, 637 NoV outbreaks were reported by MN, OH, OR, TN, and WI. • Cumulative number of outbreaks increased in 3 states (OR, TN, and OH) compared to the previous two seasons • Peak activity occurred in January 2013 and was 16% higher than the average peak month outbreak activity in the 2 preceding seasons • Season duration was 21 weeks in 2012-13 compared to 18 weeks in 2011-12 and 22 weeks in 2010-11