Multi-County Salmonella Outbreak Associated with a Chain Restaurant Summer 2009

1. Debra Ellison RS, Regional Epidemiologist Suzanne Wilson, MPH, Food & Waterborne Disease Epidemiologist Multi-County Salmonella Outbreak Associated with a Chain RestaurantSummer 2009

2. Objectives Discuss the epidemiology of the outbreak Discuss the environmental assessment Discuss the steps taken during the investigation Discuss the statistics and outcome of the investigation

3. 13 Steps to an Outbreak • Step 1: Prepare for field work. • Step 2: Establish the existence of an outbreak • Step 3: Verify the diagnosis • Step 4: Construct a working case definition • Step 5: Find cases systematically and record information • Step 6: Perform descriptive epidemiology

4. Step 7: Develop hypotheses. • Step 8: Evaluate hypotheses epidemiologically. • Step 9: As necessary, reconsider, refine and re-evaluate hypotheses • Step 10: Compare and reconcile with laboratory and/or environmental studies • Step 11: Implement control and prevention measures. • Step 12: Initiate or maintain surveillance • Step 13: Communicate findings.

5. Background Salmonella enteritidis Approximately 40,000 Salmonella human clinical isolates each year >2500 serotypes of Salmonella Enteritidis is the 2nd most common serotype of Salmonella reported to CDC Outbreaks historically associated with eggs and poultry products

6. Suspicious Activity • June 12 – 5 cases recognized in 2 counties • June 15-20 – Cases continue • 4 cases noted by DIDE and CAMC ICP • Cases were from different counties • June 23-27 - The work begins • A total of 18 cases of Salmonellaidentified in 6 counties

7. Establish the existence of an outbreak • General definition: number of cases over and above the expected number in a given timeframe • Foodbornedisease outbreak is defined as two or more persons who experience a similar illness after ingestion of a common food. Please note two exceptions: one case of botulism or chemical poisoning constitutes an outbreak.

15. Find cases systematically and develop a line listing • WVEDSS can be helpful • All Salmonellacases entered on or after May 25, 2009 were searched and placed in Excel spreadsheet • Data included • Age • Race • Gender • Symptoms • Onset of illness • Patient address • Activities • Survival • Hospital • Serotype • Restaurants (location) • Notes

16. Construct a working case definition Suspect– Case of Salmonellosis with onset after May 25, 2009 in Logan, Cabell, Wayne, Lincoln, Boone, or Putnam counties for which PFGE testing is pending. Confirmed- Case of laboratory confirmed Salmonella Enteritidiswith onset of illness after May 25, 2009 AND PFGE pattern Xba- JEGX01.wv001 and Bln- JEGA26.wv001 Probable– Case of diarrheal illness with onset after May 25, 2009 and is epidemiologically linked to a confirmed case

17. It’s Established … now the issues • Verify the diagnosis - Salmonella enteriditis • Issues • the most common subtype in WV • Multiple counties • Multiple interview techniques • Patient recall • 2 deaths • No “common” risk factors

18. No “common” risk factors until… • Restaurant X starts to appear in the case reports • Issues • Chain restaurant – not all from the same location • Onset dates are random when looked at as whole • However when looked at by location…

19. Location of Cases and Identified Restaurants Purple – ate at Wayne location Green – ate at Eleanor location Yellow- ate at Chapmanville location Blue - ate at Danville location Red - Restaurant White – cases that did not indicate eating at any restaurant location

20. Onset Dates by Restaurant X Location (N=13)

21. Now What?

22. Shotgun questionnaire • Administered to 7 cases • Included general food information • Included eating and shopping venues • Restaurant types

23. Attack rates from Shotgun Questionnaires (N=7) Various Restaurants Attack rate = # with exposure / # total responses

24. Attack rates from Shotgun Questionnaires (N=7) Various Food Items Attack rate = # with exposure / # total responses

25. The Plan – Next Steps • Additional lab testing • MLVA analysis at CDC • Further analytic study • Case control and cohort studies • Conduct environmental risk assessments

26. The Investigation(Methods/Results) A restaurant case control study was undertaken using “friend controls”. • 14 cases and 34 controls were included • Questioned about eating at 11 different area restaurants • Restaurant X had an odds ratio of 5.92 (CI 1.39-25.30, p<0.01)

27. The Investigation(Methods) Anyone responding “yes” to Restaurant X was enrolled in cohort to implicate food items Total of 11 cases and 13 controls Focus on breakfast items

28. Food Cohort Results

29. Laboratory Results • PFGE analysis (OLS) • All 19 isolates are 2 enzyme match • MLVA analysis (CDC) • 2 related patterns • corresponded to location of Restaurant X exposure

30. Outbreak Timeline

31. Outbreak Timeline

32. Outbreak Timeline

33. Outbreak Timeline

34. Age Distribution

35. General Statistics (21 cases) • Gender – 10 females (48%) 11 males (52%) • Hospitalized – 9 cases (45%) • Deaths – 2 • Underlying Medical Condition – 5 cases (25%)

36. Implement control and prevention measures • What control measures can be implemented?

37. Risk Assessment vs. Inspection • Inspections • Evaluate food workers' practices • Hand hygiene • Evaluate food processes • Storage, temperature control etc. • Risk Assessment • Focuses detailed observations on a food item • “Trailer to Trash”

38. The Environmental Side • Restaurant X locations, • 4 main locations all in different counties • EH staff from each county health department conducted an inspection of each facility • Multiple opportunities for cross contamination found • problems with cold holding • inadequate cooking temperatures • no temperature checks • no ill food handlers at any of the facilities

39. Restaurant X • Full cooperation from all 4 restaurant X locations owners/managers and CEO of Chain • product samples taken from the 4 locations • tested negative for Salmonella at OLS • Lot numbers were a problem • US Food Service distributor of sausage • was unable to provide detailed information as to the lot #s of sausage received at each location.

40. In the end • 21 cases • 19 confirmed, 2 probable • 2 deaths associated with Salmonella • Spanned 7 counties • Onset dates ranged 5/26 to 7/3 • Sample testing – provided negative results on suspect food • 4 locations were inspected

41. Counties involved: • Logan (8 cases) • Putnam (4 cases) • Cabell (2 cases) • Boone (1 case) • Wayne (4 cases) • Lincoln (1 case ) • Fayette (1 case)

42. Limitations Number of controls in case-control study Unable to obtain lot numbers of sausage Implicated lot(s) not available for testing No positive sample obtained-no USDA traceback Commonality of PFGE pattern prevented identification of cases in other states Incomplete case detection Resource limitations

43. Conclusions Lot(s) of sausage contaminated with Salmonella delivered to the 4 locations Inadequate cooking of sausage Cross contamination

44. Acknowledgements • WVDHHR-Office of Epidemiology & Prevention Services • Loretta Haddy • Danae Bixler • Maria del Rosario • Lillie Clay • Alana Hudson • Rachel Radcliffe • WVDHHR-Office of Laboratory Services • Christi Clark • Megan Young • WVDHHR-Office of Environmental Health Services • Ryan Harbison • Jessica Douglas • Linda Whaley Boone County Health Department Julie Miller Sandra Giles Cabell County Health Department Kim Lockwood Fayette County Health Department Nora Smith Logan County Health Department Sherry Adams Steve Browning Putnam County Health Department Barbara Koblinsky Wayne County Health Department Melissa Spence Dave Farley

45. Questions