Foodborne Disease Outbreak Investigation Team Training:

1. Module 2 – Foodborne Disease Surveillance and Outbreak Detection Foodborne Disease Outbreak Investigation Team Training:

2. Module Learning Objectives At the end of this module, you will be able to • Describe the surveillance of foodborne illness through notification/complaint systems. • List ways to improve the accuracy of a food history obtained in a foodborne illness complaint. • Describe the surveillance of foodborne illness through pathogen-specific surveillance. • Recognize a possible outbreak using a notification/complaint system or pathogen-specific surveillance. • Describe the role of local public health in national pathogen-specific surveillance.

3. Foodborne Disease Surveillance • Many ways to find out about cases of foodborne illnesses and outbreaks • Two primary means • Foodborne illness notification/complaint systems • Pathogen-specific surveillance (notifiable disease reporting)

4. Foodborne Illness Notification/Complaint Systems

5. Notification/Complaint Systems • Complaints of illness among individuals and groups reported by affected members of the community (and others) • Includes any illness thought to be related to food • Common exposures are used to link cases together > Notifications/complaints

6.  Interview of complainant Evaluation of individual reports for immediate action Key information entered into log Evaluation of reports over time for outbreaks Routine review of log Steps in Receiving Complaints Illness in individual or group Starts with complaint by consumer Complaint to local health department Common exposures link cases over time Documentation of information > Notifications/complaints

7.  Interview of Complainant (e.g., name, age, and sex) • Who is affected? • What is the problem? • When did problem occur? • Where? • Why/how? (e.g., symptoms, diagnosis) (e.g., date/time of onset) (e.g., place of residence and exposure) (e.g., travel, water, contact with ill persons or animals, suspect food or meal, food history) Example in appendix > Notifications/complaints

8. Collecting Food Histories • Complete food history important including • Foods eaten in 5 days before onset of illness • If illness suggestive of norovirus, focus on 24-48 hours before illness. • If >1 ill person, focus on shared foods/meals. • ALL foods eaten during time period of interest (unless focusing on shared foods/meals) • Details of named events, food establishments, or suspect food products • Information on non-food exposures > Notifications/complaints

9. Small Group Exercise Divide into groups of two. One person will be the interviewer; one will be the complainant. The interviewer should solicit a 5-day food history from the complainant. The complainant should respond to questions as if they just developed symptoms that day and based on what they really ate in the last 5 days. Was it easy or difficult? Did you get a complete food history? What approaches were helpful? Be prepared to share your experience with the class. Time: 10 minutes

10. Improving Food Histories Have complainant • Look at a calendar • Describe each meal in time period • Identify key events to jog memory • Review receipts or menus • Enlist help of dining partners • Consider specific list of foods • Think about food preferences • Rule out or rule in specific foods > Notifications/complaints

11. Entering Information into Log • Extract key information from the complaint to facilitate examination of reports over time • Date of illness onset • Predominant signs and symptoms • Name of food thought to have caused illness • Names of eating places or gatherings • Source of water and type • Other exposures • Transfer information carefully • Use consistent abbreviations and codes > Notifications/complaints

12. Evaluation of Complaints • Individual reports of concern: • Symptoms suggestive of serious illnesses • Laboratory-confirmed diagnoses • Reports of obvious food safety problems • Group illnesses thought to be due to an identified, shared exposure > Notifications/complaints

13. Group Illnesses Due to Identified, Shared Exposure • Illnesses are likely to be related to an identified, shared exposure (e.g. particular meal, event, or establishment), if group members have: • Similar signs and symptoms • Shared a food or meal prior to onset of illness and had no other common exposures • Onset and nature of illness is consistent with identified shared exposure > Notifications/complaints

14.  Class Question Person developed diarrhea after eating at a restaurant. Neighbors who ate at the restaurant also are sick but complainant does not know their symptoms. Which of the following group illnesses are likely to be due to the identified restaurant exposure? Due to Exposure Unknown • Four friends develop nausea and vomiting, facial flushing, headache, and itching skin within an hour of eating fish at a restaurant. Likely Family members develop bloody diarrhea within hours of eating at a restaurant. Unlikely > Notifications/complaints

15. Evaluation of Complaints (cont’d) • Looking at reports over time • Multiple individual complaints with same exposure (e.g., same food establishment or food) • Multiple individual complaints with clustering by time, place, or person • Overall increase in complaints > Notifications/complaints

16. Response to Notifications/Complaints • Notify epidemiology unit/communicable disease staff of laboratory-confirmed diagnoses. • Refer food safety problem to agency with regulatory authority. • Alert appropriate persons if possible outbreak detected. • Prioritize follow-up of commercial establishments. > Notifications/complaints

17. Follow-up of Commercial Establishments Rational approach to follow-up • As required by local law/statute or • If complainant observed specific food safety problem or • If two or more persons (not from same household) • Have similar illness • Shared history of eating at establishment • Onset and nature of illness consistent with shared foods > Notifications/complaints

18. Group Exercise Divide into groups by table. Study the foodborne illness log at the end of this module spanning a 2-week period and determine: • Is the number of complaints what you would expect for the period covered? • Are there individual complaints of concern? • Are there common exposures (e.g. foods, establishments) across complaints signaling an outbreak? Be prepared to share your thoughts with the class. Time: 10 minutes

19. Strengths of Notification/Complaint Systems Primary means to detect outbreaks that are • Localized (involving only one jurisdiction) • Due to diseases with a short incubation period > Notifications/complaints

20. Notification/Complaint System Issues • Inaccurate and incomplete food histories • Large numbers of complaints • Anonymous complaints • Complaints with unknown causative agent • Inability to exclude unrelated cases • Inability to link cases based on illness unless symptoms very unique or cases report similar exposure > Notifications/complaints

21. Pathogen-specific Surveillance

22. Pathogen-specific Surveillance • Also called “reportable diseases,” “notifiable diseases,” or “laboratory-based reporting” • Reports of individual laboratory-confirmed cases of foodborne disease by medical and laboratory staff with submission of clinical isolates, where requested • Only covers diseases selected by public health agency • Cases linked to each other by common pathogen > Pathogen-specific

23.  Individual seeks health care Specimen collected Diagnosis by health-care provider/laboratory Submission of isolate to public health laboratory Initial report to health department Follow-up interview of case Further characterization Entry into electronic database Forward to CDC Analysis of cases for clusters/outbreaks Steps in Pathogen-specific Surveillance Illness in individual Starts with positive lab result Common pathogen links cases over time > Pathogen-specific

24. Initial Report • From health-care provider or laboratory • Standardized form (often pathogen-specific) • Information of interest • Patient identifiers • Basic demographic information • Clinical information • Laboratory results Example in appendix > Pathogen-specific

25. Follow-up Interview of Case • To identify potential exposures leading to illness • Similar to interview for notification/complaint system but tailored to specific pathogen • High-risk food exposures for agent • Other exposures related to agent (e.g., contact with ill people, animals, water) • Often occurs weeks after exposure leading to illness resulting in poor recall > Pathogen-specific

26. Laboratory Characterization of Pathogen • Submission of patient isolate to public health laboratory for confirmation and subtyping • Increased detail about the pathogen (e.g., serotyping, PFGE) improves • Recognition of clusters • Linking an outbreak with an exposure • Most critical with common pathogens > Pathogen-specific

27. Analysis for Clusters • Examine cases by pathogen over time using • Different levels of specificity of pathogen (e.g., species, selected subtypes) • Subgroups of population (certain time, place, or person characteristics) • Look for increase in number of cases over expected or baseline, indicating a cluster > Pathogen-specific

28. Analysis by Causative Agent Lab-confirmed salmonellosis cases by month of diagnosis, 2010. All Salmonella Number of Case Month of Diagnosis > Pathogen-specific

29. Analysis by Causative Agent Subtype Lab-confirmed salmonellosis cases by month of diagnosis All Salmonella Number of Case Salmonella Javiana Month of Diagnosis > Pathogen-specific

30. Analysis by Causative Agent and Age Group Lab-confirmed salmonellosis cases by month of diagnosis All Salmonella Number of Cases Salmonella Javiana among persons <5 yrs. Salmonella Javiana Month of Diagnosis > Pathogen-specific

31. Strengths of Pathogen-specific Surveillance Primary means to detect outbreaks that are • Wide-spread (i.e., multijurisdictional), • Due to prolonged low-level food contamination, or • Due to diseases with a long incubation (e.g., hepatitis A) > Pathogen-specific

32.  Pathogen-specific Surveillance Issues • Incomplete detection and reporting Reported Culture-confirmed Case Lab Tests for Organism Specimen Obtained Person Seeks Care Person Becomes Ill Population > Pathogen-specific

33.  Pathogen-specific Surveillance Issues Elapsed Time for Salmonella Reporting • Incomplete detection and reporting Patient eats food Incubation period=1-3 d Patient becomes ill Time to contact with health care=1-5 d • Elapsed time Stool sample collected Time to diagnosis=1-3 d Salmonella identified Shipping time=0-7 d Isolates received by public health lab Serotyping and PFGE=2-10 d Case confirmed as part of cluster > Pathogen-specific

34. Pathogen-specific Surveillance Issues • Incomplete detection and reporting • Elapsed time • Availability of isolate for further characterization > Pathogen-specific

35. Comparison of Surveillance Systems

36. National Pathogen-Specific Surveillance Systems

37. National Pathogen-specific Surveillance • NNDSS (National Notifiable Disease Surveillance System) • Data from pathogen-specific surveillance forwarded to CDC (minimal case information) • Statistical algorithm used to identify increases • PulseNet (National Molecular Subtyping Network for Foodborne Disease Surveillance) • Laboratory network that uses standardized pulsed field gel electrophoresis (PFGE) methods • PFGE patterns uploaded by labs for STEC, Salmonella, Shigella, Listeria, Campylobacter • Comparisons of patterns to identify clusters > National surveillance

38. National Pathogen-specific Surveillance • CaliciNet (National Electronic Norovirus Outbreak Network) • Laboratory network that subtypes/sequences norovirus isolates related to outbreaks • Data uploaded to CDC allows linkage of outbreaks and identification of new variants • NARMS (National Antimicrobial Resistance Monitoring System—enteric bacteria) • Submission of Salmonella, Shigella, E. coli O157, Campylobacter, and non-cholerae Vibrio to CDC • Determines trends in antimicrobial resistance > National surveillance

39. Role of Local Health Departments • Local pathogen-specific case reports and laboratory results feed into national surveillance • Important for local health departments to • Collect data in format consistent with other investigators. • Streamline reporting and isolate submission. • Share case reports with state and submit patient isolates to public health laboratory as quickly as possible. • Use national systems to learn about outbreaks in other jurisdictions. > National surveillance

40. 1 6 1 1 1 What difference does one local case make? • Two E. coli O157:H7 infections in MN with same PFGE pattern; both ate tenderized steaks • Through PulseNet, single cases identified in KS and MI; both ate tenderized steaks • Steaks eaten by cases from same plant • Recall of 739,000 lbs. of beef • Outbreak generated high levels of concern about needle/blade tenderized steaks > National surveillance

41. Quick Quiz

42. Quick Quiz • Typically common exposures are used to detect outbreaks through a foodborne illness notification/complaint systems whereas a common pathogen is used to detect outbreaks through pathogen-specific surveillance systems • True • False

43. Quick Quiz • Illnesses in a group are likely to be related to an identified, shared exposure (e.g. particular meal, event, or establishment), if group members have which of the following? • Ill persons all have the same symptoms. • Ill persons shared food or a meal prior to onset of illness and had no other common exposures. • Onset of the illness is consistent with the timing of the exposure. • All of the above

44. Quick Quiz • Which of the following can improve the accuracy of a food history solicited during a foodborne illness complaint? • Have case look at a calendar and identify key events to jog memory. • Have case review credit card or cash register receipts to identify where or what they ate. • Enlist help of dining partners. • All of the above

45. Quick Quiz • All of the following are true of pathogen-specific surveillance EXCEPT • Detects all types of foodborne illness. • Relies on reports from health-care providers and clinical laboratory staff. • Is the primary means to detect widespread outbreaks such as multistate outbreaks. • Has an inherent lag in reporting due to time necessary to confirm pathogen through laboratory testing.

46. Quick Quiz • All of the following are important roles for local health departments in national pathogen-specific surveillance EXCEPT • Collect information on local cases in a format consistent with other investigators. • Share case reports with state health department in a timely fashion. • Be alert to outbreaks in other jurisdictions. • Submit all patient isolates directly to CDC.