MODULE 2 – FOODBORNE DISEASE SURVEILLANCE AND OUTBREAK DETECTION FOODBORNE DISEASE OUTBREAK INVESTIGATION TEAM TRAINING

2 1.Describe the surveillance of foodborne illness through complaint systems. 2.List ways to improve the accuracy of a food history obtained in a foodborne illness complaint. 3.Describe the surveillance of foodborne illness through pathogen-specific surveillance. 4.Recognize a possible outbreak using a complaint system or pathogen-specific surveillance. 5.Describe the role of local public health in national pathogen-specific surveillance. AT THE END OF THIS MODULE, YOU WILL BE ABLE TO

3 Many ways to find out about cases of foodborne illnesses and outbreaks Two primary means  Foodborne illness complaint systems  Pathogen-specific surveillance (notifiable disease reporting) FOODBORNE DISEASE SURVEILLANCE

4 FOODBORNE ILLNESS COMPLAINT SYSTEMS

5  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 used to link cases together COMPLAINT SYSTEMS

6 STEPS IN RECEIVING COMPLAINTS Illness in individual or group Interview of complainant Documentation of information Key information entered into log Complaint to local health department Evaluation of reports over time for outbreaks Routine review of log Evaluation of individual reports for immediate action Starts with complaint by consumer Common exposures link cases over time 

7 INTERVIEW OF COMPLAINANT Who is affected? What is the problem? When did problem occur? Where? Why/how? (name, age, and sex) (symptoms, diagnosis) (date/time of onset) (travel, water, contact with ill persons or animals, suspect food or meal, food history) (place of residence and exposure) 

8 Complete food history including  Foods eaten in 5 days before onset of illness − If norovirus likely, focus on 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 COLLECTING FOOD HISTORIES

9 Divide into groups of three. One person will be the interviewer; one, the complainant; and one, an evaluator. 1.The interviewer should solicit a 5-day food history from the complainant. 2.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. 3.Was it easy or difficult? Did you get a complete history? What approaches were helpful? SMALL GROUP EXERCISE Be prepared to share with class. Time: 10 minutes

10  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 IMPROVING FOOD HISTORIES Have complainant: 

11  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 ENTERING INFORMATION INTO LOG

12 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 EVALUATION OF COMPLAINTS

13 EXAMPLE LOG OF COMPLAINTS > Complaint Systems

14 Illnesses are likely to be related to an identified, shared exposure, 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 GROUP ILLNESSES DUE TO IDENTIFIED, SHARED EXPOSURE

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

16 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 EVALUATION OF COMPLAINTS (CONT’D)

17  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. RESPONSE TO COMPLAINTS

18 Rational approach to follow-up  As required by local law/statute or  If complainant observed 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 with shared foods FOLLOW-UP OF COMMERCIAL ESTABLISHMENTS

19 Study the foodborne illness log at the end of this module spanning a 2-week period and determine: 1.Is the number of complaints what you would expect for the period covered? 2.Are there individual complaints of concern? 3.Are there common exposures (e.g. foods, establishments) across complaints signaling an outbreak? SMALL GROUP EXERCISE Be prepared to share with class. Time: 10 minutes

20 Primary means to detect outbreaks that are  Localized (involving only one jurisdiction)  Due to diseases with a short incubation period STRENGTHS OF COMPLAINT SYSTEMS

21 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 COMPLAINT SYSTEM ISSUES

22 PATHOGEN-SPECIFIC SURVEILLANCE

23  Also called “reportable diseases,” “notifiable diseases,” or “laboratory-based reporting”  Reports of individual lab-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 SURVEILLANCE

24 STEPS IN PATHOGEN-SPECIFIC SURVEILLANCE Illness in individual Analysis of cases for clusters/outbreaks Individual seeks health care Specimen collected Diagnosis by health-care provider/laboratory Initial report to health department Submission of isolate to public health laboratory Follow-up interview of case Further characterization Entry into electronic database Forward to CDC Starts with positive lab result Common pathogen links cases over time 

25  From health-care provider or laboratory  Standardized form (often pathogen-specific)  Information of interest − Patient identifiers − Basic demographic information − Clinical information − Laboratory results INITIAL REPORT

26  To identify potential exposures leading to illness  Similar to interview for 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 FOLLOW-UP INTERVIEW OF CASE

27  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 LABORATORY CHARACTERIZATION OF PATHOGEN

28 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 ANALYSIS FOR CLUSTERS

29 ANALYSIS BY CAUSATIVE AGENT Month of Diagnosis Number of Case Lab-confirmed salmonellosis cases by month of diagnosis, 2010 All Salmonella

30 Lab-confirmed salmonellosis cases by month of diagnosis, 2010 ANALYSIS BY CAUSATIVE AGENT SUBTYPE Salmonella Javiana All Salmonella Month of Diagnosis Number of Case

31 ANALYSIS BY CAUSATIVE AGENT AND AGE GROUP Salmonella Javiana among persons <5 yrs. Lab-confirmed salmonellosis cases by month of diagnosis, 2010 Month of Diagnosis Number of Case All Salmonella Salmonella Javiana

32 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) STRENGTHS OF PATHOGEN-SPECIFIC SURVEILLANCE

33  Incomplete detection and reporting PATHOGEN-SPECIFIC SURVEILLANCE ISSUES  Population Person Becomes Ill Person Seeks Care Specimen Obtained Lab Tests for Organism Culture-confirmed Case Reported

34  Incomplete detection and reporting  Elapsed time PATHOGEN-SPECIFIC SURVEILLANCE ISSUES  Patient eats food Patient becomes ill Stool sample collected Salmonella identified Isolates received by public health lab Case confirmed as part of cluster Incubation period=1-3 d Time to contact with health care=1-5 d Shipping time=0-7 d Serotyping and PFGE=2-10 d Time to diagnosis=1-3 d Elapsed Time for Salmonella Reporting

35  Incomplete detection and reporting  Elapsed time  Availability of isolate for further characterization PATHOGEN-SPECIFIC SURVEILLANCE ISSUES

36 Complaint system Pathogen-specific surveillance Types of foodborne illnesses detected AllOnly selected diseases Initiating eventConsumer complaintPositive lab result Means to link casesCommon exposuresSame pathogen Linkage of cases across jurisdictions Not usually Yes Exclusion of unrelated cases DifficultGood SpeedFastRelatively slow Types of outbreaks best detected Localized outbreaks; short incubation illnesses Widespread; low-level contamination events; long incubation illnesses COMPARISON OF SURVEILLANCE SYSTEMS

37 NATIONAL PATHOGEN-SPECIFIC SURVEILLANCE SYSTEMS

38 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)  Lab network that uses standardized PFGE methods  PFGE patterns uploaded by labs for STEC, Salmonella, Shigella, Listeria, Campylobacter  Comparisons of patterns to identify clusters NATIONAL PATHOGEN-SPECIFIC SURVEILLANCE

39 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 PATHOGEN-SPECIFIC SURVEILLANCE

40 Local pathogen-specific case reports and lab 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 as quickly as possible.  Use national systems to learn about outbreaks in other jurisdictions. ROLE OF LOCAL HEALTH DEPARTMENTS 

41  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 concern about needle/ blade tenderized steaks WHAT DIFFERENCE DOES ONE LOCAL CASE MAKE?

42 QUICK QUIZ

43 QUICK QUIZ 1.Typically common exposures are used to detect outbreaks through a foodborne illness complaint systems whereas a common pathogen is used to detect outbreaks through pathogen-specific surveillance systems A.True B.False

44 QUICK QUIZ 2.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? A.Ill persons all have the same symptoms. B.Ill persons shared food or a meal prior to onset of illness and had no other common exposures. C.Onset of the illness is consistent with the timing of the exposure. D.All of the above

45 QUICK QUIZ 3.Which of the following can improve the accuracy of a food history solicited during a foodborne illness complaint? A.Have case look at a calendar and identify key events to jog memory. B.Have case review credit card or cash register receipts to identify where or what they ate. C.Enlist help of dining partners. D.All of the above

46 QUICK QUIZ 4.All of the following are true of pathogen-specific surveillance EXCEPT A.Detects all types of foodborne illness. B.Relies on reports from health-care providers and clinical laboratory staff. C.Is the primary means to detect widespread outbreaks such as multistate outbreaks. D.Has an inherent lag in reporting due to time necessary to confirm pathogen through laboratory testing.

47 QUICK QUIZ 5.All of the following are important roles for local health departments in national pathogen- specific surveillance EXCEPT A.Collect information on local cases in a format consistent with other investigators. B.Share case reports with state health department in a timely fashion. C.Be alert to outbreaks in other jurisdictions. D.Submit all patient isolates directly to CDC.