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

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Presentation on theme: "1Surveillance and outbreak detection Foodborne Disease Outbreak Investigation Team Training: Module 2 – Foodborne Disease Surveillance and Outbreak Detection."— Presentation transcript:

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

2 2Surveillance and outbreak detection Module Learning Objectives At the end of this module, you will be able to 1.Describe the surveillance of foodborne illness through notification/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 notification/complaint system or pathogen- specific surveillance. 5.Describe the role of local public health in national pathogen-specific surveillance.

3 3Surveillance and outbreak detection 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 4Surveillance and outbreak detection Foodborne Illness Notification/Complaint Systems

5 5Surveillance and outbreak detection 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 6Surveillance and outbreak detection 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 > Notifications/complaints Starts with complaint by consumer Common exposures link cases over time 

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

8 8Surveillance and outbreak detection Collecting Food Histories Complete food history important including –Foods eaten in 5 days before onset of illness  If illness suggestive of norovirus, 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 > Notifications/complaints

9 9Surveillance and outbreak detection Small Group Exercise Divide into groups of two. One person will be the interviewer; one will be the complainant. 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 food history? What approaches were helpful? Time: 10 minutes Be prepared to share your experience with the class.

10 10Surveillance and outbreak detection Improving Food Histories 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 Have complainant > Notifications/complaints

11 11Surveillance and outbreak detection 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 12Surveillance and outbreak detection 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 13Surveillance and outbreak detection 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 14Surveillance and outbreak detection 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. 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. > Notifications/complaints Due to Exposure

15 15Surveillance and outbreak detection 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 16Surveillance and outbreak detection 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 17Surveillance and outbreak detection 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 18Surveillance and outbreak detection Group Exercise 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? Divide into groups by table. Study the foodborne illness log at the end of this module spanning a 2- week period and determine: Time: 10 minutes Be prepared to share your thoughts with the class.

19 19Surveillance and outbreak detection 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 20Surveillance and outbreak detection 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 21Surveillance and outbreak detection Pathogen-specific Surveillance

22 22Surveillance and outbreak detection 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 23Surveillance and outbreak detection 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 > Pathogen-specific Starts with positive lab result Common pathogen links cases over time 

24 24Surveillance and outbreak detection 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 > Pathogen-specific Example in appendix

25 25Surveillance and outbreak detection 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 26Surveillance and outbreak detection 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 27Surveillance and outbreak detection 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 28Surveillance and outbreak detection Analysis by Causative Agent Month of Diagnosis Number of Case Lab-confirmed salmonellosis cases by month of diagnosis, All Salmonella > Pathogen-specific

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

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

31 31Surveillance and outbreak detection 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 32Surveillance and outbreak detection Pathogen-specific Surveillance Issues Incomplete detection and reporting  Population Person Becomes Ill Person Seeks Care Specimen Obtained Lab Tests for Organism Culture-confirmed Case Reported > Pathogen-specific

33 33Surveillance and outbreak detection Pathogen-specific Surveillance Issues Elapsed time  Incomplete detection and reporting 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 > Pathogen-specific

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

35 35Surveillance and outbreak detection Comparison of Surveillance Systems Notification/ 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 usuallyYes 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

36 36Surveillance and outbreak detection National Pathogen-Specific Surveillance Systems

37 37Surveillance and outbreak detection 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 Pathogen-specific Surveillance > National surveillance

38 38Surveillance and outbreak detection 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 39Surveillance and outbreak detection 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 40Surveillance and outbreak detection 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 41Surveillance and outbreak detection Quick Quiz

42 42Surveillance and outbreak detection Quick Quiz 1.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 A.True B.False

43 43Surveillance and outbreak detection 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

44 44Surveillance and outbreak detection 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

45 45Surveillance and outbreak detection 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.

46 46Surveillance and outbreak detection 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.


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