Investigating Foodborne Disease Outbreaks: The CDC Perspective

1. Investigating Foodborne Disease Outbreaks: The CDC Perspective

2. Old focal scenario Large number of cases in one jurisdiction Detected by affected group Local investigation Local food handling error Local solution

3. Public Health Infrastructure in the United States

4. Federal Roles CDC: Disease surveillance Outbreak detection and investigation Education and training of public health staff FDA & FSIS: Food safety policies Inspection and enforcement Product recall and traceback Investigation of farm and production facilities

5. Foodborne Disease Outbreak Investigations Goals of investigations Immediate control of outbreak and prevention of illnesses Provide opportunities to identify gaps in food safety systems Outbreak epidemiology changing Globalization, centralization, industrialization Number of possible outbreaks detected has grown substantially Effective investigations key to reducing burden of foodborne disease Identify food vehicles and factors which lead to outbreaks

7. Cycle of Foodborne Outbreak Control & Prevention: Stages of an Investigation The first stage of an outbreak investigation falls under surveillance. First, a cluster of infections is detected through surveillance. A cluster is an increase in infections above baseline for a given time period. The first stage of an outbreak investigation falls under surveillance. First, a cluster of infections is detected through surveillance. A cluster is an increase in infections above baseline for a given time period.

8. National Surveillance for Bacterial Foodborne Infections Reports to CDC of suspected outbreaks by state and local health departments Laboratory-based surveillance of clinical isolates Serotype results PulseNet National surveillance for bacterial foodborne infections can occur in several ways. These include Reports to CDC of suspected outbreaks by state and local health departments, and laboratory-based surveillance of clinical isolates, through Serotype results And reports from PulseNet�.. National surveillance for bacterial foodborne infections can occur in several ways. These include Reports to CDC of suspected outbreaks by state and local health departments, and laboratory-based surveillance of clinical isolates, through Serotype results And reports from PulseNet�..

9. What is PulseNet USA? National network of >75 public health and regulatory laboratories Perform molecular typing of foodborne disease-causing bacteria Current method is pulsed-field gel electrophoresis (PFGE) Create DNA �fingerprints� Share DNA �fingerprints� electronically DNA �fingerprints� are kept in dynamic database at CDC available on-demand to participants

10. PulseNet Data Analysis: Searching for Clusters Patterns obtained by PFGE are electronically submitted to the PulseNet national PFGE pattern database at CDC via the internet For Cluster Detection 60-day cluster searches are performed for all organisms with the exception of Listeria. 120-day searches are used for Listeria because of its longer incubation time. We visually compare the patterns using tools within the BioNumerics software and report any matches to foodborne epidemiologists.Patterns obtained by PFGE are electronically submitted to the PulseNet national PFGE pattern database at CDC via the internet For Cluster Detection 60-day cluster searches are performed for all organisms with the exception of Listeria. 120-day searches are used for Listeria because of its longer incubation time. We visually compare the patterns using tools within the BioNumerics software and report any matches to foodborne epidemiologists.

11. Cycle of Foodborne Outbreak Control & Prevention During this presentation, we will use the Salmonella Typhimurium outbreak as an example to illustrate how foodborne outbreaks are investigated. We will refer back to this cycle throughout the presentation. During this presentation, we will use the Salmonella Typhimurium outbreak as an example to illustrate how foodborne outbreaks are investigated. We will refer back to this cycle throughout the presentation.

12. CDC�s OutbreakNet Team Supports a national network of epidemiologists and other public health officials who investigate outbreaks of foodborne, waterborne, and other enteric illnesses in the United States Collaboration between CDC and U.S. State and local health departments U.S. Department of Agriculture (USDA) U.S. Food and Drug Administration (FDA) Works in close partnership with PulseNet The national molecular subtyping network for foodborne disease surveillance Helps ensure Rapid, coordinated detection & response to multi-state enteric disease outbreaks Promotes comprehensive outbreak surveillance

15. Hypothesis-Generating Tracebacks Data on product distribution production can be critical in development of hypothesis Evaluate potential sources Ways to obtain this information State Departments of Agriculture Regulatory agencies Involvement before a product has been implicated can pose unique problem for some agencies

18. Prevention Measures Epidemiologic Investigations The epidemiologic investigation just described led to a number of tracebacks and environmental inspections. Traceback of tomatoes did not converge to a single location, (click) however tracebacks of jalapeno peppers led to an agricultural firm in McAllen, Texas. Testing at this facilty identified a sample of jalapenos peppers with the outbreak strain of Salmonella Saintpaul. Further traceback of jalapeno peppers from this agricultural firm in McAllen, Texas led to a packing facility in Neuvo Leone, Mexico. (click) This packing facility received shipments of jalapeno peppers from a number of growers. The positive jalapeno peppers sample identified at agricultural firm in McAllen, Texas was likely grown at farm A. (click) This farm grows jalapeno and serrano peppers as well as tomatoes which were all being harvested during the time period of the outbreak. An investigation of another farm (Farm B) (click) that provided jalapeno peppers to the packing facility in Neuvo Leone, Mexico identified a sample of serrano peppers and a water sample with the outbreakstrain of Salmonella Saintpaul. This farm grows jalapeno and serrano peppers.The epidemiologic investigation just described led to a number of tracebacks and environmental inspections. Traceback of tomatoes did not converge to a single location, (click) however tracebacks of jalapeno peppers led to an agricultural firm in McAllen, Texas. Testing at this facilty identified a sample of jalapenos peppers with the outbreak strain of Salmonella Saintpaul. Further traceback of jalapeno peppers from this agricultural firm in McAllen, Texas led to a packing facility in Neuvo Leone, Mexico. (click) This packing facility received shipments of jalapeno peppers from a number of growers. The positive jalapeno peppers sample identified at agricultural firm in McAllen, Texas was likely grown at farm A. (click) This farm grows jalapeno and serrano peppers as well as tomatoes which were all being harvested during the time period of the outbreak. An investigation of another farm (Farm B) (click) that provided jalapeno peppers to the packing facility in Neuvo Leone, Mexico identified a sample of serrano peppers and a water sample with the outbreakstrain of Salmonella Saintpaul. This farm grows jalapeno and serrano peppers.