Outbreak Investigations of Foodborne Illness Sherri A. McGarry U.S. Food and Drug Administration Center for Food Safety & Applied Nutrition Office of Food Defense, Communication & Emergency Response

FDA & USDA: Which agency regulates these products? Vegetables Seafood Chicken Dietary supplements Infant formula Frozen pizza with extra pepperoni USDA FDA √ √ √ √ √ √ FDA regulates foods (except meat, poultry, and some egg products), food and color additives, cosmetics, dietary supplements, infant formula

Outbreaks– FDA regulated products 1996 – 2008: Dairy 21 Eggs207 Proc Foods 37 Produce 77 Seafood114 Sprouts 27

Illnesses – FDA regulated foods : Dairy 349 Eggs 6609 Proc Foods 3684 Produce>9000 Seafood 2819 Sprouts 1633

Fresh Produce Outbreaks TomatoesSalmonella Leafy GreensE. coli O157 CantaloupeSalmonella Hot peppersSalmonella Herbs Cyclospora, E. coli O157, Shigella RaspberriesCyclospora Green OnionsHepatitis A MangoSalmonella

FDA’s Role in Outbreak Investigations Investigation and coordination in multi-state outbreaks Review epidemiological, laboratory, and environmental data Tracebacks of implicated foods Farm investigations Removal of implicated products from commerce Alert consumers Lab assistance Evaluate data to identify trends and develop policy, guidance, and/or regulations to prevent future outbreaks Requires teamwork!

Teamwork among scientists Types of scientists needed: Microbiologists Laboratory scientists Epidemiologists Environmental sanitarians Veterinarians Food technologists Toxicologists Others – physicians, biologists, agriculturists, etc.

Anatomy of an Outbreak investigation Disease Surveillance Epidemiological investigation Laboratory Analysis Environmental investigation Traceback / traceforward Farm / Processor investigation

1. Disease Surveillance Why do we conduct surveillance of disease and investigate outbreaks? Identify illnesses and potential outbreaks Prevent additional illnesses Identify causes to prevent future illnesses and outbreaks Who is involved in surveillance? Federal agencies – CDC, FDA, USDA, EPA Laboratories Local and state public health departments Science at work → Epidemiologists, Physicians, P ublic Health Officials, Veterinarians, Lab scientists

Surveillance and Reporting Illness exposures in the general population Person becomes ill Person seeks medical care/reports illness to HD Specimen obtained Lab tests for pathogen Culture confirmed case Illness reported to HD and CDC

How are multi-state foodborne outbreaks recognized? Electronic Foodborne Outbreak Reporting System (eFORS) Database of reports of foodborne disease outbreaks submitted through the internet by local or state health departments PulseNet Database of molecular subtyping (or “fingerprinting”) of bacteria by pulsed-field gel electrophoresis (PFGE) submitted by a national network of laboratories

Why does it take so long?

2. Epidemiological investigation State and local public health officials – collect case information and evaluating data Determine epidemiologic associations Case interview information Attack rates of illness by food type Test hypothesis → case control study Interpreting statistical significance Implicate the food causing illness

3. Laboratory Analysis Lab testing Clinical samples Food samples Environmental samples Match clinical results to food product and/or environmental results Science at work → Microbiologists, Chemists, Toxicologists, Lab scientists

Detecting outbreaks Lab tools Standard methods to detect pathogens National database and historical patterns PFGE PHLIS – Public Health Laboratory Information System  Electronic reporting system for Salmonella and Shigella human isolates  statistical algorithm designed to detect unusual clusters of isolates of Salmonella infection

Detecting outbreaks - Lab Lab associations Clustering in time of cases Same genus and species Same DNA fingerprint Between cases and between cases and food Unusual spikes in illness

4. Environmental investigation Best case scenario: The epidemiologic investigation helps guide the environmental investigation including areas to focus collection and testing of environmental/product samples However…. Product samples may no longer be available Changes likely have occurred in environment Science at work → Environmental Sanitarians, Epidemiologists, Food technologists, Microbiologists

Environmental investigation State and local response: –Food preparation review –Interview food workers –Determine if time, temperature abuse or cross-contamination occurred –Collect samples –Collect records Federal response: –Traceback (records) –Source investigations along the distribution chain Determine if contamination occurred at that point Collect samples Identify common source

5. Traceback Epi and/or lab evidence implicates a food Track food item back through the distribution chain to a common source Investigate

6. Farm investigation Zoonotic Salmonella E. coli O157:H7 Campylobacter Human Shigella Hepatitis A virus Norovirus Cyclospora Know your pathogen!

Sources of Contamination Multiple modes: Soil Water Workers Animals Science at work → Water Specialists, Agriculturists, Wildlife Experts, Microbiologists Everything is connected!

FARM INVESTIGATIONS

Potential Sources of Contamination: Ponds Worker HygieneEquipment Animals

Reality Check Seldom do we find the “smoking gun” Why not? A. Delay between when the outbreak was detected and when consumers ate the contaminated food B. Conditions at the source are not the same as when contamination occurred C. Finding the pathogen is difficult D. All of the above

Case Study…

Be the Detective! Contamination at the Farm: Salmonella Saintpaul Spring/Summer 2008

Early Sequence of Events Late May - CDC gave FDA an early alert of Salmonella Saintpaul illnesses in NM & TX tomatoes a likely vehicle CDC notifies FDA that tomatoes implicated FDA initiates traceback investigation June 3 – Consumer advisory for NM & TX – raw red round and roma/plum tomatoes

What to Trace? Select geographically diverse to triangulate Prefer cluster vs sporadic case traceback No clusters so select cases with the best: Exposure info, receipts to document dates, good food historians, etc FDA and CDC collaborate to identify best cases to trace

Traceability Challenges Lack of rapid connectivity Lack of unique identifier Repacking Co-mingling Addresses, ship and reciept dates Packaging (ie. cases) gone Produce no longer available Producing states importing as well

Sequence of Events - distribution Intelligence gathering: Early outreach to industry on distribution patterns Industry provides general harvest info USDA, academic, FDA imports data Epi suggests consumers nationwide at risk Early traceback info support June 7 - Consumer advisory expanded from NM and TX to nationwide not to eat raw red round and roma/plum tomatoes

Findings… Tomatoes shipped from FL to Idaho Transportation costs may not be as much of a factor as originally thought Transition time for harvest Key production areas - FL and MX Tomatoes in high demand, quick turnaround, unusual market and distribution patterns

Responding to an Evolving Picture No single common convergence on tomato traceback – Florida and Mexico Several firms appear more than once Are the problems with traceability making it impossible to find the convergence? Indications, but no statistical association of other ingredients causing illness Comparing ingredients of suspect menu items among clusters Tough to trace guacamole and salsa

Stepped Up FDA Actions Tomato farm investigations – FL & MX Increased border sampling of multiple produce items Cilantro, tomatoes, peppers, basil Sampling assignment covering all points in the chain Activation of FERN, state assistance for testing

Is it tomatoes? More than on vehicle? MN finds statistical association with jalapeno pepper FDA initiates pepper & Serrano tracebacks FDA & CDC face-to-face collaboration at Emergency Operations Centers FDA outreach to industry for pepper harvest info, geographic, distribution info, production and packing practices

FDA Pepper Product Investigations Initiate hot pepper traceback Initial traceback lead only to Mexico FDA investigation team sent to MX

More pieces of the puzzle Investigations find issues at multiple points in distribution chain in MX June 21 - Positive jalapeno sample of outbreak strain collected at distribution center in McAllen, TX

IMPORT ALERT #99-23, "DETENTION WITHOUT PHYSICAL EXAMINATION OF RAW FRESH FRUITS AND VEGETABLES FROM LISTED MANUFACTURERS, SHIPPERS, AND/OR GROWERS DUE TO THE PRESENCE OF PATHOGENIC CONTAMINATION", ATTACHMENT - 7/30/08 Posted on FDA’s website FDA IMPORT ALERTS Due to the presence of Salmonella

Some Figures… 447 Investigations by FDA and State Partners 244 Firms visited for traceback investigations Over 30 FDA field assignments Samples – Product and environmental Distributors, repackers, packing, farms FDA teams in MX: 11 investigations

FDA: 482 total samples (sample = multiple subs not one) 34 Salmonella positive 3 Salmonella Saintpaul matches FERN: 199 total samples 13 Salmonella positive 1 Salmonella Saintpaul not match SAMPLE RESULTS AS OF 8/5/08

Stayed tuned for Peppers...

Lessons Learned Lessons learned in all areas: Communication Response Investigations epi Intactions among state and feds Value of increased environmental sampling Implemented in recent outbreaks

Conclusions Science plays a major role in detecting outbreaks and investigating the source of contamination in foodborne outbreaks Understanding how contamination occurred is critical in developing measures to minimize ongoing outbreaks and prevent future ones Consumers, government, academia, and industry all play a vital role in protecting public health

Resources Bad bug book, food safety, press releases on outbreaks, education, and more PulseNet, surveillance, pathogens, education, and more