MDH Approach to Foodborne Disease Outbreak Investigations and other topics Josh Rounds MPH Epidemiologist, Foodborne Diseases Unit Minnesota Department of Health Office phone:

Why investigate outbreaks? –Prevent illness, stop transmission –Prevent future outbreaks Identify and change practices in food production that contributed to the outbreak Recognize new vehicles –Media interest provides opportunities for public health communication and can influence policy

Confirmed Foodborne Outbreaks, Minnesota, No. Outbreaks Year of Outbreak

Confirmed Foodborne Outbreaks by Etiology, Minnesota, (n=600) 59% 13% 5% 10 % Salmonella E. coli O157:H7 10% Bacterial intoxications 3% Scombroid Other/unknown

Centralized at State Health Department Coordinated by one person Complaints received from public directly or from public via local health departments

Assessing Foodborne Illness Complaints Number ill Other common exposures? Do incubation and symptoms fit together? Get complete food history – complainant may not be targeting correct exposure Enter complaints into a database –identify independent complaints naming same establishment –compare to reportable disease interviews

Moving from Complaint to Outbreak Investigation Multiple independent complaints Illnesses among meal companions with no other common exposures Clinical symptoms and median incubation used to suggest an etiology and inform the EH investigation

Selected Enteric Pathogens Reported to MDH, Year Number of Cases Campylobacter Salmonella E. coli O157:H7 Cryptosporidium Shigella

Reportable Bacterial Enteric Pathogen Surveillance in Minnesota Isolates (or clinical specimens) must be submitted to the Minnesota Department of Health (MDH) Real-time pulsed-field gel electrophoresis (PFGE) subtyping of all isolates by MDH Public Health Laboratory Routine, real-time interviews of all cases by MDH staff

Molten agarose Pulsed-Field Gel Electrophoresis (PFGE) Lysis Enzyme digestion (XbaI) Bacteria Pulse electrophoresis DNA 18 hours 1.5 hours

PulseNet Laboratory Network Local Databases PulseNet National Databases (CDC) Participating Labs PFGE Patterns

Number of Cases August SeptemberOctober 8 Week of Specimen Collection All Salmonella Enteritidis Isolates Received August-October 2011 (n=63)

Number of Cases August SeptemberOctober 8 All Salmonella Enteritidis SE1B173 Isolates Received August-October 2011 (n=7) Week of Specimen Collection

Exposure Assessment Difficult for cases to recall specific food exposures that likely occurred several weeks ago –Use shopper cards or credit card receipts Interview all cases, ASAP Collect details on specific exposures –Restaurant, grocery store names –Brand, variety names –Open-ended food histories

Symptom and Exposure Questions - Drinking water- Animal contact - Raw milk- Daycare - Travel- Ill contacts - Gatherings- Recreational water

Food or Beverages Outside the Home

Minnesota Approach to Investigation of PFGE Clusters: Dynamic Cluster Investigation Model Case #1 Case #4 Case #3 Case #2

Response for PFGE Clusters Minimum: Compare case interviews Maximum: Case-control study Food Testing Product tracing as part of epidemiologic investigation

Food Tracebacks Traditionally done after a food vehicle is implicated by other means (epi, lab testing) Increasingly necessary as part of epidemiologic investigation to implicate a food item –Especially for generic or co-linear foods –Can do quickly, if not for regulatory purposes –Another way to increase specificity of exposure Requires strong working relationship between Epi-EH-Agriculture to be effective

Keys to MDH Success in Foodborne Outbreak Investigations Mandatory isolate submission to MDH Real-time PFGE subtyping of all isolates Daily communication between lab and epi Centralized surveillance/investigation of cases –Done at state; counties not involved Real-time interviews done with all cases using a detailed questionnaire

Keys to MDH Success in Foodborne Outbreak Investigations Investigate all clusters; follow leads aggressively Resources (people) dedicated to enteric diseases –Experience from working with clusters every day leads to knowledge of when to push, how hard to push with each cluster Sense of urgency

Multi-state Salmonella I 4,[5],12:i:- Outbreak Associated with Pot Pies, cases 41 states 32% hospitalized

Date of onset, 2007* Number *Date of illness onset reported for 336 cases and estimated for 65 cases June 26 Routine state investigations August 14 Standard questionnaire September 4 Open-ended interviews September 19 Focused questionnaire Unrefined chicken and egg hypotheses Hypothesis Generation

Dynamic Cluster Investigation - Pot Pies Consumed Brand X PP 4 10/4 afternoon “trawling” questionaire 1 Initial trawling questionnaire interview date 9/10 2 9/ /3 night Re-interviewed cases about frozen foods and pot pies 10/4 morning 10/4 evening PP Exposure added

Presentations of Outbreaks due to Commercially Distributed Food Items Cases in community, no obvious common exposure –Retail food (grocery stores) Cases occur among patrons of restaurant(s) Cases clustered in institution(s) Any combination of above three For every type of outbreak, the key to solving it is to get detailed exposure information for as many cases as possible, as soon as possible!!!

MPH Students from U of MN SPH Hired as temporary MDH employees ~20 hours/week, including evenings and weekends Intensive training, oversight by MDH epidemiologists Person-power to rapidly interview all cases, do calls for cluster investigations “Team Diarrhea”

Number of Laboratory-Confirmed Cases of Salmonella Saintpaul, by Date of Illness Onset – United States, 2008 * MMWR 2008 Vol. 57 No. 34

Salmonella Saintpaul Patron Cases Associated with Restaurant A by Date of Isolate Receipt in MDH Laboratory, June 2008 June Date of Isolate Receipt Number of Cases Two cases name Restaurant A

Restaurant A Outbreak June 30, 2008 MDH and Ramsey County staff visited restaurant –Interviewed management and employees –Collected invoices for ingredients used in dishes consumed by cases –Requested credit card receipts from same time period –Obtained copies of menu

Univariate and Multivariate Results of Minnesota Case-Control study Ingredient No. cases exposed/total ORpaOR p Red salsa13/1814.7<0.001Not significant Avocado salsa14/197.5<0.001Not significant Mexican garnish 17/1969< Red peppers17/1943<0.001Not significant Cilantro18/1921.4<0.001Not significant Fresh tomatoes 6/ Not significant Jalapenos17/1969< <0.001

Multistate Outbreak of E. coli O157:H7 Infections: 1 st 6 cases Median age, 63 years 83% male –15-year-old male –55-year-old male –62-year-old male –64-year-old male –70-year-old female –78-year-old male

All 6 reported consuming in-shell mixed nut or in shell hazelnut (filbert) –Hazelnuts were included in mixed nuts –2 reported only in-shell hazelnuts (not other in-shell nuts) 5 of 6 purchased from bulk bins Investigation of 1 st 6 Cases

Case/Retail Distributor A Distributor B

Recall of in-shell hazelnuts shipped by California distributor from November 2 through December 22 –Hazelnuts originated in Oregon, but poor record keeping prevented identification of grower Public advisories Interventions

March 5: Hazelnuts from Minnesota case home March 25: Mixed nuts returned to distributor in Wisconsin March 28: Mixed nuts from distributor in California Isolation of Outbreak Strain of E. coli O157:H7 from Hazelnuts/Mixed Nuts

Cronobacter sakazakii Gram-negative rod-shaped bacterium in the family Enterobacteriaceae Common in the environment Rarely can cause sepsis, meningitis, or necrotizing enterocolitis Infants (particularly premature infants) are at highest risk for severe disease

Cronobacter sakazakii Outbreaks associated with powdered infant formula Powdered infant formulas are not commercially sterile products Formula can also be contaminated when preparing formula Temperature abuse

Traveled Hawaii’s Puna district to learn about organic farming Hospitalized for over a month lost 50 pounds Rat Lungworm

Parasitic nematode Most cases in Southeast Asia and the Pacific Basin –Also found in Australia, some areas of Africa, the Caribbean, Hawaii and Louisiana Bacterial meningitis; nausea, vomiting, neck stiffness, and severe headaches Most infections resolve after 2-8 weeks Rarely can lead to neurologic dysfunction or death

Rat Lungworm (Angiostrongylus cantonensis)

Rat Lungworm Risk factors: –Eating raw or undercooked snails or slugs –Eating pieces of snails and slugs accidentally chopped up in vegetables, vegetable juices, or salads

Globalization –Global movement of diseases in people and on food –Salmonella sushi outbreak Local doesn’t automatically mean it is safe –Media reports & consumers only hear about big nationwide outbreaks –Smaller producer = smaller outbreak Improve communication of outbreak investigation findings to industry –Prevent future outbreaks –More timely than guidance documents

Questions