Changing Landscape of Foodborne DiseaseArthur P. Liang, M.D., M. P. H.

Senior Advisor for Food Safety

Division of Foodborne Waterborne & Environmental Diseases

Centers for Disease Control & Prevention

CDC & States: The vital link

CDC provides the vital

link between illness in

people & the food safety

systems of government

agencies & food

producers.

Disclosures

• Findings & conclusions in this presentation are

those of the author and do not necessarily

represent the views of the Centers for Disease

Control & Prevention

• Thank you to HPP for invitation

• Speaker reserves the right to say something

stupid, wrong or incredibly obvious

Executive Summary

• Genomics & Information Technology:

Accelerating pace of change

• Disease & Food surveillance finding a needle in a

haystack

• Food safety bar is being raised for ALL

More Class 1 Recalls(?)

Listeria Outbreaks & Incidence, 1983-2013

No. outbreaks

Incidence

(per million pop)

Era

Outbreaks per year

Median cases per

outbreak

Pre-PulseNet

0.3

69

Early

PulseNet

2.3

11

Listeria Initiative

2.9

5.5

Listeria Outbreaks & Incidence, 1983-2014

No. outbreaks

Incidence

(per million pop)

Era

Outbreaks per year

Median cases per

outbreak

Pre-PulseNet

0.3

69

Early

PulseNet

2.3

11

Listeria Initiative

2.9

5.5

WGS

8

4.5

Listeriosis Outbreaks & Incidence*, 1983-2015

No. outbreaks Incidence (per million pop)

WGS7.54

*2015 incidence rate preliminary data from FoodNet

The bacteria and viruses that cause the most illnesses,

hospitalizations, and deaths in the United States are:

• Salmonella

• Norovirus (Norwalk Virus)

• Campylobacter

• E. Coli

• Listeria

• Clostridium perfringens

https://www.foodsafety.gov/poisoning/causes/bacteriaviruses/

Accelerating pace of change…

• 1854 Era of Classical Epidemiology &

Microbiology 1920’s serotyping, 1940’s phage

typing

• 1998 PulseNet Era

• 2014 Genome Sequencing Era

John Snow (1813-1858)

Era of Classical Epidemiology & Microbiology

How do we know it’s food? Outbreak investigation

“church picnic” or “sore thumb”

• Large number of cases in one jurisdiction

− Detected by affected group

− Local investigation

− Local food handling error (s)

− Local solution

Outbreak Detected by patients / their doctor

On January 12

A pediatric gastroenterologist notified the

Washington State Dept of Health (WA DoH) of

increase in emergency dept visits for bloody

diarrhea & the hospitalization of 3 children

with hemolytic uremic syndrome.

January 15

No single exposure source from initial interviews

Emergency Room & lab alerted for case finding

January 18

• 37 cases identified. 27 ate at same fast food chain A

• Cases named 13 different store locations of restaurant chain A

Chain has 66 restaurants in the Washington State.

All received the same hamburger from the same distribution warehouse.

“Controls” = No diarrhea in 2 wks, friend of a case, matched by

neighborhood & age

Compare exposures of ill & well persons

Relative Risk = 1 No Association

Relative Risk < 1 Negative Association

Relative Risk > 1 Positive Association

Case - Control StudyCalculate Relative Risk or Odds Ratio

Ate Chain A

hamburger

Did not eat

hamburgerTotal

Sick 27 (73%) 10 37

Well 0 (0%) 16 16

matched odds ratio (mOR) = undefined; 95% confidence limit = 3.5 to ∞

“Local” food handling error:Cooking Temperatures for hamburger

1992 FDA – 140o F (60o C)

Washington State 155o F (68o C)

Cooking temperatures at implicated restaurants±60o C, probably less

50 gm frozen hamburger patties, cooked 1 minute on each size, regardless of whether meat was still red or not

WA DoH Advisory:

Outbreak likely linked to

Restaurant Chain A

hamburgers

“Local” Intervention

January 18

January 18, 1993: Voluntary Recall

Restaurant Chain A Press Release: “…measures to

ensure menu items prepared in accordance

with an advisory issued by the WA DoH.”

Recall: ~250,000 hamburger patties

2 3 4

E. Coli 0157 outbreak linked to fast-food chain hamburgers,

Pacific Northwest 1993 *

0

20

30

40

50

60

70

80

10

1 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

# o

f cases

January

US & primary culture-confirmed cases = 333

first

report

Improved

cooking temps

Public

alert

*cases by date of exposure who ate

Chain A hamburger on a single day

Cases of E. coli

by Date of Illness Onset

October 5-18, 1999

N=11

Compare exposures of ill & well persons

Case - Control Study

Calculate Relative Risk or Odds Ratio

Apple

cider

No apple

ciderTotal

Sick 10 (73%) 1 11

Well 0 (0%) 24 24

matched odds ratio (mOR) = undefined; unmatched

P-value < 0.00001)

Relative Risk > 1 Positive Association

“Local” Intervention

October 12, 1999

• OSDH ordered Orchard A to

• discontinue unpasteurized apple cider production

• recalled the apple cider

Environmental Results

Inspection of orchard & juice production site:

no violations found

− No dropped apples

− Washed & brushed apples

− Preservative added

− Warning labels

PulseNet Era: circa 1996 - present

In 1995, the Hubble Space Telescope found distant galaxies and star clusters never seen before.

Pulsed-field gel electrophoresis (PFGE) makes “invisible” outbreaks visible

PulseNet, since 1996

• DNA “fingerprints” shared electronically

• Kept in national database at CDC

PulseNet Era: circa 1996 - present

• Small numbers of cases in many jurisdictions

• Detected by lab-based subtype surveillance

• Multistate / Country Multi-disciplinary investigation

• More challenging to investigate

• Higher stakes?

• Identifying “new” foods/ingredients

March 2PulseNet identifies additional 7

cases in 6 states with an

indistinguishable PFGE pattern

Outbreak Detection by Lab

March 1NY State notified CDC of 4 cases

Salmonella with

indistinguishable PFGE patterns

Multi-state / National investigation

March 2

• Hypothesis generating questionnaire deployed

March 2

• First multi-state conference call

• Common exposures in early interviews:

• Chicken

• Seafood

• Fresh produce

• Japanese restaurant

• FDA notified & joins call

Outbreak Detection/Hypothesis Generation

March 1Cluster Identified

March 8

Exposure information points to seafood,

specifically sushi

7/8 report seafood, 5/8 report sushi

March 2

Investigation Initiated

Restaurant-exposure Clusters

March 22

4th cluster of unrelated ill persons at sushi same

restaurant in CT

March 16

3rd cluster of unrelated ill persons ate sushi from

same grocery store in WI

March 22

5th cluster of unrelated ill persons ate sushi same

restaurant in MD

March 8

2 unrelated ill persons in TX ate the same Japanese restaurant

March 13

Second cluster of unrelated ill persons at same Japanese restaurant in WI

= restaurant cluster

Case-Meals Other Customers

“Spicy Tuna” 84% 37% (range:29 - 53%)

Epi Analysis of meal receipts

March 29-April 9

• Compare ill patrons to well patrons from the several restaurants with

illness clusters

Well Patron Groups

Orders from diners who ate at one of the cluster restaurants

Orders placed during the same meal (lunch or dinner)

Close to the date when the ill person ate at the restaurant

FDA Traceback

Seafood

Importer/Supplier A

April 11

Seafood Processor A.

April 13-14

FDA issued two Import Alerts for fresh & frozen tuna from Seafood Processor A.

Seafood Importer/Supplier A recalls raw yellowfin tuna scrape

Three major pillars1) Epidemiology – interviews & loyalty cards, case-control, observed vs

expectedData from interviews of ill persons, distribution of cases in person/place/time,

results of analytic epidemiologic studies, the history of pathogen & past

outbreaks

2) Traceback – lot codes, industry consultationof a suspected vehicle linked with ill persons to identify a common point where

contamination may have occurred & an assessment of the production facility at

that common point

3) Laboratory – clinical, “DNA fingerprint,” food, environmental,

results from testing of a cases, suspected vehicle or the production

facility where contamination may have occurred

Higher epidemiologic “standard of proof”Multi-disciplinary Evidence to implicate food

Multistate Outbreak of S Bareilly & S Nchanga Infections

Associated with a Raw Scraped Ground Tuna Product,

2012

PulseNet increased the number of multistate

foodborne outbreaks reported to CDC: 1973-2010

PulseNet begins

10 new food vehicles identified in multistate outbreaks,

2006 - 2009

1. Bagged spinach, 2006

2. Carrot juice, 2006

3. Peanut butter, 2007 & 2009

4. Broccoli powder on a snack food, 2007

5. Pot pies, 2007

6. Canned chili sauce, 2007

7. Jalapeño & Serrano peppers, 2008

8. White pepper, 2009

9. Raw cookie dough, 2009

10. Black & red pepper, 2009-10

National Foodborne Outbreak Surveillance System

13 new food vehicles identified in multistate outbreaks,

2006 - 2011

1. Bagged spinach

2. Carrot juice

3. Peanut butter

4. Broccoli powder on a snack food

5. Dog food

6. Pot pies

7. Canned chili sauce

8. Hot peppers

9. White pepper

10. Raw cookie dough

11. Whole, raw papaya

12. Hazelnuts

13. Pine nuts

National Foodborne Outbreak Surveillance System

15 new food vehicles identified in multistate outbreaks,

2006 - 2012

1. Bagged spinach2. Carrot juice3. Peanut butter4. Broccoli powder on a snack food5. Dog Food6. Pot pies/frozen meals7. Canned chili sauce8. Hot peppers9. Pepper10. Raw cookie dough11. Hazelnuts12. Whole fresh papayas13. Pine nuts14. Kosher broiled chicken livers15. Scraped tuna product

National Foodborne Outbreak Surveillance System

29 new vehicles identified in multistate outbreaks 2006 -

2015

National Foodborne Outbreak Surveillance System

1. Bagged spinach

2. Carrot juice

3. Peanut butter

4. Broccoli powder on a snack food

5. Dog food

6. Pot pies/frozen meals

7. Canned hot dog chili sauce

8. Fresh hot chili peppers

9. Black pepper

10. Tahini sesame paste

11. Raw cookie dough

12. Aquatic water frogs

13. Fresh papaya

14. Frozen mamay fruit pulp

15. Bologna

16. In-shell hazelnuts

17. Pine nuts18. Par-cooked, broiled chicken livers

19. Scraped tuna

20. Cashew cheese

21. Bearded dragons

22. Sugar cane juice

23. Sprouted chia seeds

24. Almond butter

25. Caramel apples

26. Sprouted nut butters

27. Dried mushrooms (in truffle oil puree)

28. Crested geckos

29. Wheat flour

32 new vehicles identified in multistate outbreaks since

2006 – May 2017

1. Bagged spinach

2. Carrot juice

3. Peanut butter

4. Broccoli powder on snack food

5. Dog food

6. Pot pies/frozen meals

7. Canned hot dog chili sauce

8. Fresh hot chili peppers

9. Black pepper

10. Tahini sesame paste

11. Raw cookie dough

12. Aquatic water frogs

13. Fresh papaya

14. Frozen mamay fruit pulp

15. Bologna

16. In-shell hazelnuts

17. Pine nuts

18. Par-cooked, broiled chicken livers

19. Scraped tuna

20. Cashew cheese

21. Bearded dragons

22. Sugar cane juice

23. Sprouted chia seeds

24. Almond butter

25. Caramel apples

26. Sprouted nut butters

27. Dried mushrooms (in truffle oil puree)

28. Crested geckos

29. Pistachios

30. Wheat flour

31. Powdered meal supplements

32. Soy nut butter

Genome Sequencing Era

WGS making the microbial “landscape” look like a different Universe

Milky Way light vs radio telescope

Outbreak of Listerios is Linked to Recalled Stone Fruit

• July 2014 recall receives extensive media coverage

• Many inquiries to CDC FDA & health departments from concerned clinicians & public

• Many of whom had received automated telephone calls informing them that they had

purchased recalled fruit.

• During July 19–31, the CDC Listeria website received >500,000 page views

• Stone fruit isolates obtained from company

– 4 human isolates in 2014 with PFGE match

– Patient 1 ate recalled nectarines & peaches

– Patient 2 ate peaches, possibly recalled ones

– Patient 3 did not eat recalled fruits

– Patient 4 no exposure information available

“Prediction is very difficult, esp. about the future.”

According to Yogi Berra, or Niels Bohr, or Albert Einstein, or Mark Twain, or Somebody

“Cross the river by feeling the stones.“

Deng Xiaoping 邓小平

• What will FDA / FSIS do? Swab-a-thons?

• What will CDC & state health departments do?

o Recall may trigger Outbreak investigation, instead of vice versa

• Will epidemiologists be responding more to a “food” signal?

o Long-tail, “never-ending” outbreak?

• “Outbreaks” are a “continuous variable”

o Definition of an outbreak changing?

• Greater than expected?

Source: Art Liang’s speculation

Future foodborne outbreaks more likely to be

• Dispersed in space: Multi-state, multi-national

• Dispersed in time: Multi-year

• Detected by sequence-based surveillance

• Detected as contaminated product first

Associated with

• Fresh produce & minimally processed foods

• Imported foods

• Novel food vehicles

• Novel routes & pathways of contamination

More dispersed & smaller: “low & slow”

Robert Tauxe, MD, Director, CDC Division of Foodborne, Waterborne & Environmental Diseases,

September 20, 2017

Projected wgMLST database validation & deployment

timeline

Apr 14 Oct 14 Apr 15 Oct 15 Apr 16 Oct 16 Apr 17 Oct 17 Apr 18 Oct 18 Apr 19

Development & internal validation

Deployment

Development & internal validation

Deployment

Development & internal validation

Deployment

Development & internal

validation

Deployment

Development & internal

validation

External validation

← External validation

← External validation

Listeria

monocytogenes

Campylobacteraceae

&

Shiga toxin-

producing

E. coli (STEC)

Salmonella

Vibrio, Shigella &

other diarrheagenic

E. coli

Cronobacter &

YersiniaExternal validation →

← External validation

Food Microbiology

“…in this place it takes all the running you can do, to keep in the same place.“

- Red Queen to Alice in Through the Looking Glass

Thank You!