progress and challenges in decreasing foodborne illnesses in the united states patricia m. griffin,...

Progress and challenges in decreasing foodborne illnesses

in the United States

Patricia M. Griffin, M.D.Chief, Enteric Diseases Epidemiology BranchDivision of Foodborne, Bacterial and Mycotic Diseases National Center for Zoonotic, Vectorborne and Enteric DiseasesApril 12, 2008 Who’s Minding the Store? Seattle, Washington

Foodborne illnesses United States

Estimates for 1997• 76 million ill• 300,000 hospitalized• 5,000 deaths

Healthy People 2010 targets: 50% reduction (from 1997 to 2010) in• E. coli O157 • Campylobacter• Salmonella• Listeria

Mead et al., EID 5:707-25, 1999

Major known foodborne pathogens, 2008 Bacteria

• Bacillus cereus• Brucella• Campylobacter• Clostridium botulinum• Clostridium perfringens• E. coli O157• E. coli, non-O157 Shiga toxin-producing• E. coli, other diarrheagenic• Listeria monocytogenes• Mycobacterium bovis• Salmonella Typhi• Salmonella non-typhoidal• Shigella• Staphylococcus• Streptococcus• Vibrio cholerae, toxigenic• Vibrio vulnificus

Bacteria (continued)• Vibrio, other• Yersinia enterocolitica• Yersinia pseudotuberculosis

Parasites• Cryptosporidium• Cyclospora• Giardia• Toxoplasma• Trichinella• Trypanosoma cruzii

Virus• Caliciviruses• Rotavirus• Astrovirus• Hepatitis A• Hepatitis E

• Prions Fungus

• Aflatoxin-producing

Major known foodborne pathogens, 2008 Bacteria

• Bacillus cereus• Brucella• Campylobacter• Clostridium botulinum• Clostridium perfringens• E. coli O157• E. coli, non-O157 Shiga toxin-producing• E. coli, other diarrheagenic• Listeria monocytogenes• Mycobacterium bovis• Salmonella Typhi• Salmonella non-typhoidal• Shigella• Staphylococcus• Streptococcus• Vibrio cholerae, toxigenic• Vibrio vulnificus

Bacteria (continued)• Vibrio, other• Yersinia enterocolitica• Yersinia pseudotuberculosis

Parasites• Cryptosporidium• Cyclospora• Giardia• Toxoplasma• Trichinella• Trypanosoma cruzii

Virus• Caliciviruses• Rotavirus• Astrovirus• Hepatitis A• Hepatitis E

• Prions Fungus

• Aflatoxin-producing

* Green = recognized as foodborne in past 30 years

Major identified foodborne pathogens, 2008 Bacteria

• Bacillus cereus• Brucella• Campylobacter*• Clostridium botulinum• Clostridium perfringens• E. coli O157*• E. coli, non-O157 Shiga toxin-producing*• E. coli, other diarrheagenic*• Listeria monocytogenes*• Mycobacterium bovis• Salmonella Typhi• Salmonella non-typhoidal• Shigella• Staphylococcus• Streptococcus• Vibrio cholerae, toxigenic*• Vibrio vulnificus*

Bacteria (continued)• Vibrio, other*• Yersinia enterocolitica*• Yersinia pseudotuberculosis*

Parasites• Cryptosporidium*• Cyclospora*• Giardia*• Toxoplasma*• Trichinella• Trypanosoma cruzii*

Virus• Caliciviruses*• Rotavirus*• Astrovirus*• Hepatitis A• Hepatitis E*

• Prions* Fungus

• Aflatoxin*

Yellow = “Home” of organism is the animal kingdom

Topics National networks

• National surveillance• FoodNet

• Overview• E. coli O157• Campylobacter• Salmonella

• PulseNet• OutbreakNet

• Overview• Some recent outbreaks• Example: Salmonella outbreak

Attribution project Progress and challenges

Topics National networks

• National surveillance• FoodNet

• Overview• E. coli O157• Campylobacter• Salmonella

• PulseNet• OutbreakNet

• Overview• Some recent outbreaks• Example: Salmonella outbreak

Attribution project Progress and challenges

FoodNet Sites, 2008Population 45.5 million (15% of U.S. population)

FoodNet

Although all 50 states conduct surveillance for foodborne pathogens,• methods and data quality vary

Need accurate counts of illnesses to measure trends FoodNet sites have extra resources

• to get reports from clinical labs when ill people submit a specimen (usually stool) for testing, and

• to submit those reports to CDC FoodNet measures trends in common foodborne pathogens

• Issues an annual “report card” (MMWR April 11, 2008)

Surveillance data

Surveillance data is the “tip of the iceberg”

Pyramid of Surveillance

Population exposed

Person becomes ill

Person seeks care

Specimen obtained

Lab tests for pathogen

Pathogen isolated

Reported to health department

Pyramid of Surveillance

Population exposed

Person becomes ill

Person seeks care

Specimen obtained

Lab tests for pathogen

Pathogen isolated

Reported to health department

} Population survey

Active surveillance

Clinical lab survey

Topics National networks

• National surveillance• FoodNet

• Overview• E. coli O157• Campylobacter• Salmonella

• PulseNet• OutbreakNet

• Overview• Some recent outbreaks• Example: Salmonella outbreak

Attribution project Progress and challenges

Sequence of events in E. coli O157 infection

E. coli O157 ingested

3 - 4 days

non-bloody diarrhea, abdominal cramps

5 - 6 daysresolution

92% 8%

HUS

bloody diarrhea

1 - 2 days80%

Mead. Lancet 1998

Hemolytic uremic syndrome (HUS)

Kidney failure, anemia, blood clotting problems

Affects persons of all ages• most common in <5 years old and elderly

~5% die

E. coli O157 infections, incidence by year, FoodNet, 1996-2007

0

0.5

1

1.5

2

2.5

3

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007

Year

Inci

denc

e pe

r 10

0,00

0 p

opul

atio

n

National objective

1.20

0.90

Healthy People 2010 Objective: 1.0 illness/100,000 persons

00.10.20.30.40.50.60.70.80.9

1

2000 2001 2002 2003 2004 2005 2006 2007

Percent of USDA ground beef samples that yielded E. coli O157:H7, 2000-2007

% positiveOutbreak investigation resulted in recall of18 million pounds ground beef

Source: www.fsis.usda.gov

E. coli O157 infections, incidence by year, FoodNet, 1996-2007

0

0.5

1

1.5

2

2.5

3

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007

Year

Inci

denc

e pe

r 10

0,00

0 p

opul

atio

n

National objective

1.20

0.90

Healthy People 2010 Objective: 1.0 illness/100,000 persons

Topics National networks

• National surveillance• FoodNet

• Overview• E. coli O157• Campylobacter• Salmonella

• PulseNet• OutbreakNet

• Overview• Some recent outbreaks• Example: Salmonella outbreak

Attribution project Progress and challenges

Campylobacter

Common cause of foodborne illness• diarrhea• paralysis is rare complication

Most illnesses from chicken• that is undercooked, or• that contaminates other foods

Campylobacter infections, incidence by year, FoodNet, 1996-2007

0

5

10

15

20

25

30

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007

Year

Inci

denc

e pe

r 10

0,00

0 p

opul

atio

n

National objective

12.78

Healthy People 2010 Objective: 12.30 illnesses/100,000 persons

Topics National networks

• National surveillance• FoodNet

• Overview• E. coli O157• Campylobacter• Salmonella

• PulseNet• OutbreakNet

• Overview• Some recent outbreaks• Example: Salmonella outbreak

Attribution project Progress and challenges

Salmonella

Common cause of foodborne illness

• diarrhea

• severe illness in vulnerable populations Carried by all food animals Foodborne illness mainly from

• foods of animal origin

• vegetables contaminated with fecal matter from animals

Salmonella infections, incidence by year , FoodNet, 1996-2007

0

2

4

6

8

10

12

14

16

18

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007

Year

Inci

denc

e pe

r 10

0,00

0 p

opul

atio

n

National objective

14.92

Healthy People 2010 Objective: 6.8 illnesses/100,000 persons

Percent change in the incidence of bacterial infections in 2007compared with the previous 3 years (2004-2006), FoodNet

No change

Increase

Decrease

Pe

rce

nt

ch

an

ge

Percent change estimate

95% confidence interval

Graph Interpretation

No significant change = The 95% confidence interval is both above and below the “no change” line

Significant increase = The estimate and the entire 95% confidence interval are ABOVE the “no change” line

Significant decrease = The estimate and the entire 95% confidence interval are BELOW the “no change” line

-100

-80

-60

-40

-20

0

20

40

60

80

100

Campylobacter Listeria Salmonella Shigella STEC*O157 Vibrio Yersinia

Topics National networks

• National surveillance• FoodNet

• Overview• E. coli O157• Campylobacter• Salmonella

• PulseNet• OutbreakNet

• Overview• Some recent outbreaks• Example: Salmonella outbreak

Attribution project Progress and challenges

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 sent to database at CDC

• Reviewed daily at CDC

• available on-demand to participants

PulseNet searches for clusters

Cluster of indistinguishable patterns

•State health departments submit patterns electronically•CDC and State labs search for similar patterns in past 2-4 months•compare patterns visually

•When cluster identified, PulseNet contacts epidemiologists

Topics National networks

• National surveillance• FoodNet

• Overview• E. coli O157• Campylobacter• Salmonella

• PulseNet• OutbreakNet

• Overview• Some recent outbreaks• Example: Salmonella outbreak

Attribution project Progress and challenges

CDC 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

Mission • Ensure rapid, coordinated detection & response to multi-

state enteric disease outbreaks• Promotes comprehensive outbreak surveillance

CDC OutbreakNet Team (continued)

Works in partnership with PulseNet

Involves collaborations between CDC and• State and local health departments

• U.S. Department of Agriculture (USDA) Food Safety and Inspection Service (FSIS)

• U.S. Food and Drug Administration (FDA)

Outbreaks

Outbreaks that we find and solve are the “tip of the iceberg”

We investigate outbreaks

• To take immediate action to protect people

• To learn how to prevent similar occurrences

Topics National networks

• National surveillance• FoodNet

• Overview• E. coli O157• Campylobacter• Salmonella

• PulseNet• OutbreakNet

• Overview• Some recent outbreaks• Example: Salmonella outbreak

Attribution project Progress and challenges

Lettuce at Mexican-style fast food chain

Snack food with vegetable coating

Topics National networks

• National surveillance• FoodNet

• Overview• E. coli O157• Campylobacter• Salmonella

• PulseNet• OutbreakNet

• Overview• Some recent outbreaks• Example: Salmonella outbreak

Attribution project Progress and challenges

Increase in Salmonella Tennessee illnesses

August to December 2006• gradual increase in ill persons over expected

number December 2006

• epidemiologists interviewed some ill persons• found no common exposures

States where patients with the outbreak strain of Salmonella Tennessee lived (as of December 1, 2006)

PulseNet found more than the expected number of this strain of Salmonella

States where patients with the outbreak strain of Salmonella Tennessee lived (as of December 1, 2006)

PulseNet found more than the expected number of this strain of Salmonella

Most states had only 1-2 ill persons

Illnesses continued to increase

January 2007• interviewed 31 ill persons with long questionnaire

• consumed peanut butter and turkey more often than general population• Interviewed 6 people with open-ended questions

• suspected a brand of peanut butter February 2007

• designed questionnaire focusing on peanut butter (brand, quantity)

• interviewed ill and well persons• peanut butter statistically linked to illness

– only Brands A and B

Actions

February 13, 2007 • notified Food and Drug Administration (FDA) • found that brands A and B produced at same plant• distributed to 50 states and ~70 countries

Next day• plant ceased all production

Voluntary recall of all products

35 jars (opened and unopened) yielded outbreak strain

Peanut butter testing after recall

Investigation of plant

Two environmental samples yielded outbreak strain

Leaky roof and faulty sprinkler in summer • timing coincided with start of outbreak• moisture in processing plants favors growth of

Salmonella

0

5

10

15

20

25

30

35

40

7 /2 3

Week illness began

Nu

mb

er o

f C

ases

Product Recall: February 14, 2007

Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul2006 2007

Contaminated jars produced July 2006 – January 2007

Persons with Salmonella Tennessee infection, by onset week, August 2006 – July 2007 (N=532)

None 10 – 191 – 9 ≥ 20

Persons with Salmonella Tennessee infection, by state, August 2006 – July 2007

(N=714 persons ill)

Summary of peanut butter outbreak Diffuse national outbreak

• Detected by routine Salmonella surveillance, enhanced by PulseNet subtyping

Required intensive multi-state investigation First U.S. outbreak linked to peanut butter Product recall based on epidemiologic findings Contamination at plant over many months

Points out the importance of controlling contamination in processed ready-to-eat foods

Topics National networks

• National surveillance• FoodNet

• Overview• E. coli O157• Campylobacter• Salmonella

• PulseNet• OutbreakNet

• Overview• Some recent outbreaks• Example: Salmonella outbreak

Attribution project Progress and challenges

Attribution project

How much foodborne illness is from each food commodity, e.g., beef, eggs, vegetables?

Using outbreak data to make estimates Preliminary data indicates that more illnesses due to

known pathogens are acquired by consuming vegetables than any other commodity• leafy greens an important concern

Outbreaks caused by leafy greens,1973–2006

(N=219)

Lettuce 66%

Cabbage 22%

Fresh herbs 8%

Broccoli 1%Spinach 3%

Herman, Lynch, CDC, unpublished

0%

2%

4%

6%

8%

10%

1981-1985 1986-1990 1991-1995 1996-2000 2001-2005

Year

Proportion of outbreaks due to consumpton of leafy greens, 1981–2005

Source: USDA/Economic Research Service. Data last updated Feb. 15, 2007.http://www.ers.usda.gov/Data/FoodConsumption/FoodAvailSpreadsheets.htm

Denominator is outbreaks with known food vehicle

% of outbreaks

Topics National networks

• National surveillance• FoodNet

• Overview• E. coli O157• Campylobacter• Salmonella

• PulseNet• OutbreakNet

• Overview• Some recent outbreaks• Example: Salmonella outbreak

Attribution project Progress and challenges

Progress in the past 10 years

Much better systems for detecting and investigating foodborne illnesses• FoodNet• PulseNet• OutbreakNet

Declines in incidence of several pathogens, e.g.,• E. coli o157• Campylobacter

Progress in the past 10 years (continued)

Improved safety of some foods, e.g.,• ground beef less contaminated• fewer outbreaks from shell eggs• fewer outbreaks from juice• increased attention to ready-to-eat foods, e.g.,

peanut butter Developing methods to attribute foodborne

illnesses to food commodities

Some of the challenges

Salmonella infections have not decreased• widespread in food animals

Campylobacter from live chickens contaminates retail chicken

Complex ecologies in farming areas link food animals with vegetable fields• food animal manure contaminates

vegetables consumed raw

Foodborne diseases in the 21st century

Attention to ecologies of foodborne agents Many foodborne agents live in animals’ intestines Many foodborne agents can survive in outdoor environments

and processing plants Food safety needs to be an integral part of farming practice

Food concerns, e.g., Produce consumed raw Processed foods, e.g., peanut butter, pot pies, snacks New food products and processes every year

pic

Foodborne diseases in the 21st century (continued) More diffuse, multi-state and multi-national outbreaksStrong public health capacity for surveillance and response

needed to identify problems assure that knowledge of safety gaps from outbreak

investigations are applied throughout industry

The fall and rise of Salmonella infections, United States, 1920-2004

0

510

15

2025

30

35

4045

50

1920 1930 1940 1950 1960 1970 1980 1990 2000

Years

Inci

den

ce p

er 1

00,0

00 p

op

ula

tion

Typhoid fever Non-typhoid salmonellosis

CDC, National Notifiable Diseases Surveillance data

Prevented contamination of food and water with human sewage

Increasing contamination of food and water with animal manure

Challenge: provide safe feed and water to food animals and plants

?

Acknowledgments

State and Local Health Departments & Public Health LaboratoriesAlabama Louisiana North DakotaAlaska Maine OhioArizona Maryland OklahomaArkansas Massachusetts OregonCalifornia Michigan PennsylvaniaColorado Minnesota Rhode IslandConnecticut Mississippi South CarolinaDelaware Missouri South DakotaFlorida Montana TennesseeGeorgia Nebraska TexasIdaho Nevada VirginiaIllinois New Hampshire VermontIndiana New Jersey WashingtonIowa New Mexico WisconsinKansas New York West VirginiaKentucky North Carolina Wyoming

The findings and conclusions in this presentation are those of the author(s) and do not necessarily represent the views of the Centers for Disease Control and Prevention.

Other major CDC contributors Fred Angulo Christopher Braden Patricia M. Griffin Karen Herman John Painter Anandi Sheth Robert V. Tauxe Ian Williams

The conclusions and opinions expressed herein are those of the presenter and do not necessarily represent the views or policies of CDC or DHHS

Acknowledgments (continued)

Major CDC contributors to peanut butter investigation Tracy Ayers Cheryl Bopp Gwen Ewald Peter Gerner-Smidt Olga Henao Mike Hoekstra Mike Lynch Manoj Menon Laura Moyer Thai-An Nguyen Katherine Niksich Nehal Patel Nancy Puhr Anandi Sheth Samir Sodha Kathleen Wannemuehler

FDAUSDA

FoodNet:http://www.cdc.gov/foodnet

PulseNet:http://www.cdc.gov/pulsenet

Foodborne outbreak surveillance:http://www.cdc.gov/foodborneoutbreaks

CDC Safe Water System:http://www.cdc.gov/safewater

General Information About Diseases:http://www.cdc.gov/health

Our websites

Thank you

The findings and conclusions in this presentation are those of the author and do not necessarily represent the views of the Centers for Disease Control and Prevention