# Presentation: 578071

## Current State of Foodborne Illness

**Arthur P. Liang, MD, MPH**
**Director, Food Safety Office**
**National Center for Infectious Diseases**
**Centers for Disease Control & Prevention**

- Conference for Food Safety Education
- Orlando, Florida
- September 17, 2002

## Conclusions

**We are not losing the “war.”**
**Unfortunately, we probably can’t win it either.**
**Food Safety folks will always have a job.**

## Causes of Death, United States, 1900 

- PERCENT

## Causes of Death, United States, 1992

## “The future of infectious diseases will be very dull. (1972)”  

- Macfarlane Burnet, 1960 Nobel Prize Winner In Medicine

***It is “time to close the book” on the problem of infectious diseases. ****(1969)****  ***
- Jesse Steinfeld, MD, U.S. Surgeon General, 1969-73

***Told students that there were “no new diseases to be discovered. ****(1976)****”  ***
- Lewis Thomas, Dean Yale Medical School

**Notes:**
5 years later the first deaths from what became known as AIDS
Est. 250,000 people were already infected.

## Examples of Pathogenic Microbes Identified Since 1973

- 1973 Rotavirus
- 1977 Ebola virus
- 1977 Legionella pneumophila
- 1980 Human T-lymphotrophic
- 1981 Toxin-producing Staph aureus
- 1982 Escherichia coli O157:H7
- 1982 Borrelia burgdorferi
- 1983 HIV
- 1983 Helicobacter pylori

- 1989 Hepatitis C Virus
- 1992 Vibrio cholerae O139
- 1993 Hantavirus Virus
- 1994 Cryptosporidium
- 1995 Ehrlichiosis
- 1996 nvCJD Prion
- 1997 HVN1 Virus Influenza
- 1999 Nipah Virus

**Source: US Institute of Medicine, 1997; WHO, 1999. **

## Emergence of non-typhoid Salmonella: 
Reported infections  USA, 1920-1997

**Reported infections  USA, 1920-1997**

**Years**

- CDC, National surveillance data

**0**

**5**

**10**

**15**

**20**

**25**

**30**

**35**

**40**

**45**

**50**

**1920**

**1930**

**1940**

**1950**

**1960**

**1970**

**1980**

**1990**

**Incidence per 100,000 population**

- Typhoid

## Emergence of Foodborne Pathogens

**1900**
***Botulism***
***Brucellosis***
*** ******Cholera***
*** ******Hepatitis***
*** ******Scarlet fever (streptococcus)***
*** ******Staphylococcal food poisoning ***
*** ******Tuberculosis***
*** ******Typhoid fever***

**1975-1995**
**Norwalk-like viruses***** ***
***Campylobacter jenjuni***
***Salmonella Enteritidis ***
***Shiga toxin-producing E. coli O157:H7, O111:NM, O104:H21***
***Listeria monocytogenes***
***Clostridium botulinum (*****infant*****)***
***Vibrio cholerae 0139***
***Vibrio vulnificus***
***Yersinia enterocolitica***
***Arcobacter butzleri***
***Hepatitis E***
***Cryptosporidium parvum***
***Giardia lamblia***
***Cyclospora cayetanensis***
***Toxoplasma gondii***
**BSE prion**
***Nitzchia pungens (dinoflagellate)***

**Notes:**
 is our forth point, the emergence of many new kinds of bacteria.

1942:	Only 4 pathogens found in foods.
1975-1995: 	Newly recognized pathogens have dramatically increased.
	14 of these new pathogens are listed here.

## Why Foodborne Diseases Emerge?

- MICROBES

- ENVIRONMENT

**Why Foodborne Diseases Emerge?**

## Microbe factors

**Norwalk-like virus:  person-to-person, hardy, low dose**
***E. coli***** O157:H7 - Acid tolerant**
**Apple cider, salami, mayonnaise **
**Listeria & Yersinia  - refrigeration**
**Antibiotic resistance**

***Factors influencing emergence***

## Environment factors

**Changes in food production**
** ****CAFOs & Manure glut**
** ****Globalization of food supply**
** ****Centralized production**

***Factors influencing emergence***

## Democratic Staff Report, US Senate Agriculture Committee (1998) “Animal Waste Pollution in America, An Emerging National Problem”

- US Manure Estimates, 1997
**5 tons of animal manure / person / year **
**130 times greater than amount of human waste**

## E. coli O157

**Scotland (JE Coia et al, J. Infect 36:317, 1998)**
**Handling / preparing raw food (40%)**
**Gardening / garden play (36%)**
**Lived on / visited farm (20%)**
**Direct / indirect contact with manure (17%)**
**Private H****2****0 supply (12%)**
**Recent high coliform counts in H****2****0 supplies (12%)**

**FoodNet Case-control:**
**Living on or visiting a farm**
**Contact with farm animals**

***Campylobacter**********

**FoodNet Case-control:**
**farm animals**

## Imported Food Consumption on the RiseSource: USDA Agricultural Research Service

**Notes:**
Currently, according to FDA 38% Fruit and 12% vegetables are imported.

## Examples of U.S. outbreaks traced to foods from other countries

- Norwalk-like virus & Raspberries (Europe and Canada)
- Seafood salad on an airplane from Peru caused cholera
- Cyclospora & Raspberries from Guatemala
- Salmonella & OJ from Mexico
- Alfalfa seeds shipped from Netherlands caused *Salmonella* diarrhea in persons who ate alfalfa sprouts

## 1999 FDA Imported Produce Sampling, n=1003

**4.4% positive**
**No *****E. coli***** 0157:H7**
***Salmonella***** - 80% of violations**

**Domestic Produce Sampling Program**** **
**Contamination Rate: 1.6%  (as of July 2001)**

## 215 (65%) of 331 tested patient isolates  from 23 states matched by PFGE

675 cases were reported to PHLIS

432 cases (64%) over expected baseline

**675 cases were reported to PHLIS**
**432 cases (64%) over expected baseline**

**Mass production & distribution**

## Large, multi-state outbreaks

- 1990 Salmonella & Cantaloup			295 infections in 28 states
- 1991 Salmonella & Salads				400 infections in 23 states & Canada
- 1993 	E. coli 0157 in hamburger		>700 cases,  4 died in four states.
- 1994 Salmonella in ice cream			~ 224,000 ill in 41 states
- 1995 S. Stanley in Alfalfa sprouts		242 ill in 17 states
- 1996 Cyclospora & raspberries			>1000 ill,  22 hospitalizations
- 1997 E. coli 0157 & alfalfa sprouts		108 ill in 2 states
- 1998 Listeria in hotdogs				>100 ill, 21 deaths in 21 states
- 1999 Salmonella & OJ					360 ill  in 16 states and Canada
- 2000 Norwalk-like virus & pasta salad	333 ill in 13 states

**Notes:**
1988-92 8 multi-state outbreaks
1993-97 = 30 multi-state outbreaks

## Number of multi-state outbreaks, 1990-1999

**Notes:**
1988-92 8 multi-state outbreaks
1993-97 = 30 multi-state outbreaks
’98 = 9
’99 = 8

## Host factors

** ****Increased numbers of susceptible persons**
**Aging , HIV infection, immunosuppressive drugs**
** ****Changing eating habits**
**Dietary, "fast food“, eating out,...**
** ****Improved surveillance & detection**
** ****Bioterrrorism**

***Factors influencing emergence***

## Changing eating habits

**changes in types of foods consumed:**
**	****turkey, chicken, fruits & vegs, ground beef**
** ****beef, eggs**
**popularity of "fast food" & salad bars**** **
**increased availability of ready-to-eat**
**increased spending outside the home**

## * FoodNet case-control studies

**Eating chicken **_**outside home**_** **
***Campylobacter**********
**Turkey or chicken cooked **_**outside the home**_
**Other meat cooked **_**outside the home**_
*** ****FoodNet case-control studies**

**Eating Habits:  Restaurants?**

## Norwalk-like virus Outbreaks, 1997 – 2000

**Norwalk-like virus Outbreaks, ****1997 – 2000**

**Settings**

**Total: 229**

**38%**

**26%**

**16%**

**10%**

**5%**

**5%**

**Restaurants/ **
**catered events**

**Nursing homes**

**Schools/ daycares**

** ****Vacation/ **
**   ****cruise ships**

**Other**

**Not given**

**Mode of  transmission**

**Total: 172**

## E. coli O157 Study, 1999-2000

Restaurant consumption of pink hamburger was NOT associated with infection

* FoodNet case-control studies

_**Restaurant**_** consumption of pink hamburger was ****NOT**** associated with infection**
*** ****FoodNet case-control studies**

*E. coli** *O157 case-control study, 1996-1997
**Previously Identified Risk Factors for Sporadic Infection**
**Eating at a table service restaurant**

## Improved surveillance & detection 

- Molecular subtyping "DNA Fingerprinting"
- Converts genetic material into a “bar code”
- Identifies hundreds of different strains
- Can be scanned & transmitted electronically

- PFGE: Strains of patients' isolates, cereal & production line indistinguishable

- production
- line

- patients

- cereal

## Improved surveillance & detection 

**Improved surveillance & detection**

**Notes:**
PulseNet (1995 TX, MA, MN, WA) E.coli, Salmonella, Listeria, & Shigella
States in Orange have RT-PCR capability for NLV & have submitted positive samples to CDC for confirmation & typing
States in Green have RT-PCR capability, but have not yet submitted positive samples
States in Gray have the protocols for RT-PCR, but have not yet tested outbreak samples

##  Burden of Foodborne Disease, 21st Century

** ****Estimated 76 million cases**
**resulting in 323,000 hospitalization & 5000 deaths each year in the U.S.**
** ****1 in 4 Americans will develop a foodborne illness**
** ****1 in 1000 will be hospitalized**
** **
** ****Cost: an estimated $6.5 billion per year**
**~CDC Annual budget**

## Most common causes of foodborne IllnessMead et al, 1999

- Most common causes of foodborne IllnessMead et al, 1999

**Notes:**
Restaurant food handling important with Norwalk

## Deaths due to Foodborne Illness 

- Salmonella

- Listeria

- Toxoplasmosis

- Norwalk-like

- Campylobacter

- E. coli 0157

- Other

- 31.0%

- 28.0%

- 21.0%

- 7.0%

- 5.0%

- 3.0%

- 5.0%

## Where do the microbes come from?

| Agent | # of cases | resevoir | % food |
| --- | --- | --- | --- |
| Norwalk-like viruses | 9,200,000 | man | 40 |
| Campylobacter spp | 1,963,141 | poultry | 80 |
| Salmonella, nontyphoidal | 1,341,873 | animal | 95 |
| Clostridium perfringens | 248,520 | soil, man, animal | 100 |
| Giardia lamblia | 200,000 | Man, animal | 10 |
| Staphylococcal | 185,060 | man | 100 |
| Toxoplasma gondii | 112,500 | cat | 50 |
| Shigella spp. | 89,648 | man | 20 |
| Yersinia enterocolitica | 86,731 | pig | 90 |
| Escherichia coli O157:H7 | 62,458 | cow | 85 |

**Mead, et al, *****Emerging Infectious Diseases***** 1999:5(5); 607-625**

## Are we winning the war against foodborne disease?

## Emergence of non-typhoid Salmonella: 
Reported infections  USA, 1920-1997

**Reported infections  USA, 1920-1997**

**Years**

- CDC, National surveillance data

**0**

**5**

**10**

**15**

**20**

**25**

**30**

**35**

**40**

**45**

**50**

**1920**

**1930**

**1940**

**1950**

**1960**

**1970**

**1980**

**1990**

**Incidence per 100,000 population**

## 2001 FoodNet Data

**23 percent overall drop in 7 bacterial foodborne illnesses since 1996.**
**27**%**  Campylobacter**
**15**%**  Salmonella**
**35**%**  Listeria**
**49**%**  Yersinia**
- "Preliminary FoodNet Data on the Incidence of Foodborne Illnesses -- Selected Sites, United States, 2001" Morbidity & Mortality Weekly Report (April 19, 2002)  _[http://www.](http://www.cdc.gov/mmwr/)__[cdc](http://www.cdc.gov/mmwr/)__[.](http://www.cdc.gov/mmwr/)__[gov](http://www.cdc.gov/mmwr/)__[/](http://www.cdc.gov/mmwr/)__[mmwr](http://www.cdc.gov/mmwr/)__[/](http://www.cdc.gov/mmwr/)_.

## Infections Associated with Food, 1900 vs 2000

- _1900s_
-  Botulism
-  Brucellosis
-  Cholera
-  Hepatitis
-  Scarlet fever (streptococcus)
-  Staphylococcal
-  Tuberculosis
-  Typhoid fever

- _2000_
-  Norwalk-like viruses
-  Campylobacter
-  Salmonella
-  Clostridium perfringens
-  Giardia lamblia
-  Staphylococcal
-  Toxoplasma gondii
-  Shigella
-  Yersinia enterocolitica
-  E coli O157:H7

## Addressing Food Hazards in the 21th century

-  Inspection & regulation (GAPs, GMPs, HACCP)
-  Hygienic processing, Water chlorination
-  Refrigeration, safe canning, additives & preservatives
-  Pasteurization, monitoring
-  Medical advances: antibiotics, vaccines
-  Foodhandler education & behavior change

## Tree of Life,

**Tree of Life,**
**circa ****1866 **

**Ernst Haeckel's **

**Notes:**
At the top of Haeckel's tree are Menschen - men, & Haeckel meant white European males.
In middle of his tree are reptiles, & below them amphibians At the base of his tree are single celled amoebas, & "monera" - Haeckel's name for the bacteria.
Haeckel's picture of evolution was a picture of linear progress from bacteria to humans. Indeed, he defines four explicit stages of progress (on the right side of the picture): Protozoa, Invertebrates, Vertebrates, Mammals.

## Woesian Tree of Life

**Notes:**
In terms of bio-diversity, all plants & animals are just twigs compared to the branches that make up micro-organisms. The majority of eukaryotic life is, in fact, microbial (protists). There is far more phenotypic & genotypic diversity in all the protist groups combined than within the plant, animal or fungal kingdoms.

Carl Woese University of Illinios in the late 1970s, Woese wanted to determine evolutionary relationships; using ribosomal RNA 

Bacteria appear about 3.5 billion years ago.  The oldest fossil evidence for anatomically modern humans is about 130,000 years old in Africa, & there is evidence for modern humans in the Near East sometime before 90,000 years ago.

Bacteria can go through 30 generations in a day; this would be equivalent to 1000 years of human evolution.

Bacteria can acquire & spread genetic material laterally via plasmids & transposons.   Through biofilms can form alliances with other bacteria & microorganisms

## Conclusions

**We are not losing**
**Microbes rapidly adapt through biologic evolution, transfer of genes.**
**Microbes appear 3.5 Billion years ago***** ***
***Homo sapien***** adapts through cultural evolution,  transfer of information**
**The World is counting on you to pass down the lessons of civiliztion to this and future generations**
**Once you start you can’t stop**

## The Red Queen Principle - Leigh van Valen (evolutionary biologist, 1973)

**“...****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*

## Est. Foodborne Illnesses (thousands) by etiology,
 Mead et al, 1999

** ****Mead et al, 1999**

## Thinking Globally -- Working Locally

**Thinking Globally -- Working Locally**

**A Conference on **
**Food Safety Education**