Arthur P. Liang, MD, MPH
Director, Food Safety Office
National Center for Infectious Diseases
Centers for Disease Control & Prevention
We are not losing the “war.”
Unfortunately, we probably can’t win it either.
Food Safety folks will always have a job.
|Bronchitis and emphysema||4.2|
|Pneumonia and influenza||3.5|
It is “time to close the book” on the problem
of infectious diseases. (1969)
Jesse Steinfeld, MD, U.S. Surgeon General, 1969-73
“The future of infectious diseases will be very
Macfarlane Burnet, 1960 Nobel Prize Winner In Medicine
Told students that there were “no new diseases
to be discovered. (1976)”
Lewis Thomas, Dean Yale Medical School
Source: US Institute of Medicine, 1997; WHO, 1999.
(line graph showing that after years of decline, these illnesses are again on the rise.)
(graphic shows connection of hosts, microbes, and environment)
US Manure Estimates, 1997
(map showing geographic distribution of Cattle Fattened on Grain and Concentrates and Sold: 1997)
|Fish, fish products, & shellfish||Fresh fruits||Fresh vegetables||Foreign-grown wheat|
Currently, according to FDA 38% Fruit and 12% vegetables are imported.
Domestic Produce Sampling Program
Contamination Rate: 1.6% (as of July 2001)
(graphic - map of states affected by an outbreak related to cereal)
|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|
1988-92 8 multi-state outbreaks
1993-97 = 30 multi-state outbreaks
’98 = 9
’99 = 8
* FoodNet case-control studies
Previously Identified Risk Factors for Sporadic Infection -Eating at a table service restaurant
E. coli O157 Study, 1999-2000 - Restaurant consumption of pink hamburger was NOT associated with infection
* FoodNet case-control studies
Molecular subtyping "DNA Fingerprinting" (example shown)
PFGE: Strains of patients' isolates, cereal & production line indistinguishable
(PFGE patterns shown from patients, cereal, production line)
PulseNet (1995 TX, MA, MN, WA) E.coli,
Salmonella, Listeria, & Shigella
States in Orange (WA, ID, NV, CA, AK, IL, OH, WV, TN, GA, FL) have RT-PCR capability for NLV & have submitted positive samples to CDC for confirmation & typing
States in Green (ND, MI, IN, MS, ME, VT, NY) have RT-PCR capability, but have not yet submitted positive samples
States in Gray (remaining states) have the protocols for RT-PCR, but have not yet tested outbreak samples
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
(Bar graph. In descending order, Norwalk-like virus, Salmonella, C. perfringens, Giardia, S. aureus)
Where do the microbes come from?
|Agent||# of cases||resevoir||% food|
|Clostridium perfringens||248,520||soil, man, animal||100|
|Giardia lamblia||200,000||Man, animal||10|
|Escherichia coli O157:H7||62,458||cow||85|
Mead, et al, Emerging Infectious Diseases 1999:5(5); 607-625
Emergence of non-typhoid Salmonella: Reported infections USA, 1920-1997 (rising in 1980's/1990's)
23 percent overall drop in 7 bacterial foodborne illnesses since 1996.
"Preliminary FoodNet Data on the Incidence of Foodborne Illnesses -- Selected Sites, United States, 2001" Morbidity & Mortality Weekly Report (April 19, 2002) http://www.cdc.gov/mmwr/
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.
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.
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
“…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
Closing (Florida scene and conference logo)