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Alternative Career Pathways
John D. Tilden, DVM, MPH
Food Safety Epidemiologist
Michigan Department of Agriculture
“We must be architects of change and not it’s victims”
Don Gingrich, Iowa pork producer
Overview
• My Career Pathway
• The Information Explosion
• Field Epidemiology Investigations
• Lessons Learned
Graduation Day: My Plans
• Large animal herd health
• Maybe some mixed animals
• Definitely no:– pigs– poultry– research– more schooling
Timeline
• 1983 MSU
• 1983-1985 Mixed Animal Practice, Frederick, MD
• 1985-1986 School of Aerospace Med., San Antonio, TX
• 1986-1989 United States Air Force (MI)
• 1989-1990 Johns Hopkins University (MD)
Timeline (continued)• 1990-1991 USDA, APHIS, Washington, DC
(Food Safety Policy)
• 1991-1993 USDA, APHIS, Puerto Rico(International Development,)
• 1993-1995 Epidemic Intelligence Service, CDC
• 1995-1996 Pseudorabies Eradication, S.W. Michigan
• 1996-Present Food Safety Epidemiologist
Emerging Threats and the Information Explosion
• Data saturation
• Tendency to specialize
• Potential career springboard– funding source for further
education– Positions created to address
newly identified needs
Food Safety Disciplines
• Biology
• Epidemiology
• Microbiology
• Public Health
• Animal Health
Laboratory Evidence:PFGE Analysis
* * * * * * * * * *
* * * * * * * * * *
Epidemiology
• The study of the distribution and determinants of diseases and injuries in populations.
Dr. John Snow, September, 1854
Exposure
+
+
-
- Total
9 0
0 3
9 3
9
3
12
Fisher’s Exact p value = .005
Disease
Statistical Evidence
The Centers for Disease Control and Prevention
• Part of the U.S. Department of Health and Human Services
• Initiated in the 1940’s to control malaria in southern states
• Grew and evolved– disease outbreaks– effective treatment– education– prevention strategies
Current CDC Structure• National Center for Infectious Diseases
• National Center for Health Statistics
• National Center for Environmental Health• National Center for Injury Prevention and Control• National Institute for Occupational Safety and
Health (NIOSH)
Why Conduct Field Investigations?
• Increase understanding of disease
– “natural experiments”
• Assist prevention efforts
• Political pressure
Or Tip of an Iceberg?
Isolated Snow Flake?
Checking out apparently isolated cases:
6/27 8/2 9/6 10/11 11/15 12/20 1/24 2/27 4/30123456789
101112
Date
Nu
mbe
r of
Pat
ien
ts
Recall Usual listerosis incubation period
Fatal
Non-fatal
Multistate Outbreak of Listeriosis, United States, 1998-1999
PlantConstruction
Disease Investigations
• Citizens• Private practitioners• Local department of public
health
• State government
• CDC
• Universities
Numberof
Cases
Thum
bnail sketch of field epidem
iologic investigations
1. Receive rep ort of disease
2. Con fi rm
diagn osisC
ase Stu
dy
3. Determ
ine i f i ncrease d potent ial fo r disease t ransmission ex ists
4. Interve nt io n warra nted?
5. Further in vest igat io n w
arra nted?
6. Add it ion al case finding
Case S
e rie s
•Fo rm
ulate a case d efin it ion•D
escript ive analysi s of cases (person -p la ce-time)
•Hypo thesi s g enerat ion
7. Interve nt io n warra nted?
8. Test h ypo th esis vi a ana ly ti c epide m
io lo gic stu dies
•cohort stu
die s (exam
ple: foodb orne i l ln ess o utbreak s)•case -c on
tro l stud
ies (example: rare d ise ase in vest igat io ns)
9. Interve nt io n warra nted?
10 . Di ssem
ina te informat ion
•Prese ntat io ns
•Pu bl icat io ns
Cryptosporidium• 1907: First described• 1976: First human case• 1981: First AIDS patient diagnosed• 1983: Person-to-Person transmission• 1984: Waterborne transmission (Well)• 1987: Waterborne transmission (Surface)• 1988: Waterborne transmission (Pool)• 1993: March 1993 - 403,000 ill in Milwaukee• 1993: August - 7 ill in Madison, WI
Non-Foodborne Routes of Disease Transmission
E. coli 0157:H7• 1982: First recognized as a foodborne pathogen
• 1984: Person-to-person transmission
• 1985: Association with HUS Documented
• 1990: Waterborne transmission
• 1991: Acid tolerance: apple cider
• 1992: Most common cause of bloody diarrhea
• 1993: Heat resistance
• November 1994 - 17 ill in Seattle, WA
Lessons Learned
• If its not fun, its not epidemiology
• Ride the Funding Waves
• Never Say Never
• Stick to What You Care About
Lessons Learned
• Freedom to change is important
• Keep your options open
“Progress is the activity of today that ensures a tomorrow”
Ralph Waldo Emerson
