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Polio: A Disease on the Brink of Extinction Dr. Clifton FranklundAssociate Professor of Biological SciencesFerris State University
Cause History
Prevention The Future
#3
Key Points
Cause
The Polio Virus
Picornavirus
Very small
RNA genome
Three types
Humans are the only host
Key Points
Cause
The Infectious Cycle
Enteric virus
Tonsil infection
Gut infection
Viremia
Motor neurons
Shed in feces
Key Points
Cause
Result of Infections
95%
4% 1%
AsymptomaticMild SymptomsParalysis
Asymptomatic
Mild disease
Fever
Headache
Stiff neck
Paralysis is rare
Under-reporting
Key Points
History
Polio in Ancient Times
Ancient disease
Egyptian stele
Paralyzed priest
1400 BC
This virus has been around for awhile…
Key Points
History
Polio Comes to the U.S.
First diagnosed cases in the late 1800’s
1916 first large epidemic polio outbreak
Sanitation effort ineffective
Key Points
History
1916 New York Outbreak
New York City
9,000 cases
2,343 deaths
Nationally
27,000 cases
6,000 deaths
Key Points
History
Incidence in the 20th Century
Endemic in US
Seasonal polio outbreaks
July-September
Post-WWII peak
1952 peak: 57,628 cases
Key Points
History
FDR and the March of Dimes
Contracted polio at age 39
Elected president in 1932
NFIP - March of Dimes – established in 1938
Key Points
Prevention
Salk Vaccine
1953
Inactivated virus vaccine (IPV)
Required three injections
Cannot mutate
Only vaccine in USA since 1999
Key Points
Prevention
Polio Vaccine Trials
1954
Nearly two million children
Proven effective in 1955
By 1957 polio incidence was down by 90%
Key Points
Prevention
Cutter Incident
1955
Improperly prepared vaccine
Virus not inactivated
260 polio cases
192 paralyzed
Key Points
Prevention
Sabin Vaccine
1956
Attenuated vaccine (OPV)
Shed in feces
Herd immunity
Main vaccine in USA until 1999
Still main vaccine globally
Key Points
Prevention
Sabin Field Testing
1957 - 1959
Much of the US and Canada already treated
Went to Soviet Union during the Cold War
100,000,000 vaccinated by 1961
Key Points
The Future
#3Eradication of a Pathogen
Smallpox 1976
Rinderpest 2001
Polio ???
Key Points
The Future
#3The Strategy
Rotary Club 1985
Global use OPV
Goal for total eradication by 2000
Last case in USA 1979
Key Points
The Future
#3The Current Picture
Last holdouts for polio
Afghanistan
Pakistan
India
Nigeria
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Dr. Clifton FranklundDepartment of Biological Sciences820 Campus Drive / ASC 2004Big Rapids, MI [email protected](231) 591-2552
Questions?