Chapt 8-9 Pathological Protein Rhiannon

The Pathological
Protein, Chapters 8-9
Rhiannon Aguilar
March 27, 2014
Chapter 8: Consuming Fears
● Peter Stent’s cow 133- Dec 1984
● David Bee, veterinarian-- kidney infection? toxin?
● Connection to scrapie- Nov 1986- Gerald Wells
● Confidential government memo
Tracking the Source
● John Wilesmith, head of epidemiology at CVL
o Joined team doing investigation
● Transmissibility confirmed 1988
● Familiar statistics
● “All appeared to be index cases”- had MBM in
Chapter 8, Part II
Forced Cannibalism
● OPEC raised oil prices, encouraged efficiency
● Rendering- process around for centuries
o Offal, downer cows, pets, roadkill
o Solvent extraction vs centrifugation
● Scrapie transfer to cows through rendered meat?
o Lacey/Dealler- not likely
o Taylor- solvent extraction does not destroy
 Reduced 10x infectivity- threshold amount?
 Gabriel Horn 2001
● 7/10 calves die from 1g infected brain
Chapter 8, Part III
Tackling an Epidemic
● Sir Southwood’s low-key “working party”
● 1988 ruminant feed ban, 1994 mammalian protein
● Lots of skepticism on all sides, little urgency
● Mandated slaughter, 50% compensation
● Final report, 1989
o “We wanted to point out that there were enormous
uncertainties. And that if these uncertainties turned out to be
more likely than we had judged there could be catastrophic and
very profound consequences”
● BSO ban, import restrictions
Chapter 8, Part IV
Mad Max
● 5 y/o siamese cat died 1990 w/ TSE symptoms
● Public freak-out!
● Wake-up call
o 1990 House of Commons investigation
o Formed SEAC
o Species jump confirmed
The Watcher
● CJD Surveillance unit, Robert Will
● ~½ of investigated cases not CJD
● “People forget, prion diseases in animals had never caused any
problems in humans as far as we knew, despite extensive
● Different take on Vicky Rimmer
Chapter 8, Part V
Approaching the Watershed
● Back to the Churchills- Narang’s BSE test?
● Suddenly many young CJD victims- statistically
significant- 10 cases 1994-1996
● 1995- realized 1989 offal ban was ineffective, new ban
● “Floral” plaques
● March 20, 1996- Stephen Dorrell announcement
● Disease naming?
● Inquiry, 1998-2000
● Hindsight is 20/20
Florid Plaques
A. florid plaque surrounded
by small areas of spongiform
change in the occipital cortex
(Luxol-PAS stain). B. Multiple
small cluster plaques in the
occipital cortex (Luxol-PAS
stain). C. kuru-type plaque in
the cerebellar cortex (LuxolPAS stain). D.
Immunohistochemistry for
prion protein (using
monoclonal antibody 3F4)
shows strong staining of
plaques in the occipital
cortex, along with
amorphous and pericellular
“The first case of variant Creutzfeldt-Jakob disease in the Netherlands”,
Sánchez-Juan, P. et. al., Journal of Neurology 2007.
Chapter 9: Mad Cow’s Human Toll
● 1992/1993- Epidemic height
● BAB and BARB cows concerning
Calculating Mortality
● No exact proof that BSE causes vCJD
● Try to calculate # of cows with BSE
o Anderson/Donnelly back-calculation parameters
● Study to determine most risky organs -> more bans
● Investigating features of vCJD- incubation time,
victim characteristics, necessary dose, genetics
Chapter 9, Part II
Mad Sheep Disease?
● Origin- sheep or beef?
● Botched study of scrapie and BSE-sensitive mice
Spreading the Madness
● Hilary Pickles- import/export worries
● BSE spread from UK
o Japan - > portrayed differently than last book
o 92% M/M, means vCJD epidemic would be
● Dec 2002, 22 countries with BSE
● Banning more risky (?) practices
Chapter 9, Part III
Practice of bans is spotty
Lasting economic impacts
Developing countries probably have BSE…
Category rating system
o Category I - IV
o USA = Cat II
World Organisation for Animal Health