The Pathological Protein, Chapters 8-9

Rhiannon AguilarHONR299JMarch 27, 2014

Chapter 8: Consuming Fears

Introduction● 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

common

Chapter 8, Part II

Forced Cannibalism● OPEC raised oil prices, encouraged efficiency● Rendering- process around for centuries

o Offal, downer cows, pets, roadkillo Solvent extraction vs centrifugation

● Scrapie transfer to cows through rendered meat?o Lacey/Dealler- not likelyo Taylor- solvent extraction does not destroy agent

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 IVMad Max

● 5 y/o siamese cat died 1990 w/ TSE symptoms● Public freak-out!● Wake-up call

o 1990 House of Commons investigationo Formed SEACo 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 exposure”

● 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

“The first case of variant Creutzfeldt-Jakob disease in the Netherlands”, Sánchez-Juan, P. et. al., Journal of Neurology 2007.

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 (Luxol-PAS stain). D. Immunohistochemistry for prion protein (using monoclonal antibody 3F4) shows strong staining of plaques in the occipital cortex, along with amorphous and pericellular deposits

Chapter 9: Mad Cow’s Human Toll

Introduction● 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 booko 92% M/M, means vCJD epidemic would be

worse?● 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 - IVo USA = Cat II

http://www.oie.int/en/animal-health-in-the-world/official-disease-status/bse/en-bse-carte/World Organisation for Animal Health