5 Prion Diseases

Essential: Cannot generate ourselves
Nonessential: The body can produce them on its own, even if not consumed in the diet

What is the difference between essential and nonessential amino acids?

Prions

A protein that has been misfolded in multiple, structurally distinct ways, at least one of which is transmissible to other proteins

Nonpathogenic, protect cells from oxygen deficiency

What are "normal" prions? What do they have roles in?

Prion

Which is smaller, a prion or a virus?

Prions lack nucleic acid

What makes prions a unique pathogen? What are they lacking compared to viruses, bacteria, and fungi?

They are resistant to procedures that break down nucleic acids

What is good about prions lacking nucleic acids?

Prions do NOT stimulate an immune response because they are simply misfolded protein

Do prions stimulate an immune response? Why or why not?

Cannot directly reproduce

Because prions are missing nucleic acid, what can they NOT do?

They stimulate normal cellular protein to refold into PrPsc

Because prions cannot directly reproduce, how do they replicate instead?

Scrapie

What was the first recognized prion disease (TSE)?

Disinfectant, heat, UV and ionizing radiation, formalin

What normal disinfection methods are prions highly resistant to?

Incineration

What is one of the only disinfection method which can DESTROY prions?

Deactivate into a sterile alkaline solution in an alkaline hydrolysis digester

How do you dispose of prion infected carcasses?

Chronic wasting disease (CWD)

What TSE's are present in deer, moose, and elk?

Feline spongiform encephalopathy

What TSE's are present in wild and domestic cats in Europe?

Transmissible spongiform encephalopathy

What does TSE stand for?

There is direct effect on agriculture with a potential effect on human populations (maybe zoonotic)

Why are we concerned about CWD?

Bovine spongiform encephalopathy (mad cow)

What TSE's are present in cattle?

Transmissible mink encephalopathy, mink spongiform encephalopathy, mink scrapie

What TSE's are present in ferrets?

Transmissible sheep encephalopathy, sheep (goat) scrapie

What TSE's are present in sheep?

Itching and rubbing to point of self mutilation, wool pulling, staggering, hypersensitive to light and movement, tremor, weight loss despite retention of appetite

What are some typical clinical signs of scrapie?

Using a scrapie flock certification program

What is one of the ways the USA reduces the liklihood that scrapie will spill over to humans?

Bovine spongiform encephalopathy

This is a chronic progressive degenerative and fatal disease affecting the central nervous system of cattle

Recognize in Great Britain with hundreds of thousands affected with the peak in 1992

What was the prevalence of BSE like in the 1980s? What country was it recognized in?

Less than 1 case per million head worldwide

What is the prevalence of BSE like today?

Creutzfeldt-Jakob disease (CJD), Kuru, Variant CJD (vCJD)

What 3 TSE variants are present in humans?

Kuru disease (laughing sickness)

This disease is caused by infectious prions in contaminated human brain tissue, spread initially by people in New Guinea who practiced a form of cannibalism as part of their ritualistic funeral procession.

vCJD

Human prion disease associated with consumption of BSE infected beef

ONLY definitive: postmortem histopathology in brain tissue
Presumptive: diagnosis based on clinical signs

What is the ONLY definitive diagnosis for TSE? Presumptive?

UK

What country is BSE and vCJD most prevalent in?

Because they have the potential to be carrying BSE prion (vCJD in humans) and do not want to spread it

Why are people who lived in Europe in the late 1980's and 90's (even if they live in America now) barred from giving blood to wounded troops?

It has costed us around $30 BILLION in lost exports over only 3 cows. We even did not take beef from the UK to try and feed victims of Hurricane Katrina.

What kind of economic impact has BSE had on America's beef industry?

Temperament changes (nervous, aggressive), abnormal posture, incoordination/difficulty rising, loss of condition but same appetite

What are some symptoms of BSE in cattle?

2-8 years

What is the incubation period for BSE in cattle?

NO TREATMENT OR VACCINE

What is the vaccine and treatment scene like for BSE?

NO (even if we KNOW cow is infected)

Can BSE be transmitted in milk to humans?

Feed ban: prohibit feeding food animals back to OTHER food animals

What is the primary animal health protective measure against BSE?

To other cattle

The BSE feed ban is the most important measure to prevent transmission to what demographic?

Before foodban: rapid explosion
Foodban in 1988
After foodban: dramatic 99% reduction in cases since 1992

Since the foodban, what has the transmission of BSE been like in other cattle?

Referendum in UK (deciding whether or not to leave European Union, Brexit) exactly reflected countries affected by BSE (basically countries who had BSE present within their country decided to leave the European Union)

The ultimate "Politicization of Public Health" was revolved around BSE in what way?