Prions are scary, for the reason that "all known prion diseases...are untreatable and fatal." How do you stop a prion? For that matter, how do you stop anything in the brain (without cutting it out)?
( http://pipeline.corante.com/archives/2011/11/29/a_things_i_w... )
A bit more about that from a better source: http://www.scientificamerican.com/article/surgical-exposure-...
That sounds like an easy (albeit wasteful) problem to solve.
This article is a bit more optimistic that a combination of screening and better sterilization techniques has reduced the risk to more acceptable levels: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3358170/
"Fragile instruments such as endoscopes and electrodes remain a challenge, but new and gentler methods— alkaline cleaning solutions, phenolics, and gaseous hydrogen peroxide—have proven harmless to instruments and give a high, if not always complete, degree of prion inactivation (24–26)."
My girlfriend at the time was actually really knowledgeable about Creutzfeldt–Jakob. After many, many questions and a some more research on my own, the one consoling thing is that if I had it, by the time the symptoms manifested, I would be too incoherent to really understand what was happening.
While I've certainly lost some cognitive abilities in the intervening decade, I haven't had any symptoms of Creutzfeldt-Jakob. However, I have felt compelled to stop donating blood, and have rescinded my organ-donor status (although I've made it clear to my family members that my body is to me made available for research purposes).
edited: for clarity
No, you can still design chemicals and peptides that could cross the blood brain barrier via adsorptive endocytosis, saturable transporters and trans-membrane diffusion.
Drug Delivery to the Brain: https://en.wikipedia.org/wiki/Drug_delivery_to_the_brain
Modes of Transport: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2697631/