Prions Are Forever

Prion diseases are most commonly acquired by inheriting a faulty prion protein gene from a parent, consuming prion-contaminated food, or receiving prion-contaminated donor tissues or organs.

But there is a final disturbing transmission possibility, one that stems from prions' mind-boggling powers of endurance.

Those powers are considerable. According to one account, prions resist digestion by protein-cleaving enzymes, may remain infectious for years when fixed by drying or chemicals, can survive 200°C heat for 1-2 hours, and become glued to stainless steel within minutes. Oh, and they’re also resistant to ionizing radiation.

Why are prions so hard to kill (if kill is even the right word for an evil protein meme)?

No one knows for sure. One expert hypothesized that because our decontamination methods have always targeted DNA and RNA – molecules possessed by all actual living creatures – they are by design not as effective on proteins.

The structure of prions themselves may also lend them supernatural survival powers. Just 3% of a prion protein is composed of beta-sheets, a common fold. But 43% of a prion is so folded. Such a substantial percentage makes the protein highly resistant to degradation, the reasoning goes. The herding of prions into chain-linked amyloid fiber may also protect them from assault.

Whatever the cause, prions are, to put it mildly, good survivors. And that may be why neurosurgical equipment can remain infectious even after it undergoes standard sterilization.

At least 2 cases of prion disease were contracted by people whose implanted depth electrodes had been previously used on a patient with Creutzfeldt-Jakob but were “inadequately” cleaned with benzene and disinfected with 70% alcohol and formaldehyde and sat unused for 2 years prior to implantation. And at least nine other cases of spontaneous Creutzfeldt-Jakob seem likely to have been contracted from inadequately sterilized medical equipment.