Warnings that ‘slow-moving disaster’ in North America raises chances of fatal mad cow-type disease jumping species barrier
When the mule deer buck died in October, it perished in a place most humans would consider the middle of nowhere, miles from the nearest road. But its last breaths were not taken in an isolated corner of American geography. It succumbed to a long-dreaded disease in the backcountry of Yellowstone national park, north-west Wyoming – the first confirmed case of chronic wasting disease in the country’s most famous nature reserve.
For years, chronic wasting disease (CWD), caused by prions – abnormal, transmissible pathogenic agents – has been spreading stealthily across North America, with concerns voiced primarily by hunters after spotting deer behaving strangely.
The prions cause changes in the hosts’ brains and nervous systems, leaving animals drooling, lethargic, emaciated, stumbling and with a telltale “blank stare” that led some to call it “zombie deer disease”. It spreads through the cervid family: deer, elk, moose, caribou and reindeer. It is fatal, with no known treatments or vaccines.
That’s rather concerning, but doesn’t really answer what I was asking. I was wondering what eventually ends up destroying prions out in nature, presuming something does (I imagine something must, otherwise after hundreds of millions of years of complex life existing, wouldn’t prions just be absolutely everywhere, making any life using the affected proteins basically impossible?)
Ah! Well you want this one then.
And something to remember, the prions we’re talking about really only came about with the advent of mammals. And we know of only one or two more kinds of prions and that’s about it. But it’s likely that there are prions for all kinds of animals out there and that there is a increase and decrease of particular kinds of prions based on the prevalent animals of the time.
So the PrP family of prions may just be having a recent “in all of life on this planet context” swelling of numbers. And when mammals aren’t around any longer, they’ll see a precipitous decline. Maybe this is some underlying factor that drives some kind of quantum evolution (which is a very controversial idea that evolution has “spikes” that drive rapid evolution from time to time), very likely not but fun to think about at least to me.
Ah, so if Im understanding that correctly, things like weather and microbial activity does destroy them over time, just slowly enough that they can persist at levels reasonably likely to cause infection for a very long time? Now Im sort of wondering just how long its possible to detect them in any concentration for, and if its possible to deduce any kind of useful information about the proteins that they were “supposed” to be from one. Like, given that they arent living things that need food or energy, might there still be a few prions from currently extinct species still around, in places that are free of the things that normally slowly degrade them? Could such prions if found tell us anything useful about the biochemistry of the species that they came from? It also has me thinking about how, if they can get inside plants and transmit that way and also have variants known to affect humans, and given that agricultural fields are both unguarded and impractical to completely monitor, they would make for an absolutely horrific sort of terrorist weapon, but thats not something Id like to contemplate too hard.
It does surprise me to hear that we only know of a few types though. From the (very limited) understanding I had, I had sort of assumed that all proteins had a corresponding prion that represented some sort of lower energy ground state for them that they all had a tiny chance of spontaneously falling into, like, false vacuum decay but for proteins, or something.