Prion diseases are slow to develop (up to decades), incurable, and always fatal.
I think the “always fatal” part of this sentence is vacuous. Unless the meaning is something akin to “kills within X years of contracting the disease”, it can only mean “kills the victim if they don’t die of something else first.” (In fact, the article later says “Humans infected with BSE, meanwhile, can harbor it for up to decades post-exposure, and live an average of over a year after showing symptoms.”)
There are two known infectious prion diseases in people. … Kuru … vCJD
But it doesn’t seem to infect people. Is it ever going to? If a newly-emerged virus were sweeping across the US and killing deer, which could be spread through consuming infected meat, I would think “oh NO.” I’d need to see very good evidence to stop sounding the alarm.
Scrapie, in sheep, has been known since at least 1732, and isn’t thought to spread to humans.
Unless the meaning is something akin to “kills within X years of contracting the disease”, it can only mean “kills the victim if they don’t die of something else first.”
The latter is true of every fatal disease, yes? Alzheimer’s also has a long fuse til death but people don’t recover from it. I’m also told there was a very popular recent television show about a man with terminal cancer who died from other causes.
“Infectious” means “transmissible between people”. As the name suggests, fatal familial insomnia is a genetic condition. (FFI and the others listed are also prion diseases—the prion just emerges on its own without a source prion and no part of the disease is contagious. This is an interesting trait of prions that could not happen with, say, a disease caused by a virus.)
Scrapie, in sheep, has been known since at least 1732, and isn’t thought to spread to humans.
True! I could have talked about scrapie more in this article and didn’t for two reasons-
First, because I looked at some similar transmission tests and it seems to be even less able to convert human PrP.
Second, because as you mention, it’s been around for centuries—if it was going to have spilled over, it probably would have happened by now. CWD, meanwhile, is only a few decades old and has only spread a lot recently- it has more room to explore, so to speak, and some of its possible nearby mutations have never existed around humans before but might now.
As I say in the piece, I think the risk from CWD is in fact low—but this line of reasoning is why human-disease epidemiologists tend to be more concerned about emerging animal diseases than animal diseases that have been around and stable for ages.
“Infectious” means “transmissible between people”. As the name suggests, fatal familial insomnia is a genetic condition. (FFI and the others listed are also prion diseases—the prion just emerges on its own without a source prion and no part of the disease is contagious. This is an interesting trait of prions that could not happen with, say, a disease caused by a virus.)
Can someone catch FFI from coming into contact with the neural tissues of a patient with FFI?
I suspect it’s possible that FFI genes cause the patient’s body to create prions, but can those prions lead to illness in a person without the FFI gene? If yes, then FFI would still be “infectious” in some sense, I suppose.
Possibly if by “come in contact” we mean like ingesting or injecting or something. That’s the going theory for how the Kuru epidemic started—consumption of the brain of a person with sporadic (randomly-naturally-occuring) CJD. Fortunately cannibalism isn’t too common so this isn’t a usual means of transmission. I think if anything less intensive (say, skin or saliva contact) made CJD transmissible, we would know by now. See also brain contact with contaminated materials e.g. iatrogenic CJD, or Alzheimers which I mention briefly in this piece.
it’s possible that FFI genes cause the patient’s body to create prions,
I was thinking of iatrogenic transmissions, yeah (and prions have been a long term psychological fear of mine, too...so I perhaps crawled too much publicly available information about prions to be a normal person)
I wonder if there are any instances of FFI transmitted through the iatrogenic pathway, and whether it is possible to be distinguished from the typical CJD, and whether iatrogenic prions could become a significant issue for healthcare (more instances of prion diseases due to aging population could possibly mean more contaminated medical equipments, and the possible popularisation of brain-computer interface might give us some problems too) given the difficulty of sterilising prions.
Maybe the sample size is too small for us to know.
I think the “always fatal” part of this sentence is vacuous. Unless the meaning is something akin to “kills within X years of contracting the disease”, it can only mean “kills the victim if they don’t die of something else first.” (In fact, the article later says “Humans infected with BSE, meanwhile, can harbor it for up to decades post-exposure, and live an average of over a year after showing symptoms.”)
Wikipedia lists fatal familial insomnia, and two others.
Scrapie, in sheep, has been known since at least 1732, and isn’t thought to spread to humans.
The latter is true of every fatal disease, yes? Alzheimer’s also has a long fuse til death but people don’t recover from it. I’m also told there was a very popular recent television show about a man with terminal cancer who died from other causes.
“Infectious” means “transmissible between people”. As the name suggests, fatal familial insomnia is a genetic condition. (FFI and the others listed are also prion diseases—the prion just emerges on its own without a source prion and no part of the disease is contagious. This is an interesting trait of prions that could not happen with, say, a disease caused by a virus.)
True! I could have talked about scrapie more in this article and didn’t for two reasons-
First, because I looked at some similar transmission tests and it seems to be even less able to convert human PrP.
Second, because as you mention, it’s been around for centuries—if it was going to have spilled over, it probably would have happened by now. CWD, meanwhile, is only a few decades old and has only spread a lot recently- it has more room to explore, so to speak, and some of its possible nearby mutations have never existed around humans before but might now.
As I say in the piece, I think the risk from CWD is in fact low—but this line of reasoning is why human-disease epidemiologists tend to be more concerned about emerging animal diseases than animal diseases that have been around and stable for ages.
Can someone catch FFI from coming into contact with the neural tissues of a patient with FFI?
I suspect it’s possible that FFI genes cause the patient’s body to create prions, but can those prions lead to illness in a person without the FFI gene? If yes, then FFI would still be “infectious” in some sense, I suppose.
Possibly if by “come in contact” we mean like ingesting or injecting or something. That’s the going theory for how the Kuru epidemic started—consumption of the brain of a person with sporadic (randomly-naturally-occuring) CJD. Fortunately cannibalism isn’t too common so this isn’t a usual means of transmission. I think if anything less intensive (say, skin or saliva contact) made CJD transmissible, we would know by now. See also brain contact with contaminated materials e.g. iatrogenic CJD, or Alzheimers which I mention briefly in this piece.
Yep! That’s how it works. Real brutal.
I was thinking of iatrogenic transmissions, yeah (and prions have been a long term psychological fear of mine, too...so I perhaps crawled too much publicly available information about prions to be a normal person)
I wonder if there are any instances of FFI transmitted through the iatrogenic pathway, and whether it is possible to be distinguished from the typical CJD, and whether iatrogenic prions could become a significant issue for healthcare (more instances of prion diseases due to aging population could possibly mean more contaminated medical equipments, and the possible popularisation of brain-computer interface might give us some problems too) given the difficulty of sterilising prions.
Maybe the sample size is too small for us to know.