5 ms·

I remember that in the 90s, when "mad cow disease" was dominating the headlines, it was predicted that there would be an exponential increase in cases, decades

I remember that in the 90s, when "mad cow disease" was dominating the headlines, it was predicted that there would be an exponential increase in cases, decades down the line. The same point about prions being virtually indestructible was being made, the same concerns about surgical equipment and blood donations were raised. Suffice it to say, the prion disaster did not materialize, so I'm skeptical about the same story being repeated almost verbatim today. My guess is that prions aren't all that contagious after all, especially after basic food preparation measures.

ipython 6y ago
The concerns about blood donations continue to this day. A few years ago I went to a blood bank event not even thinking about vCJD and was turned away because I happened to live in Europe for more than 6 months in the early 90s. It is a bit unnerving to know you may or may not have a disease that there is no test for, and symptoms may not appear until decades later.
- 813594 6y ago
  You might want to check again to see if you’re eligible now. They ended some of these restrictions on blood donation in the summer of 2020.
  - ipython 6y ago
    Thanks! It appears that the new restrictions no longer apply to me. I’ll be off to give blood later this month.
- incrudible 6y ago
  ...out of "an abundance of caution". > It is a bit unnerving to know you may or may not have a disease that there is no test for, and symptoms may not appear until decades later. That's true for many neurodegenerative diseases. If that's unnerving to you, better stay away from WebMD...
xenadu02 6y ago
We have no idea if US Beef is infected. The USDA prohibits anyone from testing their cows and ended their spot-testing program (which was a joke). So unlike Europe we never reckoned with the problem and don't know if it is currently spreading. For human exposure we would not yet be far enough along to know if the US Beef supply either is or was contaminated. Personally I have basically stopped eating beef for this reason.
- whatshisface 6y ago
  >The USDA prohibits anyone from testing their cows Huh? Why would they prohibit testing?
  - pm90 6y ago
    Because businesses don’t want to bear the loss (financial and likely reputational) of finding out that their beef contains prions.
    - whatshisface 6y ago
      Thereby combining all of the potential isolated, individually bad disasters into one enormous fully-correlated watershed moment when all companies are simultaneously found to be selling prion-containing beef...
  - mannerheim 6y ago
    The USDA does test a sample of cows, but prohibits companies from doing testing on their own cows probably because the tests would likely be inaccurate and provide an unwarranted impression of safety: > NOT A FOOD SAFETY TEST > BSE tests are not conducted on cuts of meat, but involve taking samples from the brain of a dead animal to see if the infectious agent is present. We know that the earliest point at which current tests can accurately detect BSE is 2-to-3 months before the animal begins to show symptoms. The time between initial infection and the appearance of symptoms is about 5 years. Since most cattle that go to slaughter in the United States are both young and clinically normal, testing all slaughter cattle for BSE might offer misleading assurances of safety to the public. > ... > Why doesn't USDA test every animal at slaughter? > There is currently no test to detect the disease in a live animal. BSE is confirmed by taking samples from the brain of an animal and testing to see if the infectious agent - the abnormal form of the prion protein - is present. The earliest point at which current tests can accurately detect BSE is 2 to 3 months before the animal begins to show symptoms, and the time between initial infection and the appearance of symptoms is about 5 years. Therefore, there is a long period of time during which current tests would not be able to detect the disease in an infected animal. > Since most cattle are slaughtered in the United States at a young age, they are in that period where tests would not be able to detect the disease if present. Testing all slaughter cattle for BSE could produce an exceedingly high rate of false negative test results and offer misleading assurances of the presence or absence of disease. > Simply put, the most effective way to detect BSE is not to test all animals, which could lead to false security, but to test those animals most likely to have the disease, which is the basis of USDA's current program. The ban might not be warranted (I don't believe it is myself), but it is important to be aware that testing for BSE may not be accurate at the time most cows are slaughtered. https://www.usda.gov/topics/animals/bse-surveillance-information-center https://www.usda.gov/topics/animals/bse-surveillance-informa...
mannerheim 6y ago
It isn't really possible to prepare beef in a way to eliminate prions; you have to just make sure the beef you're preparing doesn't have them.
- incrudible 6y ago
  I'm aware that prions are hard to destroy, but that's a different question as to whether they are contagious. A lot of contaminated beef did enter the food chain, yet the expected surge in vCJD did not occur. I would expect cooking to have some impact here, but that's just a guess.
hajile 6y ago
Who knows. I'll give you an interesting thought. There is NO single, conclusive test for Alzheimer's disease. The symptoms are almost identical to CJD (human mad cow) with the biggest differentiator being time from diagnosis to death. Even Amyloid-beta plaque buildup is often (though not always) noted in CJD patients [0][2]. Likewise the other Alzheimer's marker tau protein is also elevated in CJD patients [3]. I'd note that we don't actually know that CJD must progress over 1-2 years rather than a decade -- it is an observational assumption. Between 15-30% of Alzheimer's diagnosed patients also don't have the normal Alzheimer's brain symptom (presumably amyloid buildup) either. Alzheimer's as cause of death was 17.6% in 2000, but is now 37.3% in 2020.[1] Because CJD is defined as killing quickly, it isn't even checked for in such cases (a kind of self-fulfilling prophecy if the diagnosis criteria aren't actually accurate). It doesn't help that cleanup of a contaminated area is time consuming and costly (not to mention potential negative press and panic). This isn't a new idea, but perhaps those fears were somewhat true, but have been buried under our lack of knowledge of protein diseases. [0] https://pubmed.ncbi.nlm.nih.gov/3092727/ https://pubmed.ncbi.nlm.nih.gov/3092727/ [1] https://alz-journals.onlinelibrary.wiley.com/doi/full/10.1002/alz.12068 https://alz-journals.onlinelibrary.wiley.com/doi/full/10.100... [2] https://pubmed.ncbi.nlm.nih.gov/12891683/ https://pubmed.ncbi.nlm.nih.gov/12891683/ [3] https://pubmed.ncbi.nlm.nih.gov/20881758/ https://pubmed.ncbi.nlm.nih.gov/20881758/
- incrudible 6y ago
  > The symptoms are almost identical to CJD (human mad cow) with the biggest differentiator being time from diagnosis to death. Ordinary CJD has a much lower median age of death (68 years) than Alzheimer's (88 years), but vCJD (the form that is believed to be caused by contaminated food) has a median age of death of only 28 years. https://en.wikipedia.org/wiki/Creutzfeldt%E2%80%93Jakob_disease#Classification https://en.wikipedia.org/wiki/Creutzfeldt%E2%80%93Jakob_dise... A surge in young or middle-aged dementia cases would likely not have fallen under the radar. > Between 15-30% of Alzheimer's diagnosed patients also don't have the normal Alzheimer's brain symptom (presumably amyloid buildup) either. Alzheimer's as cause of death was 17.6% in 2000, but is now 37.3% in 2020.[1] You have mistaken the rate of deaths (per 100,000) for the percentage. When judging this increase, one must consider that in the same timeframe, the mean age of the population has risen by 10% and life expectancy increased by more than two years.

ipython 6y ago

The concerns about blood donations continue to this day. A few years ago I went to a blood bank event not even thinking about vCJD and was turned away because I happened to live in Europe for more than 6 months in the early 90s. It is a bit unnerving to know you may or may not have a disease that there is no test for, and symptoms may not appear until decades later.

813594 6y ago
You might want to check again to see if you’re eligible now. They ended some of these restrictions on blood donation in the summer of 2020.
- ipython 6y ago
  Thanks! It appears that the new restrictions no longer apply to me. I’ll be off to give blood later this month.
incrudible 6y ago
...out of "an abundance of caution". > It is a bit unnerving to know you may or may not have a disease that there is no test for, and symptoms may not appear until decades later. That's true for many neurodegenerative diseases. If that's unnerving to you, better stay away from WebMD...

xenadu02 6y ago

We have no idea if US Beef is infected. The USDA prohibits anyone from testing their cows and ended their spot-testing program (which was a joke). So unlike Europe we never reckoned with the problem and don't know if it is currently spreading. For human exposure we would not yet be far enough along to know if the US Beef supply either is or was contaminated. Personally I have basically stopped eating beef for this reason.

whatshisface 6y ago
>The USDA prohibits anyone from testing their cows Huh? Why would they prohibit testing?
- pm90 6y ago
  Because businesses don’t want to bear the loss (financial and likely reputational) of finding out that their beef contains prions.
  - whatshisface 6y ago
    Thereby combining all of the potential isolated, individually bad disasters into one enormous fully-correlated watershed moment when all companies are simultaneously found to be selling prion-containing beef...
- mannerheim 6y ago
  The USDA does test a sample of cows, but prohibits companies from doing testing on their own cows probably because the tests would likely be inaccurate and provide an unwarranted impression of safety: > NOT A FOOD SAFETY TEST > BSE tests are not conducted on cuts of meat, but involve taking samples from the brain of a dead animal to see if the infectious agent is present. We know that the earliest point at which current tests can accurately detect BSE is 2-to-3 months before the animal begins to show symptoms. The time between initial infection and the appearance of symptoms is about 5 years. Since most cattle that go to slaughter in the United States are both young and clinically normal, testing all slaughter cattle for BSE might offer misleading assurances of safety to the public. > ... > Why doesn't USDA test every animal at slaughter? > There is currently no test to detect the disease in a live animal. BSE is confirmed by taking samples from the brain of an animal and testing to see if the infectious agent - the abnormal form of the prion protein - is present. The earliest point at which current tests can accurately detect BSE is 2 to 3 months before the animal begins to show symptoms, and the time between initial infection and the appearance of symptoms is about 5 years. Therefore, there is a long period of time during which current tests would not be able to detect the disease in an infected animal. > Since most cattle are slaughtered in the United States at a young age, they are in that period where tests would not be able to detect the disease if present. Testing all slaughter cattle for BSE could produce an exceedingly high rate of false negative test results and offer misleading assurances of the presence or absence of disease. > Simply put, the most effective way to detect BSE is not to test all animals, which could lead to false security, but to test those animals most likely to have the disease, which is the basis of USDA's current program. The ban might not be warranted (I don't believe it is myself), but it is important to be aware that testing for BSE may not be accurate at the time most cows are slaughtered. https://www.usda.gov/topics/animals/bse-surveillance-information-center https://www.usda.gov/topics/animals/bse-surveillance-informa...

mannerheim 6y ago

It isn't really possible to prepare beef in a way to eliminate prions; you have to just make sure the beef you're preparing doesn't have them.

incrudible 6y ago
I'm aware that prions are hard to destroy, but that's a different question as to whether they are contagious. A lot of contaminated beef did enter the food chain, yet the expected surge in vCJD did not occur. I would expect cooking to have some impact here, but that's just a guess.

hajile 6y ago

Who knows. I'll give you an interesting thought. There is NO single, conclusive test for Alzheimer's disease. The symptoms are almost identical to CJD (human mad cow) with the biggest differentiator being time from diagnosis to death. Even Amyloid-beta plaque buildup is often (though not always) noted in CJD patients [0][2]. Likewise the other Alzheimer's marker tau protein is also elevated in CJD patients [3]. I'd note that we don't actually know that CJD must progress over 1-2 years rather than a decade -- it is an observational assumption. Between 15-30% of Alzheimer's diagnosed patients also don't have the normal Alzheimer's brain symptom (presumably amyloid buildup) either. Alzheimer's as cause of death was 17.6% in 2000, but is now 37.3% in 2020.[1] Because CJD is defined as killing quickly, it isn't even checked for in such cases (a kind of self-fulfilling prophecy if the diagnosis criteria aren't actually accurate). It doesn't help that cleanup of a contaminated area is time consuming and costly (not to mention potential negative press and panic). This isn't a new idea, but perhaps those fears were somewhat true, but have been buried under our lack of knowledge of protein diseases. [0] https://pubmed.ncbi.nlm.nih.gov/3092727/ https://pubmed.ncbi.nlm.nih.gov/3092727/ [1] https://alz-journals.onlinelibrary.wiley.com/doi/full/10.1002/alz.12068 https://alz-journals.onlinelibrary.wiley.com/doi/full/10.100... [2] https://pubmed.ncbi.nlm.nih.gov/12891683/ https://pubmed.ncbi.nlm.nih.gov/12891683/ [3] https://pubmed.ncbi.nlm.nih.gov/20881758/ https://pubmed.ncbi.nlm.nih.gov/20881758/

incrudible 6y ago
> The symptoms are almost identical to CJD (human mad cow) with the biggest differentiator being time from diagnosis to death. Ordinary CJD has a much lower median age of death (68 years) than Alzheimer's (88 years), but vCJD (the form that is believed to be caused by contaminated food) has a median age of death of only 28 years. https://en.wikipedia.org/wiki/Creutzfeldt%E2%80%93Jakob_disease#Classification https://en.wikipedia.org/wiki/Creutzfeldt%E2%80%93Jakob_dise... A surge in young or middle-aged dementia cases would likely not have fallen under the radar. > Between 15-30% of Alzheimer's diagnosed patients also don't have the normal Alzheimer's brain symptom (presumably amyloid buildup) either. Alzheimer's as cause of death was 17.6% in 2000, but is now 37.3% in 2020.[1] You have mistaken the rate of deaths (per 100,000) for the percentage. When judging this increase, one must consider that in the same timeframe, the mean age of the population has risen by 10% and life expectancy increased by more than two years.