Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

CJD, Kuru and Alzheimers connected?

  1. Jun 30, 2005 #1
    Does anyone else know or believe that there is a strong link between CJD, Kuru and Alzheimers? Kuru is directly linked to cannibalism and is pretty much the same thing as CJD. CJD is often misdiagnosed as Alzheimers and in some cases it is believed that it is linked to eating beef from a cow infected with BSE (mad cow disease). BSE is also linked to cannibalism among cows (cow feed from rendering plants that uses/used parts or all of other dead cows)

    -Alzheimers and elderly dementia (which is not considered a "normal" part of the aging process) have nearly the same symptoms as CJD. Kuru also has symptoms that are like CJD--

    -does anyone know about this??

    *by the way, as of today a US case of mad cow disease has been reported in texas
     
  2. jcsd
  3. Jun 30, 2005 #2

    Evo

    User Avatar

    Staff: Mentor

    First a link to the Mad Cow in Texas, it wasn't a human that was infected, no signs of it being in the food supply, which is good.

    Second BSE-Positive Cow Identified in the United States

    On June 24, 2005, the U.S. Department of Agriculture announced receipt of final results from The Veterinary Laboratories Agency in Weybridge, England, confirming BSE in a cow that had conflicting test results in 2004. No parts of the animal entered the human and animal food supply. As a result of this BSE positive animal, the USDA plans to develop a new laboratory testing protocol to evaluate future inconclusive BSE screening test results.

    http://www.cdc.gov/ncidod/dvrd/bse/bse_cow_june_2005.htm

    A link to an article on CJD & Alzheimer's, but it's 5 years old.

    http://news.bbc.co.uk/1/hi/health/892819.stm
     
  4. Jun 30, 2005 #3
    Hadn't heard about the Alzheimer's link, thanks.

    If I understood the Texas cow case - the 12 year old cow was a breed that is used to make feed for other cattle.

    That it came from a herd that had been exposed to the prions a decade ago (we can assume this because the cow had the disease), raises the possibility that this herd has (and had) additional infected cows. The sick one was identified because it was a downer (trouble standing.) In other words, the herd was not being screened preventatively, but rather when a sick cow with BSE symptoms presented, they tested for the disease (and found it.) The cow probably contracted the disease early in its life - before (1995?) regulations prohibited brain and spinal cord frm entering the cow food supply.

    This breed of cow is used to feed other cows, including beef cattle, although brain/spinal cord is no longer allowed in the feed (I wonder how careful the butchers are.).
     
  5. Jun 30, 2005 #4

    selfAdjoint

    User Avatar
    Staff Emeritus
    Gold Member
    Dearly Missed

    I thought the FDA said after the British experience that US cattle were not being fed on bodies of other cattle. Were they lying?
     
  6. Jun 30, 2005 #5
    I believe they changed the rules in 1995, to proibit brain and spinal cord from being fed to cattle. In response to the UK's outbreak of CJD.

    This Texan cow was 12 years old, and could have received brain/spinal cord in its feed, as a calf.

    I believe other parts of the cow are still considered safe for cow as well as human (obviously) consumption. But given how much fecal contamination ends up in beef at the supermarket (every sample our microbiology class has ever tested has been positive for fecal contamination) it wouldn't surprise me if the odd bit of CNS occasionally slips by the butcher and winds up in the cattle feed.
     
  7. Jun 30, 2005 #6

    Evo

    User Avatar

    Staff: Mentor

    I thought they had stopped including beef by products in cattle feed, but it appears it is still a problem. See article.

    Loopholes in Ban on Cattle Remains in Feed
    By The Associated Press

    Published: Jun 17, 2005 2:29 PM EST

    http://ap.lancasteronline.com/4/mad_cow_loopholes
     
  8. Jun 30, 2005 #7
    I think that the FDA decided to stop using the brain and spinal cord of cattle for cattle feed in 1997--however there has been known violations by many companies..

    --another concern I have is the use of elk, deer, cat, ect. that are from rendering plants. These animals have known prion 'viruses' just like BSE, so do mink, sheep (scrabies) and i think goats do as well.. these animals (as far as I know) are not banned by the FDA to be used by rendering plants that produce proteins, ect. to be used in all types of animal feed
     
  9. Jun 30, 2005 #8
    just as a quick note on the link between CJD and Alzheimers.

    Both diseases involve the formation of amyloid in the brain. With CJD it is the protein PrP, which the function of is still unknown. In Alzheimers it is APP. Basically, amyloid is a fibrous protein structure that forms usually by aggregating the proteins into long filaments which have a specific structure (for example , the tertiary structure is Beta-sheet). Yet they are not the same diseases. I don't think it is known yet whether these structures forming is the cause of the disease or just a side effect of some other phenomenon. Either way, once these aggregates form, they cause massive degeneration of the brain.

    The PrP protein is called a prion because it is infectious, kind of like a virus. APP is not infectious, so it is not a prion although they have the similar affects on the brain and a very similar pathologies(I'm not sure if that is the right word).
    The idea is if you eat an animal (only mammals have PrP) who is infected, the PrP prion(the amyloid form) somehow travels eventually to your brain. You have to eat infected tissue and as of now I think only the brain and maybe the spleen will contain any. What is hypothesized to happen is that the PrP prion from say the cow gets into your brain and then converts all of your PrP protein into prion. So its not just that the prion itself is harmful, but that it turns your native protein into amyloid. Interestingly, there are some species barriers, for example, the sheep version can only infect humans after it has been in cows. In the United States, I think our biggest worry should be with our deer populations which have very high levels of this prion disease(I forget the name) and noone really knows why they are getting it at such high rates and I don't know if any hunters know of this danger.

    Kuru is thought to be the same as CJD. CJD is known mostly from spontaneous cases that arise while kuru is from eating brains. There is a book about this if you are really interested in it called, Deadly feasts by Richard Rhodes.

    I hope that answers some of your questions. I used to work in a lab working on prion proteins so I apologize if I went on a tangent.
     
    Last edited: Jun 30, 2005
  10. Jun 30, 2005 #9
    Plus the cattle that consumed the animal feed prior to 1997 and all of thier offspring may also be infected and they may still (and obviously are) still alive in the US and may be wiating to be used for human consumption--plus I do not know how many generations the prions can be genetically passed on

    -the government does conduct testing for BSE on selected or maybe random cattle, however they do not test the spinal cord and brain of every cow that is processed through the slaughter house

    -another thing,,,what about how clean the rendering plant, animal feed plants and the slaughter houses are?--Prions are known to be pretty resistant, and I think I heard of some CJD cases that were linked to a rendering plant that stopped using spinal cord/brain of cattle, but the machines in the plant had been cleaned but not fully sanitized.
     
  11. Jun 30, 2005 #10

    Evo

    User Avatar

    Staff: Mentor

    That was very helpful detta, thank you!
     
  12. Jun 30, 2005 #11
    From what I know there are at least 2 types of CJD. One that is sporadic (sCJD) and the other that is genetic or hereditary (I think it's hCJD or gCJD) The majority of CJD cases are not sCJD
     
  13. Jun 30, 2005 #12

    Evo

    User Avatar

    Staff: Mentor

    The two types are CJD and vCJD, it is the vCJD that is linked to eating infected beef.
     
  14. Jun 30, 2005 #13

    Moonbear

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    It's not a genetic disease, but whether a cow could pass it to a calf, I don't know. Usually if a cow is tested positive, I think they do track all farms that cow has been on and all other cattle, including offspring, that have been in contact with that cow. The cases being identified in the US are still cattle old enough to have been around before restrictions on feed were put in place. It doesn't mean there aren't unscrupulous farmers who will try to cheat the system, just like in any line of work, but that's not the majority. The majority know that it's not worth the risk of losing their entire herd.

    That's a good point. I haven't heard of such cases, so don't know if that's true or not, but even sterilization by autoclaving doesn't always destroy all prions (this is why it's a big concern when a patient is discovered to have CJD after surgical instruments were used on other patients; even if they are properly sterilized, there remains a risk of spreading the prions apparently). I don't know how much of a risk that would pose or what has been done to sterilize the facilities.

    detta, thanks for a very thorough response!
     
  15. Jul 1, 2005 #14

    DocToxyn

    User Avatar
    Science Advisor

    Detta, you raise some great points and thanks for the info on prions.
    Just to clarify, the word pathology can be used appropriately in that case but probably only on a certain scale. If one is speaking to the protein alterations and termed it a pathology of protein formation/folding that would probably be correct. However, as far as brain tissue pathology, when referencing the lesions associated with AD vs. CJD, I'm pretty sure there is a difference. The spongiform encephalopathy that is associated with CJD results in holes being formed across most of the brain, I don't think it is specific to any brain region or cell type. With AD the lesion is more specific and typically associated with the hippocampus and cholinergic regions of the brain. The presentation of the diseases may also differ since the more global aspects of CJD lesions can target motor function as well as cognition.
     
  16. Jul 1, 2005 #15
    I just read that a case of vCJD was confired in Dublin and the man was a previous blood donor (apparently the disease / virus can be spread through blood transfusion as well)

    http://www.rte.ie/news/2005/0630/cjd.html
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: CJD, Kuru and Alzheimers connected?
Loading...