Could Prions Cause “Mad Dog” Disease?

September 5, 2008 at 12:00 am 4 comments

From Today’s Scientific American 60-Second Science Podcast an interesting — and rather chilling – report on prion diseases.

Prions are abnormally shaped proteins that spread disease by causing normal proteins to mis-fold into their abnormal shape.  Genetic material like DNA or RNA is not involved in the creation or spread of prions. Prion diseases affect the brains and central nervous systems of many mammals — including humans. And though we humans can catch mad cow disease from eating infected beef; prions were believed jump the species barrier only rarely.

As reported in SciAm:

A study published in the September 4th issue of the journal Cell investigates that issue. Scientists from Texas, Spain and Chile took normal hamster proteins and mixed them with misfolded mouse ones. And the mouse prions were able to change the hamster proteins into a new kind of prion that infected both healthy hamsters and mice. The test tube is obviously an unnatural situation, but it shows that prions can leap the species barrier without the aid of any other infectious agent. Scientists hope to learn more about how this process works so they can keep prions in their place-away from humans.

Back in the 90’s, thousands of cattle in Great Britain collapsed from a mysterious malady now known as mad cow disease. And at that time experts assured us that people couldn’t get the disease from eating beef.  The species barrier – “a kind of biological Hadrian’s wall” — would protect human carnivores from harm.

As reported in the New York Times back in June, 2003:

So much for scientific hubris. After young people began dying in 1996 from a new variant of Creutzfeldt-Jakob disease, a rare malady thought to occur only in older people, the experts were forced to admit they were wrong.

The people had died because they ate meat from infected cows. A species barrier had crumbled.

Prion diseases, (e.g. BSE, FSE, scrapie and other spongioform encephalopathies) are poorly understood though they occur in most mammals. Scientists have known for some time that prion diseases can be spread when animals cannibalize each other (i.e. eat the remains of others of their own species).  Prion species are problematic for several reasons:

  • They often incubate for long periods of time before they cause detectable symptoms.
  • Symptoms of prion diseases can be highly variable, both between individual animals and between species.
  • Some prion diseases can be transmitted from one species to another – but others appear not to cross the species barrier.
  • Some animals may act as unaffected carriers of these diseases, transmitting them without being affected themselves.
  • Because of the long incubation time common in prion diseases, some species may pass them on before being affected themselves.
  • In some cases an intermediate species may act as a host to a subclinical form of a prion infection and then act to transport it between two other species.
  • Prions are astonishingly resistant to disinfectants. Bleach, ultraviolet radiation, heat and other common sterilizing agents have little or no effect on them.
  • Some evidence indicates that prions can be inherited – passed from parent to offspring before birth.

Research on species barriers and prion diseases is fraught with enigmas, dead-ends, contradictions and confusion.

One of the main jobs our cells carry out is folding up proteins, the workhorse molecules of our bodies. Each protein molecule can be folded in several different ways before it finds its final shape and function. Mistakes can occur during folding but mis-folded proteins are usually found and disposed of by enzymes.

Mis-folded prion proteins are resistant to discovery and/or disposal by enzymes (or stomach acid). The prions remain in the body and may cause damage – like the characteristic spongelike holes in brain cells found in BSE and CJD.

Humans can suffer from prion diseases.  Can dogs?

The answer so far has been “no”, but it seems more accurate now to say “we don’t know.”

No evidence of a canine prion disease has been discovered yet (though a feline version, FSE, exists) – but there is currently no way to test for these diseases in live animals. Brain and spinal cord biopsies are the only diagnostic tool currently available so it is possible that a canine prion disease may exist, but have detectable symptoms that are remarkably different from those seen in cows and humans. 

If this is the case, such a disease could be misdiagnosed for some period of time before it is discovered.

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4 Comments Add your own

  • 1. Audie's Gramma  |  September 5, 2008 at 3:56 am

    We’re exercising caution about ruminant nervous tissue around here.

    Thus far CWD hasn’t hit the deer herd around here, but we’re processing our own deer now, and discarding the head and spinal tissues uncut. It feels very wrong to waste all this stuff the dogs would love.

    As primarily home-prepped raw feeders, our dogs are probably at less risk than those that eat kibble, with meat ingredients from wherever. Prions aren’t killed by heat. Working with whole foods from known, local sources is our best bet.

    Another tack would be to avoid ruminant ingredients altogether, sticking with poultry, fish, swine, eggs. Even horsemeat.

  • 2. Terry S. Singeltary Sr.  |  September 5, 2008 at 3:02 pm

    HOUND STUDY

    AS implied in the Inset 25 we must not _ASSUME_ that transmission of BSE to other species will invariably present pathology typical of a scrapie-like disease.

    snip…

    http://www.bseinquiry.gov.uk/files/yb/1991/01/04004001.pdf

    2005 DEFRA Department for Environment, Food & Rural Affairs

    Area 307, London, SW1P 4PQ Telephone: 0207 904 6000 Direct line: 0207 904 6287 E-mail: h.mcdonagh.defra.gsi.gov.uk

    GTN: FAX:

    Mr T S Singeltary P.O. Box 42 Bacliff Texas USA 77518

    21 November 2001

    Dear Mr Singeltary

    TSE IN HOUNDS

    Thank you for e-mail regarding the hounds survey. I am sorry for the long delay in responding.

    As you note, the hound survey remains unpublished. However the Spongiform Encephalopathy Advisory Committee (SEAC), the UK Government’s independent Advisory Committee on all aspects related to BSE-like disease, gave the hound study detailed consideration at their meeting in January 1994. As a summary of this meeting published in the BSE inquiry noted, the Committee were clearly concerned about the work that had been carried out, concluding that there had clearly been problems with it, particularly the control on the histology, and that it was more or less inconclusive. However was agreed that there should be a re-evaluation of the pathological material in the study.

    Later, at their meeting in June 95, The Committee re-evaluated the hound study to see if any useful results could be gained from it. The Chairman concluded that there were varying opinions within the Committee on further work. It did not suggest any further transmission studies and thought that the lack of clinical data was a major weakness.

    Overall, it is clear that SEAC had major concerns about the survey as conducted. As a result it is likely that the authors felt that it would not stand up to r~eer review and hence it was never published. As noted above, and in the detailed minutes of the SEAC meeting in June 95, SEAC considered whether additional work should be performed to examine dogs for evidence of TSE infection. Although the Committee had mixed views about the merits of conducting further work, the Chairman noted that when the Southwood Committee made their recommendation to complete an assessment of possible spongiform disease in dogs, no TSEs had been identified in other species and hence dogs were perceived as a high risk population and worthy of study. However subsequent to the original recommendation, made in 1990, a number of other species had been identified with TSE ( e.g. cats) so a study in hounds was less

    critical. For more details see- http://www.bseinquiry, gov.uk/files/yb/1995/06/21005001 .pdf

    As this study remains unpublished, my understanding is that the ownership of the data essentially remains with the original researchers. Thus unfortunately, I am unable to help with your request to supply information on the hound survey directly. My only suggestion is that you contact one of the researchers originally involved in the project, such as Gerald Wells. He can be contacted at the following address.

    Dr Gerald Wells, Veterinary Laboratories Agency, New Haw, Addlestone, Surrey, KT 15 3NB, UK

    You may also wish to be aware that since November 1994 all suspected cases of spongiform encephalopathy in animals and poultry were made notifiable. Hence since that date there has been a requirement for vets to report any suspect SE in dogs for further investigation. To date there has never been positive identification of a TSE in a dog.

    I hope this is helpful

    Yours sincerely 4

    HUGH MCDONAGH BSE CORRESPONDENCE SECTION

    IN CONFIDENCE

    CONCEPT NOT FOR FURTHER STUDY OF MATERIAL OBTAINED IN A SURVEY OF HOUNDS FOR EVIDENCE OF A SCRAPIE-LIKE SPONGIFORM ENCEPHALOPATHY (SE)

    snip…

    b) Fibrillar material closely similar to SAF, found in BSE/Scrapie, was observed in 19 (4.3%) cases, all of which were hounds > 7 years of age. 14/19 of these suspected SAF results correlated with cases in the unresolveable histopathological category.

    snip…

    The following proposals address the hypothesis that the hound survey observations represent a PrP related or scrapie-like disease of dogs in which the pathological response, and possible the spread of infectivity, is neuroanatomically localized. By inference this could also mean that the disorder is clinically silent and non-progressive.

    http://www.bseinquiry.gov.uk/files/yb/1995/02/09001001.pdf

    http://www.mad-cow.org/00/aug00_late_news.html#ggg

    http://www.kxnet.com/getForumPost.asp?ArticleId=113652

    http://www.keeneequinox.com/home/index.cfm?event=displayArticleComments&ustory_id=4d8de1c2-fa09-42dc-958a-7e94e16e22db

    PET FOODS MAD CATS AND MAD DOGS BSE/TSEs

    worse still, there is serious risk the media could get to hear of such a meeting…

    snip…

    Crushed heads (which inevitably involve brain and spinal cord material) are used to a limited extent but will also form one of the constituent raw materials of meat and bone meal, which is used extensively in pet food manufacturer…

    http://www.bseinquiry.gov.uk/files/yb/1989/03/17004001.pdf

    2. The Parliamentary Secretary said that he was concerned about the possibility that countries in which BSE had not yet been detected could be exporting raw meat materials (in particular crushed heads) contaminated with the disease to the UK for use in petfood manufacture…

    snip…

    YOU explained that imported crushed heads were extensively used in the petfood industry…

    http://www.bseinquiry.gov.uk/files/yb/1989/04/14001001.pdf

    In particular I do not believe one can say that the levels of the scrapie agent in pet food are so low that domestic animals are not exposed…

    http://www.bseinquiry.gov.uk/files/yb/1989/04/24003001.pdf

    40. When Sir Richard Southwood gave oral evidence to the Agriculture Select Committee, he said:

    ‘The case of the cat is the first case of spongiform encephalopathy ever in a cat. Well, it appears to be – but if poor moggie got a bit of the staggers, you took it along to the vet and said it was not very happy, it would be put to sleep in the past and no one would have paid £300 to have a post mortem undertaken. So it is just possible that these were occurring before and were in fact caught from moggie being fed scrapie offal from sheep. I cannot say.’[46]

    NEXT, ask yourself how many cats and dogs have ever been tested for TSE in the USA ???

    DOGS are not tested for TSE. THEY ARE RENDERED UP INTO LITTLE PELLETS, WITH ALL THE OTHER ROAD KILL, and fed back to animals for human and animal consumption. it’s an endless cycle of greed. …

  • 3. Dov Henis  |  September 6, 2008 at 2:37 am

    Neurodegenerative Diseases, Prions, And Life Genesis

    A. Involvement of misfolded proteins

    http://researchnews.osu.edu/archive/targettau.htm

    – Alzheimer’s disease is the most common form of dementia among older people. It initially involves the parts of the brain that control thought, memory and language

    – In other neurodegenerative diseases, the deposition of aggregates enriched in certain tau isoforms has been reported. When misfolded this otherwise very soluble protein can form extremely insoluble aggregates that contribute to a number of neurodegenerative diseases.

    B. Prions, Normal and Pathogenic.

    http://blog.360.yahoo.com/blog-P81pQcU1dLBbHgtjQjxG_Q–?cq=1&p=125

    and

    http://www.the-scientist.com/community/posts/list/122.page#348

    – Infectious prions And misfolded proteins. The infectious isoform of normal PrPC, known as PrPSc, is able to convert normal PrPC proteins into the infectious isoform by changing their conformation.

    – “Scientists are learning more about the protein behind mad cow and Creutzfeldt-Jakob disease, including how to interfere with the proteins’ production in the brains of mice. ”

    – “It’s also a mystery how prions replicate — they seem to do it without DNA — and they are difficult to kill.”

    – But, then, it’s also a mystery how at Genesis RNA-related oligomers replicated without DNA!…

    C. Again, a phenomenological relationship…

    IMO there is a definite, even if yet vaguely understood, relationship between CJ and Life Genesis phenomena parallel to the phenomenological relationship between black-holes and biosphere phenomena.

    Black-holes and Biosphere(s?) are both phenomena of constrained energy pockets within a universe of an expanding energy matrix.

    CJ and Life Genesis are both phenomena of serendipitous occurrence of ‘favourably-directed’ energy potential:

    – in the case of life genesis, between incoming sun’s radiation and RNA-related oligomeric configuration, and

    – in degenerating proteins replication, between specific protein-forming-folding-enzymes and enzymes-protein complexes.

    musing,

    Dov Henis

    http://blog.360.yahoo.com/blog-P81pQcU1dLBbHgtjQjxG_Q–?cq=1

    ==========================

    Life Manifest

    Recapitulation of some earlier notes on
    The Drive, Nature And Purpose Of Life: Scientific Comprehension

    http://www.physforum.com/index.php?showtopic=14988&st=195&#entry330517

    A. Uniqueness Of science among human artifacts

    ALL aspects of our culture are, of course, anthropoartifacts, including science. Yet among those artifacts science has a distinct uniqueness for us.

    During the recent several centuries in the course of human history humans have been developing science at an accelerating rate as a provider of convincing, ever closer approaching, approximate models of the real world.

    B. The drive and nature of life

    The drive of life and of its evolution is to enhance the functionality and survivability of the genes, in order to maintain and enhance Earth-biosphere’s temporary constrained energy storage and to maintain it BIO as long as possible.

    It is the genes, life’s prime strata organisms, that evolve, and the evolution of genomes, the 2nd stratum of life, and of the 3rd life stratum cellular organisms, is an interenhancing consequence of their genes’ evolution.

    C. The nature of life

    Earth Life: 1. a format of temporarily constrained energy, retained in temporary constrained genetic energy packages in forms of genes, genomes and organisms 2. a real virtual affair that pops in and out of existence in its matrix, which is the energy constrained in Earth’s biosphere.

    Earth organism: a temporary self-replicable constrained-energy genetic system that supports and maintains Earth’s biosphere by maintenance of genes.

    Gene: a primal Earth’s organism. (1st stratum organism)

    Genome: a multigenes organism consisting of a cooperative commune of its member genes. (2nd stratum organism)

    Cellular organisms: mono- or multi-celled earth organisms. (3rd stratum organism)

    D. Update of underlying life sciences conception is thus feasible

    – First were independent individual genes, Earth’s primal organisms.

    – Genes aggregated cooperatively into genomes, multigenes organisms, with genomes’ organs.

    – Simultaneously or consequently genomes evolved protective and functional membranes, organs.

    – Then followed cellular organisms, with a variety of outer-cell membrane shapes and
    functionalities.

    This conception is a scientific, NOT TECHNOLOGICAL, life-science innovation.

    It is tomorrow’s comprehension of life and of its evolution.

    IT IS FRAUGHT WITH INTRIGUING DARWINIAN EVOLUTION IMPLICATIONS.

    IT IS FRAUGHT WITH INTRIGUING TECHNOLOGICAL DEVELOPMENTS POTENTIALS.

    E. The purpose of OUR, human, life

    The purpose of OUR life and its promotion is ours to formulate and set. It derives solely from our cognition.

    Suggesting,

    Dov Henis

    http://blog.360.yahoo.com/blog-P81pQcU1dLBbHgtjQjxG_Q–?cq=1

  • 4. flounder9  |  March 26, 2012 at 10:36 am

    well, I said it a decade ago, bbbut nobody believed me…or what they call doggy dementia, aka mad dog disease or mad cow disease in dogs…

    Monday, March 26, 2012

    CANINE SPONGIFORM ENCEPHALOPATHY: A NEW FORM OF ANIMAL PRION DISEASE

    http://caninespongiformencephalopathy.blogspot.com/2012/03/canine-spongiform-encephalopathy-new.html

    kind regards,
    terry

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