Monday, April 10, 2017

Disease-associated prion protein detected in lymphoid tissues from pigs challenged with the agent of chronic wasting disease

Disease-associated prion protein detected in lymphoid tissues from pigs challenged with the agent of chronic wasting disease

Research Project: TRANSMISSION, DIFFERENTIATION, AND PATHOBIOLOGY OF TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHIES

Location: Virus and Prion Research

Title: Disease-associated prion protein detected in lymphoid tissues from pigs challenged with the agent of chronic wasting disease

Author item Moore, Sarah item Kunkle, Robert item Kondru, Naveen item Manne, Sireesha item Smith, Jodi item Kanthasamy, Anumantha item West Greenlee, M item Greenlee, Justin

Submitted to: Prion Publication Type: Abstract Only Publication Acceptance Date: 3/15/2017 Publication Date: N/A Citation: N/A Interpretive Summary:

Technical Abstract: Aims: Chronic wasting disease (CWD) is a naturally-occurring, fatal neurodegenerative disease of cervids. We previously demonstrated that disease-associated prion protein (PrPSc) can be detected in the brain and retina from pigs challenged intracranially or orally with the CWD agent. In that study, neurological signs consistent with prion disease were observed only in one pig: an intracranially challenged pig that was euthanized at 64 months post-challenge. The purpose of this study was to use an antigen-capture immunoassay (EIA) and real-time quaking-induced conversion (QuIC) to determine whether PrPSc is present in lymphoid tissues from pigs challenged with the CWD agent. Methods: At two months of age, crossbred pigs were challenged by the intracranial route (n=20), oral route (n=19), or were left unchallenged (n=9). At approximately 6 months of age, the time at which commercial pigs reach market weight, half of the pigs in each group were culled (6 month challenge groups) were allowed to incubate for up to 73 months post challenge (mpc). The retropharyngeal lymph node (RPLN) was screened for the presence of PrPSc by EIA and immunohistochemistry (IHC). The RPLN, palatine tonsil, and mesenteric lymph node (MLN) from 6-7 pigs per challenge group were also tested using EIA and QuIC. Results: PrPSc was not detected by EIA and IHC in any RPLNs. All tonsils and MLNs were negative by IHC, though the MLN from one pig in the oral 6 months group, 5/6 pigs in the oral 6 months group. Overall, the MLN was positive in 14/19 (74%) of samples examined, the RPLN in 8/18 (44%), and the tonsil in 10/25 (40%). 

Conclusions: This study demonstrates that PrPSc accumulates in lymphoid tissues from pigs challenged intracranially or orally with the CWD agent, and can be detected as early as 4 months after challenge. CWD-infected pigs rarely develop clinical disease and if they do, they do so after a long incubation period. This raises the possibility that CWD-infected pigs could shed prions into their environment long before they develop clinical disease. Furthermore, lymphoid tissues from CWD-infected pigs could present a potential source of CWD infectivity in the animal and human food chains.

https://www.ars.usda.gov/research/publications/publication/?seqNo115=337105

CONFIDENTIAL

EXPERIMENTAL PORCINE SPONGIFORM ENCEPHALOPATHY

While this clearly is a cause for concern we should not jump to the conclusion that this means that pigs will necessarily be infected by bone and meat meal fed by the oral route as is the case with cattle. ...

http://web.archive.org/web/20031026000118/www.bseinquiry.gov.uk/files/yb/1990/08/23004001.pdf

we cannot rule out the possibility that unrecognised subclinical spongiform encephalopathy could be present in British pigs though there is no evidence for this: only with parenteral/implantable pharmaceuticals/devices is the theoretical risk to humans of sufficient concern to consider any action.

http://web.archive.org/web/20030822031154/www.bseinquiry.gov.uk/files/yb/1990/09/10007001.pdf

May I, at the outset, reiterate that we should avoid dissemination of papers relating to this experimental finding to prevent premature release of the information. ...

http://web.archive.org/web/20030822052332/www.bseinquiry.gov.uk/files/yb/1990/09/11005001.pdf

3. It is particularly important that this information is not passed outside the Department, until Ministers have decided how they wish it to be handled. ...

http://web.archive.org/web/20030822052438/www.bseinquiry.gov.uk/files/yb/1990/09/12002001.pdf

But it would be easier for us if pharmaceuticals/devices are not directly mentioned at all. ...

http://web.archive.org/web/20030518170213/www.bseinquiry.gov.uk/files/yb/1990/09/13004001.pdf

Our records show that while some use is made of porcine materials in medicinal products, the only products which would appear to be in a hypothetically ''higher risk'' area are the adrenocorticotrophic hormone for which the source material comes from outside the United Kingdom, namely America China Sweden France and Germany. The products are manufactured by Ferring and Armour. A further product, ''Zenoderm Corium implant'' manufactured by Ethicon, makes use of porcine skin - which is not considered to be a ''high risk'' tissue, but one of its uses is described in the data sheet as ''in dural replacement''. This product is sourced from the United Kingdom.....

http://web.archive.org/web/20030822054419/www.bseinquiry.gov.uk/files/yb/1990/09/21009001.pdf

Porcine prion protein amyloid 

Per Hammarstr€om and Sofie Nystr€om* IFM-Department of Chemistry; Link€oping University; Link€oping, Sweden 

ABSTRACT. Mammalian prions are composed of misfolded aggregated prion protein (PrP) with amyloid-like features. 

Prions are zoonotic disease agents that infect a wide variety of mammalian species including humans. Mammals and by-products thereof which are frequently encountered in daily life are most important for human health. It is established that bovine prions (BSE) can infect humans while there is no such evidence for any other prion susceptible species in the human food chain (sheep, goat, elk, deer) and largely prion resistant species (pig) or susceptible and resistant pets (cat and dogs, respectively). PrPs from these species have been characterized using biochemistry, biophysics and neurobiology. Recently we studied PrPs from several mammals in vitro and found evidence for generic amyloidogenicity as well as cross-seeding fibril formation activity of all PrPs on the human PrP sequence regardless if the original species was resistant or susceptible to prion disease. Porcine PrP amyloidogenicity was among the studied. Experimentally inoculated pigs as well as transgenic mouse lines overexpressing porcine PrP have, in the past, been used to investigate the possibility of prion transmission in pigs. The pig is a species with extraordinarily wide use within human daily life with over a billion pigs harvested for human consumption each year. Here we discuss the possibility that the largely prion disease resistant pig can be a clinically silent carrier of replicating prions. 

KEYWORDS. prion, pig, amyloid fibril, misfolding, transmissibility, seeding, TSE, prion strain, strain adaptation

snip...

What about pigs? In several recent papers which in our view have not received sufficient attention the notion of prion resistant pigs was challenged by generation of transgenic mice with knocked out endogenous PrP and overexpressed PoPrP. Different lines of tgPoPrP mouse were proven to be susceptible to clinical disease triggered by a variety of prion strains, suggesting that the surrogate host species (mouse) and prion strain are more important than what PrP sequence it expresses for neurotoxicity to commence. In more detail, Torres and colleagues experimentally subjected transgenic mouse lines expressing porcine PrP to a number of different TSE isolates.24-26 Their studies demonstrate that prion infection is strain specific when porcine PrP is overexpressed (4x) and used as in vivo substrate. PoTg001 mice inoculated with classical scrapie, regardless of donor genotype, resisted prion disease both at first and second passage (Fig. 3b). On the other hand, Nor98 scrapie (Atypical scrapie) as well as BSE from both cattle and BoTg mouse model resulted in clinical disease in the PoTg001 mice. However, in the first generation, disease progression was slow. Incubation time until death was as long as 600 d and the hit rate was low. This indicates that disease has barely developed by the time the mice reach their natural life span limit which in this study was set to 650 d Already in the second passage the hit rate was 100 % and the incubation time was cut in half (Fig. 3b). No further shortening of incubation time was observed upon third passage. This shows that PoPrP is capable of forming infectious and neurotoxic prions in vivo if triggered by a compatible prion strain and if given enough time to develop. Both BSE and Nor98 rapidly adapts to the PoPrP host sequence, resulting in higher penetrance as well as in markedly shorter life span already in the second passage, well within the limits of normal life span for a mouse.

There are several crucial variables which impact the susceptibility of prion diseases and transmission studies.27 PrP sequence of host, PrP sequence of prion, prion strain, prion dosage, PrP expression level of host, host genetic background, route of transmission and neuroinvasiveness if peripherally infected.28 Importantly the PrP expression level corresponds to the rate of prion disease onset.1 This likely reflects 2 converging variables: a) PrP as a substrate to the prion misfolding reaction i.e. selfcatalyzed conversion and b) PrP as a mediator of neurotoxicity through interactions with misfolded PrP within prions.

The non-homologous recPrPs presented here and in,12 easily adapt to each other and form amyloid fibrils in accordance with what is seen in vivo when inoculum composed of BoPrP used to challenge mice expressing PoPrP (Fig. 3b).24-26 A review of the literature showed that BSE strains have a high degree of penetrance in both experimental and accidental transmission. Over 50% of the species reported to be susceptible to prion disease were infected by a BSE strain.19 Recent data form our lab shows that the promiscuity of BoPrP fibrils holds true also in the case of recombinant in vitro experiments. When cross-seeding human, bovine, porcine, feline and canine PrPs with any of the other, the recBoPrP seed outcompetes the other seeds in all instances except when the HuPrP acted as substrate (Data not shown). In this case recPoPrP fibrils have the highest seeding efficiency (Fig. 1). These findings in combination with the Torres experiments,24-26 implicate that a PoPrP substrate in vivo (in pigs) could adapt to an amyloidogenic prion strain of bovine or ovine prion disease and hence replicate in the new host.

For adaptation of experimental strains through multiple passages, donors are selected based on neurotoxicity (that is on TSE disease phenotype) not on basis of amyloid fibril formation. Hence the traits of transmissible amyloidotypic prion strains may be largely unexplored if these strains require more time to transform to neurotoxic strains e.g. as proposed by Baskakov’s model of deformed templating.8 There is experimental evidence for BSE transmission into pig via parenteral routes.16 with an incubation period of 2–3 years, well within what is to be considered normal lifespan. For a breeding sow in industrial scale pig farming that is 3–5 y (Bojne Andersson, personal communication).29,30 In small scale and hobby farming both sows and boars may be kept significantly longer. Collinge and Clarke.31 describe how prion titers reach transmissibility levels well before the prion burden is high enough to be neurotoxic and cause clinical disease. It is known that prion strains need time and serial passages to adapt. Knowing that pigs in modern farming are rarely kept for enough time for clinical signs to emerge in prion infected pigs it is important to be vigilant if there is a sporadic porcine spongiform encephalopathy (PSE) as has been seen in cattle (BASE) and sheep (Nor98). Hypothetically such a sporadic and then infectious event could further adapt and over a few generations have reached the point where clinical PSE is established within the time frame where pigs are being slaughtered for human consumption (Fig. 4).

FIGURE 4. Potential prion strain adaptation in pig. The red horizontal gradient indicates the hietherto unkown prion toxicity tolerance threshold for pigs, the blue vertical line indicates normal slaughter age for industrial pig farming, the green vertical line indicates the normal lifespan of a breeding sow in industrial scale pig farming, orange areas indicate window of neurotoxic prions before onset of clinical disease (dark orange indicates subclinical BSE as reported by Wells et al,16 pale orange indicate hypothetic outcome of PSE and strain adaptation. On the outmost right a potential subclinical sporadic PSE.

USE OF MATERIALS DERIVED FROM PIG IN VIEW OF PORCINE PrP AMYLOID

The pig is the most versatile species used by humans for food and other applications. Over 1,5 billion pigs are slaughtered each year worldwide for human use.32 Besides juicy pork sirloin other parts from pig are used for making remarkably diverse things such as musical instruments, china, leather, explosives, lubricants etc. Pig offal is used for human medicine, e.g., hormone preparations such as insulin and cerebrolysin, in xenographs, sutures, heparin and in gelatin for drug capsules.33,34

And that means not only pork, it means your pigskin wallet, catgut surgical suture...in tallow, in butter. It is undoubtedly in the blood supply. DC Gajdusek (From R. Rhodes ''Deadly Feast'' 35)

While the late Carleton Gajdusek had strong views in diverse areas of prion biology, according to journalist Richard Rhodes,35 he was correct on his prediction on BSE prions (vCJD) in the blood supply18 (see text box above). An opinionated scientist can sometimes be ignored due to a judgment of character and Gajdusek was certainly provocative. Notwithstanding society should remain vigilant on the possibility that Gajdusek was also prophetic on porcine prions given the exceptionally wide spread use of pigs in everyday human life and medicine. As discussed previously it is currently not established what relations transmissible neurotoxic prion strains and amyloid morphotypic mature APrP strains have. Given the hypotheses that amyloidotypic PrP conformations can transmit with low neurotoxicity.7,36 it is interesting to reflect on possible implications. Pigs are slaughtered at 6–8 months of age. Because amyloid deposition is associated with old age, this is likely far too young for spontaneous development of APrP amyloid from PoPrP as well as other amyloidogenic proteins. From the perspective of seeded amyloidogenesis it is however a potential ideal case for highly transmissible titers of APrP (Fig. 4). In such a scenario the potential of porcine prions constitutes the perfect storm, clinically silent due to neurotoxic resistance and with high titers of transmissibility. When it comes to prions CNS material is most heavily infected. In addition, however, fat tissue (to make lard and tallow) is known to harbor extraordinary amounts of amyloid in systemic amyloidoses.37 Amyloid fibrils of misfolded large proteins (AA, AL, ATTR) are notoriously hydrophobic due to the abnormal exposure of hydrophobic residues which normally in the folded structure being hidden in the protein core. The amyloid accumulation in fat tissue is likely a phase-separation from a rather hydrophilic environment in circulation toward the hydrophobic environment provided by adipocytes. Adipose tissue could in addition represent an in vivo environment well suitable for fibril formation. What about APrP?

In analysis of mice expressing Glycophosphatidylinositol, (GPI)-anchorless PrP, abdominal fat contains appreciable amounts of infectious prions in APrP isoform stained with ThS.38 Notably mice overexpressing anchorless PrP provides a silent carrier status for a long time prior to presenting symptoms and is severely afflicted by amyloid fibril formation following scrapie (RML) infection.39 Recall that this study showed that GPI-anchored PrP is needed to present clinical neurotoxicity. Evidently circulating anchorless-PrP (analogous to recPrP) is more amyloidogenic compared to GPI-anchored PrP and is poorly neuroinvasive.28 Amyloidosis is systemic in anchorless-PrP mice and is not limited to fat but is also found as extensive cardiac amyloid deposits.39 Interestingly cardiac APrP was recently reported in one BSE inoculated rhesus macaque which showed symptoms of cardiac distress prior to death from prion neurotoxicity.40 It is noteworthy that transgenic mice expressing PoPrP appear sensitive to strains with biochemical features of amyloidogenic prion strains i.e., BSE and Nor98.25,26,36 (Fig. 3b). We recently adopted the parallel inregister intermolecular b-sheet structural model of the APrP fibril from the Caughey lab to rationalize cross-seeding between various PrP sequences.12,41 It is tempting to use this structural model to speculate on the adaptation of mono-N-glycolsylated PoPrP at the expense of double-N-glycolylated PrP in the original BSE inoculum reported in the Torres experiments.25,26 In this APrP model monoglycosylated PrP at N197 is structurally compatible while N181 is not, due to burial in the in-register intermolecular cross-beta sheet (Fig. 5).

It appears that amyloidotypic prion strains, APrP, are transmissible but associated with lower neurotoxicity compared to diffuse aggregated PrP associated with synaptic PrP accumulations. It is possible that the amino acid substitutions in PoPrP compared to HuPrP and BoPrP are important for neurotoxic signal transmission (Fig. 2b, 5). The main issue hereby is that transmissibility of APrP will remain undetected unless used for surveillance. AA amyloidosis is frequent in many animals (e.g. cattle and birds) but is exceptionally rare in pigs.42 suggesting that APrP should it reside in pig fat would be traceable using newly developed screening methods.37


CONCLUDING REMARKS 

Should the topic of porcine PrP amyloid be more of a worry than of mere academic interest? Well perhaps. Prions are particularly insidious pathogens. A recent outbreak of peripheral neuropathy in human, suggests that exposure to aerosolized porcine brain is deleterious for human health.43,44 Aerosolization is a known vector for prions at least under experimental conditions.45-47 where a mere single exposure was enough for transmission in transgenic mice. HuPrP is seedable with BoPrP seeds and even more so with PoPrP seed (Fig. 1), indicating that humans could be infected by porcine APrP prions while neurotoxicity associated with spongiform encephalopathy if such a disease existed is even less clear. Importantly transgenic mice over-expressing PoPrP are susceptible to BSE and BSE passaged through domestic pigs implicating that efficient downstream neurotoxicity pathways in the mouse, a susceptible host for prion disease neurotoxicity is augmenting the TSE phenotype.25,26 Prions in silent carrier hosts can be infectious to a third species. Data from Collinge and coworkers.21 propose that species considered to be prion free may be carriers of replicating prions. Especially this may be of concern for promiscuous prion strains such as BSE.19,48 It is rather established that prions can exist in both replicating and neurotoxic conformations.49,50 and this can alter the way in which new host organisms can react upon cross-species transmission.51 The na€ıve host can either be totally resistant to prion infection as well as remain non-infectious, become a silent non-symptomatic but infectious carrier of disease or be afflicted by disease with short or long incubation time. The host can harbor and/or propagate the donor strain or convert the strain conformation to adapt it to the na€ıve host species. The latter would facilitate infection and shorten the incubation time in a consecutive event of intra-species transmission. It may be advisable to avoid procedures and exposure without proper biosafety precautions as the knowledge of silence carrier species is poor. One case of iatrogenic CJD in recipient of porcine dura mater graft has been reported in the literature.52 The significance of this finding is still unknown. The low public awareness in this matter is exemplified by the practice of using proteolytic peptide mixtures prepared from porcine brains (Cerebrolysin) as a nootropic drug. While Cerebrolysin may be beneficial for treatment of severe diseases such as vascular dementia,53 a long term follow-up of such a product for recreational use is recommended.

DISCLOSURE OF POTENTIAL CONFLICTS OF INTEREST

No potential conflicts of interest were disclosed

FUNDING

This work was supported by G€oran Gustafsson foundation, the Swedish research council Grant #2011-5804 (PH) and the Swedish Alzheimer association (SN).

REFERENCES



TUESDAY, APRIL 18, 2017 

*** EXTREME USA FDA PART 589 TSE PRION FEED LOOP HOLE STILL EXIST, AND PRICE OF POKER GOES UP ***


WEDNESDAY, MAY 17, 2017 

SHIC FUNDED STUDY SUGGESTS POTENTIAL FOR PATHOGEN TRANSMISSION VIA FEED


snip... see much more here ;

WEDNESDAY, APRIL 05, 2017 

Disease-associated prion protein detected in lymphoid tissues from pigs challenged with the agent of chronic wasting disease

http://chronic-wasting-disease.blogspot.com/2017/04/disease-associated-prion-protein.html

Terry S. Singeltary Sr.

Bacliff, Texas USA 77518

<flounder9@verizon.net> 

Saturday, January 9, 2016

Wednesday, July 29, 2015

Porcine Prion Protein Amyloid or mad pig disease PSE

Porcine Prion Protein Amyloid

 

DOI:

 

10.1080/19336896.2015.1065373

 

Received: 1 Jun 2015

 

Accepted: 17 Jun 2015

 

Accepted author version posted online: 28 Jul 2015

 

Abstract

 

Mammalian prions are composed of misfolded aggregated prion protein (PrP) with amyloid-like features. Prions are zoonotic disease agents that infect a wide variety of mammalian species including humans. Mammals and by-products thereof which are frequently encountered in daily life are most important for human health. It is established that bovine prions (BSE) can infect humans while there is no such evidence for any other prion susceptible species in the human food chain (sheep, goat, elk, deer) and largely prion resistant species (pig) or susceptible and resistant pets (cat and dogs respectively). PrPs from these species have been characterized using biochemistry, biophysics and neurobiology. Recently we studied PrPs from several mammals in vitro and found evidence for generic amyloidogenicity as well as cross-seeding fibril formation activity of all PrPs on the human PrP sequence regardless if the original species was resistant or susceptible to prion disease. Porcine PrP amyloidogenicity was among the studied. Experimentally inoculated pigs as well as transgenic mouse lines overexpressing porcine PrP have, in the past, been used to investigate the possibility of prion transmission in pigs. The pig is a species with extraordinarily wide use within human daily life with over a billion pigs harvested for human consumption each year. *** Here we discuss the possibility that the largely prion disease resistant pig can be a clinically silent carrier of replicating prions.

 


 

PORCINE SPONGIFORM ENCEPHALOPATHY PSE AND DEADSTOCK DOWNER PIGS

 

EXPERIMENTAL INTRACEREBRAL AND ORAL INOCULATION OF SCRAPIE TO SWINE: PRELIMINARY REPORT

 

Date: February 6, 2006 at 12:33 pm PST

 

Title: EXPERIMENTAL INTRACEREBRAL AND ORAL INOCULATION OF SCRAPIE TO SWINE: PRELIMINARY REPORT

 

SEE MORE HERE ;

 

 PORCINE SPONGIFORM ENCEPHALOPATHY PSE

 


 

Wednesday, July 06, 2011

 

Swine Are Susceptible to Chronic Wasting Disease by Intracerebral Inoculation

 

snip...

 

In the US, feeding of ruminant by-products to ruminants is prohibited, but feeding of ruminant materials to swine, mink and poultry still occurs. Although unlikely, the potential for swine to have access to TSE-contaminated feedstuffs exists.

 

snip...

 


 

Wednesday, July 06, 2011

 

Swine Are Susceptible to Chronic Wasting Disease by Intracerebral Inoculation

 

(see tonnage of mad cow feed in commerce USA...tss)

 


 

In an experimental study of the transmissibility of BSE to the pig, seven of 10 pigs, infected at 1-2 weeks of age by multiple-route parenteral inoculation with a homogenate of bovine brain from natural BSE cases developed lesions typical of spongiform encephalopathy.

 


 

Title: Experimental Intracerebral and Oral Inoculation of Scrapie to Swine: Preliminary Report

 

In the United States, feeding of ruminant by-products to ruminants is prohibited, but feeding of ruminant materials to swine and poultry still occurs. The potential for swine to have access to scrapie-contaminated feedstuffs exists, but the potential for swine to serve as a host for replication/accumulation of the agent of scrapie is unknown. The purpose of this study was to perform oral and intracerebral inoculation of the U.S. scrapie agent to determine the potential of swine as a host for the scrapie agent and their clinical susceptibility.

 

snip...

 

IN CONFIDENCE

 

EXPERIMENTAL PORCINE SPONGIFORM ENCEPHALOPATHY

 

1. CMO should be aware that a pig inoculated experimentally (ic, iv, and ip) with BSE brain suspension has after 15 months developed an illness, now confirmed as a spongiform encephalopathy. This is the first ever description of such a disease in a pig, although it seems there ar no previous attempts at experimental inoculation with animal material. The Southwood group had thought igs would not be susceptible. Most pigs are slaughtered when a few weeks old but there have been no reports of relevant neurological illness in breeding sows or other elderly pigs. ...see full text ;

 


 

IN CONFIDENCE

 

So it is plausible pigs could be preclinically affected with BSE but since so few are allowed to reach adulthood this has not been recognised through clinical disease. ...

 


 

snip...

 

CONFIDENTIAL

 

EXPERIMENTAL PORCINE SPONGIFORM ENCEPHALOPATHY

 

While this clearly is a cause for concern we should not jump to the conclusion that this means that pigs will necessarily be infected by bone and meat meal fed by the oral route as is the case with cattle. ...

 


 

we cannot rule out the possibility that unrecognised subclinical spongiform encephalopathy could be present in British pigs though there is no evidence for this: only with parenteral/implantable pharmaceuticals/devices is the theoretical risk to humans of sufficient concern to consider any action.

 


 

May I, at the outset, reiterate that we should avoid dissemination of papers relating to this experimental finding to prevent premature release of the information. ...

 


 

3. It is particularly important that this information is not passed outside the Department, until Ministers have decided how they wish it to be handled. ...

 


 

But it would be easier for us if pharmaceuticals/devices are not directly mentioned at all. ...

 


 

Our records show that while some use is made of porcine materials in medicinal products, the only products which would appear to be in a hypothetically ''higher risk'' area are the adrenocorticotrophic hormone for which the source material comes from outside the United Kingdom, namely America China Sweden France and Germany. The products are manufactured by Ferring and Armour. A further product, ''Zenoderm Corium implant'' manufactured by Ethicon, makes use of porcine skin - which is not considered to be a ''high risk'' tissue, but one of its uses is described in the data sheet as ''in dural replacement''. This product is sourced from the United Kingdom.....

 


 

snip...

 

It was not until . . . August 1990, that the result from the pig persuaded both SEAC and us to change our view and to take out of pig rations any residual infectivity that might have arisen from the SBOs.

 


 

4.303 The minutes of the meeting record that:

 

It was very difficult to draw conclusions from one experimental result for what may happen in the field. However it would be prudent to exclude specified bovine offals from the pig diet. Although any relationship between BSE and the finding of a spongiform encephalopathy in cats had yet to be demonstrated, the fact that this had occurred suggested that a cautious view should be taken of those species which might be susceptible. The 'specified offals' of bovines should therefore be excluded from the feed of all species. 17

 


 

IN CONFIENCE

 

EXPERIMENTAL PORCINE SPONGIFORM ENCEPHALOPATHY

 

1. CMO should be aware that a pig inoculated experimentally (ic, iv, and ip) with BSE brain suspension has after 15 months developed an illness, now confirmed as a spongiform encephalopathy. This is the first ever description of such a disease in a pig, although it seems there ar no previous attempts at experimental inoculation with animal material. The Southwood group had thought igs would not be susceptible. Most pigs are slaughtered when a few weeks old but there have been no reports of relevant neurological illness in breeding sows or other elderly pigs. ...see full text ;

 


 

 IN CONFIDENCE

 

So it is plausible pigs could be preclinically affected with BSE but since so few are allowed to reach adulthood this has not been recognised through clinical disease. ...

 


 

CONFIDENTIAL

 

EXPERIMENTAL PORCINE SPONGIFORM ENCEPHALOPATHY

 

While this clearly is a cause for concern we should not jump to the conclusion that this means that pigs will necessarily be infected by bone and meat meal fed by the oral route as is the case with cattle. ...

 


 

we cannot rule out the possibility that unrecognised subclinical spongiform encephalopathy could be present in British pigs though there is no evidence for this: only with parenteral/implantable pharmaceuticals/devices is the theoretical risk to humans of sufficient concern to consider any action.

 


 

May I, at the outset, reiterate that we should avoid dissemination of papers relating to this experimental finding to prevent premature release of the information. ...

 


 

3. It is particularly important that this information is not passed outside the Department, until Ministers have decided how they wish it to be handled. ...

 


 

But it would be easier for us if pharmaceuticals/devices are not directly mentioned at all. ...

 


 

Our records show that while some use is made of porcine materials in medicinal products, the only products which would appear to be in a hypothetically ''higher risk'' area are the adrenocorticotrophic hormone for which the source material comes from outside the United Kingdom, namely America China Sweden France and Germany. The products are manufactured by Ferring and Armour. A further product, ''Zenoderm Corium implant'' manufactured by Ethicon, makes use of porcine skin - which is not considered to be a ''high risk'' tissue, but one of its uses is described in the data sheet as ''in dural replacement''. This product is sourced from the United Kingdom.....

 


 

BSE TO PIGS NEWS RELEASE

 


 

CONFIDENTIAL

 

BSE: PRESS PRESENTATION

 


 


 


 


 


 

INDUSTRY RESPONSE TYPICAL

 


 

DEFENSIVE BRIEFING

 


 

CONFIDENTIAL

 

pigs & pharmaceuticals

 


 


 


 


 

COMMERCIAL IN CONFIDENCE COMMITTEE ON SAFETY OF MEDICINE NOT FOR PUBLICATION BOVINE SPONGIFORM ENCEPHALOPATHY WORKING GROUP

 

There are only two products using porcine brain and these use corticotrophin BP, made from porcine pituitary, source from outside the UK.............

 


 

snip...

 

7 OF 10 LITTLE PIGGIES WENT ON TO DEVELOP BSE;

 

1: J Comp Pathol. 2000 Feb-Apr; 122(2-3): 131-43. Related Articles,

 

Links

 

Click here to read

 

The neuropathology of experimental bovine spongiform encephalopathy in the pig.

 

Ryder SJ, Hawkins SA, Dawson M, Wells GA.

 

Veterinary Laboratories Agency Weybridge, Woodham Lane, New Haw, Addlestone, Surrey, KT15 3NB, UK.

 

In an experimental study of the transmissibility of BSE to the pig, seven of 10 pigs, infected at 1-2 weeks of age by multiple-route parenteral inoculation with a homogenate of bovine brain from natural BSE cases developed lesions typical of spongiform encephalopathy. The lesions consisted principally of severe neuropil vacuolation affecting most areas of the brain, but mainly the forebrain. In addition, some vacuolar change was identified in the rostral colliculi and hypothalamic areas of normal control pigs. PrP accumulations were detected immunocytochemically in the brains of BSE-infected animals. PrP accumulation was sparse in many areas and its density was not obviously related to the degree of vacuolation. The patterns of PrP immunolabelling in control pigs differed strikingly from those in the infected animals.

 

PMID: 10684682 [PubMed - indexed for MEDLINE]

 


 

snip...

 

In the United States, feeding of ruminant by-products to ruminants is prohibited, but feeding of ruminant materials to swine and poultry still occurs. The potential for swine to have access to scrapie-contaminated feedstuffs exists, but the potential for swine to serve as a host for replication/accumulation of the agent of scrapie is unknown. The purpose of this study was to perform oral and intracerebral inoculation of the U.S. scrapie agent to determine the potential of swine as a host for the scrapie agent and their clinical susceptibility.

 

see full text and more transmission studies here ;

 


 

Transgenic mice expressing porcine prion protein resistant to classical scrapie but susceptible to sheep bovine spongiform encephalopathy and atypical scrapie.

 

Emerg Infect Dis. 2009 Aug; [Epub ahead of print]

 


 

The case for mad pigs in the US

 

From the Consumer Policy Institute and Consumers Union: March 24, 1997

 

Stephen F. Sundlof, D.V.M., Ph.D Center for Veterinary Medicine Food and Drug Administration 7500 Standish Place, Room 482, HFV 1 RockvLIle, MD 20855 Dear Dr. Sundlof:

 

We are writing to you to submit information that has recently come to our attention which suggests that a TSE like disease (transmissible spongiform encephalopathy) might exist in pigs in the U.S. We believe this new informantion calls for intensive research and makes it urgent to ban the use of all mammalian proteins, including swine, in the feed of all food animals, until better answers are found.

 

The evidence for the potential PSE (porcine spongiform encephalopathy ) is as follows. In 1979, an FSQS veternarian, Dr. Masuo Doi, noticed some unusual central nervous system (CNS) symptoms in young (about 6 months old) hogs coming into a slaughter plant In Albany, New York. Since the plant received hogs from a wide variety of sources (New York, Canada, Indiana, Illinois, Ohio, and other Midwestern states) and was not a plant used to dealing with diseased animals, Dr. Doi thought that the problem might be affecting hogs slaughtered nationwide. So, he decided to conduct a detailed study on central nervous system (CNS) symptoms/disease in young hogs coming into that slaughter plant. The study ran for 15 months (January, 1979 to March, 1980) and consisted of extended observations of the behavior of animals with suspected CNS symptoms at the plant, followed by pathological, histopatholpgical, and microbiological work on tissues from various organs of particular animals after slaughter.

 

For his behavioral observational work, Dr. Doi extended the usual two day observation period to three to four days, during which he took careful notes on the animals' behavior and other vital signs. During the 15 month period of the study, some 106 animals exhibiting CNS symptoms were retained during antemortem inspection.

 

A 1980 paper that summarized Dr. Doi's findings on the clinical symptoms and incidence of the 'disease," contained descriptions of these symptoms that sound remarkably similar to the symptoms noted for bovine spongiform encephalopathy (BSE):

 

"Excitable or nervous temperament to external stimuli such as touch to the skin, handling and menacing approach to the animals is a common characteristic sign among swine affected with the disease.... In the advanced stage of the disease, manifestation of neurological signs are evidenced in the form of general ataxia . . . Many animals have been found to be "downers' at first observation; if the hindquarters of these downers are raised they may be able to walk one or two steps and then fall to the ground" (Doi et al., 1980: 2, 4). Indeed, a table of symptoms includes, for the early stage: "excitability and nervousness (squealing, smacking of lips, grinding of teath, chewing, gnawing ant foaming at mouth); stiffness of limbs . . . 'tic'; weakness of hindquarters; focal tremors of skeletal muscles"; and for the advanced stage: depression; ataxia; crossing over of limbs . . . kneeling posture . . . crawling". In addition to his clinical observations, Dr. Doi also made an 8 mm film of thirteen of the affected animals; film of two of the pigs was shown at the MPI National Pathology Meeting in Seattle, Washington on flay 20, 1979.

 

Dr. Doi sent tissue samples from suspect cases to the USDA's Eastern Laboratory in Athens, GA for pathological, histopathogical and microbiological work. Known infectious diseases were ruled out. As Dr. Doi points out, "Histopathological studies of tissue collected from the brain and spinal cord of these animals in the early stage of the disease show congestion, hemorrhage and neuronal degeneration. All animals in the advanced stage of the disease have been confined to have Encephalitis or Meningitis by MPI laboratory" (Doi et al., 1980: 5). Eventually some 60 animals were confirmed by the MPI Laboratory to have encephalitis or meningitis, with no ldentifiable cause. As pointed out in a paper presented at the 1979 MPI National Pathology Meetings,

 

"Since January, a number of hogs in this establishment have been found, in antemortem, to show what appears to be CNS. Sets of tissue samples were sent to the laboratory for examination, various tests were done which include histological study (E H stain), fluorescence antibody technique, virus neutralization and viral and bacteriological isolation. Differential diagnosis was also done to exclude vitamin B deficiency, post vaccination reaction, chlorinated hydrocarbon, arthritis, and transport stress" (Doi et al., 1979). The brains of the 60 animals were examined. The brain of one of these pigs, on histopathological analysis, exhibited signs reminiscent of a TSE. This histopathological work was performed by Dr. Karl Langheinrich, Pathologist-In-Charge at USDA's Eastern Laboratory in Athens, Georgia. According to the USDA FSQS laboratory report, dated early November, 1979, Dr. Langheinrich noted:

 

"Microscopic examination of the barrow tissues revealed a encephalopathy and diffuse gliosis characterized by vacuolated neurons, loss of neurons and gliosis in a confined region (nucleus) of the brain stem (anterior ventral midbrain). Only an empty sometimes divided vacuole was present instead of the normal morphology of a nerve cell. Occasionally a shriveled neuron was seen. According to . . . Pathology of Domestic Animals, . . . 'The degeneration of neurons, the reactivity of the glia .... are the classical hallmarks of viral infection of the central nervous system' .... Scrapie of sheep, and encephalopathy of mink, according to the literature, all produce focal vacuolation of the neurons similar to the kind as described for this pig. I was unable to locate any lead as to the cause of this interesting phenomenon in other species including swine'' (Langheinrich, 1979). Indeed, Dr. Langheinrich's main diagnosis was, " Encephalopathy and diffuse gliosis of undetermined etiology." Portions of the brain were sent for microbiological testing to a neurologist at the University of Georgia, where they came up negative for pseudo-rabies. The brain was unique enough that USDA scientists, such as Dr. Langheinrich and Or. Dot, mentioned it to student and scientific colleagues over the years.

 

In 1979-1980, BSE was completely unknown. However, both the behavior of the pigs, as well as the histopathology on at least one pig, both showed sign consistent with a porcine TSE. This raises particular concern became the affected animal was only 6 months old; in an animal this young, one would rust expect to see any physical signs of TSE in the brain. Histopathology of TSEs can be very variable, so that spongiform appearance (i.e. vacuolated neurons) are not always present. Behavioral changes can be seen in TSE-infected animals before any changes in brain morphology are visible. Dr. Clarence Gibbs, in testimony before a Congressional hearing on the TSE issue on January 29, 1997 made just this point:

 

''In the mid-1960s, we demonstrated with our French and English collaborators that during the early incubation of the TSEs, when the virus titer in the brain was very low, there were already marked functional changes, even though no pathology was yet detectable, even ultrastructurally. A month or hero later, polynucleation of neurons appeared in spider monkeys, incubating kuru, and somewhat later, microvacuolation and membrane changes visible only by electron microscopy. This preceded the pest appearance of astrogliosis and spongiform change. It was only much later that the classical scrapie TSE pathology appeared with virus titers in brain of 10 -5 or higher" (Gibbs, 1997; pg. 4). Given that TSEs can cause behavioral changes in infected animals before any physical changes in the brain can be seen, that the manifestation of TSE in the brain can be quite variable, and that changes in brain morphology are not usually seen in 6 month old animals, we are concerned that the brain of one pig actually showed physical evidence consistent with a TSE.

 

Following the announcement In March, 1996 of ten cases of new variant CJD (Creutzfeldt-Jakob Disease) in the United Kingdom and their possible connection to BSE, Drs. Doi, Langheinrich and others urged reinvestigation of this case.

 

In August, 1996, the USDA sent five slides, one of which was a histopathology slide, to Dr. Janice Miller of USDA's Agricultural Research Servicer . Dr. Miller stained four of the slides for prion protein (she didn't stain the H&E slide). Dr. Miller told Consumers Union that Dr. Patrick McCaskey, USDA/FSIS, in charge of the Research Center at Athens, GA, called her, told her that he had five slides that all showed "problems" and asked her to stain four of them. The H&E slide, which clearly show vacuoles in the neurons (one sign of TSE), wasn't stained because to stain for PrP entails removing the slide cover, baking the slide to destain it and then restaining it for PrP; they didn't want to risk destroying the H&E slide.

 

Dr. Doi had kept frozen samples of the brain and spinal chord of the suspect PSE pig in case the Eastern lab wanted more material for analysis. Unfortunately, these samples were discarded when the packing plant in Albany, NY closed in 1991. It appears that the brain material sent to the Univcrsity of Georgia may have been discarded. [pers com.. Dr. Doi 3/13/97]

 

Dr. Miller found that the PrP stained in the four pig slides was found only on the inside of neurons, while a positive control slide from a scrapie sheep showed massive amounts of extraneuronal staining. In a letter summarizing her results (copy attached), she concludes that the PrP stained in this pig was normal: "In the pig sections you will see a small particulate type of staining that is confined to neurons and as I indicated on the phone, I would interpret as normal PrP. It is in marked contrast to the massive amount of extraneuronal staining seen in the scrapie section" (Miller, 1996).

 

Unfortunately, Dr. Miller's finding toes not conclusively rule out a TSE. We are concerned that while British BSE and serapie create a massive amount of extraneuronal staining, there are TSEs where this isn't the case. Three experiments were done in He U.S. -- in Mission, TX (APHIS work), Pullman, Washington (ARS work), and Ames, Iowa (ARS work) -- to see whether sheep scrapie can possibly infect cows. In all the experiments, cattle were inoculated with tissue from scrapie -infected sheep primarily by intra-cranial injection, but in the case of the Texas and Iowa studies also by oral feeding -- to see if cattle were susceptible to scrapie at all. In all three experiments, the majority of cows injected in the brain with scrapie-infected sheep material (usually brains) also developed a fatal spongiform encephalopathy.

 

However, in all three examples, the symptoms of the spongifonn encephalopathy differed from "mad cow" disease ~ England, as did the appearances of slides from their brains. The brain lesions seen in all these animals were more variable than those seen in England. When Dr. Miller did similar staining for PrP from these brains (what she called "bovine scrapie") she only found PrP stains on the inside of the neurons, not the massive extraneuronal staining seen in BSE (Miller, pers. comm., March 7, 1997). Thus, Dr. Miller's finding of PrP stains only inside the neurons in the suspect pigs is not particularly reassuring.

 

In November 1996, USDA sent the single histopathology slide to Dr. William Hadlow, one of the foremost spongiform encephalopathy pathologists in the world. (For unknown reasons, Dr. Hadlow was only sent the one slide; he was not told of the existence of the other slides, nor of Dr. Miller's findings, nor was he told or given the behavioral report from Dr. Doi or the morphology work by Dr. Langheinrich, or shown film of the affected pigs [Dr. Hadlow, pers. com., 3/13/97] From this single slide, Dr. Hadlow found some evidence consistent with TSEs but not enough for a conclusive diagnosis. He noted that the slide contained vacuoles inside neurons, one of the signs of a TSE (Dr. Langheinrich had noted this as well).

 

However, since such vacuoles occasionally occur normally in pigs, he thought that was not something special: "About twelve (12) neurons in the parasympathetic nucleus have unilocular optically empty vacuoles in the perikaryon. This is the site where such vacuolated neurons have been seen in the swine (as well as in cats and sheep) as an incidental finding. So I do not think such cells have any significance in this pig" (Hadlow, 1996). However, he did see evidence, Including changes in astrocytes, that suggested a TSE, but without examining other parts of the brain to look for other evidence of TSE, he couldn't be sure:

 

"I am impressed, though, with what seems to be an increase in the number of astrocytes in the section. Some astrocytes are in clusters, some are enlarged and vesicular. Where they are most numerous, a few rod cells (activated microglia) are seen. These findings suggest some perturbation of the nervous tissue. Although such a global response occurs in the transmissible spongifonn encephalopathies, I do no! know its significance in this case without examining other parts of the brain for changes characteristic of these diseases. Thus, from looking; at this one (1) section of brain, I cannot conclude that the pig was affected with a scrapie-like spongiform encephalopathy" (Hadlow, 1996). In sum, Dr. Hadlow~s letter does not rule out the possibility of a TSE. He says that there is suggestive evidence, but that he would need to look at other slides/sections of the brain, to make a conclusive diagnosis.

 

In our view, the implications of this data are extremely serious. Experiments in the United Kingdom have shown that pigs are susceptible to BSE. Pigs inoculated with BSE develop a TSE (Dawson et al., 1990). Feeding experiments are underway in the UK to see if BSE can be orally transmitted to pigs; as of March, 1997, some 6 years after the start of the experiment, none of the pigs fed BSE brain have come down with a TSE. Unfortunately the design of this experiment severely limits what we will learn from it, and will most likely not tell us conclusively if pigs can get BSE from feed. It turns out that the pigs were not fed BSE brain continuously. Rather, the pigs were only fed BSE brain material on three days, over a three week period (i.e.. one day each week). Following these three doses, the pigs were never fed contaminated material again. The total amount of infective material given to the pigs was therefore quite small. Thus, a negative finding would be hard to interpret and would not mean that BSE is not orally active in pigs.

 

We believe that as a top priority USDA should conduct follow-up studies to look for potential CNS/PSE cases in pigs (we plan to communicate about this to USDA separately). In brief, we feel that the following kinds of studies need to be done:

 

i) TSE pathology experts should examine all the slides from the suspect pig (2709). To our knowledge, at least 12 separate slides exist.

 

ii) Determine if any brain material from the suspect pig (2709) still exists at the Unlverslty of Georgia. If so, this material should be retrieved and used for transmission studies. In particular, suckling pigs should be inoculated with the material and then permitted to live unto they die of a disease or old age, at which point their brains should be examined for physical signs of a TSE as well as for immunchistochemical evidence (i.e. staining looking for the abnormal PrP).

 

iii) Increase antemortem inspection for CNS symptoms at hog facilities. Inspectors should be trained to detect the subtle CNS symptoms seen in the Doi et al. study. At a select number of slaughter facilities, animals exhibiting CNS symptoms should be removed and held for observation until they die, at which time their brains should be examined for evidence of a TSE.

 

iv) Research on CNS symptoms among Me 6,000 or so breeding sows which are permitted to live for 3+ years. Sows exhibiting CNS symptoms should be removed and held for observation until they die, at which time then brains should be exernined for evidence of a TSE.

 

While such work is underway, given the above inforrnabon, we believe that as a precutionary measure the FDA must expand the proposed ruminant plus mink-to-ruminnant feed ban to prevent protein from any material, including hogs, being fed to any food animal.

 

Sincerely,

 

Michael Hansen, Ph.D Research Associate

 

Jean Halloran Director

 

References

 

Dawson, M., Wells, G.A.H., Parker, B.N;J. and A.C Scott. 1990. Primary parental transmission of bovine spongiform encephalopathy to the pig. Veternary Record, pg. 338.

 

Doi, M., Matzner, N.D. and C. Rothaug. 1979. Observation of CNS disease in market hogs at Est. 893 Tobin Packing Co., Inc. Albany, New York. United States Department of Agriculture, Food Safety and Quality.Service, Meat and Poultry Inspection Service. 7pp.

 

Doi, M, Langheinrich, K. and F. Rellosa. 1980. Observations of CNS signs in hogs at Est. 893 Tobin Packing C:o., Inc. Presented by Dr. Lngheinrich at the MPI National Pathology Meeting in Seattle, Washington on July 20, 1979.

 

Gibbs, C. 1997. Statement to the Committee on Governnent Reform and Oversight, Subcommittee on Human Resources and Intergovernmental Relations, U.S. House of Representatives. January 29,1997.

 

Hadlow, WJ. 1996. Letter to Patrick McCaskey, USDA/FSIS/Eastem Lab, dated November 13, 1996.

 

Langheinrich, KA. 1979. USDA/FSQS Laboratory report on specimen 2709. Dated November 8, 1979

 

Miller, J. 1996. Letter to Patrick McCaskey, USDA/ESIS/Eastern Lab, dated September 6, 1996.

 

Dr. Janice Miller, ARS

 


 

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...

 


 

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

 

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

 

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

 

HOUND SURVEY

 

I am sorry, but I really could have been a co-signatory of Gerald's minute.

 

I do NOT think that we can justify devoting any resources to this study, especially as larger and more important projects such as the pathogenesis study will be quite demanding.

 

If there is a POLITICAL need to continue with the examination of hound brains then it should be passed entirely to the VI Service.

 

J W WILESMITH Epidemiology Unit 18 October 1991

 

Mr. R Bradley

 

cc: Mr. G A H Wells

 


 

3.3. Mr R J Higgins in conjunction with Mr G A Wells and Mr A C Scott would by the end of the year, indentify the three brains that were from the ''POSITIVE'' end of the lesion spectrum.

 


 

*** OR-09: Canine spongiform encephalopathy—A new form of animal prion disease ***

 

Monique David, Mourad Tayebi UT Health; Houston, TX USA

 

It was also hypothesized that BSE might have originated from an unrecognized sporadic or genetic case of bovine prion disease incorporated into cattle feed or even cattle feed contaminated with prion-infected human remains.1 However, strong support for a genetic origin of BSE has recently been demonstrated in an H-type BSE case exhibiting the novel mutation E211K.2 Furthermore, a specific prion protein strain causing BSE in cattle is believed to be the etiological agent responsible for the novel human prion disease, variant Creutzfeldt-Jakob disease (vCJD).3 Cases of vCJD have been identified in a number countries, including France, Italy, Ireland, the Netherlands, Canada, Japan, US and the UK with the largest number of cases. Naturally occurring feline spongiform encephalopathy of domestic cats4 and spongiform encephalopathies of a number of zoo animals so-called exotic ungulate encephalopathies5,6 are also recognized as animal prion diseases, and are thought to have resulted from the same BSE-contaminated food given to cattle and humans, although and at least in some of these cases, a sporadic and/or genetic etiology cannot be ruled out. The canine species seems to display resistance to prion disease and no single case has so far been reported.7,8 Here, we describe a case of a 9 week old male Rottweiler puppy presenting neurological deficits; and histological examination revealed spongiform vacuolation characteristic of those associated with prion diseases.9 Initial biochemical studies using anti-PrP antibodies revealed the presence of partially proteinase K-resistant fragment by western blotting. Furthermore, immunohistochemistry revealed spongiform degeneration consistent with those found in prion disease and displayed staining for PrPSc in the cortex.

 

Of major importance, PrPSc isolated from the Rottweiler was able to cross the species barrier transmitted to hamster in vitro with PMCA and in vivo (one hamster out of 5). Futhermore, second in vivo passage to hamsters, led to 100% attack rate (n = 4) and animals displayed untypical lesional profile and shorter incubation period.

 

In this study, we show that the canine species might be sensitive to prion disease and that PrPSc isolated from a dog can be transmitted to dogs and hamsters in vitro using PMCA and in vivo to hamsters.

 

If our preliminary results are confirmed, the proposal will have a major impact on animal and public health and would certainly lead to implementing new control measures for ‘canine spongiform encephalopathy’ (CSE).

 

References 1. Colchester AC, Colchester NT. The origin of bovine spongiform encephalopathy: the human prion disease hypothesis. Lancet 2005; 366:856-61; PMID:16139661; http:// dx.doi.org/10.1016/S0140-6736(05)67218-2.

 

2. Richt JA, Hall SM. BSE case associated with prion protein gene mutation. PLoS Pathog 2008; 4:e1000156; PMID:18787697; http://dx.doi.org/10.1371/journal. ppat.1000156.

 

3. Collinge J. Human prion diseases and bovine spongiform encephalopathy (BSE). Hum Mol Genet 1997; 6:1699-705; PMID:9300662; http://dx.doi.org/10.1093/ hmg/6.10.1699.

 

4. Wyatt JM, Pearson GR, Smerdon TN, Gruffydd-Jones TJ, Wells GA, Wilesmith JW. Naturally occurring scrapie-like spongiform encephalopathy in five domestic cats. Vet Rec 1991; 129:233-6; PMID:1957458; http://dx.doi.org/10.1136/vr.129.11.233.

 

5. Jeffrey M, Wells GA. Spongiform encephalopathy in a nyala (Tragelaphus angasi). Vet Pathol 1988; 25:398-9; PMID:3232315; http://dx.doi.org/10.1177/030098588802500514.

 

6. Kirkwood JK, Wells GA, Wilesmith JW, Cunningham AA, Jackson SI. Spongiform encephalopathy in an arabian oryx (Oryx leucoryx) and a greater kudu (Tragelaphus strepsiceros). Vet Rec 1990; 127:418-20; PMID:2264242.

 

7. Bartz JC, McKenzie DI, Bessen RA, Marsh RF, Aiken JM. Transmissible mink encephalopathy species barrier effect between ferret and mink: PrP gene and protein analysis. J Gen Virol 1994; 75:2947-53; PMID:7964604; http://dx.doi.org/10.1099/0022-1317- 75-11-2947.

 

8. Lysek DA, Schorn C, Nivon LG, Esteve-Moya V, Christen B, Calzolai L, et al. Prion protein NMR structures of cats, dogs, pigs, and sheep. Proc Natl Acad Sci U S A 2005; 102:640-5; PMID:15647367; http://dx.doi.org/10.1073/pnas.0408937102.

 

9. Budka H. Neuropathology of prion diseases. Br Med Bull 2003; 66:121-30; PMID:14522854; http://dx.doi.org/10.1093/bmb/66.1.121.

 


 

Monday, March 26, 2012

 

CANINE SPONGIFORM ENCEPHALOPATHY: A NEW FORM OF ANIMAL PRION DISEASE

 


 

Monday, March 8, 2010

 

Canine Spongiform Encephalopathy aka MAD DOG DISEASE

 


 

Wednesday, July 29, 2015

 

Acquired transmissibility of sheep-passaged L-type bovine spongiform encephalopathy prion to wild-type mice

 


 

Wednesday, July 15, 2015

 

*** Additional BSE TSE prion testing detects pathologic lesion in unusual brain location and PrPsc by PMCA only, how many cases have we missed?

 


 

IBNC Tauopathy or TSE Prion disease, it appears, no one is sure

 

Posted by flounder on 03 Jul 2015 at 16:53 GMT

 


 

SEE FULL TEXT ;

 


 

 

Terry S. Singeltary Sr. Bacliff, Texas USA 77518 flounder9@verizon.net

Friday, April 20, 2012

Ultrastructural findings in pigs experimentally infected with bovine spongiform encephalopathy agent

Ultrastructural findings in pigs experimentally infected with bovine spongiform encephalopathy agent


Pawel P. Liberski1, Beata Sikorska1, Gerald A.H. Wells2, Steve A.C. Hawkins3, Michael Dawson3, Marion M. Simmons2 1Department of Molecular Pathology and Neuropathology, Medical University of Lodz, Poland, 2TSE Department, and 3Specialist Scientific Services Department, Animal Health and Veterinary Laboratories Agency, Weybridge, Addlestone, Surrey, United Kingdom Folia Neuropathol 2012; 50 (1): 89-98


A b s t r a c t


We report here an electron microscopic study of selected nervous system tissues from pigs infected experimentally with the agent of bovine spongiform encephalopathy (BSE). Generally, the ultrastructural neuropathology of BSE-affected pig brain resembled that of BSE-affected cattle brain. Spongiform change, in the form of membrane-bound vacuoles separated by septae into secondary chambers, dominated the pathology. Numerous astrocytic processes were visible in close conjunction with elongated microglial cells. Neuronal degeneration presented as either dystrophic neurites or by the formation of autophagic vacuoles. Altered subcellular organelles: mitochondria, electron-dense bodies, autophagic vacuoles, neurofilaments and “branching-cisterns” accumulated in abnormal neurites. Autophagic vacuoles appeared as neuronal cytoplasm of increased electron-density sequestrated by intracytoplasmic membranes. Tubulovesicular structures were numerous, particularly in the cerebellum. Unusual crystalloids were observed in the white matter. In conclusion, experimental BSE in pigs demonstrated ultrastructural pathology in keeping with that observed in other spongiform encephalopathies.


Key words: prions, BSE, pigs, ultrastructure.


snip...


Material and methods


Experiment design and inoculation procedure


The pigs were infected at 1-2 weeks of age by multiple- route parenteral inoculation with a homogenate of bovine brain from natural BSE cases, as described in full previously [76,86,87]. All challenges were carried out in accordance with the Animals (Scientific Procedures) Act, 1986, under licence from the UK Home Office. Animals were sedated with azoperone (Stresnil; Janssen Animal Health) and killed by the intravenous injection of pentobarbitone sodium followed by exsanguination. When clinical disease developed, animals were killed and samples collected immediately postmortem.




snip...


Electron microscopy


Multiple samples, comprised 2-3 mm3, of cerebral cortex, brain stem at the level of vestibular nuclei, ventral horns of the spinal cord, cerebellum and dorsal root ganglia, selected on the basis of the previously determined prevalence of light-microscopy changes [76,87], were fixed immediately after dissection in 2.5% glutaraldehyde, freshly prepared in phosphate buffer (pH 7.4), then postfixed in 1% osmium tetroxide and processed for routine electron microscopy. Comparable areas of brain from uninoculated pigs served as controls.


snip...


Results


In general, the ultrastructural features of BSE-affected pig brain were similar to those of BSE-affected cattle [46,66,67] and humans with TSEs [60,61]. Spongiform change in the form of membrane-bound vacuoles (Fig. 1) separated by membranes curled into secondary chambers dominated the pathology. A dense astrocytic reaction was accompanied by abundant elongated microglial cells. Of particular note was the finding of numerous astrocytic processes in close conjunction with microglial cells. Neuronal degeneration presented as either neuroaxonal dystrophy, as evidenced by dystro - phic neurites, or autophagic vacuoles. Dystrophic neurites accumulated altered subcellular organelles: mitochondria (Fig. 1B), electron-dense bodies, neurofilaments and “branching-cisterns” (Fig. 2). Autopha - gic vacuoles appeared as a part or parts of the neuronal cytoplasm sequestrated by intracytoplasmic membranes (Fig. 3). Sequestrated cytoplasm was of higher electron density than the remaining cytosol. Discontinuity of plasma membranes was occasionally seen (Fig. 3B, arrow). Tubulovesicular structures (TVS) were numerous with the highest number of affected processes in the cerebellum (Fig. 4). Many large multivesicular bodies were seen (Fig. 5).












PORCINE SPONGIFORM ENCEPHALOPATHY PSE








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