Wednesday, July 29, 2015

Further characterisation of transmissible spongiform encephalopathy phenotypes after inoculation of cattle with two temporally separated sources of sheep scrapie from Great Britain

BMC Res Notes. 2015 Jul 24;8:312. doi: 10.1186/s13104-015-1260-3.

 

Further characterisation of transmissible spongiform encephalopathy phenotypes after inoculation of cattle with two temporally separated sources of sheep scrapie from Great Britain.

 

Konold T1, Nonno R2, Spiropoulos J3, Chaplin MJ4, Stack MJ5, Hawkins SA6, Cawthraw S7, Wilesmith JW8, Wells GA9, Agrimi U10, Di Bari MA11, Andréoletti O12, Espinosa JC13, Aguilar-Calvo P14, Torres JM15.

 

 Author information

 

Abstract

 

BACKGROUND:

 

The infectious agent responsible for the bovine spongiform encephalopathy (BSE) epidemic in Great Britain is a transmissible spongiform encephalopathy (TSE) strain with uniform properties but the origin of this strain remains unknown. Based on the hypothesis that classical BSE may have been caused by a TSE strain present in sheep, cattle were inoculated intracerebrally with two different pools of brains from scrapie-affected sheep sourced prior to and during the BSE epidemic to investigate resulting disease phenotypes and characterise their causal agents by transmission to rodents.

 

RESULTS:

 

As reported in 2006, intracerebral inoculation of cattle with pre-1975 and post-1990 scrapie brain pools produced two distinct disease phenotypes, which were unlike classical BSE. Subsequent to that report none of the remaining cattle, culled at 10 years post inoculation, developed a TSE. Retrospective Western immunoblot examination of the brains from TSE cases inoculated with the pre-1975 scrapie pool revealed a molecular profile similar to L-type BSE. The inoculation of transgenic mice expressing the bovine, ovine, porcine, murine or human prion protein gene and bank voles with brains from scrapie-affected cattle did not detect classical or atypical BSE strains but identified two previously characterised scrapie strains of sheep.

 

CONCLUSIONS:

 

Characterisation of the causal agents of disease resulting from exposure of cattle to naturally occurring scrapie agents sourced in Great Britain did not reveal evidence of classical or atypical BSE, but did identify two distinct previously recognised strains of scrapie. Although scrapie was still recognizable upon cattle passage there were irreconcilable discrepancies between the results of biological strain typing approaches and molecular profiling methods, suggesting that the latter may not be appropriate for the identification and differentiation of atypical, particularly L-type, BSE agents from cattle experimentally infected with a potential mixture of classical scrapie strains from sheep sources.

 

PMID: 26205536 [PubMed - in process]

 


 

Conclusions

 

Two different disease phenotypes were produced after intracerebral inoculation of cattle with scrapie brain pools sourced pre-1975 and post-1990 in GB, which were not readily explained by any differences in PrP genotype of the cattle. Based on pathological and molecular characteristics and biological characterisation in bank voles and transgenic mice there was no clear evidence of an agent derived from the cattle resembling classical or atypical forms of BSE. Transmissions in bank voles identified previously isolated scrapie strains and some similarities to the experimental isolate CH1641. Contrary to the transmission results in rodents, the results for the molecular techniques, which have been adopted for the detection of atypical BSE cases, suggest that they may not be appropriate for differentiating WB profiles in cattle following infection from an ovine scrapie source.

 


 

 Wednesday, January 18, 2012

 

Selection of Distinct Strain Phenotypes in Mice Infected by Ovine Natural Scrapie Isolates Similar to CH1641 Experimental Scrapie

 

Journal of Neuropathology & Experimental Neurology:

 

February 2012 - Volume 71 - Issue 2 - p 140–147

 

doi: 10.1097/NEN.0b013e3182439519

 

Original Articles

 

Selection of Distinct Strain Phenotypes in Mice Infected by Ovine Natural Scrapie Isolates Similar to CH1641 Experimental Scrapie

 

Vulin, Johann PhD; Beck, Katy E. PhD; Bencsik, Anna PhD; Lakhdar, Latefa PhD; Spiropoulos, John PhD; Baron, Thierry PhD

 

Supplemental Author Material

 

Abstract

 

Abstract: A few cases of transmissible spongiform encephalopathies in sheep have been described in France in which the protease-resistant prion protein (PrPres) exhibited some features in Western blot of experimental bovine spongiform encephalopathy in sheep. Their molecular characteristics were indistinguishable from those produced in the CH1641 experimental scrapie isolate. Four of these CH1641-like isolates were inoculated intracerebrally into wild-type C57Bl/6 mice. In striking contrast to previous results in ovine transgenic mice, CH1641 transmission in wild-type mice was efficient. Several components of the strain signature, that is, PrPres profile, brain distribution, and morphology of the deposits of the disease-associated prion protein, had some similarities with “classical” scrapie and clearly differed from both bovine spongiform encephalopathy in sheep and CH1641 transmission in ovine transgenic mice. These results on CH1641-like isolates in wild-type mice may be consistent with the presence in these isolates of mixed conformers with different abilities to propagate and mediate specific disease phenotypes in different species.

 

Bovine spongiform encephalopathy, CH1641, Prion disease pathogenesis

 

© 2012 American Association of Neuropathologists, Inc

 


 

Wednesday, January 18, 2012

 

BSE IN GOATS CAN BE MISTAKEN FOR SCRAPIE

 

February 1, 2012

 


 

TSE PRION UPDATE USA 2012

 

re-BSE in goats can be mistaken for scrapie

 


 

Wednesday, January 18, 2012

 

Selection of Distinct Strain Phenotypes in Mice Infected by Ovine Natural Scrapie Isolates Similar to CH1641 Experimental Scrapie

 

Journal of Neuropathology & Experimental Neurology:

 

February 2012 - Volume 71 - Issue 2 - p 140–147

 


 

In the US, scrapie is reported primarily in sheep homozygous for 136A/171Q (AAQQ) and the disease phenotype is similar to that seen with experimental strain CH1641.

 


 

Thursday, July 14, 2011

 

Histopathological Studies of "CH1641-Like" Scrapie Sources Versus Classical Scrapie and BSE Transmitted to Ovine Transgenic Mice (TgOvPrP4)

 


 

EVIDENCE OF SCRAPIE IN SHEEP AS A RESULT OF FOOD BORNE EXPOSURE

 

This is provided by the statistically significant increase in the incidence of sheep scrape from 1985, as determined from analyses of the submissions made to VI Centres, and from individual case and flock incident studies. ........

 


 

RISK OF BSE TO SHEEP VIA FEED

 


 

Marion Simmons communicated surprising evidence for oral transmissibility of Nor98/atypical scrapie in neonatal sheep and although bioassay is ongoing, infectivity of the distal ileum of 12 and 24 month infected sheep is positive in Tg338 mice.

 


 

SUMMARY REPORTS OF MAFF BSE TRANSMISSION STUDIES AT THE CVL ;

 


 

THE RISK TO HUMANS FROM SHEEP;

 


 

EXPERIMENTAL TRANSMISSION OF BSE TO SHEEP

 


 

SHEEP AND BSE

 

PERSONAL AND CONFIDENTIAL

 

SHEEP AND BSE

 

A. The experimental transmission of BSE to sheep.

 

Studies have shown that the ''negative'' line NPU flock of Cheviots can be experimentally infected with BSE by intracerebral (ic) or oral challenge (the latter being equivalent to 0.5 gram of a pool of four cow brains from animals confirmed to have BSE).

 


 

RB264

 

BSE - TRANSMISSION STUDIES

 


 

Monday, March 21, 2011

 

Sheep and Goat BSE Propagate More Efficiently than Cattle BSE in Human PrP Transgenic Mice

 

snip...

 

On the other hand, this component would not be distinguishable from bovine-passaged BSE prions due to the current limits of the standard biological methods and/or the molecular tools employed here to characterize prion strains. Whatever the mechanism, the notion that a passage through an intermediate species can profoundly alter prion virulence for the human species has important public-health issues, regarding emerging and/or expanding TSEs, like atypical scrapie or CWD.

 

snip...

 

Taken all together, our results suggest that the possibility of a small ruminant BSE prion as vCJD causal agent could not be ruled out, which has important implications on public and animal health policies. On one hand, although the exact magnitude and characteristic of the vCJD epidemic is still unclear, its link with cattle BSE is supported by strong epidemiological ground and several experimental data. On the other hand, the molecular typing performed in our studies, indicates that the biochemical characteristics of the PrPres detected in brains of our sheep and goat BSE-inoculated mice seem to be indistinguishable from that observed in vCJD. Considering the similarity in clinical manifestation of BSE- and scrapie-affected sheep [48], a masker effect of scrapie over BSE, as well as a potential adaptation of the BSE agent through subsequent passages, could not be ruled out. As BSE infected sheep PrPSc have been detected in many peripheral organs, small ruminant-passaged BSE prions might be a more widespread source of BSE infectivity compared to cattle [19], [49], [50]. This fact is even more worrying since our transmission studies suggest that apparently Met129 human PrP favours a BSE agent with ovine rather than a bovine sequence. Finally, it is evident that, although few natural cases have been described and so far we cannot draw any definitive conclusion about the origin of vCJD, we can not underestimate the risk of a potential goat and/or sheep BSE agent.

 

snip...

 


 

Technical Abstract:

 

Prion strains may vary in their ability to transmit to humans and animals. Few experimental studies have been done to provide evidence of differences between U.S. strains of scrapie, which can be distinguished by incubation times in inbred mice, microscopic lesions, immunoreactivity to various antibodies, or molecular profile (electrophoretic mobility and glycoform ratio). Recent work on two U.S. isolates of sheep scrapie supports that at least two distinct strains exist based on differences in incubation time and genotype of sheep affected. One isolate (No. 13-7) inoculated intracerebrally caused scrapie in sheep AA at codon 136 (AA136) and QQ at codon 171 (QQ171) of the prion protein in an average of 19 months post-inoculation (PI) whereas a second isolate (No. x124) caused disease in less than 12 months after oral inoculation in AV136/QQ171 sheep. Striking differences were evident when further strain analysis was done in R111, VM, C57Bl6, and C57Bl6xVM (F1) mice. No. 13-7 did not induce disease in any mouse strain at any time post-inoculation (PI) nor were brain tissues positive by western blot (WB). Positive WB results were obtained from mice inoculated with isolate No. x124 starting at day 380 PI. Incubation times averaged 508, 559, 601, and 633 days PI for RIII, C57Bl6, VM, and F1 mice, respectively. Further passage will be required to characterize these scrapie strains in mice. This work provides evidence that multiple scrapie strains exist in U.S. sheep.

 


 

One of these isolates (TR316211) behaved like the CH1641 isolate, with PrPres features in mice similar to those in the sheep brain. From two other isolates (O100 and O104), two distinct PrPres phenotypes were identified in mouse brains, with either high (h-type) or low (l-type) apparent molecular masses of unglycosylated PrPres, the latter being similar to that observed with CH1641, TR316211, or BSE. Both phenotypes could be found in variable proportions in the brains of the individual mice. In contrast with BSE, l-type PrPres from "CH1641-like" isolates showed lower levels of diglycosylated PrPres. From one of these cases (O104), a second passage in mice was performed for two mice with distinct PrPres profiles. This showed a partial selection of the l-type phenotype in mice infected with a mouse brain with predominant l-type PrPres, and it was accompanied by a significant increase in the proportions of the diglycosylated band. These results are discussed in relation to the diversity of scrapie and BSE strains.

 


 

1: J Infect Dis 1980 Aug;142(2):205-8

 

Oral transmission of kuru, Creutzfeldt-Jakob disease, and scrapie to nonhuman primates.

 

Gibbs CJ Jr, Amyx HL, Bacote A, Masters CL, Gajdusek DC.

 

Kuru and Creutzfeldt-Jakob disease of humans and scrapie disease of sheep and goats were transmitted to squirrel monkeys (Saimiri sciureus) that were exposed to the infectious agents only by their nonforced consumption of known infectious tissues. The asymptomatic incubation period in the one monkey exposed to the virus of kuru was 36 months; that in the two monkeys exposed to the virus of Creutzfeldt-Jakob disease was 23 and 27 months, respectively; and that in the two monkeys exposed to the virus of scrapie was 25 and 32 months, respectively. Careful physical examination of the buccal cavities of all of the monkeys failed to reveal signs or oral lesions. One additional monkey similarly exposed to kuru has remained asymptomatic during the 39 months that it has been under observation.

 

snip...

 

The successful transmission of kuru, Creutzfeldt-Jakob disease, and scrapie by natural feeding to squirrel monkeys that we have reported provides further grounds for concern that scrapie-infected meat may occasionally give rise in humans to Creutzfeldt-Jakob disease.

 

PMID: 6997404

 


 

12/10/76 AGRICULTURAL RESEARCH COUNCIL REPORT OF THE ADVISORY COMMITTE ON SCRAPIE Office Note CHAIRMAN: PROFESSOR PETER WILDY

 

snip...

 

A The Present Position with respect to Scrapie A] The Problem Scrapie is a natural disease of sheep and goats. It is a slow and inexorably progressive degenerative disorder of the nervous system and it ia fatal. It is enzootic in the United Kingdom but not in all countries. The field problem has been reviewed by a MAFF working group (ARC 35/77). It is difficult to assess the incidence in Britain for a variety of reasons but the disease causes serious financial loss; it is estimated that it cost Swaledale breeders alone $l.7 M during the five years 1971-1975. A further inestimable loss arises from the closure of certain export markets, in particular those of the United States, to British sheep. It is clear that scrapie in sheep is important commercially and for that reason alone effective measures to control it should be devised as quickly as possible. Recently the question has again been brought up as to whether scrapie is transmissible to man. This has followed reports that the disease has been transmitted to primates.

 

One particularly lurid speculation (Gajdusek 1977) conjectures that the agents of scrapie, kuru, Creutzfeldt-Jakob disease and transmissible encephalopathy of mink are varieties of a single "virus". The U.S. Department of Agriculture concluded that it could "no longer justify or permit scrapie-blood line and scrapie-exposed sheep and goats to be processed for human or animal food at slaughter or rendering plants" (ARC 84/77)" The problem is emphasised by the finding that some strains of scrapie produce lesions identical to the once which characterise the human dementias" Whether true or not. the hypothesis that these agents might be transmissible to man raises two considerations. First, the safety of laboratory personnel requires prompt attention. Second, action such as the "scorched meat" policy of USDA makes the solution of the acrapie problem urgent if the sheep industry is not to suffer grievously.

 

snip...

 

76/10.12/4.6

 


 

Nature. 1972 Mar 10;236(5341):73-4.

 

Transmission of scrapie to the cynomolgus monkey (Macaca fascicularis).

 

Gibbs CJ Jr, Gajdusek DC. Nature 236, 73 - 74 (10 March 1972); doi:10.1038/236073a0

 

Transmission of Scrapie to the Cynomolgus Monkey (Macaca fascicularis)

 

C. J. GIBBS jun. & D. C. GAJDUSEK National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, Maryland

 

SCRAPIE has been transmitted to the cynomolgus, or crab-eating, monkey (Macaca fascicularis) with an incubation period of more than 5 yr from the time of intracerebral inoculation of scrapie-infected mouse brain. The animal developed a chronic central nervous system degeneration, with ataxia, tremor and myoclonus with associated severe scrapie-like pathology of intensive astroglial hypertrophy and proliferation, neuronal vacuolation and status spongiosus of grey matter. The strain of scrapie virus used was the eighth passage in Swiss mice (NIH) of a Compton strain of scrapie obtained as ninth intracerebral passage of the agent in goat brain, from Dr R. L. Chandler (ARC, Compton, Berkshire).

 


 

Wednesday, February 16, 2011

 

IN CONFIDENCE SCRAPIE TRANSMISSION TO CHIMPANZEES

 

IN CONFIDENCE

 

Wednesday, February 16, 2011 IN CONFIDENCE SCRAPIE TRANSMISSION TO CHIMPANZEES

 

IN CONFIDENCE

 

reference...

 

RB3.20

 

TRANSMISSION TO CHIMPANZEES

 

1. Kuru and CJD have been successfully transmitted to chimpanzees but scrapie and TME have not.

 

2. We cannot say that scrapie will not transmit to chimpanzees. There are several scrapie strains and I am not aware that all have been tried (that would have to be from mouse passaged material). Nor has a wide enough range of field isolates subsequently strain typed in mice been inoculated by the appropriate routes (i/c, ilp and i/v) :

 

3. I believe the proposed experiment to determine transmissibility, if conducted, would only show the susceptibility or resistance of the chimpanzee to infection/disease by the routes used and the result could not be interpreted for the predictability of the susceptibility for man. Proposals for prolonged oral exposure of chimpanzees to milk from cattle were suggested a long while ago and rejected.

 

4. In view of Dr Gibbs' probable use of chimpazees Mr Wells' comments (enclosed) are pertinent. I have yet to receive a direct communication from Dr Schellekers but before any collaboration or provision of material we should identify the Gibbs' proposals and objectives.

 

5. A positive result from a chimpanzee challenged severely would likely create alarm in some circles even if the result could not be interpreted for man. I have a view that all these agents could be transmitted provided a large enough dose by appropriate routes was given and the animals kept long enough. Until the mechanisms of the species barrier are more clearly understood it might be best to retain that hypothesis.

 

6. A negative result would take a lifetime to determine but that would be a shorter period than might be available for human exposure and it would still not answer the question regarding mans' susceptibility. In the meantime no doubt the negativity would be used defensively. It would however be counterproductive if the experiment finally became positive. We may learn more about public reactions following next Monday' s meeting.

 

R. Bradley

 

23 September 1990

 

CVO (+Mr Wells' comments)

 

Dr T W A Little

 

Dr B J Shreeve

 

90/9.23/1.1.

 


 

IN CONFIDENCE CHIMPANZEES

 

CODE 18-77 Reference RB3.46

 

Some further information that may assist in decision making has been gained by discussion with Dr Rosalind Ridley.

 

She says that careful study of Gajdusek's work shows no increased susceptibility of chimpanzees over New World Monkeys such as Squirrel Monkeys. She does not think it would tell you anything about the susceptibility to man. Also Gajdusek did not, she believes, challenge chimpanzees with scrapie as severely as we did pigs and we know little of that source of scrapie. Comparisons would be difficult. She also would not expect the Home Office to sanction such experiments here unless there was a very clear and important objective that would be important for human health protection. She doubted such a case could be made. If this is the case she thought it would be unethical to do an experiment abroad because we could not do it in our own country.

 

Retrospectively she feels they should have put up more marmosets than they did. They all remain healthy. They would normally regard the transmission as negative if no disease resulted in five years.

 

We are not being asked for a decision but I think that before we made one we should gain as much knowledge as we can. If we decided to proceed we would have to bear any criticisms for many years if there was an adverse view by scientists or­media. This should not be undertaken lightly. There is already some adverse comment here, I gather, on the pig experiment though that will subside.

 

The Gibbs' (as' distinct from Schellekers') study is somewhat different. We are merely supplying material for comparative studies in a laboratory with the greatest experience of human SEs in the world and it has been sanctioned by USDA (though we do not know for certain yet if chimpanzees specifically will be used). This would keep it at a lower profile than if we conducted such an experiment in the UK or Europe.

 

I consider we must have very powerful and defendable objectives to go beyond Gibbs' proposed experiments and should not initiate others just because an offer has been made.

 

Scientists have a responsibility to seek other methods of investigative research other than animal experimentation. At present no objective has convinced me we need to do research using Chimpanzees - a species in need of protection. Resisting such proposals would enable us to communicate that information to the scientist and the public should the need arise. A line would have been drawn.

 

CVO cc Dr T Dr B W A Little Dr B J Shreeve

 

R Bradley

 

26 September 1990

 

90/9.26/3.2

 


 


 


 

SNIP...SEE FULL TEXT ;

 


 

Increased Atypical Scrapie Detections

 

Press reports indicate that increased surveillance is catching what otherwise would have been unreported findings of atypical scrapie in sheep. In 2009, five new cases have been reported in Quebec, Ontario, Alberta, and Saskatchewan. With the exception of Quebec, all cases have been diagnosed as being the atypical form found in older animals. Canada encourages producers to join its voluntary surveillance program in order to gain scrapie-free status. The World Animal Health will not classify Canada as scrapie-free until no new cases are reported for seven years. The Canadian Sheep Federation is calling on the government to fund a wider surveillance program in order to establish the level of prevalence prior to setting an eradication date. Besides long-term testing, industry is calling for a compensation program for farmers who report unusual deaths in their flocks.

 


 

J Vet Diagn Invest 21:454-463 (2009)

 

Nor98 scrapie identified in the United States

 

Christie M. Loiacono,' Bruce V. Thomsen, S. Mark Hall, Matti Kiupe!, Diane Sutton, Katherine O'Rourke, Bradd Barr, Lucy Anthenill, Deiwyn Keane

 

Abstract.

 

A distinct strain of scrapic identified in sheep of Norway in 1998 has since been identified in numerous countries throughout Europe. The disease is known as Nor98 or Not-98-like scrapic. among other names. Distinctions between classic scrapie and Nor98 scrapie are made based on histopathologv and immunodiagnostic results. There are also differences in the epidemiology, typical signalment, and likelihood of clinical signs being observed. In addition, sheep that have genotypes associated with resistance to classic scrapie are not spared from Nor98 disease. The various differences between classic and Nor98 scrapie have been consistently reported in the vast majority of cases described across Europe. The current study describes in detail the patholo gic changes and diagnostic results of the first 6 cases of' Nor98 scrapic disease diagnosed in sheep of the United States.

 

Key words: Hisiopathology: Nor98: PrP imniunolabeling; scrapie: sheep.

 

snip...

 

Results

 

Case I The first case identified as consistent with Nor98 scrapie had nonclassic PrP distribution in brain tissue, no PrPSC in lymph tissue, and nonclassic migration of protein bands on a Western blot test. The animal was an aged, mottled-faced ewe that was traced back to a commercial flock in Wyoming. ...

 

Case 2 The second case was a clinically normal 8-year-old Suffolk ewe that had been in a quarantined flock for 5 years at a USDA facility in Iowa.

 

Case 3 A 16-year-old, white-faced, cross-bred wether was born to a black-faced ewe. He lived his entire life as a pet on a farm in California.

 

Case 4 The fourth case of Nor98 scrapie was identified in an approximately 8-year-old Dorset ewe that was born into a flock of approximately 20 ewes in Indiana.

 

Case 5 The fifth case was a clinically normal, approximately 3-year-old, white-faced, cross-bred ewe from an approximately 400 head commercial flock in Minnesota.

 

Case 6 The sixth case of Nor98 scrapie was identified in a 4-year-old, white-faced ewe that was purchased and added to a commercial flock in Pennsylvania

 

snip...

 

see full text ;

 


 

Scrapie Nor-98 like case in California FY 2011 AS of December 31, 2010.

 

Scrapie cases in goats FY 2002 - 2011 AS of December 31, 2010 Total goat cases = 21 Scrapie cases, 0 Nor-98 like Scrapie cases (21 field cases, 0 RSSS cases)

 

Last herd with infected goats disignated in FY 2008 Michigan 8 cases

 


 

UPDATE PLEASE NOTE ;

 

AS of June 30, 2011,

 

snip...

 

INCLUDING 10 POSITIVE GOATS FROM THE SAME HERD (FIGURE 7).

 

snip...

 

see updated APHIS scrapie report ;

 


 

PAGE 25 Transmission Studies Mule deer transmissions of CWD were by intracerebral inoculation and compared with natural cases resulted in a more rapidly progressive clinical disease with repeated episodes of synocopy ending in coma. One control animal became affected, it is believed through contamination of inoculam (?saline). Further CWD transmissions were carried out by Dick Marsh into ferret, mink and squirrel monkey. Transmission occurred in all of these species with the shortest incubation period in the ferret...

 


 

Clearly, it is premature to draw firm conclusions about CWD passing naturally into humans, cattle and sheep, but the present results suggest that CWD transmissions to humans would be as limited by PrP incompatibility as transmissions of BSE or sheep scrapie to humans. Although there is no evidence that sheep scrapie has affected humans, it is likely that BSE has caused variant CJD in 74 people (definite and probable variant CJD cases to date according to the UK CJD Surveillance Unit). Given the presumably large number of people exposed to BSE infectivity, the susceptibility of humans may still be very low compared with cattle, which would be consistent with the relatively inefficient conversion of human PrP-sen by PrPBSE. Nonetheless, since humans have apparently been infected by BSE, it would seem prudent to take reasonable measures to limit exposure of humans (as well as sheep and cattle) to CWD infectivity as has been recommended for other animal TSEs.

 

snip...

 


 

and why do we not want to do TSE transmission studies on chimpanzees $

 

snip...

 

5. A positive result from a chimpanzee challenged severly would likely create alarm in some circles even if the result could not be interpreted for man. I have a view that all these agents could be transmitted provided a large enough dose by appropriate routes was given and the animals kept long enough. Until the mechanisms of the species barrier are more clearly understood it might be best to retain that hypothesis.

 

snip...

 

R. BRADLEY

 


 

1992

 

IN CONFIDENCE

 

BSE - ATYPICAL LESION DISTRIBUTION (RBSE 92-21367)

 


 

1992

 

NEW BRAIN DISORDER

 

3. WHAT ABOUT REPORTS OF NEW FORM OF BSE ?

 

THE VETERINARY RECORD HAS PUBLISHED AN ARTICLE ON A NEW BRAIN DISORDER OF CATTLE DISCOVERED THROUGH OUR CONTROL MEASURES FOR BSE. ALTHOUGH IT PRESENTS SIMILAR CLINICAL SIGNS TO BSE THERE ARE MAJOR DIFFERENCES IN HISTOPATHOLOGY AND INCUBATION PERIODS BETWEEN THE TWO. MUST EMPHASISE THAT THIS IS _NOT_ BSE.

 

4. IS THIS NEW BRAIN DISORDER A THREAT ?

 

WE DO NOT EVEN KNOW WHETHER THE AGENT OF THIS DISEASE IS TRANSMISSIBLE. IN ANY CASE, CASES SO FAR IDENTIFIED HAD SHOWN SIMILAR SYMPTOMS TO THOSE OF BSE, AND THEREFORE HAVE BEEN SLAUGHTERED AND INCINERATED, SO THAT IF A TRANSMISSIBLE AGENT WERE INVOLVED IT WOULD HAVE BEEN ELIMINATED. ...

 


 

Tuesday, November 17, 2009

 

SEAC NEW RESULTS ON IDIOPATHIC BRAINSTEM NEURONAL CHROMATOLYSIS (IBNC) FROM THE VETERINARY LABORATORIES AGENCY (VLA) SEAC 103/1

 


 

NEW RESULTS ON IDIOPATHIC BRAINSTEM NEURONAL CHROMATOLYSIS

 

"All of the 15 cattle tested showed that the brains had abnormally accumulated PrP"

 

2009

 


 

''THE LINE TO TAKE'' ON IBNC $$$ 1995 $$$

 

1995

 

page 9 of 14 ;

 

30. The Committee noted that the results were unusual. the questioned whether there could be coincidental BSE infection or contamination with scrapie. Dr. Tyrell noted that the feeling of the committee was that this did not represent a new agent but it was important to be prepared to say something publicly about these findings. A suggested line to take was that these were scientifically unpublishable results but in line with the policy of openness they would be made publicly available and further work done to test their validity. Since the BSE precautions were applied to IBNC cases, human health was protected. Further investigations should be carried out on isolations from brains of IBNC cases with removal of the brain and subsequent handling under strict conditions to avoid the risk of any contamination.

 

31. Mr. Bradley informed the Committee that the CVO had informed the CMO about the IBNC results and the transmission from retina and he, like the Committee was satisfied that the controls already in place or proposed were adequate. ... snip... see full text

 


 


 

IN CONFIDENCE

 

BSE ATYPICAL LESION DISTRIBUTION

 


 


 

 -------- Original Message --------

 

 Subject: DEFRA INVESTIGATES AN UNUSUAL SCRAPIE CASE (similar to exp. BSE in sheep)

 

Date: Wed, 7 Apr 2004 08:56:36 -0500

 

From: "Terry S. Singeltary Sr."

 

Reply-To: Bovine Spongiform Encephalopathy

 

To: BSE-L@uni-karlsruhe.de

 

 ######## Bovine Spongiform Encephalopathy #########

 

 Date: April 07, 2004 Time: 13:45

 

 DEFRA INVESTIGATES AN UNUSUAL SCRAPIE CASE

 

 The Veterinary Laboratories Agency (VLA) have informed Defra, the Devolved Administrations and the Food Standards Agency of a type of scrapie not previously seen in the UK.

 

 The VLA and other European laboratories with expertise in scrapie-like diseases have now applied several rapid diagnostic methods to tissue samples from a sheep with suspected scrapie. Some of the methods have indicated that the case does not appear to resemble previously recognised cases of scrapie and, although there were differences, it had some characteristics similar to experimental BSE in sheep and also to an experimental strain of sheep scrapie. More importantly, though, microscopic analysis of brain material showed that the case neither resembled previously recognised types of scrapie or experimental BSE in sheep.

 

 A meeting of the scientific experts who performed these analyses, held on the 30th March, concluded that this case could not be considered to be BSE in sheep, although it does not behave like known types of scrapie either. Further investigation will be needed before more can be said about how this unusual result should be described.

 

 Defra's Chief Scientific Adviser, Professor Howard Dalton, said "The UK, and especially the VLA, have played an important part in improving the diagnostic methods available for identifying TSEs in sheep. As we continue to assess more samples with these improved methods it is likely that we will continue to find samples, such as this, which fall outside our current knowledge of the disease. Defra, as it does with all research, will continue to consult scientific experts to ensure that we are investigating these cases using the best available techniques and methods."

 

 The National Scrapie Plan remains unaffected by this new result and SEAC will be consulted in the near future.

 

 Notes to editors

 

 1. Scrapie is a fatal neurological sheep disease belonging to a group of diseases called transmissible spongiform encephalopathies (TSEs), including BSE in cattle and CJD in humans. It has been present in the national flock for over 250 years. It is not considered to be transmissible to humans.

 

 2. There is a theoretical risk that BSE could be present in sheep, masked by scrapie, but it has not been found naturally occurring in sheep.

 

 3. There is as yet no definitive diagnostic method that can rapidly distinguish between different TSEs for example scrapie from BSE. Consequently, from time to time the scrapie surveillance programmes in EU member states throw up unusual results that merit further investigations (Defra press release 371/03 refers http://www.defra.gov.uk/news/2003/030911a.htm)

 

 4. The VLA have applied several different methods to the sample to compare it to a wide range of previously detected scrapie cases, experimental BSE in sheep and an experimental strain of scrapie, termed CH1461. Two main methods have been used in this analysis:-

 

 a. Western blot (WB) This involves taking a sample of the brain and treating it with an enzyme proteinase k to destroy the normal prion protein (PrPC). The diseased form of the protein (PrPSc) is able to withstand this treatment and is then separated from other cellular material on a gel. A blot is taken of the gel and the PrPSc is visualised using specific antibodies.

 

 b. Immunohistochemistry (IHC) This involves taking thin slices of the brain, and by using special (antibody) markers to detect the PrPSc it is possible to see disease specific patterns of PrPSc distribution in the brain under a microscope. The Western blot method found that the sample did not appear to resemble previously recognised cases of scrapie and, although there were some differences, some characteristics were similar to experimental BSE in sheep and also the experimental strain of sheep scrapie, CH1461. IHC found that it neither resembled previously recognised types of scrapie or experimental BSE in sheep

 

 5. The tissue sample has now been analysed using a total of 5 different diagnostic methods claiming to be able to differentiate between scrapie and experimental BSE in sheep. Two were performed at the VLA and three were performed in other European laboratories.

 

 6. The VLA is the European Reference Laboratory for TSEs and is responsible for co-ordinating such investigations into unusual cases. Their findings will be considered by the European Food Safety Authority's committee of TSE experts and in the UK by the Spongiform Encephalopathy Advisory Committee (SEAC).

 

 7. The genotype of the suspect sheep was ARQ/ARQ which is known to be susceptible to some strains of scrapie and, in experiments, to BSE. Background information on scrapie, scrapie genotyping, and the National Scrapie Plan is published on the Defra internet at www.defra.gov.uk/nsp.

 

 8. For information and advice on BSE in sheep from the FSA please consult their web site at www.foodstandards.gov.uk

 

 Public enquiries 08459 335577; Press notices are available on our website www.defra.gov.uk Defra's aim is sustainable development

 

 End

 

 Nobel House 17 Smith Square London SW1P 3JR Website www.defra.gov.uk

 


 

 TSS

 


 

 TSE in Sheep Contingency Planning Assessment of Risk due to BSE Infectivity from Disposal of Sheep A report for DEFRA November 2001

 

 Management Summary It has been recognised for a considerable time that sheep in the United Kingdom may have been infected with BSE. To date no evidence has been found to demonstrate that the national flock is actually infected with the disease. DEFRA have prepared a draft contingency plan in the event that BSE were to be identified in UK sheep. The worst case scenario under this plan is the disposal of the entire UK flock, some 40 million sheep and lambs. This study has estimated the potential exposure of the UK population to BSE infectivity present in sheep in the event that this plan had to be put into effect.

 


 

 but who would have guessed that such an important experiment/study would have gotton so screwed up, by not being able to tell a sheep brain from a cow brain;

 

© DEFRA 2002 Item 3- Scrapie Brain pool experiments- Update on current position and audits of samples 3.1 Members were updated on experiments conducted at the Institute of Animal Health (IAH) to examine a pool of scrapie brains collected in the early 1990 s for evidence of BSE. SEAC had previously recommended that the material should be examined by DNA analysis to assess whether the pooled brain material may have been contaminated with bovine tissue. The Laboratory of the Government Chemist (LGC) had been asked to perform the work. Their results were completely unexpected as the analysis detected only bovine material in the sample. SEAC had intended to meet on the 19 October to Agreed version consider the experiment in detail. However, in view of the result, the meeting was cancelled.

 


 

 Executive Summary An audit of the sample handling procedures at IAH-E was carried out on 24 October 2001 at the request of the Department of the Environment, Food and Rural Affairs (DEFRA), by a team of two UKAS auditors. The scope of the audit was limited to the traceability of cow and sheep brain samples used in several experiments relating to transmissible spongiform encephalopathy (TSE) agents. In particular, the team focused on the audit trail of samples that had been sent to LGC, Teddington, the audit trail of brains collected in 1990/92 by Veterinary Investigation Centres and the audit trail for archived material held by IAH-E. In addition the audit team evaluated the IAH-E procedures against the specific requirements for sampling handling of international standard, ISO 17025 and identified opportunities for improvement. The audit established that there was no formal documented quality system covering this work at IAH-E and that record keeping was inadequate to give confidence in the chain of custody of samples used in the various rendering, genotyping and strain typing experiments audited. It was not possible to establish clear traceability between the samples that had been used in the individual experiments carried out by IAH-E or IAH-C with those analysed at LGC or with those that had been collected in 1990/92. The sample handling procedures covered by this audit at IAH-E did not meet the requirements of ISO 17025.

 


 

 explaining the brain mixup blunder;

 

 An Investigation of the Substitution of Scrapie Brain Pool Samples A report for DEFRA November 2001

 

 Risk Solutions Page 19 Why did the experimenters not notice that they were working with cow brains not sheep brains? The simple answer is because for the most part they were working with brain pool macerate (minced brain material) not brains. It is not credible that staff collecting brains at VICs would have uniformly supplied cow brains or cow brain parts in mistake for sheep. We have interviewed staff at VICs and we understand from the VLA that records do not support the possibility that significant numbers of cow brains were sent to PDM in place of sheep brains. It is also very unlikely that the people preparing the scrapie brain pool would not have noticed if they were for the most part handling cow brains or cow brain parts in place of sheep brains. We cannot rule out the possibility that some cow brain material entered the brain pool at this stage but it is not feasible that the majority of the material was bovine. The substitution, if substitution occurred, must have involved brain pool macerate or rendered products. Why can t the results of the experiments tell us what material was used? The experiments had a number of features that make the results of the mouse bioassay difficult to interpret unambiguously and lead to the possibility that substitution of the samples would be difficult to detect by examining the results of the experiments: 1. The original experiments were not designed to determine whether BSE was present in sheep. Reasonable efforts were taken to ensure that the brain pool remained free from D5055 02 Issue 1 Risk Solutions Page 20 contamination during preparation but the level of control applied during the earlier experiments (272R and 372R) was not to the standard applied later. 2. Mouse bioassay as a method of diagnosing TSEs is not based on a full understanding of biochemical and physical processes. It is an empirical technique that has been widely applied, for example to show v-CJD is similar to BSE and different from scrapie. It is a complex process and the results need to be interpreted by experts. It can take several years to generate a firm result. The principal data collected in the experiments are lesion profiles (patterns of lesions in the mice brains) and incubation period (time from injection of mice to onset of clinical symptoms. The type of TSE is identified by comparing the results with those of known provenance. There is no good agreed test of sameness of lesion profile , so in marginal cases we are reduced to using subjective observations of the form somewhat similar and interpretation is difficult. The incubation times in principle give a more objective signal, but the effect of concentration has to be controlled. The mouse bioassay data that we understand has been collected and analysed at each stage of the experiments is summarised in Table 4.1. Several features of these experiments are not commonly encountered in mouse bioassay of TSEs and this makes determining the origin of the original material from the experimental results extremely difficult. They include: a. Mouse bioassay is generally carried out on individual brains; experience of working with brain pools is very limited. b. The BBP exhibited a low titre of infectivity, which can confound interpretation of results. c. The BBP comprised bovine brains with the hindbrains removed. By contrast most of the BSE strain typing has been carried out on the hindbrains, which may give a different pattern of results. d. The 272R titrations used a different strain of mice than the 372R titrations, so direct comparison of the resulting lesion profiles cannot be made. e. The 246 experiments used brain pool which was in an unsatisfactorily autolysed state. f. The strain typing data collected (incubation time and lesion profiles) are very sparse. Judging the sameness or difference of samples is a less challenging task for strain typing than identifying a strain and it may be possible to compare data from the 246 experiments with both the 272R and 372R experiments to determine whether the samples are similar or clearly different. However, the data are sparse and the result is unlikely to be clear cut. Much of this work is currently unpublished.

 


 

 RESPONSE TO THE UKAS REPORT FROM THE INSTITUTE FOR ANIMAL HEALTH

 

 The Institute is concerned, therefore, that the authors of this UKAS report may have based their findings on an unrepresentative and limited examination of procedures in place at IAH-E.

 


 


 


 

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

 

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

 

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 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?

 


 

***however in 1 C-type challenged animal, Prion 2015 Poster Abstracts S67 PrPsc was not detected using rapid tests for BSE.

 

***Subsequent testing resulted in the detection of pathologic lesion in unusual brain location and PrPsc detection by PMCA only.

 

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

 

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

 


 

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...

 


 

Evidence That Transmissible Mink Encephalopathy Results from Feeding Infected Cattle Over the next 8-10 weeks, approximately 40% of all the adult mink on the farm died from TME.

 

snip...

 

The rancher was a ''dead stock'' feeder using mostly (>95%) downer or dead dairy cattle...

 


 


 


 

In Confidence - Perceptions of unconventional slow virus diseases of animals in the USA - APRIL-MAY 1989 - G A H Wells

 

3. Prof. A. Robertson gave a brief account of BSE. The US approach was to accord it a very low profile indeed. Dr. A Thiermann showed the picture in the ''Independent'' with cattle being incinerated and thought this was a fanatical incident to be avoided in the US at all costs. ...

 


 


 

98 | Veterinary Record | January 24, 2015

 

EDITORIAL

 

Scrapie: a particularly persistent pathogen

 

Cristina Acín

 

Resistant prions in the environment have been the sword of Damocles for scrapie control and eradication. Attempts to establish which physical and chemical agents could be applied to inactivate or moderate scrapie infectivity were initiated in the 1960s and 1970s,with the first study of this type focusing on the effect of heat treatment in reducing prion infectivity (Hunter and Millson 1964). Nowadays, most of the chemical procedures that aim to inactivate the prion protein are based on the method developed by Kimberlin and collaborators (1983). This procedure consists of treatment with 20,000 parts per million free chlorine solution, for a minimum of one hour, of all surfaces that need to be sterilised (in laboratories, lambing pens, slaughterhouses, and so on). Despite this, veterinarians and farmers may still ask a range of questions, such as ‘Is there an official procedure published somewhere?’ and ‘Is there an international organisation which recommends and defines the exact method of scrapie decontamination that must be applied?’

 

From a European perspective, it is difficult to find a treatment that could be applied, especially in relation to the disinfection of surfaces in lambing pens of affected flocks. A 999/2001 EU regulation on controlling spongiform encephalopathies (European Parliament and Council 2001) did not specify a particular decontamination measure to be used when an outbreak of scrapie is diagnosed. There is only a brief recommendation in Annex VII concerning the control and eradication of transmissible spongiform encephalopathies (TSE s).

 

Chapter B of the regulation explains the measures that must be applied if new caprine animals are to be introduced to a holding where a scrapie outbreak has previously been diagnosed. In that case, the statement indicates that caprine animals can be introduced ‘provided that a cleaning and disinfection of all animal housing on the premises has been carried out following destocking’.

 

Issues around cleaning and disinfection are common in prion prevention recommendations, but relevant authorities, veterinarians and farmers may have difficulties in finding the specific protocol which applies. The European Food and Safety Authority (EFSA ) published a detailed report about the efficacy of certain biocides, such as sodium hydroxide, sodium hypochlorite, guanidine and even a formulation of copper or iron metal ions in combination with hydrogen peroxide, against prions (EFSA 2009). The report was based on scientific evidence (Fichet and others 2004, Lemmer and others 2004, Gao and others 2006, Solassol and others 2006) but unfortunately the decontamination measures were not assessed under outbreak conditions.

 

The EFSA Panel on Biological Hazards recently published its conclusions on the scrapie situation in the EU after 10 years of monitoring and control of the disease in sheep and goats (EFSA 2014), and one of the most interesting findings was the Icelandic experience regarding the effect of disinfection in scrapie control. The Icelandic plan consisted of: culling scrapie-affected sheep or the whole flock in newly diagnosed outbreaks; deep cleaning and disinfection of stables, sheds, barns and equipment with high pressure washing followed by cleaning with 500 parts per million of hypochlorite; drying and treatment with 300 ppm of iodophor; and restocking was not permitted for at least two years. Even when all of these measures were implemented, scrapie recurred on several farms, indicating that the infectious agent survived for years in the environment, even as many as 16 years after restocking (Georgsson and others 2006).

 

In the rest of the countries considered in the EFSA (2014) report, recommendations for disinfection measures were not specifically defined at the government level. In the report, the only recommendation that is made for sheep is repopulation with sheep with scrapie-resistant genotypes. This reduces the risk of scrapie recurrence but it is difficult to know its effect on the infection.

 

Until the EFSA was established (in May 2003), scientific opinions about TSE s were provided by the Scientific Steering Committee (SSC) of the EC, whose advice regarding inactivation procedures focused on treating animal waste at high temperatures (150°C for three hours) and high pressure alkaline hydrolysis (SSC 2003). At the same time, the TSE Risk Management Subgroup of the Advisory Committee on Dangerous Pathogens (ACDP) in the UK published guidance on safe working and the prevention of TSE infection. Annex C of the ACDP report established that sodium hypochlorite was considered to be effective, but only if 20,000 ppm of available chlorine was present for at least one hour, which has practical limitations such as the release of chlorine gas, corrosion, incompatibility with formaldehyde, alcohols and acids, rapid inactivation of its active chemicals and the stability of dilutions (ACDP 2009).

 

In an international context, the World Organisation for Animal Health (OIE) does not recommend a specific disinfection protocol for prion agents in its Terrestrial Code or Manual. Chapter 4.13 of the Terrestrial Code, General recommendations on disinfection and disinsection (OIE 2014), focuses on foot-and-mouth disease virus, mycobacteria and Bacillus anthracis, but not on prion disinfection. Nevertheless, the last update published by the OIE on bovine spongiform encephalopathy (OIE 2012) indicates that few effective decontamination techniques are available to inactivate the agent on surfaces, and recommends the removal of all organic material and the use of sodium hydroxide, or a sodium hypochlorite solution containing 2 per cent available chlorine, for more than one hour at 20ºC.

 

The World Health Organization outlines guidelines for the control of TSE s, and also emphasises the importance of mechanically cleaning surfaces before disinfection with sodium hydroxide or sodium hypochlorite for one hour (WHO 1999).

 

Finally, the relevant agencies in both Canada and the USA suggest that the best treatments for surfaces potentially contaminated with prions are sodium hydroxide or sodium hypochlorite at 20,000 ppm. This is a 2 per cent solution, while most commercial household bleaches contain 5.25 per cent sodium hypochlorite. It is therefore recommended to dilute one part 5.25 per cent bleach with 1.5 parts water (CDC 2009, Canadian Food Inspection Agency 2013).

 

So what should we do about disinfection against prions? First, it is suggested that a single protocol be created by international authorities to homogenise inactivation procedures and enable their application in all scrapie-affected countries. Sodium hypochlorite with 20,000 ppm of available chlorine seems to be the procedure used in most countries, as noted in a paper summarised on p 99 of this issue of Veterinary Record (Hawkins and others 2015). But are we totally sure of its effectiveness as a preventive measure in a scrapie outbreak? Would an in-depth study of the recurrence of scrapie disease be needed?

 

What we can conclude is that, if we want to fight prion diseases, and specifically classical scrapie, we must focus on the accuracy of diagnosis, monitoring and surveillance; appropriate animal identification and control of movements; and, in the end, have homogeneous and suitable protocols to decontaminate and disinfect lambing barns, sheds and equipment available to veterinarians and farmers. Finally, further investigations into the resistance of prion proteins in the diversity of environmental surfaces are required.

 

References

 

snip...

 

98 | Veterinary Record | January 24, 2015

 


 

Persistence of ovine scrapie infectivity in a farm environment following cleaning and decontamination

 

Steve A. C. Hawkins, MIBiol, Pathology Department1, Hugh A. Simmons, BVSc MRCVS, MBA, MA Animal Services Unit1, Kevin C. Gough, BSc, PhD2 and Ben C. Maddison, BSc, PhD3 + Author Affiliations

 

1Animal and Plant Health Agency, Woodham Lane, New Haw, Addlestone, Surrey KT15 3NB, UK 2School of Veterinary Medicine and Science, The University of Nottingham, Sutton Bonington, Loughborough, Leicestershire LE12 5RD, UK 3ADAS UK, School of Veterinary Medicine and Science, The University of Nottingham, Sutton Bonington, Loughborough, Leicestershire LE12 5RD, UK E-mail for correspondence: ben.maddison@adas.co.uk Abstract Scrapie of sheep/goats and chronic wasting disease of deer/elk are contagious prion diseases where environmental reservoirs are directly implicated in the transmission of disease. In this study, the effectiveness of recommended scrapie farm decontamination regimens was evaluated by a sheep bioassay using buildings naturally contaminated with scrapie. Pens within a farm building were treated with either 20,000 parts per million free chorine solution for one hour or were treated with the same but were followed by painting and full re-galvanisation or replacement of metalwork within the pen. Scrapie susceptible lambs of the PRNP genotype VRQ/VRQ were reared within these pens and their scrapie status was monitored by recto-anal mucosa-associated lymphoid tissue. All animals became infected over an 18-month period, even in the pen that had been subject to the most stringent decontamination process. These data suggest that recommended current guidelines for the decontamination of farm buildings following outbreaks of scrapie do little to reduce the titre of infectious scrapie material and that environmental recontamination could also be an issue associated with these premises.

 

SNIP...

 

Discussion

 

Thorough pressure washing of a pen had no effect on the amount of bioavailable scrapie infectivity (pen B). The routine removal of prions from surfaces within a laboratory setting is treatment for a minimum of one hour with 20,000 ppm free chlorine, a method originally based on the use of brain macerates from infected rodents to evaluate the effectiveness of decontamination (Kimberlin and others 1983). Further studies have also investigated the effectiveness of hypochlorite disinfection of metal surfaces to simulate the decontamination of surgical devices within a hospital setting. Such treatments with hypochlorite solution were able to reduce infectivity by 5.5 logs to lower than the sensitivity of the bioassay used (Lemmer and others 2004). Analogous treatment of the pen surfaces did not effectively remove the levels of scrapie infectivity over that of the control pens, indicating that this method of decontamination is not effective within a farm setting. This may be due to the high level of biological matrix that is present upon surfaces within the farm environment, which may reduce the amount of free chlorine available to inactivate any infectious prion. Remarkably 1/5 sheep introduced into pen D had also became scrapie positive within nine months, with all animals in this pen being RAMALT positive by 18 months of age. Pen D was no further away from the control pen (pen A) than any of the other pens within this barn. Localised hot spots of infectivity may be present within scrapie-contaminated environments, but it is unlikely that pen D area had an amount of scrapie contamination that was significantly different than the other areas within this building. Similarly, there were no differences in how the biosecurity of pen D was maintained, or how this pen was ventilated compared with the other pens. This observation, perhaps, indicates the slower kinetics of disease uptake within this pen and is consistent with a more thorough prion removal and recontamination. These observations may also account for the presence of inadvertent scrapie cases within other studies, where despite stringent biosecurity, control animals have become scrapie positive during challenge studies using barns that also housed scrapie-affected animals (Ryder and others 2009). The bioassay data indicate that the exposure of the sheep to a farm environment after decontamination efforts thought to be effective in removing scrapie is sufficient for the animals to become infected with scrapie. The main exposure routes within this scenario are likely to be via the oral route, during feeding and drinking, and respiratory and conjunctival routes. It has been demonstrated that scrapie infectivity can be efficiently transmitted via the nasal route in sheep (Hamir and others 2008), as is the case for CWD in both murine models and in white-tailed deer (Denkers and others 2010, 2013). Recently, it has also been demonstrated that CWD prions presented as dust when bound to the soil mineral montmorillonite can be infectious via the nasal route (Nichols and others 2013). When considering pens C and D, the actual source of the infectious agent in the pens is not known, it is possible that biologically relevant levels of prion survive on surfaces during the decontamination regimen (pen C). With the use of galvanising and painting (pen D) covering and sealing the surface of the pen, it is possible that scrapie material recontaminated the pens by the movement of infectious prions contained within dusts originating from other parts of the barn that were not decontaminated or from other areas of the farm.

 

Given that scrapie prions are widespread on the surfaces of affected farms (Maddison and others 2010a), irrespective of the source of the infectious prions in the pens, this study clearly highlights the difficulties that are faced with the effective removal of environmentally associated scrapie infectivity. This is likely to be paralleled in CWD which shows strong similarities to scrapie in terms of both the dissemination of prions into the environment and the facile mode of disease transmission. These data further contribute to the understanding that prion diseases can be highly transmissible between susceptible individuals not just by direct contact but through highly stable environmental reservoirs that are refractory to decontamination.

 

The presence of these environmentally associated prions in farm buildings make the control of these diseases a considerable challenge, especially in animal species such as goats where there is lack of genetic resistance to scrapie and, therefore, no scope to re-stock farms with animals that are resistant to scrapie.

 

Scrapie Sheep Goats Transmissible spongiform encephalopathies (TSE) Accepted October 12, 2014. Published Online First 31 October 2014

 


 

Monday, November 3, 2014

 

Persistence of ovine scrapie infectivity in a farm environment following cleaning and decontamination

 


 

PPo3-22:

 

Detection of Environmentally Associated PrPSc on a Farm with Endemic Scrapie

 

Ben C. Maddison,1 Claire A. Baker,1 Helen C. Rees,1 Linda A. Terry,2 Leigh Thorne,2 Susan J. Belworthy2 and Kevin C. Gough3 1ADAS-UK LTD; Department of Biology; University of Leicester; Leicester, UK; 2Veterinary Laboratories Agency; Surry, KT UK; 3Department of Veterinary Medicine and Science; University of Nottingham; Sutton Bonington, Loughborough UK

 

Key words: scrapie, evironmental persistence, sPMCA

 

Ovine scrapie shows considerable horizontal transmission, yet the routes of transmission and specifically the role of fomites in transmission remain poorly defined. Here we present biochemical data demonstrating that on a scrapie-affected sheep farm, scrapie prion contamination is widespread. It was anticipated at the outset that if prions contaminate the environment that they would be there at extremely low levels, as such the most sensitive method available for the detection of PrPSc, serial Protein Misfolding Cyclic Amplification (sPMCA), was used in this study. We investigated the distribution of environmental scrapie prions by applying ovine sPMCA to samples taken from a range of surfaces that were accessible to animals and could be collected by use of a wetted foam swab. Prion was amplified by sPMCA from a number of these environmental swab samples including those taken from metal, plastic and wooden surfaces, both in the indoor and outdoor environment. At the time of sampling there had been no sheep contact with these areas for at least 20 days prior to sampling indicating that prions persist for at least this duration in the environment. These data implicate inanimate objects as environmental reservoirs of prion infectivity which are likely to contribute to disease transmission.

 


 

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BSE: TIME TO TAKE H.B. PARRY SERIOUSLY

 

If the scrapie agent is generated from ovine DNA and thence causes disease in other species, then perhaps, bearing in mind the possible role of scrapie in CJD of humans (Davinpour et al, 1985), scrapie and not BSE should be the notifiable disease. ...

 


 

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

 

*** Approximately 4,200 fawns, defined as deer under 1 year of age, were sampled from the eradication zone over the last year. The majority of fawns sampled were between the ages of 5 to 9 months, though some were as young as 1 month. Two of the six fawns with CWD detected were 5 to 6 months old. All six of the positive fawns were taken from the core area of the CWD eradication zone where the highest numbers of positive deer have been identified.

 

"This is the first intensive sampling for CWD in fawns anywhere," said Dr. Julie Langenberg, Department of Natural Resources wildlife veterinarian, "and we are trying to learn as much as we can from these data".

 


 

Saturday, February 04, 2012

 

Wisconsin 16 MONTH age limit on testing dead deer Game Farm CWD Testing Protocol Needs To Be Revised

 


 

Articles of Significant Interest Selected from This Issue by the Editors Next Section Prions in the Blood of Infected Hosts: Early and Persistent Prions circulate in the blood of prion-infected hosts, including humans with variant Creutzfeldt-Jakob disease. Determining the parameters of blood-borne prions during the long asymptomatic phase of disease characteristic of all prion diseases has been a long-standing problem in prion biology. Elder et. al (p. 7421–7424) have demonstrated amyloid formation, a biomarker for prions, in the blood of prion-infected rodent and cervid hosts as early as 15 minutes post-mucosal or -intravenous infection. This prionemia persists throughout the disease course, indicating a role for hematogenous prions throughout the preclinical stage of illness.

 


 

***Immediate and Ongoing Detection of Prions in the Blood of Hamsters and Deer following Oral, Nasal, or Blood Inoculations

 

Alan M. Eldera, Davin M. Hendersona, Amy V. Nallsa, Edward A. Hoovera, Anthony E. Kincaidb,c, Jason C. Bartzb and Candace K. Mathiasona aDepartment of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA bMedical Microbiology and Immunology, Creighton University, Omaha, Nebraska, USA cDepartment of Pharmacy Sciences, Creighton University, Omaha, Nebraska, USA S. Perlman, Editor + Author Affiliations

 


 

CREUTZFELDT JAKOB DISEASE SURVEILLANCE IN THE UNITED KINGDOM THIRD ANNUAL REPORT AUGUST 1994

 

Consumption of venison and veal was much less widespread among both cases and controls. For both of these meats there was evidence of a trend with increasing frequency of consumption being associated with increasing risk of CJD. (not nvCJD, but sporadic CJD...tss) These associations were largely unchanged when attention was restricted to pairs with data obtained from relatives. ...

 

Table 9 presents the results of an analysis of these data.

 

There is STRONG evidence of an association between ‘’regular’’ veal eating and risk of CJD (p = .0.01).

 

Individuals reported to eat veal on average at least once a year appear to be at 13 TIMES THE RISK of individuals who have never eaten veal.

 

There is, however, a very wide confidence interval around this estimate. There is no strong evidence that eating veal less than once per year is associated with increased risk of CJD (p = 0.51).

 

The association between venison eating and risk of CJD shows similar pattern, with regular venison eating associated with a 9 FOLD INCREASE IN RISK OF CJD (p = 0.04).

 

There is some evidence that risk of CJD INCREASES WITH INCREASING FREQUENCY OF LAMB EATING (p = 0.02).

 

The evidence for such an association between beef eating and CJD is weaker (p = 0.14). When only controls for whom a relative was interviewed are included, this evidence becomes a little STRONGER (p = 0.08).

 

snip...

 

It was found that when veal was included in the model with another exposure, the association between veal and CJD remained statistically significant (p = < 0.05 for all exposures), while the other exposures ceased to be statistically significant (p = > 0.05).

 

snip...

 

In conclusion, an analysis of dietary histories revealed statistical associations between various meats/animal products and INCREASED RISK OF CJD. When some account was taken of possible confounding, the association between VEAL EATING AND RISK OF CJD EMERGED AS THE STRONGEST OF THESE ASSOCIATIONS STATISTICALLY. ...

 

snip...

 

In the study in the USA, a range of foodstuffs were associated with an increased risk of CJD, including liver consumption which was associated with an apparent SIX-FOLD INCREASE IN THE RISK OF CJD. By comparing the data from 3 studies in relation to this particular dietary factor, the risk of liver consumption became non-significant with an odds ratio of 1.2 (PERSONAL COMMUNICATION, PROFESSOR A. HOFMAN. ERASMUS UNIVERSITY, ROTTERDAM). (???...TSS)

 

snip...see full report ;

 


 

CJD9/10022

 

October 1994

 

Mr R.N. Elmhirst Chairman British Deer Farmers Association Holly Lodge Spencers Lane BerksWell Coventry CV7 7BZ

 

Dear Mr Elmhirst,

 

CREUTZFELDT-JAKOB DISEASE (CJD) SURVEILLANCE UNIT REPORT

 

Thank you for your recent letter concerning the publication of the third annual report from the CJD Surveillance Unit. I am sorry that you are dissatisfied with the way in which this report was published.

 

The Surveillance Unit is a completely independant outside body and the Department of Health is committed to publishing their reports as soon as they become available. In the circumstances it is not the practice to circulate the report for comment since the findings of the report would not be amended. In future we can ensure that the British Deer Farmers Association receives a copy of the report in advance of publication.

 

The Chief Medical Officer has undertaken to keep the public fully informed of the results of any research in respect of CJD. This report was entirely the work of the unit and was produced completely independantly of the the Department.

 

The statistical results reqarding the consumption of venison was put into perspective in the body of the report and was not mentioned at all in the press release. Media attention regarding this report was low key but gave a realistic presentation of the statistical findings of the Unit. This approach to publication was successful in that consumption of venison was highlighted only once by the media ie. in the News at one television proqramme.

 

I believe that a further statement about the report, or indeed statistical links between CJD and consumption of venison, would increase, and quite possibly give damaging credence, to the whole issue. From the low key media reports of which I am aware it seems unlikely that venison consumption will suffer adversely, if at all.

 


 

CREUTZFELDT JAKOB DISEASE SURVEILLANCE IN THE UNITED KINGDOM THIRD ANNUAL REPORT AUGUST 1994

 

Consumption of venison and veal was much less widespread among both cases and controls. For both of these meats there was evidence of a trend with increasing frequency of consumption being associated with increasing risk of CJD. (not nvCJD, but sporadic CJD...tss) These associations were largely unchanged when attention was restricted to pairs with data obtained from relatives. ...

 

Table 9 presents the results of an analysis of these data.

 

There is STRONG evidence of an association between ‘’regular’’ veal eating and risk of CJD (p = .0.01).

 

Individuals reported to eat veal on average at least once a year appear to be at 13 TIMES THE RISK of individuals who have never eaten veal.

 

There is, however, a very wide confidence interval around this estimate. There is no strong evidence that eating veal less than once per year is associated with increased risk of CJD (p = 0.51).

 

The association between venison eating and risk of CJD shows similar pattern, with regular venison eating associated with a 9 FOLD INCREASE IN RISK OF CJD (p = 0.04).

 

There is some evidence that risk of CJD INCREASES WITH INCREASING FREQUENCY OF LAMB EATING (p = 0.02).

 

The evidence for such an association between beef eating and CJD is weaker (p = 0.14). When only controls for whom a relative was interviewed are included, this evidence becomes a little STRONGER (p = 0.08).

 

snip...

 

It was found that when veal was included in the model with another exposure, the association between veal and CJD remained statistically significant (p = < 0.05 for all exposures), while the other exposures ceased to be statistically significant (p = > 0.05).

 

snip...

 

In conclusion, an analysis of dietary histories revealed statistical associations between various meats/animal products and INCREASED RISK OF CJD. When some account was taken of possible confounding, the association between VEAL EATING AND RISK OF CJD EMERGED AS THE STRONGEST OF THESE ASSOCIATIONS STATISTICALLY. ...

 

snip...

 

In the study in the USA, a range of foodstuffs were associated with an increased risk of CJD, including liver consumption which was associated with an apparent SIX-FOLD INCREASE IN THE RISK OF CJD. By comparing the data from 3 studies in relation to this particular dietary factor, the risk of liver consumption became non-significant with an odds ratio of 1.2 (PERSONAL COMMUNICATION, PROFESSOR A. HOFMAN. ERASMUS UNIVERSITY, ROTTERDAM). (???...TSS)

 

snip...see full report ;

 


 

Friday, May 22, 2015

 

*** Chronic Wasting Disease and Program Updates - 2014 NEUSAHA Annual Meeting 12-14 May 2014 ***

 


 

Wednesday, July 29, 2015
 
*** Porcine Prion Protein Amyloid or mad pig disease PSE
 
 

 

Saturday, May 30, 2015

 

PRION 2015 ORAL AND POSTER CONGRESSIONAL ABSTRACTS

 


 


 

Comments on technical aspects of the risk assessment were then submitted to FSIS.

 

Comments were received from Food and Water Watch, Food Animal Concerns Trust (FACT), Farm Sanctuary, R-CALF USA, Linda A Detwiler, and Terry S. Singeltary.

 

This document provides itemized replies to the public comments received on the 2005 updated Harvard BSE risk assessment. Please bear the following points in mind:

 


 

Owens, Julie

 

From: Terry S. Singeltary Sr. [flounder9@verizon.net]

 

Sent: Monday, July 24, 2006 1:09 PM

 

To: FSIS RegulationsComments

 

Subject: [Docket No. FSIS-2006-0011] FSIS Harvard Risk Assessment of Bovine Spongiform Encephalopathy (BSE)

 

Page 1 of 98

 


 

FSIS, USDA, REPLY TO SINGELTARY

 


 

PRION 2015 ORAL AND POSTER CONGRESSIONAL ABSTRACTS

 

THANK YOU PRION 2015 TAYLOR & FRANCIS, Professor Chernoff, and Professor Aguzzi et al, for making these PRION 2015 Congressional Poster and Oral Abstracts available freely to the public. ...Terry S. Singeltary Sr.

 

O.05: Transmission of prions to primates after extended silent incubation periods: Implications for BSE and scrapie risk assessment in human populations

 

Emmanuel Comoy, Jacqueline Mikol, Val erie Durand, Sophie Luccantoni, Evelyne Correia, Nathalie Lescoutra, Capucine Dehen, and Jean-Philippe Deslys Atomic Energy Commission; Fontenay-aux-Roses, France

 

Prion diseases (PD) are the unique neurodegenerative proteinopathies reputed to be transmissible under field conditions since decades. The transmission of Bovine Spongiform Encephalopathy (BSE) to humans evidenced that an animal PD might be zoonotic under appropriate conditions. Contrarily, in the absence of obvious (epidemiological or experimental) elements supporting a transmission or genetic predispositions, PD, like the other proteinopathies, are reputed to occur spontaneously (atpical animal prion strains, sporadic CJD summing 80% of human prion cases). Non-human primate models provided the first evidences supporting the transmissibiity of human prion strains and the zoonotic potential of BSE. Among them, cynomolgus macaques brought major information for BSE risk assessment for human health (Chen, 2014), according to their phylogenetic proximity to humans and extended lifetime. We used this model to assess the zoonotic potential of other animal PD from bovine, ovine and cervid origins even after very long silent incubation periods. We recently observed the direct transmission of a natural classical scrapie isolate to macaque after a 10-year silent incubation period, with features similar to some reported for human cases of sporadic CJD, albeit requiring fourfold longe incubation than BSE. Scrapie, as recently evoked in humanized mice (Cassard, 2014), is the third potentially zoonotic PD (with BSE and L-type BSE), ***thus questioning the origin of human sporadic cases. We will present an updated panorama of our different transmission studies and discuss the implications of such extended incubation periods on risk assessment of animal PD for human health.

 

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

 

***thus questioning the origin of human sporadic cases...TSS

 

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

 


 

Saturday, May 30, 2015

 

PRION 2015 ORAL AND POSTER CONGRESSIONAL ABSTRACTS

 


 


 

 PRION 2015 CONFERENCE FT. COLLINS CWD RISK FACTORS TO HUMANS

 

*** LATE-BREAKING ABSTRACTS PRION 2015 CONFERENCE ***

 

O18

 

Zoonotic Potential of CWD Prions

 

Liuting Qing1, Ignazio Cali1,2, Jue Yuan1, Shenghai Huang3, Diane Kofskey1, Pierluigi Gambetti1, Wenquan Zou1, Qingzhong Kong1 1Case Western Reserve University, Cleveland, Ohio, USA, 2Second University of Naples, Naples, Italy, 3Encore Health Resources, Houston, Texas, USA

 

Chronic wasting disease (CWD) is a widespread and expanding prion disease in free-ranging and captive cervid species in North America. The zoonotic potential of CWD prions is a serious public health concern. Current literature generated with in vitro methods and in vivo animal models (transgenic mice, macaques and squirrel monkeys) reports conflicting results. The susceptibility of human CNS and peripheral organs to CWD prions remains largely unresolved. In our earlier bioassay experiments using several humanized transgenic mouse lines, we detected protease-resistant PrPSc in the spleen of two out of 140 mice that were intracerebrally inoculated with natural CWD isolates, but PrPSc was not detected in the brain of the same mice. Secondary passages with such PrPSc-positive CWD-inoculated humanized mouse spleen tissues led to efficient prion transmission with clear clinical and pathological signs in both humanized and cervidized transgenic mice. Furthermore, a recent bioassay with natural CWD isolates in a new humanized transgenic mouse line led to clinical prion infection in 2 out of 20 mice. These results indicate that the CWD prion has the potential to infect human CNS and peripheral lymphoid tissues and that there might be asymptomatic human carriers of CWD infection.

 

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

 

***These results indicate that the CWD prion has the potential to infect human CNS and peripheral lymphoid tissues and that there might be asymptomatic human carriers of CWD infection.***

 

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

 

P.105: RT-QuIC models trans-species prion transmission

 

Kristen Davenport, Davin Henderson, Candace Mathiason, and Edward Hoover Prion Research Center; Colorado State University; Fort Collins, CO USA

 

The propensity for trans-species prion transmission is related to the structural characteristics of the enciphering and heterologous PrP, but the exact mechanism remains mostly mysterious. Studies of the effects of primary or tertiary prion protein structures on trans-species prion transmission have relied primarily upon animal bioassays, making the influence of prion protein structure vs. host co-factors (e.g. cellular constituents, trafficking, and innate immune interactions) difficult to dissect. As an alternative strategy, we used real-time quakinginduced conversion (RT-QuIC) to investigate trans-species prion conversion.

 

To assess trans-species conversion in the RT-QuIC system, we compared chronic wasting disease (CWD) and bovine spongiform encephalopathy (BSE) prions, as well as feline CWD (fCWD) and feline spongiform encephalopathy (FSE). Each prion was seeded into each host recombinant PrP (full-length rPrP of white-tailed deer, bovine or feline). We demonstrated that fCWD is a more efficient seed for feline rPrP than for white-tailed deer rPrP, which suggests adaptation to the new host.

 

Conversely, FSE maintained sufficient BSE characteristics to more efficiently convert bovine rPrP than feline rPrP. Additionally, human rPrP was competent for conversion by CWD and fCWD. ***This insinuates that, at the level of protein:protein interactions, the barrier preventing transmission of CWD to humans is less robust than previously estimated.

 

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

 

***This insinuates that, at the level of protein:protein interactions, the barrier preventing transmission of CWD to humans is less robust than previously estimated.***

 

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

 


 

I strenuously once again urge the FDA and its industry constituents, to make it MANDATORY that all ruminant feed be banned to all ruminants, and this should include all cervids as soon as possible for the following reasons...

 

======

 

In the USA, under the Food and Drug Administrations BSE Feed Regulation (21 CFR 589.2000) most material (exceptions include milk, tallow, and gelatin) from deer and elk is prohibited for use in feed for ruminant animals. With regards to feed for non-ruminant animals, under FDA law, CWD positive deer may not be used for any animal feed or feed ingredients. For elk and deer considered at high risk for CWD, the FDA recommends that these animals do not enter the animal feed system.

 

***However, this recommendation is guidance and not a requirement by law.

 

======

 

31 Jan 2015 at 20:14 GMT

 

*** Ruminant feed ban for cervids in the United States? ***

 

Singeltary et al

 

31 Jan 2015 at 20:14 GMT

 


 

 

 

Terry S. Singeltary Sr.

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