Wednesday, October 24, 2018

Experimental Infection of Cattle With a Novel Prion Derived From Atypical H-Type Bovine Spongiform Encephalopathy

Experimental Infection of Cattle With a Novel Prion Derived From Atypical H-Type Bovine Spongiform Encephalopathy


Hiroyuki Okada, Kentaro Masujin, Kohtaro Miyazawa, ...


First Published July 21, 2017 


https://doi.org/10.1177/0300985817717769


Article information 


Abstract


H-type bovine spongiform encephalopathy (H-BSE) is an atypical form of BSE in cattle. During passaging of H-BSE in transgenic bovinized (TgBoPrP) mice, a novel phenotype of BSE, termed BSE-SW emerged and was characterized by a short incubation time and host weight loss. To investigate the biological and biochemical properties of the BSE-SW prion, a transmission study was conducted in cattle, which were inoculated intracerebrally with brain homogenate from BSE-SW–infected TgBoPrP mice. The disease incubation period was approximately 15 months. The animals showed characteristic neurological signs of dullness, and severe spongiform changes and a widespread, uniform distribution of disease-associated prion protein (PrPSc) were observed throughout the brain of infected cattle. Immunohistochemical PrPSc staining of the brain revealed the presence of intraglial accumulations and plaque-like deposits. No remarkable differences were identified in vacuolar lesion scores, topographical distribution patterns, and staining types of PrPSc in the brains of BSE-SW– vs H-BSE–infected cattle. PrPSc deposition was detected in the ganglia, vagus nerve, spinal nerve, cauda equina, adrenal medulla, and ocular muscle. Western blot analysis revealed that the specific biochemical properties of the BSE-SW prion, with an additional 10- to 12-kDa fragment, were well maintained after transmission. These findings indicated that the BSE-SW prion has biochemical properties distinct from those of H-BSE in cattle, although clinical and pathologic features of BSW-SW in cattle are indistinguishable from those of H-BSE. The results suggest that the 2 infectious agents, BSE-SW and H-BSE, are closely related strains.


snip...


Discussion


The present study aimed to characterize the pathologic and biochemical features of BSE-SW in cattle, a prion variant newly emerged from H-BSE after serial passages in bovinized mice,25 in comparison with H-BSE. The clinical signs in cattle infected with BSE-SW were consistent with those previously described for H-BSE–infected cattle22,30 and included difficulty in rising and dullness, without display of nervousness or hyperesthesia to acoustic or tactile stimuli. However, behavioral changes can vary depending on the experimental conditions.22,27 Despite the common clinical signs, the incubation period of BSE-SW in cattle (14.8 ± 1.5 months postinoculation [mpi]) was shorter than that of original H-BSE inoculum (18.7 ± 1.6 mpi),30 while the time of clinical onset—between 11.5 and 12.5 months after inoculation—was similar for both prions. The incubation period or clinical duration of the disease in cattle challenged with H-BSE can vary among experiments.1,17,22 Although the exact reasons for shorter incubation periods or clinical durations remain unknown, this may be due to differences in inoculum titers of the agents (Suppl. Fig. S3) or host/environmental factors rather than differences in inoculum strains.27 Alternatively, the BSE-SW prion may be more virulent than the H-BSE prion in cattle. The shortened incubation period in cattle was in accordance with that observed in BSE-SW– as compared to H-BSE–infected TgBoPrP mice.


Vacuolar lesion scores in the cattle infected with BSE-SW resembled those described for H-BSE–infected cattle.30 The PrPSc staining types were characterized by intraglial labeling in the white matter throughout the brain and spinal cord in addition to plaque-like deposits in the cerebral white matter, which was consistent with previous studies in cattle experimentally challenged with H-BSE.22,30 In addition, regional distribution patterns of PrPSc caused by BSE-SW were identical to those of H-BSE.30 Thus, on the basis of pathologic results, including vacuolar lesion scores, PrPSc neuroanatomical distribution patterns, and PrPSc staining types, BSE-SW shows more commonalities than differences with H-BSE in cattle.


The widespread PrPSc accumulation in extracerebral tissues detected by IHC as well as Western blotting may result from the centrifugal spreading of prions from the brain via nerve pathways during the clinical stage of the disease.1 However, extracerebral involvement of PrPSc in cattle infected with BSE-SW was smaller than that in animals infected with H-BSE and seemed to be influenced by the shorter clinical duration. No striking difference was identified in the topographical tropism of PrPSc between H-BSE and BSE-SW prion-infected cattle. The absence of PrPSc lymphotropism in cattle and wild-type mice infected with BSE-SW was in accordance with the results reported for H-BSE.


With regard to strain-specific molecular features, similar to H-BSE,9 BSE-SW was characterized by the presence of 2 cleaved forms of PrPres, PrPres 1 (N-terminally truncated) and PrPres 2 (C-terminally truncated), as shown by Western blotting. The characteristic multiple-banded patterns with an additional 10- to 12-kDa fragment analyzed with mAb SAF84 in TgBoPrP mice infected with BSE-SW were reproduced in cattle, indicating that both PrPres fragments of BSE-SW and uncleaved PrPres were consistently maintained after transmission into cattle. Usually, PrPres 1 is detectable using N-terminal–specific antibodies, such as P4 (bovine PrP epitope 101-WGQGGSH-107). However, the proteinase K cleavage site of PrPres 1 of BSE-SW in cattle, which was analyzed with mAbs P4, 6H4, and SAF84 (Suppl. Fig. S1), was distinct from that of H-BSE, indicating that PrPSc of BSE-SW has a different conformation than H-BSE.25 Interestingly, with mAb 6H4, bands from BSE-SW closely resembled those from C-BSE. However, glycoform patterns from BSE-SW were similar to those from H-BSE. The unique strain-specific molecular features of BSW-SW previously described in TgBoPrP mice,25 such as molecular weight, proteinase K cleavage sites, and glycoform profiles, were fully conserved after the transmission into cattle. The PrPres 1 of approximately 17 kDa from BSE-SW in TgBoPrP mice was more sensitive to guanidine hydrochloride treatment than that of H-BSE.25 The biochemical evidence supports the concept that changes in the conformational stability of PrPres 1 may contribute to PrPSc diversity. Therefore, changes in replication environment may play an active role in generating new PrPSc variants to fit the new environment.24 Artificial conditions, such as overexpression of PrP transgenes in TgBoPrP mice, most likely influence PrPSc diversity during serial transmission.


Traceback transmission is useful to maintain or alter strain-specific features of isolates before and after passage during cross-species transmission.21 However, inoculation of BSE-SW isolated from cattle back into TgBoPrP mice failed to produce the traceback phenomenon21 of the original H-BSE, even after further passages in TgBoPrP mice. In this study, back transmission of H-BSE from TgBoPrP mice into cattle was not carried out. However, the original H-BSE disease phenotype is expected to reemerge in cattle after transmission from TgBoPrP and/or wild-type mice infected with H-BSE owing to the traceback phenomenon.


In conclusion, no distinct differences in clinical and pathologic features were detected between BSE-SW and H-BSE in cattle, and biochemical properties of BSE-SW in cattle were well conserved from BSE-SW in TgBoPrP mice but distinct from those of H-BSE in cattle. The differences in molecular properties between BSW-SW and H-BSE did not influence the disease phenotype in cattle, suggesting that these 2 infectious agents are closely related strains. The fact that BSE-SW can transmit to cattle provides an important insight for devising control measures for atypical BSE. Further research is needed to prevent the spread of yet another form of atypical BSEs and for risk assessment and disease control measures of atypical BSEs. 


 http://journals.sagepub.com/doi/full/10.1177/0300985817717769


Acknowledgements


Keywords atypical bovine spongiform encephalopathy, back transmission, bovinized transgenic mouse, cattle, H-type, prion References 1. Balkema-Buschmann, A, Ziegler, U, McIntyre, L. Experimental challenge of cattle with German atypical bovine spongiform encephalopathy (BSE) isolates. J Toxicol Environ Health A. 2011;74(2–4):103–109. Google Scholar, Crossref, Medline 2. Baron, T, Bencsik, A, Biacabe, AG. Phenotypic similarity of transmissible mink encephalopathy in cattle and L-type bovine spongiform encephalopathy in a mouse model. Emerg Infect Dis. 2007;13(12):1887–1894. Google Scholar, Crossref, Medline, ISI 3. Baron, T, Biacabe, AG, Arsac, JN. Atypical transmissible spongiform encephalopathies (TSEs) in ruminants. Vaccine. 2007;25(30):5625–5630. Google Scholar, Crossref, Medline, ISI 4. Baron, T, Vulin, J, Biacabe, AG. Emergence of classical BSE strain properties during serial passages of H-BSE in wild-type mice. PLoS One. 2011;6(1): e15839. Google Scholar, Crossref, Medline, ISI 5. Baron, TG, Biacabe, AG, Bencsik, A. Transmission of new bovine prion to mice. Emerg Infect Dis. 2006;12(7):1125–1128. Google Scholar, Crossref, Medline, ISI 6. Bencsik, A, Leboidre, M, Debeer, S. Unique properties of the classical bovine spongiform encephalopathy strain and its emergence from H-type bovine spongiform encephalopathy substantiated by VM transmission studies. J Neuropathol Exp Neurol. 2013;72(3):211–218. Google Scholar, Crossref, Medline, ISI 7. Béringue, V, Bencsik, A, Le Dur, A. Isolation from cattle of a prion strain distinct from that causing bovine spongiform encephalopathy. PLoS Pathog. 2006;2(10):e112. Google Scholar, Crossref, Medline, ISI 8. Béringue, V, Vilotte, JL, Laude, H. Prion agent diversity and species barrier. Vet Res. 2008;39(4):47. Google Scholar, Crossref, Medline, ISI 9. Biacabe, AG, Jacobs, JG, Bencsik, A. H-type bovine spongiform encephalopathy: complex molecular features and similarities with human prion diseases. Prion. 2007;1(1):61–68. Google Scholar, Crossref, Medline, ISI 10. Biacabe, AG, Laplanche, JL, Ryder, S. Distinct molecular phenotypes in bovine prion diseases. EMBO Rep. 2004;5(1):110–115. Google Scholar, Crossref, Medline, ISI 11. Brown, P, McShane, LM, Zanusso, G. On the question of sporadic or atypical bovine spongiform encephalopathy and Creutzfeldt-Jakob disease. Emerg Infect Dis. 2006;12(12):1816–1821. Google Scholar, Crossref, Medline, ISI 12. Buschmann, A, Gretzschel, A, Biacabe, AG. Atypical BSE in Germany—proof of transmissibility and biochemical characterization. Vet Microbiol. 2006;117(2–4):103–116. Google Scholar, Crossref, Medline, ISI 13. Capobianco, R, Casalone, C, Suardi, S. Conversion of the BASE prion strain into the BSE strain: the origin of BSE? PLoS Pathog. 2007;3(3):e31. Google Scholar, Crossref, Medline, ISI 14. Casalone, C, Zanusso, G, Acutis, P. Identification of a second bovine amyloidotic spongiform encephalopathy: molecular similarities with sporadic Creutzfeldt-Jakob disease. Proc Natl Acad Sci U S A. 2004;101(9):3065–3070. Google Scholar, Crossref, Medline, ISI 15. Dudas, S, Yang, J, Graham, C. Molecular, biochemical and genetic characteristics of BSE in Canada. PLoS One. 2010;5(5):e10638. Google Scholar, Crossref, Medline, ISI 16. Greenlee, JJ, Smith, JD, West Greenlee, MH. Clinical and pathologic features of H-type bovine spongiform encephalopathy associated with E211 K prion protein polymorphism. PLoS One. 2012;7(6):e38678. Google Scholar, Crossref, Medline, ISI 17. Greenlee, MH, Smith, JD, Platt, EM. Changes in retinal function and morphology are early clinical signs of disease in cattle with bovine spongiform encephalopathy. PLoS One. 2015;10(3):e0119431. Google Scholar, Medline, ISI 18. Ishii, W, Matsuda, M, Nakamura, N. Phenol Congo red staining enhances the diagnostic value of abdominal fat aspiration biopsy in reactive AA amyloidosis secondary to rheumatoid arthritis. Intern Med. 2003;42(5):400–405. Google Scholar, Crossref, Medline, ISI 19. Jacobs, JG, Langeveld, JP, Biacabe, AG. Molecular discrimination of atypical bovine spongiform encephalopathy strains from a geographical region spanning a wide area in Europe. J Clin Microbiol. 2007;45(6):1821–1829. Google Scholar, Crossref, Medline, ISI 20. Kitamoto, T, Mohri, S, Ironside, JW. Follicular dendritic cell of the knock-in mouse provides a new bioassay for human prions. Biochem Biophys Res Commun. 2002;294(2):280–286. Google Scholar, Crossref, Medline, ISI 21. Kobayashi, A, Asano, M, Mohri, S. A traceback phenomenon can reveal the origin of prion infection. Neuropathology. 2009;29(5):619–624. Google Scholar, Crossref, Medline, ISI 22. Konold, T, Bone, GE, Clifford, D. Experimental H-type and L-type bovine spongiform encephalopathy in cattle: observation of two clinical syndromes and diagnostic challenges. BMC Vet Res. 2012;8:22. Google Scholar, Crossref, Medline, ISI 23. Konold, T, Phelan, LJ, Clifford, D. The pathological and molecular but not clinical phenotypes are maintained after second passage of experimental atypical bovine spongiform encephalopathy in cattle. BMC Vet Res. 2014;10:243. Google Scholar, Crossref, Medline, ISI 24. Makarava, N, Baskakov, IV. The evolution of transmissible prions: the role of deformed templating. PLoS Pathog. 2013;9(12):e1003759. Google Scholar, Crossref, Medline, ISI 25. Masujin, K, Okada, H, Miyazawa, K. Emergence of a novel bovine spongiform encephalopathy (BSE) prion from an atypical H-type BSE. Sci Rep. 2016;6:22753. Google Scholar, Crossref, Medline, ISI 26. Matsuura, Y, Ishikawa, Y, Somerville, RA. A rapid bioassay for classical and L-type bovine spongiform encephalopathies. Open J Vet Med. 2013;3(3):79–85. Google Scholar, Crossref 27. Moore, SJ, Greenlee, MHW, Smith, JD. A comparison of classical and H-type bovine spongiform encephalopathy associated with E211 K prion protein polymorphism in wild-type and EK211 cattle following intracranial inoculation. Front Vet Sci. 2016;3:78. Google Scholar, Crossref, Medline 28. Nicot, S, Baron, T. Strain-specific barriers against bovine prions in hamsters. J Virol. 2011;85(4):1906–1908. Google Scholar, Crossref, Medline, ISI 29. Okada, H, Iwamaru, Y, Fukuda, S. Detection of disease-associated prion protein in the optic nerve and the adrenal gland of cattle with bovine spongiform encephalopathy by using highly sensitive immunolabeling procedures. J Histochem Cytochem. 2012;60(4):290–300. Google Scholar, SAGE Journals, ISI 30. Okada, H, Iwamaru, Y, Imamura, M. Experimental H-type bovine spongiform encephalopathy characterized by plaques and glial- and stellate-type prion protein deposits. Vet Res. 2011;42:79. Google Scholar, Crossref, Medline, ISI 31. Okada, H, Iwamaru, Y, Yokoyama, T. Immunohistochemical detection of disease-associated prion protein in the peripheral nervous system in experimental H-type bovine spongiform encephalopathy. Vet Pathol. 2013;50(4):659–663. Google Scholar, SAGE Journals, ISI 32. Okada, H, Masujin, K, Iwamaru, Y. Experimental transmission of H-type bovine spongiform encephalopathy to bovinized transgenic mice. Vet Pathol. 2011;48(5):942–947. Google Scholar, SAGE Journals, ISI 33. Okada, H, Masujin, K, Miyazawa, K. Transmissibility of H-type bovine spongiform encephalopathy to hamster PrP transgenic mice. PLoS One. 2015;10(10):e0138977. Google Scholar, Crossref, Medline, ISI 34. Okada, H, Miyazawa, K, Masujin, K. Coexistence of two forms of disease-associated prion protein in extracerebral tissues of cattle infected with H-type bovine spongiform encephalopathy. J Vet Med Sci. 2016;78(7):1189–1193. Google Scholar, Crossref, Medline, ISI 35. Okada, H, Sato, Y, Sata, T. Antigen retrieval using sodium hydroxide for prion immunohistochemistry in bovine spongiform encephalopathy and scrapie. J Comp Pathol. 2011;144(4):251–256. Google Scholar, Crossref, Medline, ISI 36. Prusiner, SB . Molecular biology of prion diseases. Science. 1991;252(5012):1515–1522. Google Scholar, Crossref, Medline, ISI 37. Science Council of Japan . Guidelines for Proper Conduct of Animal Experiments Science Council of Japan. 6 1, 2006. http://wwwscjgojp/ja/info/kohyo/pdf/kohyo-20-k16-2epdf. Google Scholar 38. Scott, MR, Safar, J, Telling, G. Identification of a prion protein epitope modulating transmission of bovine spongiform encephalopathy prions to transgenic mice. Proc Natl Acad Sci U S A. 1997;94(26):14279–14284. Google Scholar, Crossref, Medline, ISI 39. Seuberlich, T, Gsponer, M, Drogemuller, C. Novel prion protein in BSE-affected Cattle, Switzerland. Emerg Infect Dis. 2012;18(1):158–159. Google Scholar, Crossref, Medline, ISI 40. Shimizu, Y, Kaku-Ushiki, Y, Iwamaru, Y. A novel anti-prion protein monoclonal antibody and its single-chain fragment variable derivative with ability to inhibit abnormal prion protein accumulation in cultured cells. Microbiol Immunol. 2010;54(2):112–121. Google Scholar, Crossref, Medline, ISI 41. Simmons, MM, Harris, P, Jeffrey, M. BSE in Great Britain: consistency of the neurohistopathological findings in two random annual samples of clinically suspect cases. Vet Rec. 1996;138(8):175–177. Google Scholar, Crossref, Medline, ISI 42. Torres, JM, Andréoletti, O, Lacroux, C. Classical bovine spongiform encephalopathy by transmission of H-type prion in homologous prion protein context. Emerg Infect Dis. 2011;17(9):1636–1644. Google Scholar, Crossref, Medline, ISI 43. Wilesmith, JW, Ryan, JB, Atkinson, MJ. Bovine spongiform encephalopathy: epidemiological studies on the origin. Vet Rec. 1991;128(9):199–203. Google Scholar, Crossref, Medline, ISI 44. Wilesmith, JW, Wells, GA, Cranwell, MP. Bovine spongiform encephalopathy: epidemiological studies. Vet Rec. 1988;123(25):638–644. Google Scholar, Medline, ISI



http://journals.sagepub.com/doi/abs/10.1177/0300985817717769?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%3dpubmed



***> Alternatively, the BSE-SW prion may be more virulent than the H-BSE prion in cattle. The shortened incubation period in cattle was in accordance with that observed in BSE-SW– as compared to H-BSE–infected TgBoPrP mice.



> BSE not caused by contaminated animal feed

LOL! that is the dumbest statement i have heard lately.

please see my comments and the latest and old science that refutes this very statement...

BSE not caused by contaminated animal feed

It will now be 11 years from the birth of the infected animal before Scotland can return to its previous bovine spongiform encephalopathy negligible risk status.

The discovery of a bovine spongiform encephalopathy (BSE) infected cow in Aberdeenshire is expected to have a “negligible” impact on exports, the Scottish rural affairs minister has said.

Mairi Gougeon told members of the Scottish Parliament it would now be 11 years from the birth of the animal infected with so-called mad cow disease before the country could return to its previous BSE negligible risk status.

Investigation The infected animal was found dead at a farm in the Huntly area of Aberdeenshire and routine testing picked up the disease.

A movement ban has been put in place at the farm as investigators try to determine the source of infection.

Speaking at Holyrood during Topical Questions, Ms Gougeon said early investigations have not identified any problem with animal feed, which has been a source of outbreaks in the past.

‘Heartbreaking’ Ms Gougeon said: “This could well be the tail end of the epidemic that we saw in the 1990s.”

Prior to the discovery of the latest case, Scotland had been BSE free since 2009, and the last recorded case of the disease in the UK was in Wales in 2015.

The farmer whose cow was found to have BSE has said he had taken pride in doing everything correctly and it was “heartbreaking” to be told the dead animal had the disease after routine testing.

Under control Scotland’s CVO Sheila Voas has said she believes the disease was not transmitted, and occurred spontaneously in the affected animal.

She said the case is isolated, under control and will not affect the food chain.



THURSDAY, OCTOBER 18, 2018 

Scotland Bovine Spongiform Encephalopathy (BSE) Mad Cow Disease has been confirmed on a farm in Aberdeenshire



> BSE not caused by contaminated animal feed


LOL! that is the dumbest statement i have heard lately.

i have read the same thing from the BSE Inquiry. but it's just not substantiated by facts. i believe it was all of the above, any and all tse circulated in the feed, from all species, and the bovine is one of them, proven to be so right here in the USA i.e. Richard Marsh et al.

what about those 300,000 or so mad cows at the height of the mad cow epidemic, the ruminant mammalian feed bad (or lack there of in the USA), but the UK, since that feed ban, time has shown those at the height of the BSE epidemic, and then the feed ban, those figures dropped dramatically. 

PLUS, with the recent findings that CWD tse prion in deer and elk, and scrapie in sheep and goats, will also transmit orally to PIGS, and the new outbreak of a new TSE Prion disease in a new species in a new part of the world, i.e. mad camel disease, and this is very disturbing. 


to start with;

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...
 
 
 


O3 Experimental studies on prion transmission barrier and TSE pathogenesis in large animals 

 
Rosa Bolea(1), Acín C(1)Marín B(1), Hedman C(1), Raksa H(1), Barrio T(1), Otero A(1), LópezPérez O(1), Monleón E(1),Martín-Burriel(1), Monzón M(1), Garza MC(1), Filali H(1),Pitarch JL(1), Garcés M(1), Betancor M(1), GuijarroIM(1), GarcíaM(1), Moreno B(1),Vargas A(1), Vidal E(2), Pumarola M(2), Castilla J(3), Andréoletti O(4), Espinosa JC(5), Torres JM(5), Badiola JJ(1). 

1Centro de Investigación en Encefalopatías y Enfermedades Transmisibles Emergentes, VeterinaryFaculty, Universidad de Zaragoza; Zaragoza,Spain.2 RTA, Centre de Recerca en Sanitat Animal (CReSA, IRTA-UAB) 3 4 INRA, ÉcoleVétérinaire, Toulouse, France.5CIC bioGUNE, Prion researchlab, Derio, Spain CISA- INIA, Valdeolmos, Madrid 28130, Spain. 

Experimental transmission of Transmissible Spongiform Encephalopathies (TSE) has been understood and related with several factors that could modify the natural development of these diseases. In fact, the behaviour of the natural disease does not match exactly in each animal, being modified by parameters such as the age at infection, the genotype, the breed or the causative strain. Moreover, different TSE strains can target different animal species or tissues, what complicate the prediction of its transmissibility when is tested in a different species of the origin source. The aim of the experimental studies in large animals is to homogenize all those factors, trying to minimize as much as possible variations between individuals. These effects can be flattened by experimental transmission in mice, in which a specific strain can be selected after several passages. With this objective, several experimental studies in large animals have been developed by the presenter research team. 

Classical scrapie agent has been inoculated in cow, with the aim of demonstrate the resistance or susceptibility of this species to the first well known TSE; Atypical scrapie has been inoculated in sheep (using several routes of infection), cow and pig, with the objective of evaluating the potential pathogenicity of this strain; Classical Bovine Spongiform Encephalopathy (BSE) has been inoculated in goats aiming to demonstrate if the genetic background of this species could protect against this strain; goat BSE and sheep BSE have been inoculated in goats and pigs respectively to evaluate the effect of species barrier; and finally atypical BSE has been inoculated in cattle to assess the transmissibility properties of this newly introduced strain. 

Once the experiments have been carried out on large animal species, a collection of samples from animals studied were inoculated in different types of tg mice overexpressing PrPcin order to study the infectivity of the tissues, and also were studied using PMCA. 

In summary, the parameters that have been controlled are the species, the strain, the route of inoculation, the time at infection, the genotype, the age, and the environmental conditions. 

To date, 

***> eleven of the atypical scrapie intracerebrally inoculated sheep have succumbed to atypical scrapie disease; 

***> six pigs to sheep BSE; 

***> one cow to classical scrapie; 

***> nine goats to goat BSE and 

***> five goats to classical BSE. 

***> PrPSC has been demonstrated in all cases by immunohistochemistry and western blot. 


=====> PRION CONFERENCE 2018




P.108: Successful oral challenge of adult cattle with classical BSE

Sandor Dudas1,*, Kristina Santiago-Mateo1, Tammy Pickles1, Catherine Graham2, and Stefanie Czub1 1Canadian Food Inspection Agency; NCAD Lethbridge; Lethbridge, Alberta, Canada; 2Nova Scotia Department of Agriculture; Pathology Laboratory; Truro, Nova Scotia, Canada

Classical Bovine spongiform encephalopathy (C-type BSE) is a feed- and food-borne fatal neurological disease which can be orally transmitted to cattle and humans. Due to the presence of contaminated milk replacer, it is generally assumed that cattle become infected early in life as calves and then succumb to disease as adults. Here we challenged three 14 months old cattle per-orally with 100 grams of C-type BSE brain to investigate age-related susceptibility or resistance. During incubation, the animals were sampled monthly for blood and feces and subjected to standardized testing to identify changes related to neurological disease. At 53 months post exposure, progressive signs of central nervous system disease were observed in these 3 animals, and they were euthanized. Two of the C-BSE animals tested strongly positive using standard BSE rapid tests, 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. 

***Our study demonstrates susceptibility of adult cattle to oral transmission of classical BSE. 

We are further examining explanations for the unusual disease presentation in the third challenged animal.



even the atypical h-type BSE was found to be transmissible by oral route, and those findings can be found at the Prion 2018 Conference abstract. 


PRION 2018 CONFERENCE

P98 The agent of H-type bovine spongiform encephalopathy associated with E211K prion protein polymorphism transmits after oronasal challenge 

Greenlee JJ (1), Moore SJ (1), and West Greenlee MH (2) 

(1) United States Department of Agriculture, Agricultural Research Service, National Animal Disease Center, Virus and Prion Research Unit, Ames, IA, United States (2) Department of Biomedical Sciences, Iowa State University College of Veterinary Medicine, Ames, IA, United States. 

In 2006, a case of H-type bovine spongiform encephalopathy (BSE) was reported in a cow with a previously unreported prion protein polymorphism (E211K). 

The E211K polymorphism is heritable and homologous to the E200K mutation in humans that is the most frequent PRNP mutation associated with familial Creutzfeldt-Jakob disease. 

Although the prevalence of the E211K polymorphism is low, cattle carrying the K211 allele develop H-type BSE with a rapid onset after experimental inoculation by the intracranial route. 

The purpose of this study was to investigate whether the agents of H-type BSE or H-type BSE associated with the E211K polymorphism transmit to wild type cattle or cattle with the K211 allele after oronasal exposure. 

Wild type (EE211) or heterozygous (EK211) cattle were oronasally inoculated with either H-type BSE from the 2004 US Htype BSE case (n=3) or from the 2006 US H-type case associated with the E211K polymorphism (n=4) using 10% w/v brain homogenates. 

Cattle were observed daily throughout the course of the experiment for the development of clinical signs. 

At approximately 50 months post-inoculation, one steer (EK211 inoculated with E211K associated H-BSE) developed clinical signs including inattentiveness, loss of body condition, weakness, ataxia, and muscle fasciculations and was euthanized. 

Enzyme immunoassay confirmed that abundant misfolded protein was present in the brainstem, and immunohistochemistry demonstrated PrPSc throughout the brain. 

Western blot analysis of brain tissue from the clinically affected steer was consistent with the E211K H-type BSE inoculum. 

With the experiment currently at 55 months post-inoculation, no other cattle in this study have developed clinical signs suggestive of prion disease. 

This study demonstrates that the H-type BSE agent is transmissible by the oronasal route. 

These results reinforce the need for ongoing surveillance for classical and atypical BSE to minimize the risk of potentially infectious tissues entering the animal or human food chains. 

=====

O10 Zoonotic potential of atypical BSE prions: a systematic evaluation 

Marín-Moreno A (1), Espinosa JC (1), Douet JY (2), Aguilar-Calvo P (1), Píquer J (1), Lorenzo P (1), Lacroux C (2), Huor A (2), Lugan S (2), Tillier C (2), Andreoletti O (2) and Juan María Torres (1) 

(1) Centro de Investigación en Sanidad Animal, CISA-INIA, Carretera Algete-El Casar s/n, Valdeolmos, 28130 Madrid, Spain.(2) UMR INRA ENVT 1225, Interactions Hôtes Agents Pathogènes, Ecole Nationale Vétérinaire de Toulouse, France. 

Bovine Spongiform Encephalopathy (BSE) is the only zoonotic prion recognized to date. The transmission of BSE to humans caused the emergence of variant Creutzfeldt-Jakob disease (vCJD). In 2004 two new atypical prion agents were identified in cattle: H- and L- BSE prion strains. 

The zoonotic potential of atypical BSE prions was assessed by inoculating three different isolates of cattle H- and L-BSE in transgenic mouse lines that overexpress the human PrP covering the three different genotypes of the aminoacid 129 (TgMet129, TgMet/Val129 and TgVal129). This polymorphism is known to be a key element involved in human resistance/susceptibility to BSE. In addition, TgMet129 and TgVal129 were challenged with one H- and L-BSE isolates adapted to sheep PrP expressing hosts to assess if intermediate passage in sheep could modify the capacity of these prions to cross the human species barrier. 

Our results confirm that L-BSE transmits to TgMet129 even better than epidemic BSE. However, atypical L-BSE agent was unable to infect TgVal129 or TgMet/Val129 mice, even after passage in TgMet129. No transmission was observed with H-BSE in any mice model inoculated, irrespectively of the 129 polymorphism. After passage in sheep PrP expressing host, the properties of both H and LBSE including their capacity to cross the human species barrier were dramatically affected, emerging prion strains features that resemble those of sporadic Creutzfeldt-Jakob disease (sCJD). 

To date, this is the more extensive and complete analysis of the zoonotic potential of atypical BSE prions. These results advise not to ignore the zoonotic potential of these agents.

=====

P77 In vitro approach to estimate the human transmission risk of prions 

Iwamaru Y (1) Imamura M (2) Matsuura Y (1) Kohtaro Miyazawa (1) Takashi Yokoyama (3) 

(1 ) National Institute of Animal Health, Prion Disease Unit, Ibaraki, Japan (2) University of Miyazaki, Division of Microbiology, Miyazaki, Japan (3) National Institute of Animal Health, Department of Planning and General Administration, Ibaraki, Japan. 

Prion diseases are fatal neurodegenerative disorders in humans and animals. The key event in the pathogenesis of these disease is the conversion of host-encoded normal cellular prion protein (PrPC) into its pathogenic isoform (PrPSc) and its accumulation in the central nervous system. One of the characteristics of prion is the species barrier that limits the transmission between different species. Currently, bioassays using transgenic mice (Tg) overexpressing PrP of different species have become valuable tools for assessing cross species transmissibility of prions. 

The recent reports describing the emergence of novel bovine spongiform encephalopathy (BSE) from H-BSE and the transmission of chronic wasting disease to swine have generated concerns of human infections of newly identified prions. Although Tg expressing human PrP have been used to model human susceptibility to animal prions, these experiments are costly and time-consuming. In addition, the results of bioassays are influenced by the lines of transgenic mice used and the lifespan of the challenged animals. These factors are needed to be taken into account when assessing the human risk of prions. 

In attempt to develop the more time- and cost-saving method for assessment of the human transmission risk of prions, we performed experiments using protein misfolding cyclic amplification (PMCA) technique to investigate whether PMCA can be compatible with bioassay. Using brain homogenates of Tg expressing bovine PrP as the PrP substrate, we optimized the versatile PMCA condition that could amplify PrPSc from cattle affected with C-, H- or L-BSE. We measured the 50% PMCA seeding activity dose and the 50% lethal dose in 1 g equivalent of C-, H- or L-BSE cattle brain tissue by using PMCA or bioassay, respectively, and assessed the correlations between these doses. 

===== 

 P98 The agent of H-type bovine spongiform encephalopathy associated with E211K prion protein polymorphism transmits after oronasal challenge 

Greenlee JJ (1), Moore SJ (1), and West Greenlee MH (2) (1) United States Department of Agriculture, Agricultural Research Service, National Animal Disease Center, Virus and Prion Research Unit, Ames, IA, United States (2) Department of Biomedical Sciences, Iowa State University College of Veterinary Medicine, Ames, IA, United States. 

reading up on this study from Prion 2018 Conference, very important findings ;

***> This study demonstrates that the H-type BSE agent is transmissible by the oronasal route. 

***> These results reinforce the need for ongoing surveillance for classical and atypical BSE to minimize the risk of potentially infectious tissues entering the animal or human food chains.




WEDNESDAY, AUGUST 15, 2018 

The agent of H-type bovine spongiform encephalopathy associated with E211K prion protein polymorphism transmits after oronasal challenge



Detection of PrPBSE and prion infectivity in the ileal Peyer’s patch of young calves as early as 2 months after oral challenge with classical bovine spongiform encephalopathy 

Ivett Ackermann1 , Anne Balkema‑Buschmann1 , Reiner Ulrich2 , Kerstin Tauscher2 , James C. Shawulu1 , Markus Keller1 , Olanrewaju I. Fatola1 , Paul Brown3 and Martin H. Groschup1* 

Abstract 

In classical bovine spongiform encephalopathy (C-BSE), an orally acquired prion disease of cattle, the ileal Peyer’s patch (IPP) represents the main entry port for the BSE agent. In earlier C-BSE pathogenesis studies, cattle at 4–6 months of age were orally challenged, while there are strong indications that the risk of infection is highest in young animals. In the present study, unweaned calves aged 4–6 weeks were orally challenged to determine the earli‑ est time point at which newly formed PrPBSE and BSE infectivity are detectable in the IPP. For this purpose, calves were culled 1 week as well as 2, 4, 6 and 8 months post-infection (mpi) and IPPs were examined for BSE infectivity using a bovine PrP transgenic mouse bioassay, and for PrPBSE by immunohistochemistry (IHC) and protein misfolding cyclic amplifcation (PMCA) assays. For the frst time, BSE prions were detected in the IPP as early as 2 mpi by transgenic mouse bioassay and PMCA and 4 mpi by IHC in the follicular dendritic cells (FDCs) of the IPP follicles. These data indi‑ cate that BSE prions propagate in the IPP of unweaned calves within 2 months of oral uptake of the agent.

In summary, our study demonstrates for the frst time PrPBSE (by PMCA) and prion infectivity (by mouse bioassay) in the ileal Peyer’s patch (IPP) of young calves as early as 2 months after infection. From 4 mpi nearly all calves showed PrPBSE positive IPP follicles (by IHC), even with PrPBSE accumulation detectable in FDCs in some animals. Finally, our results confrm the IPP as the early port of entry for the BSE agent and a site of initial propagation of PrPBSE and infectivity during the early pathogenesis of the disease. Terefore, our study supports the recommendation to remove the last four metres of the small intestine (distal ileum) at slaughter, as designated by current legal requirements for countries with a controlled BSE risk status, as an essential measure for consumer and public health protection.


. A study comparing preclinical cattle infected naturally with BSE to clinically affected cattle either naturally or experimentally infected with BSE by the oral route found the most abundant PrPSc in the brainstem area (39), which is consistent with ascension to the brain from the gut by sympathetic and parasympathetic projections (40). In our experiment, abundant prions were observed in the brainstem of cattle with clinical signs of BSE, which is similar to the amount in their thalamus or midbrain regions. Interestingly, prions in the brainstem of cattle with clinical evidence of BSE seeded the RT-QuIC reactions faster than any other brain region despite the brainstem area having lower EIA OD values (Table 2) in comparison to other brain regions. This suggests that higher concentrations of prions do not necessarily seed the reaction faster. Perhaps prions of the brainstem exist in a preferred conformation for better conversion despite being present in lower concentrations.

snip...




TUESDAY, NOVEMBER 02, 2010 

BSE - ATYPICAL LESION DISTRIBUTION (RBSE 92-21367) statutory (obex only) diagnostic criteria CVL 1992



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 Terry S. Singeltary Sr. on 03 Jul 2015 at 16:53 GMT



Discussion: The C, L and H type BSE cases in Canada exhibit molecular characteristics similar to those described for classical and atypical BSE cases from Europe and Japan.

*** This supports the theory that the importation of BSE contaminated feedstuff is the source of C-type BSE in Canada.

*** It also suggests a similar cause or source for atypical BSE in these countries. ***

see page 176 of 201 pages...tss



*** Singeltary reply ; Molecular, Biochemical and Genetic Characteristics of BSE in Canada Singeltary reply;



MONDAY, JANUARY 09, 2017

Oral Transmission of L-Type Bovine Spongiform Encephalopathy Agent among Cattle CDC Volume 23, Number 2—February 2017

*** Consumption of L-BSE–contaminated feed may pose a risk for oral transmission of the disease agent to cattle.

*** Consumption of L-BSE–contaminated feed may pose a risk for oral transmission of the disease agent to cattle.

***our findings suggest that possible transmission risk of H-type BSE to sheep and human. Bioassay will be required to determine whether the PMCA products are infectious to these animals.

P.86: Estimating the risk of transmission of BSE and scrapie to ruminants and humans by protein misfolding cyclic amplification

Morikazu Imamura, Naoko Tabeta, Yoshifumi Iwamaru, and Yuichi Murayama

National Institute of Animal Health; Tsukuba, Japan

To assess the risk of the transmission of ruminant prions to ruminants and humans at the molecular level, we investigated the ability of abnormal prion protein (PrPSc) of typical and atypical BSEs (L-type and H-type) and typical scrapie to convert normal prion protein (PrPC) from bovine, ovine, and human to proteinase K-resistant PrPSc-like form (PrPres) using serial protein misfolding cyclic amplification (PMCA).

Six rounds of serial PMCA was performed using 10% brain homogenates from transgenic mice expressing bovine, ovine or human PrPC in combination with PrPSc seed from typical and atypical BSE- or typical scrapie-infected brain homogenates from native host species. In the conventional PMCA, the conversion of PrPC to PrPres was observed only when the species of PrPC source and PrPSc seed matched. However, in the PMCA with supplements (digitonin, synthetic polyA and heparin), both bovine and ovine PrPC were converted by PrPSc from all tested prion strains. On the other hand, human PrPC was converted by PrPSc from typical and H-type BSE in this PMCA condition.

Although these results were not compatible with the previous reports describing the lack of transmissibility of H-type BSE to ovine and human transgenic mice, our findings suggest that possible transmission risk of H-type BSE to sheep and human. Bioassay will be required to determine whether the PMCA products are infectious to these animals.


P.170: Potential detection of oral transmission of H type atypical BSE in cattle using in vitro conversion

***P.170: Potential detection of oral transmission of H type atypical BSE in cattle using in vitro conversion

Sandor Dudas, John G Gray, Renee Clark, and Stefanie Czub Canadian Food Inspection Agency; Lethbridge, AB Canada

Keywords: Atypical BSE, oral transmission, RT-QuIC

The detection of bovine spongiform encephalopathy (BSE) has had a significant negative impact on the cattle industry worldwide. In response, governments took actions to prevent transmission and additional threats to animal health and food safety. While these measures seem to be effective for controlling classical BSE, the more recently discovered atypical BSE has presented a new challenge. To generate data for risk assessment and control measures, we have challenged cattle orally with atypical BSE to determine transmissibility and mis-folded prion (PrPSc) tissue distribution. Upon presentation of clinical symptoms, animals were euthanized and tested for characteristic histopathological changes as well as PrPSc deposition.

The H-type challenged animal displayed vacuolation exclusively in rostral brain areas but the L-type challenged animal showed no evidence thereof. To our surprise, neither of the animals euthanized, which were displaying clinical signs indicative of BSE, showed conclusive mis-folded prion accumulation in the brain or gut using standard molecular or immunohistochemical assays. To confirm presence or absence of prion infectivity, we employed an optimized real-time quaking induced conversion (RT-QuIC) assay developed at the Rocky Mountain Laboratory, Hamilton, USA.

Detection of PrPSc was unsuccessful for brain samples tests from the orally inoculated L type animal using the RT-QuIC. It is possible that these negative results were related to the tissue sampling locations or that type specific optimization is needed to detect PrPSc in this animal. We were however able to consistently detect the presence of mis-folded prions in the brain of the H-type inoculated animal. Considering the negative and inconclusive results with other PrPSc detection methods, positive results using the optimized RT-QuIC suggests the method is extremely sensitive for H-type BSE detection. This may be evidence of the first successful oral transmission of H type atypical BSE in cattle and additional investigation of samples from these animals are ongoing.





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.



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.



 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...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




***> However, at 51 months of incubation or greater, 5 animals were positive by one or more diagnostic methods. Furthermore, positive bioassay results were obtained from all inoculated groups (oral and intracranial; market weight and end of study) suggesting that swine are potential hosts for the agent of scrapie. <***



>*** Although the current U.S. feed ban is based on keeping tissues from TSE infected cattle from contaminating animal feed, swine rations in the U.S. could contain animal derived components including materials from scrapie infected sheep and goats. These results indicating the susceptibility of pigs to sheep scrapie, coupled with the limitations of the current feed ban, indicates that a revision of the feed ban may be necessary to protect swine production and potentially human health. <***


Research Project: Pathobiology, Genetics, and Detection of Transmissible Spongiform Encephalopathies
2017 Annual Report

1a. Objectives (from AD-416):
Objective 1: Investigate the mechanisms of protein misfolding in prion disease, including the genetic determinants of misfolding of the prion protein and the environmental influences on protein misfolding as it relates to prion diseases. Subobjective 1.A: Investigate the differences in the unfolded state of wild-type and disease associated prion proteins to better understand the mechanism of misfolding in genetic prion disease. Subobjective 1.B: Investigate the influence of metal ions on the misfolding of the prion protein in vitro to determine if environmental exposure to metal ions may alter disease progression. Objective 2: Investigate the pathobiology of prion strains in natural hosts, including the influence of prion source genotype on interspecies transmission and the pathobiology of atypical transmissible spongiform encephalopathies (TSEs). Subobjective 2.A: Investigate the pathobiology of atypical TSEs. Subobjective 2.B: Investigate the influence of prion source genotype on interspecies transmission. Objective 3: Investigate sampling methodologies for antemortem detection of prion disease, including the utility of blood sampling as a means to assess prion disease status of affected animals and the utility of environmental sampling for monitoring herd prion disease status. Subobjective 3.A: Investigate the utility of blood sampling as a means to assess prion disease status of affected animals. Subobjective 3.B: Investigate the utility of environmental sampling for monitoring herd prion disease status.

1b. Approach (from AD-416):
The studies will focus on three animal transmissible spongiform encephalopathy (TSE) agents found in the United States: bovine spongiform encephalopathy (BSE); scrapie of sheep and goats; and chronic wasting disease (CWD) of deer, elk, and moose. The research will address sites of protein folding and misfolding as it relates to prion disease, accumulation of misfolded protein in the host, routes of infection, and ante mortem diagnostics with an emphasis on controlled conditions and natural routes of infection. Techniques used will include spectroscopic monitoring of protein folding/misfolding, clinical exams, histopathology, immunohistochemistry, and biochemical analysis of proteins. The enhanced knowledge gained from this work will help understand the underlying mechanisms of prion disease and mitigate the potential for unrecognized epidemic expansions of these diseases in populations of animals that could either directly or indirectly affect food animals.

3. Progress Report:
All 8 project plan milestones for FY17 were fully met. Research efforts directed toward meeting objective 1 of our project plan center around the production of recombinant prion protein from either bacteria or mammalian tissue culture systems and collection of thermodynamic data on the folding of the recombinant prion protein produced. Both bacterial and mammalian expression systems have been established. Thermodynamic data addressing the denatured state of wild-type and a disease associated variant of bovine prion protein has been collected and a manuscript is in preparation. In research pertaining to objective 2, all studies have been initiated and animals are under observation for the development of clinical signs. The animal studies for this objective are long term and will continue until onset of clinical signs. In vitro studies planned in parallel to the animals studies have similarly been initiated and are ongoing. Objective 3 of the project plan focuses on the detection of disease associated prion protein in body fluids and feces collected from a time course study of chronic wasting disease inoculated animals. At this time samples are being collected as planned and methods for analysis are under development.

4. Accomplishments
1. Showed that swine are potential hosts for the scrapie agent. A naturally occurring prion disease has not been recognized in swine, but the agent of bovine spongiform encephalopathy does transmit to swine by experimental routes. Swine are thought to have a robust species barrier when exposed to the naturally occurring prion diseases of other species, but the susceptibility of swine to the agent of sheep scrapie has not been thoroughly tested. ARS researchers at Ames, Iowa conducted this experiment to test the susceptibility of swine to U.S. scrapie isolates by intracranial and oral inoculation. Necropsies were done on a subset of animals at approximately 6 months post inoculation (PI): the time the pigs were expected to reach market weight. Remaining pigs were maintained and monitored for clinical signs of transmissible spongiform encephalopathies (TSE) until study termination at 80 months PI or when removed due to intercurrent disease. Brain samples were examined by multiple diagnostic approaches, and for a subset of pigs in each inoculation group, bioassay in mice expressing porcine prion protein. At 6 months PI, no evidence of scrapie infection was noted by any diagnostic method. However, at 51 months of incubation or greater, 5 animals were positive by one or more diagnostic methods. Furthermore, positive bioassay results were obtained from all inoculated groups (oral and intracranial; market weight and end of study) suggesting that swine are potential hosts for the agent of scrapie. Although the current U.S. feed ban is based on keeping tissues from TSE infected cattle from contaminating animal feed, swine rations in the U.S. could contain animal derived components including materials from scrapie infected sheep and goats. These results indicating the susceptibility of pigs to sheep scrapie, coupled with the limitations of the current feed ban, indicates that a revision of the feed ban may be necessary to protect swine production and potentially human health.
2. Determined that pigs naturally exposed to chronic wasting disease (CWD) may act as a reservoir of CWD infectivity. Chronic wasting disease is a naturally occurring, fatal, neurodegenerative disease of cervids. The potential for swine to serve as a host for the agent of CWD disease is unknown. The purpose of this study was to investigate the susceptibility of swine to the CWD agent following experimental oral or intracranial inoculation. Pigs were assigned to 1 of 3 groups: intracranially inoculated; orally inoculated; or non-inoculated. At market weight age, half of the pigs in each group were tested ('market weight' groups). The remaining pigs ('aged' groups) were allowed to incubate for up to 73 months post inoculation (MPI). Tissues collected at necropsy were examined for disease-associated prion protein (PrPSc) by multiple diagnostic methods. Brain samples from selected pigs were bioassayed in mice expressing porcine prion protein. Some pigs from each inoculated group were positive by one or more tests. Bioassay was positive in 4 out of 5 pigs assayed. Although only small amounts of PrPSc were detected using sensitive methods, this study demonstrates that pigs can serve as hosts for CWD. Detection of infectivity in orally inoculated pigs using mouse bioassay raises the possibility that naturally exposed pigs could act as a reservoir of CWD infectivity. Currently, swine rations in the U.S. could contain animal derived components including materials from deer or elk. In addition, feral swine could be exposed to infected carcasses in areas where CWD is present in wildlife populations. The current feed ban in the U.S. is based exclusively on keeping tissues from TSE infected cattle from entering animal feeds. These results indicating the susceptibility of pigs to CWD, coupled with the limitations of the current feed ban, indicates that a revision of the feed ban may be necessary to protect swine production and potentially human health.
3. Developed a method for amplification and discrimination of the 3 forms of BSE in cattle. The prion protein (PrP) is a protein that is the causative agent of transmissible spongiform encephalopathies (TSEs). The disease process involves conversion of the normal cellular PrP to a pathogenic misfolded conformation. This conversion process can be recreated in the lab using a misfolding amplification process known as real-time quaking induced conversion (RT-QuIC). RT-QuIC allows the detection of minute amounts of the abnormal infectious form of the prion protein by inducing misfolding in a supplied substrate. Although RT-QuIC has been successfully used to detect pathogenic PrP with substrates from a variety of host species, prior to this work bovine prion protein had not been proven for its practical uses for RT-QuIC. We demonstrated that prions from transmissible mink encephalopathy (TME) and BSE-infected cattle can be detected with using bovine prion proteins with RT-QuIC, and developed an RT-QuIC based approach to discriminate different forms of BSE. This rapid and robust method, both to detect and discriminate BSE types, is of importance as the economic implications for different types of BSE vary greatly.
Moore, S., Kunkle, R., Greenlee, M., Nicholson, E., Richt, J., Hamir, A., Waters, W., Greenlee, J. 2016. Horizontal transmission of chronic wasting disease in reindeer. Emerging Infectious Diseases. 22(12):2142-2145. doi:10.3201/eid2212.160635.
Moore, S.J., West Greenlee, M.H., Smith, J.D., Vrentas, C.E., Nicholson, E.M., Greenlee, J.J. 2016. A comparison of classical and H-type bovine spongiform encephalopathy associated with E211K prion protein polymorphism in wild type and EK211 cattle following intracranial inoculation. Frontiers in Veterinary Science. 3:78.
Greenlee, J.J., Kunkle, R.A., Smith, J.D., West Greenlee, M.H. 2016. Scrapie in swine: a diagnostic challenge. Food Safety. 4(4):110-114.
Kondru, N., Manne, S., Greenlee, J., West Greenlee, H., Anantharam, V., Halbur, P., Kanthasamy, A., Kanthasamy, A. 2017. Integrated organotypic slice cultures and RT-QuIC (OSCAR) assay: implications for translational discovery in protein misfolding diseases. Scientific Reports. 7:43155. doi:10.1038/srep43155.
Mammadova, N., Ghaisas, S., Zenitsky, G., Sakaguchi, D.S., Kanthasamy, A.G., Greenlee, J.J., West Greenlee, M.H. 2017. Lasting retinal injury in a mouse model of blast-induced trauma. American Journal of Pathology. 187(7):1459-1472. doi:10.1016/j.ajpath.2017.03.005.




***> However, at 51 months of incubation or greater, 5 animals were positive by one or more diagnostic methods. Furthermore, positive bioassay results were obtained from all inoculated groups (oral and intracranial; market weight and end of study) suggesting that swine are potential hosts for the agent of scrapie. <***



>*** Although the current U.S. feed ban is based on keeping tissues from TSE infected cattle from contaminating animal feed, swine rations in the U.S. could contain animal derived components including materials from scrapie infected sheep and goats. These results indicating the susceptibility of pigs to sheep scrapie, coupled with the limitations of the current feed ban, indicates that a revision of the feed ban may be necessary to protect swine production and potentially human health. <***




J Infect Dis. 1994 Apr;169(4):814-20.

Intracerebral transmission of scrapie to cattle.

Cutlip RC, Miller JM, Race RE, Jenny AL, Katz JB, Lehmkuhl HD, DeBey BM, Robinson MM.

USDA, Agriculture Research Service, National Animal Disease Center, Ames, IA 50010.

To determine if sheep scrapie agent(s) in the United States would induce a disease in cattle resembling bovine spongiform encephalopathy, 18 newborn calves were inoculated intracerebrally with a pooled suspension of brain from 9 sheep with scrapie. Half of the calves were euthanatized 1 year after inoculation. All calves kept longer than 1 year became severely lethargic and demonstrated clinical signs of motor neuron dysfunction that were manifest as progressive stiffness, posterior paresis, general weakness, and permanent recumbency. The incubation period was 14-18 months, and the clinical course was 1-5 months. The brain from each calf was examined for lesions and for protease-resistant prion protein. Lesions were subtle, but a disease-specific isoform of the prion protein was present in the brain of all calves. Neither signs nor lesions were characteristic of those for bovine spongiform encephalopathy.

PMID: 8133096 [PubMed - indexed for MEDLINE]


http://www.ncbi.nlm.nih.gov/pubmed/8133096

doi:10.1016/S0021-9975(97)80022-9

Second passage of a US scrapie agent in cattle

References and further reading may be available for this article. To view references and further reading you must purchase this article.

R.C. Cutlip, J.M. Miller and H.D. Lehmkuhl

United States Department of Agriculture, Agricultural Research Service, National Animal Disease Center, Ames, Iowa, USA

Received 10 September 1996; accepted 31 July 1997. Available online 25 May 2006.

Summary

Scrapie and bovine spongiform encephalopathy are similar chronic neurodegenerative diseases of sheep and cattle. An earlier study showed that, on first passage in cattle, a US scrapie agent caused an encephalopathy that was distinct from bovine spongiform encephalopathy (BSE). The present report describes a second passage in cattle, carried out because diseases caused by the spongiform encephalopathy agents often change in character with additional passages in abnormal hosts. For this work, young calves were inoculated intracerebrally with a pooled suspension of brain from cattle that had died of encephalopathy after experimental inoculation with brain from scrapie-affected sheep. The second passage disease was essentially identical with the first passage disease, as judged by clinical signs, histopathological findings and distribution of “prion protein scrapie” (PrPsc). This represents additional evidence to suggest that the US sheep scrapie agent tested is incapable of causing BSE in cattle.

Correspondence to: R. C. Cutlip, USDA, Agricultural Research Service, National Animal Disease Center, P.O. Box 70, 2300 Dayton Road, Ames, Iowa 50010, USA.


http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WHW-4K1V3NT-9&_user=10&_coverDate=10%2F31%2F1997&_rdoc=1&_fmt=high&_orig=browse&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=12e7528da97a90021a0d9090376b0271



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. ........


http://web.archive.org/web/20030517224223/http://www.bseinquiry.gov.uk/files/yb/1994/02/07002001.pdf


WITH the recent findings that Scrapie will transmit to Macaque by or route, that Scrapie and CWD TSE Prion will transit to pigs orally, recent outbreak documented of TSE Prion Disease in Dromedary Camels, Algeria, atypical TSE Prion still being documented, and again just recently in the USA, of another atypical BSE case, and this discovery was only documented by testing 20k head of cattle from some 100M head of cattle in any given year in the USA, the continued denial that atypical BSE and atypical Scrapie are a transmissible disease (science has shown otherwise) this is concerning to me. Science and scientific policy makers have forgotten what Gibbs, Gajdusek, Hadlow, Alper, Zigas, even Gordon with the infamous Scrapie vaccine blunder, a discovery of valuable importance, and so many others i am failing to remember now, what some found long ago, like Dr. Gibbs, he tried to warn us about scrapie zoonosis potential, yet that went ignored for decades and decades. we/scientist/officials/the world, knows the USA FDA PART 589 TSE PRION FEED ban has failed terribly, the BSE testing has failed terribly, and the surveillance there from has failed, SRM removal breaches, all proven by the OIG or the GAO, and others. But yet, we find ourselves now debating the issue of these same risk factors for scrapie, the same risk factors that we all knew were there, with science staring us in the face, we still deny scientific facts all in the name of corporate interest. let's not continue to make these same mistakes. human and animal life is at stake here. we must remove corporate/government/lobbyist interest from the scientific policy making and regulations there from for the TSE Prion, all of them. ...Terry S. Singeltary SR.

ZOONOSIS OF SCRAPIE TSE PRION

 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, Valerie 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 long 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*** 

=============== 

***our findings suggest that possible transmission risk of H-type BSE to sheep and human. Bioassay will be required to determine whether the PMCA products are infectious to these animals. 

============== 
https://prion2015.files.wordpress.com/2015/05/prion2015abstracts.pdf 

***Transmission data also revealed that several scrapie prions propagate in HuPrP-Tg mice with efficiency comparable to that of cattle BSE. While the efficiency of transmission at primary passage was low, subsequent passages resulted in a highly virulent prion disease in both Met129 and Val129 mice. 

***Transmission of the different scrapie isolates in these mice leads to the emergence of prion strain phenotypes that showed similar characteristics to those displayed by MM1 or VV2 sCJD prion. 

***These results demonstrate that scrapie prions have a zoonotic potential and raise new questions about the possible link between animal and human prions. 
http://www.tandfonline.com/doi/abs/10.1080/19336896.2016.1163048?journalCode=kprn20 


PRION 2016 TOKYO

Saturday, April 23, 2016

SCRAPIE WS-01: Prion diseases in animals and zoonotic potential 2016

Prion. 10:S15-S21. 2016 ISSN: 1933-6896 printl 1933-690X online

Taylor & Francis

Prion 2016 Animal Prion Disease Workshop Abstracts

WS-01: Prion diseases in animals and zoonotic potential

Juan Maria Torres a, Olivier Andreoletti b, J uan-Carlos Espinosa a. Vincent Beringue c. Patricia Aguilar a,

Natalia Fernandez-Borges a. and Alba Marin-Moreno a

"Centro de Investigacion en Sanidad Animal ( CISA-INIA ). Valdeolmos, Madrid. Spain; b UMR INRA -ENVT 1225 Interactions Holes Agents Pathogenes. ENVT. Toulouse. France: "UR892. Virologie lmmunologie MolécuIaires, Jouy-en-Josas. France

Dietary exposure to bovine spongiform encephalopathy (BSE) contaminated bovine tissues is considered as the origin of variant Creutzfeldt Jakob (vCJD) disease in human. To date, BSE agent is the only recognized zoonotic prion.. Despite the variety of Transmissible Spongiform Encephalopathy (TSE) agents that have been circulating for centuries in farmed ruminants there is no apparent epidemiological link between exposure to ruminant products and the occurrence of other form of TSE in human like sporadic Creutzfeldt Jakob Disease (sCJD). However, the zoonotic potential of the diversity of circulating TSE agents has never been systematically assessed. The major issue in experimental assessment of TSEs zoonotic potential lies in the modeling of the ‘species barrier‘, the biological phenomenon that limits TSE agents’ propagation from a species to another. In the last decade, mice genetically engineered to express normal forms of the human prion protein has proved essential in studying human prions pathogenesis and modeling the capacity of TSEs to cross the human species barrier.

To assess the zoonotic potential of prions circulating in farmed ruminants, we study their transmission ability in transgenic mice expressing human PrPC (HuPrP-Tg). Two lines of mice expressing different forms of the human PrPC (129Met or 129Val) are used to determine the role of the Met129Val dimorphism in susceptibility/resistance to the different agents.

These transmission experiments confirm the ability of BSE prions to propagate in 129M- HuPrP-Tg mice and demonstrate that Met129 homozygotes may be susceptible to BSE in sheep or goat to a greater degree than the BSE agent in cattle and that these agents can convey molecular properties and neuropathological indistinguishable from vCJD. However homozygous 129V mice are resistant to all tested BSE derived prions independently of the originating species suggesting a higher transmission barrier for 129V-PrP variant.

Transmission data also revealed that several scrapie prions propagate in HuPrP-Tg mice with efficiency comparable to that of cattle BSE. While the efficiency of transmission at primary passage was low, subsequent passages resulted in a highly virulent prion disease in both Met129 and Val129 mice. 

Transmission of the different scrapie isolates in these mice leads to the emergence of prion strain phenotypes that showed similar characteristics to those displayed by MM1 or VV2 sCJD prion. 

These results demonstrate that scrapie prions have a zoonotic potential and raise new questions about the possible link between animal and human prions. 
http://www.tandfonline.com/doi/abs/10.1080/19336896.2016.1163048?journalCode=kprn20


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

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
https://web.archive.org/web/20170126051158/http://collections.europarchive.org/tna/20080102222950/http://www.bseinquiry.gov.uk/files/yb/1990/09/23001001.pdf


Title: Transmission of scrapie prions to primate after an extended silent incubation period) 

*** In complement to the recent demonstration that humanized mice are susceptible to scrapie, we report here the first observation of direct transmission of a natural classical scrapie isolate to a macaque after a 10-year incubation period. Neuropathologic examination revealed all of the features of a prion disease: spongiform change, neuronal loss, and accumulation of PrPres throughout the CNS. 

*** This observation strengthens the questioning of the harmlessness of scrapie to humans, at a time when protective measures for human and animal health are being dismantled and reduced as c-BSE is considered controlled and being eradicated. 

*** Our results underscore the importance of precautionary and protective measures and the necessity for long-term experimental transmission studies to assess the zoonotic potential of other animal prion strains. 
http://www.ars.usda.gov/research/publications/publications.htm?SEQ_NO_115=313160


***> Moreover, sporadic disease has never been observed in breeding colonies or primate research laboratories, most notably among hundreds of animals over several decades of study at the National Institutes of Health25, and in nearly twenty older animals continuously housed in our own facility. <***

Transmission of scrapie prions to primate after an extended silent incubation period 

Emmanuel E. Comoy, Jacqueline Mikol, Sophie Luccantoni-Freire, Evelyne Correia, Nathalie Lescoutra-Etchegaray, Valérie Durand, Capucine Dehen, Olivier Andreoletti, Cristina Casalone, Juergen A. Richt, Justin J. Greenlee, Thierry Baron, Sylvie L. Benestad, Paul Brown & Jean-Philippe Deslys Scientific Reports volume 5, Article number: 11573 (2015) | Download Citation

Abstract 

Classical bovine spongiform encephalopathy (c-BSE) is the only animal prion disease reputed to be zoonotic, causing variant Creutzfeldt-Jakob disease (vCJD) in humans and having guided protective measures for animal and human health against animal prion diseases. Recently, partial transmissions to humanized mice showed that the zoonotic potential of scrapie might be similar to c-BSE. We here report the direct transmission of a natural classical scrapie isolate to cynomolgus macaque, a highly relevant model for human prion diseases, after a 10-year silent incubation period, with features similar to those reported for human cases of sporadic CJD. Scrapie is thus actually transmissible to primates with incubation periods compatible with their life expectancy, although fourfold longer than BSE. Long-term experimental transmission studies are necessary to better assess the zoonotic potential of other prion diseases with high prevalence, notably Chronic Wasting Disease of deer and elk and atypical/Nor98 scrapie.

SNIP...

Discussion We describe the transmission of spongiform encephalopathy in a non-human primate inoculated 10 years earlier with a strain of sheep c-scrapie. Because of this extended incubation period in a facility in which other prion diseases are under study, we are obliged to consider two alternative possibilities that might explain its occurrence. We first considered the possibility of a sporadic origin (like CJD in humans). Such an event is extremely improbable because the inoculated animal was 14 years old when the clinical signs appeared, i.e. about 40% through the expected natural lifetime of this species, compared to a peak age incidence of 60–65 years in human sporadic CJD, or about 80% through their expected lifetimes. Moreover, sporadic disease has never been observed in breeding colonies or primate research laboratories, most notably among hundreds of animals over several decades of study at the National Institutes of Health25, and in nearly twenty older animals continuously housed in our own facility.

The second possibility is a laboratory cross-contamination. Three facts make this possibility equally unlikely. First, handling of specimens in our laboratory is performed with fastidious attention to the avoidance of any such cross-contamination. Second, no laboratory cross-contamination has ever been documented in other primate laboratories, including the NIH, even between infected and uninfected animals housed in the same or adjacent cages with daily intimate contact (P. Brown, personal communication). Third, the cerebral lesion profile is different from all the other prion diseases we have studied in this model19, with a correlation between cerebellar lesions (massive spongiform change of Purkinje cells, intense PrPres staining and reactive gliosis26) and ataxia. The iron deposits present in the globus pallidus are a non specific finding that have been reported previously in neurodegenerative diseases and aging27. Conversely, the thalamic lesion was reminiscent of a metabolic disease due to thiamine deficiency28 but blood thiamine levels were within normal limits (data not shown). The preferential distribution of spongiform change in cortex associated with a limited distribution in the brainstem is reminiscent of the lesion profile in MM2c and VV1 sCJD patients29, but interspecies comparison of lesion profiles should be interpreted with caution. It is of note that the same classical scrapie isolate induced TSE in C57Bl/6 mice with similar incubation periods and lesional profiles as a sample derived from a MM1 sCJD patient30.

We are therefore confident that the illness in this cynomolgus macaque represents a true transmission of a sheep c-scrapie isolate directly to an old-world monkey, which taxonomically resides in the primate subdivision (parvorder of catarrhini) that includes humans. With an homology of its PrP protein with humans of 96.4%31, cynomolgus macaque constitutes a highly relevant model for assessing zoonotic risk of prion diseases. Since our initial aim was to show the absence of transmission of scrapie to macaques in the worst-case scenario, we obtained materials from a flock of naturally-infected sheep, affecting animals with different genotypes32. This c-scrapie isolate exhibited complete transmission in ARQ/ARQ sheep (332 ± 56 days) and Tg338 transgenic mice expressing ovine VRQ/VRQ prion protein (220 ± 5 days) (O. Andreoletti, personal communication). From the standpoint of zoonotic risk, it is important to note that sheep with c-scrapie (including the isolate used in our study) have demonstrable infectivity throughout their lymphoreticular system early in the incubation period of the disease (3 months-old for all the lymphoid organs, and as early as 2 months-old in gut-associated lymph nodes)33. In addition, scrapie infectivity has been identified in blood34, milk35 and skeletal muscle36 from asymptomatic but scrapie infected small ruminants which implies a potential dietary exposure for consumers.

Two earlier studies have reported the occurrence of clinical TSE in cynomolgus macaques after exposures to scrapie isolates. In the first study, the “Compton” scrapie isolate (derived from an English sheep) and serially propagated for 9 passages in goats did not transmit TSE in cynomolgus macaque, rhesus macaque or chimpanzee within 7 years following intracerebral challenge1; conversely, after 8 supplementary passages in conventional mice, this “Compton” isolate induced TSE in a cynomolgus macaque 5 years after intracerebral challenge, but rhesus macaques and chimpanzee remained asymptomatic 8.5 years post-exposure8. However, multiple successive passages that are classically used to select laboratory-adapted prion strains can significantly modify the initial properties of a scrapie isolate, thus questioning the relevance of zoonotic potential for the initial sheep-derived isolate. The same isolate had also induced disease into squirrel monkeys (new-world monkey)9. A second historical observation reported that a cynomolgus macaque developed TSE 6 years post-inoculation with brain homogenate from a scrapie-infected Suffolk ewe (derived from USA), whereas a rhesus macaque and a chimpanzee exposed to the same inoculum remained healthy 9 years post-exposure1. This inoculum also induced TSE in squirrel monkeys after 4 passages in mice. Other scrapie transmission attempts in macaque failed but had more shorter periods of observation in comparison to the current study. Further, it is possible that there are differences in the zoonotic potential of different scrapie strains.

The most striking observation in our study is the extended incubation period of scrapie in the macaque model, which has several implications. Firstly, our observations constitute experimental evidence in favor of the zoonotic potential of c-scrapie, at least for this isolate that has been extensively studied32,33,34,35,36. The cross-species zoonotic ability of this isolate should be confirmed by performing duplicate intracerebral exposures and assessing the transmissibility by the oral route (a successful transmission of prion strains through the intracerebral route may not necessarily indicate the potential for oral transmission37). However, such confirmatory experiments may require more than one decade, which is hardly compatible with current general management and support of scientific projects; thus this study should be rather considered as a case report.

Secondly, transmission of c-BSE to primates occurred within 8 years post exposure for the lowest doses able to transmit the disease (the survival period after inoculation is inversely proportional to the initial amount of infectious inoculum). The occurrence of scrapie 10 years after exposure to a high dose (25 mg) of scrapie-infected sheep brain suggests that the macaque has a higher species barrier for sheep c-scrapie than c-BSE, although it is notable that previous studies based on in vitro conversion of PrP suggested that BSE and scrapie prions would have a similar conversion potential for human PrP38.

Thirdly, prion diseases typically have longer incubation periods after oral exposure than after intracerebral inoculations: since humans can develop Kuru 47 years after oral exposure39, an incubation time of several decades after oral exposure to scrapie would therefore be expected, leading the disease to occur in older adults, i.e. the peak age for cases considered to be sporadic disease, and making a distinction between scrapie-associated and truly sporadic disease extremely difficult to appreciate.

Fourthly, epidemiologic evidence is necessary to confirm the zoonotic potential of an animal disease suggested by experimental studies. A relatively short incubation period and a peculiar epidemiological situation (e.g., all the first vCJD cases occurring in the country with the most important ongoing c-BSE epizootic) led to a high degree of suspicion that c-BSE was the cause of vCJD. Sporadic CJD are considered spontaneous diseases with an almost stable and constant worldwide prevalence (0.5–2 cases per million inhabitants per year), and previous epidemiological studies were unable to draw a link between sCJD and classical scrapie6,7,40,41, even though external causes were hypothesized to explain the occurrence of some sCJD clusters42,43,44. However, extended incubation periods exceeding several decades would impair the predictive values of epidemiological surveillance for prion diseases, already weakened by a limited prevalence of prion diseases and the multiplicity of isolates gathered under the phenotypes of “scrapie” and “sporadic CJD”.

Fifthly, considering this 10 year-long incubation period, together with both laboratory and epidemiological evidence of decade or longer intervals between infection and clinical onset of disease, no premature conclusions should be drawn from negative transmission studies in cynomolgus macaques with less than a decade of observation, as in the aforementioned historical transmission studies of scrapie to primates1,8,9. Our observations and those of others45,46 to date are unable to provide definitive evidence regarding the zoonotic potential of CWD, atypical/Nor98 scrapie or H-type BSE. The extended incubation period of the scrapie-affected macaque in the current study also underscores the limitations of rodent models expressing human PrP for assessing the zoonotic potential of some prion diseases since their lifespan remains limited to approximately two years21,47,48. This point is illustrated by the fact that the recently reported transmission of scrapie to humanized mice was not associated with clinical signs for up to 750 days and occurred in an extreme minority of mice with only a marginal increase in attack rate upon second passage13. The low attack rate in these studies is certainly linked to the limited lifespan of mice compared to the very long periods of observation necessary to demonstrate the development of scrapie. Alternatively, one could estimate that a successful second passage is the result of strain adaptation to the species barrier, thus poorly relevant of the real zoonotic potential of the original scrapie isolate of sheep origin49. The development of scrapie in this primate after an incubation period compatible with its lifespan complements the study conducted in transgenic (humanized) mice; taken together these studies suggest that some isolates of sheep scrapie can promote misfolding of the human prion protein and that scrapie can develop within the lifespan of some primate species.

In addition to previous studies on scrapie transmission to primate1,8,9 and the recently published study on transgenic humanized mice13, our results constitute new evidence for recommending that the potential risk of scrapie for human health should not be dismissed. Indeed, human PrP transgenic mice and primates are the most relevant models for investigating the human transmission barrier. To what extent such models are informative for measuring the zoonotic potential of an animal TSE under field exposure conditions is unknown. During the past decades, many protective measures have been successfully implemented to protect cattle from the spread of c-BSE, and some of these measures have been extended to sheep and goats to protect from scrapie according to the principle of precaution. Since cases of c-BSE have greatly reduced in number, those protective measures are currently being challenged and relaxed in the absence of other known zoonotic animal prion disease. We recommend that risk managers should be aware of the long term potential risk to human health of at least certain scrapie isolates, notably for lymphotropic strains like the classical scrapie strain used in the current study. Relatively high amounts of infectivity in peripheral lymphoid organs in animals infected with these strains could lead to contamination of food products produced for human consumption. Efforts should also be maintained to further assess the zoonotic potential of other animal prion strains in long-term studies, notably lymphotropic strains with high prevalence like CWD, which is spreading across North America, and atypical/Nor98 scrapie (Nor98)50 that was first detected in the past two decades and now represents approximately half of all reported cases of prion diseases in small ruminants worldwide, including territories previously considered as scrapie free.. Even if the prevailing view is that sporadic CJD is due to the spontaneous formation of CJD prions, it remains possible that its apparent sporadic nature may, at least in part, result from our limited capacity to identify an environmental origin.


Singeltary on Scrapie and human transmission way back, see;


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

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



BSE INQUIRY
 
1979
 
SILENCE ON CJD AND SCRAPIE
 
1980
 
SILENCE ON CJD AND SCRAPIE
 
*** 1981 NOVEMBER
 

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).
 
 
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).
 
 
why do we not want to do TSE transmission studies on chimpanzees $
 
IN CONFIDENCE
 
TRANSMISSION TO CHIMPANZEES
 
snip...
 
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.
 
snip...
 
R. BRADLEY
 
 
full text ;
 
RB3.20
 
IN CONFIDENCE
 
TRANSMISSION TO CHIMPANZEE
 
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, i/p 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.
 
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. CVO (+ Mr. Wells’ comments)
 
Dr. T W A Little
 
Dr. B J Shreeve
 
R Bradley September 1990
 
90/9.23/1/1
 
 
Wednesday, February 16, 2011
 
IN CONFIDENCE
 
SCRAPIE TRANSMISSION TO CHIMPANZEES
 
IN CONFIDENCE
 

Spontaneous TSE Prion disease ???
 
Transmission of scrapie prions to primate after an extended silent incubation period
 
***Moreover, sporadic disease has never been observed in breeding colonies or primate research laboratories, most notably among hundreds of animals over several decades of study at the National Institutes of Health25, and in nearly twenty older animals continuously housed in our own facility.***
 

SUNDAY, OCTOBER 21, 2018 
WEDNESDAY, OCTOBER 24, 2018 

Scotland BSE case not caused by contaminated animal feed? > BSE not caused by contaminated animal feed

LOL! that is the dumbest statement i have heard lately.



Terry S. Singeltary Sr.

posted by Terry S. Singeltary Sr. at 9:22 PM

0 Comments:

Post a Comment

Subscribe to Post Comments [Atom]

<< Home