Annual Report
Creutzfeldt-Jakob disease surveillance in Australia: update to December 2016
Genevieve M Klug, Shannon Sarros, Christiane Stehmann, Marion Simpson, Catriona McLean, Colin L Masters and Steven J Collins
Abstract
Nation-wide surveillance of human transmissible spongiform encephalopathies (TSE, also known as prion diseases), the most common being Creutzfeldt-Jakob disease, is performed by the Australian National Creutzfeldt-Jakob disease Registry, based at the University of Melbourne. Prospective surveillance has been undertaken since 1993 and over this dynamic period in transmissible spongiform encephalopathy research and understanding, the unit has evolved and adapted to changes in surveillance practices and requirements concomitant with the delineation of new disease subtypes, improvements in diagnostic capabilities and the overall heightened awareness of prion diseases in the health care setting. In 2016, routine national surveillance continued and this brief report provides an update of the cumulative surveillance data collected by the Australian National Creutzfeldt-Jakob disease Registry prospectively from 1993 to December 2016, and retrospectively to 1970.
Keywords: Creutzfeldt-Jakob disease, prion disease, transmissible spongiform encephalopathy, disease surveillance
Results
Seventy-one persons with suspected human prion disease were added to the CJD surveillance register in 2016. Cases were initially notified via request for CSF 14-3-3 protein testing (55 cases), personal communication from clinicians (10 cases), the CJD Support Group Network (3 cases), direct health department notification (1 case), family (1 case) and the Victorian Brain Bank Network (1 case). The proportions of the initial notification sources of the 71 cases are consistent with those in previous years and the overall trends for all register cases (Table 1).
Of the 71 cases that were added to register in 2016, 4 cases were known to the ANCJDR prior to 2016 via the CSF 14-3-3 protein test (3 cases) and the CJD Support Group Network (1 case). At the time of referral, these cases were not added to the register due to a low level of suspicion for prion disease after assessment. Further information ascertained in 2016, increased the likelihood of prion disease resulting in formal notification and addition of the cases to the register. The number of case additions to the register in 2016 is higher than the previous year (66 cases) and the average annual number for the years 2004 to 2015 (66 cases).
By state and territory, only modest fluctuations in the number of suspected case notifications compared to the previous year were observed in 2016 (Figure 1). Between 2012 and 2014, the number of suspected case notifications from Western Australia has been lower than the 1993-2015 long-term average (8 cases per year). In 2016, notifications increased and are more closely aligned with the long-term average.
As of 31 December, 2016, the majority of the 71 suspected cases added to the register in 2016 were classified as incomplete (45 cases). Six cases were excluded by either detailed clinical followup (1 case) or neuropathological examination (5 cases); 16 cases were classified as definite and 3 as probable prion disease. The remaining suspect case was initially treated in Australia; however, the patient subsequently returned overseas and was therefore unable to be investigated further. This person was thereby excluded from the overall analysis of Australian prion disease cases.
Excluding the prion disease-related postmortem rate in 2016, wherein figures are still provisional, the average proportion of suspected prion disease cases on the register and who died between 1993 and 2015 and underwent postmortem examination is 60%. Over this period, this proportion has steadily increased from 38% in 1993 to a peak of 80% in 2008. Since 2008, the proportion has stabilized at around 60-65%.
Based on the Australian population, the average crude rate of prion disease-related post-mortems between 1993 and 2016 is 1.4 post-mortems per million per year (range, 0.6-2.0), which is considerable given prion disease is particularly rare. By state and territory and for the same period, the lowest rates of suspected prion disease post-mortems performed annually were in the Australian Capital Territory, Tasmania and Northern Territory (1.0, 0.9 and 0.8 per million per year, respectively) while the highest rates are in Victoria and New South Wales (1.6 per mil- lion per year). Despite the smaller populations in Australian Capital Territory, Tasmania and Northern Territory, the post-mortem rates are not substantially lower than the rates of more populous states and provide a level of confidence that suspected case deaths in these states and territories have a similar likelihood of undergoing post-mortem examination.
In New South Wales and Victoria, there has been an overall temporal increase in postmortem rates between 1993 and 2016 (Figure 2a). Previously, the rate of prion-disease-related post-mortems in New South Wales was reported to have declined sharply in 2014 and this was related to the deferral of analyses by neuropathological laboratory services during this time. As anticipated, upon completion of these analyses in 2015, post-mortem rates for 2014 returned to an expected level in New South Wales.
In Queensland, South Australia and Western Australia, variability in post-mortem rates has been observed especially in recent years. In Queensland, the post-mortem rates in 2013 and 2014 were substantially diminished (0.2 and 0.0 post-mortems per million per year respectively) compared to long-term average for Queensland of 1.2 post-mortems per million per year between 1993 and 2012 and this is directly related to the interruption to routine autopsy services in this state during 2013-2014. In 2015, 5 post-mortems were completed and the post-mortem rate returned to expected levels (1.0 post-mortem per million per year) (Figure 2a) and this trend has continued in 2016. In South Australia and Western Australia, a sustained decrease in the post-mortem examination rate has been observed since 2010-2011. In South Australia, there were a number of suspected prion disease deaths in 2010, 2014, 2015 and 2016 where neuropathological examination remains pending. Once finalised, the post-mortem rates for these years is predicted to return to an expected level but will not change the lower rates in 2012 and 2013. In Western Australia, outstanding post-mortems have been completed, but rates continue to be lower than rates observed prior to 2012 (Figure 2a).
As of 31 December 2016, there were 1,142 cases on the register with 860 of these being classified as probable or definite prion disease cases. An additional definite iatrogenic case who was treated in Australia, and died in the UK is included in Table 2; however this case is not classified as an Australian case due to the location at death and is thereby excluded from the overall statistical analysis of Australian prion disease cases. Since the start of surveillance, 719 suspected prion disease cases have been excluded from the register after detailed follow-up, with 21 of these being excluded in 2016 (7 after neuropathological examination).
In 2016, 31 cases were re-classified from incomplete to definite prion disease and 12 cases to probable prion disease and there were no further cases of possible prion disease classified. The total number of possible cases remains at 15 of which 14 of these cases were sporadic and 1 iatrogenic CJD (Table 2). Of the 266 incomplete cases, 135 are presently alive. In 2016, the total number of incomplete cases under evaluation was only marginally higher than the number in 2015 (259 cases), but still remains significantly higher than the number in 2012 (214 cases) and 2013 (216 cases).
Age-standardised mortality rates show that the rate of human prion disease mortality in Australia during the period of 1970 to 2016 is generally increasing, with the exception of 2016, where case evaluation is pending for the majority of deaths (Figure 3) and incidence is therefore provisional. In 2016, the age-adjusted mortality rate was 0.82 deaths per million per year and this would be expected to increase after further investigation and classification of incomplete cases. The mean annual age-adjusted mortality rate during the period from 1970 – 2015 was 1.0 death per million (range, 0.1-1.8). For the prospective surveillance period of 1993 to 2015, the mean annual rate is 1.3 deaths per million (range, 0.7-1.8). By state and territory, the majority of regions in Australia have a mean ageadjusted mortality rate above 1 case per million per year between 1993 and 2015 (range, 1.0-1.5). The exceptions are Tasmania and the Northern Territory with 0.7 and 0.8 deaths per million per year, respectively. Restriction of the surveillance data to the period between 2003 and 2015 allows comparisons between states and territories during a time-frame of relatively consistent surveillance practices, diagnostic capabilities and utility with the exception of MRI diagnostics (Table 3). During this period, Tasmania and Queensland have lower than expected mean mortality rates, while Western Australia and Victoria have the highest prion disease mortality in Australia.
The proportions of human prion disease aetiologies represented on the register have remained similar to previous years (Figure 4). Previously we have reported that the annual number of genetic prion disease cases had declined in recent years2 although this changed with the classification of 6 confirmed genetic prion disease cases during 2013, 3 in 2015 and 3 in 2016. Overall, the vast majority of human prion disease cases are sporadic (91%) while genetic and iatrogenic cases represent 8 and 1% respectively of all definite and probable cases.
Based on 860 definite and probable human prion disease cases, 54% per cent were female. Similar proportions for gender exist for all human prion disease aetiologies. Median ages at death for the overall case group or by specific aetiology are largely unchanged from the previous reporting period. Sixty-seven years is the median age at death for all cases overall and only a single year difference between males (66 years) and females (67 years). For sporadic cases, 67 years is the median age at death both overall and for males, but a year older in females (68 years). For genetic prion disease, there is a 4 year age difference between males (58 years) and females (62 years) and overall the median age of death from genetic prion disease is 61 years. As there have been no further iatrogenic cases identified since the last reporting period at 31 December 2015, there has been no change to the previously reported median age at death for iatrogenic cases.2
Duration of illness is typically short for human prion disease, especially sporadic CJD, with the median length of illness duration for all cases combined being 4 months. By aetiology, median duration was found to be 3.7 months for sporadic cases (range, 0.9-60 months), 6.25 months for iatrogenic cases (range, 2-25 months) and 6 months for genetic cases (range, 1.25-192 months). Within 6 months of disease onset, 70% of all prion disease cases were deceased. By aetiology, 71% of sporadic, 52% of genetic and 56% of iatrogenic human prion disease were deceased 6 months after the onset of symptoms. Survival is significantly shorter in sporadic CJD than the genetic form (p<0 .0001="" by="" log="" rank="" span="" test="">
Between 1 January and 31 December 2016, no variant CJD or further iatrogenic prion disease cases were identified in Australia. The most recent human-derived pituitary gonadotrophinrelated CJD death occurred in 1991, while the most recent Lyodura-related CJD death occurred in 2000.
Discussion
In 2016, the number of suspected prion disease notifications was slightly greater than the long-term average for the previous 11 years of surveillance (2004 to 2015), however the number does contribute to a period of stability in notifications since 2013. During 2012 and 2013, reduced numbers of notifications were attributed to several possible factors including the temporary interruption of the Queensland suspected prion disease autopsy service, changes to the approach to adding cases to the register for investigation by the ANCJDR and natural fluctuations.
By state and territory, only modest fluctuations in the number of suspected case notifications compared to the previous year were observed in 2016 and are within previously observed ranges. Sizeable relative fluctuations are not surprising with annual CJD notifications given the small absolute case numbers involved; however, it should be noted that since 2009, notifications have been consistently declining in Western Australia. Previous evidence that elevated CSF referrals correspond with elevated suspected prion disease notifications15 led to speculation that lower CSF referrals may be influencing this downward trend in suspected case notifications. CSF referrals from Western Australia have increased annually since the test’s introduction in 1997 to a peak level in 2012. Since 2012, referrals appeared to be trending downward but overall were consistent with pre-2012 levels. The exception was in 2014, where there was a marked decline in CSF referrals. This may explain the lower notifications of suspected cases in 2014, although it does not explain the lower suspect case notifications that have been observed for the remaining years with lower notifications since 2012. As previously discussed, Western Australian health services are relied upon to manage case investigations following notifications and manage autopsy referrals. Changes to the role of the ANCJDR in Western Australia during these years may limit the ANCJDR’s capacity to ascertain the true level of clinical suspicion for CJD, which may have contributed to a reduced number of formal notifications and subsequently, confirmed cases reported by the ANCJDR. In 2016, the decline in notifications appears to have ceased with the number returning to pre-2012 levels and this has coincided with a higher number of CSF referrals. Presently, the number of TSE cases confirmed in 2016 still remains lower than before 2012, however this may change after case investigations of 2016 notifications are completed. The ANCJDR in partnership with the Western Australian Department of Health will continue working towards optimal prion disease ascertainment in Western Australia.
The proportion of prion disease-related postmortems being performed in suspected prion disease cases remains high (60% of all case deaths between 1993 and 2015). This contrasts with the findings of an Australian healthcare setting survey where the national hospital post-mortem rate was 12% in 2002-200316 and more recently, a major Australian tertiary centre audit of hospital autopsy data was published and described an autopsy rate of 6.6% in 2011-2013.17 The high suspected prion disease-related post-mortem proportion underpins the high and consistent number of confirmed Australian human prion disease cases recorded over the more recent time period and provides confident understanding of the cause of death in suspected cases ultimately determined as non-prion disease.
In recent years, interruptions to the routine autopsy services in both New South Wales and Queensland have impacted on the number and timing of post-mortems being completed. From January 2013 to September 2014, a temporary, but practical interruption to brain-only autopsies was in place due to difficulties with a reliable on-call service in Queensland. During this period, no TSE-related autopsies were performed and this was reflected by the significantly lower post-mortem number during this time. Since the current routine service through the Royal Brisbane Hospital became operational towards the end of 2014, expected rates of prion diseaserelated post-mortems have been observed. In New South Wales, the closure of the neuropathology laboratory for refurbishment extended the time required for reporting during 2013 and 2014. As expected, post-mortem rates slowed in 2014 due to reporting delays; these figures have now returned to an expected level now that the laboratory is fully operational.
Rates of post-mortems appear to be slowing in some regions, notably South Australia and Western Australia. In South Australia, this is most likely due to post-mortems not being completed rather than post-mortems not being performed. In Western Australia, a sustained reduction in the number of post-mortems being performed is evident since 2011. Despite notifications and CSF referrals returning to expected levels during 2015/6 in Western Australia, postmortem rates are still low in this state and the reason for this remains unclear.
The number of cases classified as definite and probable prion disease in 2016 was higher than the long-term average number classified annually between 2004 and 2015. In comparison with the previous reporting period, there were 50% more probable cases and 10% more definite cases classified in 2016 than the previous year. This was a result of concerted efforts to evaluate and classify case deaths based upon clinical post-mortems and an increased number of post-mortems being both performed and importantly, completed in 2016. Sixty percent of all post-mortems performed in 2016 were completed by 31st December 2016. This can be attributed in part to the timing of when postmortems were performed during the year but is also a reflection of efficient post-mortem service provision in Australian states and territories.
The higher number of case classifications in 2016 has continued to align prion disease incidence in Australia with previously observed levels and contributes to a period of stable case ascertainment. The heightened case classification number has also contributed to stabilizing the level of incomplete cases currently under investigation. In previous years, there has been an inflation of this case group due to imbalances with the addition of new suspect cases and fully evaluated cases with an outcome. Signs of improvement were evident in 2015, with more case classifications being made in addition to equivalent numbers of suspect cases added and removed from the register after evaluation. This trend has continued in 2016 and will remain an area of focus in 2017.
SATURDAY, FEBRUARY 07, 2015
Annual report Creutzfeldt-Jakob disease surveillance in Australia, 2013
MONDAY, FEBRUARY 24, 2014
UPDATE ON CREUTZFELDT–JAKOB DISEASE Masters et al Australia
Saturday, November 09, 2013
Surveillance for creutzfeldt-Jakob disease in Australia: update to December 2012
SOME OTHER HISTORY HERE PITUITARY HORMONES AND TSE PRION ;
In 1993 the Allar’s inquiry into the use of cadaver-derived pituitary hormones under The Australian Human Pituitary Hormone Program and the association with four medically acquired (iatrogenic) Creutzfeldt-Jakob disease (CJD) deaths recommended the formation of an Australian surveillance unit to monitor further cases of iatrogenic CJD in Australia.1 The Australian National Creutzfeldt-Jakob disease Registry (ANCJDR) was established in October 1993 at the Department of Pathology at the University of Melbourne. The monitoring of further Australian iatrogenic CJD cases related to pituitary hormone treatment for infertility or short stature and contaminated dura mater grafts remains one of the core objectives of the ANCJDR. However, the ANCJDR’s activities have changed to encompass the surveillance of all types of CJD including sporadic, genetic and variant CJD and other transmissible spongiform encephalopathies (TSEs) such as Gerstmann Sträussler-Sheinker Syndrome (GSS) and fatal familial insomnia (FFI).
See more here ;
Background of Australian Human Pituitary Hormone Program From 1967 until 1985 2,100 Australians were treated with human pituitary hormones under the Australian Human Pituitary Hormone Program (AHPHP).
In similar programs in overseas countries the majority of recipients of human pituitary hormones (hPH) were treated with human growth hormone (hGH) for short statue. In Australia the Australian Human Pituitary Hormone Program (AHPHP) treated approximately 1570 woman and about 60 men for infertility using human pituitary gonadotrophin (hPG). Approximately 660 Australian children were treated for short statue with human growth hormone (hGH).
Five Australians may so far have developed and died from health-care associated (iatrogenic) Creutzfeldt-Jakob disease (CJD) after hPH treatment . The program was suspended in 1985 following CJD deaths of recipients of hGH in the United States and England.
All those treated with hPH are at low risk of developing CJD. There is no way of knowing if batches received by recipients were contaminated. To date there is no test to show if recipients are incubating CJD.
The AHPHP was run under the auspices of the Commonwealth Department of Health. The hormones were manufactured by the then government-owned Commonwealth Serum Laboratories in Melbourne.
The AHPHP was conceived and operated by the Human Pituitary Advisory Committee (HPAC) until its activities ceased in 1985 and the committee was disbanded.
From 1992 intense media and political pressure followed news of the first two deaths from iatrogenic CJD as the families demanded an explanation. The then Minister for Health, Senator Graham Richardson, ordered an independent inquiry.
Associate Professor Margaret Allars, an administrative law expert from the University of Sydney conducted the inquiry into the use of Pituitary Derived Hormones in Australia and Creutzfeldt-Jakob Disease, which reported in June 1994.
The inquiry report made a number of recommendations concerning the care of recipients, the establishment of support services and the formation of a ministerial advisory council.
Recipients of hPH now live with a health status of being at “low risk” of CJD. Current infection control guidelines refer to “low risk” patients. Recipients and their families also live with anxiety linked to the threat of contracting a disease which can lie dormant for decades and for which there is no test, treatment or cure.
Tuesday, November 23, 2010
Prosecutors call for prison terms for CJD growth hormone doctors
Tuesday, May 04, 2010
Review of the Human Pituitary Trust Account and CJD Issue 20 January 2010
Creutzfeldt-Jakob Disease, CJD Support Group for short statured children of the 1970's and 1980's. Recommendations for Unapproved/Unregistered recipients
wonder how Michael is doing today ??? hope is all well...
Mr. Michael O'Meara
Senator Bernardi Senator for South Australia Michael O’Meara 120 Port Road P.O. Box 250 Hindmarsh SA 5007 Kinglake 3763 24th February 24, 2009
Dear Senator Bernardi
Re; Senate Committee Inquiry on Men’s Health
It is with regret that the 60 page submission I was preparing for this inquiry was lost in the recent Kinglake Bushfire, along with all other property and possessions of mine, and I now submit an abbreviated submission. Under such personal adversity, I believe this submission falls within the Terms of Reference.
Its is with pleasure that this submission be accepted in accordance with your Notice Of Motion (276) published in November 2008, some 5 months after a Private Member Motion was read in the House of Representatives. The Member for McEwen (Ms Fran Bailey) read a very emotional speech in the House (Committee Room) on 16th June 2008, supported by the Member for Moore, (Dr Mal Washer) and further with bipartisan support by the Rudd Government - expressed by the Members of Page, (Ms Janelle Saffin) and Dobell, (Mr. Craig Thomson)
It is with my pleasure that I submit the following Submission on behalf of myself and all other (then) boys and men treated with Human Pituitary Hormones, unofficially, and not recorded, under the Australian Human Pituitary Hormone Program, and who have suffered, with both short term and long term side effects to the male endocrine system as a result of such Human Experimentation, and with such side effects that are irreversible.
Approved Recipients of Human Growth Hormone or Human Pituitary Gonadotrohpin were subjected to a Senate Inquiry in 1993, known as “The Allars Inquiry”, however – unapproved and/or “Off Program” recipients who were not included in the Allars Inquiry, and whom were not disclosed to the Department of Health and Aging, who are at the same risk of CJD, and were never advised of their risk, particularly unrecorded recipients of hPG at Prince Henry’s Hospital in Melbourne – hundreds of males. The Senate now records (1998) the “Allars Inquiry” was misled.
It is these Males who were “overtreated” with Human Pituitary Gonadotrophin1, who were “overstimulated” through invivo experimentation, with batches varying2 and causing dire consequences to physical, mental and reproductive health - those who were exposed to anabolic steroids (a carcinogenic) as a Growth Promotant with severe side effects. Particular Recommendations were presented and submitted to The Minister for Heath by Professor Margaret Allars in 1994, and further explored by the Senate Affairs Reference Committee in 1998. Of these numerous recommendations, I draw particular reference to Recommendation 5 m stating
That the settlement offer should not preclude a plaintiff making any future claim in relation to: (a) Other physical illnesses contracted by recipients which may be related to long term side effects of HPH treatment3 This submission is dedicated to the Infant boys, Toddlers boys, Prepubescent boys, Teenage boys, Young, Middle Aged and Elderly Men aged 2 to 101 – who were treated under such experimental Programs, exposed to Endocrine Disruptors during the 1970’s, particularly those whom were castrated and sterilized by the Australian Government and/or representatives engaged under the Health Act 1958. Such Section with the Act has since been repealed so that the “experimental nature” of “The Program” cannot happen again - following the “Allars Inquiry”. This does not repeal or repair the ongoing side effects. In particular, I dedicate this submission to the memory of the child who lost his life under these experimental programs at Prince Henry’s Hospital during the 1970’s4.
Please accept my gratitude with appreciation with your efforts in this forthcoming Inquiry.
Yours Faithfully
Michael O’Meara
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see also ;
Michael was recruited into the growth hormone clinic at Prince Henry's Hospital in 1972 when he was just 10 years old. He was subjected to deep sleep therapy in April 1972. At this time he was administered the human growth hormone using products from cadavers. It has since been found that some of this material was contaminated, with a number of young recipients subsequently contracting and dying of the deadly Creutzfeldt-Jakob disease, or CJD.
SNIP...SEE MORE HERE ;
BSE INQUIRY DFAs
Tuesday, March 16, 2010
COMMONWEALTH OF AUSTRALIA Hansard Import restrictions on beef
FRIDAY, 5 FEBRUARY 2010 AUSTRALIA
COMMONWEALTH OF AUSTRALIA
Proof Committee Hansard
RRA&T 2 Senate Friday, 5 February 2010
RURAL AND REGIONAL AFFAIRS AND TRANSPORT
[9.03 am]
BELLINGER, Mr Brad, Chairman, Australian Beef Association CARTER, Mr John Edward, Director, Australian Beef Association CHAIR—Welcome. Would you like to make an opening statement? Mr Bellinger—Thank you. The ABA stands by its submission, which we made on 14 December last year, that the decision made by the government to allow the importation of beef from BSE affected countries is politically based, not science based. During this hearing we will bring forward compelling new evidence to back up this statement. When I returned to my property after the December hearing I received a note from an American citizen. I will read a small excerpt from the mail he sent me in order to reinforce the dangers of allowing the importation of beef from BSE affected countries. I have done a number of press releases on this topic, and this fellow has obviously picked my details up from the internet. His name is Terry Singeltary and he is from Bacliff, Texas. He states, and rightfully so: You should be worried. Please let me explain. I’ve kept up with the mad cow saga for 12 years today, on December 14th 1997, some four months post voluntary and partial mad cow feed ban in the USA, I lost my mother to the Heidenhain variant Creutzfeldt-Jakob disease (CJD). I know this is just another phenotype of the infamous sporadic CJDs. Here in the USA, when USA sheep scrapie was transmitted to USA bovine, the agent was not UK BSE—it was a different strain. So why then would human TSE from USA cattle look like UK CJD from UK BSE? It would not. So this accentuates that the science is inconclusive still on this devastating disease. He goes on to state:
snip...see full text 110 pages ;
new url link;
Australia Atypical scrapie 5 cases diagnosed in 2016
RW Cook,a* J Bingham,bAS Besier,cCL Bayley,dM Hawes,ePL Shearer,fM Yamada,bJ Bergfeld,bDT Williamsband DJ Middletonb
Background
Since its initial detection in Norway in 1998, atypical scrapie (‘atypical/Nor98 scrapie’) has been reported in sheep in the majority of European countries (including in regions free of classical scrapie) and in the Falkland Islands, the USA, Canada,New Zealand and Australia.
Case series
The diagnosis in Australia of atypical scrapie in four Merino and one Merino-cross sheep showing clinical signs of neurological disease was based on the detection of grey matter neuropil vacuolation (spongiform change) in the brain (particularly inthe molecular layer of the cerebellar cortex) and associated abnormal prion protein (PrPSc) deposition in both grey and white matter. Changes were minimal in the caudal brainstem, the predilection site for lesions of classical scrapie.
Conclusion
The distinctive lesion profile of atypical scrapie in these five sheep highlights the diagnostic importance of routine histological evaluation of the cerebellum for evidence of neuropil vacuolation and associated PrPSc deposition in adult sheep with suspected neurological disease.
Keywords atypical scrapie; prion disease; sheep; transmissible spongiform encephalopathy
Abbreviations ANZSDP, Australian and New Zealand StandardDiagnostic Procedure; CNS, central nervous system; DMNV, dorsalmotor nucleus of the vagus nerve; H&E, haematoxylin and eosin;IHC, immunohistochemistry; NTSESP, National TSE SurveillanceProgram; PrPSc, abnormal prion protein isomer; TSE, transmissiblespongiform encephalopathy.
Aust Vet J 2016;94:452–455 doi:http://10.1111/avj.12529
THURSDAY, OCTOBER 7, 2010
Australia first documented case of atypical scrapie confirmed
Review: Update on Classical and Atypical Scrapie in Sheep and Goats
Justin J. Greenlee1
Veterinary Pathology 1-11 ª The Author(s) 2018 Article reuse guidelines: sagepub.com/journals-permissions DOI: 10.1177/0300985818794247 journals.sagepub.com/home/vet
Abstract
Scrapie is a naturally occurring transmissible spongiform encephalopathy (TSE) or prion disease of sheep and goats. Scrapie is a protein misfolding disease where the normal prion protein (PrPC) misfolds into a pathogenic form (PrPSc) that is highly resistant to enzymatic breakdown within the cell and accumulates, eventually leading to neurodegeneration. The amino acid sequence of the prion protein and tissue distribution of PrPSc within affected hosts have a major role in determining susceptibility to and potential environmental contamination with the scrapie agent. Many countries have genotype-based eradication programs that emphasize using rams that express arginine at codon 171 in the prion protein, which is associated with resistance to the classical scrapie agent. In classical scrapie, accumulation of PrPSc within lymphoid and other tissues facilitates environmental contamination and spread of the disease within flocks. A major distinction can be made between classical scrapie strains that are readily spread within populations of susceptible sheep and goats and atypical (Nor-98) scrapie that has unique molecular and phenotype characteristics and is thought to occur spontaneously in older sheep or goats. This review provides an overview of classical and atypical scrapie with consideration of potential transmission of classical scrapie to other mammalian hosts.
Keywords
goats, prion diseases, prion protein, PRNP, PrPSc, review, scrapie, sheep, transmissible spongiform encephalopathies
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Strains
TSE agents can exist in multiple strains that may exhibit different disease phenotypes and pathogenesis.30,143 Strains may be differentiated by clinical signs,126 incubation periods and lesion profiles in mouse models,23,51,52 cellular and neuroanatomical deposition of PrPSc, 24,61 molecular profile on western blot (the apparent molecular mass18 and/or glycoform ratios154 of PrPSc fragments),18 or reactivity to antibodies binding to different regions of PrPSc.
101 Strain properties are maintained through conformational differences in PrPSc as there are no amino acid sequence differences between PrPC and PrPSc. 19,104 The hypothesis that strains arise from differences in protein structure127 is supported by the reaction of different strain isolates to conformational antibodies135 and stability assays.163 It is not known how new strains arise, but it could be due to inherent conformational flexibility of the prion protein, presence of PRNP polymorphisms within a host species, or interspecies transmission events.115 Many scrapie strains are difficult to differentiate by western blot114 but can be differentiated by in-depth analysis of immunoreactivity patterns in multiple brain regions.61,113 A rarely identified sheep scrapie isolate referred to as CH1641 is of note because of an appearance on western blot with some similarities to BSE,80 such as a lower apparent molecular mass of the unglycosylated fragment.154 With the use of a panel of antibodies, CH1641 can be differentiated from BSE by immunohistochemistry85 or western blot.11,12,154 Furthermore, BSE readily transmits to conventional mice,26 whereas CH1641 does not.49 The most important strain designation to recognize in scrapie is between classical scrapie strains (described above) and the more recently described atypical scrapie.
Atypical Scrapie
Atypical (Nor98) scrapie was first detected in Norway in 1998,15,16 but retrospective studies indicate that this phenotype has been present since at least the 1980s.25,166 Atypical scrapie is different from classical scrapie in clinical presentation, molecular characteristics and distribution of PrPSc within infected sheep, genotypes affected, and epidemiology. Atypical scrapie has been identified throughout Europe,9,40,41,47,53 North America,106,111 New Zealand,91 and Australia.34 The worldwide distribution with similar incidence rates where detected supports a separate etiology from classical scrapie47 and that it is spontaneous109 or transmits very poorly under natural conditions.46 Thus, atypical scrapie is recognized as a separate, nonreportable disease by the World Organization for Animal Health (OIE).
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PRNP genotype is a major factor in atypical scrapie cases with polymorphisms at codons 141 (F, phenylalanine) and 154 (H) being highly associated with identified cases. Sheep in the original report carried at least 1 AHQ allele.16 Atypical scrapie has been transmitted experimentally to AHQ sheep by the intracranial145 and oral146 routes. An increased risk of atypical scrapie has also been identified in sheep with the AF141RQ haplotype.137 Atypical scrapie does experimentally transmit to sheep with the AL141RQ haplotype but with very long incubation periods without clinical signs.123 Furthermore, sheep with the ARR haplotype, which confers resistance to classical scrapie and is the cornerstone of genotype-based eradication programs, do not appear to be protected against developing atypical scrapie.41,137
Atypical scrapie has also been reported in goats,103,142 where the molecular profile on western blot is similar to atypical scrapie in sheep, but the distribution of lesions within the brain is more rostral (thalamus and midbrain) than atypical scrapie of sheep.142 Similar to sheep with atypical scrapie, histidine substitution at PRNP codon 154 is a risk factor for atypical scrapie in goats,32 and PrPSc has not been demonstrated in the lymphoid tissues of affected goats.142
Interspecies Transmission
Experimental interspecies transmission of prion agents provides valuable information about potential host ranges. Unsuccessful attempts at interspecies transmission led to the concept of a species barrier, an influence on prion transmission due to mismatches between host and recipient prion amino acid sequence and the resulting structures and folding.17,31,78,79,112,140,162 Species barrier can manifest as complete lack of susceptibility, incomplete attack rates, or prolonged incubation times. Interspecies transmission studies are done to fully assess potential risks to animal health, and potential risks to human health can be studied through the use of transgenic mice expressing human PRNP.
Classical scrapie has been experimentally transmitted to numerous omnivorous species after intracranial inoculation, including European bank voles (Myodes glareolus),42,128 meadow voles (Microtus pennsylvanicus),28 raccoons,72,74 and pigs.66 With the exception of European bank voles, which express PRNP that is permissive to many donor strains,165 these studies suggest a substantial species barrier to infection by natural routes.
One hypothesis for the origin of BSE in the United Kingdom was that it resulted from the passage of a scrapie-like disease into the cattle population168 through the feeding of ruminant derived meat and bone meal (MBM). Experimental studies performed in the United States and United Kingdom demonstrated that classical scrapie does not transmit to cattle by the oral route of inoculation,37,97 and successful transmission after intracranial inoculation results in a disease that is distinguishable from BSE by clinical signs, the molecular profile of PrPSc, and PrPSc deposition patterns in brain sections.21,38,39,94 These studies, however, are far from exhaustive and leave untested the possibilities that prion protein genotype of the donor or transmission of another prion agent such as CH1641 scrapie or atypical scrapie to cattle could have been the origin of BSE.
The agent of BSE has been demonstrated to transmit to other species, including humans.26,141 Small ruminants were likely exposed to the same sources of BSE infectivity as cattle, creating concern that the BSE agent could be misdiagnosed as scrapie90 and represent an additional risk to human health. Experimental studies demonstrate that the agent of BSE transmits to sheep, results in a wide distribution of PrPSc in peripheral tissues and brain,14,50,105 and can transmit horizontally between sheep.13 Most cases of classical sheep scrapie appear to be invariant in western blot profile that is differentiable from BSE,81 but BSE in sheep has some similarities to the CH1641 strain of scrapie (described above). Despite significant surveillance efforts, no natural cases of BSE have been described in sheep, but 2 natural cases of BSE have been identified in goats.44,88,151 One hypothesis as to why these cases have only been identified in goats is that goats are more intensively managed and had higher exposure to contaminated feed concentrates,151 similar to the explanation of why the incidence of BSE is higher in dairy herds relative to beef herds.167
Chronic wasting disease (CWD) is a naturally occurring prion disease of cervids with strong similarities to classical scrapie, including widespread accumulation of PrPSc in the lymphoid and nervous tissues of affected animals.114,144 Chronic wasting disease was first identified in captive cervids, and one hypothesis is that it originated as a cross-species transmission of the classical sheep scrapie agent.170 Experimental studies in white-tailed deer lend support to this hypothesis: inoculation of white-tailed deer results in a 100% attack rate after either intracranial or oronasal inoculation.68 Furthermore, PrPSc is distributed throughout the lymphoid tissues, and samples collected from brainstem have a CWD-like western blot pattern.68 The classical scrapie agent was transmitted to Rocky Mountain elk (Cervus elaphus nelsoni) after experimental intracranial inoculation; however, the results suggest elk are not likely to be susceptible to the classical scrapie agent by more natural routes of exposure. After intracranial inoculation with the classical sheep scrapie agent, only 3 of 6 animals developed neurologic signs, and accumulation of PrPSc was limited to the central nervous system without spreading to lymphoid tissues.73
***> Continued research is needed to clarify the potential risks of the scrapie agent to human health. There is no evidence from epidemiologic studies that the scrapie agent has ever transmitted to humans,22,159 and studies using transgenic mice that express wild-type levels of human PRNP have failed to demonstrate transmission of the classical58 or atypical164,171 scrapie agents. However, the classical scrapie agent has transmitted to cynomolgus macaques (with a slightly different prion protein amino acid sequence than humans)33 and mice overexpressing human PRNP.29 Western blot analysis of brain tissues from these studies demonstrates a molecular profile similar to sporadic CJD, suggesting that ongoing surveillance for potential interspecies transmission events and further studies to clarify potential risks of scrapie transmission to humans are critical.
Acknowledgements
snip...see full text;
***> Thus, atypical scrapie is recognized as a separate, nonreportable disease by the World Organization for Animal Health (OIE).
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.
O9 Permeability of the bovine transmission barrier to Atypical/Nor98 scrapie
Huor A. (1), Vidal E.(2), Espinosa JC (3), Lacroux C.(1), Cassard H.(1), Douet JY.(1), Lugan S.(1), Aron N.(1), Tillier C.(1), Bolea R.(4), Benestad SL.(5), Orge L.(6), Torres JM.(3), and Andréoletti O(1)
1 UMR INRA ENVT 1225, Interactions Hôtes Agents Pathogènes, Ecole Nationale Vétérinaire de Toulouse, 23 Chemin des Capelles 31076 Toulouse, France 2 RTA, Centre de Recerca en Sanitat Animal (CReSA, IRTA-UAB), Campus de la Universitat Autònoma de Barcelona, Bellaterra, Spain 3 CISA- INIA, Valdeolmos, Madrid 28130, Spain 4 University of Zaragoza , Facultad de Veterinaria, C/ Miguel Servet 177 Zaragoza, Spain 5 Norwegian Veterinary Institute, Postboks 750 Sentrum, 0106 Oslo, Norway 6Laboratório Nacional de Investigação Veterinária, Estrada de Benfica 701, 1549-011 Lisboa, Portugal.
Atypical/Nor98 Scrapie has been identified in many countries, including Australia and New Zealand. In the EU small ruminants‘ population, its prevalence was estimated to range between 5 to 8 positive small ruminants per 10,000 tested per year.
The zoonotic potential and the risk that atypical scrapie might represent for other farmed animal species remains unknown.
In this study we investigated the capacity of a panel of Atypical scrapie isolates (n= 8 issued four different countries) to propagate in bovine PrP expressing mice (tgBov).
The inoculation in tgBov of all the selected isolates resulted in Prion propagation. Surprisingly the properties of the TSE agents recovered in tgBov were dramatically different from those present in the original isolates. Their in-depth phenotypic characterization (bioassay in various reporter models, PrPres biochemistry) indicated that atypical scrapie passage through the cattle transmission barrier resulted, in the majority of the cases, in the emergence of classical BSE. Investigations carried-out using highly sensitive in vitro amplification of Prion (PMCA) confirmed the absence of any detectable classical BSE prions in the original isolates.
***> Our findings suggest that cattle exposure to atypical scrapie could be responsible of the occurrence of classical BSE in this species.
***> These results also raise some concerns about the current and future changes in the protection measures that were implemented to mitigate animal and human exposure to TSE agents.
=====
P57 A spontaneous misfolding-associated polymorphism in ovine PRNP(M112I) renders ShTg mice highly susceptible to atypical scrapie
Vidal E (1), Sánchez-Martín M (2), Ordóñez M (1), Eraña H (3), Charco JM (3) Méndez L (2), Pumarola M (4) and Castilla J (3,5).
(1) Centre de Recerca en Sanitat Animal (CReSA)-Institut de Recerca i Tecnologia Agroalimentáries (IRTA), Campus de UAB, Barcelona, Catalonia, Spain (2)Transgenic Facility. Department of Medicine. University of Salamanca,Salamanca, Spain (3) CIC bioGUNE, Parque tecnológico de Bizkaia, Derio, Bizkaia, Spain (4) Departament de Medicina i Cirurgia Animals, Facultat de Veterinária UAB, Barcelona, Catalonia, Spain (5) IKERBASQUE, Basque Foundation for Science, Bilbao, Bizkaia, Spain.
Spontaneous misfolding of human PrP is a long-known event leading among other disorders to sporadic CJD, the most prevalent prion disease in human beings. However, little is known about pathogenesis of sporadic prion diseases in other mammalians such as sheep. The high cost associated to ruminant housing and the scarcity of sporadic TSE cases makes necessary to develop reliable mouse models of these diseases not only to study the pathogenesis but also to test therapeutic approaches.
In vitro amplification experiments using recombinant PrP from different species as substrates show that certain amino acid changes render the PrPC highly susceptible to spontaneous misfolding in unseeded amplification reactions. These changes, when overexpressed in transgenic mice, cause a spontaneous and transmissible prion disease.
Certain, naturally occurring polymorphisms were identified in the equivalent positions in the PRNP of sheep. In particular, polymorphism M112I in the ovine PRNP gene showed enhanced spontaneous misfolding susceptibility in vitro. Thus, as previously done for bank vole and mouse, our objective is to determine if a transgenic mouse model over-expressing this polymorphic PrPC will give rise to a spontaneous and transmissible ovine prion disease. Brains of preclinical and clinical transgenic mice will be used to produce inocula that will be tested for TSE infectivity in known ovine and human transgenic mouse models.
Subsequently, several mouse lines have been generated, on a mouse-PRNP knock out background, with different sheep (ARQ) M112I PrPC expression levels. Two candidate lines have been selected with expression levels of 1,5x and 3x of the PrPC transgene (compared to sheep) in homozigosity.
Since in other transgenic models with this substitution the generated spontaneous prions were atypicallike, we challenged our model with ovine classical and atypical prions to determine its susceptibility.
***>Even though no conclusive indication of spontaneous prion disease has been observed so far in the two lines under study, inoculation with atypical scrapie produced conspicuous neurological clinical signs, brain spongiosis and PrPres deposits as early as 140 days post inoculation (dpi), with a 100% attack rate (mean incubation period of 225 dpi) while animals inoculated with classical scrapie remain free of disease at >340 dpi. Indicating that the M112I substitution is highly permissive to atypical ovine prion misfolding.
This study has been funded by MINECO research project reference AGL2013-46756-P.
=====
P110 Using mass spectrometry to determine the relative susceptibility of PrP polymorphisms to atypical scrapie
Christopher J. Silva (1), Melissa L. Erickson-Beltran (1), Inmaculada Martín-Burriel (2,3), Juan José Badiola (3), Jesús R. Requena (4), Rosa Bolea (3)
1. Produce Safety & Microbiology Research Unit, Western Regional Research Center, United States Department of Agriculture, Agricultural Research Service, Albany, California 94710, United States of America. 2. LAGENBIO, Laboratorio de Genética Bioquímica, Facultad de Veterinaria, IA2 Universidad de Zaragoza, 50013, Zaragoza. 3. Veterinary Faculty, Centro de Investigación en Encefalopatías y Enfermedades Transmisibles Emergentes (CIEETE), Universidad de Zaragoza, 50013, Zaragoza, Spain. 4. CIMUS Biomedical Research Institute & Department of Medical Sciences, University of Santiago de Compostela-IDIS, Santiago de Compostela, Spain. Correspondence to: Christopher J. Silva; USDA, ARS, WRRC 800 Buchanan Street Albany California 94710, USA. Phone 510.559.6135. FAX 510.559.6429. email:christopher.silva@ars.usda.gov.
A novel form of scrapie was described in 1998 and referred to as Nor98 for the country of origin and date of its discovery. Since then it has been found in numerous countries, including New Zealand and Australia, and has been renamed atypical scrapie. Unlike classical scrapie, the epidemiology of this sheep prion (PrPSc) disease is consistent with a sporadic origin. Even though it may arise spontaneously, atypical scrapie can be experimentally transmitted to other sheep. Atypical scrapie is associated with specific PrPC polymorphisms that are different from those associated with classical scrapie. We used a mass spectrometry-based method to determine the relative amount of each PrP polymorphism present in a sample from a heterozygous animal. The total amount and relative amounts of each PrP polymorphism present in PrPSc and PrPC were determined. Each PrP sample was isolated and digested with chymotrypsin to yield a set of characteristic peptides spanning relevant polymorphisms at positions 136, 141, 154, 171 and 172 of sheep PrPC. 15N-labeled internal standards, derived from chymotrypsin digested 15N-labeled rPrP, were used to quantify PrP polymorphisms (ALRRY and ALHQY or ALRQD or AFRQY) present in heterozygous atypical scrapie-infected or uninfected control sheep. Full length and truncated (C1) natively expressed PrPC isolated from atypical scrapie-infected animals showed both PrP polymorphisms are produced in equal amounts. In addition, similar amounts of PrPC are present in either infected or uninfected animals. The amount of PrPSc isolated from infected heterozygotes was variable, but was composed of significant amounts of both PrP polymorphisms, including the ALRRY polymorphism which is highly resistant to classical scrapie. Atypical scrapie infection does not originate from sheep PrPC overexpression. Atypical scrapie prions replicate at comparable rates, in spite of polymorphisms at positions 141, 154, 171, or 172.
=====> PRION CONFERENCE 2018
Research Project: Pathobiology, Genetics, and Detection of Transmissible Spongiform Encephalopathies Location: Virus and Prion Research
Title: Passage of scrapie to deer results in a new phenotype upon return passage to sheep
Author item Greenlee, Justin item Kokemuller, Robyn item Moore, Sarah item West Greenlee, N Submitted to: Prion Publication Type: Abstract Only Publication Acceptance Date: 3/15/2017 Publication Date: N/A Citation: N/A
Interpretive Summary:
Technical Abstract:
Aims: We previously demonstrated that scrapie has a 100% attack rate in white-tailed deer after either intracranial or oral inoculation.
Samples from deer that developed scrapie had two different western blot patterns: samples derived from cerebrum had a banding pattern similar to the scrapie inoculum, but samples from brainstem had a banding pattern similar to CWD.
In contrast, transmission of CWD from white-tailed deer to sheep by the intracranial route has a low attack rate and to-date oronasal exposure has been unsuccessful. The purpose of this study was to determine if sheep are susceptible to oronasal exposure of the scrapie agent derived from white-tailed deer.
Methods: At approximately 5 months of age, Suffolk sheep of various PRNP genotypes were challenged by the oronasal route with 10% brain homogenate derived from either the cerebrum or the brainstem of scrapie-affected deer. Genotypes represented in each inoculation group were VV136RR154QQ171 (n=2), AA136RR154QQ171 (n=2), and AV136RR154QR171 (n=1). After inoculation, sheep were observed daily for clinical signs. Upon development of clinical signs, sheep were killed with an overdose of pentobarbital sodium and necropsied. Tissue samples were tested for the presence of PrPSc by EIA, western blot, and immunohistochemistry (IHC). The No. 13-7 scrapie inoculum used for the deer has a mean incubation period of 20.1 months in sheep with the AA136RR154QQ171 genotype and 26.7 months in sheep with the VV136RR154QQ171 genotype.
Results: Sheep inoculated oronasally with WTD derived scrapie developed disease, but only after inoculation with the inoculum from the cerebrum that had a scrapie-like profile. The first sheep to develop clinical signs at approximately 29 months post inoculation had the VV136RR154QQ171 genotype. Eventually sheep of the AA136RR154QQ171 genotype developed clinical signs, but at a mean incubation of 52 months. At 62 months post-inoculation, none of the sheep inoculated with material from the deer brainstem have developed clinical disease.
Conclusions: The No. 13-7 inoculum used in the original deer experiment readily infects white-tailed deer and sheep of various genotypes by the oronasal route. When inoculum is made from different brain regions of No 13-7 scrapie-infected deer from either cerebrum with a scrapie-like western blot pattern or brainstem with a CWD-like western blot pattern, sheep with the VV136RR154QQ171 genotype are the first to develop clinical signs. This is in contrast to the original No. 13-7 inoculum that has a faster incubation period in sheep with the AA136RR154QQ171 genotype. Similar to experiments conducted with CWD, sheep oronasally inoculated with brainstem material from deer with a CWD-like molecular profile have no evidence of disease after 62 months of incubation.
While scrapie is not known to occur in free-ranging populations of white-tailed deer, experimental cases are difficult to differentiate from CWD.
This work raises the potential concern that scrapie infected deer could serve as a confounding factor to scrapie eradication programs as scrapie from deer seems to be transmissible to sheep by the oronasal route.
Plos Singeltary et al
IBNC Tauopathy or TSE Prion disease, it appears, no one is sure Posted by flounder on 03 Jul 2015 at 16:53 GMT
SHEEP AND BSE
PERSONAL AND CONFIDENTIAL
SHEEP AND BSE
A. The experimental transmission of BSE to sheep.
Studies have shown that the ''negative'' line NPU flock of Cheviots can be experimentally infected with BSE by intracerebral (ic) or oral challenge (the latter being equivalent to 0.5 gram of a pool of four cow brains from animals confirmed to have BSE).
RB264
BSE - TRANSMISSION STUDIES
snip...see;
SUNDAY, JUNE 3, 2018
Clinical, pathological, and molecular features of classical and L-type atypical-BSE in goats
TUESDAY, AUGUST 07, 2018
Passage of scrapie to deer results in a new phenotype upon return passage to sheep
Atypical NOR98 Scrapie to humans as sporadic CJD
Sporadic CJD type 1 and atypical/ Nor98 scrapie are characterized by fine (reticular) deposits, see also ; All of the Heidenhain variants were of the methionine/ methionine type 1 molecular subtype.
ATYPICAL NOR-98, AND IT'S POTENTIAL FOR TRANSMISSION TO HUMANS Prusiner et al ;
A newly identified type of scrapie agent can naturally infect sheep with resistant PrP genotypes
Annick Le Dur*,?, Vincent Béringue*,?, Olivier Andréoletti?, Fabienne Reine*, Thanh Lan Laï*, Thierry Baron§, Bjørn Bratberg¶, Jean-Luc Vilotte?, Pierre Sarradin**, Sylvie L. Benestad¶, and Hubert Laude*,?? +Author Affiliations
*Virologie Immunologie Moléculaires and ?Génétique Biochimique et Cytogénétique, Institut National de la Recherche Agronomique, 78350 Jouy-en-Josas, France; ?Unité Mixte de Recherche, Institut National de la Recherche Agronomique-Ecole Nationale Vétérinaire de Toulouse, Interactions Hôte Agent Pathogène, 31066 Toulouse, France; §Agence Française de Sécurité Sanitaire des Aliments, Unité Agents Transmissibles Non Conventionnels, 69364 Lyon, France; **Pathologie Infectieuse et Immunologie, Institut National de la Recherche Agronomique, 37380 Nouzilly, France; and ¶Department of Pathology, National Veterinary Institute, 0033 Oslo, Norway
***Edited by Stanley B.. Prusiner, University of California, San Francisco, CA (received for review March 21, 2005)
Abstract Scrapie in small ruminants belongs to transmissible spongiform encephalopathies (TSEs), or prion diseases, a family of fatal neurodegenerative disorders that affect humans and animals and can transmit within and between species by ingestion or inoculation. Conversion of the host-encoded prion protein (PrP), normal cellular PrP (PrPc), into a misfolded form, abnormal PrP (PrPSc), plays a key role in TSE transmission and pathogenesis. The intensified surveillance of scrapie in the European Union, together with the improvement of PrPSc detection techniques, has led to the discovery of a growing number of so-called atypical scrapie cases. These include clinical Nor98 cases first identified in Norwegian sheep on the basis of unusual pathological and PrPSc molecular features and "cases" that produced discordant responses in the rapid tests currently applied to the large-scale random screening of slaughtered or fallen animals. Worryingly, a substantial proportion of such cases involved sheep with PrP genotypes known until now to confer natural resistance to conventional scrapie. Here we report that both Nor98 and discordant cases, including three sheep homozygous for the resistant PrPARR allele (A136R154R171), efficiently transmitted the disease to transgenic mice expressing ovine PrP, and that they shared unique biological and biochemical features upon propagation in mice.
*** These observations support the view that a truly infectious TSE agent, unrecognized until recently, infects sheep and goat flocks and may have important implications in terms of scrapie control and public health.
OR
***The pathology features of Nor98 in the cerebellum of the affected sheep showed similarities with those of sporadic Creutzfeldt-Jakob disease in humans.
OR
*** Intriguingly, these conclusions suggest that some pathological features of Nor98 are reminiscent of Gerstmann-Sträussler-Scheinker disease.
PLEASE NOTE http://www.neuroprion.com/
PRION CONFERENCE ABSTRACT LINKS NEUROPRION LINKS ARE NO LONGER AVAILABLE FOR PUBLIC
SO SAD, and i have a feeling, just from the problems from 2018, these conference and information there from in the future, imo, will be harder and harder to get for the layperson...just my opinion, and i do hope i am wrong...tss
see;
P03.141
Aspects of the Cerebellar Neuropathology in Nor98
Gavier-Widén, D1; Benestad, SL2; Ottander, L1; Westergren, E1 1National Veterinary Insitute, Sweden; 2National Veterinary Institute,
Norway Nor98 is a prion disease of old sheep and goats. This atypical form of scrapie was first described in Norway in 1998. Several features of Nor98 were shown to be different from classical scrapie including the distribution of disease associated prion protein (PrPd) accumulation in the brain. The cerebellum is generally the most affected brain area in Nor98. The study here presented aimed at adding information on the neuropathology in the cerebellum of Nor98 naturally affected sheep of various genotypes in Sweden and Norway. A panel of histochemical and immunohistochemical (IHC) stainings such as IHC for PrPd, synaptophysin, glial fibrillary acidic protein, amyloid, and cell markers for phagocytic cells were conducted. The type of histological lesions and tissue reactions were evaluated. The types of PrPd deposition were characterized. The cerebellar cortex was regularly affected, even though there was a variation in the severity of the lesions from case to case. Neuropil vacuolation was more marked in the molecular layer, but affected also the granular cell layer. There was a loss of granule cells. Punctate deposition of PrPd was characteristic. It was morphologically and in distribution identical with that of synaptophysin, suggesting that PrPd accumulates in the synaptic structures. PrPd was also observed in the granule cell layer and in the white matter. The pathology features of Nor98 in the cerebellum of the affected sheep showed similarities with those of sporadic Creutzfeldt-Jakob disease in humans.
***The pathology features of Nor98 in the cerebellum of the affected sheep showed similarities with those of sporadic Creutzfeldt-Jakob disease in humans.
PR-26
NOR98 SHOWS MOLECULAR FEATURES REMINISCENT OF GSS
R. Nonno1, E. Esposito1, G. Vaccari1, E. Bandino2, M. Conte1, B. Chiappini1, S. Marcon1, M. Di Bari1, S.L. Benestad3, U. Agrimi1 1 Istituto Superiore di Sanità, Department of Food Safety and Veterinary Public Health, Rome, Italy (romolo.nonno@iss.it); 2 Istituto Zooprofilattico della Sardegna, Sassari, Italy; 3 National Veterinary Institute, Department of Pathology, Oslo, Norway
Molecular variants of PrPSc are being increasingly investigated in sheep scrapie and are generally referred to as "atypical" scrapie, as opposed to "classical scrapie". Among the atypical group, Nor98 seems to be the best identified. We studied the molecular properties of Italian and Norwegian Nor98 samples by WB analysis of brain homogenates, either untreated, digested with different concentrations of proteinase K, or subjected to enzymatic deglycosylation. The identity of PrP fragments was inferred by means of antibodies spanning the full PrP sequence. We found that undigested brain homogenates contain a Nor98-specific PrP fragment migrating at 11 kDa (PrP11), truncated at both the C-terminus and the N-terminus, and not N-glycosylated. After mild PK digestion, Nor98 displayed full-length PrP (FL-PrP) and N-glycosylated C-terminal fragments (CTF), along with increased levels of PrP11. Proteinase K digestion curves (0,006-6,4 mg/ml) showed that FL-PrP and CTF are mainly digested above 0,01 mg/ml, while PrP11 is not entirely digested even at the highest concentrations, similarly to PrP27-30 associated with classical scrapie. Above 0,2 mg/ml PK, most Nor98 samples showed only PrP11 and a fragment of 17 kDa with the same properties of PrP11, that was tentatively identified as a dimer of PrP11. Detergent solubility studies showed that PrP11 is insoluble in 2% sodium laurylsorcosine and is mainly produced from detergentsoluble, full-length PrPSc. Furthermore, among Italian scrapie isolates, we found that a sample with molecular and pathological properties consistent with Nor98 showed plaque-like deposits of PrPSc in the thalamus when the brain was analysed by PrPSc immunohistochemistry. Taken together, our results show that the distinctive pathological feature of Nor98 is a PrP fragment spanning amino acids ~ 90-155. This fragment is produced by successive N-terminal and C-terminal cleavages from a full-length and largely detergent-soluble PrPSc, is produced in vivo and is extremely resistant to PK digestion.
*** Intriguingly, these conclusions suggest that some pathological features of Nor98 are reminiscent of Gerstmann-Sträussler-Scheinker disease.
119
Sunday, December 12, 2010
EFSA reviews BSE/TSE infectivity in small ruminant tissues News Story 2 December 2010
Sunday, April 18, 2010
SCRAPIE AND ATYPICAL SCRAPIE TRANSMISSION STUDIES A REVIEW 2010
Thursday, December 23, 2010
Molecular Typing of Protease-Resistant Prion Protein in Transmissible Spongiform Encephalopathies of Small Ruminants, France, 2002-2009
Volume 17, Number 1 January 2011
Thursday, November 18, 2010
Increased susceptibility of human-PrP transgenic mice to bovine spongiform encephalopathy following passage in sheep
Monday, April 25, 2011
Experimental Oral Transmission of Atypical Scrapie to Sheep
Volume 17, Number 5-May 2011
Friday, February 11, 2011
Atypical/Nor98 Scrapie Infectivity in Sheep Peripheral Tissues
Thursday, March 29, 2012
atypical Nor-98 Scrapie has spread from coast to coast in the USA 2012
NIAA Annual Conference April 11-14, 2011San Antonio, Texas
Sporadic CJD type 1 and atypical/ Nor98 scrapie are characterized by fine (reticular) deposits, see also ; All of the Heidenhain variants were of the methionine/ methionine type 1 molecular subtype.
*** The discovery of previously unrecognized prion diseases in both humans and animals (i.e., Nor98 in small ruminants) demonstrates that the range of prion diseases might be wider than expected and raises crucial questions about the epidemiology and strain properties of these new forms. We are investigating this latter issue by molecular and biological comparison of VPSPr, GSS and Nor98.
VARIABLY PROTEASE-SENSITVE PRIONOPATHY IS TRANSMISSIBLE ...price of prion poker goes up again $
OR-10: Variably protease-sensitive prionopathy is transmissible in bank voles
Romolo Nonno,1 Michele Di Bari,1 Laura Pirisinu,1 Claudia D’Agostino,1 Stefano Marcon,1 Geraldina Riccardi,1 Gabriele Vaccari,1 Piero Parchi,2 Wenquan Zou,3 Pierluigi Gambetti,3 Umberto Agrimi1 1Istituto Superiore di Sanità; Rome, Italy; 2Dipartimento di Scienze Neurologiche, Università di Bologna; Bologna, Italy; 3Case Western Reserve University; Cleveland, OH USA
Background. Variably protease-sensitive prionopathy (VPSPr) is a recently described “sporadic”neurodegenerative disease involving prion protein aggregation, which has clinical similarities with non-Alzheimer dementias, such as fronto-temporal dementia. Currently, 30 cases of VPSPr have been reported in Europe and USA, of which 19 cases were homozygous for valine at codon 129 of the prion protein (VV), 8 were MV and 3 were MM. A distinctive feature of VPSPr is the electrophoretic pattern of PrPSc after digestion with proteinase K (PK). After PK-treatment, PrP from VPSPr forms a ladder-like electrophoretic pattern similar to that described in GSS cases. The clinical and pathological features of VPSPr raised the question of the correct classification of VPSPr among prion diseases or other forms of neurodegenerative disorders. Here we report preliminary data on the transmissibility and pathological features of VPSPr cases in bank voles.
Materials and Methods. Seven VPSPr cases were inoculated in two genetic lines of bank voles, carrying either methionine or isoleucine at codon 109 of the prion protein (named BvM109 and BvI109, respectively). Among the VPSPr cases selected, 2 were VV at PrP codon 129, 3 were MV and 2 were MM. Clinical diagnosis in voles was confirmed by brain pathological assessment and western blot for PK-resistant PrPSc (PrPres) with mAbs SAF32, SAF84, 12B2 and 9A2.
Results. To date, 2 VPSPr cases (1 MV and 1 MM) gave positive transmission in BvM109. Overall, 3 voles were positive with survival time between 290 and 588 d post inoculation (d.p.i.). All positive voles accumulated PrPres in the form of the typical PrP27–30, which was indistinguishable to that previously observed in BvM109 inoculated with sCJDMM1 cases.
In BvI109, 3 VPSPr cases (2 VV and 1 MM) showed positive transmission until now. Overall, 5 voles were positive with survival time between 281 and 596 d.p.i.. In contrast to what observed in BvM109, all BvI109 showed a GSS-like PrPSc electrophoretic pattern, characterized by low molecular weight PrPres. These PrPres fragments were positive with mAb 9A2 and 12B2, while being negative with SAF32 and SAF84, suggesting that they are cleaved at both the C-terminus and the N-terminus. Second passages are in progress from these first successful transmissions.
Conclusions. Preliminary results from transmission studies in bank voles strongly support the notion that VPSPr is a transmissible prion disease. Interestingly, VPSPr undergoes divergent evolution in the two genetic lines of voles, with sCJD-like features in BvM109 and GSS-like properties in BvI109.
The discovery of previously unrecognized prion diseases in both humans and animals (i.e., Nor98 in small ruminants) demonstrates that the range of prion diseases might be wider than expected and raises crucial questions about the epidemiology and strain properties of these new forms. We are investigating this latter issue by molecular and biological comparison of VPSPr, GSS and Nor98.
Monday, June 27, 2011
Comparison of Sheep Nor98 with Human Variably Protease-Sensitive Prionopathy and Gerstmann-Sträussler-Scheinker Disease
Thursday, October 10, 2013
CJD REPORT 1994 increased risk for consumption of veal and venison and lamb
Monday, November 30, 2009
***> USDA AND OIE COLLABORATE TO EXCLUDE ATYPICAL SCRAPIE NOR-98 ANIMAL HEALTH CODE
Thursday, December 20, 2012
***> OIE GROUP RECOMMENDS THAT SCRAPE PRION DISEASE BE DELISTED, WISHES TO CONTINUE SPREADING IT AROUND THE GLOBE
THURSDAY, APRIL 26, 2018
Scrapie USA update 471 classical and 12 Nor98-like cases confirmed to date
http://scrapie-usa.blogspot.com/2018/04/scrapie-usa-update-471-classical-and-12.html
Scrapie USA update 471 classical and 12 Nor98-like cases confirmed to date
http://scrapie-usa.blogspot.com/2018/04/scrapie-usa-update-471-classical-and-12.html
P.97: Scrapie transmits to white-tailed deer by the oral route and has a molecular profile similar to chronic wasting disease and distinct from the scrapie inoculum
Justin Greenlee1, S JO Moore1, Jodi Smith1, M Heather WestGreenlee2 and Robert Kunkle1
1National Animal Disease Center; Ames, IA USA
2Iowa State University; Ames, IA USA
The purpose of this work was to determine susceptibility of white-tailed deer (WTD) to the agent of sheep scrapie and to compare the resultant PrPSc to that of the original inoculum and chronic wasting disease (CWD). We inoculated WTD by a natural route of exposure (concurrent oral and intranasal (IN); n = 5) with a US scrapie isolate. All scrapie-inoculated deer had evidence of PrPSc accumulation. PrPSc was detected in lymphoid tissues at preclinical time points, and deer necropsied after 28 months post-inoculation had clinical signs, spongiform encephalopathy, and widespread distribution of PrPSc in neural and lymphoid tissues. Western blotting (WB) revealed PrPSc with 2 distinct molecular profiles. WB on cerebral cortex had a profile similar to the original scrapie inoculum, whereas WB of brainstem, cerebellum, or lymph nodes revealed PrPSc with a higher profile resembling CWD. Homogenates with the 2 distinct profiles from WTD with clinical scrapie were further passaged to mice expressing cervid prion protein and intranasally to sheep and WTD. In cervidized mice, the 2 inocula have distinct incubation times. Sheep inoculated intranasally with WTD derived scrapie developed disease, but only after inoculation with the inoculum that had a scrapie-like profile. The WTD study is ongoing, but deer in both inoculation groups are positive for PrPSc by rectal mucosal biopsy.
***In summary, this work demonstrates that WTD are susceptible to the agent of scrapie, 2 distinct molecular profiles of PrPSc are present in the tissues of affected deer, and inoculum of either profile readily passes to deer.
*** After a natural route of exposure, 100% of WTD were susceptible to scrapie.
PO-039: A comparison of scrapie and chronic wasting disease in white-tailed deer Justin Greenlee, Jodi Smith, Eric Nicholson US Dept. Agriculture; Agricultural Research Service, National Animal Disease Center; Ames, IA USA
White-tailed deer are susceptible to the agent of sheep scrapie by intracerebral inoculation
snip...
It is unlikely that CWD will be eradicated from free-ranging cervids, and the disease is likely to continue to spread geographically [10]. However, the potential that white-tailed deer may be susceptible to sheep scrapie by a natural route presents an additional confounding factor to halting the spread of CWD. This leads to the additional speculations that
1) infected deer could serve as a reservoir to infect sheep with scrapie offering challenges to scrapie eradication efforts and
2) CWD spread need not remain geographically confined to current endemic areas, but could occur anywhere that sheep with scrapie and susceptible cervids cohabitate.
This work demonstrates for the first time that white-tailed deer are susceptible to sheep scrapie by intracerebral inoculation with a high attack rate and that the disease that results has similarities to CWD. These experiments will be repeated with a more natural route of inoculation to determine the likelihood of the potential transmission of sheep scrapie to white-tailed deer. If scrapie were to occur in white-tailed deer, results of this study indicate that it would be detected as a TSE, but may be difficult to differentiate from CWD without in-depth biochemical analysis.
2012
PO-039: A comparison of scrapie and chronic wasting disease in white-tailed deer
Justin Greenlee, Jodi Smith, Eric Nicholson US Dept. Agriculture; Agricultural Research Service, National Animal Disease Center; Ames, IA USA
snip...
The results of this study suggest that there are many similarities in the manifestation of CWD and scrapie in WTD after IC inoculation including early and widespread presence of PrPSc in lymphoid tissues, clinical signs of depression and weight loss progressing to wasting, and an incubation time of 21-23 months. Moreover, western blots (WB) done on brain material from the obex region have a molecular profile similar to CWD and distinct from tissues of the cerebrum or the scrapie inoculum. However, results of microscopic and IHC examination indicate that there are differences between the lesions expected in CWD and those that occur in deer with scrapie: amyloid plaques were not noted in any sections of brain examined from these deer and the pattern of immunoreactivity by IHC was diffuse rather than plaque-like.
*** After a natural route of exposure, 100% of WTD were susceptible to scrapie.
Deer developed clinical signs of wasting and mental depression and were necropsied from 28 to 33 months PI. Tissues from these deer were positive for PrPSc by IHC and WB. Similar to IC inoculated deer, samples from these deer exhibited two different molecular profiles: samples from obex resembled CWD whereas those from cerebrum were similar to the original scrapie inoculum. On further examination by WB using a panel of antibodies, the tissues from deer with scrapie exhibit properties differing from tissues either from sheep with scrapie or WTD with CWD. Samples from WTD with CWD or sheep with scrapie are strongly immunoreactive when probed with mAb P4, however, samples from WTD with scrapie are only weakly immunoreactive. In contrast, when probed with mAb’s 6H4 or SAF 84, samples from sheep with scrapie and WTD with CWD are weakly immunoreactive and samples from WTD with scrapie are strongly positive. This work demonstrates that WTD are highly susceptible to sheep scrapie, but on first passage, scrapie in WTD is differentiable from CWD.
2011
*** After a natural route of exposure, 100% of white-tailed deer were susceptible to scrapie.
2018 USDA ARS RESEARCH AND PRION CONFERENCE 2018
CWD CWD CWD PIGS PIGS PIGS SCRAPIE SCRAPIE SCRAPIE
Scrapie, CWD, tse prion, transmit to pigs by oral route
***> 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. <***
***> Results: PrPSc was not detected by EIA and IHC in any RPLNs. All tonsils and MLNs were negative by IHC, though the MLN from one pig in the oral <6 5="" 6="" at="" by="" detected="" eia.="" examined="" group="" in="" intracranial="" least="" lymphoid="" month="" months="" of="" one="" pigs="" positive="" prpsc="" quic="" the="" tissues="" was="">6 months group, 5/6 pigs in the oral <6 4="" and="" group="" months="" oral="">6 months group. Overall, the MLN was positive in 14/19 (74%) of samples examined, the RPLN in 8/18 (44%), and the tonsil in 10/25 (40%).
***> Conclusions: This study demonstrates that PrPSc accumulates in lymphoid tissues from pigs challenged intracranially or orally with the CWD agent, and can be detected as early as 4 months after challenge. CWD-infected pigs rarely develop clinical disease and if they do, they do so after a long incubation period.
This raises the possibility that CWD-infected pigs could shed prions into their environment long before they develop clinical disease.
Furthermore, lymphoid tissues from CWD-infected pigs could present a potential source of CWD infectivity in the animal and human food chains.
MONDAY, NOVEMBER 26, 2018
***>The agent of chronic wasting disease from pigs is infectious in transgenic mice expressing human PRNP
FRIDAY, APRIL 20, 2018
*** Scrapie Transmits To Pigs By Oral Route, what about the terribly flawed USA tse prion feed ban?
Research Project: Pathobiology, Genetics, and Detection of Transmissible Spongiform Encephalopathies
***> Subject: Scrapie Transmits To Pigs By Oral Route, what about the terribly flawed USA tse prion feed ban? <***
MONDAY, OCTOBER 01, 2018
Update on Classical and Atypical Scrapie in Sheep and Goats: Review 2018
MONDAY, OCTOBER 1, 2018
Review: Update on Classical and Atypical Scrapie in Sheep and Goats
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.
==============
***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.
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.
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
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.
***> 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.
***> 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.
***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.
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?
Friday, December 14, 2018
FSIS Recalling 10,828 pounds raw intact bone-in beef quarters cattle Products may contain Specified Risk Materials (SRM) MOST HIGH RISK FOR BSE MAD COW DISEASE
***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;
Tuesday, April 19, 2016
Docket No. FDA-2013-N-0764 for Animal Feed Regulatory Program Standards Singeltary Comment Submission
TUESDAY, APRIL 18, 2017
*** EXTREME USA FDA PART 589 TSE PRION FEED LOOP HOLE STILL EXIST, AND PRICE OF POKER GOES UP ***
***> 2018 URGENT DATA <***
***2018***
Cervid to human prion transmission
Kong, Qingzhong
Case Western Reserve University, Cleveland, OH, United States
Abstract
Prion disease is transmissible and invariably fatal. Chronic wasting disease (CWD) is the prion disease affecting deer, elk and moose, and it is a widespread and expanding epidemic affecting 22 US States and 2 Canadian provinces so far. CWD poses the most serious zoonotic prion transmission risks in North America because of huge venison consumption (>6 million deer/elk hunted and consumed annually in the USA alone), significant prion infectivity in muscles and other tissues/fluids from CWD-affected cervids, and usually high levels of individual exposure to CWD resulting from consumption of the affected animal among often just family and friends. However, we still do not know whether CWD prions can infect humans in the brain or peripheral tissues or whether clinical/asymptomatic CWD zoonosis has already occurred, and we have no essays to reliably detect CWD infection in humans.
We hypothesize that:
(1) The classic CWD prion strain can infect humans at low levels in the brain and peripheral lymphoid tissues;
(2) The cervid-to-human transmission barrier is dependent on the cervid prion strain and influenced by the host (human) prion protein (PrP) primary sequence;
(3) Reliable essays can be established to detect CWD infection in humans; and
(4) CWD transmission to humans has already occurred. We will test these hypotheses in 4 Aims using transgenic (Tg) mouse models and complementary in vitro approaches.
Aim 1 will prove that the classical CWD strain may infect humans in brain or peripheral lymphoid tissues at low levels by conducting systemic bioassays in a set of humanized Tg mouse lines expressing common human PrP variants using a number of CWD isolates at varying doses and routes. Experimental human CWD samples will also be generated for Aim 3.
Aim 2 will test the hypothesis that the cervid-to-human prion transmission barrier is dependent on prion strain and influenced by the host (human) PrP sequence by examining and comparing the transmission efficiency and phenotypes of several atypical/unusual CWD isolates/strains as well as a few prion strains from other species that have adapted to cervid PrP sequence, utilizing the same panel of humanized Tg mouse lines as in Aim 1.
Aim 3 will establish reliable essays for detection and surveillance of CWD infection in humans by examining in details the clinical, pathological, biochemical and in vitro seeding properties of existing and future experimental human CWD samples generated from Aims 1-2 and compare them with those of common sporadic human Creutzfeldt-Jakob disease (sCJD) prions.
Aim 4 will attempt to detect clinical CWD-affected human cases by examining a significant number of brain samples from prion-affected human subjects in the USA and Canada who have consumed venison from CWD-endemic areas utilizing the criteria and essays established in Aim 3. The findings from this proposal will greatly advance our understandings on the potential and characteristics of cervid prion transmission in humans, establish reliable essays for CWD zoonosis and potentially discover the first case(s) of CWD infection in humans.
Public Health Relevance
There are significant and increasing human exposure to cervid prions because chronic wasting disease (CWD, a widespread and highly infectious prion disease among deer and elk in North America) continues spreading and consumption of venison remains popular, but our understanding on cervid-to-human prion transmission is still very limited, raising public health concerns. This proposal aims to define the zoonotic risks of cervid prions and set up and apply essays to detect CWD zoonosis using mouse models and in vitro methods. The findings will greatly expand our knowledge on the potentials and characteristics of cervid prion transmission in humans, establish reliable essays for such infections and may discover the first case(s) of CWD infection in humans.
Funding Agency
Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
ZOONOTIC CHRONIC WASTING DISEASE CWD TSE PRION UPDATE
here is the latest;
PRION 2018 CONFERENCE
Oral transmission of CWD into Cynomolgus macaques: signs of atypical disease, prion conversion and infectivity in macaques and bio-assayed transgenic mice
Hermann M. Schatzl, Samia Hannaoui, Yo-Ching Cheng, Sabine Gilch (Calgary Prion Research Unit, University of Calgary, Calgary, Canada) Michael Beekes (RKI Berlin), Walter Schulz-Schaeffer (University of Homburg/Saar, Germany), Christiane Stahl-Hennig (German Primate Center) & Stefanie Czub (CFIA Lethbridge). To date, BSE is the only example of interspecies transmission of an animal prion disease into humans. The potential zoonotic transmission of CWD is an alarming issue and was addressed by many groups using a variety of in vitro and in vivo experimental systems. Evidence from these studies indicated a substantial, if not absolute, species barrier, aligning with the absence of epidemiological evidence suggesting transmission into humans. Studies in non-human primates were not conclusive so far, with oral transmission into new-world monkeys and no transmission into old-world monkeys. Our consortium has challenged 18 Cynomolgus macaques with characterized CWD material, focusing on oral transmission with muscle tissue. Some macaques have orally received a total of 5 kg of muscle material over a period of 2 years.
After 5-7 years of incubation time some animals showed clinical symptoms indicative of prion disease, and prion neuropathology and PrPSc deposition were detected in spinal cord and brain of some euthanized animals. PrPSc in immunoblot was weakly detected in some spinal cord materials and various tissues tested positive in RT-QuIC, including lymph node and spleen homogenates. To prove prion infectivity in the macaque tissues, we have intracerebrally inoculated 2 lines of transgenic mice, expressing either elk or human PrP. At least 3 TgElk mice, receiving tissues from 2 different macaques, showed clinical signs of a progressive prion disease and brains were positive in immunoblot and RT-QuIC. Tissues (brain, spinal cord and spleen) from these and pre-clinical mice are currently tested using various read-outs and by second passage in mice. Transgenic mice expressing human PrP were so far negative for clear clinical prion disease (some mice >300 days p.i.). In parallel, the same macaque materials are inoculated into bank voles.
Taken together, there is strong evidence of transmissibility of CWD orally into macaques and from macaque tissues into transgenic mouse models, although with an incomplete attack rate.
The clinical and pathological presentation in macaques was mostly atypical, with a strong emphasis on spinal cord pathology.
Our ongoing studies will show whether the transmission of CWD into macaques and passage in transgenic mice represents a form of non-adaptive prion amplification, and whether macaque-adapted prions have the potential to infect mice expressing human PrP.
The notion that CWD can be transmitted orally into both new-world and old-world non-human primates asks for a careful reevaluation of the zoonotic risk of CWD..
***> The notion that CWD can be transmitted orally into both new-world and old-world non-human primates asks for a careful reevaluation of the zoonotic risk of CWD. <***
READING OVER THE PRION 2018 ABSTRACT BOOK, LOOKS LIKE THEY FOUND THAT from this study ;
P190 Human prion disease mortality rates by occurrence of chronic wasting disease in freeranging cervids, United States
Abrams JY (1), Maddox RA (1), Schonberger LB (1), Person MK (1), Appleby BS (2), Belay ED (1) (1) Centers for Disease Control and Prevention (CDC), National Center for Emerging and Zoonotic Infectious Diseases, Atlanta, GA, USA (2) Case Western Reserve University, National Prion Disease Pathology Surveillance Center (NPDPSC), Cleveland, OH, USA..
SEEMS THAT THEY FOUND Highly endemic states had a higher rate of prion disease mortality compared to non-CWD states.
AND ANOTHER STUDY;
P172 Peripheral Neuropathy in Patients with Prion Disease
Wang H(1), Cohen M(1), Appleby BS(1,2) (1) University Hospitals Cleveland Medical Center, Cleveland, Ohio (2) National Prion Disease Pathology Surveillance Center, Cleveland, Ohio..
IN THIS STUDY, THERE WERE autopsy-proven prion cases from the National Prion Disease Pathology Surveillance Center that were diagnosed between September 2016 to March 2017,
AND
included 104 patients. SEEMS THEY FOUND THAT The most common sCJD subtype was MV1-2 (30%), followed by MM1-2 (20%),
AND
THAT The Majority of cases were male (60%), AND half of them had exposure to wild game.
snip...see more on Prion 2017 Macaque study from Prion 2017 Conference and other updated science on cwd tse prion zoonosis below...terry
Molecular Barriers to Zoonotic Transmission of Prions
Marcelo A. Barria, Aru Balachandran, Masanori Morita, Tetsuyuki Kitamoto, Rona Barron, Jean Manson, Richard Knight, James W. Ironside, and Mark W. Headcorresponding author
snip...
The conversion of human PrPC by CWD brain homogenate in PMCA reactions was less efficient when the amino acid at position 129 was valine rather than methionine.
***Furthermore, the form of human PrPres produced in this in vitro assay when seeded with CWD, resembles that found in the most common human prion disease, namely sCJD of the MM1 subtype.
snip...
However, we can say with confidence that under the conditions used here, none of the animal isolates tested were as efficient as C-type BSE in converting human PrPC, which is reassuring.
***Less reassuring is the finding that there is no absolute barrier to the conversion of human PrPC by CWD prions in a protocol using a single round of PMCA and an entirely human substrate prepared from the target organ of prion diseases, the brain.
zoonosis of the transmissible spongiform encephalopathy tse prion disease
Cervid to human prion transmission 5R01NS088604-04 Update December 14, 2018
Rapid recontamination of a farm building occurs after attempted prion removal
Kevin Christopher Gough, BSc (Hons), PhD1, Claire Alison Baker, BSc (Hons)2, Steve Hawkins, MIBiol3, Hugh Simmons, BVSc, MRCVS, MBA, MA3, Timm Konold, DrMedVet, PhD, MRCVS3 and Ben Charles Maddison, BSc (Hons), PhD2
Author affiliations
School of Veterinary Medicine and Science, The University of Nottingham, Loughborough, UK ADAS, School of Veterinary Medicine and Science, The University of Nottingham, Loughborough, UK Animal Sciences Unit, Pathology Department, Animal & Plant Health Agency Weybridge, New Haw, Addlestone, Surrey, UK E-mail for correspondence; ben.maddison@adas.co.uk
Abstract
The transmissible spongiform encephalopathy scrapie of sheep/goats and chronic wasting disease of cervids are associated with environmental reservoirs of infectivity.
Preventing environmental prions acting as a source of infectivity to healthy animals is of major concern to farms that have had outbreaks of scrapie and also to the health management of wild and farmed cervids.
Here, an efficient scrapie decontamination protocol was applied to a farm with high levels of environmental contamination with the scrapie agent.
Post-decontamination, no prion material was detected within samples taken from the farm buildings as determined using a sensitive in vitro replication assay (sPMCA).
A bioassay consisting of 25 newborn lambs of highly susceptible prion protein genotype VRQ/VRQ introduced into this decontaminated barn was carried out in addition to sampling and analysis of dust samples that were collected during the bioassay.
Twenty-four of the animals examined by immunohistochemical analysis of lymphatic tissues were scrapie-positive during the bioassay, samples of dust collected within the barn were positive by month 3.
The data illustrates the difficulty in decontaminating farm buildings from scrapie, and demonstrates the likely contribution of farm dust to the recontamination of these environments to levels that are capable of causing disease.
snip...
PrPC is ubiquitous in its distribution in vivo2 and with both scrapie and CWD the in vivo dissemination of infectivity is also widespread with PrPSc usually accumulating within peripheral lymphatic tissues before the CNS.3 4 With scrapie, PrPSc can be secreted/ excreted via a multiplicity of routes including saliva,5 6 milk,7 faeces,8 skin9 and urine.10 The accumulation of this material within the environment (particularly the built farm environment),11 12 creates levels of infectivity that can be transmitted to naïve animals. These reservoirs of infectivity can remain infectious for prolonged periods of time, in one such recorded incident at least 16 years.13 The advent of high sensitivity prion replication assays such as protein misfolding cyclic amplification (PMCA) with application to sheep/goat scrapie14 15 has allowed the monitoring of prions within environments.11
Attempts to decontaminate pens on a scrapie-affected farm and measuring efficacy using a sheep bioassay were previously reported.12 It was concluded that the failure of effective decontamination within that study was likely to have been due to the incomplete farm decontamination and the presence of dust containing infectious prions that recontaminated the pen surfaces. The serial protein misfolding cyclic amplification (sPMCA) technique was recently used to confirm the presence of prions within extracts prepared from dust samples that had settled on sterile surfaces.16 Given the presence of mobile infectious prions within dust, it was proposed that for effective scrapie decontamination emphasis should be given to the removal of all sources of dust within the decontamination strategy for a farm. More recently, the sPMCA technique has been used by the authors' laboratory to look at effective methods of decontaminating prions bound to concrete surfaces within the laboratory setting.17 This study demonstrated that current methodology based on a one-hour exposure to 20000 ppm free chlorine was likely to be ineffective at removing surface-bound scrapie prion. However, there was an enhanced effectiveness of this chemical decontamination when using multiple applications over four hours. Here, a study is described where a scrapie-affected farm was decontaminated using four applications of 20000 ppm free chlorine to livestock barns and concreted areas. The decontamination also included a high-level clean of the buildings that had housed sheep to remove all traces of dust as far as practicable before the chemical decontamination procedure. Following these treatments the surfaces within the barn were demonstrably free from prion using a sensitive sPMCA assay. The presence of any residual infectivity was then evaluated by sheep bioassay and dust samples collected during the bioassay were assayed for prion seeding activity by sPMCA.
snip...
Discussion
The authors' previous work on this farm indicated that dust harbours low levels of mobile scrapie prions that can accumulate on surfaces16 and this is likely to perpetuate transmission of scrapie within such a farm environment.12 In addition, previous in vitro modelling of scrapie prions bound to a concrete ‘fomite’ demonstrated that prion seeding activity could be inactivated by four applications of 20,000 ppm free chlorine as measured by a sPMCA assay. This previous modelling demonstrated that residual contamination of the swab extract with hypochlorite at levels which would inhibit the sPMCA are unlikely, and the authors consider these results as reduction in seeding titre.17 Here, this same decontamination methodology was tested within a farm-scale study which also included steps to remove dust within the barns. This study demonstrated that this thorough decontamination method applied to a farm with a high incidence of naturally acquired scrapie was sufficient to remove scrapie prions on surfaces to levels that were undetectable by sPMCA, one of the most sensitive biochemical assays for prions. The authors' sPMCA assay has an limit of detection of around 1–10pg scrapie-infected sheep brain per sPMCA reaction. The authors assume that the samples negative by sPMCA had less than this amount (of brain equivalent) within the extracts that were prepared. This treatment together with measures designed to minimise the amount of dust retained within the buildings (vacuuming all surfaces, pressure washing and then hypochlorite treatment) was expected to have removed all infectivity from the buildings and the concrete areas surrounding them, and it was anticipated that the sheep bioassay would confirm absence of infective prion.
However, the introduction into this decontaminated barn of 25 VRQ/VRQ sheep (a genotype highly susceptible to classical scrapie) demonstrated that all animals, with the exception of 1 lamb that died at 122 dpe, had detectable PrPSc in lymphoid tissue, indicating infection with the scrapie agent. This included 14 animals (54 per cent) that were PrPSc-positive on the first RAMALT analysis at 372 dpe or 419 dpe. Although infected sheep were removed based on a positive RAMALT result, it is possible that lateral transmission or subsequent contamination of the environment from infected sheep had contributed to the rapid spread of scrapie in nearly all sheep. It has been shown previously that objects in contact with scrapie-infected sheep, such as water troughs and fence posts, can act as a reservoir for infection.23 As in the authors' previous study,12 the decontamination of this sheep barn was not effective at removing scrapie infectivity, and despite the extra measures brought into this study (more effective chemical treatment and removal of sources of dust) the overall rates of disease transmission mirror previous results on this farm. With such apparently effective decontamination (assuming that at least some sPMCA seeding ability is coincident with infectivity), how was infectivity able to persist within the environment and where does infectivity reside? Dust samples were collected in both the bioassay barn and also a barn subject to the same decontamination regime within the same farm (but remaining unoccupied). Within both of these barns dust had accumulated for three months that was able to seed sPMCA, indicating the accumulation of scrapie-containing material that was independent of the presence of sheep that may have been incubating and possibly shedding low amounts of infectivity.
This study clearly demonstrates the difficulty in removing scrapie infectivity from the farm environment. Practical and effective prion decontamination methods are still urgently required for decontamination of scrapie infectivity from farms that have had cases of scrapie and this is particularly relevant for scrapiepositive goatherds, which currently have limited genetic resistance to scrapie within commercial breeds.24 This is very likely to have parallels with control efforts for CWD in cervids.
Acknowledgements The authors thank the APHA farm staff, Tony Duarte, Olly Roberts and Margaret Newlands for preparation of the sheep pens and animal husbandry during the study. The authors also thank the APHA pathology team for RAMALT and postmortem examination.
Funding This study was funded by DEFRA within project SE1865.
Competing interests None declared.
Saturday, January 5, 2019
Rapid recontamination of a farm building occurs after attempted prion removal
***> CONGRESSIONAL ABSTRACTS PRION CONFERENCE 2018
P69 Experimental transmission of CWD from white-tailed deer to co-housed reindeer
Mitchell G (1), Walther I (1), Staskevicius A (1), Soutyrine A (1), Balachandran A (1)
(1) National & OIE Reference Laboratory for Scrapie and CWD, Canadian Food Inspection Agency, Ottawa, Ontario, Canada.
Chronic wasting disease (CWD) continues to be detected in wild and farmed cervid populations of North America, affecting predominantly white-tailed deer, mule deer and elk. Extensive herds of wild caribou exist in northern regions of Canada, although surveillance has not detected the presence of CWD in this population. Oral experimental transmission has demonstrated that reindeer, a species closely related to caribou, are susceptible to CWD. Recently, CWD was detected for the first time in Europe, in wild Norwegian reindeer, advancing the possibility that caribou in North America could also become infected. Given the potential overlap in habitat between wild CWD-infected cervids and wild caribou herds in Canada, we sought to investigate the horizontal transmissibility of CWD from white-tailed deer to reindeer.
Two white-tailed deer were orally inoculated with a brain homogenate prepared from a farmed Canadian white-tailed deer previously diagnosed with CWD. Two reindeer, with no history of exposure to CWD, were housed in the same enclosure as the white-tailed deer, 3.5 months after the deer were orally inoculated. The white-tailed deer developed clinical signs consistent with CWD beginning at 15.2 and 21 months post-inoculation (mpi), and were euthanized at 18.7 and 23.1 mpi, respectively. Confirmatory testing by immunohistochemistry (IHC) and western blot demonstrated widespread aggregates of pathological prion protein (PrPCWD) in the central nervous system and lymphoid tissues of both inoculated white-tailed deer. Both reindeer were subjected to recto-anal mucosal associated lymphoid tissue (RAMALT) biopsy at 20 months post-exposure (mpe) to the white-tailed deer. The biopsy from one reindeer contained PrPCWD confirmed by IHC. This reindeer displayed only subtle clinical evidence of disease prior to a rapid decline in condition requiring euthanasia at 22.5 mpe. Analysis of tissues from this reindeer by IHC revealed widespread PrPCWD deposition, predominantly in central nervous system and lymphoreticular tissues. Western blot molecular profiles were similar between both orally inoculated white-tailed deer and the CWD positive reindeer. Despite sharing the same enclosure, the other reindeer was RAMALT negative at 20 mpe, and PrPCWD was not detected in brainstem and lymphoid tissues following necropsy at 35 mpe. Sequencing of the prion protein gene from both reindeer revealed differences at several codons, which may have influenced susceptibility to infection.
Natural transmission of CWD occurs relatively efficiently amongst cervids, supporting the expanding geographic distribution of disease and the potential for transmission to previously naive populations. The efficient horizontal transmission of CWD from white-tailed deer to reindeer observed here highlights the potential for reindeer to become infected if exposed to other cervids or environments infected with CWD.
***> Infectious agent of sheep scrapie may persist in the environment for at least 16 years
***> Nine of these recurrences occurred 14–21 years after culling, apparently as the result of environmental contamination,
but outside entry could not always be absolutely excluded.
Gudmundur Georgsson,1 Sigurdur Sigurdarson2 and Paul Brown3
Correspondence
Gudmundur Georgsson ggeorgs@hi.is
1 Institute for Experimental Pathology, University of Iceland, Keldur v/vesturlandsveg, IS-112 Reykjavı´k, Iceland
2 Laboratory of the Chief Veterinary Officer, Keldur, Iceland
3 Bethesda, Maryland, USA
Received 7 March 2006 Accepted 6 August 2006
In 1978, a rigorous programme was implemented to stop the spread of, and subsequently eradicate, sheep scrapie in Iceland. Affected flocks were culled, premises were disinfected and, after 2–3 years, restocked with lambs from scrapie-free areas. Between 1978 and 2004, scrapie recurred on 33 farms. Nine of these recurrences occurred 14–21 years after culling, apparently as the result of environmental contamination, but outside entry could not always be absolutely excluded. Of special interest was one farm with a small, completely self-contained flock where scrapie recurred 18 years after culling, 2 years after some lambs had been housed in an old sheephouse that had never been disinfected. Epidemiological investigation established with near certitude that the disease had not been introduced from the outside and it is concluded that the agent may have persisted in the old sheep-house for at least 16 years.
TITLE: PATHOLOGICAL FEATURES OF CHRONIC WASTING DISEASE IN REINDEER AND DEMONSTRATION OF HORIZONTAL TRANSMISSION
*** DECEMBER 2016 CDC EMERGING INFECTIOUS DISEASE JOURNAL CWD HORIZONTAL TRANSMISSION
SEE;
Back around 2000, 2001, or so, I was corresponding with officials abroad during the bse inquiry, passing info back and forth, and some officials from here inside USDA aphis FSIS et al. In fact helped me get into the USA 50 state emergency BSE conference call way back. That one was a doozy. But I always remember what “deep throat” I never knew who they were, but I never forgot;
Some unofficial information from a source on the inside looking out -
Confidential!!!!
As early as 1992-3 there had been long studies conducted on small pastures containing scrapie infected sheep at the sheep research station associated with the Neuropathogenesis Unit in Edinburgh, Scotland. Whether these are documented...I don't know. But personal recounts both heard and recorded in a daily journal indicate that leaving the pastures free and replacing the topsoil completely at least 2 feet of thickness each year for SEVEN years....and then when very clean (proven scrapie free) sheep were placed on these small pastures.... the new sheep also broke out with scrapie and passed it to offspring. I am not sure that TSE contaminated ground could ever be free of the agent!! A very frightening revelation!!!
---end personal email---end...tss
Infectivity surviving ashing to 600*C is (in my opinion) degradable but infective. based on Bown & Gajdusek, (1991), landfill and burial may be assumed to have a reduction factor of 98% (i.e. a factor of 50) over 3 years. CJD-infected brain-tissue remained infectious after storing at room-temperature for 22 months (Tateishi et al, 1988). Scrapie agent is known to remain viable after at least 30 months of desiccation (Wilson et al, 1950). and pastures that had been grazed by scrapie-infected sheep still appeared to be contaminated with scrapie agent three years after they were last occupied by sheep (Palsson, 1979).
Dr. Paul Brown Scrapie Soil Test BSE Inquiry Document
Using in vitro Prion replication for high sensitive detection of prions and prionlike proteins and for understanding mechanisms of transmission.
Claudio Soto Mitchell Center for Alzheimer's diseases and related Brain disorders, Department of Neurology, University of Texas Medical School at Houston.
Prion and prion-like proteins are misfolded protein aggregates with the ability to selfpropagate to spread disease between cells, organs and in some cases across individuals. I n T r a n s m i s s i b l e s p o n g i f o r m encephalopathies (TSEs), prions are mostly composed by a misfolded form of the prion protein (PrPSc), which propagates by transmitting its misfolding to the normal prion protein (PrPC). The availability of a procedure to replicate prions in the laboratory may be important to study the mechanism of prion and prion-like spreading and to develop high sensitive detection of small quantities of misfolded proteins in biological fluids, tissues and environmental samples. Protein Misfolding Cyclic Amplification (PMCA) is a simple, fast and efficient methodology to mimic prion replication in the test tube. PMCA is a platform technology that may enable amplification of any prion-like misfolded protein aggregating through a seeding/nucleation process. In TSEs, PMCA is able to detect the equivalent of one single molecule of infectious PrPSc and propagate prions that maintain high infectivity, strain properties and species specificity. Using PMCA we have been able to detect PrPSc in blood and urine of experimentally infected animals and humans affected by vCJD with high sensitivity and specificity. Recently, we have expanded the principles of PMCA to amplify amyloid-beta (Aβ) and alphasynuclein (α-syn) aggregates implicated in Alzheimer's and Parkinson's diseases, respectively. Experiments are ongoing to study the utility of this technology to detect Aβ and α-syn aggregates in samples of CSF and blood from patients affected by these diseases.
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***>>> Recently, we have been using PMCA to study the role of environmental prion contamination on the horizontal spreading of TSEs. These experiments have focused on the study of the interaction of prions with plants and environmentally relevant surfaces. Our results show that plants (both leaves and roots) bind tightly to prions present in brain extracts and excreta (urine and feces) and retain even small quantities of PrPSc for long periods of time. Strikingly, ingestion of prioncontaminated leaves and roots produced disease with a 100% attack rate and an incubation period not substantially longer than feeding animals directly with scrapie brain homogenate. Furthermore, plants can uptake prions from contaminated soil and transport them to different parts of the plant tissue (stem and leaves). Similarly, prions bind tightly to a variety of environmentally relevant surfaces, including stones, wood, metals, plastic, glass, cement, etc. Prion contaminated surfaces efficiently transmit prion disease when these materials were directly injected into the brain of animals and strikingly when the contaminated surfaces were just placed in the animal cage. These findings demonstrate that environmental materials can efficiently bind infectious prions and act as carriers of infectivity, suggesting that they may play an important role in the horizontal transmission of the disease.
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Since its invention 13 years ago, PMCA has helped to answer fundamental questions of prion propagation and has broad applications in research areas including the food industry, blood bank safety and human and veterinary disease diagnosis.
New studies on the heat resistance of hamster-adapted scrapie agent: Threshold survival after ashing at 600°C suggests an inorganic template of replication
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Detection of protease-resistant cervid prion protein in water from a CWD-endemic area
A Quantitative Assessment of the Amount of Prion Diverted to Category 1 Materials and Wastewater During Processing
Rapid assessment of bovine spongiform encephalopathy prion inactivation by heat treatment in yellow grease produced in the industrial manufacturing process of meat and bone meals
PPo4-4:
Survival and Limited Spread of TSE Infectivity after Burial
Discussion Classical scrapie is an environmentally transmissible disease because it has been reported in naïve, supposedly previously unexposed sheep placed in pastures formerly occupied by scrapie-infected sheep (4, 19, 20).
Although the vector for disease transmission is not known, soil is likely to be an important reservoir for prions (2) where – based on studies in rodents – prions can adhere to minerals as a biologically active form (21) and remain infectious for more than 2 years (22).
Similarly, chronic wasting disease (CWD) has re-occurred in mule deer housed in paddocks used by infected deer 2 years earlier, which was assumed to be through foraging and soil consumption (23).
Our study suggested that the risk of acquiring scrapie infection was greater through exposure to contaminated wooden, plastic, and metal surfaces via water or food troughs, fencing, and hurdles than through grazing.
Drinking from a water trough used by the scrapie flock was sufficient to cause infection in sheep in a clean building.
Exposure to fences and other objects used for rubbing also led to infection, which supported the hypothesis that skin may be a vector for disease transmission (9).
The risk of these objects to cause infection was further demonstrated when 87% of 23 sheep presented with PrPSc in lymphoid tissue after grazing on one of the paddocks, which contained metal hurdles, a metal lamb creep and a water trough in contact with the scrapie flock up to 8 weeks earlier, whereas no infection had been demonstrated previously in sheep grazing on this paddock, when equipped with new fencing and field furniture.
When the contaminated furniture and fencing were removed, the infection rate dropped significantly to 8% of 12 sheep, with soil of the paddock as the most likely source of infection caused by shedding of prions from the scrapie-infected sheep in this paddock up to a week earlier.
This study also indicated that the level of contamination of field furniture sufficient to cause infection was dependent on two factors: stage of incubation period and time of last use by scrapie-infected sheep.
Drinking from a water trough that had been used by scrapie sheep in the predominantly pre-clinical phase did not appear to cause infection, whereas infection was shown in sheep drinking from the water trough used by scrapie sheep in the later stage of the disease.
It is possible that contamination occurred through shedding of prions in saliva, which may have contaminated the surface of the water trough and subsequently the water when it was refilled.
Contamination appeared to be sufficient to cause infection only if the trough was in contact with sheep that included clinical cases.
Indeed, there is an increased risk of bodily fluid infectivity with disease progression in scrapie (24) and CWD (25) based on PrPSc detection by sPMCA.
Although ultraviolet light and heat under natural conditions do not inactivate prions (26), furniture in contact with the scrapie flock, which was assumed to be sufficiently contaminated to cause infection, did not act as vector for disease if not used for 18 months, which suggest that the weathering process alone was sufficient to inactivate prions.
PrPSc detection by sPMCA is increasingly used as a surrogate for infectivity measurements by bioassay in sheep or mice.
In this reported study, however, the levels of PrPSc present in the environment were below the limit of detection of the sPMCA method, yet were still sufficient to cause infection of in-contact animals.
In the present study, the outdoor objects were removed from the infected flock 8 weeks prior to sampling and were positive by sPMCA at very low levels (2 out of 37 reactions).
As this sPMCA assay also yielded 2 positive reactions out of 139 in samples from the scrapie-free farm, the sPMCA assay could not detect PrPSc on any of the objects above the background of the assay.
False positive reactions with sPMCA at a low frequency associated with de novo formation of infectious prions have been reported (27, 28).
This is in contrast to our previous study where we demonstrated that outdoor objects that had been in contact with the scrapie-infected flock up to 20 days prior to sampling harbored PrPSc that was detectable by sPMCA analysis [4 out of 15 reactions (12)] and was significantly more positive by the assay compared to analogous samples from the scrapie-free farm.
This discrepancy could be due to the use of a different sPMCA substrate between the studies that may alter the efficiency of amplification of the environmental PrPSc.
In addition, the present study had a longer timeframe between the objects being in contact with the infected flock and sampling, which may affect the levels of extractable PrPSc.
Alternatively, there may be potentially patchy contamination of this furniture with PrPSc, which may have been missed by swabbing.
The failure of sPMCA to detect CWD-associated PrP in saliva from clinically affected deer despite confirmation of infectivity in saliva-inoculated transgenic mice was associated with as yet unidentified inhibitors in saliva (29), and it is possible that the sensitivity of sPMCA is affected by other substances in the tested material.
In addition, sampling of amplifiable PrPSc and subsequent detection by sPMCA may be more difficult from furniture exposed to weather, which is supported by the observation that PrPSc was detected by sPMCA more frequently in indoor than outdoor furniture (12).
A recent experimental study has demonstrated that repeated cycles of drying and wetting of prion-contaminated soil, equivalent to what is expected under natural weathering conditions, could reduce PMCA amplification efficiency and extend the incubation period in hamsters inoculated with soil samples (30).
This seems to apply also to this study even though the reduction in infectivity was more dramatic in the sPMCA assays than in the sheep model.
Sheep were not kept until clinical end-point, which would have enabled us to compare incubation periods, but the lack of infection in sheep exposed to furniture that had not been in contact with scrapie sheep for a longer time period supports the hypothesis that prion degradation and subsequent loss of infectivity occurs even under natural conditions.
In conclusion, the results in the current study indicate that removal of furniture that had been in contact with scrapie-infected animals should be recommended, particularly since cleaning and decontamination may not effectively remove scrapie infectivity (31), even though infectivity declines considerably if the pasture and the field furniture have not been in contact with scrapie-infected sheep for several months. As sPMCA failed to detect PrPSc in furniture that was subjected to weathering, even though exposure led to infection in sheep, this method may not always be reliable in predicting the risk of scrapie infection through environmental contamination.
These results suggest that the VRQ/VRQ sheep model may be more sensitive than sPMCA for the detection of environmentally associated scrapie, and suggest that extremely low levels of scrapie contamination are able to cause infection in susceptible sheep genotypes.
Keywords: classical scrapie, prion, transmissible spongiform encephalopathy, sheep, field furniture, reservoir, serial protein misfolding cyclic amplification
Wednesday, December 16, 2015
*** Objects in contact with classical scrapie sheep act as a reservoir for scrapie transmission ***
FRIDAY, DECEMBER 28, 2018
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FRIDAY, JANUARY 11, 2019
TEXAS TAHC Legislative Appropriations Request For Fiscal Years 2018 and 2019 CWD TSE PRION PAY TO PLAY PROGRAM
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***> ADRD Summit RFI Singeltary COMMENT SUBMISSION BSE, SCRAPIE, CWD, AND HUMAN TSE PRION DISEASE December 14, 2018
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Low levels of classical BSE infectivity in rendered fat tissue
FRIDAY, DECEMBER 14, 2018 MAD COW USA FLASHBACK
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***> Variable Protease-Sensitive Prionopathy Transmission to Bank Voles CDC December 14, 2018
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Transmission of amyloid-β protein pathology from cadaveric pituitary growth hormone December 14, 2018
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***> CHILDHOOD EXPOSURE TO CADAVERIC DURA Singeltary et al
Terry S. Singeltary Sr., Bacliff, Texas USA 77518, Galveston Bay...on the bottom...flounder9@verizon.net