Variant CJD 18 years of research and surveillance
Variant CJD
18 years of research and surveillance
Abigail B Diack,Mark W Head,Sandra McCutcheon,Aileen Boyle,Richard Knight,James W Ironside, show all Pages 286-295 | Received 17 Mar 2014, Accepted 14 May 2014, Published online: 01 Nov 2014
Download citation https://doi.org/10.4161/pri.29237 CrossMark
Abstract
It is now 18 years since the first identification of a case of vCJD in the UK. Since that time, there has been much speculation over how vCJD might impact human health. To date there have been 177 case reports in the UK and a further 51 cases worldwide in 11 different countries. Since establishing that BSE and vCJD are of the same strain of agent, we have also shown that there is broad similarity between UK and non-UK vCJD cases on first passage to mice. Transgenic mouse studies have indicated that all codon 129 genotypes are susceptible to vCJD and that genotype may influence whether disease appears in a clinical or asymptomatic form, supported by the appearance of the first case of potential asymptomatic vCJD infection in a PRNP 129MV patient. Following evidence of blood transfusion as a route of transmission, we have ascertained that all blood components and leucoreduced blood in a sheep model of vCJD have the ability to transmit disease. Importantly, we recently established that a PRNP 129MV patient blood recipient with an asymptomatic infection and limited PrPSc deposition in the spleen could readily transmit disease into mice, demonstrating the potential for peripheral infection in the absence of clinical disease. This, along with the recent appendix survey which identified 16 positive appendices in a study of 32 441 cases, underlines the importance of continued CJD surveillance and maintaining control measures already in place to protect human health.
Keywords: prion, variant Creutzfeldt–Jakob disease, transmissible spongiform encephalopathy, prion protein
Introduction Transmissible spongiform encephalopathies (TSE) or prion diseases are a unique group of fatal neurodegenerative diseases occurring in humans and mammals. Prion diseases can be sporadic, heritable, or acquired, they can be transmitted both naturally and experimentally, and as yet, there is no known cure. In 1996, an acquired human prion disease, variant Creutzfeldt–Jakob disease (vCJD), was described in the United Kingdom (UK) leading to a flurry of news reports, changes in government policies regarding the beef industry, a ban on exports of meat, restrictions on blood donations and a widespread fear that anyone could be infected. Since that first report, researchers and health professionals have endeavored to try and understand the disease, identify the infectious agent, assess transmission risks and ultimately improve diagnosis and find a cure. This review will summarize 18 y of research from identification of disease strain, epidemiology, and genetics, to assessing risks of transmission, diagnosis, and therapeutics, and finally the current issues of subclinical disease and ongoing surveillance.
BSE and vCJD: The Same Strain of Agent In 1985, a novel neurodegenerative disease of cattle was recognized in the UK. Pathological examination of the brain material from these cattle suggested that this was a new TSE subsequently named bovine spongiform encephalopathy (BSE).1 A further examination of these cases was performed following transmission of brain material to a panel of wild-type mice. The RIII, C57BL, and VM mice gave similar incubation periods, rankings, and vacuolation profiles for each isolate. Vacuolation distribution in the Prnp-a mice (RIII and C57BL) show distinctive profiles with higher levels or “peak” of vacuolation in the dorsal medulla, hypothalamus, and septum (Fig. 1) whereas Prnp-b mice (VM) show peaks in the dorsal medulla, superior colliculus, thalamus, and septum.2 This BSE signature was confirmed in a number of cases of BSE and was observed in a number of similar transmissions from cats,3 kudu, and nyala.4 Thus confirming a single agent was responsible for these new TSE cases in each species. Furthermore this agent was experimentally transmitted to sheep and goats.5
Figure 1. Vacuolation scoring in the mouse brain. Lesion profile comparison of vCJD and BSE following transmission to RIII mice. Data shows mean lesion profile ± standard error of the mean (n ≥ 6). G1-G9, gray matter scoring regions; (G1) dorsal medulla, (G2) cerebellar cortex, (G3) superior colliculus, (G4) hypothalamus, (G5) thalamus, (G6) hippocampus, (G7) septum, (G8) retrosplenial and adjacent motor cortex, (G9) cingulate and adjacent motor cortex.
Ten years after BSE was recognized, the first case of an atypical form of Creutzfeldt–Jakob disease, termed “new variant CJD” (vCJD) in humans was identified;6 both diseases were recognized to be prion diseases, raising serious concerns that BSE had now spread to humans via consumption of infected meat products.7 Following the same protocols that had been used for the animal transmissions, a series of vCJD transmissions were set up. Initial results published in 1997 using RIII mice indicated that vCJD was indeed caused by the BSE agent.8 At the same time, Hill et al.9 showed similar results using FVB mice. Further studies have shown that incubation period rankings, lesion profiles and abnormal prion protein (PrPSc) deposition patterns are all identical to the BSE agent (Figs. 1 and 2).10,11 The definitive evidence that BSE and vCJD were the same strain came with the characterization of primary and secondary transmission of 10 cases of vCJD to mice. In this study both CNS and peripheral material was transmitted and showed that in all cases transmission characteristics were similar to BSE.12 To date, all cases of UK 129MM (methionine homozygous) vCJD that have been characterized have shown similar strain characteristics to BSE.
Figure 2. Abnormal PrP deposition in hippocampus of RIII and VM mice following inoculation with BSE or vCJD. (A) BSE in RIII mouse; (B) vCJD in RIII mouse; (C) BSE in VM mouse; (D) vCJD in VM mouse (bar, 100 μm; anti-PrP antibody: 6H4).
In addition to epidemiological, neuropathological, and biological evidence, the biochemical analysis of PrPSc deposited in both the BSE brain and vCJD brain also supports a link between the agents responsible. Western blotting of partially protease-resistant prion protein provides a surrogate for conformation and/or aggregation state and also reflects glycosylation site occupancy in the form of (generally 3) bands of protease-resistant prion protein (PrPres) of defined mobility (determined by N-terminal truncation) and relative abundance (determined by glycosylation). Using this method BSE can be differentiated from most forms of sheep scrapie.13 Similarly vCJD can be distinguished from other human prion diseases, in particular sporadic CJD (sCJD),14,15 whereas BSE and vCJD share both mobility type and have a similar glycoform ratio.14 This BSE/vCJD PrPres type (referred to a type 2B or type 4) appears to be closely associated with the agent since (1) it also characterizes the PrPres that accumulates in peripheral tissues in clinical vCJD,16 (2) it is maintained following secondary transmission of vCJD by blood transfusion both in the brain of clinical cases,17 and in the spleen of asymptomatic or preclinical individuals,18,19 (3) it is largely stable on transmission to wild-type and humanised transgenic mice12,20 and (4) it is maintained in cell-free conversion systems in which either BSE or vCJD brain homogenates are used to seed conversion of normal human prion protein.21
While type 2B PrPres provides a convenient additional diagnostic tool for human BSE identification,22 it does not provide a complete description of PrPSc in cases of vCJD, nor does it provide a biochemical definition of the agent. The largest amount of PrPSc in the vCJD brain is actually protease sensitive23 and therefore does not figure in conventional PrPres typing. Even within the protease-resistant fraction of vCJD PrPSc there is evidence of a minority PrPres type.24 The use of assays that do not depend upon protease-resistance as a definition of PrPSc show that aggregation state and stability are additional biochemical parameters that may be relevant to neurotoxicity and agent replication.25,26
vCJD in the UK and Beyond Since the first recorded case of vCJD in 1996, 177 cases of definite or probable vCJD have been reported in the UK (as of April 2014). The annual number of deaths reached a peak in 2000 with 28 deaths but since 2006, deaths from vCJD have levelled off at 2–5 per year with none reported in 2012 and only one in 201327 (Fig. 3). Originally restricted to the UK, 51 cases have now been reported in 11 other countries with a worldwide total of 228 (Fig. 3). Outside of the UK, most cases have occurred in France (27 cases to date) and are thought to be related to the peak in volume of beef imports originating from the UK during 1985–1995.28 This potential relationship is shown in the peak in number of deaths from vCJD in France in 2005, 5 y after a similar peak in the UK.28,29 Further evidence of the link between UK and French vCJD has arisen from comparative studies comparing epidemiologic, clinical, pathological, and biochemical analyses of vCJD cases from both countries indicating that the same strain of agent could be responsible.30 The type 2B PrPres that characterizes UK vCJD cases15 is also present in vCJD patients from France30 and cases from Holland, Portugal, Spain, and Italy (Head and Ironside, unpublished information), consistent with the same strain of agent being involved in these different countries.
Figure 3. Reported incidence of vCJD deaths in the UK and in non-UK countries.
Exports of UK meat or cattle are assumed to have played a major role in the incidence of vCJD cases in other countries;31 however there is the possibility that indigenous BSE or another strain of agent is responsible. In order to assess whether the same strain of agent is responsible for all vCJD cases worldwide, Diack et al.32 performed strain typing of French, Italian, Dutch, and American cases of vCJD. These were all of the 129MM genotype and with limited exposure to UK BSE. Analysis of the transmission properties showed that the non-UK cases shared the same characteristics as UK cases of vCJD, however small differences were apparent in the incubation period rankings which are currently being studied.32 The similar characteristics between UK and non-UK cases of vCJD suggest that current diagnostic criteria are sufficient to detect cases in all countries at this time. However these studies characterized “typical” cases of vCJD and do not take into account atypical cases or those occurring in genotypes other than 129MM.
All Codon 129 Genotypes are Susceptible to vCJD Mutations and polymorphisms in the prion protein gene (PRNP) can influence or be associated with disease, i.e., E200K-129M in genetic CJD or A117V-129V in Gerstman–Sträussler–Scheinker disease (GSS). The codon 129 polymorphism (methionine (M)-valine (V)) of PRNP is known to be associated with susceptibility to CJD33 with evidence from studies of kuru suggesting that heterozygosity is associated with increased survival times.34 As stated, all definite and probable cases of clinical vCJD have been of the 129MM genotype which is in contrast to the normal distribution of genotypes in the general UK population; 42% 129MM, 47% 129MV, and 11% 129VV35 and is suggestive of an association between vCJD susceptibility and genotype.
Experimental transmission studies have utilized gene targeted mice expressing human PrPC at physiological levels and overexpression models carrying each of the codon 129 genotypes to reveal that human-to-human transmission of vCJD is possible and that all genotypes have the potential to be affected.9,20,36 Bishop et al.20 used gene targeted models allowing direct comparison between mouse lines; these studies showed that transmission efficiency varied in the order MM > MV > VV with different pathological characteristics for each genotype. Mice expressing 129MM (HuMM) showed the greatest transmission efficiency and the earliest onset of both clinical disease and TSE related pathology. Although fewer HuMV mice were clinically affected and showed an extended incubation period, similar numbers demonstrated evidence of PrPSc compared with HuMM mice. In contrast only one HuVV mouse showed evidence of PrPSc.20 This pattern of susceptibility has been repeated in a series of vCJD transmissions both from UK and non-UK material. This data suggests that in humans not only do all genotypes have the potential to be affected but that the different genotypes may manifest disease in different ways and indeed 129MV and 129VV individuals may have long asymptomatic incubation periods.
The evidence from the mouse studies has been shown in humans by the discovery of PrPSc in an asymptomatic PrP codon 129 heterozygote individual who died of a non-neurological disorder 5 y after receiving blood from an individual who later went onto develop clinical vCJD. In this individual evidence of PrPSc was found in the spleen and a cervical lymph node.19 Transmission studies have now shown the spleen from this individual to be infectious.37 A possible case of vCJD in a 129MV individual was reported in 2009, however vCJD was not confirmed since no autopsy was undertaken.38 Additionally, retrospective studies of anonymised tonsil and appendix samples have shown evidence of PrPSc in all 3 genotypes giving further support to the evidence that all genotypes are susceptible to vCJD.39,40
Modeling human genetic susceptibility to BSE using cell-free assays confirms the importance of methionine at codon 129 of the PRNP gene as a susceptibility factor, and shows the conversion efficiency to be MM > MV > VV, irrespective of whether the brain homogenate used to seed the reaction is vCJD, cattle BSE or experimental sheep BSE.21
Blood as a Route of Transmission of vCJD The UK shows the highest incidence of vCJD in the world.27 At early stages of the epidemic, it was largely accepted that there was a minimal risk of transmission of vCJD from donations of peripheral blood/tissue from affected individuals to others via iatrogenic routes. That said great efforts were made to trace and track the fate of blood components used for transfusion from donors known to have vCJD.41 Concomitantly, the likelihood of transmission of prion infection through blood, either by inoculation or transfusion and the distribution of prion-associated infectivity in blood components was being assessed using a range of animal models, typically small animal models.42-48 These produced estimates of ∼10 infectious doses (ID)/ml in hamster blood.47,49 Rodent models do not however represent accurately the procedures used in a clinical setting for blood transfusion. Large animal models such as sheep or deer infected with BSE or scrapie provide a suitable alternative to better assess the likelihood of transmission of prion disease following exposure by blood transfusion.50-52 Larger volumes of blood can be collected from such animals and processed into components with similar specifications as those used for transfusion to humans.53 Furthermore the peripheral pathogenesis of scrapie and BSE in sheep closely resembles that of humans affected with vCJD.54,55 Over a decade ago, transfusion studies in sheep first demonstrated that all clinically-relevant blood components collected at both preclinical and clinical time points contained sufficient titers of disease-associated infectivity and could be transmitted to recipients after a single transfusion event. Moreover, the number of recipients that developed disease was suggestive that blood transfusion was a highly efficient route by which prion diseases could be transmitted.56 Of note, in this and other studies, was the finding that the process of leucoreduction alone did not prevent the transmission of prion disease following blood transfusion.49,53 The relevance of the latter point being that all components used for blood transfusion in humans are subject to universal leucoreduction. Data showing that blood from prion-infected animals was infectious was confirmed by other research groups using sheep57,58 and deer blood transfusion models.59-61
Since the late 1990s a number of risk reduction strategies were implemented to safeguard the UK blood (and blood product) supply. This included donor deferral and exclusion, importation of plasma from the USA for the preparation of plasma derivatives, i.e., clotting factors; the use of disposal instruments for certain surgical and dental procedures; and universal leucoreduction of all components used for transfusion.62 Following a further risk assessment initiated by the Department of Health, selected groups of patients were informed that they could be considered to have a “small increased risk of carrying the vCJD agent” following receipt of certain batches of plasma products. These groups included hemophiliacs and those affected with other bleeding disorders and those with primary or secondary immunodeficiencies.62,63
It was not until 2004 that blood from vCJD-infected humans was shown to pose a significant risk of acquiring prion infection. This followed the identification of 2 potential cases of blood-transfusion acquired vCJD.19,64 A few years later saw the identification of another case of apparent transfusion-acquired vCJD.65 These data were collated and cases presented in detail in 2006.41,66 A fourth occurrence of transfusion-acquired vCJD was subsequently identified and all cases have been summarized in a recent review.67 The 4 affected individuals were from the UK and all received non-leucoreduced red cell concentrates from UK donors, who were asymptomatic of infection at the time of donation but later died from vCJD. The transfusions took place between 1996 and 1999. Of the 4 transfusion recipients, 3 developed a clinical infection consistent with previously identified cases of vCJD (i.e., diseased-associated prion protein was evident in brain and peripheral lymphoid tissues examined post-mortem).17 These individuals were identified as being methionine homozygous at codon 129 in the PRNP gene. The remaining transfusion recipient showed no clinical signs associated with vCJD or other neurological-type conditions and there was no evidence of disease-associated prion protein in the individual's brain and indeed the patient died of causes unrelated to vCJD.19 Disease-associated prion protein was identified in selected lymphoid tissues such as the spleen and a cervical lymph node. Unlike the 3 clinical cases previously reported, this recipient was identified as having a different PRNP genotype being heterozygous (MV) at codon 129.
A surveillance program (established by the National CJD Research and Surveillance Unit and the UK Hemophilia Centre Doctors Organisation) identified the first case of vCJD infection in a hemophiliac patient.18,68,69 The study examined biopsy and autopsy samples of lymphoid or brain tissue from a small numbers of samples submitted for investigation. The individual was an elderly male who resided in the UK. In conjunction with surgical procedures, the patient received numerous units of non-leucoreduced red cells and thousands of units of Factor VIII. The factor VIII was prepared from UK plasma pools and it was found that some of the pooled-plasma could be traced back to a donor who died from vCJD. The individual showed no signs of vCJD or other neurological conditions and was MV at codon 129 in the PRNP gene. Upon repeated examination, a specific area of spleen was positive for the abnormal form of the prion protein. A subsequent risk assessment found that of all possible sources of vCJD infection, including dietary exposure, the mostly likely was determined as treatment with UK-sourced clotting factors.70 To date, there have been no further cases of vCJD acquired following the transfusion of blood, blood components or clotting factors. While there has been no documented evidence, to date, of the transmission of sCJD infection following blood transfusion in humans,41 a recent, though limited study, has reported the presence of disease-associated infectivity in plasma obtained from 2 patients affected with sCJD.71
Although estimates of the infectious titer of blood from patients with vCJD are low71,72 it has been demonstrated that blood and components from asymptomatic individuals appear capable of transmitting vCJD-infection following blood transfusion. Major efforts have been made toward the development of screening assays and diagnostic tests for vCJD in blood72-75; the development and implementation of prion reduction filters76-80; understanding the numbers of individuals who may be sub-clinically affected with vCJD39,81-84 and what this really means in terms of further spread of vCJD. There are significant challenges to be faced in each of these areas, which are further confounded by the absence of an available treatment for vCJD.
Prevalence of Asymptomatic vCJD Infection The UK population had a wide exposure to the BSE agent through contaminated meat products in the food chain in the 1980s and early 1990s, resulting in 177 definite cases of vCJD to date. Of the cases genotyped, all were methionine homozygotes at codon 129 in the PRNP gene. However there are ongoing concerns over vCJD infection in other codon 129 genotypes with potentially longer incubation periods. This has prompted a series of tissue–based studies on the prevalence of vCJD infection in lymphoid tissues (appendices and tonsils) removed surgically as part of treatment for appendicitis, tonsillitis, and related disorders in otherwise healthy individuals with no neurological symptoms. Variant CJD differs from other human prion diseases in the widespread involvement of lymphoid tissues by the causative agent which is detectable in follicular dendritic cells and is associated with infectivity.16,85
Review of paraffin-embedded appendices that had been resected from a small number of individuals before the onset of vCJD revealed that prion protein was detectable in the lymphoid follicles in the wall of the appendix for at least 2 y prior to the onset of vCJD symptoms.86 This observation allowed the possibility of a large-scale retrospective survey of appendix and tonsil tissues from histopathology departments across the UK to determine the extent of asymptomatic vCJD infection as revealed by immunohistochemistry on paraffin-embedded tissues. These studies have proven challenging in terms of logistics and ethics and have proceeded on the basis of using anonymised specimens that are not directly linkable to any individual. The first of these studies reported in 2004 an estimated prevalence of asymptomatic vCJD infection in 237 per million in 4000 individuals in the UK (3 in 12 674 positive specimens tested), but with very wide 95% confidence intervals (49–692 per million).83 Two subsequent prospective studies on tonsil tissues collected frozen tissue samples as well as paraffin-embedded tissues, which allowed the use of enzyme immunoassays and western blotting in addition to immunohistochemistry for the detection of the abnormal prion protein.81,82,87 No positives were detected in the frozen tissue samples from either study (2000 in Frosh et al.87; 32 661 in Clewley et al,81). Immunohistochemistry was subsequently performed on 10 075 samples from the de Marco et al.82 study, with 1 apparent positive detected.
In order to resolve the findings from these studies, a larger unlinked and anonymised immunohistochemical survey was performed on archived paraffin-embedded appendix samples from 41 histopathology departments in the UK.39 Of the 32 441 samples assessed, 16 were positive for abnormal prion protein, giving an overall prevalence of 493 per million (95% confidence intervals 282–801 per million), which is broadly in keeping with the results of the earlier study by Hilton et al.83 PRNP codon 129 genotype analysis of the positive cases showed that all possible genotypes were involved, with a predominance of the valine homozygous genotype,39 as for the Hilton et al. study,40 and in contrast with the definite cases of vCJD identified to date. These findings have a wide range of implications, including the need for continuing surveillance of human prion diseases in the UK and the risks of secondary vCJD transmission from asymptomatic infected individuals via surgical instruments or blood transfusion; the latter is now the subject of a UK Parliamentary Inquiry (Parliamentary Select Committee on Science and Technology, 201388).
Diagnostics and Treatment The diagnosis of vCJD rests on recognizing the typical phenotype and applying appropriate specialist investigations, in particular MRI brain scan (Fig. 4). The clinical features are remarkably stereotyped. There is an initial phase of around 6 mo dominated by psychiatric symptoms, including depression, delusions, and anxiety89 followed by the rapid development of neurological features,90 typically confusion, ataxia, and involuntary movements, which may be choreiform, dystonic, or myoclonic. The duration of illness from onset to death averages 14 mo91 in contrast to sCJD in which the mean survival is 4 mo.
Figure 4. MRI brain scan in variant CJD. FLAIR axial section at the level of the basal ganglia showing bilateral symmetrical dorsomedial and pulvinar thalamic hyperintensity. Courtesy of Dr David Summers.
The electroencephalogram does not show the periodic sharp wave complexes that are seen in sCJD, except rarely in the terminal stages of the illness92 and the CSF 14–3-3 immunoassay is only positive in about half the cases.93 The CSF RT-QuIC has been negative in vCJD in all assays to date. The most helpful investigation is MRI brain scan, which shows high signal in the pulvinar region of the thalamus, the so-called hockey stick sign, on FLAIR (Fig. 4) and DWI sequences in over 90% of cases.94 Tonsil biopsy shows immunostaining and deposition of type 2B or type 4 PrPres in the majority of cases,95,96 but this test is invasive, and definitive diagnosis rests on neuropathological examination of brain tissue, usually at post-mortem.
Highly sensitive and specific diagnostic criteria, including a combination of core clinical features and the results of MRI brain scan and pathology, have been formulated97 and validated.98 Cases classified as definite or probable are reported by international surveillance systems as the likelihood of accurate diagnosis in possible cases is uncertain.
The phenotype in cases of vCJD in an MV or VV genetic background cannot be predicted and continued vigilance is necessary in order to identify such cases.
Treatment of vCJD has been attempted using a range of medications, but none have been proven to be effective. Initial reports of improvement following treatment with quinacrine have not been confirmed in observational trials99,100 and this drug is no longer used in vCJD treatment. Studies in animal models raised the possibility that pentosan polysulphate (PPS) might be a candidate treatment for vCJD101 and extended survival has been reported in a small number of treated cases.102,103 However, this medication has to be given by intraventricular infusion, requiring a neurosurgical procedure, and treated patients continued to decline with no reversal of severe neurological deficits.104 Post-mortem examination of one case of vCJD treated with PPS showed extensive and severe pathology.105 Some cases of vCJD received doxycycline with no obvious benefit and a controlled trial in sCJD has not demonstrated efficacy.99
Emergence of Novel Strains Identification of novel strains involves veterinary and medical vigilance, but it also requires a proper and full characterization of known prion agents. While the deployment of wild-type mouse panels, transgenic mice, and non-human primates all rapidly concluded that vCJD was a novel human prion strain related to BSE (see above), determining how many distinct human prion strains there are has proved surprisingly difficult, especially for sCJD. Transmission studies in humanised transgenic mice and non-human primates point to 4 major groups within sporadic, iatrogenic CJD, Kuru, and some genetic CJD cases, termed M1, V1, M2, and V2.22,106 Sporadic fatal insomnia and fatal familial insomnia (FFI) together may represent a sixth strain107 and 2 further transmissible phenotypes can be derived from GSS disease: one involving a transmissible amyloid phenotype, the other a fully transmissible spongiform encephalopathy.108,109 The transmission properties of PrP cerebral amyloid angiopathy and Variably ProteaseSensitive Prionopathy (VPSPr) remain to be reported. The relationship between human disease phenotypes, agent strain, and prion biochemistry is further complicated by the now widely recognized phenomenon of distinct PrPres type co-occurrence in the sCJD, vCJD and VPSPr brain.15,24,110
Surveillance for BSE in cattle, sheep, and goats has identified new (or newly discovered) animal prion diseases including atypical scrapie in sheep and so called H- and L-type BSE in cattle. These along with chronic wasting disease (CWD) in deer and elk represent a potential zoonotic risk to human health that is hard to quantify. While Wilson et al.111 have shown no transmission of CWD, BASE, H-type BSE, and atypical scrapie to mice expressing wild-type levels of human PrP, Kong et al.112 demonstrated transmission of BASE to an alternative line of mice expressing wild-type levels of human PrP. In contrast, Beringue et al.113 showed transmission of BASE to mice overexpressing human PrP but no evidence of H-type BSE transmission, furthermore no evidence of CWD transmission to overexpressing mice has been identified.114,115 This difference in transmission results may be due to different genetic backgrounds or differences in PrP expression levels between the different mouse lines. An alternative to modeling the species barrier is the cell-free conversion assay which points to CWD as the animal prion disease with the greatest zoonotic potential, after (and very much less than) BSE.116Barria MA, Balachandran A, Morita M, Kitamoto T, Barron R, Manson J, Knight R, Ironside JW, Head MW. Molecular barriers to zoonotic transmission of prions. Emerg Infect Dis 2014; 20:88-97; PMID:24377702; http://dx.doi.org/10.3201/eid2001.130858 [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]
Surveillance Continued surveillance for long-term effects of BSE exposure in the UK human population appears necessary for the foreseeable future in order to discount possible second wave epidemics that might depend on genetic susceptibility, subclinical infection, and secondary transmission or disease in defined “at risk” patient groups such as hemophiliacs or patient groups in which full ascertainment is difficult, such as the elderly.
However, an additional concern is associated with idiopathic human prion disease. Sporadic CJD is not a uniform condition and the phenotype is clearly influenced by the codon 129 genotype of the patient and the prion protein type that accumulates in their brain. The etiological basis of the condition might be presumed to be spontaneously occurring, but this is not known with certainty in general, or in individual specific cases. Neither are the molecular mechanisms of spontaneous conversion of the prion protein to its pathogenic form well understood or easily investigated. Additionally, surveillance identifies apparently sporadic cases of human prion disease that do not fit well into currently accepted classification systems. This is exemplified by the recent identification of a new human prion disease (VPSPr by Gambetti et al.117) and its prospective and retrospective identification in other countries subsequently.118,110 The true prevalence, the relationship to sCJD and the risk to public health of VPSPr are yet to be determined.
Conclusions Since the identification of vCJD we have made progress in identifying routes of infection, controlling further infection, producing models of disease, developing decontamination procedures, and understanding susceptibility to disease. The vCJD epidemic in the UK now appears to be in decline and it appears that the control measures in food production and blood supplies have prevented further vCJD cases arising through dietary/infected blood exposure.
Despite this, there are still ongoing concerns over cases of vCJD arising in countries where little or no exposure to UK meat products have occurred, the presence of subclinical vCJD in the UK population with the possibility of further human-to-human transmission and the identification of new strains of human prion disease. These scenarios necessitate ongoing studies in understanding transmission properties, disease diagnosis, and therapeutics. The identification of novel human prion diseases and the current estimates of subclinical vCJD infections show the importance of continued CJD surveillance and maintaining control measures already in place to protect human health.
Disclosure of Potential Conflicts of Interest No potential conflicts of interest were disclosed.
Acknowledgments We are grateful to our colleagues at The Roslin Institute, the National CJD Research and Surveillance Unit, and the Edinburgh Brain Bank for help in these studies.
Funding The work described here has been supported by BBSRC, Medical Research Council, and Department of Health. This report is independent research commissioned and funded by the Department of Health, Policy Research Programme. The views expressed in this publication are those of the authors and not necessarily those of the Department of Health.
References
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Saturday, November 23, 2019
Prion disease incidence in the United States, 2003–2015
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Article (citation):
. Prion disease incidence in the United States, 2003–2015. Neurology (2019); 10.1212/WNL.0000000000008680
https://n.neurology.org/content/early/2019/11/22/WNL.0000000000008680
The comment "RE: Prion disease incidence in the United States, 2003–2015" was submitted on 23 11 2019:
Greetings Neurology et al, I still find this hard to believe, especially with the new sporadic cjd called vpspr in humans, and the other new tse prion disease popping up in humans, along with the poor surveillance we have from state to state for human tse prion. with this continued belief of the UK BSE nvCJD only theory, meaning only those few tied to the typical C-BSE strain in cattle as nvCJD in humans, or what they call today vCJD, and that no other human tse on the globe is from any other animal tse prion like cwd tse prion in cervid, scrapie in sheep and goats, or the other atypical bse tse in cattle, and what about the outbreak of a new tse prion in a new livestock species, the camel. i think this belief, and continued statements of such (without reading the full study, i have no access as a peon), i believe helps continue to spread the tse prion around the globe, by ignoring the fact that all iatrogenic CJD is, is sporadic CJD, until the iatrogenic event is discovered, proven, documented, put in to the academic domain, and finally in the public domain. now we know that cwd in cervid and scrapie can transmit to pigs by oral route, and we also know out mad cow feed ban was a colossal failure. i also remember what some of these same scientist said long ago on this topic and cwd being zoonosis or not, and this was 2002, since then much science has come forth showing that cwd to humans not only is very probable, it most likely has already happened. we have doctors and scientist still claiming that 85%+ all human tse prion disease i.e. the sporadic cjd is a spontaneous event from nothing, just a funked out protein that twist wrongly, and that no other reason exist, and this is a dangerous precedent to set, without proof, and will continue to help spread the tse prion imo...
see;
Saturday, November 23, 2019 Prion disease incidence in the United States, 2003–2015
November 22, 2019
ARTICLE
Prion disease incidence in the United States, 2003–2015
Ryan A. Maddox, Marissa K. Person, Janis E. Blevins, Joseph Y. Abrams, Brian S. Appleby, Lawrence B. Schonberger, Ermias D. Belay
Ryan A. Maddox, PhD, Marissa K. Person, MSPH, Janis E. Blevins, Joseph Y. Abrams, PhD, Brian S. Appleby, MD, Lawrence B. Schonberger, MD and Ermias D. Belay, MD
+Ryan A. Maddox, PhD, +Marissa K. Person, MSPH, +Janis E. Blevins, +Joseph Y. Abrams, PhD, +Brian S. Appleby, MD, +Lawrence B. Schonberger, MD and +Ermias D. Belay, MD
From the National Center for Emerging and Zoonotic Infectious Diseases (R.A.M., M.K.P., J.Y.A., L.B.S., E.D.B.), Centers for Disease Control and Prevention, Atlanta, GA; and National Prion Disease Pathology Surveillance Center (J.E.B., B.S.A.), Case Western Reserve University, Cleveland, OH.
Correspondence Dr. Maddox rmaddox@cdc.gov
First published November 22, 2019, DOI: https://doi.org/10.1212/WNL.0000000000008680
Abstract
Objective
To report the incidence of prion disease in the United States.
Methods
Prion disease decedents were retrospectively identified from the US national multiple cause-of-death data for 2003–2015 and matched with decedents in the National Prion Disease Pathology Surveillance Center (NPDPSC) database through comparison of demographic variables. NPDPSC decedents with neuropathologic or genetic test results positive for prion disease for whom no match was found in the multiple cause-of-death data were added as cases for incidence calculations; those with cause-of-death data indicating prion disease but with negative neuropathology results were removed. Age-specific and age-adjusted average annual incidence rates were then calculated.
Results
A total of 5,212 decedents were identified as having prion disease, for an age-adjusted average annual incidence of 1.2 cases per million population (range 1.0 per million [2004 and 2006] to 1.4 per million [2013]). The median age at death was 67 years. Ten decedents were <30 2="" 5.9="" 6.2="" age="" among="" annual="" average="" billion="" cases="" disease.="" div="" forms="" incidence="" million.="" of="" only="" per="" prion="" sporadic="" these="" those="" very="" was="" were="" years="" young="">
Conclusions
Prion disease incidence can be estimated by augmenting mortality data with the results of neuropathologic and genetic testing. Cases <30 a="" age="" all="" and="" attributed="" be="" continued="" could="" diseases="" div="" exogenous="" extremely="" factors="" for="" genetic="" groups="" in="" most="" mutation.="" of="" or="" presence="" prion="" prudent.="" rare="" remains="" the="" to="" vigilance="" were="" years="">
Received November 16, 2018. Accepted in final form July 9, 2019. © 2019 American Academy of Neurology
January 28, 2003; 60 (2) VIEWS & REVIEWS
Monitoring the occurrence of emerging forms of Creutzfeldt-Jakob disease in the United States
Ermias D. Belay, Ryan A. Maddox, Pierluigi Gambetti, Lawrence B. Schonberger
First published January 28, 2003, DOI: https://doi.org/10.1212/01.WNL.0000036913.87823.D6
Abstract
Transmissible spongiform encephalopathies (TSEs) attracted increased attention in the mid-1980s because of the emergence among UK cattle of bovine spongiform encephalopathy (BSE), which has been shown to be transmitted to humans, causing a variant form of Creutzfeldt-Jakob disease (vCJD). The BSE outbreak has been reported in 19 European countries, Israel, and Japan, and human cases have so far been identified in four European countries, and more recently in a Canadian resident and a US resident who each lived in Britain during the BSE outbreak. To monitor the occurrence of emerging forms of CJD, such as vCJD, in the United States, the Centers for Disease Control and Prevention has been conducting surveillance for human TSEs through several mechanisms, including the establishment of the National Prion Disease Pathology Surveillance Center. Physicians are encouraged to maintain a high index of suspicion for vCJD and use the free services of the pathology center to assess the neuropathology of clinically diagnosed and suspected cases of CJD or other TSEs.
Received May 7, 2002. Accepted August 28, 2002.
RE-Monitoring the occurrence of emerging forms of Creutzfeldt-Jakob disease in the United States
Terry S. Singeltary, retired (medically)
Published March 26, 2003
26 March 2003
Terry S. Singeltary, retired (medically) CJD WATCH
I lost my mother to hvCJD (Heidenhain Variant CJD). I would like to comment on the CDC's attempts to monitor the occurrence of emerging forms of CJD. Asante, Collinge et al [1] have reported that BSE transmission to the 129-methionine genotype can lead to an alternate phenotype that is indistinguishable from type 2 PrPSc, the commonest sporadic CJD. However, CJD and all human TSEs are not reportable nationally. CJD and all human TSEs must be made reportable in every state and internationally. I hope that the CDC does not continue to expect us to still believe that the 85%+ of all CJD cases which are sporadic are all spontaneous, without route/source. We have many TSEs in the USA in both animal and man. CWD in deer/elk is spreading rapidly and CWD does transmit to mink, ferret, cattle, and squirrel monkey by intracerebral inoculation. With the known incubation periods in other TSEs, oral transmission studies of CWD may take much longer. Every victim/family of CJD/TSEs should be asked about route and source of this agent. To prolong this will only spread the agent and needlessly expose others. In light of the findings of Asante and Collinge et al, there should be drastic measures to safeguard the medical and surgical arena from sporadic CJDs and all human TSEs. I only ponder how many sporadic CJDs in the USA are type 2 PrPSc?
Reply to Singletary Ryan A. Maddox, MPH Other Contributors: Published March 26, 2003
Mr. Singletary raises several issues related to current Creutzfeldt- Jakob disease (CJD) surveillance activities. Although CJD is not a notifiable disease in most states, its unique characteristics, particularly its invariably fatal outcome within usually a year of onset, make routine mortality surveillance a useful surrogate for ongoing CJD surveillance.[1] In addition, because CJD is least accurately diagnosed early in the course of illness, notifiable-disease surveillance could be less accurate than, if not duplicative of, current mortality surveillance.[1] However, in states where making CJD officially notifiable would meaningfully facilitate the collection of data to monitor for variant CJD (vCJD) or other emerging prion diseases, CDC encourages the designation of CJD as a notifiable disease.[1] Moreover, CDC encourages physicians to report any diagnosed or suspected CJD cases that may be of special public health importance (e.g...., vCJD, iatrogenic CJD, unusual CJD clusters).
As noted in our article, strong evidence is lacking for a causal link between chronic wasting disease (CWD) of deer and elk and human disease,[2] but only limited data seeking such evidence exist. Overall, the previously published case-control studies that have evaluated environmental sources of infection for sporadic CJD have not consistently identified strong evidence for a common risk factor.[3] However, the power of a case-control study to detect a rare cause of CJD is limited, particularly given the relatively small number of subjects generally involved and its long incubation period, which may last for decades. Because only a very small proportion of the US population has been exposed to CWD, a targeted surveillance and investigation of unusual cases or case clusters of prion diseases among persons at increased risk of exposure to CWD is a more efficient approach to detecting the possible transmission of CWD to humans. In collaboration with appropriate local and state health departments and the National Prion Disease Pathology Surveillance Center, CDC is facilitating or conducting such surveillance and case- investigations, including related laboratory studies to characterize CJD and CWD prions.
Mr. Singletary also expresses concern over a recent publication by Asante and colleagues indicating the possibility that some sporadic CJD cases may be attributable to bovine spongiform encephalopathy (BSE).[4] The authors reported that transgenic mice expressing human prion protein homozygous for methionine at codon 129, when inoculated with BSE prions, developed a molecular phenotype consistent with a subtype of sporadic CJD. Although the authors implied that BSE might cause a sporadic CJD-like illness among persons homozygous for methionine, the results of their research with mice do not necessarily directly apply to the transmission of BSE to humans. If BSE causes a sporadic CJD-like illness in humans, an increase in sporadic CJD cases would be expected to first occur in the United Kingdom, where the vast majority of vCJD cases have been reported. In the United Kingdom during 1997 through 2002, however, the overall average annual mortality rate for sporadic CJD was not elevated; it was about 1 case per million population per year. In addition, during this most recent 6-year period following the first published description of vCJD in 1996, there was no increasing trend in the reported annual number of UK sporadic CJD deaths.[3, 5] Furthermore, surveillance in the UK has shown no increase in the proportion of sporadic CJD cases that are homozygous for methionine (Will RG, National CJD Surveillance Unit, United Kingdom, 2003; personal communication)..
References
1. Gibbons RV, Holman RC, Belay ED, Schonberger LB. Diagnosis and reporting of Creutzfeldt-Jakob disease. JAMA 2001;285:733-734.
2. Belay ED, Maddox RA, Gambetti P, Schonberger LB. Monitoring the occurrence of emerging forms of Creutzfeldt-Jakob disease in the United States. Neurology 2003;60:176-181.
3. Belay ED. Transmissible spongiform encephalopathies in humans. Annu Rev Microbiol 1999;53:283-314.
4. Asante EA, Linehan JM, Desbruslais M, et al. BSE prions propagate as either variant CJD-like or sporadic CJD-like prion strains in transgenic mice expressing human prion protein. EMBO J 2002;21:6358-6366.
5. The UK Creutzfeldt-Jakob Disease Surveillance Unit. CJD statistics. Available at: http://www.cjd.ed.ac.uk/figures.htm. Accessed February 18, 2003.
Competing Interests: None declared.
-------- Original Message --------
Subject: re-BSE prions propagate as either variant CJD-like or sporadic CJD
Date: Thu, 28 Nov 2002 10:23:43 -0000 From: "Asante, Emmanuel A" To: "'flounder@wt.net'"
Dear Terry,
I have been asked by Professor Collinge to respond to your request. I am a Senior Scientist in the MRC Prion Unit and the lead author on the paper. I have attached a pdf copy of the paper for your attention. Thank you for your interest in the paper.
In respect of your first question, the simple answer is, yes. As you will find in the paper, we have managed to associate the alternate phenotype to type 2 PrPSc, the commonest sporadic CJD. It is too early to be able to claim any further sub-classification in respect of Heidenhain variant CJD or Vicky Rimmer's version. It will take further studies, which are on-going, to establish if there are sub-types to our initial finding which we are now reporting. The main point of the paper is that, as well as leading to the expected new variant CJD phenotype, BSE transmission to the 129-methionine genotype can lead to an alternate phenotype which is indistinguishable from type 2 PrPSc.
I hope reading the paper will enlighten you more on the subject. If I can be of any further assistance please to not hesitate to ask. Best wishes.
Emmanuel Asante
<>
____________________________________
Dr. Emmanuel A Asante MRC Prion Unit & Neurogenetics Dept. Imperial College School of Medicine (St. Mary's) Norfolk Place, LONDON W2 1PG Tel: +44 (0)20 7594 3794 Fax: +44 (0)20 7706 3272 email: e.asante@ic.ac.uk (until 9/12/02) New e-mail: e.asante@prion.ucl.ac.uk (active from now)
____________________________________
snip...see full text ;
BSE prions propagate as either variant CJD-like or sporadic CJD-like prion strains in transgenic mice expressing human prion protein
Emmanuel A. Asante, Jacqueline M. Linehan, Melanie Desbruslais, Susan Joiner, Ian Gowland, Andrew L. Wood, Julie Welch, Andrew F. Hill, Sarah E. Lloyd, Jonathan D.F. Wadsworth, and John Collinge1
Abstract
Variant Creutzfeldt–Jakob disease (vCJD) has been recognized to date only in individuals homozygous for methionine at PRNP codon 129. Here we show that transgenic mice expressing human PrP methionine 129, inoculated with either bovine spongiform encephalopathy (BSE) or variant CJD prions, may develop the neuropathological and molecular phenotype of vCJD, consistent with these diseases being caused by the same prion strain. Surprisingly, however, BSE transmission to these transgenic mice, in addition to producing a vCJD-like phenotype, can also result in a distinct molecular phenotype that is indistinguishable from that of sporadic CJD with PrPSc type 2. These data suggest that more than one BSE-derived prion strain might infect humans; it is therefore possible that some patients with a phenotype consistent with sporadic CJD may have a disease arising from BSE exposure.
Keywords: BSE/Creutzfeldt–Jakob disease/prion/transgenic
Discussion Prion propagation involves recruitment and conversion of host PrPC into PrPSc, and the degree of primary structural similarity between inoculated PrPSc and host PrPC is thought to be a key component of intermammalian transmission barriers (Prusiner et al., 1990). It is clear, however, that prion strain type can also be crucial, as clearly demonstrated by the very distinctive transmission properties of sporadic CJD 129MM and vCJD 129MM prions (of identical PrP primary structure) in either 129VV Tg152 (Hill et al., 1997; Collinge, 1999) or 129MM Tg35 mice. Prion strain type may also affect transmission barriers via an effect on PrPSc tertiary structure and state of aggregation (Hill et al., 1997; Collinge, 1999).
These 129MM Tg35 mice, in which human PrPSc types can be propagated, have been used to study the BSE-to-human species barrier. The frequent presence of sub-clinical prion disease in vCJD- and BSE-inoculated 129MM Tg35 mice further argues for the need to reassess current definitions of ‘species’ or transmission barriers that limit prion transmission between different hosts (Hill et al., 2000). Such barriers have hitherto been quantitated on the basis of either comparative end-point titrations in the two respective hosts, or by measuring the fall in incubation period between primary and subsequent passage as the prion strain adapts to the new host. Both methods rely on measurement of time to onset of a clinical syndrome. Modelling the BSE-to-human barrier in 129MM Tg35 mice would lead to the conclusion, on the basis of induced clinical disease, that a substantial barrier existed. How ever, it is clear that human PrPSc propagation can be efficiently induced by inoculation with BSE or vCJD prions, suggesting a smaller barrier to infection (but not to clinical disease) than hitherto thought (Collinge et al., 1995) in humans of the PRNP 129MM genotype. Humans infected with BSE prions, but who became asymptomatic carriers, may nevertheless pose a threat of iatrogenic transmission via medical and surgical procedures. Alternatively, it is possible that the lifespan of the laboratory mouse is insufficient to allow expression of clinical disease in most inoculated mice, whereas a higher proportion of infected humans might survive the incubation period to develop clinical signs of disease. Serial passage studies and titration of prions in these mice are in progress to study this further.
These studies further strengthen the evidence that vCJD is caused by a BSE-like prion strain. Also, remarkably, the key neuropathological hallmark of vCJD, the presence of abundant florid PrP plaques, can be recapitulated on BSE or vCJD transmission to these mice. However, the most surprising aspect of the studies was the finding that an alternate pattern of disease can be induced in 129MM Tg35 mice from primary transmission of BSE, with a molecular phenotype indistinguishable from that of a sub-type of sporadic CJD. This finding has important potential implications as it raises the possibility that some humans infected with BSE prions may develop a clinical disease indistinguishable from classical CJD associated with type 2 PrPSc. This is, in our experience, the commonest molecular sub-type of sporadic CJD. In this regard, it is of interest that the reported incidence of sporadic CJD has risen in the UK since the 1970s (Cousens et al., 1997). This has been attributed to improved case ascertainment, particularly as much of the rise is reported from elderly patients and similar rises in incidence were noted in other European countries without reported BSE (Will et al., 1998). However, it is now clear that BSE is present in many European countries, albeit at a much lower incidence than was seen in the UK. While improved ascertainment is likely to be a major factor in this rise, that some of these additional cases may be related to BSE exposure cannot be ruled out. It is of interest in this regard that a 2-fold increase in the reported incidence of sporadic CJD in 2001 has recently been reported for Switzerland, a country that had the highest incidence of cattle BSE in continental Europe between 1990 and 2002 (Glatzel et al., 2002). No epidemiological case–control studies with stratification of CJD cases by molecular sub-type have yet been reported. It will be important to review the incidence of sporadic CJD associated with PrPSc type 2 and other molecular sub-types in both BSE-affected and unaffected countries in the light of these findings. If human BSE prion infection can result in propagation of type 2 PrPSc, it would be expected that such cases would be indistinguishable on clinical, pathological and molecular criteria from classical CJD. It may also be expected that such prions would behave biologically like those isolated from humans with sporadic CJD with type 2 PrPSc. The transmission properties of prions associated with type 2 PrPSc from BSE-inoculated 129MM Tg35 mice are being investigated by serial passage.
We consider these data inconsistent with contamination of some of the 129MM Tg35 mice with sporadic CJD prions. These transmission studies were performed according to rigorous biosafety protocols for preparation of inocula and both the inoculation and care of mice, which are all uniquely identified by sub-cutaneous transponders. However, crucially, the same BSE inocula have been used on 129VV Tg152 and 129MM Tg45 mice, which are highly sensitive to sporadic CJD but in which such transmissions producing type 2 PrPSc were not observed. Furthermore, in an independent experiment, separate inbred lines of wild-type mice, which are highly resistant to sporadic CJD prions, also propagated two distinctive PrPSc types on challenge with either BSE or vCJD. No evidence of spontaneous prion disease or PrPSc has been seen in groups of uninoculated or mock-inoculated aged 129MM Tg35 mice.
While distinctive prion isolates have been derived from BSE passage in mice previously (designated 301C and 301V), these, in contrast to the data presented here, are propagated in mice expressing different prion proteins (Bruce et al., 1994). It is unclear whether our findings indicate the existence of more than one prion strain in individual cattle with BSE, with selection and preferential replication of distinct strains by different hosts, or that ‘mutation’ of a unitary BSE strain occurs in some types of host. Western blot analysis of single BSE isolates has not shown evidence of the presence of a proportion of monoglycosylated dominant PrPSc type in addition to the diglycosylated dominant pattern (data not shown). Extensive strain typing of large numbers of individual BSE-infected cattle either by biological or molecular methods has not been reported.
Presumably, the different genetic background of the different inbred mouse lines is crucial in determining which prion strain propagates on BSE inoculation. The transgenic mice described here have a mixed genetic background with contributions from FVB/N, C57BL/6 and 129Sv inbred lines; each mouse will therefore have a different genetic background. This may explain the differing response of individual 129MM Tg35 mice, and the difference between 129MM Tg35 and 129MM Tg45 mice, which are, like all transgenic lines, populations derived from single founders. Indeed, the consistent distinctive strain propagation in FVB and C57BL/6 versus SJL and RIIIS lines may allow mapping of genes relevant to strain selection and propagation, and these studies are in progress.
That different prion strains can be consistently isolated in different inbred mouse lines challenged with BSE prions argues that other species exposed to BSE may develop prion diseases that are not recognizable as being caused by the BSE strain by either biological or molecular strain typing methods. As with 129MM Tg35 mice, the prions replicating in such transmissions may be indistinguishable from naturally occurring prion strains. It remains of considerable concern whether BSE has transmitted to, and is being maintained in, European sheep flocks. Given the diversity of sheep breeds affected by scrapie, it has to be considered that some sheep might have become infected with BSE, but propagated a distinctive strain type indistinguishable from those of natural sheep scrapie.
atypical and typical BSE and Scrapie Zoonosis
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.
> However, to date, no CWD infections have been reported in people.
key word here is ‘reported’. science has shown that CWD in humans will look like sporadic CJD. SO, how can one assume that CWD has not already transmitted to humans? they can’t, and it’s as simple as that. from all recorded science to date, CWD has already transmitted to humans, and it’s being misdiagnosed as sporadic CJD. …terry
*** LOOKING FOR CWD IN HUMANS AS nvCJD or as an ATYPICAL CJD, LOOKING IN ALL THE WRONG PLACES $$$ ***
*** These results would seem to suggest that CWD does indeed have zoonotic potential, at least as judged by the compatibility of CWD prions and their human PrPC target. Furthermore, extrapolation from this simple in vitro assay suggests that if zoonotic CWD occurred, it would most likely effect those of the PRNP codon 129-MM genotype and that the PrPres type would be similar to that found in the most common subtype of sCJD (MM1).***
Chronic Wasting Disease CWD TSE Prion aka mad deer disease zoonosis
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.
ZOONOTIC CHRONIC WASTING DISEASE CWD TSE PRION UPDATE
Prion 2017 Conference
First evidence of intracranial and peroral transmission of Chronic Wasting Disease (CWD) into Cynomolgus macaques: a work in progress Stefanie Czub1, Walter Schulz-Schaeffer2, Christiane Stahl-Hennig3, Michael Beekes4, Hermann Schaetzl5 and Dirk Motzkus6 1
University of Calgary Faculty of Veterinary Medicine/Canadian Food Inspection Agency; 2Universitatsklinikum des Saarlandes und Medizinische Fakultat der Universitat des Saarlandes; 3 Deutsches Primaten Zentrum/Goettingen; 4 Robert-Koch-Institut Berlin; 5 University of Calgary Faculty of Veterinary Medicine; 6 presently: Boehringer Ingelheim Veterinary Research Center; previously: Deutsches Primaten Zentrum/Goettingen
This is a progress report of a project which started in 2009. 21 cynomolgus macaques were challenged with characterized CWD material from white-tailed deer (WTD) or elk by intracerebral (ic), oral, and skin exposure routes. Additional blood transfusion experiments are supposed to assess the CWD contamination risk of human blood product. Challenge materials originated from symptomatic cervids for ic, skin scarification and partially per oral routes (WTD brain). Challenge material for feeding of muscle derived from preclinical WTD and from preclinical macaques for blood transfusion experiments. We have confirmed that the CWD challenge material contained at least two different CWD agents (brain material) as well as CWD prions in muscle-associated nerves.
Here we present first data on a group of animals either challenged ic with steel wires or per orally and sacrificed with incubation times ranging from 4.5 to 6.9 years at postmortem. Three animals displayed signs of mild clinical disease, including anxiety, apathy, ataxia and/or tremor. In four animals wasting was observed, two of those had confirmed diabetes. All animals have variable signs of prion neuropathology in spinal cords and brains and by supersensitive IHC, reaction was detected in spinal cord segments of all animals. Protein misfolding cyclic amplification (PMCA), real-time quaking-induced conversion (RT-QuiC) and PET-blot assays to further substantiate these findings are on the way, as well as bioassays in bank voles and transgenic mice.
At present, a total of 10 animals are sacrificed and read-outs are ongoing. Preclinical incubation of the remaining macaques covers a range from 6.4 to 7.10 years. Based on the species barrier and an incubation time of > 5 years for BSE in macaques and about 10 years for scrapie in macaques, we expected an onset of clinical disease beyond 6 years post inoculation.
PRION 2017 DECIPHERING NEURODEGENERATIVE DISORDERS
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.
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. <***
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. <***
https://prion2018.org/
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
https://prion2018.org/wp-content/uploads/2018/05/program.pdf
https://prion2018.org/
THURSDAY, OCTOBER 04, 2018
Cervid to human prion transmission 5R01NS088604-04 Update
http://grantome.com/grant/NIH/R01-NS088604-04
http://chronic-wasting-disease.blogspot.com/2018/10/cervid-to-human-prion-transmission.html
snip...full text;
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. <***
https://prion2018.org/
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
https://prion2018.org/wp-content/uploads/2018/05/program.pdf
https://prion2018.org/
THURSDAY, OCTOBER 04, 2018
Cervid to human prion transmission 5R01NS088604-04 Update
http://grantome.com/grant/NIH/R01-NS088604-04
http://chronic-wasting-disease.blogspot.com/2018/10/cervid-to-human-prion-transmission.html
snip...full text;
SATURDAY, FEBRUARY 09, 2019
Experts: Yes, chronic wasting disease in deer is a public health issue — for people
FRIDAY, JULY 26, 2019
Chronic Wasting Disease in Cervids: Implications for Prion Transmission to Humans and Other Animal Species
10. ZOONOTIC, ZOONOSIS, CHRONIC WASTING DISEASE CWD TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHY TSE PRION AKA MAD DEER ELK DISEASE IN HUMANS, has it already happened, that should be the question...
''In particular the US data do not clearly exclude the possibility of human (sporadic or familial) TSE development due to consumption of venison. The Working Group thus recognizes a potential risk to consumers if a TSE would be present in European cervids.'' Scientific opinion on chronic wasting disease (II)
EFSA Panel on Biological Hazards (BIOHAZ) Antonia Ricci Ana Allende Declan Bolton Marianne Chemaly Robert Davies Pablo Salvador Fernández Escámez ... See all authors
First published: 17 January 2018 https://doi.org/10.2903/j.efsa.2018.5132 ;
also, see;
8. Even though human TSE‐exposure risk through consumption of game from European cervids can be assumed to be minor, if at all existing, no final conclusion can be drawn due to the overall lack of scientific data.
***> In particular the US data do not clearly exclude the possibility of human (sporadic or familial) TSE development due to consumption of venison.
The Working Group thus recognizes a potential risk to consumers if a TSE would be present in European cervids. It might be prudent considering appropriate measures to reduce such a risk, e.g. excluding tissues such as CNS and lymphoid tissues from the human food chain, which would greatly reduce any potential risk for consumers.. However, it is stressed that currently, no data regarding a risk of TSE infections from cervid products are available.
snip...
The tissue distribution of infectivity in CWD‐infected cervids is now known to extend beyond CNS and lymphoid tissues. While the removal of these specific tissues from the food chain would reduce human dietary exposure to infectivity, exclusion from the food chain of the whole carcass of any infected animal would be required to eliminate human dietary exposure.
85%+ of all human TSE prion, i.e. sporadic CJD, does NOT happen spontaneously, as some would wish you to think. never say never with the TSE Prion disease. ...terry
***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.***
Volume 2: Science
4. The link between BSE and vCJD
Summary 4.29 The evidence discussed above that vCJD is caused by BSE seems overwhelming. Uncertainties exist about the cause of CJD in farmers, their wives and in several abattoir workers. It seems that farmers at least might be at higher risk than others in the general population. 1 Increased ascertainment (ie, increased identification of cases as a result of greater awareness of the condition) seems unlikely, as other groups exposed to risk, such as butchers and veterinarians, do not appear to have been affected. The CJD in farmers seems to be similar to other sporadic CJD in age of onset, in respect to glycosylation patterns, and in strain-typing in experimental mice. Some farmers are heterozygous for the methionine/valine variant at codon 129, and their lymphoreticular system (LRS) does not contain the high levels of PrPSc found in vCJD.
***>It remains a remote possibility that when older people contract CJD from BSE the resulting phenotype is like sporadic CJD and is distinct from the vCJD phenotype in younger people...end
BSE INQUIRY
SATURDAY, JUNE 23, 2018
CDC
***> Diagnosis of Methionine/Valine Variant Creutzfeldt-Jakob Disease by Protein Misfolding Cyclic Amplification
Volume 24, Number 7—July 2018 Dispatch
THURSDAY, DECEMBER 12, 2019
Heidenhain Variant Creutzfeldt Jakob Disease hvCJD, sporadic spontaneous CJD and the TSE Prion December 14, 2019
22 years, rip mom dod 12/14/97 confirmed hvcjd, just made a promise to mom, and you don't break those promises, never forget, and never let them forget, before we all do...this pearl's for you! love terry
WEDNESDAY, DECEMBER 04, 2019
Three Cases of Creutzfeldt-Jakob Disease with Visual Disturbances as Initial Manifestation
WEDNESDAY, DECEMBER 25, 2019
Creutzfeldt-Jakob disease: a systematic review of global incidence, prevalence, infectivity, and incubation
We found that although CJD, particularly iatrogenic CJD, is rare, the incidence of sporadic CJD is increasing.
Saturday, November 23, 2019
Prion disease incidence in the United States, 2003–2015
Thank you for your submission. Below is a copy of your comment as we received it. Your comment will soon be with the editor for review. If accepted, your comment will be posted online at the earliest opportunity. Please note that your Publishing Agreement, included within your submission below, will be removed by editorial staff before we publish your letter.
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Article (citation):
. Prion disease incidence in the United States, 2003–2015. Neurology (2019); 10.1212/WNL.0000000000008680
https://n.neurology.org/content/early/2019/11/22/WNL.0000000000008680
The comment "RE: Prion disease incidence in the United States, 2003–2015" was submitted on 23 11 2019:
Greetings Neurology et al, I still find this hard to believe, especially with the new sporadic cjd called vpspr in humans, and the other new tse prion disease popping up in humans, along with the poor surveillance we have from state to state for human tse prion. with this continued belief of the UK BSE nvCJD only theory, meaning only those few tied to the typical C-BSE strain in cattle as nvCJD in humans, or what they call today vCJD, and that no other human tse on the globe is from any other animal tse prion like cwd tse prion in cervid, scrapie in sheep and goats, or the other atypical bse tse in cattle, and what about the outbreak of a new tse prion in a new livestock species, the camel. i think this belief, and continued statements of such (without reading the full study, i have no access as a peon), i believe helps continue to spread the tse prion around the globe, by ignoring the fact that all iatrogenic CJD is, is sporadic CJD, until the iatrogenic event is discovered, proven, documented, put in to the academic domain, and finally in the public domain. now we know that cwd in cervid and scrapie can transmit to pigs by oral route, and we also know out mad cow feed ban was a colossal failure. i also remember what some of these same scientist said long ago on this topic and cwd being zoonosis or not, and this was 2002, since then much science has come forth showing that cwd to humans not only is very probable, it most likely has already happened. we have doctors and scientist still claiming that 85%+ all human tse prion disease i.e. the sporadic cjd is a spontaneous event from nothing, just a funked out protein that twist wrongly, and that no other reason exist, and this is a dangerous precedent to set, without proof, and will continue to help spread the tse prion imo...
see;
Saturday, November 23, 2019 Prion disease incidence in the United States, 2003–2015
Terry S. Singeltary Sr. I am an Author of this Work, and the Work was prepared on my own time - not as part of my duties as an employee.
FRIDAY, OCTOBER 25, 2019
27th ANNUAL REPORT 2018 CREUTZFELDT-JAKOB DISEASE SURVEILLANCE
SUNDAY, MARCH 10, 2019
National Prion Disease Pathology Surveillance Center Cases Examined¹ Updated Feb 1, 2019 Variably protease-sensitive prionopathy VPSPr
MONDAY, AUGUST 26, 2019
Creutzfeldt Jakob Disease CJD, TSE, Prion, Surveillance Update August 2019
SATURDAY, AUGUST 24, 2019
Creutzfeldt-Jakob disease surveillance in Australia: update to 31 December 2018
SATURDAY, SEPTEMBER 21, 2019
National Variability in Prion Disease–Related Safety Policies for Neurologic Procedures
Friday, September 27, 2019
Prion disease and recommended procedures for flexible endoscope reprocessing – a review of policies worldwide and proposal for a simplified approach
FRIDAY, SEPTEMBER 06, 2019
Disinfection of Multi-Use Ocular Equipment for Ophthalmological Procedures: A Review of Clinical Effectiveness, Cost-Effectiveness, and Guidelines
THURSDAY, SEPTEMBER 26, 2019
Veterinary Biologics Guideline 3.32E: Guideline for minimising the risk of introducing transmissible spongiform encephalopathy prions and other infectious agents through veterinary biologics
Wednesday, September 11, 2019
Is the re-use of sterilized implant abutments safe enough? (Implant abutment safety) iatrogenic TSE Prion
New Variant Creutzfeldt Jakob Disease nvCJD or what is call now variant Creutzfeldt Jakob Disease or vCJD
WEDNESDAY, DECEMBER 04, 2019
Three Cases of Creutzfeldt-Jakob Disease with Visual Disturbances as Initial Manifestation
SATURDAY, DECEMBER 21, 2019
In vitro detection of haematogenous prions in white-tailed deer orally dosed with low concentrations of chronic wasting disease
THURSDAY, DECEMBER 19, 2019
The emergence of classical BSE from atypical/Nor98 scrapie
SUNDAY, AUGUST 09, 2009
CJD...Straight talk with...James Ironside...and...Terry Singeltary... 2009
TUESDAY, AUGUST 18, 2009
BSE-The Untold Story - joe gibbs and singeltary 1999 - 2009
TUESDAY, OCTOBER 29, 2019
America BSE 589.2001 FEED REGULATIONS, BSE SURVEILLANCE, BSE TESTING, and CJD TSE Prion
WEDNESDAY, AUGUST 15, 2018
***> The agent of H-type bovine spongiform encephalopathy associated with E211K prion protein polymorphism transmits after oronasal challenge
MONDAY, JANUARY 09, 2017
Oral Transmission of L-Type Bovine Spongiform Encephalopathy Agent among Cattle
CDC Volume 23, Number 2—February 2017
*** Consumption of L-BSE–contaminated feed may pose a risk for oral transmission of the disease agent to cattle.
*** Consumption of L-BSE–contaminated feed may pose a risk for oral transmission of the disease agent to cattle.
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.
PLOS ONE Journal
IBNC Tauopathy or TSE Prion disease, it appears, no one is sure
Terry S. Singeltary Sr., 03 Jul 2015 at 16:53 GMT
***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 ***
http://www.plosone.org/annotation/listThread.action?root=86610
***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 ***
http://www.plosone.org/annotation/listThread.action?root=86610
*** Singeltary reply ; Molecular, Biochemical and Genetic Characteristics of BSE in Canada Singeltary reply ;
P98 The agent of H-type bovine spongiform encephalopathy associated with E211K prion protein polymorphism transmits after oronasal challenge
Greenlee JJ (1), Moore SJ (1), and West Greenlee MH (2) (1) United States Department of Agriculture, Agricultural Research Service, National Animal Disease Center, Virus and Prion Research Unit, Ames, IA, United States (2) Department of Biomedical Sciences, Iowa State University College of Veterinary Medicine, Ames, IA, United States.
reading up on this study from Prion 2018 Conference, very important findings ;
***> This study demonstrates that the H-type BSE agent is transmissible by the oronasal route.
***> These results reinforce the need for ongoing surveillance for classical and atypical BSE to minimize the risk of potentially infectious tissues entering the animal or human food chains.
PRION 2018 CONFERENCE ABSTRACT
WEDNESDAY, OCTOBER 24, 2018
Experimental Infection of Cattle With a Novel Prion Derived From Atypical H-Type Bovine Spongiform Encephalopathy
Sunday, March 20, 2016
Docket No. FDA-2003-D-0432 (formerly 03D-0186) Use of Material from Deer and Elk in Animal Feed Singeltary Submission
Oral transmission and early lymphoid tropism of chronic wasting disease PrPres in mule deer fawns (Odocoileus hemionus)
Christina J. Sigurdson1, Elizabeth S. Williams2, Michael W. Miller3, Terry R. Spraker1,4, Katherine I. O'Rourke5 and Edward A. Hoover1
Department of Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523- 1671, USA1 Department of Veterinary Sciences, University of Wyoming, 1174 Snowy Range Road, University of Wyoming, Laramie, WY 82070, USA 2 Colorado Division of Wildlife, Wildlife Research Center, 317 West Prospect Road, Fort Collins, CO 80526-2097, USA3 Colorado State University Veterinary Diagnostic Laboratory, 300 West Drake Road, Fort Collins, CO 80523-1671, USA4 Animal Disease Research Unit, Agricultural Research Service, US Department of Agriculture, 337 Bustad Hall, Washington State University, Pullman, WA 99164-7030, USA5
Author for correspondence: Edward Hoover.Fax +1 970 491 0523. e-mail ehoover@lamar.colostate.edu
Mule deer fawns (Odocoileus hemionus) were inoculated orally with a brain homogenate prepared from mule deer with naturally occurring chronic wasting disease (CWD), a prion-induced transmissible spongiform encephalopathy. Fawns were necropsied and examined for PrP res, the abnormal prion protein isoform, at 10, 42, 53, 77, 78 and 80 days post-inoculation (p.i.) using an immunohistochemistry assay modified to enhance sensitivity. PrPres was detected in alimentary-tract-associated lymphoid tissues (one or more of the following: retropharyngeal lymph node, tonsil, Peyer's patch and ileocaecal lymph node) as early as 42 days p.i. and in all fawns examined thereafter (53 to 80 days p.i.). No PrPres staining was detected in lymphoid tissue of three control fawns receiving a control brain inoculum, nor was PrPres detectable in neural tissue of any fawn. PrPres-specific staining was markedly enhanced by sequential tissue treatment with formic acid, proteinase K and hydrated autoclaving prior to immunohistochemical staining with monoclonal antibody F89/160.1.5. These results indicate that CWD PrP res can be detected in lymphoid tissues draining the alimentary tract within a few weeks after oral exposure to infectious prions and may reflect the initial pathway of CWD infection in deer. The rapid infection of deer fawns following exposure by the most plausible natural route is consistent with the efficient horizontal transmission of CWD in nature and enables accelerated studies of transmission and pathogenesis in the native species.
snip...
These results indicate that mule deer fawns develop detectable PrP res after oral exposure to an inoculum containing CWD prions. In the earliest post-exposure period, CWD PrPres was traced to the lymphoid tissues draining the oral and intestinal mucosa (i.e. the retropharyngeal lymph nodes, tonsil, ileal Peyer's patches and ileocaecal lymph nodes), which probably received the highest initial exposure to the inoculum. Hadlow et al. (1982) demonstrated scrapie agent in the tonsil, retropharyngeal and mesenteric lymph nodes, ileum and spleen in a 10-month-old naturally infected lamb by mouse bioassay. Eight of nine sheep had infectivity in the retropharyngeal lymph node. He concluded that the tissue distribution suggested primary infection via the gastrointestinal tract. The tissue distribution of PrPres in the early stages of infection in the fawns is strikingly similar to that seen in naturally infected sheep with scrapie. These findings support oral exposure as a natural route of CWD infection in deer and support oral inoculation as a reasonable exposure route for experimental studies of CWD.
snip...
===================================
now, just what is in that deer feed? _ANIMAL PROTEIN_
Subject: MAD DEER/ELK DISEASE AND POTENTIAL SOURCES
Date: Sat, 25 May 2002 18:41:46 -0700
From: "Terry S. Singeltary Sr."
Reply-To: BSE-L
To: BSE-L
8420-20.5% Antler Developer For Deer and Game in the wild Guaranteed Analysis Ingredients / Products Feeding Directions
snip...
_animal protein_
BODE'S GAME FEED SUPPLEMENT #400 A RATION FOR DEER NET WEIGHT 50 POUNDS 22.6 KG.
snip...
_animal protein_
Ingredients
Grain Products, Plant Protein Products, Processed Grain By-Products, Forage Products, Roughage Products 15%, Molasses Products, __Animal Protein Products__, Monocalcium Phosphate, Dicalcium Pyosphate, Salt, Calcium Carbonate, Vitamin A Acetate with D-activated Animal Sterol (source of Vitamin D3), Vitamin E Supplement, Vitamin B12 Supplement, Riboflavin Supplement, Niacin Supplement, Calcium Panothenate, Choline Chloride, Folic Acid, Menadione Soduim Bisulfite Complex, Pyridoxine Hydorchloride, Thiamine Mononitrate, d-Biotin, Manganous Oxide, Zinc Oxide, Ferrous Carbonate, Calcium Iodate, Cobalt Carbonate, Dried Sacchoromyces Berevisiae Fermentation Solubles, Cellulose gum, Artificial Flavors added.
===================================
MORE ANIMAL PROTEIN PRODUCTS FOR DEER
Bode's #1 Game Pellets A RATION FOR DEER F3153
GUARANTEED ANALYSIS Crude Protein (Min) 16% Crude Fat (Min) 2.0% Crude Fiber (Max) 19% Calcium (Ca) (Min) 1.25% Calcium (Ca) (Max) 1.75% Phosphorus (P) (Min) 1.0% Salt (Min) .30% Salt (Max) .70%
Ingredients
Grain Products, Plant Protein Products, Processed Grain By-Products, Forage Products, Roughage Products, 15% Molasses Products, __Animal Protein Products__, Monocalcium Phosphate, Dicalcium Phosphate, Salt, Calcium Carbonate, Vitamin A Acetate with D-activated Animal Sterol (source of Vitamin D3) Vitamin E Supplement, Vitamin B12 Supplement, Roboflavin Supplement, Niacin Supplement, Calcium Pantothenate, Choline Chloride, Folic Acid, Menadione Sodium Bisulfite Complex, Pyridoxine Hydrochloride, Thiamine Mononitrate, e - Biotin, Manganous Oxide, Zinc Oxide, Ferrous Carbonate, Calcium Iodate, Cobalt Carbonate, Dried Saccharyomyces Cerevisiae Fermentation Solubles, Cellulose gum, Artificial Flavors added.
FEEDING DIRECTIONS Feed as Creep Feed with Normal Diet
INGREDIENTS
Grain Products, Roughage Products (not more than 35%), Processed Grain By-Products, Plant Protein Products, Forage Products, __Animal Protein Products__, L-Lysine, Calcium Carbonate, Salt, Monocalcium/Dicalcium Phosphate, Yeast Culture, Magnesium Oxide, Cobalt Carbonate, Basic Copper Chloride, Manganese Sulfate, Manganous Oxide, Sodium Selenite, Zinc Sulfate, Zinc Oxide, Sodium Selenite, Potassium Iodide, Ethylenediamine Dihydriodide, Vitamin E Supplement, Vitamin A Supplement, Vitamin D3 Supplement, Mineral Oil, Mold Inhibitor, Calcium Lignin Sulfonate, Vitamin B12 Supplement, Menadione Sodium Bisulfite Complex, Calcium Pantothenate, Riboflavin, Niacin, Biotin, Folic Acid, Pyridoxine Hydrochloride, Mineral Oil, Chromium Tripicolinate
DIRECTIONS FOR USE
Deer Builder Pellets is designed to be fed to deer under range conditions or deer that require higher levels of protein. Feed to deer during gestation, fawning, lactation, antler growth and pre-rut, all phases which require a higher level of nutrition. Provide adequate amounts of good quality roughage and fresh water at all times.
===================================================
DEPARTMENT OF HEALTH & HUMAN SERVICES PUBLIC HEALTH SERVICE FOOD AND DRUG ADMINISTRATION
April 9, 2001 WARNING LETTER
01-PHI-12 CERTIFIED MAIL RETURN RECEIPT REQUESTED
Brian J. Raymond, Owner Sandy Lake Mills 26 Mill Street P.O. Box 117 Sandy Lake, PA 16145 PHILADELPHIA DISTRICT
Tel: 215-597-4390
Dear Mr. Raymond:
Food and Drug Administration Investigator Gregory E. Beichner conducted an inspection of your animal feed manufacturing operation, located in Sandy Lake, Pennsylvania, on March 23, 2001, and determined that your firm manufactures animal feeds including feeds containing prohibited materials. The inspection found significant deviations from the requirements set forth in Title 21, code of Federal Regulations, part 589.2000 - Animal Proteins Prohibited in Ruminant Feed. The regulation is intended to prevent the establishment and amplification of Bovine Spongiform Encephalopathy (BSE) . Such deviations cause products being manufactured at this facility to be misbranded within the meaning of Section 403(f), of the Federal Food, Drug, and Cosmetic Act (the Act).
Our investigation found failure to label your swine feed with the required cautionary statement "Do Not Feed to cattle or other Ruminants" The FDA suggests that the statement be distinguished by different type-size or color or other means of highlighting the statement so that it is easily noticed by a purchaser.
In addition, we note that you are using approximately 140 pounds of cracked corn to flush your mixer used in the manufacture of animal feeds containing prohibited material. This flushed material is fed to wild game including deer, a ruminant animal. Feed material which may potentially contain prohibited material should not be fed to ruminant animals which may become part of the food chain.
The above is not intended to be an all-inclusive list of deviations from the regulations. As a manufacturer of materials intended for animal feed use, you are responsible for assuring that your overall operation and the products you manufacture and distribute are in compliance with the law. We have enclosed a copy of FDA's Small Entity Compliance Guide to assist you with complying with the regulation... blah, blah, blah...
==================================
Subject: MAD DEER/ELK DISEASE AND POTENTIAL SOURCES
Date: Sat, 25 May 2002 18:41:46 -0700
From: "Terry S. Singeltary Sr."
Reply-To: Bovine Spongiform Encephalopathy
now, what about those 'deer scents' of 100% urine', and the prion that is found in urine, why not just pass the prion with the urine to other deer...
Mrs. Doe Pee Doe in Estrus Model FDE1 Mrs. Doe Pee's Doe in Estrus is made from Estrus urine collected at the peak of the rut, blended with Fresh Doe Urine for an extremely effective buck enticer. Use pre-rut before the does come into heat. Use during full rut when bucks are most active. Use during post-rut when bucks are still actively looking for does. 1 oz.
ELK SCENT/SPRAY BOTTLE
Works anytime of the year *
100 % Cow Elk-in-Heat urine (2oz.) *
Economical - mix with water in spray mist bottle *
Use wind to your advantage
Product Code WP-ESB $9.95
prions in urine?
DEER & ELK URINE, LURES & SCENT CONTROL DEPARTMENT by MRS.DOE PEE'S Main Index
The Turkey Pro Sez... "Premium, fresh, top-quality, pure 100% undiluted deer lures from Mrs. Doe Pee really work. I won't trust anything else when I'm after big bucks. Sam Collora, owner of the company, proved how well his products work when he bagged this monster buck in 1996.............snip......end........CWD
-------- Original Message --------
Subject: ON THE ORIGIN OF MINK TME MARSH/HANSON (Scrapie in USA sheep, to TSE in USA cattle, or BOTH)
Date: Thu, 15 May 2003 15:23:46 -0500
From: "Terry S. Singeltary Sr." Reply-To: Bovine Spongiform Encephalopathy To: BSE-L@uni-karlsruhe.de
######## Bovine Spongiform Encephalopathy #########
***> These findings support oral exposure as a natural route of CWD infection in deer
***> cattle, pigs, sheep, cwd, tse, prion, oh my!
***> In contrast, cattle are highly susceptible to white-tailed deer CWD and mule deer CWD in experimental conditions but no natural CWD infections in cattle have been reported (Sigurdson, 2008; Hamir et al., 2006).
Sheep and cattle may be exposed to CWD via common grazing areas with affected deer but so far, appear to be poorly susceptible to mule deer CWD (Sigurdson, 2008). In contrast, cattle are highly susceptible to white-tailed deer CWD and mule deer CWD in experimental conditions but no natural CWD infections in cattle have been reported (Sigurdson, 2008; Hamir et al., 2006). It is not known how susceptible humans are to CWD but given that the prion can be present in muscle, it is likely that humans have been exposed to the agent via consumption of venison (Sigurdson, 2008). Initial experimental research suggests that human susceptibility to CWD is low and there may be a robust species barrier for CWD transmission to humans (Sigurdson, 2008), however the risk appetite for a public health threat may still find this level unacceptable.
cwd scrapie pigs oral routes
***> 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.
TUESDAY, APRIL 18, 2017
*** EXTREME USA FDA PART 589 TSE PRION FEED LOOP HOLE STILL EXIST, AND PRICE OF POKER GOES UP ***
8.CONSIDERING RECENT SCIENCE THAT CWD TSE PRION WILL TRANSMIT ORALLY TO PIGS AND ALSO SCRAPIE TO PIGS BY ORAL ROUTES, CONSIDERING CWD TRANSMIT EASILY TO CERVID BY ORAL ROUTE, CONSIDERING A NEW TSE PRION OUTBREAK IN A NEW LIVESTOCK SPECIES, THE CAMEL, CONSIDERING THE FACT THE USA THAT THE 1997 BSE feed regulation at 589.2000, which remains in effect but which applies only to feed for cattle and other ruminants, and specifically, the new section 589.2001, WAS AND STILL IS A TOTAL AND COLOSSAL FAILURE, AND PROVEN TO BE SO BY RECENT COMMENTS COMING FROM THE FDA, BUT FIRST, COMMENTS FROM DEFRA;
In the USA, under the Food and Drug Administration's BSE Feed Regulation (21 CFR 589.2000) most material (exceptions include milk, tallow, and gelatin) from deer and elk is prohibited for use in feed for ruminant animals. With regards to feed for non-ruminant animals, under FDA law, CWD positive deer may not be used for any animal feed or feed ingredients. For elk and deer considered at high risk for CWD, the FDA recommends that these animals do not enter the animal feed system. However, this recommendation is guidance and not a requirement by law.
Animals considered at high risk for CWD include:
1) animals from areas declared to be endemic for CWD and/or to be CWD eradication zones and
2) deer and elk that at some time during the 60-month period prior to slaughter were in a captive herd that contained a CWD-positive animal.
Therefore, in the USA, materials from cervids other than CWD positive animals may be used in animal feed and feed ingredients for non-ruminants.
The amount of animal PAP that is of deer and/or elk origin imported from the USA to GB can not be determined, however, as it is not specified in TRACES. It may constitute a small percentage of the 8412 kilos of non-fish origin processed animal proteins that were imported from US into GB in 2011.
Overall, therefore, it is considered there is a __greater than negligible risk___ that (nonruminant) animal feed and pet food containing deer and/or elk protein is imported into GB.
There is uncertainty associated with this estimate given the lack of data on the amount of deer and/or elk protein possibly being imported in these products.
snip.....
FDA Reports on VFD Compliance
John Maday
August 30, 2019 09:46 AM VFD-Form 007 (640x427)
Before and after the current Veterinary Feed Directive rules took full effect in January, 2017, the FDA focused primarily on education and outreach. ( John Maday ) Before and after the current Veterinary Feed Directive (VFD) rules took full effect in January, 2017, the FDA focused primarily on education and outreach to help feed mills, veterinarians and producers understand and comply with the requirements. Since then, FDA has gradually increased the number of VFD inspections and initiated enforcement actions when necessary. On August 29, FDA released its first report on inspection and compliance activities. The report, titled “Summary Assessment of Veterinary Feed Directive Compliance Activities Conducted in Fiscal Years 2016 – 2018,” is available online.
SUNDAY, SEPTEMBER 1, 2019
***> FDA Reports on VFD Compliance
CDC
New Outbreak of TSE Prion in NEW LIVESTOCK SPECIES
Mad Camel Disease
Volume 24, Number 6—June 2018 Research
Prion Disease in Dromedary Camels, Algeria Abstract
Prions cause fatal and transmissible neurodegenerative diseases, including Creutzfeldt-Jakob disease in humans, scrapie in small ruminants, and bovine spongiform encephalopathy (BSE). After the BSE epidemic, and the associated human infections, began in 1996 in the United Kingdom, general concerns have been raised about animal prions. We detected a prion disease in dromedary camels (Camelus dromedarius) in Algeria. Symptoms suggesting prion disease occurred in 3.1% of dromedaries brought for slaughter to the Ouargla abattoir in 2015–2016. We confirmed diagnosis by detecting pathognomonic neurodegeneration and disease-specific prion protein (PrPSc) in brain tissues from 3 symptomatic animals. Prion detection in lymphoid tissues is suggestive of the infectious nature of the disease. PrPSc biochemical characterization showed differences with BSE and scrapie. Our identification of this prion disease in a geographically widespread livestock species requires urgent enforcement of surveillance and assessment of the potential risks to human and animal health.
SNIP...
The possibility that dromedaries acquired the disease from eating prion-contaminated waste needs to be considered.
Tracing the origin of prion diseases is challenging. In the case of CPD, the traditional extensive and nomadic herding practices of dromedaries represent a formidable factor for accelerating the spread of the disease at long distances, making the path of its diffusion difficult to determine. Finally, the major import flows of live animals to Algeria from Niger, Mali, and Mauritania (27) should be investigated to trace the possible origin of CPD from other countries. Camels are a vital animal species for millions of persons globally. The world camel population has a yearly growth rate of 2.1% (28). In 2014, the population was estimated at ≈28 million animals, but this number is probably underestimated.. Approximately 88% of camels are found in Africa, especially eastern Africa, and 12% are found in Asia. Official data reported 350,000 dromedaries in Algeria in 2014 (28).
On the basis of phenotypic traits and sociogeographic criteria, several dromedary populations have been suggested to exist in Algeria (29). However, recent genetic studies in Algeria and Egypt point to a weak differentiation of the dromedary population as a consequence of historical use as a cross-continental beast of burden along trans-Saharan caravan routes, coupled with traditional extensive/nomadic herding practices (30).
Such genetic homogeneity also might be reflected in PRNP. Studies on PRNP variability in camels are therefore warranted to explore the existence of genotypes resistant to CPD, which could represent an important tool for CPD management as it was for breeding programs for scrapie eradication in sheep. In the past 10 years, the camel farming system has changed rapidly, with increasing setup of periurban dairy farms and dairy plants and diversification of camel products and market penetration (13). This evolution requires improved health standards for infectious diseases and, in light of CPD, for prion diseases.
The emergence of another prion disease in an animal species of crucial importance for millions of persons worldwide makes it necessary to assess the risk for humans and develop evidence-based policies to control and limit the spread of the disease in animals and minimize human exposure. The implementation of a surveillance system for prion diseases would be a first step to enable disease control and minimize human and animal exposure. Finally, the diagnostic capacity of prion diseases needs to be improved in all countries in Africa where dromedaries are part of the domestic livestock. https://wwwnc.cdc.gov/eid/article/24/6/17-2007_article ;
***> IMPORTS AND EXPORTS <***
***SEE MASSIVE AMOUNTS OF BANNED ANIMAL PROTEIN AKA MAD COW FEED IN COMMERCE USA DECADES AFTER POST BAN ***
MONDAY, FEBRUARY 25, 2019
***> MAD DOGS AND ENGLISHMEN BSE, SCRAPIE, CWD, CJD, TSE PRION A REVIEW 2019
Terry S. Singeltary Sr.
posted by Terry S. Singeltary Sr. | 3:41 PM
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