Tracking and clarifying differential traits of classical- and atypical L-type bovine spongiform encephalopathy prions after transmission from cattle to cynomolgus monkeys
Tracking and clarifying differential traits of classical- and atypical L-type bovine spongiform encephalopathy prions after transmission from cattle to cynomolgus monkeys
Ken’ichi Hagiwara , Yuko Sato, Yoshio Yamakawa, Hideyuki Hara, Minoru Tobiume, Yuko Okemoto-Nakamura, Tetsutaro Sata, Motohiro Horiuchi, Hiroaki Shibata, Fumiko Ono
Published: May 16, 2019https://doi.org/10.1371/journal.pone.0216807
Abstract
Classical- (C-) and atypical L-type bovine spongiform encephalopathy (BSE) prions cause different pathological phenotypes in cattle brains, and the disease-associated forms of each prion protein (PrPSc) has a dissimilar biochemical signature. Bovine C-BSE prions are the causative agent of variant Creutzfeldt-Jakob disease. To date, human infection with L-BSE prions has not been reported, but they can be transmitted experimentally from cows to cynomolgus monkeys (Macaca fascicularis), a non-human primate model. When transmitted to monkeys, C- and L-BSE prions induce different pathological phenotypes in the brain. However, when isolated from infected brains, the two prion proteins (PrPSc) have similar biochemical signatures (i.e., electrophoretic mobility, glycoforms, and resistance to proteinase K). Such similarities suggest the possibility that L-BSE prions alter their virulence to that of C-BSE prions during propagation in monkeys. To clarify this possibility, we conducted bioassays using inbred mice. C-BSE prions with or without propagation in monkeys were pathogenic to mice, and exhibited comparable incubation periods in secondary passage in mice. By contrast, L-BSE prions, either with or without propagation in monkeys, did not cause the disease in mice, indicating that the pathogenicity of L-BSE prions does not converge towards a C-BSE prion type in this primate model. These results suggest that, although C- and L-BSE prions propagated in cynomolgus monkeys exhibit similar biochemical PrPSc signatures and consist of the monkey amino acid sequence, the two prions maintain strain-specific conformations of PrPSc in which they encipher and retain unique pathogenic traits.
snip...
Discussion Interspecies prion transmission entails adaptation of the original prions to a new host animal. During this process, prion strain traits can be retained or unpredictably modified. Studies to date have reported that experimental transmission of C-, L-, and H-BSE prions from cows to other animals has prompted emergence of different strain types. Examples have been found in transmission of C-BSE prions to inbred mice (SJL) [45], to transgenic mice expressing human PrPC [46], to transgenic mice expressing mouse-hamster chimeric PrPC [47], and to sheep [48]. Likewise, transmission of H-BSE prions to inbred mice or transgenic mice expressing bovine PrPC caused emergence of the C-BSE prion phenotype(s) [49–51]. L-BSE prion transmission to inbred mice (discussed below) [24] or to transgenic mice expressing sheep PrPC [19] generated prions that were biochemically and pathogenetically similar to C-BSE prions. In addition, transmission of L-BSE prions to sheep induced the emergence of prions that possessed altered pathogenicity [25] or induced an unknown phenotype [26].
The zoonotic potential of L-BSE prions is suggested by transmissibility from cows to cynomolgus monkeys (Macaca fascicularis) [16, 17] and lemurs (Microcebus murinus) [18]. The brains of cynomolgus monkeys infected with C- or L-BSE prions exhibited different pathological phenotypes [13, 16, 17, 23], whereas each type of PrPSc that accumulated in the brain had similar biochemical traits (Fig 1). Considering the plasticity of L-BSE prions during interspecies transmission in previous studies, the potential for L-BSE prions in a non-human primate model to lead to emergence of a C-BSE strain type was of concern because such a phenomenon challenges our current understanding of the etiology of vCJD. However, we found no evidence in the present study to support this. Recently, an in vitro real-time quaking-induced conversion (RT-QuIC) assay was applied to brain samples from cynomolgus monkeys infected with C- and L-BSE prions from cows [52]. In the reported data of this RT-QuIC assay, signals unique to C-BSE prions were not observed in brain samples from monkeys infected with L-BSE prions. These data suggest that infection of cynomolgus monkeys with L-BSE prions did not induce C-BSE prions in the brain above the detection limit of the RT-QuIC assay. Our bioassay results support this. From these results, we suspect the possibility of L-BSE prions transforming into C-BSE prions in humans is low, although the parallelism of monkeys and humans should be carefully considered.
In terms of genetic polymorphism, the codon corresponding to PrPC amino acid position 129 encodes methionine or valine in human Prnp. The cynomolgus monkeys in the present study had Prnp with the 129Met/Met genotype, corresponding with the human 129Met/Met genotype (see Materials and methods). The polymorphism at codon 129 is known to affect the phenotypes of sporadic CJD patients [1] and to determine human susceptibility to C-BSE prions causing vCJD (reviewed in [53]). As no case of human infection by L-BSE prions has been reported, the effects of the polymorphism at codon 129 on human susceptibility to L-BSE prions are currently unclear. To address this question, brain tissues from transgenic mice with human Prnp homozygous for methionine (129Met/Met) or homozygous for valine (129Val/Val) were assessed by in vitro protein misfolding cyclic amplification (PMCA) analysis. PMCA analysis revealed that PrPC with 129Met/Met and 129Val/Val genotypes could both be converted to PrPSc in vitro using bovine L-BSE prions as seeds [54].
In a prior study, L-BSE prions that accumulated in the bovine brain were compared with a panel of sporadic CJD prions by transmission to transgenic mice expressing human PrPC (tg650 mice). L-BSE prions elicited a 100% attack rate in tg650 mice, but no evidence was found to support a link between bovine L-BSE prions and known types of sporadic CJD prions [55]. In another study, L-BSE prions that had been transmitted from cows to cynomolgus monkeys were inoculated into transgenic mice expressing bovine PrPC (tg100 mice). They reported that monkey L-BSE prions induced disease in tg100 mice with a 100% attack rate, suggesting that propagation of L-BSE prions in cynomolgus monkeys does not attenuate its virulence in cattle [56]. The present study demonstrates the preserved virulence of bovine and monkey L-BSE prions, by making use of inbred mice that were permissive for C- but not for L-BSE prions. The results of the present study and those of the studies on the tg650 and the tg100 mice are complementary, and are important for understanding the nature of the L-BSE prion agent.
Lastly, we confirmed that bovine L-BSE prions were not transmissible to three lines of inbred mice by intracranial administration (Table 1). In another study, L-BSE prions were reported to develop into a prion agent with similar signatures as bovine C-BSE prions after two serial passages from cows to C57BL/6 or SJL mice [24]. The reasons for these inconsistent results are unknown, but one possibility is different routes of inoculation into mice, as noted previously [25]; intracranial inoculation was employed in our study, whereas a combination of intracerebral and intraperitoneal inoculations was used for the first passage in the previous report [24]. On this subject, routes of inoculation have been reported to influence phenotypic features in experimental transmission of C-BSE prions from cows to IM mice (Prnpb mice), although strain properties were retained overall [57]. Based on the assumption that prions contain a mixture of components, including a major component, and a quasispecies consisting of a variety of minor components with subtly different conformations [9], it is of interest to investigate whether different routes of inoculation favor propagation of different components within the quasispecies, and if such a selection bias accounts for the distinct phenotypic features in these experiments.
The present study suggests that, although C- and L-BSE prions that propagated in cynomolgus monkeys exhibit similar biochemical PrPSc signatures, composed of the monkey amino acid sequence, the two prions do not merge but retain unique pathogenic traits, possibly by holding strain-specific conformations of PrPSc. We are currently carrying out a mouse bioassay of ‘monkey-to-monkey’-passaged L-BSE prions (i.e., passaged twice in cynomolgus monkeys). L-BSE prions after two passages in the monkeys induced no neurological signs in the mice by 580 days after the inoculation. This study is ongoing and will be reported separately.
TUESDAY, APRIL 30, 2019
Pathobiology, Genetics, and Detection of Transmissible Spongiform Encephalopathies 2018 Annual Report
WEDNESDAY, APRIL 24, 2019
USDA Announces Atypical Bovine Spongiform Encephalopathy Detection Aug 29, 2018 A Review of Science 2019
SUNDAY, APRIL 14, 2019
Estimation of prion infectivity in tissues of cattle infected with atypical BSE by real time-quaking induced conversion assay
WEDNESDAY, APRIL 17, 2019
Estimating the impact on food and edible materials of changing scrapie control measures: The scrapie control model
TUESDAY, MARCH 26, 2019
USDA ARS 2018 USAHA RESOLUTIONS TWO PRONGED APPROACH NEEDED FOR ADVANCING CATTLE TRACEABILITY
THURSDAY, MARCH 14, 2019
USDA APHIS CDC FDA BSE TSE PRION UPDATE 2019
MONDAY, FEBRUARY 25, 2019
MAD DOGS AND ENGLISHMEN BSE, SCRAPIE, CWD, CJD, TSE PRION A REVIEW 2019
THURSDAY, FEBRUARY 28, 2019
BSE infectivity survives burial for five years with only limited spread
SATURDAY, MARCH 2, 2019
MAD COW TSE PRION DISEASE AND THE PEER REVIEW PROCESS OF BSe Science $$$
PRION 2018 CONFERENCE
P98 The agent of H-type bovine spongiform encephalopathy associated with E211K prion protein polymorphism transmits after oronasal challenge
Greenlee JJ (1), Moore SJ (1), and West Greenlee MH (2) (1) United States Department of Agriculture, Agricultural Research Service, National Animal Disease Center, Virus and Prion Research Unit, Ames, IA, United States (2) Department of Biomedical Sciences, Iowa State University College of Veterinary Medicine, Ames, IA, United States.
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
TUESDAY, AUGUST 28, 2018
USDA finds BSE infection in Florida cow 08/28/18 6:43 PM
http://animalhealthreportpriontse..blogspot.com/2018/08/usda-finds-bse-infection-in-florida-cow.html
WEDNESDAY, AUGUST 29, 2018
USDA Announces Atypical Bovine Spongiform Encephalopathy Detection USDA 08/29/2018 10:00 AM EDT
WEDNESDAY, AUGUST 29, 2018
Transmissible Spongiform Encephalopathy TSE Prion Atypical BSE Confirmed Florida Update USA August 28, 2018
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.
THURSDAY, JULY 20, 2017
USDA OIE Alabama Atypical L-type BASE Bovine Spongiform Encephalopathy BSE animal feeds for ruminants rule, 21 CFR 589.200
WEDNESDAY, MARCH 15, 2017
In vitro amplification of H-type atypical bovine spongiform encephalopathy by protein misfolding cyclic amplification
"When considering the atypical L-BSE and H-BSE diseases of cattle, they have been assessed in both non-human primate and transgenic mouse bioassays (with mice transgenic for human PRNP) and both model systems indicate that H-BSE and L-BSE may have increased zoonotic potential compare with C-BSE.
***The detection of all types of BSE is therefore of significant importance."
http://bse-atypical.blogspot.com/2017/03/in-vitro-amplification-of-h-type.html
Saturday, June 25, 2011
Transmissibility of BSE-L and Cattle-Adapted TME Prion Strain to Cynomolgus Macaque
"BSE-L in North America may have existed for decades"
***> P.108: Successful oral challenge of adult cattle with classical BSE
Sandor Dudas1,*, Kristina Santiago-Mateo1, Tammy Pickles1, Catherine Graham2, and Stefanie Czub1 1Canadian Food Inspection Agency; NCAD Lethbridge; Lethbridge, Alberta, Canada; 2Nova Scotia Department of Agriculture; Pathology Laboratory; Truro, Nova Scotia, Canada
Classical Bovine spongiform encephalopathy (C-type BSE) is a feed- and food-borne fatal neurological disease which can be orally transmitted to cattle and humans. Due to the presence of contaminated milk replacer, it is generally assumed that cattle become infected early in life as calves and then succumb to disease as adults. Here we challenged three 14 months old cattle per-orally with 100 grams of C-type BSE brain to investigate age-related susceptibility or resistance. During incubation, the animals were sampled monthly for blood and feces and subjected to standardized testing to identify changes related to neurological disease. At 53 months post exposure, progressive signs of central nervous system disease were observed in these 3 animals, and they were euthanized. Two of the C-BSE animals tested strongly positive using standard BSE rapid tests, however in 1 C-type challenged animal, Prion 2015 Poster Abstracts S67 PrPsc was not detected using rapid tests for BSE. Subsequent testing resulted in the detection of pathologic lesion in unusual brain location and PrPsc detection by PMCA only.
***Our study demonstrates susceptibility of adult cattle to oral transmission of classical BSE.
We are further examining explanations for the unusual disease presentation in the third challenged animal.
***our findings suggest that possible transmission risk of H-type BSE to sheep and human. Bioassay will be required to determine whether the PMCA products are infectious to these animals.
P.86: Estimating the risk of transmission of BSE and scrapie to ruminants and humans by protein misfolding cyclic amplification
Morikazu Imamura, Naoko Tabeta, Yoshifumi Iwamaru, and Yuichi Murayama
National Institute of Animal Health; Tsukuba, Japan
To assess the risk of the transmission of ruminant prions to ruminants and humans at the molecular level, we investigated the ability of abnormal prion protein (PrPSc) of typical and atypical BSEs (L-type and H-type) and typical scrapie to convert normal prion protein (PrPC) from bovine, ovine, and human to proteinase K-resistant PrPSc-like form (PrPres) using serial protein misfolding cyclic amplification (PMCA).
Six rounds of serial PMCA was performed using 10% brain homogenates from transgenic mice expressing bovine, ovine or human PrPC in combination with PrPSc seed from typical and atypical BSE- or typical scrapie-infected brain homogenates from native host species. In the conventional PMCA, the conversion of PrPC to PrPres was observed only when the species of PrPC source and PrPSc seed matched. However, in the PMCA with supplements (digitonin, synthetic polyA and heparin), both bovine and ovine PrPC were converted by PrPSc from all tested prion strains. On the other hand, human PrPC was converted by PrPSc from typical and H-type BSE in this PMCA condition.
Although these results were not compatible with the previous reports describing the lack of transmissibility of H-type BSE to ovine and human transgenic mice, our findings suggest that possible transmission risk of H-type BSE to sheep and human. Bioassay will be required to determine whether the PMCA products are infectious to these animals.
P.170: Potential detection of oral transmission of H type atypical BSE in cattle using in vitro conversion
***P.170: Potential detection of oral transmission of H type atypical BSE in cattle using in vitro conversion
Sandor Dudas, John G Gray, Renee Clark, and Stefanie Czub Canadian Food Inspection Agency; Lethbridge, AB Canada
Keywords: Atypical BSE, oral transmission, RT-QuIC
The detection of bovine spongiform encephalopathy (BSE) has had a significant negative impact on the cattle industry worldwide. In response, governments took actions to prevent transmission and additional threats to animal health and food safety. While these measures seem to be effective for controlling classical BSE, the more recently discovered atypical BSE has presented a new challenge. To generate data for risk assessment and control measures, we have challenged cattle orally with atypical BSE to determine transmissibility and mis-folded prion (PrPSc) tissue distribution. Upon presentation of clinical symptoms, animals were euthanized and tested for characteristic histopathological changes as well as PrPSc deposition.
The H-type challenged animal displayed vacuolation exclusively in rostral brain areas but the L-type challenged animal showed no evidence thereof. To our surprise, neither of the animals euthanized, which were displaying clinical signs indicative of BSE, showed conclusive mis-folded prion accumulation in the brain or gut using standard molecular or immunohistochemical assays. To confirm presence or absence of prion infectivity, we employed an optimized real-time quaking induced conversion (RT-QuIC) assay developed at the Rocky Mountain Laboratory, Hamilton, USA.
Detection of PrPSc was unsuccessful for brain samples tests from the orally inoculated L type animal using the RT-QuIC. It is possible that these negative results were related to the tissue sampling locations or that type specific optimization is needed to detect PrPSc in this animal. We were however able to consistently detect the presence of mis-folded prions in the brain of the H-type inoculated animal. Considering the negative and inconclusive results with other PrPSc detection methods, positive results using the optimized RT-QuIC suggests the method is extremely sensitive for H-type BSE detection. This may be evidence of the first successful oral transmission of H type atypical BSE in cattle and additional investigation of samples from these animals are ongoing.
Detection of PrPBSE and prion infectivity in the ileal Peyer’s patch of young calves as early as 2 months after oral challenge with classical bovine spongiform encephalopathy
Ivett Ackermann1 , Anne Balkema‑Buschmann1 , Reiner Ulrich2 , Kerstin Tauscher2 , James C. Shawulu1 , Markus Keller1 , Olanrewaju I. Fatola1 , Paul Brown3 and Martin H. Groschup1*
Abstract
In classical bovine spongiform encephalopathy (C-BSE), an orally acquired prion disease of cattle, the ileal Peyer’s patch (IPP) represents the main entry port for the BSE agent. In earlier C-BSE pathogenesis studies, cattle at 4–6 months of age were orally challenged, while there are strong indications that the risk of infection is highest in young animals. In the present study, unweaned calves aged 4–6 weeks were orally challenged to determine the earli‑ est time point at which newly formed PrPBSE and BSE infectivity are detectable in the IPP. For this purpose, calves were culled 1 week as well as 2, 4, 6 and 8 months post-infection (mpi) and IPPs were examined for BSE infectivity using a bovine PrP transgenic mouse bioassay, and for PrPBSE by immunohistochemistry (IHC) and protein misfolding cyclic amplifcation (PMCA) assays. For the frst time, BSE prions were detected in the IPP as early as 2 mpi by transgenic mouse bioassay and PMCA and 4 mpi by IHC in the follicular dendritic cells (FDCs) of the IPP follicles. These data indi‑ cate that BSE prions propagate in the IPP of unweaned calves within 2 months of oral uptake of the agent.
In summary, our study demonstrates for the frst time PrPBSE (by PMCA) and prion infectivity (by mouse bioassay) in the ileal Peyer’s patch (IPP) of young calves as early as 2 months after infection. From 4 mpi nearly all calves showed PrPBSE positive IPP follicles (by IHC), even with PrPBSE accumulation detectable in FDCs in some animals. Finally, our results confrm the IPP as the early port of entry for the BSE agent and a site of initial propagation of PrPBSE and infectivity during the early pathogenesis of the disease. Terefore, our study supports the recommendation to remove the last four metres of the small intestine (distal ileum) at slaughter, as designated by current legal requirements for countries with a controlled BSE risk status, as an essential measure for consumer and public health protection.
A study comparing preclinical cattle infected naturally with BSE to clinically affected cattle either naturally or experimentally infected with BSE by the oral route found the most abundant PrPSc in the brainstem area (39), which is consistent with ascension to the brain from the gut by sympathetic and parasympathetic projections (40). In our experiment, abundant prions were observed in the brainstem of cattle with clinical signs of BSE, which is similar to the amount in their thalamus or midbrain regions. Interestingly, prions in the brainstem of cattle with clinical evidence of BSE seeded the RT-QuIC reactions faster than any other brain region despite the brainstem area having lower EIA OD values (Table 2) in comparison to other brain regions. This suggests that higher concentrations of prions do not necessarily seed the reaction faster. Perhaps prions of the brainstem exist in a preferred conformation for better conversion despite being present in lower concentrations.
snip...
The 2004 enhanced BSE surveillance program was so flawed, that one of the top TSE prion Scientist for the CDC, Dr. Paul Brown stated ; Brown, who is preparing a scientific paper based on the latest two mad cow cases to estimate the maximum number of infected cows that occurred in the United States, said he has "absolutely no confidence in USDA tests before one year ago" because of the agency's reluctance to retest the Texas cow that initially tested positive.
see ;
CDC - Bovine Spongiform Encephalopathy and Variant Creutzfeldt ... Dr. Paul Brown is Senior Research Scientist in the Laboratory of Central Nervous System ... Address for correspondence: Paul Brown, Building 36, Room 4A-05, ...
PAUL BROWN COMMENT TO ME ON THIS ISSUE
Tuesday, September 12, 2006 11:10 AM
"Actually, Terry, I have been critical of the USDA handling of the mad cow issue for some years, and with Linda Detwiler and others sent lengthy detailed critiques and recommendations to both the USDA and the Canadian Food Agency."
OR, what the Honorable Phyllis Fong of the OIG found ;
Finding 2 Inherent Challenges in Identifying and Testing High-Risk Cattle Still Remain
IT is of my opinion, that the OIE and the USDA et al, are the soul reason, and responsible parties, for Transmissible Spongiform Encephalopathy TSE prion diseases, including typical and atypical BSE, typical and atypical Scrapie, and all strains of CWD, and human TSE there from, spreading around the globe. I have lost all confidence of this organization as a regulatory authority on animal disease, and consider it nothing more than a National Trading Brokerage for all strains of animal TSE, just to satisfy there commodity. AS i said before, OIE should hang up there jock strap now, since it appears they will buckle every time a country makes some political hay about trade protocol, commodities and futures. IF they are not going to be science based, they should do everyone a favor and dissolve there organization. JUST because of low documented human body count with nvCJD and the long incubation periods, the lack of sound science being replaced by political and corporate science in relations with the fact that science has now linked some sporadic CJD with atypical BSE and atypical scrapie, and the very real threat of CWD being zoonosis, I believed the O.I.E. has failed terribly and again, I call for this organization to be dissolved...
Monday, May 05, 2014
Member Country details for listing OIE CWD 2013 against the criteria of Article 1.2.2., the Code Commission recommends consideration for listing
Friday, December 5, 2014
SPECIAL ALERT The OIE recommends strengthening animal disease surveillance worldwide
IN A NUT SHELL ; (Adopted by the International Committee of the OIE on 23 May 2006) 11. Information published by the OIE is derived from appropriate declarations made by the official Veterinary Services of Member Countries. The OIE is not responsible for inaccurate publication of country disease status based on inaccurate information or changes in epidemiological status or other significant events that were not promptly reported to the Central Bureau,
MONDAY, JANUARY 21, 2019
Bovine Spongiform Encephalopathy BSE TSE Prion Surveillance FDA USDA APHIS FSIS UPDATE 2019
Prion Conference 2018
O5 Prion Disease in Dromedary Camels
Babelhadj B (1), Di Bari MA (2), Pirisinu L (2), Chiappini B (2), Gaouar SB (3), Riccardi G (2), Marcon S (2), Agrimi U (2), Nonno R (2), Vaccari G (2) (1) École Normale Supérieure Ouargla. Laboratoire de protection des écosystèmes en zones arides et semi arides University Kasdi Merbah Ouargla, Ouargla, Algeria; (2) Istituto Superiore di Sanità, Department of Food Safety, Nutrition and Veterinary Public Health, Rome, Italy (3) University Abou Bekr Bélkaid, Tlemcen, Algeria.
Prions are responsible for fatal and transmissible neurodegenerative diseases including CreutzfeldtJakob disease in humans, scrapie in small ruminants and bovine spongiform encephalopathy (BSE). Following the BSE epidemic and the demonstration of its zoonotic potential, general concerns have been raised on animal prions.
Here we report the identification of a prion disease in dromedary camels (Camelus dromedarius) in Algeria and designate it as Camel Prion Disease (CPD). In the last years, neurological symptoms have been observed in adult male and female dromedaries presented for slaughter at the Ouargla abattoir. The symptoms include weight loss, behavioral abnormalities and neurological symptoms such as tremors, aggressiveness, hyper-reactivity, typical down and upwards movements of the head, hesitant and uncertain gait, ataxia of the hind limbs, occasional falls and difficult getting up. During 2015 and 2016, symptoms suggestive of prion disease were observed in 3.1% of 2259 dromedaries presented at ante-mortem examination. Laboratory diagnosis was obtained in three symptomatic dromedaries, sampled in 2016 and 2017, by the detection of typical neurodegeneration and disease-specific prion protein (PrPSc) in brain tissues.
Histopathological examination revealed spongiform change, gliosis and neuronal loss preferentially in grey matter of subcortical brain areas. Abundant PrPSc deposition was detected in the same brain areas by immunohistochemistry and PET-blot. Western blot analysis confirmed the presence of PK-resistant PrPSc, whose N-terminal cleaved PK-resistant core was characterized by a mono-glycosylated dominant form and by a distinctive N-terminal cleavage, different from that observed in BSE and scrapie.
PrPSc was also detected, by immunohistochemistry, in all sampled lymph nodes (cervical, prescapular and lumbar aortic) of the only animal from which they were collected.
The PRNP sequence of the two animals for which frozen material was available, showed 100% nucleotide identity with the PRNP sequence already reported for dromedary camel.
Overall, these data demonstrate the presence of a prion disease in dromedary camelswhose nature, origin and spread need further investigations. However, our preliminary observations on the rather high prevalence of symptomatic dromedaries and the involvement of lymphoid tissues, are consistent with CPD being an infectious disease. In conclusion, the emergence of a new prion disease in a livestock species of crucial importance for millions of people around the world, makes urgent to assess the risk for humans and to develop policies able to control the spread of the disease in animals and to minimize human exposure.
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.
***> IMPORTS AND EXPORTS <***
***SEE MASSIVE AMOUNTS OF BANNED ANIMAL PROTEIN AKA MAD COW FEED IN COMMERCE USA DECADES AFTER POST BAN ***
USA MAD COW CASE 2018 FLORIDA
WEDNESDAY, SEPTEMBER 26, 2018
JAVMA In Short Update USDA announces detection of atypical BSE
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.
THURSDAY, OCTOBER 04, 2018
Cervid to human prion transmission 5R01NS088604-04 Update
Saturday, December 15, 2018
***> ADRD Summit RFI Singeltary COMMENT SUBMISSION BSE, SCRAPIE, CWD, AND HUMAN TSE PRION DISEASE December 14, 2018
SATURDAY, JANUARY 5, 2019
Low levels of classical BSE infectivity in rendered fat tissue
***> FRIDAY, DECEMBER 14, 2018 MAD COW USA FLASHBACK Texas Style
FRIDAY DECEMBER 14, 2018
THURSDAY, JANUARY 3, 2019
MAD COW USDA DISEASE BSE TSE Prion
THURSDAY, OCTOBER 22, 2015
Former Ag Secretary Ann Veneman talks women in agriculture and we talk mad cow disease USDA and what really happened
HOW TO COVER UP MAD COW DISEASE IN TEXAS
WEDNESDAY, AUGUST 29, 2018
OIE Bovine spongiform encephalopathy, United States of America Information received on 29/08/2018 from Dr John Clifford, Official Delegate, Chief Trade Advisor, APHIS USDA
''The event is resolved. No more reports will be submitted.''
well, so much for those herd mates exposed to this atypical BSE cow, and all those trace in and trace outs.
The OIE, USDA, and the BSE MRR policy is a joke, a sad, very sad joke...
Saturday, July 23, 2016
BOVINE SPONGIFORM ENCEPHALOPATHY BSE TSE PRION SURVEILLANCE, TESTING, AND SRM REMOVAL UNITED STATE OF AMERICA UPDATE JULY 2016
Tuesday, July 26, 2016
Atypical Bovine Spongiform Encephalopathy BSE TSE Prion UPDATE JULY 2016
Monday, June 20, 2016
Specified Risk Materials SRMs BSE TSE Prion Program
Wednesday, January 23, 2019
CFIA SFCR Guidance on Specified risk material (SRM) came into force on January 15, 2019
MONDAY, JANUARY 21, 2019
Bovine Spongiform Encephalopathy BSE TSE Prion Surveillance FDA USDA APHIS FSIS UPDATE 2019
SUNDAY, MARCH 10, 2019
National Prion Disease Pathology Surveillance Center Cases Examined¹ Updated Feb 1, 2019 Variably protease-sensitive prionopathy VPSPr
Terry S. Singeltary Sr.
posted by Terry S. Singeltary Sr. at
11:41 AM
0 Comments:
Post a Comment
Subscribe to Post Comments [Atom]
<< Home