Brazil investigating two possible cases of mad cow disease in humans
Brazil investigating two possible cases of mad cow disease in humans
CONTRIBUTOR
Rodrigo Viga Reuters
PUBLISHED
NOV 11, 2021 12:11PM EST
Adds details of cases, context on China ban
RIO DE JANEIRO, Nov 11 (Reuters) - Brazilian authorities are investigating two possible cases of mad cow disease in humans in Rio de Janeiro state, a municipal health secretary said in a statement on Thursday, raising a red flag for meatpackers that already halted beef exports to China.
On Sept. 4 Brazil confirmed two cases of what it called "atypical" mad cow disease in animals, triggering a suspension of beef exports to China under a standing bilateral agreement.
At the time, Brazil's Agriculture Ministry stressed that the two cases identified in meat plants in the states of Mato Grosso and Minas Gerais had generated spontaneously and were not related to contaminated feed, as in classic mad cow disease.
On Thursday, municipal health authorities in the city of Rio said federal biomedical institute Fiocruz had flagged two cases of "prion disease," which can occur spontaneously in elderly patients or by eating contaminated beef in younger populations.
The municipal health authorities said the two cases identified in residents of the Rio suburbs had been referred to state health authorities, without giving the patients' ages.
The new cases could further delay a Chinese decision on lifting the Brazilian beef ban, which has stranded dozens of shipments, rerouted many others and weighed on beef exports from Latin America's largest country.
Brazil's Agriculture Ministry, along with major Brazilian beef exporters JBS SA JBSS3.SA, Minerva SA BEEF3.SA and Marfrig Global Foods SA MRFG3.SA did not immediately respond to requests for comment.
(Reporting by Rodrigo Viga Writing by Ana Mano Editing by Brad Haynes, Kirsten Donovan)
((ana.mano@thomsonreuters.com; Tel: +55-11-5644-7704; Mob: +55-119-4470-4529; Reuters Messaging: ana.mano.thomsonreuters.com@reuters.net))
https://www.nasdaq.com/articles/brazil-investigating-two-possible-cases-of-mad-cow-disease-in-humans
November 11, 2021
1:47 PM CST
Last Updated 3 hours ago
Brazil ag ministry says cases of Creutzfeldt-Jakob disease unrelated to beef consumption
Reuters
SAO PAULO, Nov 11 (Reuters) - Brazil's agriculture ministry said an ongoing investigation of suspected cases of Creutzfeldt-Jakob disease are not related to the consumption of beef or beef byproducts, according to a statement on Thursday.
The ministry explained that the suspected cases are of the sporadic form of the illness, which is not related to Bovine Spongiform Encephalitis (BSE), or mad cow disease.
Reporting by Nayara Figueiredo Writing by Ana Mano; editing by Stephen Eisenhammer
UPDATE 3-Brazil plays down 'mad cow' risk in suspect Rio cases By Nayara Figueiredo, Rodrigo Viga Gaier
3 MIN READ
(Adds Fiocruz statement)
SAO PAULO/RIO DE JANEIRO, Nov 11 (Reuters) - Brazil’s Agriculture Ministry said that two cases reported on Thursday of a neurodegenerative disorder in patients in Rio de Janeiro state were not related to beef consumption, tamping down fears of possible “mad cow” disease causing human illness.
Federal biomedical institute Fiocruz, which is investigating the possibility of Bovine Spongiform Encephalitis - the official name for mad cow disease - said the two patients are suspected of having the “sporadic” form of Creutzfeldt-Jakob disease not related to beef consumption.
On Sept. 4, Brazil confirmed two cases of what it called "atypical" mad cow disease in animals, triggering a suspension here of beef exports to China under a standing bilateral agreement.
At the time, the Agriculture Ministry stressed that the two cases identified in meat plants in the states of Mato Grosso and Minas Gerais had generated spontaneously and were not related to contaminated feed, as in classic mad cow disease.
On Thursday, the ministry said the two cases of suspected Creutzfeldt-Jakob disease in humans had “no relation with consumption of beef or subproducts contaminated with Bovine Spongiform Encephalitis, known as ‘Mad Cow’ disease.”
sporadic/spontaneous CJD can be caused by atypical and typical BSE and Scrapie...it's just science!
''In the first experimental study, H-type and L-type BSE were inoculated into transgenic mice expressing all three genotypes of the human PRNP at codon 129 and into adapted into ARQ and VRQ transgenic sheep mice. The results showed the alterations of the capacities to cross the human barrier species (mouse model) and emergence of sporadic CJD agents in Hu PrP expressing mice: type 2 sCJD in homozygous TgVal129 VRQ-passaged L-BSE, and type 1 sCJD in homozygous TgVal 129 and TgMet129 VRQ-passaged H-BSE.''
2.3.2. New evidence on the zoonotic potential of atypical BSE and atypical scrapie prion strains
PLEASE NOTE;
2.3.2. New evidence on the zoonotic potential of atypical BSE and atypical scrapie prion strainsNo
Olivier Andreoletti, INRA Research Director, Institut National de la Recherche Agronomique (INRA) – École Nationale Vétérinaire de Toulouse (ENVT), invited speaker, presented the results of two recently published scientific articles of interest, of which he is co-author: ‘Radical Change in Zoonotic Abilities of Atypical BSE Prion Strains as Evidenced by Crossing of Sheep Species Barrier in Transgenic Mice’ (MarinMoreno et al., 2020) and ‘The emergence of classical BSE from atypical/Nor98 scrapie’ (Huor et al., 2019).
In the first experimental study, H-type and L-type BSE were inoculated into transgenic mice expressing all three genotypes of the human PRNP at codon 129 and into adapted into ARQ and VRQ transgenic sheep mice. The results showed the alterations of the capacities to cross the human barrier species (mouse model) and emergence of sporadic CJD agents in Hu PrP expressing mice: type 2 sCJD in homozygous TgVal129 VRQ-passaged L-BSE, and type 1 sCJD in homozygous TgVal 129 and TgMet129 VRQ-passaged H-BSE.
''In the first experimental study, H-type and L-type BSE were inoculated into transgenic mice expressing all three genotypes of the human PRNP at codon 129 and into adapted into ARQ and VRQ transgenic sheep mice. The results showed the alterations of the capacities to cross the human barrier species (mouse model) and emergence of sporadic CJD agents in Hu PrP expressing mice: type 2 sCJD in homozygous TgVal129 VRQ-passaged L-BSE, and type 1 sCJD in homozygous TgVal 129 and TgMet129 VRQ-passaged H-BSE.''
***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.***
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.
https://www.nature.com/articles/srep11573
O.05: Transmission of prions to primates after extended silent incubation periods: Implications for BSE and scrapie risk assessment in human populations
Emmanuel Comoy, Jacqueline Mikol, Valerie Durand, Sophie Luccantoni, Evelyne Correia, Nathalie Lescoutra, Capucine Dehen, and Jean-Philippe Deslys Atomic Energy Commission; Fontenay-aux-Roses, France
Prion diseases (PD) are the unique neurodegenerative proteinopathies reputed to be transmissible under field conditions since decades. The transmission of Bovine Spongiform Encephalopathy (BSE) to humans evidenced that an animal PD might be zoonotic under appropriate conditions. Contrarily, in the absence of obvious (epidemiological or experimental) elements supporting a transmission or genetic predispositions, PD, like the other proteinopathies, are reputed to occur spontaneously (atpical animal prion strains, sporadic CJD summing 80% of human prion cases).
Non-human primate models provided the first evidences supporting the transmissibiity of human prion strains and the zoonotic potential of BSE. Among them, cynomolgus macaques brought major information for BSE risk assessment for human health (Chen, 2014), according to their phylogenetic proximity to humans and extended lifetime. We used this model to assess the zoonotic potential of other animal PD from bovine, ovine and cervid origins even after very long silent incubation periods.
*** We recently observed the direct transmission of a natural classical scrapie isolate to macaque after a 10-year silent incubation period,
***with features similar to some reported for human cases of sporadic CJD, albeit requiring fourfold long incubation than BSE. Scrapie, as recently evoked in humanized mice (Cassard, 2014),
***is the third potentially zoonotic PD (with BSE and L-type BSE),
***thus questioning the origin of human sporadic cases.
We will present an updated panorama of our different transmission studies and discuss the implications of such extended incubation periods on risk assessment of animal PD for human health.
===============
***thus questioning the origin of human sporadic cases***
===============
***our findings suggest that possible transmission risk of H-type BSE to sheep and human. Bioassay will be required to determine whether the PMCA products are infectious to these animals.
==============
https://prion2015.files.wordpress.com/2015/05/prion2015abstracts.pdf
***Transmission data also revealed that several scrapie prions propagate in HuPrP-Tg mice with efficiency comparable to that of cattle BSE. While the efficiency of transmission at primary passage was low, subsequent passages resulted in a highly virulent prion disease in both Met129 and Val129 mice.
***Transmission of the different scrapie isolates in these mice leads to the emergence of prion strain phenotypes that showed similar characteristics to those displayed by MM1 or VV2 sCJD prion.
***These results demonstrate that scrapie prions have a zoonotic potential and raise new questions about the possible link between animal and human prions.
http://www.tandfonline.com/doi/abs/10.1080/19336896.2016.1163048?journalCode=kprn20
Prion diseases (PD) are the unique neurodegenerative proteinopathies reputed to be transmissible under field conditions since decades. The transmission of Bovine Spongiform Encephalopathy (BSE) to humans evidenced that an animal PD might be zoonotic under appropriate conditions. Contrarily, in the absence of obvious (epidemiological or experimental) elements supporting a transmission or genetic predispositions, PD, like the other proteinopathies, are reputed to occur spontaneously (atpical animal prion strains, sporadic CJD summing 80% of human prion cases).
Non-human primate models provided the first evidences supporting the transmissibiity of human prion strains and the zoonotic potential of BSE. Among them, cynomolgus macaques brought major information for BSE risk assessment for human health (Chen, 2014), according to their phylogenetic proximity to humans and extended lifetime. We used this model to assess the zoonotic potential of other animal PD from bovine, ovine and cervid origins even after very long silent incubation periods.
*** We recently observed the direct transmission of a natural classical scrapie isolate to macaque after a 10-year silent incubation period,
***with features similar to some reported for human cases of sporadic CJD, albeit requiring fourfold long incubation than BSE. Scrapie, as recently evoked in humanized mice (Cassard, 2014),
***is the third potentially zoonotic PD (with BSE and L-type BSE),
***thus questioning the origin of human sporadic cases.
We will present an updated panorama of our different transmission studies and discuss the implications of such extended incubation periods on risk assessment of animal PD for human health.
===============
***thus questioning the origin of human sporadic cases***
===============
***our findings suggest that possible transmission risk of H-type BSE to sheep and human. Bioassay will be required to determine whether the PMCA products are infectious to these animals.
==============
https://prion2015.files.wordpress.com/2015/05/prion2015abstracts.pdf
***Transmission data also revealed that several scrapie prions propagate in HuPrP-Tg mice with efficiency comparable to that of cattle BSE. While the efficiency of transmission at primary passage was low, subsequent passages resulted in a highly virulent prion disease in both Met129 and Val129 mice.
***Transmission of the different scrapie isolates in these mice leads to the emergence of prion strain phenotypes that showed similar characteristics to those displayed by MM1 or VV2 sCJD prion.
***These results demonstrate that scrapie prions have a zoonotic potential and raise new questions about the possible link between animal and human prions.
http://www.tandfonline.com/doi/abs/10.1080/19336896.2016.1163048?journalCode=kprn20
PRION 2016 TOKYO
Saturday, April 23, 2016
SCRAPIE WS-01: Prion diseases in animals and zoonotic potential 2016
Prion. 10:S15-S21. 2016 ISSN: 1933-6896 printl 1933-690X online
Taylor & Francis
Prion 2016 Animal Prion Disease Workshop Abstracts
WS-01: Prion diseases in animals and zoonotic potential
Transmission of the different scrapie isolates in these mice leads to the emergence of prion strain phenotypes that showed similar characteristics to those displayed by MM1 or VV2 sCJD prion.
These results demonstrate that scrapie prions have a zoonotic potential and raise new questions about the possible link between animal and human prions.
http://www.tandfonline.com/doi/abs/10.1080/19336896.2016.1163048?journalCode=kprn20
Title: Transmission of scrapie prions to primate after an extended silent incubation period)
*** In complement to the recent demonstration that humanized mice are susceptible to scrapie, we report here the first observation of direct transmission of a natural classical scrapie isolate to a macaque after a 10-year incubation period. Neuropathologic examination revealed all of the features of a prion disease: spongiform change, neuronal loss, and accumulation of PrPres throughout the CNS.
*** This observation strengthens the questioning of the harmlessness of scrapie to humans, at a time when protective measures for human and animal health are being dismantled and reduced as c-BSE is considered controlled and being eradicated.
*** Our results underscore the importance of precautionary and protective measures and the necessity for long-term experimental transmission studies to assess the zoonotic potential of other animal prion strains.
http://www.ars.usda.gov/research/publications/publications.htm?SEQ_NO_115=313160
1: J Infect Dis 1980 Aug;142(2):205-8
Oral transmission of kuru, Creutzfeldt-Jakob disease, and scrapie to nonhuman primates.
Gibbs CJ Jr, Amyx HL, Bacote A, Masters CL, Gajdusek DC.
Kuru and Creutzfeldt-Jakob disease of humans and scrapie disease of sheep and goats were transmitted to squirrel monkeys (Saimiri sciureus) that were exposed to the infectious agents only by their nonforced consumption of known infectious tissues. The asymptomatic incubation period in the one monkey exposed to the virus of kuru was 36 months; that in the two monkeys exposed to the virus of Creutzfeldt-Jakob disease was 23 and 27 months, respectively; and that in the two monkeys exposed to the virus of scrapie was 25 and 32 months, respectively. Careful physical examination of the buccal cavities of all of the monkeys failed to reveal signs or oral lesions. One additional monkey similarly exposed to kuru has remained asymptomatic during the 39 months that it has been under observation.
snip...
The successful transmission of kuru, Creutzfeldt-Jakob disease, and scrapie by natural feeding to squirrel monkeys that we have reported provides further grounds for concern that scrapie-infected meat may occasionally give rise in humans to Creutzfeldt-Jakob disease.
PMID: 6997404
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=6997404&dopt=Abstract
Recently the question has again been brought up as to whether scrapie is transmissible to man. This has followed reports that the disease has been transmitted to primates. One particularly lurid speculation (Gajdusek 1977) conjectures that the agents of scrapie, kuru, Creutzfeldt-Jakob disease and transmissible encephalopathy of mink are varieties of a single "virus". The U.S. Department of Agriculture concluded that it could "no longer justify or permit scrapie-blood line and scrapie-exposed sheep and goats to be processed for human or animal food at slaughter or rendering plants" (ARC 84/77)" The problem is emphasised by the finding that some strains of scrapie produce lesions identical to the once which characterise the human dementias"
Whether true or not. the hypothesis that these agents might be transmissible to man raises two considerations. First, the safety of laboratory personnel requires prompt attention. Second, action such as the "scorched meat" policy of USDA makes the solution of the acrapie problem urgent if the sheep industry is not to suffer grievously.
snip...
76/10.12/4.6
Nature. 1972 Mar 10;236(5341):73-4.
Transmission of scrapie to the cynomolgus monkey (Macaca fascicularis).
Gibbs CJ Jr, Gajdusek DC.
Nature 236, 73 - 74 (10 March 1972); doi:10.1038/236073a0
Transmission of Scrapie to the Cynomolgus Monkey (Macaca fascicularis)
C. J. GIBBS jun. & D. C. GAJDUSEK
National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, Maryland
SCRAPIE has been transmitted to the cynomolgus, or crab-eating, monkey (Macaca fascicularis) with an incubation period of more than 5 yr from the time of intracerebral inoculation of scrapie-infected mouse brain. The animal developed a chronic central nervous system degeneration, with ataxia, tremor and myoclonus with associated severe scrapie-like pathology of intensive astroglial hypertrophy and proliferation, neuronal vacuolation and status spongiosus of grey matter. The strain of scrapie virus used was the eighth passage in Swiss mice (NIH) of a Compton strain of scrapie obtained as ninth intracerebral passage of the agent in goat brain, from Dr R. L. Chandler (ARC, Compton, Berkshire).
Wednesday, February 16, 2011
IN CONFIDENCE
SCRAPIE TRANSMISSION TO CHIMPANZEES
IN CONFIDENCE
Many times media portrays atypical BSE strains as a spontaneous or sporadic event caused by old age. Sciences has shown us otherwise. All atypical BSE cases are not sporadic/spontaneous, OIE has recognized this. Atypical BSE is a risk factor for feed, science has shown us this, we must now recognize this risk factor in the FDA 589.2001 BSE feed regulatory system, we must also bring awareness...terry
OIE Conclusions on transmissibility of atypical BSE among cattle
Given that cattle have been successfully infected by the oral route, at least for L-BSE, it is reasonable to conclude that atypical BSE is potentially capable of being recycled in a cattle population if cattle are exposed to contaminated feed. In addition, based on reports of atypical BSE from several countries that have not had C-BSE, it appears likely that atypical BSE would arise as a spontaneous disease in any country, albeit at a very low incidence in old cattle. In the presence of livestock industry practices that would allow it to be recycled in the cattle feed chain, it is likely that some level of exposure and transmission may occur. As a result, since atypical BSE can be reasonably considered to pose a potential background level of risk for any country with cattle, the recycling of both classical and atypical strains in the cattle and broader ruminant populations should be avoided.
Annex 7 (contd) AHG on BSE risk assessment and surveillance/March 2019
34 Scientific Commission/September 2019
3. Atypical BSE
The Group discussed and endorsed with minor revisions an overview of relevant literature on the risk of atypical BSE being recycled in a cattle population and its zoonotic potential that had been prepared ahead of the meeting by one expert from the Group. This overview is provided as Appendix IV and its main conclusions are outlined below. With regard to the risk of recycling of atypical BSE, recently published research confirmed that the L-type BSE prion (a type of atypical BSE prion) may be orally transmitted to calves1 . In light of this evidence, and the likelihood that atypical BSE could arise as a spontaneous disease in any country, albeit at a very low incidence, the Group was of the opinion that it would be reasonable to conclude that atypical BSE is potentially capable of being recycled in a cattle population if cattle were to be exposed to contaminated feed. Therefore, the recycling of atypical strains in cattle and broader ruminant populations should be avoided.
The Group acknowledged the challenges in demonstrating the zoonotic transmission of atypical strains of BSE in natural exposure scenarios. Overall, the Group was of the opinion that, at this stage, it would be premature to reach a conclusion other than that atypical BSE poses a potential zoonotic risk that may be different between atypical strains.
4. Definitions of meat-and-bone meal (MBM) and greaves
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REFERENCES
SNIP...END SEE FULL TEXT;
TUESDAY, SEPTEMBER 07, 2021
Atypical Bovine Spongiform Encephalopathy BSE OIE, FDA 589.2001 FEED REGULATIONS, and Ingestion Therefrom
***> Consumption of L-BSE–contaminated feed may pose a risk for oral transmission of the disease agent to cattle.
***> As a result, since atypical BSE can be reasonably considered to pose a potential background level of risk for any country with cattle, the recycling of both classical and atypical strains in the cattle and broader ruminant populations should be avoided.
***> 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.
Emerg Infect Dis. 2017 Feb; 23(2): 284–287. doi: 10.3201/eid2302.161416 PMCID: PMC5324790 PMID: 28098532 Oral Transmission of L-Type Bovine Spongiform Encephalopathy Agent among Cattle Hiroyuki Okada,corresponding author Yoshifumi Iwamaru, Morikazu Imamura, Kohtaro Miyazawa, Yuichi Matsuura, Kentaro Masujin, Yuichi Murayama, and Takashi Yokoyama Author information Copyright and License information Disclaimer This article has been cited by other articles in PMC. Go to: Abstract To determine oral transmissibility of the L-type bovine spongiform encephalopathy (BSE) prion, we orally inoculated 16 calves with brain homogenates of the agent. Only 1 animal, given a high dose, showed signs and died at 88 months. These results suggest low risk for oral transmission of the L-BSE agent among cattle.
Keywords: atypical bovine spongiform encephalopathy, cattle, L-type, prion, oral transmission, L-BSE, prions and related diseases, zoonoses The epidemic of bovine spongiform encephalopathy (BSE) in cattle is thought to be caused by oral infection through consumption of feed containing the BSE agent (prion). Since 2003, different neuropathologic and molecular phenotypes of BSE have been identified as causing ≈110 cases of atypical BSE worldwide, mainly in aged cattle. Although the etiology and pathogenesis of atypical BSE are not yet fully understood, atypical BSE prions possibly cause sporadic cases of BSE (1).
The L-type BSE (L-BSE) prion has been experimentally transmitted to cattle by intracerebral challenge, and the incubation period was is shorter than that for classical BSE (C-BSE) prions (2–6). The origin of transmissible mink encephalopathy in ranch-raised mink is thought to be caused by ingestion of L-BSE–infected material (7). Although L-BSE has been orally transmitted to mouse lemurs (8), it remains to be established whether L-BSE can be transmitted to cattle by oral infection. We therefore investigated the transmissibility of L-BSE by the oral route and tissue distribution of disease-associated prion protein (PrPSc) in cattle. All experiments involving animals were performed with the approval of the Animal Ethical Committee and the Animal Care and Use Committee of the National Institute of Animal Health (approval nos. 07–88 and 08–010).
snip...
The neuroanatomical PrPSc distribution pattern of orally challenged cattle differed somewhat from that described in cattle naturally and intracerebrally challenged with L-BSE (2–6,11,13,14), The conspicuous differences between the case we report and cases of natural and experimental infection are 1) higher amounts of PrPSc in the caudal medulla oblongata and the spinal cord coupled with that in the thalamus and the more rostral brainstem and 2) relatively low amounts of PrPSc in the cerebral cortices and the olfactory bulb. Furthermore, fewer PrPSc deposits in the dorsal motor nucleus of the vagus nerve may indicate that the parasympathetic retrogressive neuroinvasion pathway does not contribute to transport of the L-BSE prion from the gut to the brain, which is in contrast to the vagus-associated transport of the agent in C-BSE (15). PrPSc accumulation in the extracerebral tissues may be a result of centrifugal trafficking of the L-BSE prion from the central nervous system along somatic or autonomic nerve fibers rather than centripetal propagation of the agent (4,6,9). Consumption of L-BSE–contaminated feed may pose a risk for oral transmission of the disease agent to cattle.
Our study clearly confirms, experimentally, the potential risk for interspecies oral transmission of the agent of L-BSE. In our model, this risk appears higher than that for the agent of classical BSE, which could only be transmitted to mouse lemurs after a first passage in macaques (14). We report oral transmission of the L-BSE agent in young and adult primates. Transmission by the IC route has also been reported in young macaques (6,7). A previous study of L-BSE in transgenic mice expressing human PrP suggested an absence of any transmission barrier between cattle and humans for this particular strain of the agent of BSE, in contrast to findings for the agent of classical BSE (9). Thus, it is imperative to maintain measures that prevent the entry of tissues from cattle possibly infected with the agent of L-BSE into the food chain.
Research Project: Pathobiology, Genetics, and Detection of Transmissible Spongiform Encephalopathies Location: Virus and Prion Research
Title: The agent of H-type bovine spongiform encephalopathy associated with E211K prion protein polymorphism transmits after oronasal challenge
Author item Greenlee, Justin item MOORE, S - Orise Fellow item WEST-GREENLEE, M - Iowa State University
Submitted to: Prion
Publication Type: Abstract Only
Publication Acceptance Date: 5/14/2018
Publication Date: 5/22/2018
Citation: Greenlee, J.J., Moore, S.J., West Greenlee, M.H. 2018. The agent of H-type bovine spongiform encephalopathy associated with E211K prion protein polymorphism transmits after oronasal challenge. Prion 2018, May 22-25, 2018, Santiago de Compostela, Spain. Paper No. P98, page 116. Interpretive Summary:
Technical Abstract: In 2006, a case of H-type bovine spongiform encephalopathy (BSE) was reported in a cow with a previously unreported prion protein polymorphism (E211K). The E211K polymorphism is heritable and homologous to the E200K mutation in humans that is the most frequent PRNP mutation associated with familial Creutzfeldt-Jakob disease. Although the prevalence of the E211K polymorphism is low, cattle carrying the K211 allele develop H-type BSE with a rapid onset after experimental inoculation by the intracranial route.
The purpose of this study was to investigate whether the agents of H-type BSE or H-type BSE associated with the E211K polymorphism transmit to wild type cattle or cattle with the K211 allele after oronasal exposure.
Wild type (EE211) or heterozygous (EK211) cattle were oronasally inoculated with either H-type BSE from the 2004 US H-type BSE case (n=3) or from the 2006 US H-type case associated with the E211K polymorphism (n=4) using 10% w/v brain homogenates.
Cattle were observed daily throughout the course of the experiment for the development of clinical signs.
At approximately 50 months post-inoculation, one steer (EK211 inoculated with E211K associated H-BSE) developed clinical signs including inattentiveness, loss of body condition, weakness, ataxia, and muscle fasciculations and was euthanized.
Enzyme immunoassay confirmed that abundant misfolded protein was present in the brainstem, and immunohistochemistry demonstrated PrPSc throughout the brain.
Western blot analysis of brain tissue from the clinically affected steer was consistent with the E211K H-type BSE inoculum.
With the experiment currently at 55 months post-inoculation, no other cattle in this study have developed clinical signs suggestive of prion disease.
This study demonstrates that the H-type BSE agent is transmissible by the oronasal route.
These results reinforce the need for ongoing surveillance for classical and atypical BSE to minimize the risk of potentially infectious tissues entering the animal or human food chains.
P98 The agent of H-type bovine spongiform encephalopathy associated with E211K prion protein polymorphism transmits after oronasal challenge
Greenlee JJ (1), Moore SJ (1), and West Greenlee MH (2) (1) United States Department of Agriculture, Agricultural Research Service, National Animal Disease Center, Virus and Prion Research Unit, Ames, IA, United States (2) Department of Biomedical Sciences, Iowa State University College of Veterinary Medicine, Ames, IA, United States.
In 2006, a case of H-type bovine spongiform encephalopathy (BSE) was reported in a cow with a previously unreported prion protein polymorphism (E211K).
The E211K polymorphism is heritable and homologous to the E200K mutation in humans that is the most frequent PRNP mutation associated with familial Creutzfeldt-Jakob disease.
Although the prevalence of the E211K polymorphism is low, cattle carrying the K211 allele develop H-type BSE with a rapid onset after experimental inoculation by the intracranial route.
The purpose of this study was to investigate whether the agents of H-type BSE or H-type BSE associated with the E211K polymorphism transmit to wild type cattle or cattle with the K211 allele after oronasal exposure.
Wild type (EE211) or heterozygous (EK211) cattle were oronasally inoculated with either H-type BSE from the 2004 US Htype BSE case (n=3) or from the 2006 US H-type case associated with the E211K polymorphism (n=4) using 10% w/v brain homogenates.
Cattle were observed daily throughout the course of the experiment for the development of clinical signs.
At approximately 50 months post-inoculation, one steer (EK211 inoculated with E211K associated H-BSE) developed clinical signs including inattentiveness, loss of body condition, weakness, ataxia, and muscle fasciculations and was euthanized.
Enzyme immunoassay confirmed that abundant misfolded protein was present in the brainstem, and immunohistochemistry demonstrated PrPSc throughout the brain.
Western blot analysis of brain tissue from the clinically affected steer was consistent with the E211K H-type BSE inoculum.
With the experiment currently at 55 months post-inoculation, no other cattle in this study have developed clinical signs suggestive of prion disease. This study demonstrates that the H-type BSE agent is transmissible by the oronasal route.
These results reinforce the need for ongoing surveillance for classical and atypical BSE to minimize the risk of potentially infectious tissues entering the animal or human food chains.
PRION 2018 CONFERENCE ABSTRACT
Snip...
***> Consumption of L-BSE–contaminated feed may pose a risk for oral transmission of the disease agent to cattle.
***> As a result, since atypical BSE can be reasonably considered to pose a potential background level of risk for any country with cattle, the recycling of both classical and atypical strains in the cattle and broader ruminant populations should be avoided.
***> 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.
Emerg Infect Dis. 2017 Feb; 23(2): 284–287. doi: 10.3201/eid2302.161416 PMCID: PMC5324790 PMID: 28098532 Oral Transmission of L-Type Bovine Spongiform Encephalopathy Agent among Cattle Hiroyuki Okada,corresponding author Yoshifumi Iwamaru, Morikazu Imamura, Kohtaro Miyazawa, Yuichi Matsuura, Kentaro Masujin, Yuichi Murayama, and Takashi Yokoyama Author information Copyright and License information Disclaimer This article has been cited by other articles in PMC. Go to: Abstract To determine oral transmissibility of the L-type bovine spongiform encephalopathy (BSE) prion, we orally inoculated 16 calves with brain homogenates of the agent. Only 1 animal, given a high dose, showed signs and died at 88 months. These results suggest low risk for oral transmission of the L-BSE agent among cattle.
Keywords: atypical bovine spongiform encephalopathy, cattle, L-type, prion, oral transmission, L-BSE, prions and related diseases, zoonoses The epidemic of bovine spongiform encephalopathy (BSE) in cattle is thought to be caused by oral infection through consumption of feed containing the BSE agent (prion). Since 2003, different neuropathologic and molecular phenotypes of BSE have been identified as causing ≈110 cases of atypical BSE worldwide, mainly in aged cattle. Although the etiology and pathogenesis of atypical BSE are not yet fully understood, atypical BSE prions possibly cause sporadic cases of BSE (1).
The L-type BSE (L-BSE) prion has been experimentally transmitted to cattle by intracerebral challenge, and the incubation period was is shorter than that for classical BSE (C-BSE) prions (2–6). The origin of transmissible mink encephalopathy in ranch-raised mink is thought to be caused by ingestion of L-BSE–infected material (7). Although L-BSE has been orally transmitted to mouse lemurs (8), it remains to be established whether L-BSE can be transmitted to cattle by oral infection. We therefore investigated the transmissibility of L-BSE by the oral route and tissue distribution of disease-associated prion protein (PrPSc) in cattle. All experiments involving animals were performed with the approval of the Animal Ethical Committee and the Animal Care and Use Committee of the National Institute of Animal Health (approval nos. 07–88 and 08–010).
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The neuroanatomical PrPSc distribution pattern of orally challenged cattle differed somewhat from that described in cattle naturally and intracerebrally challenged with L-BSE (2–6,11,13,14), The conspicuous differences between the case we report and cases of natural and experimental infection are 1) higher amounts of PrPSc in the caudal medulla oblongata and the spinal cord coupled with that in the thalamus and the more rostral brainstem and 2) relatively low amounts of PrPSc in the cerebral cortices and the olfactory bulb. Furthermore, fewer PrPSc deposits in the dorsal motor nucleus of the vagus nerve may indicate that the parasympathetic retrogressive neuroinvasion pathway does not contribute to transport of the L-BSE prion from the gut to the brain, which is in contrast to the vagus-associated transport of the agent in C-BSE (15). PrPSc accumulation in the extracerebral tissues may be a result of centrifugal trafficking of the L-BSE prion from the central nervous system along somatic or autonomic nerve fibers rather than centripetal propagation of the agent (4,6,9). Consumption of L-BSE–contaminated feed may pose a risk for oral transmission of the disease agent to cattle.
Our study clearly confirms, experimentally, the potential risk for interspecies oral transmission of the agent of L-BSE. In our model, this risk appears higher than that for the agent of classical BSE, which could only be transmitted to mouse lemurs after a first passage in macaques (14). We report oral transmission of the L-BSE agent in young and adult primates. Transmission by the IC route has also been reported in young macaques (6,7). A previous study of L-BSE in transgenic mice expressing human PrP suggested an absence of any transmission barrier between cattle and humans for this particular strain of the agent of BSE, in contrast to findings for the agent of classical BSE (9). Thus, it is imperative to maintain measures that prevent the entry of tissues from cattle possibly infected with the agent of L-BSE into the food chain.
Research Project: Pathobiology, Genetics, and Detection of Transmissible Spongiform Encephalopathies Location: Virus and Prion Research
Title: The agent of H-type bovine spongiform encephalopathy associated with E211K prion protein polymorphism transmits after oronasal challenge
Author item Greenlee, Justin item MOORE, S - Orise Fellow item WEST-GREENLEE, M - Iowa State University
Submitted to: Prion
Publication Type: Abstract Only
Publication Acceptance Date: 5/14/2018
Publication Date: 5/22/2018
Citation: Greenlee, J.J., Moore, S.J., West Greenlee, M.H. 2018. The agent of H-type bovine spongiform encephalopathy associated with E211K prion protein polymorphism transmits after oronasal challenge. Prion 2018, May 22-25, 2018, Santiago de Compostela, Spain. Paper No. P98, page 116. Interpretive Summary:
Technical Abstract: In 2006, a case of H-type bovine spongiform encephalopathy (BSE) was reported in a cow with a previously unreported prion protein polymorphism (E211K). The E211K polymorphism is heritable and homologous to the E200K mutation in humans that is the most frequent PRNP mutation associated with familial Creutzfeldt-Jakob disease. Although the prevalence of the E211K polymorphism is low, cattle carrying the K211 allele develop H-type BSE with a rapid onset after experimental inoculation by the intracranial route.
The purpose of this study was to investigate whether the agents of H-type BSE or H-type BSE associated with the E211K polymorphism transmit to wild type cattle or cattle with the K211 allele after oronasal exposure.
Wild type (EE211) or heterozygous (EK211) cattle were oronasally inoculated with either H-type BSE from the 2004 US H-type BSE case (n=3) or from the 2006 US H-type case associated with the E211K polymorphism (n=4) using 10% w/v brain homogenates.
Cattle were observed daily throughout the course of the experiment for the development of clinical signs.
At approximately 50 months post-inoculation, one steer (EK211 inoculated with E211K associated H-BSE) developed clinical signs including inattentiveness, loss of body condition, weakness, ataxia, and muscle fasciculations and was euthanized.
Enzyme immunoassay confirmed that abundant misfolded protein was present in the brainstem, and immunohistochemistry demonstrated PrPSc throughout the brain.
Western blot analysis of brain tissue from the clinically affected steer was consistent with the E211K H-type BSE inoculum.
With the experiment currently at 55 months post-inoculation, no other cattle in this study have developed clinical signs suggestive of prion disease.
This study demonstrates that the H-type BSE agent is transmissible by the oronasal route.
These results reinforce the need for ongoing surveillance for classical and atypical BSE to minimize the risk of potentially infectious tissues entering the animal or human food chains.
P98 The agent of H-type bovine spongiform encephalopathy associated with E211K prion protein polymorphism transmits after oronasal challenge
Greenlee JJ (1), Moore SJ (1), and West Greenlee MH (2) (1) United States Department of Agriculture, Agricultural Research Service, National Animal Disease Center, Virus and Prion Research Unit, Ames, IA, United States (2) Department of Biomedical Sciences, Iowa State University College of Veterinary Medicine, Ames, IA, United States.
In 2006, a case of H-type bovine spongiform encephalopathy (BSE) was reported in a cow with a previously unreported prion protein polymorphism (E211K).
The E211K polymorphism is heritable and homologous to the E200K mutation in humans that is the most frequent PRNP mutation associated with familial Creutzfeldt-Jakob disease.
Although the prevalence of the E211K polymorphism is low, cattle carrying the K211 allele develop H-type BSE with a rapid onset after experimental inoculation by the intracranial route.
The purpose of this study was to investigate whether the agents of H-type BSE or H-type BSE associated with the E211K polymorphism transmit to wild type cattle or cattle with the K211 allele after oronasal exposure.
Wild type (EE211) or heterozygous (EK211) cattle were oronasally inoculated with either H-type BSE from the 2004 US Htype BSE case (n=3) or from the 2006 US H-type case associated with the E211K polymorphism (n=4) using 10% w/v brain homogenates.
Cattle were observed daily throughout the course of the experiment for the development of clinical signs.
At approximately 50 months post-inoculation, one steer (EK211 inoculated with E211K associated H-BSE) developed clinical signs including inattentiveness, loss of body condition, weakness, ataxia, and muscle fasciculations and was euthanized.
Enzyme immunoassay confirmed that abundant misfolded protein was present in the brainstem, and immunohistochemistry demonstrated PrPSc throughout the brain.
Western blot analysis of brain tissue from the clinically affected steer was consistent with the E211K H-type BSE inoculum.
With the experiment currently at 55 months post-inoculation, no other cattle in this study have developed clinical signs suggestive of prion disease. This study demonstrates that the H-type BSE agent is transmissible by the oronasal route.
These results reinforce the need for ongoing surveillance for classical and atypical BSE to minimize the risk of potentially infectious tissues entering the animal or human food chains.
PRION 2018 CONFERENCE ABSTRACT
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TUESDAY, SEPTEMBER 7, 2021
Classical BSE prions emerge from asymptomatic pigs challenged with atypical/Nor98 scrapie
TUESDAY, OCTOBER 26, 2021
Sporadic Creutzfeldt-Jakob Disease in a Very Young Person Singeltary Reply 2021
WEDNESDAY, OCTOBER 13, 2021
Continuing Enhanced National Surveillance for Prion Diseases in the U.S.
OIE Brazil Confirms TWO More Cases of Mad Cow Disease BSE States of Mato Grosso and Minas Gerais
OIE
Most recent notifications
Country/Territory Disease-Serotype/genotype/subtype Date
Brazil Bovine spongiform encephalopathy 06/09/21
Brazil Bovine spongiform encephalopathy 06/09/21
BRAZIL BSE EEB TSE PRION
CASOS EEB ATÍPICA NO BRASIL
1º CASO: de corte – 13 anos Ø Sertanópolis – Paraná; animal em decúbito – negahvo para raiva; sem alterações no histopatológico Ø 15.06.2012 – diagnóshco posihvo Imunohistoquímica – LANAGRO-PE – Nota Técnica 159/2012; Ø Animal Health and Veterinary Laboratories Agency (AHVLA), Weybridge, United Kingdom – 06.12.2012 - EEB a*pica do 0po H Vaca 2º CASO: corte 12 anos – abate 19.03.14 – vigilância abate emergência – decúbito esternal – fadiga muscular - Notas Técnicas DSA 42 e 52/2014 Ø Porto Esperidião, Mato Grosso; Ø CaracterísHcas – EEB aIpica do Hpo H Ambos no(ficados para OIE.
CASOS EEB ATÍPICA NO BRASIL
3º CASO – 2019 Vaca de corte Nelore – 17 anos Ø Vigilância abate de emergência – animal caído – coleta em 05.04.2019 Ø Nova Canaã do Norte, Mato Grosso Ø Diagnóshco posihvo ELISA – 13.05.2019 - LFDA-PE; Ø Laboratório da Agência de Inspeção de Alimentos Canadenses (CFIA) Alberta, Canada (Laboratório de Referência da OIE) – posihvo ELISA 31.05.2019 Ø CFIA – Canadá – Western Blot – EEB aIpica do Hpo H
OFFICIAL NOTE
Update on an atypical BSE case verified in Mato Grosso Share: Published 06/03/2019 5:41 PM 1- After examining the notification of the occurrence by the International Organization for Animal Health (OIE), this body determined today (3) the closure of the case without changing the Brazilian health status, which remains an insignificant risk for the disease.
2 - The OIE also informed that there will be no supplementary reports on the case.
3 - In the case of China, the Ministry of Agriculture, Livestock and Supply of Brazil has temporarily suspended the issuance of health certificates until the Chinese authority completes its assessment of the information already transmitted about the episode, thus complying with the provisions of the protocol bilateral agreement signed in 2015.
OFFICIAL NOTE
Occurrence of an atypical case of Bovine Spongiform Encephalopathy in Mato Grosso
Published on 05/31/2019 5:20 PM Updated on 05/31/2019 5:25 PM
The Agricultural Defense Secretariat of the Ministry of Agriculture, Livestock and Supply (Mapa) confirms the occurrence, in Mato Grosso, of an atypical case of Bovine Spongiform Encephalopathy ( BSE ). This disease occurs spontaneously and sporadically and is not related to the ingestion of contaminated food.
It is a beef cow, aged 17 years. All BSE- specific risk material was removed from the animal during emergency slaughter and incinerated at the slaughterhouse. Other animal-derived products were identified, located and preventively seized, with no entry of any product into the human or ruminant food chain. Therefore, there is no risk for the population.
It should be noted that the Ministry of Agriculture and the Institute of Agricultural Defense of Mato Grosso (INDEA/MT) immediately began field investigations, with a ban on the original property. All sanitary risk mitigation actions were completed even before the issuance of the final result by a reference laboratory of the World Organization for Animal Health (OIE). After confirmation, this Friday (31), Brazil officially notified the OIE and importing countries, as provided for by international standards.
According to OIE rules, there will be no change in Brazil's risk classification for the disease, which will continue as a country with an insignificant risk, the best possible for BSE . In more than 20 years of surveillance for the disease, Brazil registered only three cases of atypical BSE and no cases of classic BSE .
INTERNATIONAL MARKET
Brazil returns to export beef to China Sales were suspended since June 3 due to notification of an unusual case of BSE in Mato Grosso Share: Published 06/13/2019 11:04 AM Updated on 06/13/2019 1:08 PM China will resume beef imports from Brazil, which had been suspended since June 3, due to the notification of an atypical case of Bovine Spongiform Encephalopathy ( BSE ), detected in Mato Grosso.
China is the only country, among Brazil's importers, that has a sanitary protocol that requires the temporary suspension of meat imports when an atypical case of BSE is detected . The minister of Agriculture, Livestock and Supply, Tereza Cristina, received the news of the reopening of the Chinese market this morning. The minister reaffirmed that she will continue negotiating a new protocol with the Chinese health authorities.
The disease was found in a 17-year-old beef cow. All BSE- specific risk material was removed from the animal during emergency slaughter and incinerated at the slaughterhouse. Other animal-derived products were identified, located and preventively seized, with no entry of any product into the human or ruminant food chain. Therefore, there was no risk for the population.
TUESDAY, SEPTEMBER 27, 2016
Classical Scrapie Diagnosis in ARR/ARR Sheep in Brazil
Acta Scientiae Veterinariae, 2015. 43(Suppl 1): 69.
CASE REPORT Pub. 69
ISSN 1679-9216
1
Received: 4 August 2014 Accepted: 19 December 2014 Published: 6 February 2015
1Programa de Pós-graduação em Ciências Veterinárias (PPGCV), Faculdade de Veterinária (FaVet), Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil. 2Setor de Patologia Veterinária (SPV), Departamento de Patologia Clínica Veterinária (DPCV), FAVET, UFRGS, Porto Alegre, RS, Brazil. 3Departamento de Ciências Morfológicas, Instituto de Ciências Básicas da Saúde (ICBS), UFRGS, Porto Alegre, RS. CORRESPONDENCE: J.S. Leal [julianoob@gmail.com - Tel.: +55 (51) 3308 3631]. Setor de Patologia Veterinária, FAVET, UFRGS. Av. Bento Gonçalves n. 9090, Bairro Agronomia. CEP 91540-000 Porto Alegre, RS, Brazil.
Classical Scrapie Diagnosis in ARR/ARR Sheep in Brazil
Juliano Souza Leal1,2, Caroline Pinto de Andrade2, Gabriel Laizola Frainer Correa2, Gisele Silva Boos2, Matheus Viezzer Bianchi2, Sergio Ceroni da Silva2, Rui Fernando Felix Lopes3 & David Driemeier2
ABSTRACT
Background: Scrapie is a transmissible spongiform encephalopathy (TSE) that affects sheep flocks and goat herds. The transfer of animals or groups of these between sheep farms is associated with increased numbers of infected animals and with the susceptibility or the resistance to natural or classical scrapie form. Although several aspects linked to the etiology of the natural form of this infection remain unclarified, the role of an important genetic control in scrapie incidence has been proposed. Polymorphisms of the PrP gene (prion protein, or simply prion), mainly in codons 136, 154, and 171, have been associated with the risk of scrapie. Case: One animal from a group of 292 sheep was diagnosed positive for scrapie in the municipality of Valparaíso, state of São Paulo, Brazil. The group was part of a flock of 811 free-range, mixed-breed Suffolk sheep of the two genders and ages between 2 and 7 years from different Brazilian regions. Blood was collected for genotyping (for codons 136, 141, 154 and 171), and the third lid and rectal mucosa were sampled for immunohistochemistry (IHC) for scrapie, from all 292 animals of the group. IHC revealed that seven (2.4%) animals were positive for the disease. Collection of samples was repeated for 90 animals, among which the seven individuals diagnosed positive and 83 other animals that had some degree of kinship with those. These 90 sheep were sacrificed and necropsied, when samples of brain (obex), cerebellum, third eyelid, rectal mucosa, mesenteric lymph node, palatine tonsil, and spleen were collected for IHC. The results of IHC analyses carried out after necropsy of the seven positive animals submitted to the second collection of lymphoreticular tissue and of the 83 animals with some degree of kinship with them confirmed the positive diagnosis obtained in the first analysis, and revealed that three other sheep were also positive for scrapie. Samples of 80 animals (89%) were negative for the disease in all organs and tissues analyzed. In turn, 10 sheep (11%) were positive, presenting immunoreactivity in one or more tissues. Genotyping revealed the presence of four of the five alleles of the PrP gene commonly detected in sheep: ARR, ARQ, VRQ and ARH. These allele combinations formed six haplotypes: ARR/ARR, ARR/ARQ, ARH/ARH, ARQ/ARH, ARQ/ARQ and ARQ/VRQ. Animals were classified according to susceptibility to scrapie, when 8.9% of the genotyped sheep were classified into risk group R1 (more resistant, with no restriction to breeding). In turn, 40% of the animals tested ranked in groups R4 and R5 (genetically very susceptible, cannot be used for breeding purposes). Discussion: The susceptibility of sheep flocks depends on the genetic pattern of animals and is determined by the sequence of the gene that codifies protein PrP. Additionally, numerous prion strains are differentiated based on pathological and biochemical characteristics, and may affect animals differently, depending on each individual’s genotype. Most epidemiologic data published to date indicate that animals that carry the ARR/ARR genotype are less susceptible to classical scrapie. However, in the present study, the fact that two scrapie-positive sheep presented the haplotype ARR/ARR indicates that this genotype cannot always be considered an indicator of resistance to the causal agent of the classical manifestation of the disease. The coexistence in the same environment of several crossbred animals from different flocks and farms, which characterizes a new heterogeneous flock, may have promoted a favorable scenario to spread the disease, infecting animals in the most resistant group.
Keywords: biopsy, scrapie, TSEs, immunohistochemistry.
DISCUSSION
The susceptibility of sheep flocks to scrapie depends largely on the genetic pattern of the animal, and is determined mainly by the sequence of the gene that codifies the PrP protein, since there are several polymorphisms that affect the conversion of the cell protein PrPC to its pathological form, PrPSc [8, 9]. Nevertheless, it is not possible to consider the occurrence of only one form of ovine prion, since there are numerous prion strains with different pathological and biochemical characteristics that may affect animals distinctively, depending on their genotypes [1, 30]. In the present study, the frequency of codon VRQ was very low (2.2%), confirming previous findings, which revealed that the alleles ARR and ARQ prevail in Suffolk sheep, and that the allele ARH sometimes is detected [12, 32]. The high sensitivity of homozygous VRQ carriers or of individuals with ARQ haplotypes has also been reported in the literature [24]. This condition raises concerns about susceptibility from the epidemiological perspective, since the allele VRQ, which is rare or absent in breeds like Suffolk, was present in two animals, one of which was positive for scrapie. Most epidemiological and genetic data published indicate that sheep carrying the haplotype ARR/ ARR are less susceptible to classical form, while animals with the haplotype VRQ in homozygosis or with ARQ haplotypes are highly susceptible [24]. This hypothesis is supported by genotyping data for thousands of sheep with the disease around the world. For example, a study carried out in Japan described a classical scrapie case in one ARR/ARR sheep [16]. Sensitivity of ARR/ARR sheep in a scenario of oral exposure to the disease has also been reported [3]. Atypical cases were observed in ARR/ARR animals [11, 42].
Polymorphisms at codon positions 136, 154 and 171 are not the only ones associated with resistance or susceptibility to scrapie [33]. An analysis of the variation of codon positions 136 and 171, for instance, showed that each has several adjacent polymorphic sites and may codify up to four amino acids [7, 50]. The atypical scrapie form, characterized by strain Nor98 [6], is more frequently detected in AHQ animals that carry a polymorphism in codon 141, and has not been described in Suffolk sheep in Brazil [2]. This atypical form expresses phenylalanine (F), instead of leucine (L) in the form L141F [6, 37, 46].
However, although it is generally acceptable that classical scrapie is an infectious and contagious disease [14], contagion with the atypical form is questionable in light of the fact that the specific marker for the atypical manifestation of the disease is detected outside the central nervous system [5, 20, 29], even in cases experimentally transmitted to transgenic mice [35] and sheep [47]. Several studies have demonstrated that susceptibility to the atypical form is consistently associated with PrP codons 141 (L/F) and 154 (R/H) [6, 42]. In fact, studies have proposed the hypothesis that this form may evolve when the animal is not exposed to the infectious agent [5, 18, 29, 48], given the limited knowledge of the physiopathology of this manifestation of the disease [19].
In the present study, two (2/8) positive animals presented the haplotype ARR/ARR, which is considered to be the least susceptible and therefore responsible for the lowest risk of scrapie. However, like all sheep that were genotyped, these animals did not present any change in lysine in codon position 141. This change (that is, when lysine is replaced by phenylalanine) has been associated with atypical scrapie in Suffolk sheep [6]. Therefore, these two ARR/ARR sheep do not fit in the genotypic characteristics of sheep that may commonly present the atypical form. It is possible that the presence of several crossbred animals of different flocks and farms in the same environment, which characterizes an heterogeneous flock, has created the favorable conditions for the disease to evolve and spread, infecting the more susceptible animals.
The variation in the frequency of the PrP genotype between flocks has been identified as a real risk factor for the disease [4]. The introduction of adult sheep free of scrapie in contaminated flocks is believed to allow lateral transmission, even between adult animals with less susceptible genotypes [40, 45], although young sheep are more predisposed [43]. Other reasons behind differences in occurrence include the stress caused during husbandry and large population numbers [26]. Additionally, the lack of a defined epidemiological pattern and the different strains of the causal agent play an important role in inter-flock variability [40]. Several models were based on the assumption that outbreak duration is influenced by flock size and by the frequency of the PrP genotype in one flock [25, 26, 38, 51]. Commercial flocks with high genetic diversity, mainly in codons other than 136, 154 and 171, are more consistently affected. In these animals, the onset of clinical manifestations occurs at significantly different ages, with means varying from 2 to 5.7 years, due to noteworthy dissimilarities in age and PrP genotype profiles [40]. The purchase of infected animals has been pointed out as the main scrapie infection mechanism in flocks [27, 41].
*** The diagnosis of scrapie in two homozygous ARR/ARR sheep indicates that the resistance of this genotype to the classical form of the disease is debatable. Although scrapie in these animals is rare, the cases presented in this case report lend strength to the notion that its occurrence depends on a combination of infectious factors, including differences in biological and biochemical properties in the natural hosts to this prion.
MANUFACTURERS 1VMRD Pullman Albion Road. Pullman, WA, USA. 2Qiagen. Hilden, Germany. 3InvitrogenTM. São Paulo, Brazil. 4Life TechnologiesTM. Gaithersburg, MD, USA. 5InvitrogenTM. Carlsbad, CA, USA. 6Applied Biosystems Inc. Foster City, CA, USA. Declaration of interest. The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.
Scrapie diagnosis in a goat and four Santa Inês sheep from the same herd in Brazil
J.S. LealG.L.F. CorreaG.S. BoosM.V. BianchiF.M. BoabaidR.F.F. LopesD. Driemeier
Diagnóstico de scrapie em um caprino e quatro ovinos Santa Inês de um mesmo rebanho no Brasil
Scrapie is a fatal and progressive transmissible spongiform encephalopathy (TSE) of natural occurrence in sheep and goats. The suspicion of scrapie may be based on clinical signs; however, the detection of pathological features of the prionic protein (PrP) in target tissues is necessary to diagnose the disease. The presence of an abnormal protein form (PrPSc) in lymphoreticular and nervous tissues is an important characteristic in diagnosis. This paper reports a case of scrapie in a flock of 55 Suffolk crossbred sheep, 19 Santa Inês sheep and 21 goats in the Mato Grosso state, midwestern Brazil. The animals were euthanized after the confirmation of a scrapie case with clinical signs in a Suffolk sheep in the same farm. Samples of brainstem at the level of the obex and lymphoid issues like palatine tonsils, mesenteric lymph nodes, third eyelid fixed in formalin 10% were processed for histological examination. Histological examination with hematoxylin and eosin did not show any microscopic changes in samples. Immunohistochemistry (IHC) examination to detect anti-prion PrPSc was performed in lymphoid tissues. Scrapie diagnosis was confirmed based on IHC positive results for PrPSc in lymphoid tissues of a crossbreed goat and four Santa Inês sheep, without any clinical scrapie signs. IHC showed positive staining in at least three lymphoid germinal centers in goat mesenteric lymph node, palatine tonsil, and third eyelid samples. The mesenteric lymph node, and tonsil samples of all sheep showed positive immunostaining, and only one sheep showed positive staining in lymphoid follicles in the third eyelid. Scrapie diagnosis using IHC in fixed samples of lymphoreticular tissue is technically feasible to detect the disease in both goats and sheep, as a form of pre-clinical diagnosis. The results indicate that the herd was infected by a sheep coming from another herd where scrapie had been diagnosed before.
scrapie; prion; diseases of small ruminants; immunohistochemistry; lymphoid tissues
WEDNESDAY, JUNE 12, 2019
FINAL REPORT OF AN AUDIT CONDUCTED IN BRAZIL MAY 15 TO JUNE 2, 2017 EVALUATING THE FOOD SAFETY SYSTEMS GOVERNING MEAT PRODUCTS EXPORTED TO THE UNITED STATES OF AMERICA
TUESDAY, MARCH 26, 2019
Joint Statement from President Donald J. Trump USA and President Jair Bolsonaro Brazil FOREIGN POLICY BSE TSE Prion aka mad cow disease
SATURDAY, JUNE 01, 2019
Brazil reports another cases of mad cow disease atypical BSE TSE Prion
TUESDAY, SEPTEMBER 27, 2016
Classical Scrapie Diagnosis in ARR/ARR Sheep in Brazil
Acta Scientiae Veterinariae, 2015. 43(Suppl 1): 69.
MONDAY, AUGUST 1, 2016
USDA Announces Reopening of Brazilian Market to U.S. Beef Exports and the Potential for Transmissible Spongiform Encephalopathy TSE prion disease
MONDAY, MAY 5, 2014
Brazil BSE Mad Cow disease confirmed OIE 02/05/2014
Monday, May 5, 2014
Brazil 2nd BSE Mad Cow disease confirmed OIE 02/05/2014
Thursday, April 24, 2014
Brazil investigates possible BSE mad cow case
WEDNESDAY, JANUARY 29, 2014
Another Suspect case of Creutzfeldt-Jakob disease investigated in Brazil
THURSDAY, SEPTEMBER 26, 2013
Brazil evaluate the implementation of health rules on animal by-products and derived products SRM BSE TSE PRION aka MAD COW DISEASE
Wednesday, December 19, 2012
Scientific Report of the European Food Safety Authority on the Assessment of the Geographical BSE Risk (GBR) of Brazil
***> Friday, December 07, 2012
***> ATYPICAL BSE BRAZIL 2010 FINALLY CONFIRMED OIE 2012
SATURDAY, SEPTEMBER 4, 2021
Brazil Confirms TWO More Cases of Mad Cow Disease BSE States of Mato Grosso and Minas Gerais
Terry S. Singeltary Sr.
posted by Terry S. Singeltary Sr. at
4:57 PM
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