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![A, discrimination of different types of bovine spongiform encephalopathy (BSE). Biochemical typing of PrP res by Western blot reveals a slightly higher molecular mass of PrP res in high-type BSE (H-BSE) as compared with classical BSE (C-BSE) and bovine amyloidotic spongiform encephalopathy (BASE). A BSE-negative sample served as control. Molecular masses of a protein marker are indicated on the left in kDa. B, the relative intensities of BASE, H-BSE, and C-BSE PrP res moieties derived from the Western blot results shown in panel A. Note that the diglycosylated moiety in BASE is less prominent when compared with H-BSE and C-BSE. C, amyloidotic PrP d plaques in immunohistochemistry are characteristic for BASE-affected cattle, whereas (D) PrP d deposition pattern in H-BSE (zebu [Bos indicus], olivary nuclei) resembles that in C-BSE.](profile/Dagmar-Heim/publication/47815316/figure/fig1/AS:601708849819659@1520469977988/A-discrimination-of-different-types-of-bovine-spongiform-encephalopathy-BSE.png)
A, discrimination of different types of bovine spongiform encephalopathy (BSE). Biochemical typing of PrP res by Western blot reveals a slightly higher molecular mass of PrP res in high-type BSE (H-BSE) as compared with classical BSE (C-BSE) and bovine amyloidotic spongiform encephalopathy (BASE). A BSE-negative sample served as control. Molecular masses of a protein marker are indicated on the left in kDa. B, the relative intensities of BASE, H-BSE, and C-BSE PrP res moieties derived from the Western blot results shown in panel A. Note that the diglycosylated moiety in BASE is less prominent when compared with H-BSE and C-BSE. C, amyloidotic PrP d plaques in immunohistochemistry are characteristic for BASE-affected cattle, whereas (D) PrP d deposition pattern in H-BSE (zebu [Bos indicus], olivary nuclei) resembles that in C-BSE.
Source publication
Since 1987, when bovine spongiform encephalopathy (BSE) emerged as a novel disease in cattle, enormous efforts were undertaken to monitor and control the disease in ruminants worldwide. The driving force was its high economic impact, which resulted from trade restrictions and the loss of consumer confidence in beef products, the latter because BSE...
Contexts in source publication
Context 1
... French cases showed unglycosylated PrP res in the caudal brainstem and was of conspicuously higher molecular mass than classical BSE is. Antibody- binding studies revealed that this was due to more N- terminal PK cleavage of PrP d , compared with that in classical BSE, 22 similar to the situation in classical scrapie. Such isolates were later designated H-BSE, where H refers to the higher molecular mass of the PrP res . By contrast, in the Italian cases, the molecular mass of PrP res was slightly lower than classical BSE is and, more obvious, the monoglycosylated PrP res band was at least equally intense as the diglycosylated one. In these animals, whole brains were sampled, and the tissues collected were also suitable for IHC analysis. The morphologic PrP d deposition differed from those previously observed in BSE cases. Relatively few deposits were found in the obex region but many more occurred in the more rostral structure of the brain, namely, in the thalamus and the olfactory bulb. The deposits predominated in the form of amyloid- like plaques, which were also reported for TSEs in human beings, such as GSS, sCJD, kuru, and vCJD, but were not previously reported in cattle (Fig. 2C). 46 The Italian investigators designated this newly identified disease phenotype bovine amyloidotic spongiform encephalopathy ...
Context 2
... the availability of in situ PrP d detection methods, it has been shown, although only in a limited number of cattle with clinical BSE, that the PrP d distribution throughout the neuraxis corre- sponded with the distribution pattern of the vacuolar and spongiform changes. 56,86 More comprehensive case numbers were analyzed systematically at the level of the obex. The target nuclei defined for the histopathologic diagnosis consistently showed dis- tinctive immunolabeling patterns in IHC. 44,45,134 These nuclei were also the structures where PrP d was detectable in the absence of lesions in preclinical BSE cases that had been first identified through herd- culling schemes. 145,148,160 The typical BSE WB profile has a 3-band pattern with a clearly more prominent diglycosylated PrP res band, as compared with the monoglycosylated band ( Fig. 2A, C-type), 95 and was, therefore, distinct from those observed in most natural, classical scrapie cases. However, as the profound analysis of the molecular PrP d characteristics has not been part of routine WB confirmatory tests in BSE-affected cattle until recently, the extent of variation in these characteristics among affected animals and among brain regions within the same individual has been poorly addressed. More precise investigations now underpin the understanding that molecular PrP res phenotype in classical BSE cases indeed appears well conserved 7,40,101 and independent of the brain region under investigation. 166 Biological strain typing by transmission of individ- ual samples from BSE-affected cattle to inbred mouse lines has been accomplished for 12 cases from the United Kingdom 31,53 and for 2 cases from Switzerland (M. Bruce, unpublished data) and revealed a closely similar disease phenotype with respect to incubation times and lesions ...
Context 3
... these first reports, some 50 cases similar to BASE (also referred to as L-BSE) or H-BSE have been recorded in a series of countries, either newly identified or by analyzing BSE cases retrospectively while focusing on their specific features (Table 3). All were linked by their falling within the age range of 8- 20 years and were, therefore, older in comparison to the average age of 5-6 years in C-BSE. Except for a 19-year-old zebu bull (Bos indicus), which was identified as a clinical suspect in a zoo in Switzerland and later classified as having H-BSE, 151,166 these atypical cases have been detected exclusively by active surveillance. Similar to atypical scrapie, this limited the availability of reliable information on the clinical signs and prevented comprehensive examination of neuronal and extraneuronal pathology. Of all H-BSE cases, a complete brain was available only for the zebu, and despite distinct biochemical PrP res features, the histopathologic lesions and the morphologic PrP d depositions in the brain were similar to classical BSE (Fig. ...
Context 4
... the present time, the classification as C-BSE, H- BSE, and BASE relies mainly on the biochemical properties of PrP res . A systematic molecular typing strategy has recently been proposed and validated. 101 Besides the comparison of the electrophoretic profile, this approach also includes the analysis of reactivity patterns with different PrP-specific monoclonal anti- bodies in WB. In this experimental setup, H-type BSE reveals 1) an unglycosylated PrP res of a molecular mass of about 1.5 kD higher, compared with that in C-BSE (Fig. 2A); 2) reactivity with N-terminal antibodies that bind to the amino acids 101-107 of the bovine prion protein; and 3) an additional band migrating at about 10-12 kD and a complex banding pattern in the range of 18-30 kD with antibodies that bind to the PrP C-terminus. The latter, it has been proposed, 21 results from overlapping signals with an additional glycosylated C-terminal fragment of PrP res , which is missing in C-BSE and BASE. Differences in the molecular mass of PrP res between BASE and C- BSE are a less-robust criterion, and the identification of BASE relies primarily on the comparison of band intensities from the different PrP res glycoforms (Fig. ...
Context 5
... the present time, the classification as C-BSE, H- BSE, and BASE relies mainly on the biochemical properties of PrP res . A systematic molecular typing strategy has recently been proposed and validated. 101 Besides the comparison of the electrophoretic profile, this approach also includes the analysis of reactivity patterns with different PrP-specific monoclonal anti- bodies in WB. In this experimental setup, H-type BSE reveals 1) an unglycosylated PrP res of a molecular mass of about 1.5 kD higher, compared with that in C-BSE (Fig. 2A); 2) reactivity with N-terminal antibodies that bind to the amino acids 101-107 of the bovine prion protein; and 3) an additional band migrating at about 10-12 kD and a complex banding pattern in the range of 18-30 kD with antibodies that bind to the PrP C-terminus. The latter, it has been proposed, 21 results from overlapping signals with an additional glycosylated C-terminal fragment of PrP res , which is missing in C-BSE and BASE. Differences in the molecular mass of PrP res between BASE and C- BSE are a less-robust criterion, and the identification of BASE relies primarily on the comparison of band intensities from the different PrP res glycoforms (Fig. ...
Citations
... Bovine spongiform encephalopathy (BSE) is a transmissible spongiform encephalopathy caused by a misfolded form of the prion protein. Atypical BSE is widely considered to be a spontaneously occurring or sporadic prion disease (1)(2)(3)(4). Atypical BSE tends to occur in older cattle and has a low incidence, with steady occurrence over time. Two variants of atypical BSE are characterized as low (L-BSE) or high (H-BSE) based on the relative size of the unglycosylated fragment and its consequent appearance on western blot (4). ...
... Human prion diseases, such as Creutzfeldt-Jakob Disease (CJD), have been categorized into three etiologies: genetic, sporadic, and acquired (17). It has long been theorized that H-BSE is sporadic in origin (2). Shorter incubation periods in cattle with a K211 allele suggests a better conversion efficiency for the K211 prion protein into its misfolded form. ...
In 2006, a case of atypical H-type BSE (H-BSE) was found to be associated with a germline mutation in the PRNP gene that resulted in a lysine substitution for glutamic acid at codon 211 (E211K). The E211K amino acid substitution in cattle is analogous to E200K in humans, which is associated with the development of genetic Creutzfeldt-Jakob disease (CJD). In the present study, we aimed to determine the effect of the EK211 prion protein genotype on incubation time in cattle inoculated with the agent of H-BSE; to characterize the molecular profile of H-BSE in KK211 and EK211 genotype cattle; and to assess the influence of serial passage on BSE strain. Eight cattle, representing three PRNP genotype groups (EE211, EK211, and KK211), were intracranially inoculated with the agent of H-BSE originating from either a case in a cow with the EE211 prion protein genotype or a case in a cow with E211K amino acid substitution. All inoculated animals developed clinical disease; post-mortem samples were collected, and prion disease was confirmed through enzyme immunoassay, anti-PrPSc immunohistochemistry, and western blot. Western blot molecular analysis revealed distinct patterns in a steer with KK211 H-BSE compared to EK211 and EE211 cattle. Incubation periods were significantly shorter in cattle with the EK211 and KK211 genotypes compared to the EE211 genotype. Inoculum type did not significantly influence the incubation period. This study demonstrates a shorter incubation period for H-BSE in cattle with the K211 genotype in both the homozygous and heterozygous forms.
... In this study, it was decided to remove atypical BSE cases from the analysis. These were removed because they are likely to have a different aetiology to classical BSE and, while it is still largely unclear, it is likely that atypical BSE arises spontaneously, i.e. without any exposure to the infectious agent (Seuberlich et al., 2010). ...
The emergence and epidemic of classical Bovine Spongiform Encephalopathy (cBSE) represents one of the most important and unique episodes in disease control of a zoonotic disease due to its novelty and its impact. Since its detection in 1986 in the United Kingdom, it has also been detected in 25 countries. The novel nature of its infectious agent and the discovery of its zoonotic potential (causing the new variant of Creutzfeldt-Jakob disease in humans) caught the food industry, policy makers, scientific community and consumers off guard, with concerns over massive human exposure and health impact. Thirty-five years later, and following the feed bans of mammalian protein to livestock in 1996, the epidemic is now in its final stages, with expectations of occasional cases emerging until the year 2026. In the last six years, two cBSE cases from animals Born After the Reinforced feed Ban (BARB) have been identified in Scotland and England, delaying their application for BSE Negligible status. This paper provides a current and historical analysis of the epidemic situation in Great Britain and a review of the policies implemented, the impact of the disease since its emergence and the possible factors explaining the occurrence of new cases.
The analysis and review reinforce the hypothesis that cBSE BARB cases occurrence may not be spontaneous, yet there remains much uncertainty on their aetiology. To date, 181,122 cBSE cases have been detected in Great Britain, of which 178 are BARB cases; and 178 human cases of the new variant of Creutzfeldt-Jakob have been diagnosed. The disease triggered major policy responses in the country, and worldwide, that have transformed the industry and our approach to animal health. Almost all its impact is originated from societal reactions to the disease, from disposal of animals and products, to reduction of the national herd and its production efficiency, losses through trade restrictions and reduction in market prices and consumers' confidence, hardening of cleaning and control procedures in farms and hospitals, generation of heavy government investment plans through numerous support, surveillance and research schemes, and political and societal changes. BSE is an example of major system shock to a food industry, but which experience has resulted in better traceability systems of animals, increase capacity to develop robust diagnostic methods, numerous lessons learnt on policy coordination, implementation and communication, increased society awareness on food systems and overall improved the country's preparedness to future epidemics.
... A principal fonte de transmissão é através da ingestão de alimentos contendo proteínas e gordura de origem animal, tal como a farinha de carne e ossos, dentre outros (González, 2000). Grandes esforços foram feitos para o controle da EEB, após um surto epidêmico no mundo da forma clássica da doença no final do século XX, principalmente após o reconhecimento de que se tratava de uma doença transmissível para humanos, através da ingestão de tecidos infectados (Seuberlich et al., 2010). ...
Objetivou-se caracterizar o sistema de vigilância epidemiológica da Encefalopatia Espongiforme Bovina (EEB) no estado do Maranhão, no período de 2016 a 2019. A pesquisa foi realizada por meio de um estudo descritivo, com uma abordagem quantitativa, utilizando dados secundários provenientes do registro das fiscalizações às propriedades rurais executadas pelo Serviço Veterinário Oficial. No período estudado foram realizadas 526 fiscalizações para vigilância dos alimentos fornecidos a ruminantes em estabelecimentos de criação, sendo 98,9% fiscalizações provenientes da vigilância ativa e 1,1% de vigilância passiva. Dos 217 municípios do estado do Maranhão, em 20,3% foram realizadas fiscalizações com registro de três casos de ingestão de proteína de origem animal (cama de aviário) por bovinos com confirmação laboratorial no período avaliado. Com relação à caracterização das propriedades observou-se que 54,8% das fiscalizações foram realizadas em propriedades com bovinocultura de corte; 56,7% com sistema de criação extensivo; 60,3% com alimentação dos ruminantes a base de pastagem associada a concentrados e/ou suplementos. Constatou-se, ainda, que 20,0% das fiscalizações foram realizadas em propriedades com presença de avicultura industrial/comercial, 18,3% com presença de cama de aviário, sendo que em cinco propriedades (1,0%) houve relato do uso de cama de aviário na alimentação de ruminantes. Os resultados apontam a necessidade da vigilância contínua em propriedades identificadas como potencialmente de risco quanto ao possível uso de proteínas de origem animal na alimentação de ruminantes no estado do Maranhão, pois apesar da sua proibição, ainda é praticado o uso de cama de aviário para alimentar bovinos.
... The spread of BSE agent to small ruminants is a major issue in the surveillance of TSEs because BSE passage into a new host may change strain properties, make it difficult to recognize the original strain, and increasing the risk of epidemic spread 8 . Since 2005, two natural BSE cases have been reported in goats 9,10 . ...
Since 2005, two cases of natural bovine spongiform encephalopathies (BSE) have been reported in goats. Furthermore, experimental transmissions of classical (C-BSE) and atypical (L-BSE) forms of BSE in goats were also reported. To minimize further spreading of prion diseases in small ruminants the development of a highly sensitive and specific test for ante-mortem detection of infected animals would be of great value. Recent studies reported high diagnostic value of a second generation of cerebrospinal fluid (CSF) Real-Time Quaking-Induced Conversion (RT-QuIC) assay across a wide spectrum of human prions. Here, we applied this improved QuIC (IQ-CSF) for highly efficient detection of TSEs prion protein in goat cerebrospinal fluid. IQ-CSF sensitivity and specificity were evaluated on CSF samples collected at disease endpoint from goats naturally and experimentally infected with scrapie or bovine isolates of C-BSE and L-BSE, respectively. Next, CSF samples collected from L-BSE infected goats during pre-symptomatic stage were also analysed. PrPL-BSE associated seeding activity was detected at early time points after experimental inoculation, with an average time of 439 days before clinical symptoms appeared. Taken together these data are indicative of the great potential of this in vitro prion amplification assay as ante-mortem TSE test for live and asymptomatic small ruminants.
... The is turned off in adulthood, do not develop clinical signs of typical strains, known as H (high) and L (low) type, are BSE. In fact, depletion of PrPC in mice with established diagnosed rarely, typically in cattle of 8-20 years of age prion infection has been shown to reverse early and appear to be sporadic and arise spontaneously [9,10]. ...
The principal objective of this seminar paper is to highlight the public health and economic significance of Bovine Spongiform Encephalopathy (BSE). Bovine spongiform encephalopathy is zoonotic and fatal neurological disease of adult cattle caused by unique infectious proteins known as prions associated with ingestion of infectious material in meat and bone meal made from BSE-infected animals. The disease has both an economic and public health importance. The disease results in economic loss through death of cattle and ban of trade. The consumption of food of bovine origin contaminated with the agent of BSE has been strongly linked to the occurrence of Variant Creutzfeldt-Jakob disease in humans. It is a fatal disease that can infect a person for many years before making them sick by destroying brain cells. The disease can be diagnosed using histopathology, immunohistochemistry and rapid test techniques. Banning of infected meat and bone meals are the main prevention and control measure of the disease. In conclusion, the disease remains challenging because the disease is chronic and fatal, lack of cost-effective diagnostic tools in live animals and humans and lack of effective vaccine and treatment. In light of this conclusion, reinforcing banning on the use of infected meat and bone meal, establishing surveillance system and policy and collaborative research toward developing vaccine and treatment are recommended to prevent and control the disease.
... Available data suggest that these atypical BSE types occur spontaneously at a low but constant level (Seuberlich, Heim, & Zurbriggen, 2010;Simmons et al., 2017), and experimental data have raised the hypothesis that they could have been the origin of the C-type BSE epidemic (Baron et al., 2011;Beringue et al., 2007;Capobianco et al., 2007). ...
Bovine spongiform encephalopathy (BSE) is caused by different prion strains that are discriminated by the molecular characteristics of the pathological prion protein. In 2011, Switzerland reported two presumptive cases of BSE in cattle with a prion protein phenotype different from previously described strains, and it was unclear whether these findings were related to a transmissible disease and have implications on animal and public health. In this study, brain tissues of these cases were inoculated into transgenic mice expressing the bovine prion protein (BoPrP‐Tg110) and into cattle. Clinical and pathological investigations as well as molecular testing did not provide evidence for the presence of BSE in the Swiss cases after two passages in BoPrP‐Tg110 mice and a challenge period of 3.5 years in cattle. This lack of disease transmission suggests that the Swiss 2011 cases were not affected by a prion disease and were unrelated to the feed‐born BSE epidemic.
... Scholars are currently studying the factors affecting food safety and the generation mechanism of food safety risk from the following perspectives: the transformation of governments' regulatory responsibilities (Hobbs, Fearne, & Spriggs, 2002;Wang & Chen, 2016;Wang et al., 2015), biological invasion caused by food trade (Morris, 2002), legislative problem in food safety (B an ati, 2003), the policy on food safety (Swarte & Donker, 2005), the application of raw materials and technology in food production along with the advancement of science and technology (Kinsey, 2005), the estimation method on food safety (Dom enech, Escriche, & Martorell, 2008;K€ onig & Smith, 2010). Some scholars have studied the forewarning model and the technological means on food safety (Łozowicka, Rutkowska, Jankowska, Kaczy nski, & Hrynko, 2012;Seuberlich, Heim, & Zurbriggen, 2010;Taylor, 2013;Tomperi, Pelo, & Leivisk, 2013). Others proposed scientific and effective management systems on food safety risk through objective management (Gorris, 2005;Stringer, 2005), decision support system (Jacxsens et al., 2010), safety management system, and genome analysis (Begley & Hill, 2010). ...
This paper introduces the SIRS contagion model of food safety risk considering the entry rate, the normal bankruptcy rate, the abnormal bankruptcy rate, and other correlated parameters of food enterprise. The influences of these correlated factors on the contagion of food safety risk is discussed and theoretically analyzed. Computer simulation was performed to measure the entry rate of food enterprises, the normal bankruptcy rate, the abnormal bankruptcy rate, the re‐violation rate, the recovery rate, and the connectivity of food enterprises. The study found that: (a) the inhibitory effect of the normal bankruptcy rate on food safety risk contagion is the most significant; (b) the abnormal bankruptcy rate and the recovery rate can also constrain food safety risk, but the re‐violation rate will scale up the food safety risk; (c) a negative correlation exists between the entry rate and the contagion threshold of food safety risk, and a positive correlation is observed between the entry rate and the contagion scale of food safety risk; (d) with the increasing number of food enterprises' business partners, the contagion scale of food safety risk will increase.
Practical applications
This study is significant in supervising and managing the food market because it analyzes the contagion mechanism and the influence factors of food safety risk in the food supply network. According to the research results, we could take corresponding effective actions which introduced in the research to control the contagion scale of food safety risk and to guard the safety of food market.
... Passive surveillance for neuroinfectious diseases in cattle was very effective during the BSE epidemic in the 1990s and early 2000s in Switzerland (Heim et al., 1997;Seuberlich et al., 2010). However, reporting and diagnostic follow-up of neurologically diseased cattle have declined significantly with decreasing BSE case numbers . ...
Neuroinfectious diseases in livestock represent a severe threat to animal health, but their prevalence is not well documented and the etiology of disease often remains unidentified. The aims of this study were to generate baseline data on the prevalence of neuroinfectious diseases in cattle in Switzerland by neuropathological survey, and to identify disease-associated pathogens. The survey was performed over a 1-year period using a representative number of brainstem samples (n = 1816) from fallen cattle. In total, 4% (n = 73) of the animals had significant lesions, the most frequent types of which were indicative of viral (n = 27) and bacterial (n = 31) etiologies. Follow-up diagnostics by immunohistochemistry, PCR protocols and next-generation sequencing identified infection with Listeria monocytogenes (n = 6), ovine herpesvirus 2 (n = 7), bovine astrovirus CH13 (n = 2), bovine herpesvirus 6 (n = 6), bovine retrovirus CH15 (n = 2), posavirus 1 (n = 2), and porcine astroviruses (n = 2). A retrospective questionnaire-based investigation indicated that animals’ owners observed clinical signs of neurological disease in about one-third of cases with lesions, which was estimated to correspond to approximately 85 cases per year in the adult fallen cattle population in Switzerland. This estimate stands in sharp contrast to the number of cases reported to the authorities and reveals a gap in disease surveillance. Systematic neuropathological examination and follow-up molecular testing of neurologically diseased cattle could significantly enhance the efficiency of disease detection for the purposes of estimating the prevalence of endemic diseases, identifying new or re-emerging pathogens, and providing “early warnings” of disease outbreaks.
... Apesar dos esforços para evitar a entrada de tecidos bovinos potencialmente infectados na cadeia alimentar humana, em 1996 foi comprovada a transmissão da EEB a humanos, causando a variante da doença de Creutzfeldt-Jakob (vDCJ) (WILL et al., 1996), resultando em um impacto devastador na indústria pecuária do Reino Unido e no mundo (BROWN et al., 2001). Devido a esse grande impacto econômico e por ser uma zoonose, as autoridades sanitárias implantaram medidas para proteger a saúde humana e animal, que incluíram a proibição da alimentação de ruminantes com alguns subprodutos de origem animal, a proibição do consumo de carne e subprodutos de animais doentes, a remoção do material de risco específico (MRE) das carcaças de bovinos, vigilância epidemiológica e controle de subprodutos e importação de animais vivos (SEUBERLICH et al., 2010). Devido a algumas características da doença, como o longo período de incubação, levaram-se mais de duas décadas para que ela fosse finalmente controlada. ...
... A identificação de outras formas de EEB pode ser atribuída ao aumento da vigilância das EET em todo o mundo, especialmente na Europa (SEUBERLICH et al., 2010). A descoberta de formas atípicas da EEB em vários países sugere claramente que sua ocorrência não está restrita a uma região geográfica (BUSCHMANN et al., 2006). ...
... Para muitos cientistas, a hipótese mais aceitável para a origem das EEB atípicas é a forma espontânea, podendo refletir um processo natural de envelhecimento e, talvez, tenha algumas características em comum com outras doenças EET (SEUBERLICH et al., 2010). Apesar dessas afirmações sobre a origem das EEB atípicas, alguns autores consideram prematuro atribuir a essas doenças uma origem espontânea, até que se tenham mais estudos sobre as formas de transmissão (SEUBERLICH et al., 2010). ...
Bovine spongiform encephalopathy (BSE), caused by an infectious prion, emerged in the 1980s in Europe as a new disease in cattle and, since then, several actions are being taken for its prevention and control. Restricting the feeding of ruminants with animal by-products and the removal and destruction of specific risk materials (SRM) for the condition of carcasses in slaughterhouses have been proven effective to control the disease, in addition to the reduction of human exposure to the agent, as this is an important zoonosis. However, in 2004 the first atypical cases of BSE were diagnosed, in which the causative agents showed different molecular weights in Western blot (WB), compared to the classical form of the agent. In addition to the molecular differences, clinical presentations proved to be differentiated in atypical forms, affecting mainly cattle older than eight years. Because it is a new form of the disease, many studies are being conducted to elucidate the pathogenesis, epidemiology and zoonotic potential of atypical BSE. The aim of this study was to review the main aspects of atypical BSE emphasizing its etiology, epidemiology, clinical signs, diagnosis and control and prevention measures.
... Since its introduction in 2001, systematic EU-wide active surveillance for TSE in cattle and small ruminants [EU reg 999/2001] has resulted in the detection of two additional forms of BSE in cattle, commonly referred to collectively as "atypical", that affected mainly cattle eight years of age or older (for reviews see [15,16]). These cases were characterised as different from C-BSE, and designated H-BSE and L-BSE (also referred to as bovine amyloidotic spongiform encephalopathy (BASE) [17]), based on molecular features of the disease-associated form (PrP Sc ) of the host PrP, or prion protein, which is the marker recognised by all current surveillance tests [18,19]. ...
Apart from prion protein genotype, the factors determining the host range and susceptiblity for specific transmissible spongiform encephalopathy agents remain unclear. It is known that bovine atypical L-BSE can transmit to a range of species including primates and humanised transgenic mice. It is important, therefore, that there is as broad an understanding as possible of how such isolates might present in food animal species and how robust they are on inter- and intra-species transmission to inform surveillance sytems and risk assessments. This paper demonstrates that L-BSE can be intracerebrally transmitted to sheep of several genotypes, with the exception of ARR/ARR animals. Positive animals mostly present with a cataplectic form of disease characterized by collapsing episodes and reduced muscle tone. PrP accumulation is confined to the nervous system, with the exception of one animal with lymphoreticular involvement. In Western blot there was maintenance of the low molecular mass and glycoform profile associated with L-BSE, irrespective of ovine host genotype, but there was a substantially higher N-terminal antibody signal relative to the core-specific antibody, which is similar to the ratio associated with classical scrapie. The disease phenotype was maintained on experimental subpassage, but with a shortened survival time indicative of an original species barrier and subsequent adaptation. Passive surveillance approaches would be unlikely to identify such cases as TSE suspects, but current statutory active screening methods would be capable of detecting such cases and classifying them as unusual and requiring further investigation if they were to occur in the field.
Electronic supplementary material
The online version of this article (doi:10.1186/s13567-016-0394-1) contains supplementary material, which is available to authorized users.
