Transmission of atypical BSE: a possible origin of Classical BSE in cattle

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Title: Transmission of atypical BSE: a possible origin of Classical BSE in cattle

Authors: Sandor Dudas1, Samuel James Sharpe1, Kristina Santiago-Mateo1, Stefanie Czub1, Waqas Tahir1,2, * Affiliation: 1National and WOAH reference Laboratory for Bovine Spongiform Encephalopathy, Canadian Food inspection Agency, Lethbridge Laboratory, Lethbridge, Canada. 2Department of Biological Sciences, University of Lethbridge, Lethbridge, Alberta, Canada. *Corresponding and Presenting Author: [email protected]

Background: Bovine spongiform encephalopathy (BSE) is a fatal neurodegenerative disease of cattle and is categorized into classical and atypical forms. Classical BSE (CBSE) is linked to the consumption of BSE contaminated feed whereas atypical BSE is considered to be spontaneous in origin. The potential for oral transmission of atypical BSE is yet to be clearly defined.

Aims: To assess the oral transmissibility of atypical BSE (H and L type) in cattle. Should transmission be successful, determine the biochemical characteristics and distribution of PrPSc in the challenge cattle.

Material and Methods: For oral transmission, calves were fed with 100 g of either H (n=3) or L BSE (n=3) positive brain material. Two years post challenge, 1 calf from each of the H and L BSE challenge groups exhibited behavioural signs and were euthanized. Various brain regions of both animals were tested by traditional and novel prion detection methods with inconclusive results. To detect infectivity, brain homogenates from these oral challenge animals (P1) were injected intra-cranially (IC) into steer calves. Upon clinical signs of BSE, 3/4 of IC challenged steer calves were euthanized and tested for PrPSc with ELISA, immunohistochemistry and immunoblot.

Results: After 6 years of incubation, 3/4 animals (2/2 steers IC challenged with brain from P1 L-BSE oral challenge and 1/2 steer IC challenged with brain from P1 H-BSE oral challenge) developed clinical disease. Analysis of these animals revealed high levels of PrPSc in their brains, having biochemical properties similar to that of PrPSc in C-BSE.

Conclusion: These results demonstrate the oral transmission potential of atypical BSE in cattle. Surprisingly, regardless of which atypical type of BSE was used for P1 oral challenge, PrPSc in the P2 animals acquired biochemical characteristics similar to that of PrPSc in C-BSE, suggesting atypical BSE as a possible origin of C-BSE in UK.

Presentation Type: Oral Presentation Funded by: CFIA, Health Canada, Alberta Livestock and Meat Agency, Alberta Prion Research Institute

Grant Number: ALMA/APRI: 201400006, HC 414250

Acknowledgement: TSE unit NCAD, Lethbridge (Jianmin Yang, Sarah Bogart, Rachana Muley, Yuanmu Fang, Keri Colwell, Renee Anderson, John Gray, Rakhi Katoch) (CFIA, Canada), Dr. Catherine Graham (NSDA, Canada), Dr. Michel Levy (UCVM, Canada), Dr. Martin Groschup (FLI, Germany), Dr. Christine Fast (FLI, Germany), Dr. Bob Hills (Health Canada, Canada) Theme: Animal prion diseases

"After 6 years of incubation, 3/4 animals (2/2 steers IC challenged with brain from P1 L-BSE oral challenge and 1/2 steer IC challenged with brain from P1 H-BSE oral challenge) developed clinical disease. Analysis of these animals revealed high levels of PrPSc in their brains, having biochemical properties similar to that of PrPSc in C-BSE. "
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PRION 2023 CONTINUED; https://prion2023.org/wp-content/uploads/2023/10/Meeting-book-final-version2.pdf

Molecular phenotype shift after passage of low-type bovine spongiform encephalopathy (L-BSE).

Zoe J. Lambert, M. Heather West Greenlee, Jifeng Bian, Justin J. Greenlee Ames, USA

Aims: The purpose of this study is to compare the molecular phenotypes of L-BSE in wild type cattle and cattle with the E211K polymorphism to samples of other cattle TSEs, such as classical BSE (C-BSE), hightype BSE (H-BSE), and transmissible mink encephalopathy (TME).

Materials and Methods: Two wild type cattle (EE211 PRNP) and one steer with the E211K polymorphism (EK211) were intracranially inoculated with 1 mL of brain homogenate that originated from a 2005 French L-BSE case. Multiple assays were used to compare and differentiate tissues, including enzyme immunoassay, western blot (Sha31, 12B2, SAF84), stability (Sha31), and immunohistochemistry (F99/97).

Results: Approximately 16.6 months post-inoculation, Steer 6 (EK211 L-BSE) developed neurologic signs, including agitation, difficulty eating accompanied by weight loss, head tremor, ataxia, and fasciculations in the forelimbs, and was necropsied. Enzyme immunoassays demonstrated misfolded prion protein in the brainstem (4.0 O.D) but not in peripheral tissues, such as the retropharyngeal lymph node and palatine tonsil. When compared by western blot, the molecular phenotype of the brainstem of Steer 6 (EK211 L-BSE) is higher than that of wildtype cattle inoculated with L-BSE, requiring careful differentiation from C-BSE. Ongoing mouse studies in bovinized mice (K211 and TgBov) will provide data to compare to all other BSE strains available, including L-BSE, C-BSE, H-BSE, E211K H-BSE, and TME.

Conclusions: Further study of L-BSE in EK211 cattle with a higher molecular phenotype in the brainstem may give more insight into the origin of C-BSE.

Funded by: This research was funded in its entirety by congressionally appropriated funds to the United States Department of Agriculture, Agricultural Research Service. The funders of the work did not influence study design, data collection and analysis, decision to publish, or preparation of the manuscript. This research was supported in part by an appointment to the Agricultural Research Service (ARS) Research Participation Program administered by the Oak Ridge Institute for Science and Education (ORISE) through an interagency agreement between the U.S. Department of Energy (DOE) and the U.S. Department of Agriculture (USDA). ORISE is managed by ORAU under DOE contract number DE-SC0014664. All opinions expressed in this paper are the author's and do not necessarily reflect the policies and views of USDA, ARS, DOE, or ORAU/ORISE.

Grant number: DOE contract number DE-SC0014664 Acknowledgements: NA Theme: Animal prion diseases
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PRION 2023 CONTINUED; https://prion2023.org/wp-content/uploads/2023/10/Meeting-book-final-version2.pdf
 
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