|Langeveld, Jan p.|
|Baron, Thierry g.|
Submitted to: Journal of Veterinary Diagnostic Investigation
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/15/2007
Publication Date: 1/1/2008
Citation: Gavier-Widen, D., Noremark, M., Langeveld, J.P., Stack, M., Biacabe, A.B., Vulin, J., Chaplin, M., Richt, J.A., Jacobs, J., Acin, C., Monleon, E., Renstrom, L., Klingeborn, B., Baron, T.G. 2008. Bovine spongiform encephalopathy in Sweden: an H-type variant. Journal of Veterinary Diagnostic Investigation. 20(1):2-10. Interpretive Summary: Transmissible spongiform encephalopathies (TSE) are infectious neurodegenerative diseases. Bovine spongiform encephalopathy (BSE) is a TSE primarily of cattle but there is strong evidence that BSE has crossed the species barrier infecting humans and several species of animals. BSE was first identified in the United Kingdom (UK) in 1986 and its human form, variant Creutzfeldt-Jakob (vCJD) in 1996. This manuscript reports the detection of the BSE agent in a 12-year-old cow in Sweden. The Swedish case is characterized as an atypical form of BSE representing the H-type. Several features of this case were different from classical BSE.
Technical Abstract: Bovine spongiform encephalopathy (BSE) had never been detected in Sweden until 2006, when the active surveillance identified a case in a 12-year-old cow. The case was an unusual form since several molecular features of the protease-resistant prion protein (PrP**res) were different from classical BSE. The differences included higher susceptibility for proteinase K, higher molecular weight of the PrP**res bands, affinity to the N-terminus specific antibodies 12B2 and P4 and peculiar banding pattern with antibody SAF84 showing an additional band at 14 kDa position. The molecular characteristics were in accordance to previous descriptions of H-type BSE. This report shows that a range of Western blot techniques and antibodies can be applied to confirm H-type BSE and further describes that the ratio of the amounts of PrP**res#1 and PrP**res#2, after deglycosylation, depends on the antibody used during processing. Immunohistochemistry on sections of medulla at the level of the obex applying antibodies with epitopes covering a broad range of the PrP sequence showed accumulation of disease-specific PrP (PrP**d) in the grey matter. Fine punctate deposition in the neuropil was the most predominant type and was more severe in BSE target nuclei. The types of PrP**d deposition are described in comparison with classical BSE. PrP-gene sequencing showed six copy octarepeat alleles and no abnormalities. It is postulated that the disease had a spontaneous origin, rather than been acquired in the BSE epidemic.