title: The pathological and molecular but not clinical phenotypes are maintained after second passage of experimental atypical bovine spongiform encephalopathy in cattle.
abstract: BACKGROUND
  Atypical bovine spongiform encephalopathies (BSEs), classified as H-type and L-type BSE based on the Western immunoblot profiles, are naturally occurring diseases in cattle, which are phenotypically different to classical BSE. Transmission studies in cattle using the intracerebral route resulted in disease where the phenotypes were maintained irrespective of BSE type but clinically affected cattle with a shorter survival time displayed a nervous form whereas cattle with a longer survival time displayed a dull form. A second transmission study is reported here where four cattle were intracerebrally inoculated with brain tissue from experimentally infected cattle presenting with either the nervous or dull form of H- or L-type BSE to determine whether the phenotype is maintained.
  
  
  RESULTS
  The four inoculated cattle were culled at 16.5-19.5 months post inoculation after presenting with difficulty getting up, a positive scratch response (all) and dullness (three cattle), which was not observed in two non-inoculated control cattle, each housed with either group of inoculated cattle. Only the inoculated cattle had detectable prion protein in the brain based on immunohistochemical examination, and the Western immunoblot profile was consistent with the H-type or L-type BSE of the respective donor cattle.
  
  
  CONCLUSIONS
  Second passage of H-type and L-type BSE in cattle produced a TSE where the majority of cattle displayed the dull form regardless of clinical disease form of the donor cattle. The pathological and molecular phenotypes of H- and L-type BSE were maintained.
authors.affiliation: Animal Sciences Unit, Animal Health and Veterinary Laboratories Agency, New Haw, Addlestone, KT15 3NB, UK. timm.konold@ahvla.gsi.gov.uk.
authors.forename: Timm
authors.initials: T
authors.lastname: Konold
authors.affiliation: Pathology Department, Animal Health and Veterinary Laboratories Agency, New Haw, Addlestone, KT15 3NB, UK. laura.konold@ahvla.gsi.gov.uk.
authors.forename: Laura J
authors.initials: LJ
authors.lastname: Phelan
authors.affiliation: Animal Sciences Unit, Animal Health and Veterinary Laboratories Agency, New Haw, Addlestone, KT15 3NB, UK. derek.clifford@ahvla.gsi.gov.uk.
authors.forename: Derek
authors.initials: D
authors.lastname: Clifford
authors.affiliation: Prion Unit, Virology Department, Animal Health and Veterinary Laboratories Agency, New Haw, Addlestone, KT15 3NB, UK. melanie.chaplin@ahvla.gsi.gov.uk.
authors.forename: Melanie J
authors.initials: MJ
authors.lastname: Chaplin
authors.affiliation: Central Sequencing Unit, Animal Health and Veterinary Laboratories Agency, New Haw, Addlestone, KT15 3NB, UK. saira.cawthraw@ahvla.gsi.gov.uk.
authors.forename: Saira
authors.initials: S
authors.lastname: Cawthraw
authors.affiliation: Prion Unit, Virology Department, Animal Health and Veterinary Laboratories Agency, New Haw, Addlestone, KT15 3NB, UK. mick.stack@ahvla.gsi.gov.uk.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Stack
authors.affiliation: Pathology Department, Animal Health and Veterinary Laboratories Agency, New Haw, Addlestone, KT15 3NB, UK. marion.simmons@ahvla.gsi.gov.uk.
authors.forename: Marion M
authors.initials: MM
authors.lastname: Simmons
mesh_terms: D000818:Animals; D015153:Blotting, Western / Q000662:veterinary; D001921:Brain / Q000473:pathology; D002417:Cattle; D016643:Encephalopathy, Bovine Spongiform / Q000175:diagnosis / Q000378:metabolism / Q000401:mortality / Q000473:pathology* / Q000635:transmission; D005260:Female; D008297:Male; D010641:Phenotype; D016019:Survival Analysis