title: Experimental H-type and L-type bovine spongiform encephalopathy in cattle: observation of two clinical syndromes and diagnostic challenges.
abstract: BACKGROUND
  The majority of atypical bovine spongiform encephalopathy (BSE) cases so far identified worldwide have been detected by active surveillance. Consequently the volume and quality of material available for detailed characterisation is very limiting. Here we report on a small transmission study of both atypical forms, H- and L-type BSE, in cattle to provide tissue for test evaluation and research, and to generate clinical, molecular and pathological data in a standardised way to enable more robust comparison of the two variants with particular reference to those aspects most relevant to case ascertainment and confirmatory diagnosis within existing regulated surveillance programmes.
  
  
  RESULTS
  Two groups of four cattle, intracerebrally inoculated with L-type or H-type BSE, all presented with a nervous disease form with some similarities to classical BSE, which progressed to a more dull form in one animal from each group. Difficulty rising was a consistent feature of both disease forms and not seen in two BSE-free, non-inoculated cattle that served as controls. The pathology and molecular characteristics were distinct from classical BSE, and broadly consistent with published data, but with some variation in the pathological characteristics. Both atypical BSE types were readily detectable as BSE by current confirmatory methods using the medulla brain region at the obex, but making a clear diagnostic distinction between the forms was not consistently straightforward in this brain region. Cerebellum proved a more reliable sample for discrimination when using immunohistochemistry.
  
  
  CONCLUSIONS
  The prominent feature of difficulty rising in atypical BSE cases may explain the detection of naturally occurring cases in emergency slaughter cattle and fallen stock. Current confirmatory diagnostic methods are effective for the detection of such atypical cases, but consistently and correctly identifying the variant forms may require modifications to the sampling regimes and methods that are currently in use.
authors.affiliation: TSE Department, Animal Health and Veterinary Laboratories Agency Weybridge, New Haw, Addlestone, UK. timm.konold@ahvla.gsi.gov.uk
authors.forename: Timm
authors.initials: T
authors.lastname: Konold
authors.forename: Gemma E
authors.initials: GE
authors.lastname: Bone
authors.forename: Derek
authors.initials: D
authors.lastname: Clifford
authors.forename: Melanie J
authors.initials: MJ
authors.lastname: Chaplin
authors.forename: Saira
authors.initials: S
authors.lastname: Cawthraw
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Stack
authors.forename: Marion M
authors.initials: MM
authors.lastname: Simmons
mesh_terms: D020155:3-Hydroxybutyric Acid / Q000097:blood; D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D001219:Aspartate Aminotransferases / Q000097:blood; D001522:Behavior, Animal / Q000502:physiology; D001663:Bilirubin / Q000097:blood; D015153:Blotting, Western / Q000662:veterinary; D001921:Brain / Q000473:pathology*; D002417:Cattle; D004573:Electrolytes / Q000097:blood; D016643:Encephalopathy, Bovine Spongiform / Q000097:blood / Q000235:genetics / Q000473:pathology*; D005340:Fibrinogen / Q000032:analysis; D005916:Globulins / Q000032:analysis; D005979:Glutathione Peroxidase / Q000097:blood; D006242:Haptoglobins / Q000032:analysis; D007150:Immunohistochemistry / Q000662:veterinary; D008297:Male; D012709:Serum Albumin / Q000032:analysis; D014508:Urea / Q000097:blood; D014810:Vitamin E / Q000097:blood
chemical_list: D004573:Electrolytes; D005916:Globulins; D006242:Haptoglobins; D012709:Serum Albumin; D014810:Vitamin E; D014508:Urea; D005340:Fibrinogen; D005979:Glutathione Peroxidase; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D001663:Bilirubin; D020155:3-Hydroxybutyric Acid