title: No H- and L-type cases in Belgium in cattle diagnosed with bovine spongiform encephalopathy (1999-2008) aging seven years and older.
abstract: BACKGROUND
  The bovine spongiform encephalopathy (BSE) epidemic presented homogeneity of the phenotype. This classical BSE (called C-type) was probably due to the contamination of the food chain by a single prion strain. However, due to the active surveillance and better techniques, two rare variants of BSE have been recently reported in different continents without a clear correlation to the BSE epidemic. These emerging types behave as different strains of BSE and were named H-type and L-type according to the high and low molecular mass of the unglycosylated fragment of their proteinase K resistant prion protein (PrPres). In these types, the proportion of the un-, mono- and di-glycosylated fragments of PrP (glycoprofile) is also atypical and represents an effective diagnostic parameter. This study evaluated the presence of such types in bovine of 7 years and older in Belgium.
  
  
  RESULTS
  The Belgian BSE archive contained 41 bovines of at least 7 years of age. The biochemical features of their PrPres were analyzed by Western blot with five antibodies recognising different regions of PrPres, from N- to C-terminus: 12B2, 9A2, Sha31, SAF84 and 94B4. All antibodies clearly detected PrPres except 12B2 antibody, which is specific for N-terminal region 101-105, a PrP region that is only retained in H-types. The glycoprofiles did correspond to that of C-type (with more than 55% of diglycosylated PrPres using antibody 94B4). Therefore, all cases have the features of C-type BSE.
  
  
  CONCLUSIONS
  This study supports that, among the BSE cases of 7 years and older identified in Belgium, none was apparently of the H- or L- type. This is consistent with the very rare occurrence of atypical BSE and the restricted dimension of Belgium. These results shed some light on the worldwide prevalence of atypical BSE.
authors.affiliation: Veterinary and Agrochemical Research Centre, Brussels, Belgium. aldob@var.fgov.be
authors.forename: Alexandre
authors.initials: A
authors.lastname: Dobly
authors.forename: Jan
authors.initials: J
authors.lastname: Langeveld
authors.forename: Lucien
authors.initials: L
authors.lastname: van Keulen
authors.forename: Caroline
authors.initials: C
authors.lastname: Rodeghiero
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Durand
authors.forename: Riet
authors.initials: R
authors.lastname: Geeroms
authors.forename: Patrick
authors.initials: P
authors.lastname: Van Muylem
authors.forename: Jessica
authors.initials: J
authors.lastname: De Sloovere
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Vanopdenbosch
authors.forename: Stefan
authors.initials: S
authors.lastname: Roels
mesh_terms: D000375:Aging; D000818:Animals; D001530:Belgium / Q000453:epidemiology; D002417:Cattle; D016643:Encephalopathy, Bovine Spongiform / Q000145:classification / Q000453:epidemiology* / Q000378:metabolism; D015995:Prevalence