title: Chronic wasting disease in bank voles: characterisation of the shortest incubation time model for prion diseases.
abstract: In order to assess the susceptibility of bank voles to chronic wasting disease (CWD), we inoculated voles carrying isoleucine or methionine at codon 109 (Bv109I and Bv109M, respectively) with CWD isolates from elk, mule deer and white-tailed deer. Efficient transmission rate (100%) was observed with mean survival times ranging from 156 to 281 days post inoculation. Subsequent passages in Bv109I allowed us to isolate from all CWD sources the same vole-adapted CWD strain (Bv(109I)CWD), typified by unprecedented short incubation times of 25-28 days and survival times of ∼35 days. Neuropathological and molecular characterisation of Bv(109I)CWD showed that the classical features of mammalian prion diseases were all recapitulated in less than one month after intracerebral inoculation. Bv(109I)CWD was characterised by a mild and discrete distribution of spongiosis and relatively low levels of protease-resistant PrP(Sc) (PrP(res)) in the same brain regions. Despite the low PrP(res) levels and the short time lapse available for its accumulation, end-point titration revealed that brains from terminally-ill voles contained up to 10(8,4) i.c. ID50 infectious units per gram. Bv(109I)CWD was efficiently replicated by protein misfolding cyclic amplification (PMCA) and the infectivity faithfully generated in vitro, as demonstrated by the preservation of the peculiar Bv(109I)CWD strain features on re-isolation in Bv109I. Overall, we provide evidence that the same CWD strain was isolated in Bv109I from the three-cervid species. Bv(109I)CWD showed unique characteristics of "virulence", low PrP(res) accumulation and high infectivity, thus providing exceptional opportunities to improve basic knowledge of the relationship between PrP(Sc), neurodegeneration and infectivity.
authors.affiliation: Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità, Rome, Italy. michele.dibari@iss.it
authors.forename: Michele Angelo
authors.initials: MA
authors.lastname: Di Bari
authors.forename: Romolo
authors.initials: R
authors.lastname: Nonno
authors.forename: Joaquín
authors.initials: J
authors.lastname: Castilla
authors.forename: Claudia
authors.initials: C
authors.lastname: D'Agostino
authors.forename: Laura
authors.initials: L
authors.lastname: Pirisinu
authors.forename: Geraldina
authors.initials: G
authors.lastname: Riccardi
authors.forename: Michela
authors.initials: M
authors.lastname: Conte
authors.forename: Juergen
authors.initials: J
authors.lastname: Richt
authors.forename: Robert
authors.initials: R
authors.lastname: Kunkle
authors.forename: Jan
authors.initials: J
authors.lastname: Langeveld
authors.forename: Gabriele
authors.initials: G
authors.lastname: Vaccari
authors.forename: Umberto
authors.initials: U
authors.lastname: Agrimi
mesh_terms: D000818:Animals; D003411:Arvicolinae; D001921:Brain / Q000473:pathology; D011328:Prions; D017510:Protein Folding; D034081:Wasting Disease, Chronic / Q000378:metabolism* / Q000473:pathology / Q000635:transmission*
chemical_list: D011328:Prions