Experimental transmission of atypical scrapie to sheep.
BACKGROUND
Active surveillance for transmissible spongiform encephalopathies in small ruminants has been an EU regulatory requirement since 2002. A number of European countries have subsequently reported cases of atypical scrapie, similar to previously published cases from Norway, which have pathological and molecular features distinct from classical scrapie. Most cases have occurred singly in flocks, associated with genotypes considered to be more resistant to classical disease. Experimental transmissibility of such isolates has been reported in certain ovinised transgenic mice, but has not previously been reported in the natural host. Information on the transmissibility of this agent is vital to ensuring that disease control measures are effective and proportionate.


RESULTS
This report presents the successful experimental transmission, in 378 days, of atypical scrapie to a recipient sheep of homologous genotype with preservation of the pathological and molecular characteristics of the donor. This isolate also transmitted to ovinised transgenic mice (Tg338) with a murine phenotype indistinguishable from that of Nor 98.


CONCLUSIONS
This result strengthens the opinion that these cases result from a distinct strain of scrapie agent, which is potentially transmissible in the natural host under field conditions.
Simmons
Marion M
MM
Department of Pathology, Veterinary Laboratories Agency - Weybridge, Woodham Lane, New Haw, Addlestone, Surrey KT15 3NB, UK. m.m.simmons@vla.defra.gsi.gov.uk
Konold
Timm
T
Simmons
Hugh A
HA
Spencer
Yvonne I
YI
Lockey
Richard
R
Spiropoulos
John
J
Everitt
Sharon
S
Clifford
Derek
D
D000818:Animals; D015153:Blotting, Western / Q000662:veterinary; D001921:Brain / Q000378:metabolism* / Q000473:pathology; D004196:Disease Outbreaks / Q000662:veterinary*; D005060:Europe / Q000453:epidemiology; D005062:European Union; D020022:Genetic Predisposition to Disease; D005838:Genotype; D007150:Immunohistochemistry / Q000662:veterinary; D018620:PrPSc Proteins / Q000008:administration & dosage / Q000378:metabolism*; D012608:Scrapie / Q000453:epidemiology / Q000235:genetics / Q000378:metabolism / Q000635:transmission*; D012756:Sheep
D018620:PrPSc Proteins