NR AWSZ
AU Gonzalez,L.; Dagleish,M.P.; Bellworthy,S.J.; Hawkins,S.A.C.; Martin,S.; Siso,S.; Jackman,R.; Terry,L.; Horton,R.; Dexter,G.; Steele,P.; Reid,H.W.; Jeffrey,M.J.
TI Diagnosis of clinical and preclinical sheep scrapie in rectal biopsy specimens
QU European Society of Veterinary Pathology, 24th Meeting, Edinburgh, Scotland, 30.8.-2.9.2006, Poster 114: 213
IA http://www.esvp.eu/ESVP_meetings/Proceedings_2006.pdf
PT Konferenz-Poster
AB
The current approach for sheep scrapie surveillance is based on laboratory examinations for disease-associated prion protein (PrPd) on samples of central nervous system (CNS). We have conducted a large survey of immunohistochemical (IHC) detection of PrPd in CNS, lymphoreticular system (LRS) tissue and rectal mucosa samples of scrapie-exposed sheep with and without signs of clinical disease. Scrapie confirmed cases included 244 with clinical disease, of which 241 were positive in the rectal mucosa (97.1%) and 121 apparently healthy sheep, 104 of which were RAMALT positive (86%). Preclinical detection of PrPd was similarly efficient in the other LRS tissues examined (86.4-91.5%) and less so in the CNS (77.7%). The stage of infection, therefore, affected the probability of a positive result in the rectal mucosa, while the breed, PrP genotype, age and sex had little or no independent effect. Two ELISA assays were initially assessed on rectal mucosa samples and one of them was selected for further optimisation; once completed, the sensitivity of this rapid test reached 94% of that of IHC.
A total of 328 biopsy specimens of rectal mucosa were examined by IHC, while another 46 samples from sheep with previous IHC positive results were examined by ELISA. Positive IHC results were obtained in both naturally and experimentally infected sheep, with similar efficiency regardless of the route of inoculation. The efficiency of rectal mucosa biopsies for the detection of abnormal PrP was totally comparable to that of the palatine tonsil, and found that ELISA testing of biopsy samples provided a high diagnostic sensitivity.
We conclude that rectal mucosa samples taken at post-mortem could be considered as an alternative to CNS samples in active and passive surveillance programmes, and that rectal mucosa biopsies are a promising approach for the preclinical diagnosis of scrapie in the live animal.
AD Lorenzo González (l.gonzalez@vla.defra.gsi.gov.uk), Mark P. Dagleish, Sue J. Bellworthy, Steve A.C. Hawkins, Stuart Martin, Sílvia Sisó (s.siso@vla.defra.gsi.gov.uk), Roy Jackman, Linda Terry, Robert Horton, Glenda Dexter, Philip Steele, Hugh W. Reid, Martin J. Jeffrey (m.jeffrey@vla.maff.gov.uk), Veterinary Laboratories Agency (VLA-Lasswade), UK
SP englisch
PO UK