Issue |
Vet. Res.
Volume 40, Number 6, November-December 2009
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Number of page(s) | 13 | |
DOI | https://doi.org/10.1051/vetres/2009048 | |
Published online | 18 August 2009 | |
How to cite this article | Vet. Res. (2009) 40:65 |
DOI: 10.1051/vetres/2009048
High prevalence of scrapie in a dairy goat herd: tissue distribution of disease-associated PrP and effect of PRNP genotype and age
Lorenzo González1, Stuart Martin1, Sílvia Sisó1, Timm Konold2, Angel Ortiz-Peláez2, Laura Phelan2, Wilfred Goldmann3, Paula Stewart3, Ginny Saunders2, Otto Windl2, Martin Jeffrey1, Stephen A.C. Hawkins2, Michael Dawson2 and James Hope11 Veterinary Laboratories Agency (VLA-Lasswade), Pentlands Science Park, Penicuik, Midlothian EH26 0PZ, United Kingdom
2 VLA-Weybridge, Addlestone, Surrey KT15 3NB, United Kingdom
3 Roslin Institute Neuropathogenesis Division, Roslin, Midlothian EH25 9PS, United Kingdom
Received 8 April 2009; accepted 14 August 2009; published online 18 August 2009
Abstract - Following a severe outbreak of clinical scrapie in 2006–2007, a
large dairy goat herd was culled
and 200 animals were selected for post-mortem examinations in order to
ascertain the prevalence of infection,
the effect of age, breed and PRNP genotype on the susceptibility to scrapie,
the tissue distribution of diseaseassociated
PrP (PrP), and the comparative efficiency of different diagnostic methods.
As determined by immunohistochemical (IHC) examinations with Bar224 PrP antibody, the
prevalence of preclinical infection
was very high (72/200; 36.0%), with most infected animals being positive
for PrP
in lymphoreticular system
(LRS) tissues (68/72; 94.4%) compared to those that were positive in
brain samples (38/72; 52.8%). The
retropharyngeal lymph node and the palatine tonsil showed the highest
frequency of PrP
accumulation (87.3%
and 84.5%, respectively), while the recto-anal mucosa-associated lymphoid
tissue (RAMALT) was positive in
only 30 (41.7%) of the infected goats. However, the efficiency of rectal
and palatine tonsil biopsies taken
shortly before necropsy was similar. The probability of brain and RAMALT
being positive directly
correlated with the spread of PrP
within the LRS. The prevalence of
infection was influenced by PRNP
genetics at codon 142 and by the age of the goats: methionine carriers older
than 60 months showed a much
lower prevalence of infection (12/78; 15.4%) than those younger than 60 months (20/42; 47.6%); these last
showed prevalence values similar to isoleucine homozygotes of any age
(40/80; 50.0%). Two of seven goats
with definite signs of scrapie were negative for PrP
in brain but positive
in LRS tissues, and one goat showed
biochemical and IHC features of PrP
different from all other infected
goats. The results of this study have
implications for surveillance and control policies for scrapie in goats.
Key words: scrapie / goat / prion disease / transmissible spongiform encephalopathy
Corresponding author: l.gonzalez@vla.defra.gsi.gov.uk
© INRA, EDP Sciences 2009