Improving Clinical Diagnosis of Transmissible Spongiform Encephalopathies in Sheep: Which Signs Are Important?

Scrapie is a notifiable transmissible spongiform encephalopathy (TSE) in sheep that relies on clinical examinations for reporting suspects. A short examination protocol was used in 1002 sheep to define clinical markers suggestive of scrapie. Sheep were naturally or experimentally exposed to a classi...

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Main Authors: Timm Konold, Laura J. Phelan
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Animals
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Online Access:https://www.mdpi.com/2076-2615/15/9/1310
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author Timm Konold
Laura J. Phelan
author_facet Timm Konold
Laura J. Phelan
author_sort Timm Konold
collection DOAJ
description Scrapie is a notifiable transmissible spongiform encephalopathy (TSE) in sheep that relies on clinical examinations for reporting suspects. A short examination protocol was used in 1002 sheep to define clinical markers suggestive of scrapie. Sheep were naturally or experimentally exposed to a classical, atypical scrapie or bovine spongiform encephalopathy agent; 312 were positive for a transmissible spongiform encephalopathy (TSE) by brain examination and included non-exposed controls. Assessed signs were posture, behaviour, menace, scratch and blindfolding response, wool loss and skin changes, body condition, incoordination and tremor. First, the combined occurrence of two or more clinical signs was compared between TSE-positive and negative sheep. Second, the importance of clinical markers was determined in a general classification and regression tree model. The main clinical markers to predict TSEs according to the tree model were incoordination and a positive scratch test. Test sensitivities and specificities were 70.8–81.5% and 96.1–93.0%, respectively, and predictive values above 87%. The results suggest that the short clinical protocol, which assesses the presence of certain clinical signs associated with a TSE in sheep and is quick to perform, may be useful to reach a suspect diagnosis in both naturally and experimentally generated TSEs.
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spelling doaj-art-012223fd2d324e6d9ee2270639ac67872025-08-20T02:58:43ZengMDPI AGAnimals2076-26152025-05-01159131010.3390/ani15091310Improving Clinical Diagnosis of Transmissible Spongiform Encephalopathies in Sheep: Which Signs Are Important?Timm Konold0Laura J. Phelan1Department of Pathology & Animal Sciences, Animal & Plant Health Agency Weybridge, Addlestone KT15 3NB, UKDepartment of Pathology & Animal Sciences, Animal & Plant Health Agency Weybridge, Addlestone KT15 3NB, UKScrapie is a notifiable transmissible spongiform encephalopathy (TSE) in sheep that relies on clinical examinations for reporting suspects. A short examination protocol was used in 1002 sheep to define clinical markers suggestive of scrapie. Sheep were naturally or experimentally exposed to a classical, atypical scrapie or bovine spongiform encephalopathy agent; 312 were positive for a transmissible spongiform encephalopathy (TSE) by brain examination and included non-exposed controls. Assessed signs were posture, behaviour, menace, scratch and blindfolding response, wool loss and skin changes, body condition, incoordination and tremor. First, the combined occurrence of two or more clinical signs was compared between TSE-positive and negative sheep. Second, the importance of clinical markers was determined in a general classification and regression tree model. The main clinical markers to predict TSEs according to the tree model were incoordination and a positive scratch test. Test sensitivities and specificities were 70.8–81.5% and 96.1–93.0%, respectively, and predictive values above 87%. The results suggest that the short clinical protocol, which assesses the presence of certain clinical signs associated with a TSE in sheep and is quick to perform, may be useful to reach a suspect diagnosis in both naturally and experimentally generated TSEs.https://www.mdpi.com/2076-2615/15/9/1310scrapietransmissible spongiform encephalopathyprionbovine spongiform encephalopathysheepclinical examination
spellingShingle Timm Konold
Laura J. Phelan
Improving Clinical Diagnosis of Transmissible Spongiform Encephalopathies in Sheep: Which Signs Are Important?
Animals
scrapie
transmissible spongiform encephalopathy
prion
bovine spongiform encephalopathy
sheep
clinical examination
title Improving Clinical Diagnosis of Transmissible Spongiform Encephalopathies in Sheep: Which Signs Are Important?
title_full Improving Clinical Diagnosis of Transmissible Spongiform Encephalopathies in Sheep: Which Signs Are Important?
title_fullStr Improving Clinical Diagnosis of Transmissible Spongiform Encephalopathies in Sheep: Which Signs Are Important?
title_full_unstemmed Improving Clinical Diagnosis of Transmissible Spongiform Encephalopathies in Sheep: Which Signs Are Important?
title_short Improving Clinical Diagnosis of Transmissible Spongiform Encephalopathies in Sheep: Which Signs Are Important?
title_sort improving clinical diagnosis of transmissible spongiform encephalopathies in sheep which signs are important
topic scrapie
transmissible spongiform encephalopathy
prion
bovine spongiform encephalopathy
sheep
clinical examination
url https://www.mdpi.com/2076-2615/15/9/1310
work_keys_str_mv AT timmkonold improvingclinicaldiagnosisoftransmissiblespongiformencephalopathiesinsheepwhichsignsareimportant
AT laurajphelan improvingclinicaldiagnosisoftransmissiblespongiformencephalopathiesinsheepwhichsignsareimportant