Classical scrapie has been detected in a sheep slaughtered in a facility in Oregon, the US Department of Agriculture’s (USDA) Animal and Plant Health Inspection Service (APHIS) has confirmed.

The case is the first of its kind in five years and the World Organisation for Animal Health (WOAH) has been notified.

Classical scrapie is a fatal, degenerative prion disease of sheep and goats.

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Scrapie-free status

The United States was positioned to meet WOAH’s seven-year benchmark for self-declared scrapie freedom in January 2028.

However, the confirmed detection could reset that timeline and may push the earliest possible date for national scrapie-free status to 2033.

An epidemiological investigation to determine the flock of origin has been initiated by APHIS and state animal health officials.

As the affected animal did not have an ear tag, traceability may be limited, highlighting the critical importance of strong animal identification practices.

To support the investigation, tissue matching and parentage testing will be conducted on the affected sheep and two additional animals from the same accession.

Trade

As most countries restrict live animal exports only from affected flocks or premises – and products such as wool remain unaffected – minimal impact on trade is expected, according to APHIS.

Producers are encouraged to reinforce key practices that have advanced scrapie eradication efforts nationwide, such as:

  • Strict compliance with ear tagging and traceability requirements to ensure exposed animals can be accurately tracked.
  • Robust surveillance participation, including submission of clinical suspects and routine monitoring.
  • Use of genetically resistant breeding stock, which significantly reduces disease susceptibility and depopulation needs.