The U.S. Department of Agriculture announced a case of scrapie was detected in a sheep in Oregon on Friday. This is the first case of scrapie found in the U.S. in more than five years.
The USDA Animal and Plant Health Inspection Service confirmed classical scrapie in a sheep slaughtered at a facility in Oregon. It was not immediately clear when the case was discovered.
In a July 31 press release, the USDA said final diagnostic results and genotype analysis were completed by the National Veterinary Services Laboratories, with confirmatory testing indicating classical scrapie.
Scrapie is a fatal, degenerative disease that affects the central nervous system of sheep and goats. It’s believed to be caused by an abnormal protein, or prion.
Prior to this confirmation, the last case of classical scrapie was detected in a sheep sampled at slaughter in January 2021. This sheep was from a flock in Wisconsin and was attributed the flock of origin to Arkansas; it was not completely traceable due to lack of identification to flock of origin, according to the USDA.
The United States was positioned to meet World Organization of Animal Health’s 7‑year benchmark for self‑declared scrapie freedom in January 2028. This confirmed detection could reset that timeline and may push the earliest possible date for national scrapie‑free status to approximately 2033.
Scrapie is hard to detect as it can take 2 to 5 years for an animal to show signs of disease, and current diagnostic tests require brain or lymphoid tissue. Animals typically live 1 to 6 months after they begin to show signs, but death is inevitable.
Prions are also difficult to decontaminate as they are resistant to most disinfectants as well as heat and radiation treatment.
Scrapie is likely spread from mother to offspring or to other lambs or flock members through contact with afterbirth or possibly milk/colostrum.
APHIS and state animal health officials have initiated an epidemiological investigation to determine the flock of origin, but the affected animal did not have ear tags.
To support the investigation, NVSL will conduct tissue‑matching and parentage testing on the affected sheep and two additional animals from the same accession.
APHIS said it expects minimal impact on trade. Most countries restrict live animal exports only from affected flocks or premises, and products such as wool remain unaffected.
More information about scrapie and APHIS’ eradication program is available at www.aphis.usda.gov.
