Scrapie in Sheep: Prion Disease, Itching, Ataxia, and Reporting Requirements
- See your vet immediately if a sheep has progressive itching, wool loss on both sides of the body, tremors, behavior changes, weakness, or an abnormal hopping or swaying gait.
- Scrapie is a fatal prion disease of the central nervous system. There is no curative treatment or vaccine, and suspected cases have reporting implications in the United States.
- Signs often appear years after infection, most commonly in adult sheep 2 to 5 years old. Once signs begin, affected sheep usually decline over 1 to 6 months.
- Diagnosis may involve flock history, official identification review, rule-outs for other neurologic disease, and USDA-supported testing of live or postmortem tissues through your vet or animal health officials.
What Is Scrapie in Sheep?
Scrapie is a fatal prion disease of sheep that affects the brain and spinal cord. A prion is a misfolded protein that causes normal proteins in the body to fold abnormally too. Over time, that damages nervous tissue and leads to slowly progressive neurologic disease.
This condition belongs to a group called transmissible spongiform encephalopathies. In sheep, classic signs can include intense rubbing or scratching, behavior changes, tremors, poor coordination, weakness, and eventual inability to stand. Not every sheep shows every sign, and some start with only subtle changes.
Scrapie usually has a long incubation period. Many sheep are infected when they are young, but do not look sick until they are adults, often between 2 and 5 years of age. Once clinical signs begin, the disease is progressive and fatal.
Because scrapie is both an animal health and regulatory concern, it is not something to watch at home and hope improves. If you suspect it, involve your vet immediately so the sheep can be evaluated, other causes can be considered, and reporting steps can be handled correctly.
Symptoms of Scrapie in Sheep
- Progressive itching or repeated rubbing
- Ataxia or poor coordination
- Behavior changes
- Tremors
- Weight loss despite normal appetite
- Weakness or difficulty rising
- Increased sensitivity to sound or sudden movement
- Head pressing or star-gazing
See your vet immediately if a sheep has progressive neurologic signs, unexplained intense itching, or chronic weight loss without another clear cause. Scrapie signs overlap with other serious problems, including listeriosis, rabies, meningitis, brain abscesses, parasites, and chronic wasting diseases. A sheep that is down, unable to rise, or showing worsening coordination should be treated as urgent both medically and from a flock-health standpoint.
What Causes Scrapie in Sheep?
Scrapie is caused by an infectious prion, not by bacteria, parasites, or a typical virus. The abnormal prion protein is very resistant in the environment and to many routine disinfection methods. That makes control harder than with many other infectious diseases.
Most transmission is believed to happen around lambing. Infectious prions are shed in high amounts in the placenta, placental fluids, and contaminated lambing areas. Lambs are often infected at or near birth, either from their dam or from the environment. Prions have also been detected in milk and colostrum, and contaminated facilities can remain risky for long periods.
Genetics matter in sheep. Certain PRNP genotypes are associated with greater susceptibility, while others are associated with increased resistance to classical scrapie. Genotyping can help with flock planning, but it does not replace testing, biosecurity, or official disease control steps.
Adult infection can happen, but younger animals appear more vulnerable. Rams can become infected, yet transmission risk is thought to be much lower through breeding than through exposure to infected birth materials and contaminated lambing environments.
How Is Scrapie in Sheep Diagnosed?
Scrapie cannot be confirmed by signs alone. Your vet will start with a history and neurologic exam, then consider other diseases that can look similar. Important clues include the sheep's age, whether signs are slowly progressive, flock history, lambing exposure, official identification, and whether more than one animal has shown compatible signs.
Testing options depend on whether the sheep is alive or has died. Postmortem testing remains the most reliable approach and typically uses brain tissue and sometimes lymphoid tissue examined by approved laboratories. Antemortem testing exists, but sensitivity is lower, so a negative live-animal test does not always rule scrapie out.
In the United States, your vet may work with USDA APHIS and State animal health officials on sample submission, traceability, and reporting. APHIS states that producers, accredited veterinarians, and animal health personnel may submit samples from adult sheep and goats, and the agency may cover approved testing and shipping for eligible submissions.
If a sheep dies after showing chronic weight loss, itching, or neurologic signs, ask your vet whether a necropsy with scrapie testing is appropriate. That step can protect the rest of the flock by helping identify or rule out a reportable disease.
Treatment Options for Scrapie in Sheep
Spectrum of Care means you have options. Here are treatment tiers at different price points.
Budget-Conscious Care
- Immediate isolation of the suspect sheep from lambing areas and close-contact groups
- Prompt exam by your vet to assess welfare and rule out treatable look-alike conditions
- Reporting coordination with State/USDA animal health officials when scrapie is suspected
- USDA-supported sample submission from an eligible dead or euthanized adult sheep
- Basic flock review of animal ID, lambing exposure, and recent deaths
Recommended Standard Treatment
- Full veterinary evaluation with neurologic and body-condition assessment
- Rule-outs for common differentials based on the case, such as listeriosis, parasites, dental disease, or trauma
- Official identification verification and movement-history review
- Antemortem sampling when appropriate, plus postmortem testing if the sheep dies or is euthanized
- Flock-level guidance on exposure management, lambing hygiene, and recordkeeping
Advanced / Critical Care
- Comprehensive flock investigation with your vet and animal health officials
- PRNP genotyping of sheep to guide long-term breeding and cleanup decisions
- Expanded testing of exposed or high-risk animals as directed by officials
- Detailed premises cleaning and disinfection planning for prion risk reduction
- Enrollment or participation review for the Scrapie-Free Flock Certification Program and long-term traceability improvements
Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.
Questions to Ask Your Vet About Scrapie in Sheep
Bring these questions to your vet appointment to get the most out of your visit.
- Do this sheep's signs fit scrapie, or are there other likely causes we should rule out first?
- Does this case need immediate reporting to State or USDA animal health officials?
- Should we do live-animal testing, postmortem testing, or both in this situation?
- Which sheep in the flock are considered exposed or higher risk right now?
- Do we need to change lambing management, colostrum use, or pen sanitation immediately?
- Should we genotype breeding sheep for PRNP susceptibility as part of long-term control?
- What movement, sale, or identification restrictions might apply while this is being investigated?
- Are there USDA programs that can help with testing, tags, sample shipping, or flock certification?
How to Prevent Scrapie in Sheep
Prevention focuses on biosecurity, lambing management, traceability, and breeding decisions. The highest-risk period for spread is around lambing, so keep lambing areas as clean and controlled as possible. Remove placentas, birth fluids, and heavily soiled bedding promptly, and avoid exposing newborn lambs to contaminated pens.
Work with your vet on a flock plan that reduces risk from purchased animals and unknown-status additions. Limit commingling at markets, fairs, and shared facilities when possible. Keep accurate records, use official identification, and know where replacement animals came from.
For breeding flocks, ask your vet whether PRNP genotyping makes sense. Selecting for more resistant genotypes can be part of a long-term prevention strategy in sheep, but it should be used alongside surveillance and sound management rather than as a stand-alone fix.
If a mature sheep dies on-farm or is euthanized after neurologic signs or unexplained weight loss, discuss scrapie testing instead of routine disposal alone. APHIS encourages submission of samples from adult sheep and may provide tags, shipping materials, and testing support in eligible situations. Early reporting protects your flock, neighboring flocks, and future movement options.