This fact sheet was developed by students enrolled in Purdue's ANSC 442 Sheep Management course in Spring 2002, as a semester project. These fact sheets provide useful information on various topics related to sheep. View the list of fact sheets.


(Transmissible Spongiform Encephalopathy)

Definition: A fatal, degenerative disease affecting the central nervous system of sheep and goats.

History: In 1947, the first case of Scrapie in the United States was diagnosed in a flock in Michigan. The herd owner acquired his sheep from a flock in Canada, which had its origins in Europe. This Suffolk flock was the start of our troubles.

Data acquired in July 2001, shows that since 1947, there have been more than 1,000 flocks in the country diagnosed with this disease.

Disease Agent: 3 Theories

  1. Virus with unusual characteristics
  2. Prion (which is a malformed protein in the brain)
  3. Virino (a very small piece of DNA that acts like a virus)

Want to know more about prions? Check out these sites:

Breeds Affected:

Suffolk (87%)
Hampshire (6%)
Other Breeds (7%) This includes Cheviot, Border Leister, Corriedale, Rambouillet, Dorset, Montadale, Merino, North Country Cheviot, Cotswold, Finnsheep, Shropshire, and Southdown. Crosses of these breeds are also susceptible.

How do you know if your sheep have Scrapie?

Loss of coordination
Itching and Rubbing
Behavior Changes
Hypersensitivity to sound & light
Wool pulling
Lip Smacking
Weight loss despite retention of appetite

Where does Scrapie come from?

3 Types of Transmission:
Lateral: From one animal to another
Maternal: From dam to her offspring through parturition and fluids associated
Vertical: From parent to offspring via germplasm
**Combination of Lateral and Maternal is believed to be the main mode of transmission.

What do you do if you suspect your sheep are infected?

Is there a live-animal test available?

Currently, researchers have developed a test which would measure the amount of prions in the lymphoid tissue of the third eyelid. At this time, the test is still undergoing validation.

The only positive way to determine if your sheep are infected is to do a necropsy. The brain, spinal cord, and other tissue areas are evaluated for abnormal prion content.

For more info on the 3rd Eyelid Test:

Genetic Testing

Research has shown that certain breeds can show resistance to scrapie. However, because there are at least 15 different strains, the animal may only be resistant to one. Genetic testing is gaining popularity in identifying resistant sheep. This is done by analyzing codons that are active in synthesizing prion proteins.

Example: On codon 171, genotype RR and RQ are resistant, where as QQ is susceptible. This is a test used currently in Suffolks.

Preventing Scrapie

What is the Eradicate Scrapie Program?

This program was designed by the USDA Plant and Animal Health Inspection Service (APHIS) to officially eradicate scrapie from the United States.

What do you as a producer need to do to comply?

  1. Determine if your animals need to be tagged.

  3. Request a premise or flock I.D. number by calling your local APHIS Veterinary service office

  4. Determine which I.D. system works best for you. Tags may be custom ordered from an approved company or received directly from APHIS free of charge, but only for the first 2 years of the program. Tattoos are also an option.

  5. Set up a record keeping system to record the tags or other I.D. These records must be kept for a 5 year minimum.

  6. Apply official I.D. before your sheep or goat leaves your farm.

  7. Get a health certificate no more than 30 days before shipment.


Where can you go for more information?

Information on this page was compiled with permission from the National Institute for Animal Agriculture and from the USDA Animal Plant and Health Inspection Service (APHIS).

Picture used with permission, courtesy of Dr. Leon Thacker


This site was created by:
Kristen Fergot
Cara Hines
Becky Mitchell
Claire Uebbing