Secretary Glickman Announces New Test to Diagnose Scrapie in Live Sheep

Click here to read a USDA fact sheet on scrapie.

PULLMAN, Wash., April 9--USDA scientists have discovered that sheep eyelids hold the key to an easy, relatively inexpensive test for diagnosing scrapie, a fatal brain disease in sheep, Agriculture Secretary Dan Glickman announced today.

"This test will allow producers and veterinarians, for the first time, to easily detect scrapie in sheep before the animals show signs of the disease," said Glickman. "Until now, scrapie could only be confirmed by examining the brains of dead animals. Clearly, this is an important step toward controlling this disease."

Scrapie is a fatal, degenerative disease affecting the central nervous system of sheep and goats. There is no cure or treatment for scrapie and scientists do not fully understand how it is transmitted. Sheep can harbor the disease for up to five years before they show signs such as trembling, incoordination or scraping against objects. Under USDA regulations, producers with confirmed cases of scrapie in their flock often must destroy animals in an effort to eliminate the disease.

USDA estimates that the new eyelid test will be performed for about $25 per animal once it is commercially available. Current tests require biopsies of internal organs, which is more risky and can cost up to $500 per animal.

In developing the test, researchers at USDA's Agricultural Research Service discovered that the third eyelid in sheep collects prions, a type of protein believed to cause scrapie. They also designed a new antibody to identify prions in a sample of eyelid tissue. USDA has applied for patents on both discoveries.

"This is another good example of the tremendous impact that long-term investments in research can have on some of the toughest problems facing American agriculture," Glickman said.

ARS microbiologist Katherine I. O'Rourke led the Pullman, Washington-based team responsible for this important work. Others on the team include Donald P. Knowles, who leads the Pullman lab, Timothy V. Baszler and Steven M. Parish with Washington State University in Pullman, and Janice M. Miller at the ARS National Animal Disease Center in Ames, Iowa.

Scientific contact: Donald P. Knowles, Agricultural Research Service, Animal Diseases Research Unit, 337 Bustad, WSU, Pullman, WA 99164-7030. Phone (509) 335-6022; fax (509) 335-8328, dknowles@vetmed.wsu.edu.