Submitted to: Scrapie Epidemiology and Program Management Course Handbook
Publication Type: Government Publication
Publication Acceptance Date: 5/5/1999
Publication Date: N/A
Interpretive Summary: Scrapie, a fatal transmissible disease of sheep and goats, is currently diagnosed by post mortem examination of brain tissue from clinically ill animals, typically 3 to 5 year old ewes. A team of scientists, pathologists and veterinarians from ARS and WSU has developed a non-invasive live animal test to identify the disease associated protein marker (the prion) in lymphoid tissue collected from the third eyelid of sheep. A biopsy of the tissue is taken following local anesthesia of the eye. This film and training manual describe and illustrate (1) effective restraint methods for biopsy collection; (2) the collection techniques and required materials; (3) test validation methods.
Technical Abstract: Scrapie is a fatal neurologic disease of sheep and goats. The disease is diagnosed by post mortem examination of neural tissue for characteristic changes in cell number or morphology, and deposition of the prion protein in the midbrain. Control of scrapie has been limited by the lack of a live animal test that could be used to diagnose the disease in sheep during the 3 to 5 year incubation period. Prion proteins accumulate in the follicular dendritic cells of lymphoid tissues as early as 12 to 14 months of age. A live animal test based on monoclonal antibody detection of prion proteins in the nictitating membrane lymphoid follicles of young adult sheep is in the validation stage. This training manual and videotape demonstrate the biopsy technique, required instruments and accessories, proper restraint of the sheep, the gross anatomy of the lymphoid tissue in the eyelid, and the appropriate handling of potentially infectious tissues and instruments.