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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Virus and Prion Research » Research » Publications at this Location » Publication #122389
Title: PREVENTING EXPERIMENTAL VERTICAL TRANSMISSION OF SCRAPIE BY EMBRYO TRANSFER

Author
item WANG, S - UTAH STATE UNIVERSITY
item FOOTE, W - UTAH STATE UNIVERSITY
item SUTTON, D - USDA, APHIS, VET. SERV.
item MACIULIS, A - UTAH STATE UNIVERSITY
item Miller, Janice
item EVANS, R - UTAH STATE UNIVERSITY
item HOLYOAK, G - OKLAHOMA STATE UNIV
item CALL, J - UTAH STATE UNIVERSITY
item BUNCH, T - UTAH STATE UNIVERSITY
item TAYLOR, W - USDA, APHIS, NVSL

Submitted to: Theriogenology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/1/2001
Publication Date: 7/1/2001
Citation: N/A

Interpretive Summary: The transmissible spongiform encephalopathies (TSEs) are a group of diseases that affect the brain and spinal cord of several mammalian species. The disease in sheep, known as scrapie, has been recognized for almost 300 years in some parts of Europe but was not seen in the United States until 1947. Several countries around the world, including the United States, have undertaken various kinds of control programs to eradicate scrapie, and most of them require the complete destruction of affected flocks. In order to save valuable genetic material from such flocks, it would be useful to know if embryos could be transferred from affected ewes to ewes in scrapie-free flocks without transmitting the disease. In this study, embryos that had been collected from ewes with scrapie were washed according to an internationally accepted standard and transferred to scrapie-free ewes. Sixty-eight lambs resulted from these transfers and 44 of the lambs survived to 60 months of age. During this time none of the scrapie-free recipient ewes and none of their offspring developed clinical signs of scrapie. These results indicate that embryos can be transferred from ewes in a scrapie-affected flock to ewes in a scrapie-free flock without risk of transmitting the disease. Use of this method would enable sheep producers to preserve valuable blood lines from a flock that must be destroyed in efforts to eradicate scrapie from a sheep population.

Technical Abstract: This study investigated whether the transmission of scrapie in sheep can be prevented using embryo transfer. Embryos were collected from 38 donor ewes in a Suffolk sheep flock that had a high incidence of naturally occurring scrapie. After treatment with a sanitary procedure (embryo washing) recommended by the International Embryo Transfer Society, the embryos were transferred to 58 scrapie-free recipient ewes. Ninety-four offspring were produced, 68 of which resulted from embryos collected from scrapie-positive ewes, as determined by histopathological and/or immunohistochemical examination. Forty-four of the 68 lambs survived to 60 months of age. During this observation period, none of the recipient ewes and none of their offspring developed clinical signs suggestive of scrapie. We conclude that under the conditions of this study, scrapie was not transmitted to offspring via the embryo nor was the infective agent transmitted to recipient ewes during embryo transfer procedures.