INTRACEREBRAL TRANSMISSION OF SCRAPIE TO CATTLE

To determine if sheep scrapie agent(s) in the United States would indu ce a disease in cattle resembling bovine spongiform encephalopathy, 18 newborn calves were inoculated intracerebrally with a pooled suspensi on of brain from 9 sheep with scrapie. Half of the calves were euthana tized I year after inoculation. All. calves kept longer than 1 year be came severely lethargic and demonstrated clinical signs of motor neuro n dysfunction that were manifest as progressive stiffness, posterior p aresis, general weakness, and permanent recumbency. The incubation per iod was 14-18 months, and the clinical course was 1-5 months. The brai n from each calf was examined for lesions and for protease-resistant p rion protein. Lesions were subtle, but a disease-specific isoform of t he prion protein was present in the brain of all calves. Neither signs nor lesions were characteristic of those for bovine spongiform enceph alopathy.