Photoreceptor degeneration during infection with various strains of the scrapie agent in hamsters.

Hamsters were inoculated intracerebrally with the 22C, 79A, and ME7 strains of the scrapie agent to compare the effects on the retina with those caused by strain 263K. The animals developed clinical signs of encephalopathy. Photoreceptor degeneration occurred in all experimental animals. The changes were similar to those seen in animals infected with the 263K strain of scrapie although somewhat more variable and less extensive