Although parenteral inoculation is the most reliable means of
inducing transmissible spongioforms encephalopathy, other routes
can also cause infection.
Scrapie, the prototype of transmissible encephalopahties, is thought to
spread in nature by ingestion. In mice infected by this route, there is
early replication of the infectious agent in the Peyer's patches
followed by spread tot he spinal cord, probably via gastrintestinal
nerves.
see: Kimberlin RH, Walker CA. Pathogenesis of scrapie in mice
after intragastric infection. Virus Res 12:213-220,1989.
WB Thomas DVM