Pathogenesis of mouse scrapie: evidence for spread of infection from central to peripheral nervous system.

The onset of replication has been studied in spinal cord, dorsal root ganglia and spinal nerves of CW mice infected intraperitoneally with the 139A strain of scrapie. The patterns obtained suggest a centrifugal spread of infection from central to peripheral nervous systems. Infectivity titres in the peripheral nervous system reached a plateau long before the end of the incubation period, and the maximum titres were much lower than in the central nervous system. This suggests that there is a restriction of replication in the peripheral nervous system similar to that already known in extraneural tissues.