ALL PRION IMAGES: possible routes of transmission of BSE prions
from cows to the human brain. Scheme of the possible
transmission routes of BSE prions from cows to the human brain.
The image above is 400 pixels across and the original is 3,017
pixels across. This simplified diagram shows the likely routes
of BSE prions from their amplification through cows to their
entry to the human brain. The prions are represented by the
purple particles streaming around the picture. At top left "O"
represents the origin of BSE prions. This has not been
established with certainty. The prions are then shown passing
from one cow to another (BSE infected cattle were fed to other
cows). Contaminated meat (and possibly other bovine derivatives)
then carried the prions to humans. In the human gut (bottom
left) prions may be taken up by lymphoid tissues (Peyer's
patches). The prions are then ferried around the body in
lymphocytes "L". Prion replication is thought to occur in
lymphoid tissues, especially the spleen "S". Nerves "N"