Prions are primarily found in the brain, the spinal cord and the immune system. British cows are thought to have developed the prion disease bovine spongiform encephalopathy (BSE) by eating ground-up brains, spleens and similar material. Other body parts were thought to be relatively safe for consumption.

Where are prions found?

While prion diseases are mostly associated with the brain, scientists have found abnormal infectious prion proteins in other organs, including the spleen, kidney, lungs, and liver.

What body part contains prions?

In human beings the abnormal prion has been reported in the brain, tonsils, spleen, lymph node, retina, and proximal optic nerve. Infectivity, although present in peripheral tissues, is at lower levels than in the central nervous system (CNS).