Visual pathology in animal prion diseases

Prion diseases, also known as the transmissible spongiform encephalopathies (TSEs), are a group of slowly developing neurodegenerations occurring in human and animals. Prion diseases can be transferred between animals, humans, from humans to animals, and from animals to humans. As a result, the central nervous system is attacked, resulting in microglia activation, astrocytosis, prion plaque deposition, and neuronal degeneration. Prion also targets on the eye and brain visual system. In scrapie-infected sheep, chronic wasting disease (CWD)-infected mule deer, and experimental animals infected with scrapie, transmissible mink encephalopathy (TME), and Creutzfeldt-Jakob disease (CJD), damage has been found in the outer and inner nuclear layers of the retina, brain stem, optic nerve, optic tract, optic radiation and visual cortex. This article reviews the prion agent and infectivity in the eye and brain visual system, and the visual and oculomotor pathology in animal prion diseases. Effects of PrP genotypes and PrPSc types on visual and oculomotor disorders will be discussed.