CJD is a prion disease that leads to an irreversible neurological decline. While a gross inspection of a brain with CJD may not reveal any obvious abnormalities, other than cerebral atrophy, the micro-pathologic finding of spongiform changes is almost pathognomonic. Neuronal loss and gliosis can also be present. HIV infection of the brain leads to macrophages and multinucleated giant cells in the perivascular spaces in white matter. Alzheimer’s disease presents with intracellular neurofibrillary tangles and extracellular amyloid plaques. Rabies infection can lead to intracellular Negri bodies and HSV infection can lead to Cowdry inclusions.