Electron microscopic findings in brain of Rocky Mountain elk with chronic wasting disease.

We report here the electron microscopic findings in brain of Rocky Mountain elk with chronic wasting disease (CDW), a progressive and fatal neurological disorder of wild ruminants characterized neuropathologically by intraneuronal vacuolation, spongiform change of the neuropil and astrocytic hypertrophy and hyperplasia. Ultrastructural findings included membrane-bound vacuoles in neuronal elements, increased number of glial filaments, dystrophic neurites, numerous neuritic plaques, Hirano bodies and perikaryal inclusion bodies. Similar findings have been observed in CWD-affected mule deer, as well as in bovine spongiform encephalopathy, and in natural and experimental scrapie and Creutzfeldt-Jakob disease indicating a common etiopathogenesis.