FIBRILS IN BRAINS OF ROCKY-MOUNTAIN ELK WITH CHRONIC WASTING DISEASE CONTAIN SCRAPIE AMYLOID

Chronic wasting disease (CWD), a progressive, fatal neurological disor der of captive mule deer and Rocky Mountain elk, is characterized neur opathologically by spongiform change in the neuropil, intraneuronal va cuolation and astrocytic hypertrophy and hyperplasia. Recently, scrapi e amyloid-immunoreactive plaques have been demonstrated in brain tissu es of CWD-affected captive mule deer, Rocky Mountain elk and hybrids o f captive mule deer and white-tailed deer. We now report on the presen ce of abnormal fibrils isolated from brain tissues of Rocky Mountain e lk using negative-stain electron microscopy. These fibrils resemble th ose found in scrapie-infected hamster brain. Furthermore, protein band s with relative molecular masses of 26 to 30 kilodaltons were shown to be immunoreactive to antibodies raised against scrapie amyloid by Wes tern immunoblotting. Immuno-dot blot showed similar reactivity Our dat a support the clinical and pathological diagnosis of the disease and p rovide further evidence that CWD belongs to the subacute spongiform en cephalopathies.