Neuropathology of Chronic Wasting Disease of Mule Deer (Odocoileus hemionus) and Elk (Cervus elaphus nelsoni)

Abstract

Abstract. Th e path ology of the centra l ner vou s system of nine mul e deer (Odocoileus hemionus) and six elk (Cervus elaphus nelsoni) with chro nic wasting d isease, a spongiform encepha lopathy o f mul e deer and elk, was stud ied by light microscop y. Lesion s were sim ilar in both species and were characterized by spo ngiform transformati on of gray matter , intracytopl asm ic vacuolati on of neuron s, neuronal degenerati on and loss, astro cytic hypertroph y and hyperpl asia , occur rence of am yloid plaques, and absence of significant inflammatory respon se. Distributi on and severity of lesion s were eva luated at 57 locati on s; there were only min or differences between deer and elk. Co nsis tent, severe lesion s occ urred in olfacto ry tub ercle and cortex, hypoth alamus, and the parasym path etic vaga l nucleus of deer, and sectio ns examined from these region s would be sufficient to esta blish a di agnosis ofchron ic wasting di sease. Lesions were mi lder in these locat ions in elk but were sufficiently appare nt to be of diag nos tic va lue. Other differe nces included increased severi ty of lesion s some th alamic nuclei in elk in contrast to deer, the occurrence of amy loid plaqu es dem on str able by hem at oxylin and eosi n and histoche mica l sta ins in deer in contrast to elk, and th e presence of mild white matter lesion s in elk but not in deer. Lesion s of chro nic wasting di sease were qu alit ati vely compa rab le to those of scrapie, bovin e spo ngiform encepha lopa thy, tran smi ssible m ink ence phalopathy, and the human spongiform encephalopa thies. To pographic di str ibution and lesion seve rity of chro nic wasting di sease were most similar to those of scrapie and bo vin e spo ngiform enceph alop ath y. Durati on o f clini cal di sease did not signifi cantly influence lesion di stribution or severi ty in eithe r spec ies.Key words: Central ner vou s system; Cervus elaphus nelsoni ;elk; mul e deer ; Odocoileus hem ionus;spo ngiform ence pha lopa thy.Chronic wasting disease (CWD), a spontaneous neurolo gic disease of captive mul e deer (Odocoileus hemionus) and Rocky Mountain elk (Cervus elaphus nelsoni), has been recogniz ed since 1967 and 1979 , respectively, in wildlife facilities in Colorado and Wyoming.21.22 Th e disease is characterized by emaciation, changes in beha vior , and excessive salivation in both species and in deer, addi tio nally by polydip sia and polyuria. Clinical course is from severa l weeks to 8 months and the disease is invariably fatal. At necropsy, affected anima ls are emaci ated but other gross lesions have not been found consistently. Ruminal contents of deer are excessive ly fluid, reflecting polydip sia in this species. Various oth er gross changes, parti cularl y aspiration pneumonia, are inconsistentl y present and hav e been considered the result of int ercurrent or seconda ry disease pro cesses. Consistent microscopi c alteration s have been found only in the central nervous system (CNS) and ha ve been characterized as a spongiform encephalopath...

A Case of Chronic Wasting Disease in an Elk Imported to Korea from Canada.

“…The pattern and distribution of histologic lesions observed in this case were very similar to those of the previous reports on CWD [7,11]. Bilaterally symmetrical neuronal vacuolation, spongiform change of the gray matter, and astrocytosis are pathognomonic for CWD.…”

“…Clinical signs last from several weeks to 8 months before the animal dies, but sometimes animals may not show any sign except for acute pneumonia or respiratory distress. Characteristic histopathologic change of CWD, spongiform encephalopathy, is found in brain stem, particularily the dorsal motor nucleus of the vagus nerve [10,11].…”

A processed pseudogene contributes to apparent mule deer prion gene heterogeneity

“…Clinical signs include weight loss, behavioral changes, polydipsia and polyuria, and excessive salivation (Williams and Young, 1982). Pathological changes in the central nervous system include spongiform encephalopathy and neuronal degeneration (Williams and Young, 1993). First reported in captive mule deer from a small region of the Western United States (Williams and Young, 1980), CWD has been endemic in contiguous areas of Colorado and Wyoming for more than 30 years Williams and Miller, 2002) with more recent reports of disease in free ranging deer in Nebraska, South Dakota, Wisconsin, Illinois and New Mexico.…”

Preliminary Observations of Genetic Susceptibility of elk (Cervus Elaphus Nelsoni) to Chronic Wasting Disease by Experimental Oral Inoculation

“…All 4 clinically ill animals had microscopic lesions of spongiform encephalopathy (SE) characterized by intraneuronal vacuolation, microcavitation of gray matter, neuronal degeneration, and mild astrocytosis, as described in deer and elk. 13,16,17 The microcavitation of gray matter was more prevalent than the intraneuronal vacuolation and neuronal degeneration (Fig. 1).…”