Chronic Wasting Disease in a Wisconsin White-Tailed Deer Farm

Abstract

Abstract. In September 2002, chronic wasting disease (CWD), a prion disorder of captive and wild cervids, was diagnosed in a white-tailed deer (Odocoileus virginianus) from a captive farm in Wisconsin. The facility was subsequently quarantined, and in January 2006 the remaining 76 deer were depopulated. Sixty animals (79%) were found to be positive by immunohistochemical staining for the abnormal prion protein (PrP CWD ) in at least one tissue; the prevalence of positive staining was high even in young deer. Although none of the deer displayed clinical signs suggestive of CWD at depopulation, 49 deer had considerable accumulation of the abnormal prion in the medulla at the level of the obex. Extraneural accumulation of the abnormal protein was observed in 59 deer, with accumulation in the retropharyngeal lymph node in 58 of 59 (98%), in the tonsil in 56 of 59 (95%), and in the rectal mucosal lymphoid tissue in 48 of 58 (83%). The retina was positive in 4 deer, all with marked accumulation of prion in the obex. One deer was considered positive for PrP CWD in the brain but not in the extraneural tissue, a novel observation in white-tailed deer. The infection rate in captive deer was 20-fold higher than in wild deer. Although weakly related to infection rates in extraneural tissues, prion genotype was strongly linked to progression of prion accumulation in the obex. Antemortem testing by biopsy of rectoanal mucosal-associated lymphoid tissue (or other peripheral lymphoid tissue) may be a useful adjunct to tonsil biopsy for surveillance in captive herds at risk for CWD infection.

Genetic susceptibility to chronic wasting disease in free-ranging white-tailed deer: Complement component C1q and Prnp polymorphisms

“…For C1qA, B, and C, we also controlled for the effects of Prnp. Specifically, we analyzed a special a priori case of Model I where we added an indicator of the presence or absence of Serine (S) at amino acid 96 of the Prnp gene because of the support for the importance of this amino acid position in CWD susceptibility and progression (Johnson et al, 2006;Keane et al, 2008a). We report these results with the Model I results.…”

“…Because other studies have reported a relationship between disease progression (stage) and Prnp polymorphisms (e.g., Johnson et al, 2006;Keane et al, 2008a), we tested for associations between early disease stage (lymph node infection only) versus later stage (lymph node and brain infection) and C1q and Prnp polymorphisms using Fisher's exact test (two-sided). We performed these analyses on a gene-wise (Model III) basis.…”

“…As Prnp polymorphisms have been demonstrated to be associated with CWD susceptibility (O'Rourke et al, 1999(O'Rourke et al, , 2004Johnson et al, 2003Johnson et al, , 2006Jewell et al, 2005;Fox et al, 2006;Hamir et al, 2006;Keane et al, 2008a; but see Perucchini et al, 2008), we simultaneously evaluated Prnp genotypes to account for the effect of this gene in C1q analyses and to explore potential inter-locus associations. Because, as discussed above, non-random mating and unknown pedigrees in free-ranging populations create a risk of spurious results due to admixture we used microsatellite data to identify closely related CWDpositive and CWD-negative deer to serve as matched cases and controls.…”

High prevalence of scrapie in a dairy goat herd: tissue distribution of disease-associated PrP and effect ofPRNPgenotype and age

“…Post-mortem detection of PrP d in the RAMALT was achieved in a low percentage [13]), and similar ones in chronic wasting disease of cervids [21,33]. Whether this is a feature of goat scrapie in general or a peculiarity of this outbreak is unknown but, in any case, the frequency of detection of PrP d in the RAMALT rises to 84.0% when goats with widespread LRS involvement -but still at preclinical stagesare considered.…”

Deer density and disease prevalence influence transmission of chronic wasting disease in white‐tailed deer

“…Chronic wasting disease status was determined for deer !1 year of age and for most fawns. To test for CWD, WIDNR staff removed the retropharyngeal lymph nodes and obex from harvested deer and personnel at the Wisconsin Veterinary Diagnostic Laboratory used immunohistochemistry or plate ELISA to determine CWD status (Keane et al 2008). We used the proportion of CWD-positive yearling deer (.1, ,2 years of age at harvest) harvested in section i (2.59 km 2 ) as a measure of incidence (probability of acquiring detectable infection) from birth to harvest.…”