<i>PRNP</i> sequence of the reindeer used in this study compared with mule deer, white-tailed deer, Rocky Mountain elk, and moose.

<p>Reindeer are polymorphic at codons 2 (M/V), 129 (S/G), 138 (S/N), and 169 (M/V). <i>PRNP</i> polymorphisms have also been reported in Rocky Mountain elk (132 M/L), mule deer (20 D/G, 225 S/F), white-tailed deer (95 Q/H, 96 G/S, 116 A/G, 226 Q/R, and 230 Q/L) and moose 209 (M/I) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0039055#pone.0039055-Baeten1" target="_blank">[11]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0039055#pone.0039055-ORourke1" target="_blank">[41]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0039055#pone.0039055-Wilson1" target="_blank">[44]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0039055#pone.0039055-Heaton1" target="_blank">[45]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0039055#pone.0039055-Jewell1" target="_blank">[46]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0039055#pone.0039055-ORourke2" target="_blank">[47]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0039055#pone.0039055-Brayton1" target="_blank">[48]</a>.</p

Western immunoblot of PrP^res in the brainstem of reindeer compared to elk and white-tailed deer CWD inocula.

<p>Reindeer 12 (lane 4) and reindeer 47 (lane 5) developed terminal CWD at 18.5 and 20 mpi. Lane 1– molecular weight marker (kDa), lane 2– CWD in elk, lane 3– CWD in white-tailed deer, lane 4– CWD in reindeer 12, lane 5– CWD in reindeer 47, lane 6– negative control elk.</p

Tissue distribution of PrP^CWD and histopathology in clinically affected reindeer orally inoculated with CWD from white-tailed deer.

<p>IHC detection of PrP^CWD using MAb F99/97.6.1 demonstrates: (A) immunolabeling associated with tingible body macrophages and follicular dendritic cells in a RAMALT biopsy taken at 13.4 mpi, (C) punctate staining in cardiomyocytes, (D) widespread particulate deposits in the dorsal vagal nucleus, (E) immunolabeling within a ganglion adjacent to the submandibular salivary gland, (F) granular PrP^CWD in submucosal and myenteric plexuses of the ileum and (G) amongst glomerular lymphocytic infiltrates. (B) Haematoxylin and eosin stained section of the dorsal vagal nucleus reveals vacuolation of the neuropil. (H) PET blot of the obex demonstrating abundant widespread PrP^CWD filling the dorsal vagal nucleus and surrounding nuclei. Bars, 150 µm (A); 65 µm (B,D,E); 24 µm (C,G); 92 µm (F); 2.4 mm (H).</p

PrP^CWD distribution in tissues of reindeer orally inoculated with brain tissue from CWD-infected white-tailed deer.

a<p>PrP^CWD was detected by IHC with MAb F99/97.6.1 and a commercially available TSE ELISA kit and results are expressed as PrP^CWD present (+) or not detected (−).</p><p>RAMALT, recto-anal mucosa-associated lymphoid tissue; LN, lymph node.</p

Summary of results from reindeer orally inoculated with CWD from elk or white-tailed deer.^a

a<p>ELISA  =  enzyme-linked immunosorbent assay; IHC  =  immunohistochemistry; LN  =  lymph node; mpi  =  months post-inoculation; NA  =  data not available; RAMALT  =  Recto-anal mucosa associated lymphoid tissue; WB  =  Western blot; WTD  =  White-tailed deer.</p>b<p>Time (mpi) to first clinical signs of neurological disease if observed.</p>c<p>Deduced amino acids at codons 2-129-138-169. V =  Valine; M =  Methionine; G =  Glycine; S =  Serine; N =  Asparagine.</p>d<p>IHC conducted on RAMALT or obex tissue using mAb F99. The time of last RAMALT sampling is listed in parentheses (mpi) for animals with a negative IHC result, while the time of the first positive RAMALT biopsy is listed for the positive animals.</p>e<p>Conducted on obex or retropharyngeal lymph node and reported as positive (+) or negative (–) with optical density (OD) in parentheses from a commercially available ELISA kit (negative OD cut-off  = 0.21).</p>f<p>Animal 17 remains alive at 26 mpi with no evidence of clinical signs or PrP^CWD in RAMALT biopsy.</p

Biodegradation of Prions in Compost

Composting may serve as a practical and economical means of disposing of specified risk materials (SRM) or animal mortalities potentially infected with prion diseases (transmissible spongiform encephalopathies, TSE). Our study investigated the degradation of prions associated with scrapie (PrP^263K), chronic waste disease (PrP^CWD), and bovine spongiform encephalopathy (PrP^BSE) in lab-scale composters and PrP^263K in field-scale compost piles. Western blotting (WB) indicated that PrP^263K, PrP^CWD, and PrP^BSE were reduced by at least 2 log₁₀, 1–2 log₁₀, and 1 log₁₀ after 28 days of lab-scale composting, respectively. Further analysis using protein misfolding cyclic amplification (PMCA) confirmed a reduction of 2 log₁₀ in PrP^263K and 3 log₁₀ in PrP^CWD. Enrichment for proteolytic microorganisms through the addition of feather keratin to compost enhanced degradation of PrP^263K and PrP^CWD. For field-scale composting, stainless steel beads coated with PrP^263K were exposed to compost conditions and removed periodically for bioassays in Syrian hamsters. After 230 days of composting, only one in five hamsters succumbed to TSE disease, suggesting at least a 4.8 log₁₀ reduction in PrP^263K infectivity. Our findings show that composting reduces PrP^TSE, resulting in one 50% infectious dose (ID₅₀) remaining in every 5600 kg of final compost for land application. With these considerations, composting may be a viable method for SRM disposal