# Persistence of ovine scrapie infectivity in a farm environment following cleaning...



## terry (Sep 13, 2002)

These data suggest that recommended current guidelines for the decontamination of farm buildings following outbreaks of scrapie do little to reduce the titre of infectious scrapie material and that environmental recontamination could also be an issue associated with these premises. 

Scrapie Sheep Goats Transmissible spongiform encephalopathies (TSE) Accepted October 12, 2014. Published Online First 31 October 2014

http://veterinaryrecord.bmj.com/content/early/2014/10/31/vr.102743.abstract 


2012 

PO-039: A comparison of scrapie and chronic wasting disease in white-tailed deer 

Justin Greenlee, Jodi Smith, Eric Nicholson US Dept. Agriculture; Agricultural Research Service, National Animal Disease Center; Ames, IA USA 

snip...

The results of this study suggest that there are many similarities in the manifestation of CWD and scrapie in WTD after IC inoculation including early and widespread presence of PrPSc in lymphoid tissues, clinical signs of depression and weight loss progressing to wasting, and an incubation time of 21-23 months. Moreover, western blots (WB) done on brain material from the obex region have a molecular profile similar to CWD and distinct from tissues of the cerebrum or the scrapie inoculum. However, results of microscopic and IHC examination indicate that there are differences between the lesions expected in CWD and those that occur in deer with scrapie: amyloid plaques were not noted in any sections of brain examined from these deer and the pattern of immunoreactivity by IHC was diffuse rather than plaque-like. 

*** After a natural route of exposure, 100% of WTD were susceptible to scrapie. 

Deer developed clinical signs of wasting and mental depression and were necropsied from 28 to 33 months PI. Tissues from these deer were positive for PrPSc by IHC and WB. Similar to IC inoculated deer, samples from these deer exhibited two different molecular profiles: samples from obex resembled CWD whereas those from cerebrum were similar to the original scrapie inoculum. On further examination by WB using a panel of antibodies, the tissues from deer with scrapie exhibit properties differing from tissues either from sheep with scrapie or WTD with CWD. Samples from WTD with CWD or sheep with scrapie are strongly immunoreactive when probed with mAb P4, however, samples from WTD with scrapie are only weakly immunoreactive. In contrast, when probed with mAbs 6H4 or SAF 84, samples from sheep with scrapie and WTD with CWD are weakly immunoreactive and samples from WTD with scrapie are strongly positive. This work demonstrates that WTD are highly susceptible to sheep scrapie, but on first passage, scrapie in WTD is differentiable from CWD. 

http://www.landesbioscience.com/journals/prion/03-Prion6-2-Transmission-and-strains.pdf

2011 

*** After a natural route of exposure, 100% of white-tailed deer were susceptible to scrapie. 

http://www.usaha.org/Portals/6/Reports/2011/report-cwal-2011.pdf

Scrapie in Deer: Comparisons and Contrasts to Chronic Wasting Disease (CWD) 

Justin J. Greenlee of the Virus and Prion Diseases Research Unit, National Animal Disease Center, ARS, USDA, Ames, IA 

snip...

This highlights the facts that 

1) prior to the onset of clinical signs PrPSc is widely distributed in the CNS and lymphoid tissues and 

2) currently used diagnostic methods are sufficient to detect PrPSc prior to the onset of clinical signs. 

The results of this study suggest that there are many similarities in the manifestation of CWD and scrapie in white-tailed deer after IC inoculation including early and widespread presence of PrPSc in lymphoid tissues, clinical signs of depression and weight loss progressing to wasting, and an incubation time of 21-23 months. Moreover, western blots (WB) done on brain material from the obex region have a molecular profile consistent with CWD and distinct from tissues of the cerebrum or the scrapie inoculum. However, results of microscopic and IHC examination indicate that there are differences between the lesions expected in CWD and those that occur in deer with scrapie: amyloid plaques were not noted in any sections of brain examined from these deer and the pattern of immunoreactivity by IHC was diffuse rather than plaque-like. After a natural route of exposure, 100% of white-tailed deer were susceptible to scrapie. Deer developed clinical signs of wasting and mental depression and were necropsied from 28 to 33 months PI. Tissues from these deer were positive for scrapie by IHC and WB. Tissues with PrPSc immunoreactivity included brain, tonsil, retropharyngeal and mesenteric lymph nodes, hemal node, Peyers patches, and spleen. While two WB patterns have been detected in brain regions of deer inoculated by the natural route, unlike the IC inoculated deer, the pattern similar to the scrapie inoculum predominates. 

http://www.usaha.org/Portals/6/Reports/2011/report-cwal-2011.pdf 

2011 Annual Report 

Research Project: TRANSMISSION, DIFFERENTIATION, AND PATHOBIOLOGY OF TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHIES Location: Virus and Prion Research Unit 

2011 Annual Report 

In Objective 1, Assess cross-species transmissibility of transmissible spongiform encephalopathies (TSEs) in livestock and wildlife, numerous experiments assessing the susceptibility of various TSEs in different host species were conducted. Most notable is deer inoculated with scrapie, which exhibits similarities to chronic wasting disease (CWD) in deer suggestive of sheep scrapie as an origin of CWD. 

snip... 

4. Accomplishments 

1. Deer inoculated with domestic isolates of sheep scrapie. Scrapie-affected deer exhibit 2 different patterns of disease associated prion protein. In some regions of the brain the pattern is much like that observed for scrapie, while in others it is more like chronic wasting disease (CWD), the transmissible spongiform encephalopathy typically associated with deer. 

his work conducted by ARS scientists at the National Animal Disease Center, Ames, IA suggests that an interspecies transmission of sheep scrapie to deer may have been the origin of CWD. This is important for husbandry practices with both captive deer, elk and sheep for farmers and ranchers attempting to keep their herds and flocks free of CWD and scrapie. 

http://ars.usda.gov/research/projects/projects.htm?ACCN_NO=411467&showpars=true&fy=2011 

White-tailed Deer are Susceptible to Scrapie by Natural Route of Infection 

Jodi D. Smith, Justin J. Greenlee, and Robert A. Kunkle; Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS 

snip...

This work demonstrates for the first time that white-tailed deer are susceptible to sheep scrapie by potential natural routes of inoculation. In-depth analysis of tissues will be done to determine similarities between scrapie in deer after intracranial and oral/intranasal inoculation and chronic wasting disease resulting from similar routes of inoculation. 

see full text ; 

http://www.usaha.org/Portals/6/Reports/2010/report-cwal-2010.pdf 


Monday, November 3, 2014 

Persistence of ovine scrapie infectivity in a farm environment following cleaning and decontamination

http://transmissiblespongiformencephalopathy.blogspot.com/2014/11/persistence-of-ovine-scrapie.html


----------

