TPWD UPDATE CWD TSE Prion 49 confirmed cases and unwanted firsts for Texas
TPWD UPDATE CWD TSE Prion 49 confirmed cases and unwanted firsts Texas
News Release Media Contact: TPWD News, news@tpwd.texas.gov, 512-389-8030 March 31, 2017
TPWD Announces 2016-17 Season CWD Monitoring Results
Texas records first cases of disease in free-ranging whitetail, elk
AUSTIN – Texas recorded a couple of unwanted firsts for chronic wasting disease (CWD) during statewide surveillance efforts for the 2016-17 collection year, including detections in a free-ranging whitetail and a free-ranging elk.
The Texas Parks and Wildlife Department (TPWD) surpassed its statewide goal of 6,735 CWD samples, collecting 9,830 from hunter harvested and road kill deer, and other susceptible cervid species, between March 1, 2016 and Feb. 28, 2017. Sampling objectives were established by TPWD wildlife biologists based on deer densities within each of the 41 Deer Management Units (DMU) in Texas and other factors to establish sufficient confidence of detection if CWD were present within those localized populations.
TPWD wildlife staff collected CWD samples from a variety of locations including: road kill deer, deer processors, private ranches, wildlife management areas and state parks, and voluntary and mandatory hunter harvest check stations. Of the 9,830 samples collected, 23 percent were road kill. Exotic species that have been sampled include axis deer, fallow deer, red stag, sika, and elk; although there is no evidence that axis and fallow deer are susceptible to this disease.
Details about each CWD detection in Texas are available online.
Among the CWD positives detected in Texas this past season, some notable firsts:
The first confirmed case of CWD in a free-ranging Texas whitetail was detected in a hunter harvested 1 1/2 –year-old buck submitted for sampling within the Surveillance Zone 3 located in portions of Medina, Uvalde, and Bandera counties. The first known free-ranging elk in Texas to test positive for CWD, harvested by a hunter in Dallam County. The first known case of a captive-raised white-tailed deer in Texas that live tested “not detected” for CWD, but after being harvested by a hunter on a release site three months later tested positive for the disease. To date, Texas has recorded 49 confirmed cases of CWD, of which 26 were discovered in captive deer breeding pens, 5 were hunter harvested on breeder deer release sites, 16 were free-ranging mule deer, 1 was a free-ranging elk, and 1 was a free-ranging white-tailed deer.
“The good news is so far our sampling in the Tran-Pecos has only detected CWD in the Hueco Mountains area,” said Dr. Bob Dittmar, TPWD wildlife veterinarian. “Since 2012, the disease has been found in 13 mule deer out of 117 tested in the Hueco Mountains area for an 11 percent prevalence rate.”
Dittmar also expressed guarded confidence that CWD has not spread outside the Hueco Mountains area based on increased sampling in the surrounding ranges.
“The mandatory sampling in the Trans-Pecos SZ helped get an increase in sampling from the Delaware Mountains this year and while we have accumulated a decent number of samples around the Guadalupe Mountains, both remain areas of concern and we still need some more sampling out there.” he noted.
The state’s wildlife disease management response focuses on an early detection and containment strategy designed to limit the spread of CWD from the affected area and better understand the distribution and prevalence of the disease.
The detection of CWD in a free-ranging whitetail in Medina County this season resulted from enhanced voluntary testing of hunter harvested deer, allowing TPWD to initiate proactive measures aimed at containment rather than reactive steps targeting control.
“The more effective we are at containing this disease within a limited geographic area, the better it will be for our wildlife resources and all those who enjoy them,” Dittmar said. “We want to thank the Texas hunting community for its strong support of our management efforts; we cannot combat the spread of CWD without it.”
A detailed summary of CWD sampling for the 2016-17 collection season is available for review online.
2017-03-31
CWD Positives in Texas
Show entriesSearch:
CWD Positive
Year Confirmed CWD Positive
Confirmation Date Free Range / Captive County Source Species Sex Age
2016 2/18/2017 Breeder Deer-Released Medina Facility #4 white-tailed deer M 3.5
2016 2/17/2017 Free Range Hudspeth Mule Deer M 7.5
2016 2/17/2017 Free Range Hudspeth Mule Deer M 5.5
2016 2/9/2017 Free Range Hudspeth Mule Deer M 3.5
2016 2/9/2017 Free Range Hudspeth Mule Deer M 7.5
2016 1/24/2017 Free Range Medina white-tailed deer M 1.5
2016 1/18/2017 Free Range Hartley Mule Deer M 4.5
2016 1/18/2017 Breeder Deer-Released Uvalde Facility #3 white-tailed deer M 5.5
2016 1/18/2017 Breeder Deer-Released Uvalde Facility #3 white-tailed deer M 3.5
2016 1/6/2017 Free Range Dallam Mule Deer M 2.5
2016 1/6/2017 Free Range El Paso Mule Deer M 4.5
2016 12/6/2016 Free Range Dallam Elk M 8.5
2016 10/28/2016 Breeder Deer Uvalde Facility #3 white-tailed deer M 5.5
2016 10/28/2016 Breeder Deer Uvalde Facility #3 white-tailed deer F 4.5
2016 9/21/2016 Breeder Deer - Released Medina Facility #3 white-tailed deer M 3.5
2016 6/29/2016 Breeder Deer Medina Facility #4 white-tailed deer F 1
2016 6/29/2016 Breeder Deer Medina Facility #4 white-tailed deer M 1
2016 6/29/2016 Breeder Deer Medina Facility #4 white-tailed deer F 1
2016 6/29/2016 Breeder Deer Medina Facility #4 white-tailed deer M 1
2016 6/29/2016 Breeder Deer Medina Facility #4 white-tailed deer F 4
2016 6/29/2016 Breeder Deer Medina Facility #4 white-tailed deer F 4
2016 6/29/2016 Breeder Deer Medina Facility #4 white-tailed deer F 4
2016 6/29/2016 Breeder Deer Medina Facility #4 white-tailed deer F 4
2016 6/29/2016 Breeder Deer Medina Facility #4 white-tailed deer F 4
2016 6/29/2016 Breeder Deer Medina Facility #4 white-tailed deer F 4
2016 6/29/2016 Breeder Deer Medina Facility #4 white-tailed deer F 4
2016 6/29/2016 Breeder Deer Medina Facility #4 white-tailed deer F 4
2016 6/29/2016 Breeder Deer Medina Facility #4 white-tailed deer F 4
2016 4/13/2016 Breeder Deer Lavaca Facility #2 white-tailed deer M 3
2016 4/13/2016 Breeder Deer Lavaca Facility #2 white-tailed deer M 3
2016 4/13/2016 Breeder Deer Lavaca Facility #2 white-tailed deer M 3
2016 4/13/2016 Breeder Deer Lavaca Facility #2 white-tailed deer M 3
2016 4/1/2016 Breeder Deer Medina Facility #4 white-tailed deer F 4.5
2016 3/29/2016 Breeder Deer Medina Facility #3 white-tailed deer M 3
2016 2/4/2016 Breeder Deer - Released Medina Facility #3 white-tailed deer M 3
2015 3/25/2016 Free Range Hartley Mule Deer M 3.5
2015 3/18/2016 Free Range Hudspeth Mule Deer M 5.5
2015 9/14/2015 Breeder Deer Lavaca Facility #2 white-tailed deer M 3
2015 8/12/2015 Breeder Deer Medina Facility #1 white-tailed deer M 2.5
2015 8/6/2015 Breeder Deer Medina Facility #1 white-tailed deer M 2.5
2015 8/6/2015 Breeder Deer Medina Facility #1 white-tailed deer M 2.5
2015 6/30/2015 Breeder Deer Medina Facility #1 white-tailed deer M 2.5
2014 12/4/2014 Free Range Hudspeth Mule Deer M 4.5
2012 12/28/2012 Free Range Hudspeth Mule Deer M 3.5
2012 12/10/2012 Free Range Hudspeth Mule Deer M 4.5
2012 12/2/2012 Free Range Hudspeth Mule Deer M 5.5
2012 12/1/2012 Free Range Hudspeth Mule Deer M 4.5
2012 7/12/2012 Free Range Hudspeth Mule Deer F 6.5
2012 7/12/2012 Free Range Hudspeth Mule Deer F 4.5
>>>The first known case of a captive-raised white-tailed deer in Texas that live tested “not detected” for CWD, but after being harvested by a hunter on a release site three months later tested positive for the disease.<<<
yep, did not take a rocket scientist to see this coming. how many more?
WEDNESDAY, JULY 22, 2015
Texas Certified Chronic Wasting Disease CWD Sample Collector, like the Wolf Guarding the Henhouse Just got off the phone with TAHC, and I wanted to confirm this. but it seems true, that in the state of Texas, even if you are a Captive game farmer, breeder, part of the captive industry at all, if you want to sample your own cervid for cwd, instead of the TAHC, TPWD, or Doctor, all you have to do is pass the Certified CWD Sample Collector course, and bingo, you sample your own herd. ...tss
FRIDAY, JANUARY 27, 2017
TEXAS, Politicians, TAHC, TPWD, and the spread of CWD TSE Prion in Texas
CWD SURVEILLANCE TEXAS
SNIP...SEE FULL TEXT ;
2011 – 2012
Friday, October 28, 2011
CWD Herd Monitoring Program to be Enforced Jan. 2012 TEXAS
Greetings TAHC et al,
A kind greetings from Bacliff, Texas.
In reply to ;
Texas Animal Health Commission (TAHC) Announcement October 27, 2011
I kindly submit the following ;
Sunday, October 04, 2009
CWD NEW MEXICO SPREADING SOUTH TO TEXAS 2009 2009 Summary of Chronic Wasting Disease in New Mexico New Mexico Department of Game and Fish
Monday, March 26, 2012
Texas Prepares for Chronic Wasting Disease CWD Possibility in Far West Texas
Tuesday, July 10, 2012
Chronic Wasting Disease Detected in Far West Texas
Monday, February 11, 2013
TEXAS CHRONIC WASTING DISEASE CWD Four New Positives Found in Trans Pecos
***for anyone interested, here is some history of CWD along the Texas, New Mexico border, and my attempt to keep up with it...terry
snip...
see history CWD Texas, New Mexico Border ;
Monday, March 26, 2012
3 CASES OF CWD FOUND NEW MEXICO MULE DEER SEVERAL MILES FROM TEXAS BORDER
Texas 84th Legislative Session
Sunday, December 14, 2014
*** TEXAS 84th Legislature commencing this January, deer breeders are expected to advocate for bills that will seek to further deregulate their industry
TUESDAY, DECEMBER 16, 2014
Texas 84th Legislature 2015 H.R. No. 2597 Kuempel Deer Breeding Industry TAHC TPWD CWD TSE PRION
Wednesday, July 01, 2015
*** TEXAS Chronic Wasting Disease Detected in Medina County Captive Deer
Thursday, July 09, 2015
TEXAS Chronic Wasting Disease (CWD) Herd Plan for Trace-Forward Exposed Herd with Testing of Exposed Animals
Tuesday, July 21, 2015
*** Texas CWD Medina County Herd Investigation Update July 16, 2015 ***
Wednesday, July 22, 2015
Texas Certified Chronic Wasting Disease CWD Sample Collector, like the Wolf Guarding the Henhouse
Thursday, August 06, 2015
*** WE HAVE LOST TEXAS TO CWD TASK FORCE CATERING TO INDUSTRY
Friday, August 07, 2015
*** Texas CWD Captive, and then there were 4 ?
***raw and uncut***
Sunday, August 23, 2015
TAHC Chronic Wasting Disease CWD TSE Prion and how to put lipstick on a pig and take her to the dance in Texas
Saturday, October 03, 2015
TEXAS CHRONIC WASTING DISEASE CWD TSE PRION GOD MUST NOT BE A TEXAN 2002 TO 2015
Friday, October 09, 2015
Texas TWA Chronic Wasting Disease TSE Prion Webinars and Meeting October 2015
Thursday, September 24, 2015
TEXAS Hunters Asked to Submit Samples for Chronic Wasting Disease CWD TSE Prion Testing
*** I cannot stress enough to all of you, for the sake of your family and mine, before putting anything in the freezer, have those deer tested for CWD. ...terry
Thursday, November 05, 2015
*** TPW Commission Adopts Interim Deer Breeder Movement Rules
Saturday, November 14, 2015
TEXAS CAPTIVE BREEDER CHRONIC WASTING DISEASE CWD 2 MORE SUSPECTS DECTECTED BRINGING NUMBER TO 7 DETECTED IN CAPTIVE BREEDER (if/when the last two are confirmed).
Monday, November 16, 2015
*** TEXAS PARKS AND WILDLIFE DEPARTMENT EXECUTIVE DIRECTOR ORDER NO. 015-006
*** Chronic Wasting Disease (CWD) immediate danger to the white-tailed deer and mule deer resources of Texas
SATURDAY, JANUARY 23, 2016
Texas Chronic Wasting Disease Response Update and Interim Deer Management Permit Rules Recommended Adoption of Proposed Rules
Friday, February 05, 2016
*** TEXAS NEW CHRONIC WASTING DISEASE CWD CASE DISCOVERD AT CAPTIVE DEER RELEASE SITE
Saturday, April 02, 2016
*** TEXAS TAHC BREAKS IT'S SILENCE WITH TWO MORE CASES CWD CAPTIVE DEER BRINGING TOTAL TO 10 CAPTIVES REPORTED TO DATE
Friday, April 22, 2016
*** Texas Scrapie Confirmed in a Hartley County Sheep where CWD was detected in a Mule Deer
Wednesday, May 04, 2016
TPWD proposes the repeal of §§65.90 -65.94 and new §§65.90 -65.99 Concerning Chronic Wasting Disease - Movement of Deer Singeltary Comment Submission
SUNDAY, MAY 22, 2016
TEXAS CWD DEER BREEDERS PLEA TO GOVERNOR ABBOTT TO CIRCUMVENT TPWD SOUND SCIENCE TO LET DISEASE SPREAD
Friday, July 01, 2016
*** TEXAS Thirteen new cases of chronic wasting disease (CWD) were confirmed at a Medina County captive white-tailed deer breeding facility on June 29, 2016
Thursday, June 09, 2016
Scrapie Field Trial Experiments Mission, Texas, The Moore Air Force Base Scrapie Experiment 1964
How Did CWD Get Way Down In Medina County, Texas?
Confucius ponders...
Could the Scrapie experiments back around 1964 at Moore Air Force near Mission, Texas, could this area have been ground zero for CWD TSE Prion (besides the CWD cases that have waltzed across the Texas, New Mexico border near WSMR Trans Pecos region since around 2001)?
Epidemiology of Scrapie in the United States 1977
snip...
Scrapie Field Trial Experiments Mission, Texas
A Scrapie Field Trial was developed at Mission, Texas, to provide additional information for the eradication program on the epidemiology of natural scrapie. The Mission Field Trial Station is located on 450 acres of pastureland, part of the former Moore Air Force Base, near Mission, Texas. It was designed to bring previously exposed, and later also unexposed, sheep or goats to the Station and maintain and breed them under close observation for extended periods to determine which animals would develop scrapie and define more closely the natural spread and other epidemiological aspects of the disease.
The 547 previously exposed sheep brought to the Mission Station beginning in 1964 were of the Cheviot, Hampshire, Montadale, or Suffolk breeds. They were purchased as field outbreaks occurred, and represented 21 bloodlines in which scrapie had been diagnosed. Upon arrival at the Station, the sheep were maintained on pasture, with supplemental feeding as necessary. The station was divided into 2 areas: (1) a series of pastures and-pens occupied by male animals only, and (2) a series of pastures and pens occupied by females and young progeny of both sexes. ...
snip...see full text ;
Thursday, June 09, 2016
Scrapie Field Trial Experiments Mission, Texas, The Moore Air Force Base Scrapie TSE Prion Experiment 1964
How Did CWD Get Way Down In Medina County, Texas?
SATURDAY, JULY 09, 2016
Texas Intrastate – within state movement of all Cervid or Trucking Chronic Wasting Disease CWD TSE Prion Moratorium
Monday, July 18, 2016
Texas Parks Wildlife Dept TPWD HIDING TSE (CWD) in Deer Herds, Farmers Sampling Own Herds, Rapid Testing, False Negatives, a Recipe for Disaster
TUESDAY, AUGUST 02, 2016
TEXAS TPWD Sets Public Hearings on Deer Movement Rule Proposals in Areas with CWD Rule Terry S. Singeltary Sr. comment submission
Wednesday, September 28, 2016
TPWD CWD Sample Collector Trainings in the Trans Pecos and Panhandle
Wednesday, November 09, 2016
Chronic Wasting Disease (CWD) Program Standards - Review and Comment By Terry S Singeltary Sr. November 9, 2016
Friday, November 18, 2016
IMPORTANT: SAWCorp CWD Test is NOT APHIS Approved
Thursday, December 08, 2016
TEXAS TAHC confirmed Chronic Wasting Disease (CWD) in a free-ranging elk Dallam County
Saturday, December 03, 2016
*** TEXAS CHRONIC WASTING DISEASE CWD TSE PRION UPDATE 35 CASES TO DATE
FRIDAY, JANUARY 20, 2017 TEXAS TAHC
The Chronic Wasting Disease Rule Proposal Republished for Comment January 20, 2017
SUNDAY, JANUARY 22, 2017
Texas 85th Legislative Session 2017 Chronic Wasting Disease CWD TSE Prion Cervid Captive Breeder Industry
WEDNESDAY, JANUARY 25, 2017
Texas First Case of CWD Detected in Free-Ranging Texas Whitetail Surveillance Zone 3 in Medina County
THURSDAY, JANUARY 26, 2017
Texas CWD Discovered Free-Ranging Whitetail DEER Houston Chronicle Shannon Tompkins PLEASE, CAN YOU HEAR ME NOW?
TITLE: PATHOLOGICAL FEATURES OF CHRONIC WASTING DISEASE IN REINDEER AND DEMONSTRATION OF HORIZONTAL TRANSMISSION
*** DECEMBER 2016 CDC EMERGING INFECTIOUS DISEASE JOURNAL CWD HORIZONTAL TRANSMISSION
*** INFECTIOUS AGENT OF SHEEP SCRAPIE MAY PERSIST IN THE ENVIRONMENT FOR AT LEAST 16 YEARS ***
GUDMUNDUR GEORGSSON1, SIGURDUR SIGURDARSON2 AND PAUL BROWN3
Title: Pathological features of chronic wasting disease in reindeer and demonstration of horizontal transmission
Using in vitro prion replication for high sensitive detection of prions and prionlike proteins and for understanding mechanisms of transmission.
Claudio Soto
Mitchell Center for Alzheimer's diseases and related Brain disorders, Department of Neurology, University of Texas Medical School at Houston.
Prion and prion-like proteins are misfolded protein aggregates with the ability to selfpropagate to spread disease between cells, organs and in some cases across individuals. I n T r a n s m i s s i b l e s p o n g i f o r m encephalopathies (TSEs), prions are mostly composed by a misfolded form of the prion protein (PrPSc), which propagates by transmitting its misfolding to the normal prion protein (PrPC). The availability of a procedure to replicate prions in the laboratory may be important to study the mechanism of prion and prion-like spreading and to develop high sensitive detection of small quantities of misfolded proteins in biological fluids, tissues and environmental samples. Protein Misfolding Cyclic Amplification (PMCA) is a simple, fast and efficient methodology to mimic prion replication in the test tube. PMCA is a platform technology that may enable amplification of any prion-like misfolded protein aggregating through a seeding/nucleation process. In TSEs, PMCA is able to detect the equivalent of one single molecule of infectious PrPSc and propagate prions that maintain high infectivity, strain properties and species specificity. Using PMCA we have been able to detect PrPSc in blood and urine of experimentally infected animals and humans affected by vCJD with high sensitivity and specificity. Recently, we have expanded the principles of PMCA to amplify amyloid-beta (Aβ) and alphasynuclein (α-syn) aggregates implicated in Alzheimer's and Parkinson's diseases, respectively. Experiments are ongoing to study the utility of this technology to detect Aβ and α-syn aggregates in samples of CSF and blood from patients affected by these diseases.
=========================
***Recently, we have been using PMCA to study the role of environmental prion contamination on the horizontal spreading of TSEs. These experiments have focused on the study of the interaction of prions with plants and environmentally relevant surfaces. Our results show that plants (both leaves and roots) bind tightly to prions present in brain extracts and excreta (urine and feces) and retain even small quantities of PrPSc for long periods of time. Strikingly, ingestion of prioncontaminated leaves and roots produced disease with a 100% attack rate and an incubation period not substantially longer than feeding animals directly with scrapie brain homogenate. Furthermore, plants can uptake prions from contaminated soil and transport them to different parts of the plant tissue (stem and leaves). Similarly, prions bind tightly to a variety of environmentally relevant surfaces, including stones, wood, metals, plastic, glass, cement, etc. Prion contaminated surfaces efficiently transmit prion disease when these materials were directly injected into the brain of animals and strikingly when the contaminated surfaces were just placed in the animal cage. These findings demonstrate that environmental materials can efficiently bind infectious prions and act as carriers of infectivity, suggesting that they may play an important role in the horizontal transmission of the disease.
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Since its invention 13 years ago, PMCA has helped to answer fundamental questions of prion propagation and has broad applications in research areas including the food industry, blood bank safety and human and veterinary disease diagnosis.
with CWD TSE Prions, I am not sure there is any absolute yet, other than what we know with transmission studies, and we know tse prion kill, and tse prion are bad. science shows to date, that indeed soil, dirt, some better than others, can act as a carrier. same with objects, farm furniture. take it with how ever many grains of salt you wish, or not. if load factor plays a role in the end formula, then everything should be on the table, in my opinion...tss
Oral Transmissibility of Prion Disease Is Enhanced by Binding to Soil Particles
Author Summary
Transmissible spongiform encephalopathies (TSEs) are a group of incurable neurological diseases likely caused by a misfolded form of the prion protein. TSEs include scrapie in sheep, bovine spongiform encephalopathy (‘‘mad cow’’ disease) in cattle, chronic wasting disease in deer and elk, and Creutzfeldt-Jakob disease in humans. Scrapie and chronic wasting disease are unique among TSEs because they can be transmitted between animals, and the disease agents appear to persist in environments previously inhabited by infected animals. Soil has been hypothesized to act as a reservoir of infectivity and to bind the infectious agent. In the current study, we orally dosed experimental animals with a common clay mineral, montmorillonite, or whole soils laden with infectious prions, and compared the transmissibility to unbound agent. We found that prions bound to montmorillonite and whole soils remained orally infectious, and, in most cases, increased the oral transmission of disease compared to the unbound agent. The results presented in this study suggest that soil may contribute to environmental spread of TSEs by increasing the transmissibility of small amounts of infectious agent in the environment.
tse prion soil
Wednesday, December 16, 2015
Objects in contact with classical scrapie sheep act as a reservoir for scrapie transmission
The sources of dust borne prions are unknown but it seems reasonable to assume that faecal, urine, skin, parturient material and saliva-derived prions may contribute to this mobile environmental reservoir of infectivity. This work highlights a possible transmission route for scrapie within the farm environment, and this is likely to be paralleled in CWD which shows strong similarities with scrapie in terms of prion dissemination and disease transmission. The data indicate that the presence of scrapie prions in dust is likely to make the control of these diseases a considerable challenge.
>>>Particle-associated PrPTSE molecules may migrate from locations of deposition via transport processes affecting soil particles, including entrainment in and movement with air and overland flow. <<<
Fate of Prions in Soil: A Review
Christen B. Smith, Clarissa J. Booth, and Joel A. Pedersen*
Several reports have shown that prions can persist in soil for several years. Significant interest remains in developing methods that could be applied to degrade PrPTSE in naturally contaminated soils. Preliminary research suggests that serine proteases and the microbial consortia in stimulated soils and compost may partially degrade PrPTSE. Transition metal oxides in soil (viz. manganese oxide) may also mediate prion inactivation. Overall, the effect of prion attachment to soil particles on its persistence in the environment is not well understood, and additional study is needed to determine its implications on the environmental transmission of scrapie and CWD.
P.161: Prion soil binding may explain efficient horizontal CWD transmission
Conclusion. Silty clay loam exhibits highly efficient prion binding, inferring a durable environmental reservoir, and an efficient mechanism for indirect horizontal CWD transmission.
>>>Another alternative would be an absolute prohibition on the movement of deer within the state for any purpose. While this alternative would significantly reduce the potential spread of CWD, it would also have the simultaneous effect of preventing landowners and land managers from implementing popular management strategies involving the movement of deer, and would deprive deer breeders of the ability to engage in the business of buying and selling breeder deer. Therefore, this alternative was rejected because the department determined that it placed an avoidable burden on the regulated community.<<<
Wednesday, December 16, 2015
Objects in contact with classical scrapie sheep act as a reservoir for scrapie transmission
Timm Konold1*, Stephen A. C. Hawkins2, Lisa C. Thurston3, Ben C. Maddison4, Kevin C. Gough5, Anthony Duarte1 and Hugh A. Simmons1
1 Animal Sciences Unit, Animal and Plant Health Agency Weybridge, Addlestone, UK, 2 Pathology Department, Animal and Plant Health Agency Weybridge, Addlestone, UK, 3 Surveillance and Laboratory Services, Animal and Plant Health Agency Penrith, Penrith, UK, 4 ADAS UK, School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington, UK, 5 School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington, UK
Classical scrapie is an environmentally transmissible prion disease of sheep and goats. Prions can persist and remain potentially infectious in the environment for many years and thus pose a risk of infecting animals after re-stocking. In vitro studies using serial protein misfolding cyclic amplification (sPMCA) have suggested that objects on a scrapie affected sheep farm could contribute to disease transmission. This in vivo study aimed to determine the role of field furniture (water troughs, feeding troughs, fencing, and other objects that sheep may rub against) used by a scrapie-infected sheep flock as a vector for disease transmission to scrapie-free lambs with the prion protein genotype VRQ/VRQ, which is associated with high susceptibility to classical scrapie. When the field furniture was placed in clean accommodation, sheep became infected when exposed to either a water trough (four out of five) or to objects used for rubbing (four out of seven). This field furniture had been used by the scrapie-infected flock 8 weeks earlier and had previously been shown to harbor scrapie prions by sPMCA. Sheep also became infected (20 out of 23) through exposure to contaminated field furniture placed within pasture not used by scrapie-infected sheep for 40 months, even though swabs from this furniture tested negative by PMCA. This infection rate decreased (1 out of 12) on the same paddock after replacement with clean field furniture. Twelve grazing sheep exposed to field furniture not in contact with scrapie-infected sheep for 18 months remained scrapie free. The findings of this study highlight the role of field furniture used by scrapie-infected sheep to act as a reservoir for disease re-introduction although infectivity declines considerably if the field furniture has not been in contact with scrapie-infected sheep for several months. PMCA may not be as sensitive as VRQ/VRQ sheep to test for environmental contamination.
snip...
Discussion
Classical scrapie is an environmentally transmissible disease because it has been reported in naïve, supposedly previously unexposed sheep placed in pastures formerly occupied by scrapie-infected sheep (4, 19, 20). Although the vector for disease transmission is not known, soil is likely to be an important reservoir for prions (2) where – based on studies in rodents – prions can adhere to minerals as a biologically active form (21) and remain infectious for more than 2 years (22). Similarly, chronic wasting disease (CWD) has re-occurred in mule deer housed in paddocks used by infected deer 2 years earlier, which was assumed to be through foraging and soil consumption (23).
Our study suggested that the risk of acquiring scrapie infection was greater through exposure to contaminated wooden, plastic, and metal surfaces via water or food troughs, fencing, and hurdles than through grazing. Drinking from a water trough used by the scrapie flock was sufficient to cause infection in sheep in a clean building. Exposure to fences and other objects used for rubbing also led to infection, which supported the hypothesis that skin may be a vector for disease transmission (9). The risk of these objects to cause infection was further demonstrated when 87% of 23 sheep presented with PrPSc in lymphoid tissue after grazing on one of the paddocks, which contained metal hurdles, a metal lamb creep and a water trough in contact with the scrapie flock up to 8 weeks earlier, whereas no infection had been demonstrated previously in sheep grazing on this paddock, when equipped with new fencing and field furniture. When the contaminated furniture and fencing were removed, the infection rate dropped significantly to 8% of 12 sheep, with soil of the paddock as the most likely source of infection caused by shedding of prions from the scrapie-infected sheep in this paddock up to a week earlier.
This study also indicated that the level of contamination of field furniture sufficient to cause infection was dependent on two factors: stage of incubation period and time of last use by scrapie-infected sheep. Drinking from a water trough that had been used by scrapie sheep in the predominantly pre-clinical phase did not appear to cause infection, whereas infection was shown in sheep drinking from the water trough used by scrapie sheep in the later stage of the disease. It is possible that contamination occurred through shedding of prions in saliva, which may have contaminated the surface of the water trough and subsequently the water when it was refilled. Contamination appeared to be sufficient to cause infection only if the trough was in contact with sheep that included clinical cases. Indeed, there is an increased risk of bodily fluid infectivity with disease progression in scrapie (24) and CWD (25) based on PrPSc detection by sPMCA. Although ultraviolet light and heat under natural conditions do not inactivate prions (26), furniture in contact with the scrapie flock, which was assumed to be sufficiently contaminated to cause infection, did not act as vector for disease if not used for 18 months, which suggest that the weathering process alone was sufficient to inactivate prions.
PrPSc detection by sPMCA is increasingly used as a surrogate for infectivity measurements by bioassay in sheep or mice. In this reported study, however, the levels of PrPSc present in the environment were below the limit of detection of the sPMCA method, yet were still sufficient to cause infection of in-contact animals. In the present study, the outdoor objects were removed from the infected flock 8 weeks prior to sampling and were positive by sPMCA at very low levels (2 out of 37 reactions). As this sPMCA assay also yielded 2 positive reactions out of 139 in samples from the scrapie-free farm, the sPMCA assay could not detect PrPSc on any of the objects above the background of the assay. False positive reactions with sPMCA at a low frequency associated with de novo formation of infectious prions have been reported (27, 28). This is in contrast to our previous study where we demonstrated that outdoor objects that had been in contact with the scrapie-infected flock up to 20 days prior to sampling harbored PrPSc that was detectable by sPMCA analysis [4 out of 15 reactions (12)] and was significantly more positive by the assay compared to analogous samples from the scrapie-free farm. This discrepancy could be due to the use of a different sPMCA substrate between the studies that may alter the efficiency of amplification of the environmental PrPSc. In addition, the present study had a longer timeframe between the objects being in contact with the infected flock and sampling, which may affect the levels of extractable PrPSc. Alternatively, there may be potentially patchy contamination of this furniture with PrPSc, which may have been missed by swabbing. The failure of sPMCA to detect CWD-associated PrP in saliva from clinically affected deer despite confirmation of infectivity in saliva-inoculated transgenic mice was associated with as yet unidentified inhibitors in saliva (29), and it is possible that the sensitivity of sPMCA is affected by other substances in the tested material. In addition, sampling of amplifiable PrPSc and subsequent detection by sPMCA may be more difficult from furniture exposed to weather, which is supported by the observation that PrPSc was detected by sPMCA more frequently in indoor than outdoor furniture (12). A recent experimental study has demonstrated that repeated cycles of drying and wetting of prion-contaminated soil, equivalent to what is expected under natural weathering conditions, could reduce PMCA amplification efficiency and extend the incubation period in hamsters inoculated with soil samples (30). This seems to apply also to this study even though the reduction in infectivity was more dramatic in the sPMCA assays than in the sheep model. Sheep were not kept until clinical end-point, which would have enabled us to compare incubation periods, but the lack of infection in sheep exposed to furniture that had not been in contact with scrapie sheep for a longer time period supports the hypothesis that prion degradation and subsequent loss of infectivity occurs even under natural conditions.
In conclusion, the results in the current study indicate that removal of furniture that had been in contact with scrapie-infected animals should be recommended, particularly since cleaning and decontamination may not effectively remove scrapie infectivity (31), even though infectivity declines considerably if the pasture and the field furniture have not been in contact with scrapie-infected sheep for several months. As sPMCA failed to detect PrPSc in furniture that was subjected to weathering, even though exposure led to infection in sheep, this method may not always be reliable in predicting the risk of scrapie infection through environmental contamination. These results suggest that the VRQ/VRQ sheep model may be more sensitive than sPMCA for the detection of environmentally associated scrapie, and suggest that extremely low levels of scrapie contamination are able to cause infection in susceptible sheep genotypes.
Keywords: classical scrapie, prion, transmissible spongiform encephalopathy, sheep, field furniture, reservoir, serial protein misfolding cyclic amplification
Wednesday, December 16, 2015
*** Objects in contact with classical scrapie sheep act as a reservoir for scrapie transmission ***
*** Infectious agent of sheep scrapie may persist in the environment for at least 16 years ***
Gudmundur Georgsson1, Sigurdur Sigurdarson2 and Paul Brown3
***at present, no cervid PrP allele conferring absolute resistance to prion infection has been identified.
P-145 Estimating chronic wasting disease resistance in cervids using real time quaking- induced conversion
Nicholas J Haley1, Rachel Rielinqer2, Kristen A Davenport3, W. David Walter4, Katherine I O'Rourke5, Gordon Mitchell6, Juergen A Richt2
1 Department of Microbiology and Immunology, Midwestern University, United States; 2Department of Diagnostic Medicine and Pathobiology, Kansas State University; 3Prion Research Center; Colorado State University; 4U.S. Geological Survey, Pennsylvania Cooperative Fish and Wildlife Research Unit; 5Agricultural Research Service, United States Department of Agriculture; 6Canadian Food Inspection Agency, National and OlE Reference Laboratory for Scrapie and CWO
In mammalian species, the susceptibility to prion diseases is affected, in part, by the sequence of the host's prion protein (PrP). In sheep, a gradation from scrapie susceptible to resistant has been established both in vivo and in vitro based on the amino acids present at PrP positions 136, 154, and 171, which has led to global breeding programs to reduce the prevalence of scrapie in domestic sheep. In cervids, resistance is commonly characterized as a delayed progression of chronic wasting disease (CWD); at present, no cervid PrP allele conferring absolute resistance to prion infection has been identified. To model the susceptibility of various naturally-occurring and hypothetical cervid PrP alleles in vitro, we compared the amplification rates and efficiency of various CWD isolates in recombinant PrPC using real time quaking-induced conversion. We hypothesized that amplification metrics of these isolates in cervid PrP substrates would correlate to in vivo susceptibility - allowing susceptibility prediction for alleles found at 10 frequency in nature, and that there would be an additive effect of multiple resistant codons in hypothetical alleles. Our studies demonstrate that in vitro amplification metrics predict in vivo susceptibility, and that alleles with multiple codons, each influencing resistance independently, do not necessarily contribute additively to resistance. Importantly, we found that the white-tailed deer 226K substrate exhibited the slowest amplification rate among those evaluated, suggesting that further investigation of this allele and its resistance in vivo are warranted to determine if absolute resistance to CWD is possible.
***at present, no cervid PrP allele conferring absolute resistance to prion infection has been identified.
PRION 2016 CONFERENCE TOKYO
Pathways of Prion Spread during Early Chronic Wasting Disease in Deer
Clare E. Hoover1, Kristen A. Davenport1, Davin M. Henderson1,Nathaniel D. Denkers1, Candace K. Mathiason1, Claudio Soto2, Mark D. Zabel1and Edward A. Hoover1# +Author Affiliations
1Prion Research Center, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, USA 2Mitchell Center for Alzheimer's Disease and Related Brain Disorders, Department of Neurology, University of Texas, Houston, Texas, USA ABSTRACT
Among prion infections, two scenarios of prion spread are generally observed: (a) early lymphoid tissue replication or (b) direct neuroinvasion without substantial antecedent lymphoid amplification. In nature, cervids are infected with chronic wasting disease (CWD) prions by oral and nasal mucosal exposure, and studies of early CWD pathogenesis have implicated pharyngeal lymphoid tissue as the earliest sites of prion accumulation. However, knowledge of chronological events in prion spread during early infection remains incomplete. To investigate this knowledge gap in early CWD pathogenesis, we exposed white-tailed deer to CWD prions by mucosal routes and performed serial necropsies to assess PrPCWD tissue distribution by real-time quaking-induced conversion (RT-QuIC) and tyramide signal amplification immunohistochemistry (TSA-IHC). Although PrPCWD was not detected by either method in the initial days (1 and 3) post-exposure, we observed PrPCWD seeding activity and follicular immunoreactivity in oropharyngeal lymphoid tissues at 1 and 2 months post-exposure (MPE). At 3 MPE, PrPCWD replication had expanded to all systemic lymphoid tissues. By 4 MPE, the PrPCWD burden in all lymphoid tissues had increased, and approached levels observed in terminal disease, yet there was no evidence of nervous system invasion. These results indicate the first site of CWD prion entry is in the oropharynx and the initial phase of prion amplification occurs in the oropharyngeal lymphoid tissues followed by rapid dissemination to systemic lymphoid tissues. This lymphoid replication phase appears to precede neuroinvasion.
IMPORTANCE Chronic wasting disease (CWD) is a universally fatal transmissible spongiform encephalopathy affecting cervids and natural infection occurs through oral and nasal mucosal exposure to infectious prions. Terminal disease is characterized by PrPCWD accumulation in the brain and lymphoid tissues of affected animals. However, the initial sites of prion accumulation and pathways of prion spread during early CWD infection remain unknown. To investigate the chronological events of early prion pathogenesis, we exposed deer to CWD prions and monitored the tissue distribution of PrPCWD over the first 4 months of infection. We show CWD uptake occurs in the oropharynx with initial prion replication in the draining oropharyngeal lymphoid tissues, rapidly followed by dissemination to systemic lymphoid tissues without evidence of neuroinvasion. This data highlights the two phases of CWD infection: a robust prion amplification in systemic lymphoid tissues prior to neuroinvasion or establishment of a carrier state.
FOOTNOTES
↵#Address correspondence to Edward A. Hoover, edward.hoover@colostate.edu Copyright © 2017 American Society for Microbiology. All Rights Reserved.
TUESDAY, MARCH 28, 2017
Passage of scrapie to deer results in a new phenotype upon return passage to sheep
THURSDAY, MARCH 30, 2017
Norway CWD Skrantesjuke: VKM report supports the National Veterinary Institute perception management
MONDAY, MARCH 27, 2017
Wyoming CWD Postive Mule Deer Doe Near Pinedale
MONDAY, MARCH 20, 2017
Wisconsin CWD TSE Prion Annual Roundup 441 positive
TUESDAY, MARCH 14, 2017
Iowa 12 deer test positive for chronic wasting disease from 2016-17 hunting seasons
MONDAY, MARCH 13, 2017
CHRONIC WASTING DISEASE CWD TSE PRION UDATE March 13, 2017
FRIDAY, MARCH 10, 2017
Nebraska Tests confirm spread of CWD to Lancaster County
THURSDAY, MARCH 09, 2017
Missouri MDC REPORTS TWO CASES OF CWD IN ST. CLAIR COUNTY
WEDNESDAY, MARCH 01, 2017
South central Pennsylvania Captive Deer Tests Positive for Chronic Wasting Disease
SATURDAY, MARCH 04, 2017
Maryland DNR Six Deer Test Positive for Chronic Wasting Disease
FRIDAY, JANUARY 27, 2017
TEXAS, Politicians, TAHC, TPWD, and the spread of CWD TSE Prion in Texas
SATURDAY, JANUARY 14, 2017
CHRONIC WASTING DISEASE CWD TSE PRION GLOBAL UPDATE JANUARY 14, 2017
From: TSS (216-119-163-189.ipset45.wt.net)
Subject: CWD aka MAD DEER/ELK TO HUMANS ???
Date: September 30, 2002 at 7:06 am PST
From: "Belay, Ermias"
To: Cc: "Race, Richard (NIH)" ; ; "Belay, Ermias"
Sent: Monday, September 30, 2002 9:22 AM
Subject: RE: TO CDC AND NIH - PUB MED- 3 MORE DEATHS - CWD - YOUNG HUNTERS
Dear Sir/Madam,
In the Archives of Neurology you quoted (the abstract of which was attached to your email), we did not say CWD in humans will present like variant CJD. That assumption would be wrong. I encourage you to read the whole article and call me if you have questions or need more clarification (phone: 404-639-3091). Also, we do not claim that "no-one has ever been infected with prion disease from eating venison." Our conclusion stating that we found no strong evidence of CWD transmission to humans in the article you quoted or in any other forum is limited to the patients we investigated.
Ermias Belay, M.D. Centers for Disease Control and Prevention
-----Original Message-----
From: Sent: Sunday, September 29, 2002 10:15 AM
Subject: TO CDC AND NIH - PUB MED- 3 MORE DEATHS - CWD - YOUNG HUNTERS
Sunday, November 10, 2002 6:26 PM ......snip........end..............TSS
Thursday, April 03, 2008
A prion disease of cervids: Chronic wasting disease 2008 1: Vet Res. 2008 Apr 3;39(4):41 A prion
disease of cervids: Chronic wasting disease Sigurdson CJ.
snip...
*** twenty-seven CJD patients who regularly consumed venison were reported to the Surveillance Center***,
snip... full text ;
CJD is so rare in people under age 30, one case in a billion (leaving out medical mishaps), that four cases under 30 is "very high," says Colorado neurologist Bosque. "Then, if you add these other two from Wisconsin [cases in the newspaper], six cases of CJD in people associated with venison is very, very high." Only now, with Mary Riley, there are at least seven, and possibly eight, with Steve, her dining companion. "It's not critical mass that matters," however, Belay says. "One case would do it for me." The chance that two people who know each other would both contact CJD, like the two Wisconsin sportsmen, is so unlikely, experts say, it would happen only once in 140 years.
Given the incubation period for TSEs in humans, it may require another generation to write the final chapter on CWD in Wisconsin. "Does chronic wasting disease pass into humans? We'll be able to answer that in 2022," says Race. Meanwhile, the state has become part of an immense experiment.
I urge everyone to watch this video closely...terry
*** you can see video here and interview with Jeff's Mom, and scientist telling you to test everything and potential risk factors for humans ***
PRION2016 CONFERENCE TOKYO UPDATED SCIENCE ON ZOONOSIS
*** The potential impact of prion diseases on human health was greatly magnified by the recognition that interspecies transfer of BSE to humans by beef ingestion resulted in vCJD. While changes in animal feed constituents and slaughter practices appear to have curtailed vCJD, there is concern that CWD of free-ranging deer and elk in the U.S. might also cross the species barrier. Thus, consuming venison could be a source of human prion disease. Whether BSE and CWD represent interspecies scrapie transfer or are newly arisen prion diseases is unknown. Therefore, the possibility of transmission of prion disease through other food animals cannot be ruled out. There is evidence that vCJD can be transmitted through blood transfusion. There is likely a pool of unknown size of asymptomatic individuals infected with vCJD, and there may be asymptomatic individuals infected with the CWD equivalent. These circumstances represent a potential threat to blood, blood products, and plasma supplies.
***********CJD REPORT 1994 increased risk for consumption of veal and venison and lamb***********
CREUTZFELDT JAKOB DISEASE SURVEILLANCE IN THE UNITED KINGDOM THIRD ANNUAL REPORT AUGUST 1994
Consumption of venison and veal was much less widespread among both cases and controls. For both of these meats there was evidence of a trend with increasing frequency of consumption being associated with increasing risk of CJD. (not nvCJD, but sporadic CJD...tss)
These associations were largely unchanged when attention was restricted to pairs with data obtained from relatives. ...
Table 9 presents the results of an analysis of these data.
There is STRONG evidence of an association between ‘’regular’’ veal eating and risk of CJD (p = .0.01).
Individuals reported to eat veal on average at least once a year appear to be at 13 TIMES THE RISK of individuals who have never eaten veal.
There is, however, a very wide confidence interval around this estimate. There is no strong evidence that eating veal less than once per year is associated with increased risk of CJD (p = 0.51).
The association between venison eating and risk of CJD shows similar pattern, with regular venison eating associated with a 9 FOLD INCREASE IN RISK OF CJD (p = 0.04).
There is some evidence that risk of CJD INCREASES WITH INCREASING FREQUENCY OF LAMB EATING (p = 0.02).
The evidence for such an association between beef eating and CJD is weaker (p = 0.14). When only controls for whom a relative was interviewed are included, this evidence becomes a little STRONGER (p = 0.08).
snip...
It was found that when veal was included in the model with another exposure, the association between veal and CJD remained statistically significant (p = < 0.05 for all exposures), while the other exposures ceased to be statistically significant (p = > 0.05).
snip...
In conclusion, an analysis of dietary histories revealed statistical associations between various meats/animal products and INCREASED RISK OF CJD. When some account was taken of possible confounding, the association between VEAL EATING AND RISK OF CJD EMERGED AS THE STRONGEST OF THESE ASSOCIATIONS STATISTICALLY. ...
snip...
In the study in the USA, a range of foodstuffs were associated with an increased risk of CJD, including liver consumption which was associated with an apparent SIX-FOLD INCREASE IN THE RISK OF CJD. By comparing the data from 3 studies in relation to this particular dietary factor, the risk of liver consumption became non-significant with an odds ratio of 1.2 (PERSONAL COMMUNICATION, PROFESSOR A. HOFMAN. ERASMUS UNIVERSITY, ROTTERDAM). (???...TSS)
snip...see full report ;
CJD9/10022
October 1994
Mr R.N. Elmhirst Chairman British Deer Farmers Association Holly Lodge Spencers Lane BerksWell Coventry CV7 7BZ
Dear Mr Elmhirst,
CREUTZFELDT-JAKOB DISEASE (CJD) SURVEILLANCE UNIT REPORT
Thank you for your recent letter concerning the publication of the third annual report from the CJD Surveillance Unit. I am sorry that you are dissatisfied with the way in which this report was published.
The Surveillance Unit is a completely independant outside body and the Department of Health is committed to publishing their reports as soon as they become available. In the circumstances it is not the practice to circulate the report for comment since the findings of the report would not be amended. In future we can ensure that the British Deer Farmers Association receives a copy of the report in advance of publication.
The Chief Medical Officer has undertaken to keep the public fully informed of the results of any research in respect of CJD. This report was entirely the work of the unit and was produced completely independantly of the the Department.
The statistical results reqarding the consumption of venison was put into perspective in the body of the report and was not mentioned at all in the press release. Media attention regarding this report was low key but gave a realistic presentation of the statistical findings of the Unit. This approach to publication was successful in that consumption of venison was highlighted only once by the media ie. in the News at one television proqramme.
I believe that a further statement about the report, or indeed statistical links between CJD and consumption of venison, would increase, and quite possibly give damaging credence, to the whole issue. From the low key media reports of which I am aware it seems unlikely that venison consumption will suffer adversely, if at all.
http://web.archive.org/web/20030511010117/http://www.bseinquiry.gov.uk/files/yb/1994/10/00003001.pdf
CHRONIC WASTING DISEASE CWD AND SCRAPIE TSE PRION ZOONOSIS UPDATE
*** WDA 2016 NEW YORK ***
We found that CWD adapts to a new host more readily than BSE and that human PrP was unexpectedly prone to misfolding by CWD prions. In addition, we investigated the role of specific regions of the bovine, deer and human PrP protein in resistance to conversion by prions from another species. We have concluded that the human protein has a region that confers unusual susceptibility to conversion by CWD prions.
Student Presentations Session 2
The species barriers and public health threat of CWD and BSE prions
Ms. Kristen Davenport1, Dr. Davin Henderson1, Dr. Candace Mathiason1, Dr. Edward Hoover1 1Colorado State University
Chronic wasting disease (CWD) is spreading rapidly through cervid populations in the USA. Bovine spongiform encephalopathy (BSE, mad cow disease) arose in the 1980s because cattle were fed recycled animal protein. These and other prion diseases are caused by abnormal folding of the normal prion protein (PrP) into a disease causing form (PrPd), which is pathogenic to nervous system cells and can cause subsequent PrP to misfold. CWD spreads among cervids very efficiently, but it has not yet infected humans. On the other hand, BSE was spread only when cattle consumed infected bovine or ovine tissue, but did infect humans and other species. The objective of this research is to understand the role of PrP structure in cross-species infection by CWD and BSE. To study the propensity of each species’ PrP to be induced to misfold by the presence of PrPd from verious species, we have used an in vitro system that permits detection of PrPd in real-time. We measured the conversion efficiency of various combinations of PrPd seeds and PrP substrate combinations. We observed the cross-species behavior of CWD and BSE, in addition to feline-adapted CWD and BSE. We found that CWD adapts to a new host more readily than BSE and that human PrP was unexpectedly prone to misfolding by CWD prions. In addition, we investigated the role of specific regions of the bovine, deer and human PrP protein in resistance to conversion by prions from another species. We have concluded that the human protein has a region that confers unusual susceptibility to conversion by CWD prions. CWD is unique among prion diseases in its rapid spread in natural populations. BSE prions are essentially unaltered upon passage to a new species, while CWD adapts to the new species. This adaptation has consequences for surveillance of humans exposed to CWD.
Wildlife Disease Risk Communication Research Contributes to Wildlife Trust Administration Exploring perceptions about chronic wasting disease risks among wildlife and agriculture professionals and stakeholders
PRION 2016 TOKYO
Zoonotic Potential of CWD Prions: An Update
Chronic wasting disease (CWD) is a widespread and highly transmissible prion disease in free-ranging and captive cervid species in North America. The zoonotic potential of CWD prions is a serious public health concern, but the susceptibility of human CNS and peripheral organs to CWD prions remains largely unresolved. We reported earlier that peripheral and CNS infections were detected in transgenic mice expressing human PrP129M or PrP129V. Here we will present an update on this project, including evidence for strain dependence and influence of cervid PrP polymorphisms on CWD zoonosis as well as the characteristics of experimental human CWD prions.
PRION 2016 TOKYO In Conjunction with Asia Pacific Prion Symposium 2016 PRION 2016 Tokyo Prion 2016
Cervid to human prion transmission
Kong, Qingzhong
Case Western Reserve University, Cleveland, OH, United States
Abstract
Prion disease is transmissible and invariably fatal. Chronic wasting disease (CWD) is the prion disease affecting deer, elk and moose, and it is a widespread and expanding epidemic affecting 22 US States and 2 Canadian provinces so far. CWD poses the most serious zoonotic prion transmission risks in North America because of huge venison consumption (>6 million deer/elk hunted and consumed annually in the USA alone), significant prion infectivity in muscles and other tissues/fluids from CWD-affected cervids, and usually high levels of individual exposure to CWD resulting from consumption of the affected animal among often just family and friends. However, we still do not know whether CWD prions can infect humans in the brain or peripheral tissues or whether clinical/asymptomatic CWD zoonosis has already occurred, and we have no essays to reliably detect CWD infection in humans. We hypothesize that:
(1) The classic CWD prion strain can infect humans at low levels in the brain and peripheral lymphoid tissues;
(2) The cervid-to-human transmission barrier is dependent on the cervid prion strain and influenced by the host (human) prion protein (PrP) primary sequence;
(3) Reliable essays can be established to detect CWD infection in humans;and
(4) CWD transmission to humans has already occurred. We will test these hypotheses in 4 Aims using transgenic (Tg) mouse models and complementary in vitro approaches.
Aim 1 will prove that the classical CWD strain may infect humans in brain or peripheral lymphoid tissues at low levels by conducting systemic bioassays in a set of "humanized" Tg mouse lines expressing common human PrP variants using a number of CWD isolates at varying doses and routes. Experimental "human CWD" samples will also be generated for Aim 3.
Aim 2 will test the hypothesis that the cervid-to-human prion transmission barrier is dependent on prion strain and influenced by the host (human) PrP sequence by examining and comparing the transmission efficiency and phenotypes of several atypical/unusual CWD isolates/strains as well as a few prion strains from other species that have adapted to cervid PrP sequence, utilizing the same panel of humanized Tg mouse lines as in Aim 1.
Aim 3 will establish reliable essays for detection and surveillance of CWD infection in humans by examining in details the clinical, pathological, biochemical and in vitro seeding properties of existing and future experimental "human CWD" samples generated from Aims 1-2 and compare them with those of common sporadic human Creutzfeldt-Jakob disease (sCJD) prions.
Aim 4 will attempt to detect clinical CWD-affected human cases by examining a significant number of brain samples from prion-affected human subjects in the USA and Canada who have consumed venison from CWD-endemic areas utilizing the criteria and essays established in Aim 3. The findings from this proposal will greatly advance our understandings on the potential and characteristics of cervid prion transmission in humans, establish reliable essays for CWD zoonosis and potentially discover the first case(s) of CWD infection in humans.
Public Health Relevance There are significant and increasing human exposure to cervid prions because chronic wasting disease (CWD, a widespread and highly infectious prion disease among deer and elk in North America) continues spreading and consumption of venison remains popular, but our understanding on cervid-to-human prion transmission is still very limited, raising public health concerns. This proposal aims to define the zoonotic risks of cervid prions and set up and apply essays to detect CWD zoonosis using mouse models and in vitro methods. The findings will greatly expand our knowledge on the potentials and characteristics of cervid prion transmission in humans, establish reliable essays for such infections and may discover the first case(s) of CWD infection in humans.
Key Molecular Mechanisms of TSEs
Zabel, Mark D.
Colorado State University-Fort Collins, Fort Collins, CO, United States Abstract Prion diseases, or transmissible spongiform encephalopathies (TSEs), are fatal neurodegenerative diseases affecting humans, cervids, bovids, and ovids. The absolute requirement of PrPC expression to generate prion diseases and the lack of instructional nucleic acid define prions as unique infectious agents. Prions exhibit species-specific tropism, inferring that unique prion strains exist that preferentially infct certain host species and confront transmission barriers to heterologous host species. However, transmission barriers are not absolute. Scientific consensus agrees that the sheep TSE scrapie probably breached the transmission barrier to cattle causing bovine spongiform encephalopathy that subsequently breached the human transmission barrier and likely caused several hundred deaths by a new-variant form of the human TSE Creutzfeldt-Jakob disease in the UK and Europe. The impact to human health, emotion and economies can still be felt in areas like farming, blood and organ donations and the threat of a latent TSE epidemic. This precedent raises the real possibility of other TSEs, like chronic wasting disease of cervids, overcoming similar human transmission barriers. A groundbreaking discovery made last year revealed that mice infected with heterologous prion strains facing significant transmission barriers replicated prions far more readily in spleens than brains6. Furthermore, these splenic prions exhibited weakened transmission barriers and expanded host ranges compared to neurogenic prions. These data question conventional wisdom of avoiding neural tissue to avoid prion xenotransmission, when more promiscuous prions may lurk in extraneural tissues. Data derived from work previously funded by NIH demonstrate that Complement receptors CD21/35 bind prions and high density PrPC and differentially impact prion disease depending on the prion isolate or strain used. Recent advances in live animal and whole organ imaging have led us to generate preliminary data to support novel, innovative approaches to assessing prion capture and transport. We plan to test our unifying hypothesis for this proposal that CD21/35 control the processes of peripheral prion capture, transport, strain selection and xenotransmission in the following specific aims. 1. Assess the role of CD21/35 in splenic prion strain selection and host range expansion. 2. Determine whether CD21/35 and C1q differentially bind distinct prion strains 3. Monitor the effects of CD21/35 on prion trafficking in real time and space 4. Assess the role of CD21/35 in incunabular prion trafficking
Public Health Relevance Transmissible spongiform encephalopathies, or prion diseases, are devastating illnesses that greatly impact public health, agriculture and wildlife in North America and around the world. The impact to human health, emotion and economies can still be felt in areas like farming, blood and organ donations and the threat of a latent TSE epidemic. This precedent raises the real possibility of other TSEs, like chronic wasting disease (CWD) of cervids, overcoming similar human transmission barriers. Early this year Canada reported its first case of BSE in over a decade audits first case of CWD in farmed elk in three years, underscoring the need for continued vigilance and research. Identifying mechanisms of transmission and zoonoses remains an extremely important and intense area of research that will benefit human and other animal populations.
PMCA Detection of CWD Infection in Cervid and Non-Cervid Species
Hoover, Edward Arthur
Colorado State University-Fort Collins, Fort Collins, CO, United States
LOOKING FOR CWD IN HUMANS AS nvCJD or as an ATYPICAL CJD, LOOKING IN ALL THE WRONG PLACES $$$
*** These results would seem to suggest that CWD does indeed have zoonotic potential, at least as judged by the compatibility of CWD prions and their human PrPC target. Furthermore, extrapolation from this simple in vitro assay suggests that if zoonotic CWD occurred, it would most likely effect those of the PRNP codon 129-MM genotype and that the PrPres type would be similar to that found in the most common subtype of sCJD (MM1).***
Monday, May 02, 2016
*** Zoonotic Potential of CWD Prions: An Update Prion 2016 Tokyo ***
*** We recently observed the direct transmission of a natural classical scrapie isolate to macaque after a 10-year silent incubation period,
***with features similar to some reported for human cases of sporadic CJD, albeit requiring fourfold long incubation than BSE. Scrapie, as recently evoked in humanized mice (Cassard, 2014),
***is the third potentially zoonotic PD (with BSE and L-type BSE),
***thus questioning the origin of human sporadic cases. We will present an updated panorama of our different transmission studies and discuss the implications of such extended incubation periods on risk assessment of animal PD for human health.
***thus questioning the origin of human sporadic cases***
***our findings suggest that possible transmission risk of H-type BSE to sheep and human. Bioassay will be required to determine whether the PMCA products are infectious to these animals.
*** In complement to the recent demonstration that humanized mice are susceptible to scrapie, we report here the first observation of direct transmission of a natural classical scrapie isolate to a macaque after a 10-year incubation period. Neuropathologic examination revealed all of the features of a prion disease: spongiform change, neuronal loss, and accumulation of PrPres throughout the CNS.
*** This observation strengthens the questioning of the harmlessness of scrapie to humans, at a time when protective measures for human and animal health are being dismantled and reduced as c-BSE is considered controlled and being eradicated.
*** Our results underscore the importance of precautionary and protective measures and the necessity for long-term experimental transmission studies to assess the zoonotic potential of other animal prion strains.
why do we not want to do TSE transmission studies on chimpanzees $
5. A positive result from a chimpanzee challenged severly would likely create alarm in some circles even if the result could not be interpreted for man. I have a view that all these agents could be transmitted provided a large enough dose by appropriate routes was given and the animals kept long enough. Until the mechanisms of the species barrier are more clearly understood it might be best to retain that hypothesis.
snip...
R. BRADLEY
Transmission Studies
Mule deer transmissions of CWD were by intracerebral inoculation and compared with natural cases {the following was written but with a single line marked through it ''first passage (by this route)}...TSS
resulted in a more rapidly progressive clinical disease with repeated episodes of synocopy ending in coma. One control animal became affected, it is believed through contamination of inoculum (?saline). Further CWD transmissions were carried out by Dick Marsh into ferret, mink and squirrel monkey. Transmission occurred in ALL of these species with the shortest incubation period in the ferret.
snip...
Spongiform Encephalopathy in Captive Wild ZOO BSE INQUIRY
”The occurrence of CWD must be viewed against the contest of the locations in which it occurred. It was an incidental and unwelcome complication of the respective wildlife research programmes. Despite it’s subsequent recognition as a new disease of cervids, therefore justifying direct investigation, no specific research funding was forthcoming. The USDA veiwed it as a wildlife problem and consequently not their province!” page 26.
We inoculated cynomolgus macaques with serial dilutions of BSE-infected material. High dose-inoculated animals developed typical clinical disease with all the pathognomonic hallmarks, and incubation periods ranging from 3–8 years. Among low-dosed animals, some developed clinical signs with atypical patterns after extensive incubation periods, exhibiting lesion and biochemical profiles that differed sharply from the typical disease picture. Despite the presence of neurological signs and neuronal lesions, classical lesions of spongiosis and presence of cerebral PrPres were inconstant, or even absent. These observations suggest that low-dose exposure, which would have been the most frequent occurrence during the period of risk, could induce a non-typical pathology that may not be recognized as "prion disease."
link url not available, please see PRION 2011 ;
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Terry S. Singeltary Sr.
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