Switch to Standard View
Grass Plants Bind, Retain, Uptake, and Transport Infectious Prions
Sandra Pritzkow, Rodrigo Morales , Fabio Moda 3, Uffaf Khan, Glenn C. Telling, Edward Hoover, Claudio Soto
email 3Present address: IRCCS Foundation Carlo Besta Neurological Institute, 20133 Milan, Italy
Publication stage: In Press Corrected Proof
•Grass plants bind prions from contaminated brain and excreta •Prions from different strains and species remain bound to living plants •Hamsters fed with prion-contaminated plant samples develop prion disease •Stems and leaves from grass plants grown in infected soil contain prions
Prions are the protein-based infectious agents responsible for prion diseases. Environmental prion contamination has been implicated in disease transmission. Here, we analyzed the binding and retention of infectious prion protein (PrPSc) to plants. Small quantities of PrPSc contained in diluted brain homogenate or in excretory materials (urine and feces) can bind to wheat grass roots and leaves. Wild-type hamsters were efficiently infected by ingestion of prion-contaminated plants. The prion-plant interaction occurs with prions from diverse origins, including chronic wasting disease. Furthermore, leaves contaminated by spraying with a prion-containing preparation retained PrPSc for several weeks in the living plant. Finally, plants can uptake prions from contaminated soil and transport them to aerial parts of the plant (stem and leaves). These findings demonstrate that plants can efficiently bind infectious prions and act as carriers of infectivity, suggesting a possible role of environmental prion contamination in the horizontal transmission of the disease.
This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
Received: October 31, 2014; Received in revised form: February 4, 2015; Accepted: April 15, 2015; Published Online: May 14, 2015
© 2015 The Authors. Published by Elsevier Inc.
Prions Bind to Plants and Bound-PrPSc Efficiently Sustain Prion Replication
To study whether plants can interact with prions, we exposed wheat grass roots and leaves to brain homogenate from hamsters that have succumbed to prion disease induced by experimental inoculation with the 263K prion strain. The presence of PrPSc and infectivity attached to the plants was studied in vitro using the protein misfolding cyclic amplification (PMCA) technique and in vivo by infectivity bioassays. For in vitro analyses, the plant tissues (roots and leaves) were incubated for 16 hr with serial dilutions of 263K-brain homogenate ranging from 10 1 to 10 8. Roots and leaves were washed thoroughly and analyzed for the presence of PrPSc by serial PMCA (Morales et al., 2012). The results show that even highly diluted PrPSc can bind to roots and leaves and sustain PrPC conversion (Figure 1A). Although a direct comparison cannot be made, because of differences on the effective surface, roots appear to retain PrPSc better than leaves. However, both roots and leaves capture PrPSc efficiently, even at very small concentrations, equivalent to those present in biological fluids, such as blood and urine (Chen et al., 2010). By comparing the detection of PrPSc-bound to plants (Figure 1A) with an experiment in which the same dilutions of 263K brain homogenate were added directly to the tubes containing normal brain homogenate and an equivalent piece of leaves or roots (Figure 1B), we can estimate that a high proportion of PrPSc present in the sample was attached to the plant tissue. Importantly, no detection of PrPSc was observed when leaves and roots were exposed to normal brain homogenate (Figure 1C). However, comparing PMCA amplification in the presence (Figure 1B) or in the absence (Figure S1A) of plant tissue, it is possible to appreciate that plants (both leaves and roots) partially inhibits the PMCA reaction. This explains why in most of the experiments with plants, protease-resistant PrPSc is only observed after two rounds of PMCA. In our current PMCA settings, no false-positive PrPSc signals were ever detectable when samples did not contain PrPSc inoculum (Figure S1B). These results indicate that leaves and roots can efficiently bind PrPSc, which remains able to catalyze PrPC to PrPSc conversion, leading to prion replication. In these experiments, plant tissues were incubated with prions for 16 hr, but a similar experiment in which roots and leaves were exposed to a 10 5 dilution of 263K brain homogenate for different times, we found that as little as 2 min of incubation was sufficient for the efficient contamination of plants (Figure S2).
Animals Can Be Infected by Oral Administration of Prion-Contaminated Plants
To investigate whether prion-contaminated plants were able to infect animals by ingestion, leaves and roots previously incubated with either 263K-infected or control hamster brain homogenates were orally administered into naive hamsters. After exposure, plants were extensively washed five times with water and animals were fed with dried material. As positive controls, we orally administered 750 ml of 5% 263K brain homogenate (same material used to contaminate plant tissue). All animals that ingested prion contaminated leaves and roots developed typical prion disease. Although the incubation times were significantly longer in animals ingesting prions attached to leaves and roots as compared with those fed directly with the brain material, the differences were not as high as one could have expected (Figure 2A). Indeed, incubation periods were 147 ± 10,
159 ± 10, and 164 ± 13 days (mean ± SEM) for the groups inoculated with brain homogenate, and prion contaminated roots and leaves, respectively. Prion disease was confirmed by histological study of PrPSc deposition, astrogliosis, and brain vacuolation (Figure 2B), as well as by biochemical detection of protease-resistant PrPSc by western blot (Figure 2C). None of the animals inoculated with leaves and roots exposed to normal brain homogenate developed disease up to 550 days post-inoculation. Histological analysis did not show any PrPSc staining or disease specific alteration in control animals.
Plants Bind Prions from Different Strains and Species To analyze prion-plant interaction with other species and strains of the prion agent, we performed similar studies as described in Figure 1, by incubating leaves and roots with a preparation containing hamster, murine, cervid, and human prions corresponding to the Hyper, 301C, CWD, and vCJD prion strains, respectively. PrPSc from these strains and species showed good amplification by PMCA, using homologous substrates (Figure S3A). In all cases, leaves and roots bound prions from these species and retained the ability to replicate in vitro (Figure S3B), indicating that the interaction of PrPSc with plants is a general feature of infectious prions.
Contamination of Plants with Prions Excreted in Urine and Feces
Under natural conditions, it is likely that the main source of prions in the environment comes from secretory and excretory fluids, such as saliva, urine, and feces. We and others have shown that PrPSc is released in these fluids and excretions in various animal species (Gonzalez-Romero et al., 2008; Haley et al., 2009, 2011; Maddison et al., 2010; Terry et al., 2011; Moda et al., 2014). It has been estimated that the amount of infectious prions spread by excreta during the animals’ lifespan could match or even surpass the quantity present in the brain of a symptomatic individual (Tamgu¨ ney et al., 2009). To study whether plant tissue can be contaminated by waste products excreted from prion-infected hamsters and deer, leaves and roots were incubated with samples of urine and feces and the presence of PrPSc analyzed by serial rounds of PMCA. For these experiments, plant tissues were incubated for 1 hr with urine or feces homogenates obtained either from 263K-infected hamsters or CWD-affected cervids. This time was chosen because longer incubation with these biological fluids affected the integrity of the plant tissue. After being thoroughly washed and dried, PrPSc attached to leaves and roots was detected by PMCA. The results clearly show that PrPSc was readily detectable after three or four rounds of PMCA in samples of wheat grass leaves and roots exposed to both urine and feces from 263K sick hamsters (Figure 3A) and CWD-affected cervids (Figure 3B). Comparing these results with studies of the direct detection of PrPSc in urine and feces (Figures 3A and 3B), it seems that the majority of PrPSc present in these waste products was effectively attached to leaves and roots. No signal was observed in plant tissue exposed to urine or feces coming from non-infected hamsters.
Prions Bind to Living Plants
To investigate a more natural scenario for prion contamination of living plants, we sprayed the leaves of wheat grass with a preparation containing 1% 263K hamster brain homogenate. Plants were let to grow for different times after exposure, and PrPSc was detected in the leaves by PMCA in duplicates for each time point. The results show that PrPSc was able to bind to leaves and remained attached to the living plants for at least 49 days after exposure (Figure 4). Considering that PrPSc signal was detectable normally in the second or third round of PMCA without obvious trend in relation to time, we conclude that the relative amount of PrPSc present in leaves did not appear to change substantially over time. These data indicate that PrPSc can be retained in living plants for at least several weeks after a simple contact with prion contaminated materials, and PrPSc remains competent to drive prion replication.
Plants Uptake Prions from Contaminated Soil
The experiments described above were done by exposure of the surface of leaves and roots with different solutions containing prions. To evaluate whether living plants can uptake PrPSc from contaminated soil, we grew barley grass plants on soil that was contaminated by addition of 263K brain homogenate. Plants were grown for 1 or 3 weeks under conditions that carefully prevented any direct contact of the aerial part of the plant with the soil. After this time, pieces of stem and leaves were collected and analyzed for the presence of PrPSc by PMCA. As shown in Figure 5A, all plants grown for 3 weeks in contaminated soil contained PrPSc in their stem, albeit in small quantities that required four serial rounds of PMCA for detection. One of the four plants analyzed contained a detectable amount of PrPSc in the leaves (Figure 5B), indicating that prions were uptaken from the soil and transported into the aerial parts of the plants, far from the soil. These results differ from a recent article reporting that infectious prions were not detectable in above the ground tissues of wheat plants exposed to CWD prions (Rasmussen et al., 2014). The lack of detection in this article is most likely due to the low sensitive techniques (western blots or ELISA) employed to analyze the presence of PrPSc. Indeed, as we reported previously, PMCA has a power of detection, which is several millions times higher than western blots or ELISA (Saa´ et al., 2006). In order to estimate the amount of PrPSc present in stem and leaves coming from contaminated soil, we performed a quantitative PMCA study, as previously described (Chen et al., 2010). Unfortunately, by comparing the PMCA amplification in the absence or the presence of plant tissue, it is possible to conclude that stems and leaves substantially interfered with the PMCA procedure, and thus the calculation cannot be very precise (Figure S4). Indeed, after two rounds of PMCA we cannot detect any protease-resistant PrPSc, but on the third round we observed the maximum amplification (10 9), presumably because at this round the concentration of PMCA inhibitors has been reduced enough to permit good amplification. At this point, we can estimate that the amount of PrPSc that reaches the stem and leaves from contaminated soil is equivalent to the PrPSc concentration present in a 10 6 to 10 9 dilution of sick brain homogenate. Nevertheless, this result is interesting, because it indicates that the amount of prions uptaken from soil and transported to aerial parts of the plant is within the infectious range. Indeed, titration studies showed that the last infectious dilution of a 263K brain homogenate is 10 9 (Gregori et al., 2006).
This study shows that plants can efficiently bind prions contained in brain extracts from diverse prion infected animals, including CWD-affected cervids. PrPSc attached to leaves and roots from wheat grass plants remains capable of seeding prion replication in vitro. Surprisingly, the small quantity of PrPSc naturally excreted in urine and feces from sick hamster or cervids was enough to efficiently contaminate plant tissue. Indeed, our results suggest that the majority of excreted PrPSc is efficiently captured by plants’ leaves and roots. Moreover, leaves can be contaminated by spraying them with a prion-containing extract, and PrPSc remains detectable in living plants for as long as the study wasperformed (several weeks). Remarkably, prion contaminated plants transmit prion disease to animals upon ingestion, producing a 100% attack rate and incubation periods not substantially longer than direct oral administration of sick brain homogenates. Finally, an unexpected but exciting result was that plants were able to uptake prions from contaminated soil and transport them to aerial parts of the plant tissue. Although it may seem farfetched that plants can uptake proteins from the soil and transport it to the parts above the ground, there are already published reports of this phenomenon (McLaren et al., 1960; Jensen and McLaren, 1960; Paungfoo-Lonhienne et al., 2008). The high resistance of prions to degradation and their ability to efficiently cross biological barriers may play a role in this process. The mechanism by which plants bind, retain, uptake, and transport prions is unknown. Weare currently studying the way in which prions interact with plants using purified, radioactively labeled PrPSc to determine specificity of the interaction, association constant, reversibility, saturation, movement, etc.
Epidemiological studies have shown numerous instances of scrapie or CWD recurrence upon reintroduction of animals on pastures previously exposed to prion-infected animals. Indeed, reappearance of scrapie has been documented following fallow periods of up to 16 years (Georgsson et al., 2006), and pastures were shown to retain infectious CWD prions for at least 2 years after exposure (Miller et al., 2004). It is likely that the environmentally mediated transmission of prion diseases depends upon the interaction of prions with diverse elements, including soil, water, environmental surfaces, various invertebrate animals, and plants. However, since plants are such an important component of the environment and also a major source of food for many animal species, including humans, our results may have far-reaching implications for animal and human health. Currently, the perception of the risk for animal-to-humanprion transmissionhas beenmostly limited to consumption or exposure to contaminated meat; our results indicate that plants might also be an important vector of transmission that needs to be considered in risk assessment.
snip...see full text here ;
Grass Plants Bind, Retain, Uptake, and Transport Infectious Prions
Friday, September 27, 2013
Uptake of Prions into Plants
Tuesday, December 20, 2011
CHRONIC WASTING DISEASE CWD WISCONSIN Almond Deer (Buckhorn Flats) FarmUpdate DECEMBER 2011The CWD infection rate was nearly 80%, the highest ever in a North American captive herd. RECOMMENDATION: That the Board approve the purchase of 80acres of land for $465,000 for the Statewide Wildlife Habitat Program inPortage County and approve the restrictions on public use of the site.SUMMARY:
For Immediate Release Thursday, October 2, 2014
Dustin Vande Hoef 515/281-3375 or 515/326-1616 (cell) or Dustin.VandeHoef@IowaAgriculture.gov
TEST RESULTS FROM CAPTIVE DEER HERD WITH CHRONIC WASTING DISEASE RELEASED 79.8 percent of the deer tested positive for the disease
DES MOINES – The Iowa Department of Agriculture and Land Stewardship today announced that the test results from the depopulation of a quarantined captive deer herd in north-central Iowa showed that 284 of the 356 deer, or 79.8% of the herd, tested positive for Chronic Wasting Disease (CWD). The owners of the quarantined herd have entered into a fence maintenance agreement with the Iowa Department of Agriculture and Land Stewardship,which requires the owners to maintain the 8’ foot perimeter fence around the herd premises for five years after the depopulation was complete and the premises had been cleaned and disinfected CWD is a progressive, fatal, degenerative neurological disease of farmed and free-ranging deer, elk, and moose. There is no known treatment or vaccine for CWD. CWD is not a disease that affects humans.On July 18, 2012, USDA Animal and Plant Health Inspection Service’s (APHIS)National Veterinary Services Lab in Ames, IA confirmed that a male whitetail deer harvested from a hunting preserve in southeast IA was positive for CWD. An investigation revealed that this animal had just been introduced into the hunting preserve from the above-referenced captive deer herd in north-central Iowa.The captive deer herd was immediately quarantined to prevent the spread of CWD. The herd has remained in quarantine until its depopulation on August 25 to 27, 2014.The Iowa Department of Agriculture and Land Stewardship participated in a joint operation to depopulate the infected herd with USDA Veterinary Services, which was the lead agency, and USDA Wildlife Services.Federal indemnity funding became available in 2014. USDA APHIS appraised the captive deer herd of 376 animals at that time, which was before depopulation and testing, at $1,354,250. At that time a herd plan was developed with the owners and officials from USDA and the Iowa Department of Agriculture and Land Stewardship.Once the depopulation was complete and the premises had been cleaned and disinfected, indemnity of $917,100.00 from the USDA has been or will be paid to the owners as compensation for the 356 captive deer depopulated.The Iowa Department of Agriculture and Land Stewardship operates a voluntary CWD program for farms that sell live animals. Currently 145 Iowa farms participate in the voluntary program. The above-referenced captive deer facility left the voluntary CWD program prior to the discovery of the disease as they had stopped selling live animals. All deer harvested in a hunting preserve must be tested for CWD. -30-
*** see history of this CWD blunder here ;
On June 5, 2013, DNR conducted a fence inspection, after gaining approval from surrounding landowners, and confirmed that the fenced had beencut or removed in at least four separate locations; that the fence had degraded and was failing to maintain the enclosure around the Quarantined Premises in at least one area; that at least three gates had been opened;and that deer tracks were visible in and around one of the open areas in the sand on both sides of the fence, evidencing movement of deer into the Quarantined Premises.
Tuesday, October 07, 2014
*** Wisconsin white-tailed deer tested positive for CWD on a Richland County breeding farm, and a case of CWD has been discovered on a Marathon County hunting preserve
*** Wisconsin 16 age limit on testing dead deer Game Farm CWD Testing Protocol Needs To Be Revised
Approximately 4,200 fawns, defined as deer under 1 year of age, were sampled from the eradication zone over the last year. The majority of fawns sampled were between the ages of 5 to 9 months, though some were as young as 1 month.
*** Two of the six fawns with CWD detected were 5 to 6 months old.
All six of the positive fawns were taken from the core area of the CWD eradication zone where the highest numbers of positive deer have been identified. ...
"Finding CWD prions in both lymph and brain tissues of deer this young is slightly surprising," said Langenberg, "and provides information that CWD infection and illness may progress more rapidly in a white-tailed deer than previously suspected. Published literature suggests that CWD doesn't cause illness in a deer until approximately 16 months of age. Our fawn data shows that a few wild white-tailed deer may become sick from CWD or may transmit the disease before they reach that age of 16 months." ... see full text and more here ; Saturday, February 04, 2012
Wisconsin 16 MONTH age limit on testing dead deer Game Farm CWD Testing Protocol Needs To Be Revised
Thursday, July 03, 2014
*** How Chronic Wasting Disease is affecting deer population and what’s the risk to humans and pets?
Tuesday, July 01, 2014
*** CHRONIC WASTING DISEASE CWD TSE PRION DISEASE, GAME FARMS, AND POTENTIAL RISK FACTORS THERE FROM
spreading cwd around...
Between 1996 and 2002, chronic wasting disease was diagnosed in 39 herds of farmed elk in Saskatchewan in a single epidemic. All of these herds were depopulated as part of the Canadian Food Inspection Agency’s (CFIA) disease eradication program. Animals, primarily over 12 mo of age, were tested for the presence CWD prions following euthanasia. Twenty-one of the herds were linked through movements of live animals with latent CWD from a single infected source herd in Saskatchewan, 17 through movements of animals from 7 of the secondarily infected herds.
***The source herd is believed to have become infected via importation of animals from a game farm in South Dakota where CWD was subsequently diagnosed (7,4). A wide range in herd prevalence of CWD at the time of herd depopulation of these herds was observed. Within-herd transmission was observed on some farms, while the disease remained confined to the introduced animals on other farms.
spreading cwd around...
Friday, May 13, 2011
Chronic Wasting Disease (CWD) outbreaks and surveillance program in the Republic of Korea
Hyun-Joo Sohn, Yoon-Hee Lee, Min-jeong Kim, Eun-Im Yun, Hyo-Jin Kim, Won-Yong Lee, Dong-Seob Tark, In- Soo Cho, Foreign Animal Disease Research Division, National Veterinary Research and Quarantine Service, Republic of Korea
Chronic wasting disease (CWD) has been recognized as an important prion disease in native North America deer and Rocky mountain elks. The disease is a unique member of the transmissible spongiform encephalopathies (TSEs), which naturally affects only a few species. CWD had been limited to USA and Canada until 2000.
On 28 December 2000, information from the Canadian government showed that a total of 95 elk had been exported from farms with CWD to Korea. These consisted of 23 elk in 1994 originating from the so-called “source farm” in Canada, and 72 elk in 1997, which had been held in pre export quarantine at the “source farm”.Based on export information of CWD suspected elk from Canada to Korea, CWD surveillance program was initiated by the Ministry of Agriculture and Forestry (MAF) in 2001.
All elks imported in 1997 were traced back, however elks imported in 1994 were impossible to identify. CWD control measures included stamping out of all animals in the affected farm, and thorough cleaning and disinfection of the premises. In addition, nationwide clinical surveillance of Korean native cervids, and improved measures to ensure reporting of CWD suspect cases were implemented.
Total of 9 elks were found to be affected. CWD was designated as a notifiable disease under the Act for Prevention of Livestock Epidemics in 2002.
Additional CWD cases - 12 elks and 2 elks - were diagnosed in 2004 and 2005.
Since February of 2005, when slaughtered elks were found to be positive, all slaughtered cervid for human consumption at abattoirs were designated as target of the CWD surveillance program. Currently, CWD laboratory testing is only conducted by National Reference Laboratory on CWD, which is the Foreign Animal Disease Division (FADD) of National Veterinary Research and Quarantine Service (NVRQS).
In July 2010, one out of 3 elks from Farm 1 which were slaughtered for the human consumption was confirmed as positive. Consequently, all cervid – 54 elks, 41 Sika deer and 5 Albino deer – were culled and one elk was found to be positive. Epidemiological investigations were conducted by Veterinary Epidemiology Division (VED) of NVRQS in collaboration with provincial veterinary services.
Epidemiologically related farms were found as 3 farms and all cervid at these farms were culled and subjected to CWD diagnosis. Three elks and 5 crossbreeds (Red deer and Sika deer) were confirmed as positive at farm 2.
All cervids at Farm 3 and Farm 4 – 15 elks and 47 elks – were culled and confirmed as negative.
Further epidemiological investigations showed that these CWD outbreaks were linked to the importation of elks from Canada in 1994 based on circumstantial evidences.
In December 2010, one elk was confirmed as positive at Farm 5. Consequently, all cervid – 3 elks, 11 Manchurian Sika deer and 20 Sika deer – were culled and one Manchurian Sika deer and seven Sika deer were found to be positive. This is the first report of CWD in these sub-species of deer. Epidemiological investigations found that the owner of the Farm 2 in CWD outbreaks in July 2010 had co-owned the Farm 5.
In addition, it was newly revealed that one positive elk was introduced from Farm 6 of Jinju-si Gyeongsang Namdo. All cervid – 19 elks, 15 crossbreed (species unknown) and 64 Sika deer – of Farm 6 were culled, but all confirmed as negative.
”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.
Sunday, January 06, 2013
USDA TO PGC ONCE CAPTIVES ESCAPE
*** "it‘s no longer its business.”
Tuesday, October 21, 2014
Pennsylvania Department of Agriculture Tenth Pennsylvania Captive Deer Tests Positive for Chronic Wasting Disease CWD TSE PRION DISEASE
Thursday, October 23, 2014
FIRST CASE OF CHRONIC WASTING DISEASE CONFIRMED IN OHIO ON PRIVATE PRESERVE
Thursday, April 02, 2015
OHIO CONFIRMS SECOND POSTIVE CHRONIC WASTING DISEASE CWD on Yoder's properties near Millersburg
Wednesday, February 11, 2015
World Class Whitetails quarantined CWD deer Daniel M. Yoder charged with two counts of tampering with evidence
Tuesday, July 01, 2014
*** CHRONIC WASTING DISEASE CWD TSE PRION DISEASE, GAME FARMS, AND POTENTIAL RISK FACTORS THERE FROM ***
Thursday, July 03, 2014
*** How Chronic Wasting Disease is affecting deer population and what’s the risk to humans and pets? ***
Friday, April 24, 2015
The placenta shed from goats with classical scrapie is infectious to goat kids and lambs
Wednesday, April 22, 2015
Circulation of prions within dust on a scrapie affected farm
Thursday, April 30, 2015
Immediate and ongoing detection of prions in the blood of hamsters and deer following oral, nasal, or blood inoculations
***please read this***
98 | Veterinary Record | January 24, 2015
Scrapie: a particularly persistent pathogen
Resistant prions in the environment have been the sword of Damocles for scrapie control and eradication. Attempts to establish which physical and chemical agents could be applied to inactivate or moderate scrapie infectivity were initiated in the 1960s and 1970s,with the first study of this type focusing on the effect of heat treatment in reducing prion infectivity (Hunter and Millson 1964). Nowadays, most of the chemical procedures that aim to inactivate the prion protein are based on the method developed by Kimberlin and collaborators (1983). This procedure consists of treatment with 20,000 parts per million free chlorine solution, for a minimum of one hour, of all surfaces that need to be sterilised (in laboratories, lambing pens, slaughterhouses, and so on). Despite this, veterinarians and farmers may still ask a range of questions, such as ‘Is there an official procedure published somewhere?’ and ‘Is there an international organisation which recommends and defines the exact method of scrapie decontamination that must be applied?’
From a European perspective, it is difficult to find a treatment that could be applied, especially in relation to the disinfection of surfaces in lambing pens of affected flocks. A 999/2001 EU regulation on controlling spongiform encephalopathies (European Parliament and Council 2001) did not specify a particular decontamination measure to be used when an outbreak of scrapie is diagnosed. There is only a brief recommendation in Annex VII concerning the control and eradication of transmissible spongiform encephalopathies (TSE s).
Chapter B of the regulation explains the measures that must be applied if new caprine animals are to be introduced to a holding where a scrapie outbreak has previously been diagnosed. In that case, the statement indicates that caprine animals can be introduced ‘provided that a cleaning and disinfection of all animal housing on the premises has been carried out following destocking’.
Issues around cleaning and disinfection are common in prion prevention recommendations, but relevant authorities, veterinarians and farmers may have difficulties in finding the specific protocol which applies. The European Food and Safety Authority (EFSA ) published a detailed report about the efficacy of certain biocides, such as sodium hydroxide, sodium hypochlorite, guanidine and even a formulation of copper or iron metal ions in combination with hydrogen peroxide, against prions (EFSA 2009). The report was based on scientific evidence (Fichet and others 2004, Lemmer and others 2004, Gao and others 2006, Solassol and others 2006) but unfortunately the decontamination measures were not assessed under outbreak conditions.
The EFSA Panel on Biological Hazards recently published its conclusions on the scrapie situation in the EU after 10 years of monitoring and control of the disease in sheep and goats (EFSA 2014), and one of the most interesting findings was the Icelandic experience regarding the effect of disinfection in scrapie control. The Icelandic plan consisted of: culling scrapie-affected sheep or the whole flock in newly diagnosed outbreaks; deep cleaning and disinfection of stables, sheds, barns and equipment with high pressure washing followed by cleaning with 500 parts per million of hypochlorite; drying and treatment with 300 ppm of iodophor; and restocking was not permitted for at least two years. Even when all of these measures were implemented, scrapie recurred on several farms, indicating that the infectious agent survived for years in the environment, even as many as 16 years after restocking (Georgsson and others 2006).
In the rest of the countries considered in the EFSA (2014) report, recommendations for disinfection measures were not specifically defined at the government level. In the report, the only recommendation that is made for sheep is repopulation with sheep with scrapie-resistant genotypes. This reduces the risk of scrapie recurrence but it is difficult to know its effect on the infection.
Until the EFSA was established (in May 2003), scientific opinions about TSE s were provided by the Scientific Steering Committee (SSC) of the EC, whose advice regarding inactivation procedures focused on treating animal waste at high temperatures (150°C for three hours) and high pressure alkaline hydrolysis (SSC 2003). At the same time, the TSE Risk Management Subgroup of the Advisory Committee on Dangerous Pathogens (ACDP) in the UK published guidance on safe working and the prevention of TSE infection. Annex C of the ACDP report established that sodium hypochlorite was considered to be effective, but only if 20,000 ppm of available chlorine was present for at least one hour, which has practical limitations such as the release of chlorine gas, corrosion, incompatibility with formaldehyde, alcohols and acids, rapid inactivation of its active chemicals and the stability of dilutions (ACDP 2009).
In an international context, the World Organisation for Animal Health (OIE) does not recommend a specific disinfection protocol for prion agents in its Terrestrial Code or Manual. Chapter 4.13 of the Terrestrial Code, General recommendations on disinfection and disinsection (OIE 2014), focuses on foot-and-mouth disease virus, mycobacteria and Bacillus anthracis, but not on prion disinfection. Nevertheless, the last update published by the OIE on bovine spongiform encephalopathy (OIE 2012) indicates that few effective decontamination techniques are available to inactivate the agent on surfaces, and recommends the removal of all organic material and the use of sodium hydroxide, or a sodium hypochlorite solution containing 2 per cent available chlorine, for more than one hour at 20ºC.
The World Health Organization outlines guidelines for the control of TSE s, and also emphasises the importance of mechanically cleaning surfaces before disinfection with sodium hydroxide or sodium hypochlorite for one hour (WHO 1999).
Finally, the relevant agencies in both Canada and the USA suggest that the best treatments for surfaces potentially contaminated with prions are sodium hydroxide or sodium hypochlorite at 20,000 ppm. This is a 2 per cent solution, while most commercial household bleaches contain 5.25 per cent sodium hypochlorite. It is therefore recommended to dilute one part 5.25 per cent bleach with 1.5 parts water (CDC 2009, Canadian Food Inspection Agency 2013).
So what should we do about disinfection against prions? First, it is suggested that a single protocol be created by international authorities to homogenise inactivation procedures and enable their application in all scrapie-affected countries. Sodium hypochlorite with 20,000 ppm of available chlorine seems to be the procedure used in most countries, as noted in a paper summarised on p 99 of this issue of Veterinary Record (Hawkins and others 2015). But are we totally sure of its effectiveness as a preventive measure in a scrapie outbreak? Would an in-depth study of the recurrence of scrapie disease be needed?
What we can conclude is that, if we want to fight prion diseases, and specifically classical scrapie, we must focus on the accuracy of diagnosis, monitoring and surveillance; appropriate animal identification and control of movements; and, in the end, have homogeneous and suitable protocols to decontaminate and disinfect lambing barns, sheds and equipment available to veterinarians and farmers. Finally, further investigations into the resistance of prion proteins in the diversity of environmental surfaces are required.
98 | Veterinary Record | January 24, 2015
Persistence of ovine scrapie infectivity in a farm environment following cleaning and decontamination
Steve A. C. Hawkins, MIBiol, Pathology Department1, Hugh A. Simmons, BVSc MRCVS, MBA, MA Animal Services Unit1, Kevin C. Gough, BSc, PhD2 and Ben C. Maddison, BSc, PhD3 + Author Affiliations
1Animal and Plant Health Agency, Woodham Lane, New Haw, Addlestone, Surrey KT15 3NB, UK 2School of Veterinary Medicine and Science, The University of Nottingham, Sutton Bonington, Loughborough, Leicestershire LE12 5RD, UK 3ADAS UK, School of Veterinary Medicine and Science, The University of Nottingham, Sutton Bonington, Loughborough, Leicestershire LE12 5RD, UK E-mail for correspondence: email@example.com Abstract Scrapie of sheep/goats and chronic wasting disease of deer/elk are contagious prion diseases where environmental reservoirs are directly implicated in the transmission of disease. In this study, the effectiveness of recommended scrapie farm decontamination regimens was evaluated by a sheep bioassay using buildings naturally contaminated with scrapie. Pens within a farm building were treated with either 20,000 parts per million free chorine solution for one hour or were treated with the same but were followed by painting and full re-galvanisation or replacement of metalwork within the pen. Scrapie susceptible lambs of the PRNP genotype VRQ/VRQ were reared within these pens and their scrapie status was monitored by recto-anal mucosa-associated lymphoid tissue. All animals became infected over an 18-month period, even in the pen that had been subject to the most stringent decontamination process. 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.
Thorough pressure washing of a pen had no effect on the amount of bioavailable scrapie infectivity (pen B). The routine removal of prions from surfaces within a laboratory setting is treatment for a minimum of one hour with 20,000 ppm free chlorine, a method originally based on the use of brain macerates from infected rodents to evaluate the effectiveness of decontamination (Kimberlin and others 1983). Further studies have also investigated the effectiveness of hypochlorite disinfection of metal surfaces to simulate the decontamination of surgical devices within a hospital setting. Such treatments with hypochlorite solution were able to reduce infectivity by 5.5 logs to lower than the sensitivity of the bioassay used (Lemmer and others 2004). Analogous treatment of the pen surfaces did not effectively remove the levels of scrapie infectivity over that of the control pens, indicating that this method of decontamination is not effective within a farm setting. This may be due to the high level of biological matrix that is present upon surfaces within the farm environment, which may reduce the amount of free chlorine available to inactivate any infectious prion. Remarkably 1/5 sheep introduced into pen D had also became scrapie positive within nine months, with all animals in this pen being RAMALT positive by 18 months of age. Pen D was no further away from the control pen (pen A) than any of the other pens within this barn. Localised hot spots of infectivity may be present within scrapie-contaminated environments, but it is unlikely that pen D area had an amount of scrapie contamination that was significantly different than the other areas within this building. Similarly, there were no differences in how the biosecurity of pen D was maintained, or how this pen was ventilated compared with the other pens. This observation, perhaps, indicates the slower kinetics of disease uptake within this pen and is consistent with a more thorough prion removal and recontamination. These observations may also account for the presence of inadvertent scrapie cases within other studies, where despite stringent biosecurity, control animals have become scrapie positive during challenge studies using barns that also housed scrapie-affected animals (Ryder and others 2009). The bioassay data indicate that the exposure of the sheep to a farm environment after decontamination efforts thought to be effective in removing scrapie is sufficient for the animals to become infected with scrapie. The main exposure routes within this scenario are likely to be via the oral route, during feeding and drinking, and respiratory and conjunctival routes. It has been demonstrated that scrapie infectivity can be efficiently transmitted via the nasal route in sheep (Hamir and others 2008), as is the case for CWD in both murine models and in white-tailed deer (Denkers and others 2010, 2013). Recently, it has also been demonstrated that CWD prions presented as dust when bound to the soil mineral montmorillonite can be infectious via the nasal route (Nichols and others 2013). When considering pens C and D, the actual source of the infectious agent in the pens is not known, it is possible that biologically relevant levels of prion survive on surfaces during the decontamination regimen (pen C). With the use of galvanising and painting (pen D) covering and sealing the surface of the pen, it is possible that scrapie material recontaminated the pens by the movement of infectious prions contained within dusts originating from other parts of the barn that were not decontaminated or from other areas of the farm.
Given that scrapie prions are widespread on the surfaces of affected farms (Maddison and others 2010a), irrespective of the source of the infectious prions in the pens, this study clearly highlights the difficulties that are faced with the effective removal of environmentally associated scrapie infectivity. This is likely to be paralleled in CWD which shows strong similarities to scrapie in terms of both the dissemination of prions into the environment and the facile mode of disease transmission. These data further contribute to the understanding that prion diseases can be highly transmissible between susceptible individuals not just by direct contact but through highly stable environmental reservoirs that are refractory to decontamination.
The presence of these environmentally associated prions in farm buildings make the control of these diseases a considerable challenge, especially in animal species such as goats where there is lack of genetic resistance to scrapie and, therefore, no scope to re-stock farms with animals that are resistant to scrapie.
Scrapie Sheep Goats Transmissible spongiform encephalopathies (TSE) Accepted October 12, 2014. Published Online First 31 October 2014
Tuesday, December 16, 2014
Evidence for zoonotic potential of ovine scrapie prions
Hervé Cassard,1, n1 Juan-Maria Torres,2, n1 Caroline Lacroux,1, Jean-Yves Douet,1, Sylvie L. Benestad,3, Frédéric Lantier,4, Séverine Lugan,1, Isabelle Lantier,4, Pierrette Costes,1, Naima Aron,1, Fabienne Reine,5, Laetitia Herzog,5, Juan-Carlos Espinosa,2, Vincent Beringue5, & Olivier Andréoletti1, Affiliations Contributions Corresponding author Journal name: Nature Communications Volume: 5, Article number: 5821 DOI: doi:10.1038/ncomms6821 Received 07 August 2014 Accepted 10 November 2014 Published 16 December 2014 Article tools Citation Reprints Rights & permissions Article metrics
Although Bovine Spongiform Encephalopathy (BSE) is the cause of variant Creutzfeldt Jakob disease (vCJD) in humans, the zoonotic potential of scrapie prions remains unknown. Mice genetically engineered to overexpress the human prion protein (tgHu) have emerged as highly relevant models for gauging the capacity of prions to transmit to humans. These models can propagate human prions without any apparent transmission barrier and have been used used to confirm the zoonotic ability of BSE. Here we show that a panel of sheep scrapie prions transmit to several tgHu mice models with an efficiency comparable to that of cattle BSE. The serial transmission of different scrapie isolates in these mice led to the propagation of prions that are phenotypically identical to those causing sporadic CJD (sCJD) in humans. These results demonstrate that scrapie prions have a zoonotic potential and raise new questions about the possible link between animal and human prions.
Subject terms: Biological sciences• Medical research At a glance
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.
Friday, January 30, 2015
Scrapie: a particularly persistent pathogen
Monday, November 3, 2014
Persistence of ovine scrapie infectivity in a farm environment following cleaning and decontamination
Detection of Environmentally Associated PrPSc on a Farm with Endemic Scrapie
Ben C. Maddison,1 Claire A. Baker,1 Helen C. Rees,1 Linda A. Terry,2 Leigh Thorne,2 Susan J. Belworthy2 and Kevin C. Gough3 1ADAS-UK LTD; Department of Biology; University of Leicester; Leicester, UK; 2Veterinary Laboratories Agency; Surry, KT UK; 3Department of Veterinary Medicine and Science; University of Nottingham; Sutton Bonington, Loughborough UK
Key words: scrapie, evironmental persistence, sPMCA
Ovine scrapie shows considerable horizontal transmission, yet the routes of transmission and specifically the role of fomites in transmission remain poorly defined. Here we present biochemical data demonstrating that on a scrapie-affected sheep farm, scrapie prion contamination is widespread. It was anticipated at the outset that if prions contaminate the environment that they would be there at extremely low levels, as such the most sensitive method available for the detection of PrPSc, serial Protein Misfolding Cyclic Amplification (sPMCA), was used in this study. We investigated the distribution of environmental scrapie prions by applying ovine sPMCA to samples taken from a range of surfaces that were accessible to animals and could be collected by use of a wetted foam swab. Prion was amplified by sPMCA from a number of these environmental swab samples including those taken from metal, plastic and wooden surfaces, both in the indoor and outdoor environment. At the time of sampling there had been no sheep contact with these areas for at least 20 days prior to sampling indicating that prions persist for at least this duration in the environment. These data implicate inanimate objects as environmental reservoirs of prion infectivity which are likely to contribute to disease transmission.
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
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.
*** After a natural route of exposure, 100% of white-tailed deer were susceptible to scrapie.
*** We conclude that TSE infectivity is likely to survive burial for long time periods with minimal loss of infectivity and limited movement from the original burial site. However PMCA results have shown that there is the potential for rainwater to elute TSE related material from soil which could lead to the contamination of a wider area. These experiments reinforce the importance of risk assessment when disposing of TSE risk materials.
*** The results show that even highly diluted PrPSc can bind efficiently to polypropylene, stainless steel, glass, wood and stone and propagate the conversion of normal prion protein. For in vivo experiments, hamsters were ic injected with implants incubated in 1% 263K-infected brain homogenate. Hamsters, inoculated with 263K-contaminated implants of all groups, developed typical signs of prion disease, whereas control animals inoculated with non-contaminated materials did not.
PRION 2014 CONFERENCE
CHRONIC WASTING DISEASE CWD
A FEW FINDINGS ;
Conclusions. To our knowledge, this is the first established experimental model of CWD in TgSB3985. We found evidence for co-existence or divergence of two CWD strains adapted to Tga20 mice and their replication in TgSB3985 mice. Finally, we observed phenotypic differences between cervid-derived CWD and CWD/Tg20 strains upon propagation in TgSB3985 mice. Further studies are underway to characterize these strains.
We conclude that TSE infectivity is likely to survive burial for long time periods with minimal loss of infectivity and limited movement from the original burial site. However PMCA results have shown that there is the potential for rainwater to elute TSE related material from soil which could lead to the contamination of a wider area. These experiments reinforce the importance of risk assessment when disposing of TSE risk materials.
The results show that even highly diluted PrPSc can bind efficiently to polypropylene, stainless steel, glass, wood and stone and propagate the conversion of normal prion protein. For in vivo experiments, hamsters were ic injected with implants incubated in 1% 263K-infected brain homogenate. Hamsters, inoculated with 263K-contaminated implants of all groups, developed typical signs of prion disease, whereas control animals inoculated with non-contaminated materials did not.
Our data establish that meadow voles are permissive to CWD via peripheral exposure route, suggesting they could serve as an environmental reservoir for CWD. Additionally, our data are consistent with the hypothesis that at least two strains of CWD circulate in naturally-infected cervid populations and provide evidence that meadow voles are a useful tool for CWD strain typing.
Conclusion. CWD prions are shed in saliva and urine of infected deer as early as 3 months post infection and throughout the subsequent >1.5 year course of infection. In current work we are examining the relationship of prionemia to excretion and the impact of excreted prion binding to surfaces and particulates in the environment.
Conclusion. CWD prions (as inferred by prion seeding activity by RT-QuIC) are shed in urine of infected deer as early as 6 months post inoculation and throughout the subsequent disease course. Further studies are in progress refining the real-time urinary prion assay sensitivity and we are examining more closely the excretion time frame, magnitude, and sample variables in relationship to inoculation route and prionemia in naturally and experimentally CWD-infected cervids.
Conclusions. Our results suggested that the odds of infection for CWD is likely controlled by areas that congregate deer thus increasing direct transmission (deer-to-deer interactions) or indirect transmission (deer-to-environment) by sharing or depositing infectious prion proteins in these preferred habitats. Epidemiology of CWD in the eastern U.S. is likely controlled by separate factors than found in the Midwestern and endemic areas for CWD and can assist in performing more efficient surveillance efforts for the region.
Conclusions. During the pre-symptomatic stage of CWD infection and throughout the course of disease deer may be shedding multiple LD50 doses per day in their saliva. CWD prion shedding through saliva and excreta may account for the unprecedented spread of this prion disease in nature.
see full text and more ;
Monday, June 23, 2014
*** PRION 2014 CONFERENCE CHRONIC WASTING DISEASE CWD
*** Infectious agent of sheep scrapie may persist in the environment for at least 16 years***
Gudmundur Georgsson1, Sigurdur Sigurdarson2 and Paul Brown3
New studies on the heat resistance of hamster-adapted scrapie agent: Threshold survival after ashing at 600°C suggests an inorganic template of replication
Prion Infected Meat-and-Bone Meal Is Still Infectious after Biodiesel Production
Detection of protease-resistant cervid prion protein in water from a CWD-endemic area
A Quantitative Assessment of the Amount of Prion Diverted to Category 1 Materials and Wastewater During Processing
Rapid assessment of bovine spongiform encephalopathy prion inactivation by heat treatment in yellow grease produced in the industrial manufacturing process of meat and bone meals
Friday, December 14, 2012
DEFRA U.K. What is the risk of Chronic Wasting Disease CWD being introduced into Great Britain? A Qualitative Risk Assessment October 2012
In the USA, under the Food and Drug Administration’s BSE Feed Regulation (21 CFR 589.2000) most material (exceptions include milk, tallow, and gelatin) from deer and elk is prohibited for use in feed for ruminant animals. With regards to feed for non-ruminant animals, under FDA law, CWD positive deer may not be used for any animal feed or feed ingredients. For elk and deer considered at high risk for CWD, the FDA recommends that these animals do not enter the animal feed system. However, this recommendation is guidance and not a requirement by law.
Animals considered at high risk for CWD include:
1) animals from areas declared to be endemic for CWD and/or to be CWD eradication zones and
2) deer and elk that at some time during the 60-month period prior to slaughter were in a captive herd that contained a CWD-positive animal.
Therefore, in the USA, materials from cervids other than CWD positive animals may be used in animal feed and feed ingredients for non-ruminants.
The amount of animal PAP that is of deer and/or elk origin imported from the USA to GB can not be determined, however, as it is not specified in TRACES. It may constitute a small percentage of the 8412 kilos of non-fish origin processed animal proteins that were imported from US into GB in 2011.
Overall, therefore, it is considered there is a __greater than negligible risk___ that (nonruminant) animal feed and pet food containing deer and/or elk protein is imported into GB.
There is uncertainty associated with this estimate given the lack of data on the amount of deer and/or elk protein possibly being imported in these products.
36% in 2007 (Almberg et al., 2011). In such areas, population declines of deer of up to 30 to 50% have been observed (Almberg et al., 2011). In areas of Colorado, the prevalence can be as high as 30% (EFSA, 2011). The clinical signs of CWD in affected adults are weight loss and behavioural changes that can span weeks or months (Williams, 2005). In addition, signs might include excessive salivation, behavioural alterations including a fixed stare and changes in interaction with other animals in the herd, and an altered stance (Williams, 2005). These signs are indistinguishable from cervids experimentally infected with bovine spongiform encephalopathy (BSE). Given this, if CWD was to be introduced into countries with BSE such as GB, for example, infected deer populations would need to be tested to differentiate if they were infected with CWD or BSE to minimise the risk of BSE entering the human food-chain via affected venison.
The rate of transmission of CWD has been reported to be as high as 30% and can approach 100% among captive animals in endemic areas (Safar et al., 2008).
In summary, in endemic areas, there is a medium probability that the soil and surrounding environment is contaminated with CWD prions and in a bioavailable form. In rural areas where CWD has not been reported and deer are present, there is a greater than negligible risk the soil is contaminated with CWD prion.
In summary, given the volume of tourists, hunters and servicemen moving between GB and North America, the probability of at least one person travelling to/from a CWD affected area and, in doing so, contaminating their clothing, footwear and/or equipment prior to arriving in GB is greater than negligible. For deer hunters, specifically, the risk is likely to be greater given the increased contact with deer and their environment. However, there is significant uncertainty associated with these estimates.
Therefore, it is considered that farmed and park deer may have a higher probability of exposure to CWD transferred to the environment than wild deer given the restricted habitat range and higher frequency of contact with tourists and returning GB residents.
Friday, December 14, 2012
DEFRA U.K. What is the risk of Chronic Wasting Disease CWD being introduced into Great Britain? A Qualitative Risk Assessment October 2012
BSE RUMINANT FEED BAN FOR CERVIDS AND PETS IN THE USA ?
in short, there is none, and never has been.
I am concerned with pets as well.
I strongly, strenuously, urge the FDA et al and scientist (minus the industry, politicians, and lobbyist there from on all issues), to revisit the foolish voluntary ban on ruminant feed to cervids, and adopt an immediate measure to make mandatory the ban of all ruminant feed to all cervids and pets. ... TSS
FDA WARNING LETTER (14-ATL-04) adulterated under Section 402(a)(4) [21 U.S.C. 342(a)(4)] of the Act, protein derived from mammalian tissues to feeds that may be used for ruminants [21 C.F.R. 589.2000(e)(1)(iii)(B)]
Sunday, December 15, 2013
FDA PART 589 -- SUBSTANCES PROHIBITED FROM USE IN ANIMAL FOOD OR FEED VIOLATIONS OFFICIAL ACTION INDICATED OIA UPDATE DECEMBER 2013 UPDATE
Tuesday, December 23, 2014
FDA PART 589 -- SUBSTANCES PROHIBITED FROM USE IN ANIMAL FOOD OR FEED VIOLATIONS OFFICIAL ACTION INDICATED OAI UPDATE DECEMBER 2014 BSE TSE PRION
DOCKET-- 03D-0186 -- FDA Issues Draft Guidance on Use of Material From Deer and Elk in Animal Feed; Availability Date: Fri, 16 May 2003 11:47:37 -0500 EMC 1 Terry S. Singeltary Sr. Vol #: 1 http://www.fda.gov/ohrms/dockets/dailys/03/Jun03/060903/060903.htm
PLEASE SEE FULL TEXT SUBMISSION ;
Discussion: The C, L and H type BSE cases in Canada exhibit molecular characteristics similar to those described for classical and atypical BSE cases from Europe and Japan. *** This supports the theory that the importation of BSE contaminated feedstuff is the source of C-type BSE in Canada. *** It also suggests a similar cause or source for atypical BSE in these countries. ***
see page 176 of 201 pages...tss
*** Singeltary reply ;
Molecular, Biochemical and Genetic Characteristics of BSE in Canada
Susceptibility of European Red Deer (Cervus elaphus elaphus) to Alimentary Challenge with Bovine Spongiform Encephalopathy
Mark P. Dagleish , * E-mail: firstname.lastname@example.org
Affiliation: Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, Near Edinburgh EH26 0PZ, United Kingdom
⨯ Stuart Martin, Affiliation: Animal Health & Veterinary Laboratories Agency Lasswade, Pentlands Science Park, Bush Loan, Penicuik, Near Edinburgh EH26 0PZ, United Kingdom
⨯ Philip Steele, Affiliation: Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, Near Edinburgh EH26 0PZ, United Kingdom
⨯ Jeanie Finlayson, Affiliation: Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, Near Edinburgh EH26 0PZ, United Kingdom
⨯ Samantha L. Eaton, Affiliation: Neurobiology Division, The Roslin Institute at, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Campus, Midlothian, EH25 9RG, United Kingdom
⨯ Sílvia Sisó, Affiliation: Animal Health & Veterinary Laboratories Agency Lasswade, Pentlands Science Park, Bush Loan, Penicuik, Near Edinburgh EH26 0PZ, United Kingdom
⨯ Paula Stewart, Affiliation: Neurobiology Division, The Roslin Institute at, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Campus, Midlothian, EH25 9RG, United Kingdom
⨯ Natalia Fernández-Borges, Affiliation: CIC bioGUNE, Parque tecnológico de Bizkaia, Derio 48160, Spain
⨯ Scott Hamilton, Affiliation: Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, Near Edinburgh EH26 0PZ, United Kingdom
⨯ Yvonne Pang, Affiliation: Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, Near Edinburgh EH26 0PZ, United Kingdom
⨯ Francesca Chianini, Affiliation: Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, Near Edinburgh EH26 0PZ, United Kingdom
⨯ Hugh W. Reid, Affiliation: Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, Near Edinburgh EH26 0PZ, United Kingdom
⨯ Wilfred Goldmann, Affiliation: Neurobiology Division, The Roslin Institute at, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Campus, Midlothian, EH25 9RG, United Kingdom
⨯ Lorenzo González, Affiliation: Animal Health & Veterinary Laboratories Agency Lasswade, Pentlands Science Park, Bush Loan, Penicuik, Near Edinburgh EH26 0PZ, United Kingdom
⨯ Joaquín Castilla, Affiliations: CIC bioGUNE, Parque tecnológico de Bizkaia, Derio 48160, Spain, IKERBASQUE, Basque Foundation for Science, Bilbao 48013, Bizkaia, Spain
⨯ [ ... ], Martin Jeffrey Affiliation: Animal Health & Veterinary Laboratories Agency Lasswade, Pentlands Science Park, Bush Loan, Penicuik, Near Edinburgh EH26 0PZ, United Kingdom
⨯ [ view all ] [ view less ] Susceptibility of European Red Deer (Cervus elaphus elaphus) to Alimentary Challenge with Bovine Spongiform Encephalopathy Mark P. Dagleish, Stuart Martin, Philip Steele, Jeanie Finlayson, Samantha L. Eaton, Sílvia Sisó, Paula Stewart, Natalia Fernández-Borges, … Scott Hamilton, Yvonne Pang PLOS x Published: January 23, 2015 DOI: 10.1371/journal.pone.0116094
European red deer (Cervus elaphus elaphus) are susceptible to the agent of bovine spongiform encephalopathy, one of the transmissible spongiform encephalopathies, when challenged intracerebrally but their susceptibility to alimentary challenge, the presumed natural route of transmission, is unknown. To determine this, eighteen deer were challenged via stomach tube with a large dose of the bovine spongiform encephalopathy agent and clinical signs, gross and histological lesions, presence and distribution of abnormal prion protein and the attack rate recorded. Only a single animal developed clinical disease, and this was acute with both neurological and respiratory signs, at 1726 days post challenge although there was significant (27.6%) weight loss in the preceding 141 days. The clinically affected animal had histological lesions of vacuolation in the neuronal perikaryon and neuropil, typical of transmissible spongiform encephalopathies. Abnormal prion protein, the diagnostic marker of transmissible encephalopathies, was primarily restricted to the central and peripheral nervous systems although a very small amount was present in tingible body macrophages in the lymphoid patches of the caecum and colon. Serial protein misfolding cyclical amplification, an in vitro ultra-sensitive diagnostic technique, was positive for neurological tissue from the single clinically diseased deer. All other alimentary challenged deer failed to develop clinical disease and were negative for all other investigations. These findings show that transmission of bovine spongiform encephalopathy to European red deer via the alimentary route is possible but the transmission rate is low. Additionally, when deer carcases are subjected to the same regulations that ruminants in Europe with respect to the removal of specified offal from the human food chain, the zoonotic risk of bovine spongiform encephalopathy, the cause of variant Creutzfeldt-Jakob disease, from consumption of venison is probably very low.
Discussion This investigation resulted in the first and only known case, to date, of clinical disease or accumulation of abnormal PrPd in any cervid species due to oral challenge with BSE. The increase in incubation period compared to European red deer challenged with BSE intra-cerebrally (1060 days)  compared to oral challenge (1727 days) is approximately 60% and similar to the differences observed in incubation periods for sheep or goats when challenged with TSE agents by these two routes [40,41]. The neurological clinical signs observed could be broadly related to the spongiform encephalopathy and the accumulation of PrPd in that the restlessness, stereotypic head movements and pacing may be due to compromise of the nucleus accumbens , found in the striatum, and the laboured breathing due to the lesions in the medulla, where the respiratory centre is located . Alternatively, the laboured and audible mouth breathing may have been due to, or contributed to by, compromise of either of the recurrent laryngeal nerves resulting in some degree of laryngeal paralysis but we were unable to determine this. Apart from the gradual loss of body weight, the speed of onset of clinical signs and progression was very rapid but animal welfare requirements precluded any further longitudinal study of these. The clinical signs described for this animal are broadly similar to those reported for clinical BSE in European red deer challenged via the intracerebral route , clinical cases of CWD in deer  and clinical cases of BSE in cattle .
snip...see full text ;
*** Singeltary reply ;
ruminant feed ban for cervids in the United States ?
31 Jan 2015 at 20:14 GMT
*** 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.
Sunday, May 3, 2015
PRION2015 FORT COLLINS
Friday, May 15, 2015
Grass Plants Bind, Retain, Uptake, and Transport Infectious Prions