Sunday, September 1, 2013

Evaluation of the Zoonotic Potential of Transmissible Mink Encephalopathy

Evaluation of the Zoonotic Potential of Transmissible Mink Encephalopathy

 

Emmanuel E. Comoy 1,*, Jacqueline Mikol 1, Marie-Madeleine Ruchoux 1, Valérie Durand 1, Sophie Luccantoni-Freire 1, Capucine Dehen 1, Evelyne Correia 1, Cristina Casalone 2, Juergen A. Richt 3, Justin J. Greenlee 4, Juan Maria Torres 5, Paul Brown 1 and Jean-Philippe Deslys 1

 

1 CEA, Institute of Emerging Diseases and Innovative Therapies (iMETI), Division of Prions and Related Diseases (SEPIA), Route du Panorama, BP6, 92265 Fontenay-aux-Roses, France; E-Mails: jacqueline.mikol@wanadoo.fr (J.M.); mruchoux@yahoo.fr (M.-M.R.); valerie.durand@cea.fr (V.D.); sophie.luccantoni@cea.fr (S.L.); capucine.dehen@cea.fr (C.D.); evelyne.correia@cea.fr (E.C.); paulwbrown@comcast.net (P.B.); jpdeslys@cea.fr (J-P.D.)

 

2 Istituto Zooprofilattico Sperimentale del Piemonte, Via Bologna 148, 10154 Torino, Italy; E-Mail: cristina.casalone@izsto.it (C.C.)

 

3 Kansas State University, College of Veterinary Medicine, K224B Mosier Hall, Manhattan, Kansas 66506-5601 USA; E-Mail: jricht@vet.k-state.edu

 

4 National Animal Disease Center, USDA, Agricultural Research Service, 1920 Dayton Ave, Ames, Iowa 50010 USA; E-Mail: justin.greenlee@ars.usda.gov (J.J.G.)

 

5 Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria, Madrid, Spain; E-mail: jmtorres@inia.es

 

* Author to whom correspondence should be addressed; E-Mail: emmanuel.comoy@cea.fr (E.E.C.); Tel.: +33-46-54-90-05; Fax: +33-46-54-93-19. Received: 27 June 2013; in revised form: 28 July 2013 / Accepted: 30 July 2013 / Published: 30 July 2013

 

Abstract: Successful transmission of Transmissible Mink Encephalopathy (TME) to cattle supports the bovine hypothesis for the still controversial origin of TME outbreaks. Human and primate susceptibility to classical Bovine Spongiform Encephalopathy (c-BSE) and the transmissibility of L-type BSE to macaques indicate a low cattle-to-primate species barrier. We therefore evaluated the zoonotic potential of cattle-adapted TME. In less than two years, this strain induced in cynomolgus macaques a neurological disease similar to L-BSE but distinct from c-BSE. TME derived from another donor species (raccoon) induced a similar disease with even shorter incubation periods. L-BSE and cattle-adapted TME were also transmissible to transgenic mice expressing human prion protein (PrP). Secondary transmissions to transgenic mice expressing bovine PrP maintained the features of the three tested bovine strains (cattle TME, c-BSE and L-BSE) regardless of intermediate host. Thus, TME is the third animal prion strain transmissible to both macaques and humanized transgenic mice, suggesting zoonotic potentials that should be considered in the risk analysis of animal prion diseases for human health. Moreover, the similarities between TME and L-BSE are highly suggestive of a link between these strains, and therefore the possible presence of L-BSE for many decades prior to its identification in USA and Europe.

 

Keywords: primate; prion; transgenic mice; TME; cattle; raccoon; zoonotic potential

 

1. Introduction

 

Transmissible Mink Encephalopathy (TME) is a rare prion disease affecting ranch-reared mink that was reported in four isolated outbreaks in the USA in 1947, 1961, 1963 and 1985 [1], and in several other outbreaks in Canada, East Germany, Finland and the former USSR during the same time period, with prevalence rates as high as 100% and an estimated incubation period of 6 months [2]. Epidemiological studies suggested that each outbreak was due to dietary infection. Several experimental exposures of mink to ruminant prions were performed to identify the exact origin of TME. Low efficiency and rate of transmission were observed after inoculation of mink with sheep scrapie [3] and elk-derived Chronic Wasting Disease (CWD) [4] isolates with an incubation time of 2–3 years, while a 100% success rate of transmission was obtained within 12 months post-exposure to classical Bovine Spongiform Encephalopathy (c-BSE) [5]. However, in all cases, the resulting diseases differed from TME. Conversely, TME was experimentally transmitted to cattle [6,7] inducing a prion disease distinct from c-BSE within 16 to 28 months. Experimental transmissions to conventional and transgenic rodent models suggested similarities between TME and L-BSE [8,9], an atypical cattle prion strain that was incidentally identified several years ago in aged cattle through systematic testing within the framework of the European BSE epizootic [10]. It was speculated that sporadic atypical cattle BSE (H- and/or L- type) might be at the origin of c-BSE [11,12]. These observations support the hypothesis of a bovine origin to TME.

 

Currently, classical BSE is the only animal transmissible spongiform encephalopathy (TSE) considered as a zoonotic disease, since it induces a variant of Creutzfeldt-Jakob disease (CJD) in humans [13–15]. We, and others, demonstrated that the cynomolgus macaque, previously used to demonstrate the transmissibility of human prion diseases [16], constitutes a relevant experimental model to assess the BSE risk for humans [14,17–20]. The same species was also susceptible to L-BSE [21,22], developing a disease distinct from c-BSE. Taken together, these results suggested a low cattle-to-primate species barrier and raised questions about the zoonotic potential of different bovine prion strains. We chose to assess the risk for human health linked to TME-related prion strains by evaluating the transmissibility of cattle-adapted TME in this cynomolgus macaque model, in comparison to raccoon TME as a non-ruminant source of the same prion strain. In parallel, we used transgenic mice overexpressing human or bovine prion protein (PrP) to assess the relevance of our results for human situation.

 

 2. Results and Discussion

 

2.1. Transmission of Cattle-Adapted TME in Experimental Models

 

A primate intracerebrally inoculated with the equivalent of 40 mg of a TME-infected cattle brain (second passage) developed the first neurological signs of disease after less than twenty months of incubation (Table 1). It first showed slowness and weak tremors amplifying with time. Clinical signs then evolved with ataxia, hypermetria, poor vision, and apparent cognitive impairment. Appetite remained normal during the entire 3.5 months clinical period (limited weight loss) and no behavioral changes were noticed (total survival period 23 months). The presence of cerebral spongiosis and protease-resistant prion protein (PrPres) deposition (detailed hereafter) confirmed the presence of prion disease. When another, non-ruminant, source of TME was injected, disease occurred with a similar period of survival (Table 1).

 

Table 1. Survival (incubation and clinical duration) in months of individual cynomolgus macaques exposed to different prion strains.

 

In parallel, several but not all the transgenic mice overexpressing human (Met/Met) PrP (tg650 mice) intracerebrally inoculated with cattle-adapted TME inoculum exhibited cerebral PrPres: partial transmission (75 %) occurred in humanized mice that died after about 18 months of incubation (Figure 1).

 

2.2. Transmission of other cattle prion strains

 

From these results, cattle-adapted TME represents the third cattle prion strain (together with c-BSE and L-BSE) experimentally demonstrated to be transmissible to non-human primates. We confirmed in this study the previously described transmissibility of both L-BSE and c-BSE in both experimental primates [14,21] and transgenic [23,24] models.

 

In the primate model, exposure to L-BSE-infected cattle brain induced a clinical picture with incubation time and duration of illness that are similar to those observed after exposure to cattle-adapted TME, even after exposure to as little as 2.5 mg of brain tissue (Table 1). Conversely, c-BSE infected primates developed a different clinical picture, as previously described [14,21], with longer incubation periods even when they were exposed to 100 mg of brain tissue.

 

A comparison of incubation periods confirmed and magnified the higher virulence of L-BSE for macaque compared to c-BSE, which we had previously observed [21]. Moreover, since incubation periods classically increase with the dilution of initial infectious amount in experimental prion diseases, the similarity of incubation durations for primates exposed to either 25 or 2.5 mg of L-BSE-infected brain is in favor of a substantial amount of infectivity in the brains of cattle infected with the L-BSE prion strain.

 

Figure 1. Transmission studies of bovine prion strains to transgenic mice overexpressing human (tg650) or bovine (tg110) PrP. Tg650 mice (colored in blue) were intracerebrally inoculated with 20 μl of 10 % brain homogenate from cattle infected with adapted TME, L-BSE or c-BSE strains. Tg110 mice (colored in red) were inoculated directly with the same cattle inocula, or with brains from macaques or tg650 mice previously exposed to those cattle inocula. vCJD inoculum was injected as controls. Transmission results are expressed as rates of transmission (%), number of recipient mice (in brackets), and mean ± standard deviation of their incubation periods.

 

In the model of transgenic mice overexpressing human (Met/Met) PrP (tg650 mice), an incomplete transmission rate of 25% of L-BSE was observed after an incubation period of similar duration (18 months) to those from cattle TME-exposed animals, while a 100% transmission rate was observed with c-BSE, but with longer incubations (animals were euthanized 27 months post inoculation, corresponding to the lifespan of these animals in our facilities). These observations are consistent with the results obtained with L-BSE strain by Beringue et al., in this transgenic model [24] and by Kong in another humanized mouse model [25], suggesting a less efficient transmission of L-BSE and TME than c-BSE in this transgenic model, but with a shorter evolution when it occurs.

 

The overexpression of PrP in transgenic mice is often criticized as an element helping to force the way through the species barrier and extrapolation of our results in this model to the human situation should be taken with caution, since transgenic mice expressing physiological levels of human PrP are resistant to L-BSE [26]. Nevertheless, it must be noted that these ‘physiologic’ mice are also resistant to c-BSE, impairing its relevance for assessing the zoonotic potential of animal prion strains. In any case, an efficient transmission of these prion strains to primate, possibly in the presence of a weak cattle-to-primate species barrier, may be extrapolated from our results in the macaque model, which is strengthened by the transgenic model and the current absence of any argument for a zoonotic potential of prion strains derived from other ruminants (ovine or caprine classical or atypical scrapie, wild ruminant CWD).

 

2.3. Comparative Pathologies of the Diseases Induced by the Different Cattle Prions

 

The macaque inoculated with cattle-adapted TME showed widespread cortical spongiosis similar to that in both primates exposed to L-BSE (Figure 2). The spongiosis profile for these three animals was superimposable, with less pronounced lesions in the medulla and cerebellum in cattle TME-infected animal than in L-BSE animals (Figure 3). In the c-BSE-inoculated macaques, spongiosis profiles were different, with more discrete cortical spongiosis and lesions mainly affecting the thalamus, medulla oblongata and cerebellum. When we used a non-cattle (raccoon) TME source, a similar spongiosis profile was observed but with slight modifications (cortical lesions were less pronounced and pallidum and cerebellum were virtually spared).

 

Primates inoculated with L-BSE or cattle TME exhibited a similar diffuse laminar synaptic pattern of PrPres depositions (either fine and sandy or roughly granular) but no evidence of plaques, even when stained with thioflavine T (data not shown), whereas c-BSE-infected animals had weak diffuse synaptic labeling but multiple intensely-stained PrPres aggregates and characteristic plaques [21].

 

Figure 2. Histopathology and PrPres immunostaining. Spongiosis (A–D) and PrPres deposition (E–H) in frontal cortex in primates infected with cattle-adapted TME (A, E), L-BSE (B, F), classical BSE (C, G) or raccoon TME (D, H) (original magnification x200 for spongiosis and x400 for PrPres staining). Immunostaining of PrPres was performed with 3F4 monoclonal anti-PrP antibody after proteinase K treatment as previously described [21]. No staining was observed in the brain of control healthy primates (data not shown) under these conditions.

 

Figure 3. Spongiosis profiles in infected primates. Lesional profiles (based on spongiosis) in primates exposed to cattle-adapted TME (A) L-BSE (B), c-BSE (C) and raccoon TME (D) were defined according to the scoring and areas described by Parchi et al. [27]. Spongiosis profile of c-BSE primates is depicted as the mean among 5 primates exposed to c-BSE. Frontal Cortex (FC) ,Temporal Cortex (TC), Parietal Cortex (PC), Occipital Cortex (OC), Hippocampus (HI), Entorhinal Cortex (EC),Striatum (ST), Putamen (PUT), Pallidum (PAL), Thalamus (TH), Substantia Nigra (SN), Periventricular Gray (PG), Locus coeruleus (LC), Medulla (ME), Cerebellum (granules) (CB), Cerebellum (molecular layer) (CB), Purkinje cells (PK).

 

2.3. PrPres Detection: Strain Discrimination by Proteinase K Sensitivity and Antibody Reactivity

 

We previously demonstrated that the technique that we developed for typing and classifying prion strains in small ruminants might also be used to discriminate L-BSE from c-BSE in experimentally infected macaques [21]. Briefly, this technique is based on the strain-dependent threshold of removal of the octapeptides under controlled conditions of proteolysis, in which this N-terminal region is highly resistant to proteolysis for scrapie and sporadic CJD prions, but weakly resistant for c-BSE and undetectable for L-BSE.

 

Figure 4. Electrophoretic analysis and differential sensitivity to proteolysis of PrPres in various experimental prion diseases of primates and transgenic mice overexpressing human PrP. PrPres from brain homogenates (primates or transgenic mice Tg650 overexpressing human PrP experimentally infected with cattle-adapted TME, L-BSE or c-BSE) were purified with high concentrations of proteinase K, and detected with monoclonal antibodies recognizing the octapeptide region (Saf-32) or the core (Sha-31) of the protein. The membrane blotted with Saf-32 was overexposed compared to the membrane blotted with Sha-31.

 

Under these experimental conditions, PrPres in both primates and Tg650 exposed to cattle-adapted TME behaved like PrPres derived from corresponding animals infected with L-BSE [21] (Figure 4). A 19 kDa non-glycosylated band was observed with the anti-core antibody Sha-31, with an equal distribution between mono- and diglycosylated bands. With the anti-octapeptide antibody Saf-32, almost no immunoreactivity was detectable for these animals. In parallel, c-BSE infected animals exhibited the expected features, including a 20 kDa non glycosylated band with Sha-31, predominance of diglycosylated band and a weak immunoreactivity with Saf-32 (only observable when overexposing the membrane), suggesting that c-BSE related PrPres is more resistant to proteolysis than L-BSE- or TME-related PrPres (the macaque infected with raccoon TME exhibited glycophoretic profiles and resistance to proteolysis resistance similar to the macaque infected with cattle TME, data not shown). We previously described the biochemical similarities between PrPres derived from L-BSE infected macaque and cortical MM2 sporadic CJD: those observations suggest a link between these two uncommon prion phenotypes in a primate model (it is to note that such a link has not been observed in other models less relevant from the human situation as hamsters or transgenic mice overexpressing ovine PrP [28]). We speculate that a group of related animal prion strains (L-BSE, c-BSE and TME) would have a zoonotic potential and lead to prion diseases in humans with a type 2 PrPres molecular signature (and more specifically type 2B for vCJD).

 

Strain signatures were also assessed in bioassays in transgenic mice overexpressing bovine PrP (tg110). Those mice were intracerebrally inoculated with cattle-adapted TME, L-BSE or c-BSE isolates issued from cattle, macaque or tg650 recipients (vCJD samples were also included as controls) (Figure 1). All the inoculated mice developed a TSE, with similar incubation periods whatever the source (cattle, primate, Tg650 mice or human), but related to the original prion strain: mean periods ranged from 216 to 233 days for cattle-adapted TME and from 226 to 238 days for L-BSE, while c-BSE led to longer incubation periods ranging from 309 to 362 days. This biochemical strain typing protocol was adapted (preferential use of Bar-233 antibody for protein core detection) and applied to Tg110 mice (Figure 5). The respective features (size of non glycosylated band, proportion of glycosylated forms, resistance of octapeptide regions to proteolysis) that were observed in primates and Tg650 mice for each original prion strain (cattle TME, L-BSE or c-BSE) were also observed in this model, regardless of the host from which the prion originated.

 

Figure 5. Electrophoretic analysis and differential sensitivity to proteolysis of PrPres in various experimental prion diseases of transgenic mice overexpressing bovine PrP. Transgenic mice Tg110 overexpressing bovine PrP were inoculated with brain tissue from cattle, primate, or Tg650 mice experimentally infected with cattle-adapted TME, L-BSE or c-BSE, or brain tissue from a vCJD patient. The brains were homogenized and PrPres was purified with high concentrations of proteinase K, and detected with monoclonal antibodies that recognize either the octapeptide region (Saf-32) or the core (Bar-233) of the protein. The membrane blotted with Saf-32 was overexposed compared to the membrane blotted with Bar-233.

 

3. Experimental Section

 

3.1. Ethics Statement

 

Primates and mice were housed and handled in accordance with the European Directive 2010/63 related to animal protection and welfare in research, under the constant internal surveillance of veterinarians. Animals were handled under anesthesia to limit stress, and euthanasia was performed for ethical reasons when animals lost autonomy.

 

3.2. Experimental Animals

 

Captive-bred 2-5 year-old male cynomolgus macaques (Macaca fascicularis) were provided by Noveprim (Mauritius), checked for the absence of common primate pathogens before importation, and handled in accordance to national guidelines. Transgenic mice overexpressing human (tg650 [23]) or bovine (tg110 [29]) PrP were internally bred at CEA (Fontenay-aux-Roses, France). Animals housed in level-3 animal care facilities (agreement numbers A 92-032-02 for animal care facilities, 92-189 for animal experimentation) were regularly examined at least once a week.

 

3.3. Experimental Inoculations

 

The TME inocula were derived from a second passage in cattle (#A263, [7]) or the first passage from mink to raccoon (#R5-6, [30]). The L-BSE inoculum (mix of brainstem and thalamus) was derived from an asymptomatic 15 year-old Italian Piemontese cow (#1088, [10]), and the c-BSE inocula were derived from infected UK cattle. Macaques and mice were intracerebrally (i.c.) inoculated with 1% or 10% brain homogenates in a 5% glucose solution.

 

3.4. Neuropathology and Immunohistochemistry

 

Tissues were fixed in formalin 4% for histological examination. Neuropathology and immunohistochemical detection of protease-resistant prion protein (PrPres) were performed on brain sections as previously described [21].

 

3.4. PrPres Analysis

 

PrP was purified according to the TeSeE purification protocol (Bio-Rad), in adapted conditions of proteolysis for strain discrimination as previously described [21], using Bar-233, Sha-31 or Saf-32 antibodies.

 

4. Conclusions

 

We have shown that cattle-adapted TME is the third cattle prion strain (joining classical and L-type BSE) to be transmissible both to non-human primates and transgenic mice overexpressing human PrP. However, the successful transmission of raccoon TME to primate, inducing a disease with similar features as cattle TME, extends this notion to TME-related strains independent of host origin. Pathological, biochemical and bioassay investigations converged to demonstrate the similarity between cattle-adapted TME and L-BSE. Together with previous experiments performed in ovinized and bovinized transgenic mice and hamsters [8,9] indicating similarities between TME and L-BSE, the data support the hypothesis that L-BSE could be the origin of the TME outbreaks in North America and Europe during the mid-1900s. The corollary of this notion is the longstanding existence of atypical bovine prion cases in those countries during the same period, if not earlier. Although the risk of L-BSE for public health must be further assessed through studies using the oral route of exposure before drawing definitive conclusions, these data underline the importance of a potential zoonotic risk of L-BSE in the management of consumer protection, particularly in the context of the current relaxation of European policy with respect to BSE.

 

Acknowledgments

 

The authors acknowledge Health Canada and the NIAID-NIH PO1 AI 77774-01 “Pathogenesis, Transmission and Detection of Zoonotic Prion Diseases” for funding parts of those experiments. The authors thanks J.-L. Villotte and V. Beringue for their generous gift of transgenic mice overexpressing human PrP, as well as Christophe Durand, Onofrio Bevilacqua and Sébastien Jacquin for the excellent daily care they gave to the animals.

 

Conflict of Interest

 

The CEA owns a patent covering the BSE diagnostic tests commercialized by the company Bio-Rad.

 

References

 

SNIP...

 

 


 

 


 

 

 

 

>>>We previously described the biochemical similarities between PrPres derived from L-BSE infected macaque and cortical MM2 sporadic CJD: those observations suggest a link between these two uncommon prion phenotypes in a primate model (it is to note that such a link has not been observed in other models less relevant from the human situation as hamsters or transgenic mice overexpressing ovine PrP [28]). We speculate that a group of related animal prion strains (L-BSE, c-BSE and TME) would have a zoonotic potential and lead to prion diseases in humans with a type 2 PrPres molecular signature (and more specifically type 2B for vCJD)<<<

 

 

 

2003 Singeltary Submission to FDA ;

 

 

Asante/Collinge et al have major findings on sporadic CJD, why in the hell is this not making big news in the USA? ($$$) the fact that with the new findings from Collinge et al, that BSE transmission to the 129-methionine genotype can lead to an alternate phenotype which is indistinguishable from type 2 PrPSc, the commonest sporadic CJD, i only ponder how many of the sporadic CJDs in the USA are tied to this alternate phenotype? these new findings are very serious, and should have a major impact on the way sporadic CJDs are now treated as opposed to the vCJD that was thought to be the only TSE tied to ingesting beef, in the medical/surgical arena. these new findings should have a major impact on the way sporadic CJD is ignored, and should now be moved to the forefront of research as with vCJD/nvCJD. the USA has many TSEs, the USA lacks sufficient testing for TSEs in cattle, and the USA still refuses to rapid TSE test USA cattle in sufficient numbers to find, when the late Dr. Richard Marsh had proven that mink had gone down with a TSE (TME), from being fed on 95%+ downer cattle.

 


 


 

 

From: Terry S. Singeltary Sr. [flounder@wt.net]

 

Sent: Tuesday, July 29, 2003 1:03 PM

 


 

Cc: ggraber@cvm.fda.gov; Linda.Grassie@fda.gov; BSE-L

 

Subject: Docket No. 2003N-0312 Animal Feed Safety System [TSS SUBMISSION TO DOCKET 2003N-0312]

 

Greetings FDA,

 

my name is Terry S. Singeltary Sr., i lost my mother to hvCJD (Heidenhain Variant Creutzfeldt Jakob Disease).

 

i would kindly like to comment on the proposed HACCP method of detecting and or preventing TSEs in the human/animal feed supply.

 

it seems to me by implementing something that was designed for Astronauts instead of cattle, something that the GAO has already stated is terribly flawed (HACCP), i find it very disturbing to continue to insist on refusing to use rapid TSE TESTING in sufficient numbers to find TSEs, as with other Countries that they too once thought they were BSE free. for example, it took Italy 1 MILLION rapid TSE tests since 2001 to find 102 cases of BSE. THE USA has only tested 48,000 cattle in the 14 years of surveillance. there is documented proof that indeed the USA cattle have been infected with a TSE for decades, but the FDA/USDA and other USA Gov. agencies continue to conveniently ignore these findings. YOU must not ignore what Richard Marsh found. Plus, you must not ignore Asante/Collinge new findings that BSE transmission to the 129-methionine genotype can lead to an alternate phenotype that is indistinguishable from type 2 PrPSc, the commonest _sporadic_ CJD. The USA has been feeding ruminant by-products back to cattle, deer, elk and sheep for decades, and TSEs in these species have been recycled for feed for decades in the USA. The rendering process here in the USA will not kill this agent. to implement any HACCP over massive rapid TSE testing is only prolonging the inevitable, and will only allow the agent to spread further. it is simply a band-aid approach to something that needs a tourniquet...

 


 

 

 

From: Terry S. Singeltary Sr. [flounder9@verizon.net]

 

Sent: Monday, July 24, 2006 1:09 PM

 

To: FSIS RegulationsComments

 

Subject: [Docket No. FSIS-2006-0011] FSIS Harvard Risk Assessment of Bovine Spongiform Encephalopathy (BSE)

 

Page 1 of 98

 

8/3/2006

 

Greetings FSIS,

 

I would kindly like to comment on the following ;

 

 


 

 

response to Singeltary et al ;

 


 

 


 

 

Monday, January 08, 2001 3:03 PM

 


 

 

 

A kind greetings from Bacliff, Texas !

 

I have often pondered if the whole damn mad cow follies started over here in the USA, and somehow, the USA shipped it over to the UK ?

 

It happened with S. Korea and CWD, via Canada. see ;

 

The disease was confirmed only in elk in the Republic of Korea in 2001, 2004 and 2005. Epidemiological investigations showed that CWD was introduced via importation of infected elk from Canada between 1994 and 1997.

 


 

 

 

but I still am not so sure that the mad cow follies did not start long ago right here in the USA i.e. Richard Marsh and deadstock downer cattle to those mink, and then the USA shipped it to hell and back. just pondering out loud here. ...tss

 

 

 

The exact same recipe for B.S.E. existed in the U.S. for years

 

and years. In reading over the Qualitative Analysis of BSE

 

Risk Factors-1, this is a 25 page report by the

 

USDA:APHIS:VS. It could have been done in one page. The

 

first page, fourth paragraph says it all;

 

"Similarities exist in the two countries usage of continuous

 

rendering technology and the lack of usage of solvents,

 

however, large differences still remain with other risk factors

 

which greatly reduce the potential risk at the national level."

 

Then, the next 24 pages tries to down-play the high risks of

 

B.S.E. in the U.S., with nothing more than the cattle to sheep

 

ratio count, and the geographical locations of herds and flocks.

 

That's all the evidence they can come up with, in the next 24

 

pages.

 

 Something else I find odd, page 16;

 

 "In the United Kingdom there is much concern for a specific

 

continuous rendering technology which uses lower

 

temperatures and accounts for 25 percent of total output. This

 

technology was _originally_ designed and imported from the

 

United States. However, the specific application in the

 

production process is _believed_ to be different in the two

 

countries."

 

 A few more factors to consider, page 15;

 

 "Figure 26 compares animal protein production for the two

 

countries. The calculations are based on slaughter numbers,

 

fallen stock estimates, and product yield coefficients. This

 

approach is used due to variation of up to 80 percent from

 

different reported sources. At 3.6 million tons, the United

 

States produces 8 times more animal rendered product than

 

the United Kingdom."

 

 "The risk of introducing the BSE agent through sheep meat and

 

bone meal is more acute in both relative and absolute terms in

 

the United Kingdom (Figures 27 and 28). Note that sheep

 

meat and bone meal accounts for 14 percent, or 61 thousand

 

tons, in the United Kingdom versus 0.6 percent or 22 thousand

 

tons in the United States. For sheep greater than 1 year, this is

 

less than one-tenth of one percent of the United States supply."

 

"The potential risk of amplification of the BSE agent through

 

cattle meat and bone meal is much greater in the United States

 

where it accounts for 59 percent of total product or almost 5

 

times more than the total amount of rendered product in the

 

United Kingdom."

 

 Considering, it would only take _one_ scrapie infected sheep

 

to contaminate the feed. Considering Scrapie has run rampant

 

in the U.S. for years, as of Aug. 1999, 950 scrapie infected

 

flocks. Also, Considering only one quarter spoonful of scrapie

 

infected material is lethal to a cow. Considering all this, the

 

sheep to cow ration is meaningless. As I said, it's 24 pages of

 

B.S.e.

 

To be continued...

 

Terry S. Singeltary Sr. P.O. Box 42 Bacliff, Texas USA

 

_____________________________________________________________________

 

 

 


 

 

snip...see full text ;

 

 

Monday, June 3, 2013

 

Unsuccessful oral transmission of scrapie from British sheep to cattle

 


 

 

Thursday, August 15, 2013

 

Stability properties of PrPSc from cattle with experimental transmissible spongiform encephalopathies: use of a rapid whole homogenate, protease-free assay

 


 

 

Sunday, July 21, 2013

 

Welsh Government and Food Standards Agency Wales Joint Public Consultation on the Proposed Transmissible Spongiform Encephalopathies (Wales) Regulations 2013 Singeltary Submission WG18417

 


 

 

 

Saturday, July 6, 2013

 

Small Ruminant Nor98 Prions Share Biochemical Features with Human Gerstmann-Sträussler-Scheinker Disease and Variably Protease-Sensitive Prionopathy

 

Research Article

 


 

 

 

Tuesday, July 21, 2009

 

Transmissible mink encephalopathy - review of the etiology

 


 

 

 

Saturday, December 01, 2007

 

Phenotypic Similarity of Transmissible Mink Encephalopathy in Cattle and L-type Bovine Spongiform Encephalopathy in a Mouse Model

 


 

 

 

Sunday, December 10, 2006

 

Transmissible Mink Encephalopathy TME

 


 


 

 

 

Thursday, March 29, 2012

 

atypical Nor-98 Scrapie has spread from coast to coast in the USA 2012

 

NIAA Annual Conference April 11-14, 2011San Antonio, Texas

 


 

 

 

Friday, July 26, 2013

 

Voluntary Scrapie Program USA UPDATE July 26, 2013 increase in FY 2013 is not statistically meaningful due to the sample size

 


 

 

 

Sunday, August 25, 2013

 

Prion2013 Chronic Wasting Disease CWD risk factors, humans, domestic cats, blood, and mother to offspring transmission

 


 

 

 

Friday, August 16, 2013

 

*** Creutzfeldt-Jakob disease (CJD) biannual update August 2013 U.K. and Contaminated blood products induce a highly atypical prion disease devoid of PrPres in primates

 


 

 

 

Sunday, August 11, 2013

 

Creutzfeldt-Jakob Disease CJD cases rising North America updated report August 2013

 

*** Creutzfeldt-Jakob Disease CJD cases rising North America with Canada seeing an extreme increase of 48% between 2008 and 2010

 


 

 

 

 

TSS

No comments:

Post a Comment