Saturday, February 11, 2012

Prion cross-species transmission efficacy is tissue dependent

Prion cross-species transmission efficacy is tissue dependent
Claire Williams, University of Cambridge School of Clinical Medicine, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0SP

Prions are proteinaceous infectious agents which result in fatal neurodegenerative disorders in a range of animals, including humans. Prions are misfolded forms of the ubiquitously expressed host protein PrPc. When PrPc becomes misfolded it is known as PrPsc and forms macromolecular complexes which are deposited in the brain, and sometimes in lymphoid tissue. When PrPsc is introduced into a healthy animal it induces the transformation of the normal PrPc into the misfolded PrPsc form. Such transmission does occur between different species, for example the transmission of bovine spongiform encephalopathy (BSE) into humans. However such transmission is much less efficient than transmission within a species. It is hypothesised that the cross-species transmission of prions is restricted due to steric incompatibility between the infecting PrPsc and the host PrPc. A paper published in Science this week suggests that the efficiency of cross-species prion transmission may actually vary between tissues and be higher than previously thought (1).

Béringue et al. looked at the transmission of prions from elk, hamsters and cattle into mice which had been genetically engineered to express either the sheep or human version of PrPc. The mice were infected by intra-cerebral injection and euthanised at regular intervals post exposure. The presence of PrPsc in the brain and the spleen of these animals was assessed by immunoblotting. Unsurprisingly given the cross-species barriers involved, none of the mice developed neurological disease during the study and only small numbers of animals had detectable PrPsc in their brains. However, many more animals had PrPsc detected in their spleens. Using the experiment looking at the transmission of BSE into mice with human PrPc as an example, 7% of animals had detectable PrPsc in brain tissue, compared with detection of the abnormal protein in the spleens of 63% of the animals.

These results suggest that the spleen is much more permissive than the brain to foreign prions. This could have significant implications for human medicine. To date around 200 individuals have developed variant Creutzfeldt-Jakob disease as a result of infection with BSE, however there has been much discussion about people potentially being silent carriers of the infection. This study, along with others looking at the prevalence of PrPsc in archived appendix tissue, raises the possibility that BSE exposure led to lymphoid tissue colonisation in more individuals than developed, or will develop, neuroinvasive disease. This has important public health implications with regards potential human to human spread of prions through organ transplantation, surgical instruments etc. As the prion is now adapted to humans, it is possible that the risk of lethal infection is higher than seen with cattle to human transmission.

References:

1. Béringue V, Herzog L, Jaumain E, Reine F, Sibille P, Le Dur A, Vilotte J-L, Laude H. Facilitated Cross-Species Transmission of Prions in Extraneural Tissue. Science 2012 Jan;335(6067):472 -475. doi:10.1126/science.1215659

Story image from Wikimedia Commons.

http://www.cambridgemedicine.org/news/1328879145




Thursday, January 26, 2012

The Risk of Prion Zoonoses

Science 27 January 2012: Vol. 335 no. 6067 pp. 411-413 DOI: 10.1126/science.1218167

http://transmissiblespongiformencephalopathy.blogspot.com/2012/01/risk-of-prion-zoonoses.html





Thursday, January 26, 2012

Facilitated Cross-Species Transmission of Prions in Extraneural Tissue

Science 27 January 2012: Vol. 335 no. 6067 pp. 472-475 DOI: 10.1126/science.1215659

http://transmissiblespongiformencephalopathy.blogspot.com/2012/01/facilitated-cross-species-transmission.html





Sunday, January 22, 2012

Chronic Wasting Disease CWD cervids interspecies transmission

http://chronic-wasting-disease.blogspot.com/2012/01/chronic-wasting-disease-cwd-cervids.html







> > > Can the disease be transfered to cattle?


YES, and with an attack rate of 86%. this was done in the lab, and not under natural conditions, but with a second strain of CWD emerging i.e. the ‘WISCONSIN STRAIN’, there is much concern for the _potential_ for an atypical CWD strain that would naturally transmit to cattle. please see ;





CWD to cattle figures CORRECTION



Greetings,



I believe the statement and quote below is incorrect ;



"CWD has been transmitted to cattle after intracerebral inoculation, although the infection rate was low (4 of 13 animals [Hamir et al. 2001]). This finding raised concerns that CWD prions might be transmitted to cattle grazing in contaminated pastures."

Please see ;

Within 26 months post inoculation, 12 inoculated animals had lost weight, revealed abnormal clinical signs, and were euthanatized. Laboratory tests revealed the presence of a unique pattern of the disease agent in tissues of these animals. These findings demonstrate that when CWD is directly inoculated into the brain of cattle, 86% of inoculated cattle develop clinical signs of the disease.



http://www.ars.usda.gov/research/publications/publications.htm?seq_no_115=194089




" although the infection rate was low (4 of 13 animals [Hamir et al. 2001]). "




shouldn't this be corrected, 86% is NOT a low rate. ...




kindest regards,

Terry S. Singeltary Sr. P.O. Box 42 Bacliff, Texas USA 77518





Thank you!

Thanks so much for your updates/comments. We intend to publish as rapidly as possible all updates/comments that contribute substantially to the topic under discussion.

http://cshperspectives.cshlp.org/letters/submit



re-Prions David W. Colby1,* and Stanley B. Prusiner1,2 + Author Affiliations

1Institute for Neurodegenerative Diseases, University of California, San Francisco, San Francisco, California 94143 2Department of Neurology, University of California, San Francisco, San Francisco, California 94143 Correspondence: stanley@ind.ucsf.edu

http://cshperspectives.cshlp.org/content/3/1/a006833.full.pdf+html




Mule deer, white-tailed deer, and elk have been reported to develop CWD. As the only prion disease identified in free-ranging animals, CWD appears to be far more communicable than other forms of prion disease. CWD was first described in 1967 and was reported to be a spongiform encephalopathy in 1978 on the basis of histopathology of the brain. Originally detected in the American West, CWD has spread across much of North America and has been reported also in South Korea. In captive populations, up to 90% of mule deer have been reported to be positive for prions (Williams and Young 1980). The incidence of CWD in cervids living in the wild has been estimated to be as high as 15% (Miller et al. 2000). The development of transgenic (Tg) mice expressing cervid PrP, and thus susceptible to CWD, has enhanced detection of CWD and the estimation of prion titers (Browning et al. 2004; Tamgüney et al. 2006). Shedding of prions in the feces, even in presymptomatic deer, has been identified as a likely source of infection for these grazing animals (Williams and Miller 2002; Tamgüney et al. 2009b). CWD has been transmitted to cattle after intracerebral inoculation, although the infection rate was low (4 of 13 animals [Hamir et al. 2001]). This finding raised concerns that CWD prions might be transmitted to cattle grazing in contaminated pastures.




snip...




http://cshperspectives.cshlp.org/content/3/1/a006833.full.pdf+html




please see CWD potential to humans here ;

http://betaamyloidcjd.blogspot.com/2011/01/enlarging-spectrum-of-prion-like.html






MARCH 1, 2011



UPDATED CORRESPONDENCE FROM AUTHORS OF THIS STUDY I.E. COLBY, PRUSINER ET AL, ABOUT MY CONCERNS OF THE DISCREPANCY BETWEEN THEIR FIGURES AND MY FIGURES OF THE STUDIES ON CWD TRANSMISSION TO CATTLE ;



----- Original Message -----

From: David Colby

To: flounder9@verizon.net

Cc: stanley@XXXXXXXX

Sent: Tuesday, March 01, 2011 8:25 AM

Subject: Re: FW: re-Prions David W. Colby1,* and Stanley B. Prusiner1,2 + Author Affiliations

Dear Terry Singeltary,

Thank you for your correspondence regarding the review article Stanley Prusiner and I recently wrote for Cold Spring Harbor Perspectives. Dr. Prusiner asked that I reply to your message due to his busy schedule. We agree that the transmission of CWD prions to beef livestock would be a troubling development and assessing that risk is important. In our article, we cite a peer-reviewed publication reporting confirmed cases of laboratory transmission based on stringent criteria. The less stringent criteria for transmission described in the abstract you refer to lead to the discrepancy between your numbers and ours and thus the interpretation of the transmission rate. We stand by our assessment of the literature--namely that the transmission rate of CWD to bovines appears relatively low, but we recognize that even a low transmission rate could have important implications for public health and we thank you for bringing attention to this matter.

Warm Regards, David Colby

--

David Colby, PhDAssistant ProfessorDepartment of Chemical EngineeringUniversity of Delaware



====================END...TSS==============



http://betaamyloidcjd.blogspot.com/2011/01/enlarging-spectrum-of-prion-like.html





UPDATED DATA ON 2ND CWD STRAIN

Wednesday, September 08, 2010

CWD PRION CONGRESS SEPTEMBER 8-11 2010

http://chronic-wasting-disease.blogspot.com/2010/09/cwd-prion-2010.html





Wednesday, January 5, 2011

ENLARGING SPECTRUM OF PRION-LIKE DISEASES Prusiner Colby et al 2011

Prions

David W. Colby1,* and Stanley B. Prusiner1,2

http://betaamyloidcjd.blogspot.com/2011/01/enlarging-spectrum-of-prion-like.html





PLEASE NOTE ON SECOND PASSAGE, ALL CATTLE 100% HAD CONTRACTED CWD ;



When brainstems of CWD-infected cattle were analysed by WB for the presence of PrPres, only three of six samples were found to be positive (Table 1). In contrast, all samples from the midbrain area were positive by this technique (Table 1; Fig. 5). It was noteworthy, however, that both brainstem and midbrain sections of all animals infected with CWD gave positive IHC results (Table 1) and a positive WB was associated with strong IHC labelling. This may indicate that the IHC procedure is more sensitive than the WB method for cattle-passaged CWD.



http://ddr.nal.usda.gov/bitstream/10113/34009/1/IND43787291.pdf







EFSA Journal 2011 The European Response to BSE: A Success Story

This is an interesting editorial about the Mad Cow Disease debacle, and it's ramifications that will continue to play out for decades to come ;

Monday, October 10, 2011

EFSA Journal 2011 The European Response to BSE: A Success Story

snip...

EFSA and the European Centre for Disease Prevention and Control (ECDC) recently delivered a scientific opinion on any possible epidemiological or molecular association between TSEs in animals and humans (EFSA Panel on Biological Hazards (BIOHAZ) and ECDC, 2011). This opinion confirmed Classical BSE prions as the only TSE agents demonstrated to be zoonotic so far but the possibility that a small proportion of human cases so far classified as "sporadic" CJD are of zoonotic origin could not be excluded. Moreover, transmission experiments to non-human primates suggest that some TSE agents in addition to Classical BSE prions in cattle (namely L-type Atypical BSE, Classical BSE in sheep, transmissible mink encephalopathy (TME) and chronic wasting disease (CWD) agents) might have zoonotic potential.

snip...

http://www.efsa.europa.eu/en/efsajournal/pub/e991.htm?emt=1



http://www.efsa.europa.eu/en/efsajournal/doc/e991.pdf



see follow-up here about North America BSE Mad Cow TSE prion risk factors, and the ever emerging strains of Transmissible Spongiform Encephalopathy in many species here in the USA, including humans ;

http://transmissiblespongiformencephalopathy.blogspot.com/2011/10/efsa-journal-2011-european-response-to.html



Wednesday, March 31, 2010

Atypical BSE in Cattle

To date the OIE/WAHO assumes that the human and animal health standards set out in the BSE chapter for classical BSE (C-Type) applies to all forms of BSE which include the H-type and L-type atypical forms. This assumption is scientifically not completely justified and accumulating evidence suggests that this may in fact not be the case. Molecular characterization and the spatial distribution pattern of histopathologic lesions and immunohistochemistry (IHC) signals are used to identify and characterize atypical BSE. Both the L-type and H-type atypical cases display significant differences in the conformation and spatial accumulation of the disease associated prion protein (PrPSc) in brains of afflicted cattle. Transmission studies in bovine transgenic and wild type mouse models support that the atypical BSE types might be unique strains because they have different incubation times and lesion profiles when compared to C-type BSE. When L-type BSE was inoculated into ovine transgenic mice and Syrian hamster the resulting molecular fingerprint had changed, either in the first or a subsequent passage, from L-type into C-type BSE.

In addition, non-human primates are specifically susceptible for atypical BSE as demonstrated by an approximately 50% shortened incubation time for L-type BSE as compared to C-type. Considering the current scientific information available, it cannot be assumed that these different BSE types pose the same human health risks as C-type BSE or that these risks are mitigated by the same protective measures.

This study will contribute to a correct definition of specified risk material (SRM) in atypical BSE. The incumbent of this position will develop new and transfer existing, ultra-sensitive methods for the detection of atypical BSE in tissue of experimentally infected cattle.

http://www.prionetcanada.ca/detail.aspx?menu=5&dt=293380&app=93&cat1=387&tp=20&lk=no&cat2





Thursday, August 12, 2010

Seven main threats for the future linked to prions

First threat

The TSE road map defining the evolution of European policy for protection against prion diseases is based on a certain numbers of hypotheses some of which may turn out to be erroneous. In particular, a form of BSE (called atypical Bovine Spongiform Encephalopathy), recently identified by systematic testing in aged cattle without clinical signs, may be the origin of classical BSE and thus potentially constitute a reservoir, which may be impossible to eradicate if a sporadic origin is confirmed.

***Also, a link is suspected between atypical BSE and some apparently sporadic cases of Creutzfeldt-Jakob disease in humans. These atypical BSE cases constitute an unforeseen first threat that could sharply modify the European approach to prion diseases.

Second threat

snip...

http://www.neuroprion.org/en/np-neuroprion.html



Rural and Regional Affairs and Transport References Committee

The possible impacts and consequences for public health, trade and agriculture of the Government's decision to relax import restrictions on beef Final report June 2010

2.66 Dr Fahey also told the committee that in the last two years a link has been established between forms of atypical CJD and atypical BSE. Dr Fahey said that: They now believe that those atypical BSEs overseas are in fact causing sporadic Creutzfeldt-Jakob disease. They were not sure if it was due to mad sheep disease or a different form. If you look in the textbooks it looks like this is just arising by itself. But in my research I have a summary of a document which states that there has never been any proof that sporadic Creutzfeldt-Jakob disease has arisen de novo-has arisen of itself. There is no proof of that. The recent research is that in fact it is due to atypical forms of mad cow disease which have been found across Europe, have been found in America and have been found in Asia. These atypical forms of mad cow disease typically have even longer incubation periods than the classical mad cow disease.50

http://www.aph.gov.au/senate/committee/rrat_ctte/mad_cows/report/report.pdf





And last but not least, similarities of PrPres between Htype BSE and human prion diseases like CJD or GSS have been put forward [10], as well as between L-type BSE and CJD [17]. These findings raise questions about the origin and inter species transmission of these prion diseases that were discovered through the BSE active surveillance.

full text 18 pages ;

http://www.vetres.org/index.php?option=article&access=standard&Itemid=129&url=/articles/vetres/pdf/2008/04/v07232.pdf





please see full text ;

http://bse-atypical.blogspot.com/2008/06/review-on-epidemiology-and-dynamics-of.html





[Terry S. Singeltary Sr. has added the following comment:

"According to the World Health Organisation, the future public health threat of vCJD in the UK and Europe and potentially the rest of the world is of concern and currently unquantifiable. However, the possibility of a significant and geographically diverse vCJD epidemic occurring over the next few decades cannot be dismissed.

http://whqlibdoc.who.int/publications/2003/9241545887.pdf





Terry S. Singeltary Sr. has added the following comment:

"According to the World Health Organisation, the future public health threat of vCJD in the UK and Europe and potentially the rest of the world is of concern and currently unquantifiable. However, the possibility of a significant and geographically diverse vCJD epidemic occurring over the next few decades cannot be dismissed.

The key word here is diverse. What does diverse mean? If USA scrapie transmitted to USA bovine does not produce pathology as the UK c-BSE, then why would CJD from there look like UK vCJD?"

http://www.promedmail.org/direct.php?id=20100405.1091







When L-type BSE was inoculated into ovine transgenic mice and Syrian hamster the resulting molecular fingerprint had changed, either in the first or a subsequent passage, from L-type into C-type BSE. In addition, non-human primates are specifically susceptible for atypical BSE as demonstrated by an approximately 50% shortened incubation time for L-type BSE as compared to C-type. Considering the current scientific information available, it cannot be assumed that these different BSE types pose the same human health risks as C-type BSE or that these risks are mitigated by the same protective measures.




This study will contribute to a correct definition of specified risk material (SRM) in atypical BSE. The incumbent of this position will develop new and transfer existing, ultra-sensitive methods for the detection of atypical BSE in tissue of experimentally infected cattle.



http://www.prionetcanada.ca/detail.aspx?menu=5&dt=293380&app=93&cat1=387&tp=20&lk=no&cat2







Saturday, June 25, 2011



Transmissibility of BSE-L and Cattle-Adapted TME Prion Strain to Cynomolgus Macaque




"BSE-L in North America may have existed for decades"



http://transmissiblespongiformencephalopathy.blogspot.com/2011/06/transmissibility-of-bse-l-and-cattle.html







Over the next 8-10 weeks, approximately 40% of all the adult mink on the farm died from TME.

snip...

The rancher was a ''dead stock'' feeder using mostly (>95%) downer or dead dairy cattle...



http://web.archive.org/web/20030516051623/http://www.bseinquiry.gov.uk/files/mb/m09/tab05.pdf





Thursday, February 09, 2012

50 GAME FARMS IN USA INFECTED WITH CHRONIC WASTING DISEASE

snip...



Dr. Michael Coulthart, et al, Public Health Agency of Canada



- although not occurring to date, he estimates that report of just one probable case of human CWD could trigger a public health crisis in North America.


- epidemiological studies so far indicate the probability is very slight, however, prion agents and their transmission properties are highly mutable and adaptable and the possibility can not be ruled out.



- suggests those involved in human prion disease surveillance should consider the possibility of human CWD and develop a readiness to deal with it.





snip...




http://chronic-wasting-disease.blogspot.com/2012/02/50-game-farms-to-date-in-usa-infected.html









Saturday, March 5, 2011

MAD COW ATYPICAL CJD PRION TSE CASES WITH CLASSIFICATIONS PENDING ON THE RISE IN NORTH AMERICA



http://transmissiblespongiformencephalopathy.blogspot.com/2011/03/mad-cow-atypical-cjd-prion-tse-cases.html





Friday, February 10, 2012



Creutzfeldt-Jakob disease (CJD) biannual update (2012/1) potential iatrogenic (healthcare-acquired) exposure to CJD, and on the National Anonymous Tonsil Archive



http://creutzfeldt-jakob-disease.blogspot.com/2012/02/creutzfeldt-jakob-disease-cjd-biannual.html





layperson



TSS

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