Thursday, December 29, 2011

Aerosols An underestimated vehicle for transmission of prion diseases?

Aerosols

 An underestimated vehicle for transmission of prion diseases?


 Lothar Stitz1,* and Adriano Aguzzi2


 1Institute of Immunology; Friedrich-Loeffler-Institut; Tübingen, Germany; 2Institute of Neuropathology; University of Zürich; Zürich, Switzerland


 We and others have recently reported that prions can be transmitted to mice via aerosols. These reports spurred a lively public discussion on the possible public-health threats represented by prion-containing aerosols. Here we offer our view on the context in which these findings should be placed. On the one hand, the fact that nebulized prions can transmit disease cannot be taken to signify that prions are airborne under natural circumstances. On the other hand, it appears important to underscore the fact that aerosols can originate very easily in a broad variety of experimental and natural environmental conditions. Aerosols are a virtually unavoidable consequence of the handling of fluids; complete prevention of the generation of aerosols is very difficult. While prions have never been found to be transmissible via aerosols under natural conditions, it appears prudent to strive to minimize exposure to potentially prion-infected aerosols whenever the latter may arise—for example in scientific and diagnostic laboratories handling brain matter, cerebrospinal fluids and other potentially contaminated materials, as well as abattoirs. Equally important is that prion biosafety training be focused on the control of, and protection from, prion-infected aerosols.


 Prions, the causative agents of transmissible spongiform encephalopathies, can be undoubtedly propagated from one individual organism to another. The specific routes of prion transmission have been subjected to intensive studies over the past two decades. Incidental and iatrogenic transmission has occurred through the intracerebral route in the case of Dura mater implants1 and the parenteral route in the case of contaminated pituitary hormones.2 In addition, the Bovine Spongiform Encephalopathy (BSE) disaster has provided grim evidence that prion can be transmitted enterally as well. Experimental transmission of prions has been routinely achieved via intraperitoneal and intravenous injection3,4 but also through more exotic routes such as intralingual,5 intranerval6 and conjunctival inoculation7 and via the nasal cavity.8


 In all prion disease paradigms studied so far the propagation, accumulation and dissemination of the prion protein has been mostly shown to depend on a functional immune system.9-12 This dependence of prion pathogenesis on the lymphoid compartment, however, is only true for peripheral routes of infection—whereas direct inoculation into the brain does not require any components of the adaptive or innate immune system.


 B cells in secondary lymphoid organs have been shown to be of importance for the neuroinvasion of the prion protein; in contrast, B lymphocytes in the blood do not appear to play a crucial role.13-15


 A special role in prion pathogenesis can be assigned to follicular dendritic cells (FDC). The generation, maturation and function of FDC are dependent on cytokines and chemokines predominantly synthesized and secreted by B lymphocytes. Consistently with this role of B cells in prion pathogenesis, B-cell deficient mice show a significantly impaired prion replication due to severely impaired maturation of FDCs.16 Other soluble and membrane-bound immune mediators such as lymphotoxin heterotrimers and TNFa17,18 as well as components of the complement system,19,20 play an important role in prion pathogenesis.


 While prions mostly reside in tissues, prion infectivity has also been detected in a variety of body fluids including cerebrospinal fluid,21 blood,22 saliva,23 milk24 and urine.25 Although shedding of prions may occur constitutively from these secretions and excretions, many of the latter phenomena are enhanced by chronic inflammatory processes such as granulomas26 and follicular infiltrates,27 which trigger the maturation of lymphotoxin-dependent, prion-replicating cells.26 The presence of prions in fluids begs the question whether nebulization, and subsequent inhalation, of such fluids may trigger prion infections.


 Aerosols are finely dispersed particles originating from solid material or liquid using air or other gases as carriers. Natural examples of aerosols include dust (e.g., volcano ashes), smoke, haze and sprays (e.g., sneezing or sea water sprays from breaking waves). Aerosols might be formally categorized as primary or secondary, with primary aerosols being generated in mechanical or thermal processes e.g., by whirling up, impact on surfaces, or burning, whereas secondary aerosols are generated during chemical reactions or by using condensation nuclei.


 Primary aerosols play an important role in microbiology since they can act as efficacious vehicles for pollen, spores, algae, fungi, bacteria and viruses. Of medical importance are also dandruff, fragments of fur, hairs or skin and mites, which can all function as allergens and trigger allergic asthma.


 Moreover, aerosols are excellent vehicles for the transportation of drugs into the respiratory tract. The size of the individual droplets is crucial in specifying the target organs of aerosol. Particle sized 3–10 μm are generally deposited in the nasal cavity and in the throat, whereas smaller particles (e.g., 1 μm) tend to deposit within the lower airways. In rodents pulmonary deposition can reach 10%.28,29 In humans, particles of 5 μm may reach the lung if inhaled orally, but deposition in the alveolar compartment after inhaling via the nose is highly unlikely.28,29 For the reasons discussed above, we have become interested in exploring the transmission potential of aerosol-borne prions.


 Indeed, we found that mouse scrapie can be efficiently transmitted via aerosols.30 In addition to results obtained by exposure to aerosols, we found that mice developed prion infections when inoculated intranasally.


 Interestingly, this route of transmission was entirely independent on immune cells as shown by challenging various transgenic mouse strains lacking defined functions of the immune system.


 Well-known examples of transmission of pathogens via aerosols are infections by respiratory viruses (e.g., influenza viruses, adenoviruses, rhinoviruses, coronaviruses) and bacterial diseases (e.g., legionellosis, pneumonic plague by Yersinia pestis, Q-fever by Coxiella burnettii, anthrax) and fungal diseases (particularly aspergillosis and candidosis). In stark contrast, aerosols have historically never been regarded as potential vectors for prion diseases— although very little data existed in favor or against this possibility. This attitude goes along with the implicit “conventional wisdom” that prions are not airborne diseases. However, the concept of “airborne disease” in all the bacterial, fungal and viral examples quoted above, encompasses three distinct phases: (1) release of the infectious agent into aerosols by an infected donor, (2) uptake by a healthy recipient and (3) establishment of disease. It is self-evident that little or no natural transmission between individuals will be observed if any one of these three steps is inefficient. The epidemiological evidence from human prion diseases seems to indicate, albeit indirectly, that step 1 does not occur in CJD patients—inter alia because there is a dearth of evidence of proximity clustering of sCJD.31 In the case of CWD the situation may be different since saliva and droppings, which might plausibly give rise to powerful aerosols under a variety of conditions, were found to harbor infectivity. Finally, milk from sheep affected by mastitis can carry scrapie infectivity and—again—could conceivably give rise to aerosols. Since both CWD and sheep scrapie can efficiently spread horizontally within animal collectives, it is extremely appealing to speculate whether aerosols may play a role in said transmission.


 In natural scrapie in sheep horizontal transmission of prion diseases has been long thought to arise from placental contamination. However, in mice suffering from nephritis prion infectivity is shed with the urine.25 Furthermore, sheep having a mastitis can transmit infectious prions with milk.32


 In Chronic Wasting disease (CWD) of deer several careful studies have been performed that, together with our present finding, depose in favor of airborne transmission in this naturally occurring disease. Indeed, CWD prions can be transmitted experimentally via aerosol and the nasal route to transgenic cervidized mice.33 Although no anecdotal or epidemiological evidence has come forward that airborne transmission may be important for the spread of CWD, several lines of thought suggest that this possibility is not implausible. In deer, prions have been detected in urine, saliva, feces and blood of diseased animals. Moreover, it was claimed that pathological prion protein could be recovered from the environmental water in an endemic area.34 Since all fluids can act as sources for the generation of aerosols, any of the body fluids mentioned above may represent the point of origin for airborne transmission of CWD prions.


 In this context, also the presence of infectious prions in blood of patients should be mentioned which was demonstrated by the transmission of vCJD by blood transfusions.35,36 The growing body of evidence that prion transmission can be airborne—at least under certain conditions—dictates that the release of potentially contaminated aerosols should be avoided under all circumstances. In this context it is mandatory that reliable precautions be defined and followed in scientific and diagnostic laboratories. In particular, it is self-evident that safety cabinets should be used while processing brain and nerve tissue (or any other potentially contaminated tissue) of man and animals suspected with prion disease. Our experience shows that this necessity is generally very well-understood by prion scientists.


 A further stone of contention relates to the biosafety level of the laboratory environment. Because prions were hitherto considered not be airborne, so far no specific regulations have been implemented. As a consequence, prion laboratories have been mostly required to adhere to the category “BSL3**.” While it is understood that the airborne transmission of prions has thus far only been observed under extreme conditions, we feel that it is in order to critically reassess biosafety regulations in the light of the recent discoveries. In particular, one might consider implementing more stringent measures towards protecting workers within diagnostic and scientific laboratories from aerosols.


 The situation in slaughterhouses and plants handling potentially contaminated offal may be even more problematic. Although regulations in slaughterhouses dictate the use of protecting glasses and masks or, alternatively, visors the use of personal protecting equipment should be rigorously controlled. In addition, high-pressure cleaning devices produce massive aerosols and should be strictly avoided in areas of slaughterhouses where prion-containing material may be processed. Regulations concerning cleaning of heads from slaughtered animals do pay attention to aerosol avoidance, e.g., by allowing only water hoses without pressure.


 A case in point is the severe neurological syndrome arising in swine abattoir workers.37 Here, an immune-mediated polyradiculoneuropathy was reported to be related to a process using high-pressure fluids to remove the brains of swine.37 During this process, high amounts of swine brain tissue became aerosolized and were inhaled and/or gained access to the respiratory tract mucosa of abattoir workers, resulting in immunization with myelin constituents akin to experimental autoimmune encephalitis (EAE). Although significant physiological differences exist concerning breathing, where humans are regarded as mouth breathers and mice as nose breathers, many people indeed show nose breathing under no or only moderate body burden. Therefore, results obtained in mouse experiments might also be extrapolated to a considerable extent to the situation in man.


 In this context it is of importance to stress again that aerosols might be generated under various conditions and represent a normal entity of the environment in a variety of daily life situations.


 In our studies of airborne transmission of prion protein in mice30 we took advantage of the fact that mice breathe exclusively through their nostrils38,39 and therefore could be exposed in groups to aerosolized brain suspensions. Using this system, it was possible to vary both time of exposure as well as concentration of the prion load in the aerosol. We were surprised to discover that exposure times as short as 1 min were sufficient to achieve high attack rates. By extending the time of exposure it became obvious that incubation times were shortened. A possible alternative route of infection via the cornea or the conjunctiva was extremely unlikely, since newborn mice, whose eyelids were still closed, could also be infected. These findings show that the aerogenic transmission of prions is very efficient.


 But how do prions spread from the airways to the brain? Peripheral replication of prions in the lymphoid system—a characteristic of most other peripheral routes of transmission—appeared to be dispensable. Instead, the results argue for a direct pathway of brain invasion. One anatomical peculiarity of the nasal cavity is the “area cribriformis” of the olfactory epithelium. Here the olfactory bulb sprouts axons of olfactory receptor neurons passing through the cribriform plate of the ethmoidal bone to reach the olfactory mucosa where olfactory cilia extend representing non-myelinated nerve endings. Thus, open nerve endings are located in the nasal cavity through which aerosolized infectious prions might get access to the brain. In this context it is noteworthy that pathological prion protein was found in the olfactory cilia and basal cells of the olfactory mucosa of sCJD patients, as well as in the olfactory bulb and olfactory tract.40,41 However, it was hitherto never clearly documented that olfactory receptor neurons represent an entry site for infectious prions; this might also be due to the sensitivity threshold of detection assays.


 In conclusion, aerosols can infect mice with a surprisingly high efficiency. Just how important a role is played by this newly recognized pathway of spread in natural transmission is, as of now, unclear and in need of further studies. Although it was not identified as a route of infection in epidemiological studies thus far, the worryingly high attack rate suggests that we would be well-advised to carefully avoid the inhalation of aerosols from prion-containing materials.


 Key words: prion, prion transmission, scrapie, chronic wasting diseases, CWD, Creutzfeldt-Jacob-disease, CJD, TSE, aerosol, pathogens, allergens Submitted: 05/19/11 Accepted: 06/09/11 DOI: 10.4161/pri.5.3.16851 *Correspondence to: Lothar Stitz or Adriano Aguzzi; Email: lothar.stitz@fli.bund.de or adriano.aguzzi@usz.ch


 References 1. Aguzzi A, Calella AM. Prions: protein aggregation and infectious diseases. Physiol Rev 2009; 89:1105-52. 2. Brown P, Gajdusek DC, Gibbs CJ Jr, Asher DM. Potential epidemic of Creutzfeldt-Jakob disease from human growth hormone therapy. N Engl J Med 1985; 313:728-31. 3. Kimberlin RH, Walker CA. Pathogenesis of mouse scrapie: dynamics of agent replication in spleen, spinal cord and brain after infection by different routes. J Comp Pathol 1979; 89:551-62. 4. Petsch B, Müller-Schiffmann A, Lehle A, Zirdum E, Prikulis I, Kuhn F, et al. Biological effects and use of PrPSc- and PrP-specific antibodies generated by immunizing with purified full length native mouse prions. J Virol 2011; 85:4538-46; PMID: 21345946. 5. Mulcahy ER, Bartz JC, Kincaid AE, Bessen RA. Prion infection of skeletal muscle cells and papillae in the tongue. J Virol 2004; 78:6792-8. 6. Glatzel M, Aguzzi A. PrP(C) expression in the peripheral nervous system is a determinant of prion neuroinvasion. J Gen Virol 2000; 81:2813-21. 7. Scott JR, Foster JD, Fraser H. Conjunctival instillation of scrapie in mice can produce disease. Vet Microbiol 1993; 34:305-9. 8. Kincade AE, Bartz JC. The nasal cavity is a route for prion infection in hamsters. J Virol 2007; 81:4482-91. 9. Klein MA, Frigg R, Flechsig E, Raeber AJ, Kalinke U, Bluethmann H, et al. A crucial role for B cells in neuroinvasive scrapie. Nature 1997; 390:687-90. 10. Klein MA, Kaeser PS, Schwarz P, Weyd H, Xenarios I, Zinkernagel RM, et al. Complement facilitates early prion pathogenesis. Nat Med 2001; 7:488-92. 11. Blättler T, Brandner S, Raeber AJ, Klein MA, Voigtländer T, Weissmann C, et al. PrP-expressing tissue required for transfer of scrapie infectivity from spleen to brain. Nature 1997; 389:69-73. 12. Raeber AJ, Sailer A, Hegyi I, et al. Ectopic expression of prion protein (PrP) in T lymphocytes or hepatocytes of PrP knockout mice is insufficient to sustain prion replication. Proc Natl Acad Sci USA 1999; 96:3987-92. 13. Klein MA, Frigg R, Raeber AJ, Flechsig E, Hegyi I, Zinkernagel RM, et al. PrP expression in B lymphocytes is not required for prion neuroinvasion. Nat Med 1998; 4:1429-33. 14. Raeber AJ, Klein MA, Frigg R, Flechsig E, Aguzzi A, Weissmann C, et al. PrP-dependent association of prions with splenic but not circulating lymphocytes of scrapie-infected mice. EMBO J 1999; 18:2702-6. 15. Montrasio F, Cozzio A, Flechsig E, Rossi D, Klein MA, Rülicke T, et al. B lymphocyte-restricted expression of prion protein does not enable prion replication in prion protein knockout mice. Proc Natl Acad Sci USA 2001; 98:4034-7. 16. Klein MA, Frigg R, Flechsig E, Raeber AJ, Kalinke U, Bluethmann H, et al. A crucial role for B cells in neuroinvasive scrapie. Nature 1997; 390:687-90. 17. Prinz M, Huber G, Macpherson AJ, Heppner FL, Glatzel M, Eugster HP, et al. Oral prion infection requires normal numbers of Peyer’s Patches but not of enteric lymphocytes. Am J Pathol 2003; 162:1103-11. 18. Prinz M, Montrasio F, Klein MA, Schwarz P, Priller J, Odermatt B, et al. Lymph nodal prion replication and neuroinvasion in mice devoid of follicular dendritic cells. Proc Natl Acad Sci USA 2002; 99:919-24.


 19. Klein MA, Kaeser PS, Schwarz P, Weyd H, Xenarios I, Zinkernagel RM, et al. Complement facilitates early prion pathogenesis. Nat Med 2001; 7:488-92. 20. Zabel MD, Heikenwalder M, Prinz M, Arrighi I, Schwarz P, Kranich J, et al. Stromal complement receptor CD21/35 facilitates lymphoid prion colonization and pathogenesis. J Immunol 2007; 179:6144-52. 21. Brown P, Gibbs CJ, Rodgers-Johnson P, Asher DM, Sulima MP, Bacote A, et al. Human spongiform encephalopathy: the National Institutes of Health series of 300 cases of experimentally transmitted disease. Ann Neurol 1994; 35:513-29. 22. Clarke MC, Haig DA. Presence of the transmissible agent of scrapie in the serum of affected mice and rats. Vet Rec 1967; 80:504. 23. Mathiason CK, Powers JG, Dahmes SJ, Osborn DA, Miller KV, Warren RJ, et al. Infectious prions in the saliva and blood of deer with chronic wasting disease. Science 2006; 314:133-6. 24. Lacroux C, Simon S, Benestad SL, Maillet S, Mathey J, Lugan S, et al. Prions in milk from ewes incubating natural scrapie. PLoS Pathog 2008; 4:1000238. 25. Seeger H, Heikenwalder M, Zeller N, Kranich J, Schwarz P, Gaspert A, et al. Coincident scrapie infection and nephritis lead to urinary prion excretion. Science 2005; 310:324-6. 26. Heikenwalder M, Kurrer MO, Margalith I, Kranich J, Zeller N, Haybaeck J, et al. Lymphotoxin-dependent prion replication in inflammatory stromal cells of granulomas. Immunity 2008; 29:998-1008. 27. Heikenwalder M, Zeller N, Seeger H, Prinz M, Klöhn PC, Schwarz P, et al. Chronic lymphocytic inflammation specifies the organ tropism of prions. Science 2005; 307:1107-10.


 28. Raabe OG, Yeh HC, Newton GJ, Phalen RF, Velasquez DJ. Deposition of inhaled monodisperse aerosols in small rodents. Inhaled Part 1975; 41:3-21. 29. Raabe OG, Al-Bayati MA, Teague SV, Rasolt A. Regional deposition of inhaled monodisperse coarse and fine aerosol particles in small laboratory animals. Ann Occup Hyg 1988; 32:53-63. 30. Haybaeck J, Heikenwalder M, Klevenz B, Schwarz P, Margalith I, Bridel C, et al. Aerosols transmit prions to immunocompetent and immunodeficient mice. PLoS Pathog 2011; 7:1001257. 31. Hainfellner JA, Jellinger K, Budka H. Testing for prion protein does not confirm previously reported conjugal CJD. Lancet 1996; 347:616-7. 32. Ligios C, Sigurdson CJ, Santucciu C, Carcassola G, Manco G, Basagni M, et al. PrP(Sc) in mammary glands of sheep affected by scrapie and mastitis. Nat Med 2005; 11:1137-8. 33. Denkers ND, Seelig DM, Telling GC, Hoover EA. Aerosol and nasal transmission of chronic wasting disease in cervidized mice. J Gen Virol 2010; 91:1651-8. 34. Nichols TA, Pulford B, Wyckoff AC, Meyerett C, Michel B, Gertig K, et al. Detection of protease-resistant cervid prion protein in water from a CWD-endemic area. Prion 2009; 3:171-83. 35. Llewelyn CA, Hewitt PE, Knight RS, Amar K, Cousens S, Mackenzie J, et al. Possible transmission of variant Creutzfeldt-Jakob disease by blood transfusion. Lancet 2004; 363:417-21.


 36. Peden AH, Head MW, Ritchie DL, Bell JE, Ironside JW. Preclinical vCJD after blood transfusion in a PRNP codon 129 heterozygous patient. Lancet 2004; 364:527-9. 37. Adjemian JZ, Howell J, Holzbauer S, Harris J, Recuenco S, McQuiston J, et al. A clustering of immune-mediated polyradiculoneuropathy among swine abattoir workers exposed to aerosolized porcine brains, Indiana, United States. Int J Occup Environ Health 2009; 15:331-8. 38. Agrawal A, Singh SK, Singh VP, Murphy E, Parikh I. Partitioning of asal and pulmonary resistance changes during noninvasive plethysmography in mice. J Appl Physiol 2008; 105:1975-9. 39. Bates JH, Irvin CG. Measuring lung function in mice: the phenotyping uncertainty principle. J Appl Physiol 2003; 94:1297-306. 40. Zanusso G, Ferrari S, Cardone F, Zampieri P, Gelati M, Fiorini M, et al. Detection of pathologic prion protein in the olfactory epithelium in sporadic Creutzfeldt-Jakob disease. N Engl J Med 2003; 348:711-9. 41. Tabaton M, Monaco S, Cordone MP, Colucci M, Giaccone G, Tagliavini F, et al. Prion deposition in olfactory biopsy of sporadic Creutzfeldt-Jakob disease. Ann Neurol 2004; 55:294-6.


 PRION www.landesbioscience.com


 Prion 5:3, 138-141; July/August/September 2011; © 2011 Landes Bioscience




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Accelerated shedding of prions following damage to the olfactory epithelium


Richard A. Bessen1,*, Jason M. Wilham2, Diana Lowe1, Christopher P. Watschke1, Harold Shearin1, Scott Martinka1, Byron Caughey2 and James A. Wiley1


+ Author Affiliations




1Department of Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, USA 2Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergies and Infectious Diseases, Hamilton, Montana, USA


ABSTRACT


In this study we investigated the role of damage to the nasal mucosa in the shedding of prions into nasal fluids as a pathway for prion transmission. Here we demonstrate that prions can replicate to high levels in the olfactory sensory epithelium (OSE) in hamsters and that induction of apoptosis in olfactory receptor neurons (ORNs) in the OSE resulted in sloughing off of the OSE from nasal turbinates into the lumen of the nasal airway. In the absence of nasotoxic treatment olfactory marker protein (OMP), which is specific for ORNs, was not detected in nasal lavages. However, after nasotoxic treatment that leads to apoptosis of ORNs both OMP and prion proteins were present in nasal lavages. The cellular debris that was released from the OSE into the lumen of the nasal airway was positive for both OMP and the disease-specific isoform of the prion protein, PrPSc. Using the real time quaking-induced conversion assay to quantify prions, a 100- to 1,000-fold increase in prion seeding activity was observed in nasal lavages following nasotoxic treatment. Since neurons replicate prions to higher levels than other cell types and ORNs are the most environmentally exposed neurons, we propose that an increase in ORN apoptosis or damage to the nasal mucosa in a host with a pre-existing prion infection of the OSE could lead to a substantial increase in the release of prion infectivity into nasal fluids. This mechanism of prion shedding from the olfactory mucosa could contribute to prion transmission.








Aerosols Transmit Prions to Immunocompetent and Immunodeficient Mice


 Johannes Haybaeck1.¤a, Mathias Heikenwalder1.¤b, Britta Klevenz2., Petra Schwarz1, Ilan Margalith1, Claire Bridel1, Kirsten Mertz1,3, Elizabeta Zirdum2, Benjamin Petsch2, Thomas J. Fuchs4, Lothar Stitz2*, Adriano Aguzzi1* 1 Department of Pathology, Institute of Neuropathology, University Hospital Zurich, Zurich, Switzerland, 2 Institute of Immunology, Friedrich-Loeffler-Institut, Tu¨ bingen, Germany, 3 Department of Pathology, Clinical Pathology, University Hospital Zurich, Zurich, Switzerland, 4 Department of Computer Science, Machine Learning Laboratory, ETH Zurich, Zurich, Switzerland


 Abstract


 Prions, the agents causing transmissible spongiform encephalopathies, colonize the brain of hosts after oral, parenteral, intralingual, or even transdermal uptake. However, prions are not generally considered to be airborne. Here we report that inbred and crossbred wild-type mice, as well as tga20 transgenic mice overexpressing PrPC, efficiently develop scrapie upon exposure to aerosolized prions. NSE-PrP transgenic mice, which express PrPC selectively in neurons, were also susceptible to airborne prions. Aerogenic infection occurred also in mice lacking B- and T-lymphocytes, NK-cells, follicular dendritic cells or complement components. Brains of diseased mice contained PrPSc and transmitted scrapie when inoculated into further mice. We conclude that aerogenic exposure to prions is very efficacious and can lead to direct invasion of neural pathways without an obligatory replicative phase in lymphoid organs. This previously unappreciated risk for airborne prion transmission may warrant re-thinking on prion biosafety guidelines in research and diagnostic laboratories.


 SNIP...


 In summary, our results establish aerosols as a surprisingly efficient modality of prion transmission. This novel pathway of prion transmission is not only conceptually relevant for the field of prion research, but also highlights a hitherto unappreciated risk factor for laboratory personnel and personnel of the meat processing industry. In the light of these findings, it may be appropriate to revise current prion-related biosafety guidelines and health standards in diagnostic and scientific laboratories being potentially confronted with prion infected materials. While we did not investigate whether production of prion aerosols in nature suffices to cause horizontal prion transmission, the finding of prions in biological fluids such as saliva, urine and blood suggests that it may be worth testing this possibility in future studies.


 Citation: Haybaeck J, Heikenwalder M, Klevenz B, Schwarz P, Margalith I, et al. (2011) Aerosols Transmit Prions to Immunocompetent and Immunodeficient Mice. PLoS Pathog 7(1): e1001257. doi:10.1371/journal.ppat.1001257 Editor: David Westaway, University of Alberta, Canada Received March 22, 2010; Accepted December 13, 2010; Published January 13, 2011




PLEASE SEE FULL TEXT, AND AGAIN, many thanks to PLOS for open access !!!




http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1001257





WHO Tables on Tissue Infectivity Distribution in Transmissible Spongiform Encephalopathies Updated 2010


 also in the references at bottom i saw ;


 12. A single positive marrow in multiple transmission attempts from cattle orally dosed with BSE-infected brain [Wells et al., 1999; Wells et al., 2005; Sohn et al., 2009].




http://www.who.int/bloodproducts/tablestissueinfectivity.pdf





snip... see full text ;




Thursday, December 22, 2011


 Risk of Prion Disease Transmission through Bovine-Derived Bone Substitutes: A Systematic Review Clin Implant Dent Relat Res. 2011 Dec 15. doi: 10.1111/j.1708-8208.2011.00407.x. [Epub ahead of print]




http://transmissiblespongiformencephalopathy.blogspot.com/2011/12/risk-of-prion-disease-transmission.html





Monday, January 17, 2011


 Aerosols Transmit Prions to Immunocompetent and Immunodeficient Mice




http://transmissiblespongiformencephalopathy.blogspot.com/2011/01/aerosols-transmit-prions-to.html





Monday, February 22, 2010


 Aerosol and Nasal Transmission of Chronic Wasting Disease in Cervidized Mice


 Published online ahead of print on 17 February 2010 as doi:10.1099/vir.0.017335-0 J Gen Virol (2010), DOI 10.1099/vir.0.017335-0 © 2010 Society for General Microbiology




http://chronic-wasting-disease.blogspot.com/2010/02/aerosol-and-nasal-transmission-of.html






 Friday, December 11, 2009






 CWD, FECES, ORAL LESIONS, Aerosol and intranasal transmission



 http://chronic-wasting-disease.blogspot.com/2009/12/cwd-feces-oral-lesions-aerosol-and.html








 2011 December Prion TSE update






 Monday, December 26, 2011




Prion Uptake in the Gut: Identification of the First Uptake and Replication Sites




http://transmissiblespongiformencephalopathy.blogspot.com/2011/12/prion-uptake-in-gut-identification-of.html






 Thursday, December 22, 2011


 Risk of Prion Disease Transmission through Bovine-Derived Bone Substitutes: A Systematic Review Clin Implant Dent Relat Res. 2011 Dec 15. doi: 10.1111/j.1708-8208.2011.00407.x. [Epub ahead of print]




http://transmissiblespongiformencephalopathy.blogspot.com/2011/12/risk-of-prion-disease-transmission.html






 Saturday, December 3, 2011


 Candidate Cell Substrates, Vaccine Production, and Transmissible Spongiform Encephalopathies


 Volume 17, Number 12—December 2011




http://transmissiblespongiformencephalopathy.blogspot.com/2011/12/candidate-cell-substrates-vaccine.html





Friday, December 23, 2011


 Oral Transmission of L-type Bovine Spongiform Encephalopathy in Primate Model


 Volume 18, Number 1—January 2012 Dispatch




http://transmissiblespongiformencephalopathy.blogspot.com/2011/12/oral-transmission-of-l-type-bovine.html





Tuesday, November 08, 2011


 Can Mortality Data Provide Reliable Indicators for Creutzfeldt-Jakob Disease Surveillance? A Study in France from 2000 to 2008 Vol. 37, No. 3-4, 2011


 Original Paper


 Conclusions:These findings raise doubt about the possibility of a reliable CJD surveillance only based on mortality data.




http://creutzfeldt-jakob-disease.blogspot.com/2011/11/can-mortality-data-provide-reliable.html




2006


 USA sporadic CJD cases rising ;


 There is a growing number of human CJD cases, and they were presented last week in San Francisco by Luigi Gambatti(?) from his CJD surveillance collection.


 He estimates that it may be up to 14 or 15 persons which display selectively SPRPSC and practically no detected RPRPSC proteins.




http://www.fda.gov/ohrms/dockets/ac/06/transcripts/1006-4240t1.htm




http://www.fda.gov/ohrms/dockets/ac/06/transcripts/2006-4240t1.pdf





2008 The statistical incidence of CJD cases in the United States has been revised to reflect that there is one case per 9000 in adults age 55 and older. Eighty-five percent of the cases are sporadic, meaning there is no known cause at present.




http://www.cjdfoundation.org/fact.html





CJD USA RISING, with UNKNOWN PHENOTYPE ;


 5 Includes 41 cases in which the diagnosis is pending, and 17 inconclusive cases;


 *** 6 Includes 46 cases with type determination pending in which the diagnosis of vCJD has been excluded.




http://www.cjdsurveillance.com/pdf/case-table.pdf






 Thursday, August 4, 2011





Terry Singeltary Sr. on the Creutzfeldt-Jakob Disease Public Health Crisis, Date aired: 27 Jun 2011 (SEE VIDEO)





http://transmissiblespongiformencephalopathy.blogspot.com/2011/08/terry-singeltary-sr-on-creutzfeldt.html






 Sunday, August 21, 2011


 The British disease, or a disease gone global, The TSE Prion Disease (SEE VIDEO)




http://transmissiblespongiformencephalopathy.blogspot.com/2011/08/british-disease-or-disease-gone-global.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





Thursday, December 8, 2011




S. Korea confirms second case of iatrogenic Creutzfeldt-Jakob disease 48-year-old man 2011/12/08 11:08 KST





http://usdavskorea.blogspot.com/2011/12/s-korea-confirms-second-case-of.html










 Thursday, December 08, 2011




A case of Iatrogenic Creutzfeldt Jakob Disease (iCJD) in a patient who had received a German-manufactured human dura mater graft 23 years ago





http://creutzfeldt-jakob-disease.blogspot.com/2011/12/case-of-iatrogenic-creutzfeldt-jakob.html





also, see incredible infection rate of TSE CWD on this game farm recently closed down. incredible. ...tss





Tuesday, December 20, 2011





CHRONIC WASTING DISEASE CWD WISCONSIN Almond Deer (Buckhorn Flats) Farm Update DECEMBER 2011





http://chronic-wasting-disease.blogspot.com/2011/12/chronic-wasting-disease-cwd-wisconsin.html






 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, June 15, 2011




Galveston, Texas - Isle port moves through thousands of heifers headed to Russia, none from Texas, Alabama, or Washington, due to BSE risk factor





http://transmissiblespongiformencephalopathy.blogspot.com/2011/06/galveston-texas-isle-port-moves-through.html








MAD COW DISEASE, TEXAS STYLE




http://www.organicconsumers.org/articles/article_23850.cfm









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








Saturday, November 19, 2011





Novel Prion Protein in BSE-affected Cattle, Switzerland





http://transmissiblespongiformencephalopathy.blogspot.com/2011/11/novel-prion-protein-in-bse-affected.html








Price of PRION TSE aka MAD COW POKER GOES UP $$$

 Saturday, December 3, 2011



Isolation of Prion with BSE Properties from Farmed Goat Volume 17, Number 12—December 2011

http://transmissiblespongiformencephalopathy.blogspot.com/2011/12/isolation-of-prion-with-bse-properties.html


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


2010-2011

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

Friday, December 23, 2011




Oral Transmission of L-type Bovine Spongiform Encephalopathy in Primate Model


 Volume 18, Number 1—January 2012 Dispatch






http://transmissiblespongiformencephalopathy.blogspot.com/2011/12/oral-transmission-of-l-type-bovine.html



 2011 Monday, September 26, 2011

L-BSE BASE prion and atypical sporadic CJD

http://bse-atypical.blogspot.com/2011/09/l-bse-base-prion-and-atypical-sporadic.html


SEE RISE OF SPORADIC CJD YEAR TO YEAR ;

http://www.cjd.ed.ac.uk/figures.htm

 TSS

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