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BMBL Section VII
Agent Summary Statements
Section VII-D: Prions


The Centers for Disease Control and Prevention and the National Institutes of Health wish to express our appreciation to Jiri Safar, M.D.; Darlene Groth, A.B.; Stephen J. DeArmond, M.D., Ph.D.; and Stanley B. Prusiner, M.D., of the University of California San Francisco, San Francisco, CA, for their contributions to this emerging field and the preparation of this section.

Prions are proteinaceous infectious particles that lack nucleic acids.(1) Prions are composed largely, if not entirely, of an abnormal isoform of a normal cellular protein. In mammals, prions are composed of an abnormal, pathogenic isoform of the prion protein (PrP), designated PrPSc. The "Sc" superscript was initially derived from the term scrapie because scrapie is the prototypic prion disease. Since all of the known prion diseases (Table 6) of mammals involve aberrant metabolism of PrP similar to that observed in scrapie, use of the "Sc" superscript is suggested for all abnormal, pathogenic PrP isoforms.(2) In this context, the "Sc" superscript is used to designate the scrapie-like isoform of PrP.

A chromosomal gene encodes PrP and no PrP genes are found in purified preparations of prions. PrPSc is derived from PrPC (the cellular isoform of PRP) by a posttranslational process whereby PrPSc acquires a high -sheet content.(3) Neither prion-specific nucleic acids nor virus-like particles have been detected in purified, infectious preparations. In fungi, evidence for three different prions has been accumulated.(4)

The mammalian prions cause scrapie and other related neurodegenerative diseases of humans and animals (Table 6). The prion diseases are also referred to as the transmissible spongiform encephalopathies (TSEs).(5)

Table 1. The Prion Diseases

Disease abbreviation) Natural Host Prion Pathogenic PrP Isoform
Scrapie sheep and goats scrapie prion OvPrPSc
Transmissible mink encephalopathy (TME) mink TME prion MkPrPSc
Chronic wasting disease (CWD) mule deer and elk CWD prion MdePrPSc
Bovine spongiform encephalopathy (BSE) cattle BSE prion BoPrPSc
Feline spongiform encephalopathy (FSE) cats FSE prion FePrPSc
Exotic ungulate encephalopathy (EUE) nyala and greater kudu EUE prion UngPrPSc
Kuru humans kuru prion HuPrPSc
Creutzfeldt-Jakob disease (CJD) humans CJD prion HuPrPSc
Gerstmann-Sträussler-Scheinker syndrome (GSS) humans GSS prion HuPrPSc
Gatal familial insomnia (FFI) humans FFI prion HuPrPSc



Species-specificity of prions. Unlike many viruses, the properties of prions change dramatically when they are passaged from one species to another. The results of transgenic (Tg) mouse studies indicate that when human prions are passaged into mice, their potential non-Tg pathogenicity for humans probably declines drastically.(6) The prions that are propagated in the non-Tg mice are now mouse prions, not human prions. The mouse prions contain mouse PrPSc, not human PrPSc. This species-specific change in the PrPSc molecule is accompanied by an alteration in the pathogenicity of the prion. In contrast to the human prions, mouse prions are highly pathogenic for mice. Our understanding of these species-specific changes in prion pathogenicity is derived largely from studies of mice expressing a variety of PrP transgenes. Because the PrPSc produced in the mouse is from mouse PrPC, it not possible to determine the origin of the prion initially inoculated into the mouse.(7)

It is noteworthy that the susceptibility of a particular species to prions from another species can be profoundly affected by different prion strains.(8) The properties manifested by prion strains such as incubation times and neuropathology profiles seem to be enciphered in the conformation of PrPSc.

Such considerations of the basic principles of prion biology help to form the basis for the biosafety classification of different prions.

Biosafety level classification. Human prions and those propagated in apes and monkeys are manipulated at Biosafety Level 2 or 3, depending on the studies being conducted. BSE prions are likewise manipulated at Biosafety Level 2 or 3, due to the possibility that BSE prions have been transmitted to humans in Great Britain and France.(9)

All other animal prions are considered Biosafety Level 2 pathogens. Thus, based on our current understanding of prion biology described above, once human prions are passaged in mice and mouse PrPSc is produced, these prions should be considered Biosafety Level 2 prions, even though the human prions are Biosafety Level 3 under most experimental conditions. An exception to this statement is in the case of mice expressing human or chimeric human/mouse transgenes. These transgenic mice produce human prions when infected with human prions and should be treated as Biosafety Level 2 or 3 in accord with the guidelines described above. The mechanism of prion spread among sheep and goats developing natural scrapie is unknown.(10)(11) CWD, TME, BSE, FSE, and EUE are all thought to occur after the consumption of prion-infected foods. (12)(13)(14)(15)

Human prion diseases. In the care of patients dying of human prion disease, the precautions used for patients with AIDS or hepatitis are certainly adequate. In contrast to these viral illnesses, the human prion diseases are not communicable or contagious.(16) There is no evidence of contact or aerosol transmission of prions from one human to another. However, they are infectious under some circumstances, such as ritualistic cannibalism in New Guinea causing kuru, the administration of prion-contaminated growth hormone causing iatrogenic CJD, and the transplantation of prion-contaminated dura mater grafts.(17)(18)(19) Familial CJD, GSS, and FFI are all dominantly inherited prion diseases; five different mutations of the PrP gene have been shown to be genetically linked to the development of inherited prion disease. Prions from many cases of inherited prion disease have been transmitted to apes, monkeys, and mice carrying human PrP transgenes.(20)(21)(22)

Surgical procedures. Surgical procedures on patients diagnosed with prion disease should be minimized. It is thought that CJD has been spread from a CJD patient to two other patients who underwent neurosurgical procedures in the same operating theater shortly thereafter.(23) Although there is no documentation of the transmission of prions to humans through droplets of blood or cerebrospinal fluid, or by exposure to intact skin, or gastric and mucous membranes, the risk of such occurrences is a possibility. Sterilization of the instruments and decontamination of the operating room should be performed in accordance with recommendations described below.

Because it is important to establish a 'definitive' diagnosis of a human prion disease and to distinguish between sporadic and familial cases and those acquired by infection as a result of medical procedures or from prion-contaminated food products, unfixed brain tissue should be obtained. For all cases of suspected human prion disease, a minimum of one cubic centimeter of unfixed cerebral cortex should be part of any biopsy. This specimen should be bisected from the cortical surface through to the underlying white matter with one half of the specimen formalin-fixed and the other half frozen.

Autopsies. Routine autopsies an-d the processing of small amounts of formalin-fixed tissues containing human prions require Biosafety Level 2 precautions.(24) At autopsy, the entire brain should be collected and cut into coronal sections about 1.5 inches (~4 cm) thick; small blocks of tissue can easily be removed from each coronal section and placed in fixative for subsequent histopathologic analyses. Each coronal section is immediately heat sealed in a heavy-duty plastic bag. The outside of this bag is assumed to be contaminated with prions and other pathogens. With fresh gloves or with the help of an assistant with uncontaminated gloves, the bag containing the specimen is placed into another plastic bag which does not have a contaminated outer surface. The samples should then be frozen on dry ice or placed directly in a -70C freezer for storage. At the very minimum, a coronal section of cerebral hemisphere containing the thalamus and one of the cerebellar hemisphere and brainstem should be taken and frozen.

The absence of any known effective treatment for prions disease demands caution. The highest concentrations of prions are in the central nervous system and its coverings. Based on animal studies, it is likely that high concentrations of prions are also found in spleen, thymus, lymph nodes, and lung. The main precaution to be taken when working with prion-infected or contaminated material is to avoid puncture of the skin.(25) The prosector should wear cut-resistant gloves if possible. If accidental contamination of skin occurs, the area is swabbed with 1N sodium hydroxide for 5 minutes and then washed with copious amounts of water. Tables 2-5 provide guidelines to reduce the chance of skin punctures, aerosols, and contamination of operating room, morgue surfaces and instruments. Unfixed samples of brain, spinal cord, and other tissues containing human prions should be processed with extreme care at Biosafety Level 3.

Bovine spongiform encephalopathy. The risk of infection for humans by BSE prions is unclear. Perhaps the most prudent approach is to study BSE prions in a Biosafety Level 2 or 3 facility depending on the samples to be studied, as noted above for human prions (i.e., brain, spinal cord).

Experimental rodent prion diseases. Mice and hamsters are the experimental animals of choice for all studies of prion disease. With the development of transgenic mice that are highly susceptible to human prions, the use of apes and monkeys is rarely needed. The highest titers of prions (~109.5 ID50/g) are found in the brain and spinal cord of laboratory rodents infected with adapted strains of prions;(26)(27) lower titers (~106 ID50/g) are present in the spleen and lymphoreticular system.(28)(29)

Physical properties of prions. The smallest infectious prion particle is probably a dimer of PrPSc; this estimate is consistent with an ionizing radiation target size of 55 ±9 kDa.(30) Therefore, prions may not be retained by most of the filters that efficiently eliminate bacteria and viruses. Additionally, prions aggregate into particles of non-uniform size and cannot be solubilized by detergents, except under denaturing conditions where infectivity is lost.(31)(32) Prions resist inactivation by nucleases,(33) UV-irradiation at 254 nm,(34)(35) and treatment with psoralens,(36) divalent cations, metal ion chelators, acids (between pH 3 and 7), hydroxylamine, formalin, boiling, or proteases.(37)(38)

Inactivation of prions. Prions are characterized by extreme resistance to conventional inactivation procedures including irradiation, boiling, dry heat, and chemicals (formalin, betapropiolactone, alcohols). While prion infectivity in purified samples is diminished by prolonged digestion with proteases,(39)(40)results from boiling in sodium dodecyl sulfate and urea are variable. Sterilization of rodent brain extracts with high titers of prions requires autoclaving at 132C for 4.5 hours (h). Denaturing organic solvents such as phenol or chaotropic reagents such as guanidine isothiocyanate or alkali such as NaOH can also be used for sterilization.(41)(42)(43)(44)(45) Prions are inactivated by 1N NaOH, 4.0 M guanidinium hydrochloride or isocyanate, sodium hypochlorite (2% free chlorine concentration), and steam autoclaving at 132C for 4.5 h.(46)(47)(48)(49) It is recommended that dry waste be autoclaved at 132C for 4.5 h or incinerated. Large volumes of infectious liquid waste containing high titers of prions can be completely sterilized by treatment with 1N NaOH (final concentration) or autoclaving at 132C for 4.5 h. Disposable plasticware, which can be discarded as a dry waste, is highly recommended. Because the paraformaldehyde vaporization procedure does not diminish prion titers, the biosafety cabinets must be decontaminated with 1N NaOH, followed by 1N HCl, and rinsed with water. HEPA filters should be autoclaved and incinerated.

Although there is no evidence to suggest that aerosol transmission occurs in the natural disease, it is prudent to avoid the generation of aerosols or droplets during the manipulation of tissues or fluids and during the necropsy of experimental animals. It is further strongly recommended that gloves be worn for activities that provide the opportunity for skin contact with infectious tissues and fluids. Formaldehyde-fixed and paraffin-embedded tissues, especially of the brain, remain infectious. Some investigators recommend that formalin-fixed tissues from suspected cases of prion disease be immersed for 30 min in 96% formic acid or phenol before histopathologic processing,(50) but such treatment may severely distort the microscopic neuropathology.

Handling and processing of tissues from patients with suspected prion disease. The special characteristics of work with prions require particular attention to the facilities, equipment, policies, and procedures involved. The related considerations outlined in the following tables should be incorporated into the laboratory's risk management for this work.

Table 2. Standard precautions* for autopsies of patients with suspected prion disease

*Not to be confused with "Standard Universal Precautions"

1. Attendance should be limited to at least one experienced pathologist and minimal staff. One of the staff avoids direct contact with the deceased but assists with handling of instruments and specimen containers.

2. Standard autopsy attire is mandatory.

a. A disposable, waterproof gown is worn in place of a cloth gown.

b. Cut-resistant gloves are worn underneath two pairs of surgical gloves or chain mail gloves are worn between two pairs of surgical gloves.

c. Aerosols are mainly created during opening of the skull with a Stryker saw. Appropriate respiratory protection should be worn (i.e., PAPR).

3. To reduce contamination of the autopsy suite:

a. The autopsy table is covered with an absorbent sheet that has a waterproof backing.

b. Contaminated instruments are placed on an absorbent pad.

c. The brain is removed while the head is in a plastic bag to reduce aerosolization and splatter.

d. The brain can be placed into a container with a plastic bag liner for weighing.

e. The brain is placed onto a cutting board and appropriate samples are dissected for snap freezing (see Table 4).

f. The brain or organs to be fixed are immediately placed into a container with 10% neutral buffered formalin.

g. In most cases of suspected prion disease, the autopsy can be limited to examination of the brain only. In cases requiring a full autopsy, consideration should be given to examining and sampling of thoracic and abdominal organs in situ.

Table 3. Autopsy suite decontamination procedures

1. Instruments (open box locks and jaws) and saw blades are placed into a large stainless steel dish, soaked for 1 h in 2N sodium hydroxide or 2 h in 1N sodium hydroxide, and then rinsed well in water before autoclaving at 134C (gravity displacement steam autoclaving for 1 h; porous load steam autoclaving for one 18-minute cycle at 30 lbs psi or six 3-minute cycles at 30 lbs psi).

2. The Stryker saw is cleaned by repeated wetting with 2N sodium hydroxide solution over a 1 h period. Appropriate washing to remove residual NaOH is required.

3. The absorbent table cover and instrument pads, disposable clothing, etc. are double bagged in appropriate infectious waste bags for incineration.

4. Any suspected areas of contamination of the autopsy table or room are decontaminated by repeated wetting over 1 h with 2N sodium hydroxide

Table 4. Brain cutting procedures

1. After adequate formaldehyde fixation (at least 10-14 days), the brain is examined and cut on a table covered with an absorbent pad with an impermeable backing.

2. Samples for histology are placed in cassettes labeled with "CJD precautions." For laboratories that do not have embedding and staining equipment or microtome dedicated to infectious diseases including CJD, blocks of formalin-fixed tissue can be placed in 96% absolute formic acid for 30 minutes, followed by fresh 10% neutral buffered formalin solution for at least 48 h.(51) The tissue block is then embedded in paraffin as usual. Standard neurohistological or immunohistochemical techniques are not obviously affected by formic acid treatment; however, in our experience, tissue sections are brittle and crack during sectioning.

3. All instruments and surfaces coming in contact with the tissue are decontaminated as described in Table 3.

4. Tissue remnants, cutting debris, and contaminated formaldehyde solution should be discarded within a plastic container as infectious hospital waste for eventual incineration.

Table 5. Tissue preparation

1. Histology technicians wear gloves, apron, laboratory coat, and face protection.

2. Adequate fixation of small tissue samples (e.g. biopsies) from a patient with suspected prion disease is followed by post-fixation in 96% absolute formic acid for 30 minutes, followed by 48 hours in fresh 10% formalin.

3. Liquid waste is collected in a 4L waste bottle containing 600 ml 6N sodium hydroxide.

4. Gloves, embedding molds, and all handling materials are disposed of as biohazardous waste.

5. Tissue cassettes are processed manually to prevent contamination of tissue processors.

6. Tissues are embedded in a disposable embedding mold. If used, forceps are decontaminated.

7. In preparing sections, gloves are worn, section waste is collected and disposed of in a biohazard waste receptacle. The knife stage is wiped with 1-2N NaOH, and the knife used is discarded immediately in a "biohazard sharps" receptacle. Slides are labeled with "CJD Precautions." The sectioned bloc is sealed with paraffin.

8. Routine staining:

a. Slides are processed by hand.

b. Reagents are prepared in 100 ml disposable specimen cups.

c. After placing the coverslip on, slides are decontaminated by soaking them for 1 h in 2N NaOH.

d. Slides are labeled as "Infectious-CJD."

9. Other suggestions:

a. Disposable specimen cups or slide mailers may be used for reagents.

b. Slides for immunocytochemistry may be processed in disposable petri dishes.

c. Equipment is decontaminated as described above.

References

1. Prusiner S.B. 1997. Prion diseases and the BSE crisis. Science 278:245-251.

2. Prusiner S.B., Baron H., Carlson G., Cohen F.E., DeArmond S.J., Gabizon R., Gambetti P., Hope J., Kitamoto T., Kretzschmar H.A., Laplanche J.-L., Tateishi J., Telling G., Weissmann C., Will R., In press. "Prions." In: Virus Taxonomy. 7th Report of the International Committee on Taxonomy of Viruses. Academic Press.

3. Pan K.-M., Baldwin M., Nguyen J., Gasset M., Serban A., Groth D., Mehlhorn I., Huang Z., Fletterick R.J., Cohen F.E., Prusiner S.B. 1993. Conversion of -helices into -sheets features in the formation of the scrapie prion proteins. Proc Natl Acad Sci USA 90:10962-10966.

4. Wickner R.B. 1997. A new prion controls fungal cell fusion incompatibility [Commentary]. Proc Natl Acad Sci USA 94:10012-10014.

5. Gajdusek, D.C. 1977. Unconventional viruses and the origin and disappearance of kuru. Science 197:943-960.

6. Telling G.C., Scott M., Mastrianni J., Gabizon R., Torchia M., Cohen F.E., DeArmond S.J., Prusiner S.B. 1995. Prion propagation in mice expressing human and chimeric PrP transgenes implicates the interaction of cellular PrP with another protein. Cell 83:79-90.

7. Prusiner S.B. 1997 (1)

8. Prusiner S.B. 1997 (1)

9. Will R.G., Ironside J.W., Zeidler M., Cousens S.N., Estibeiro K., Alperovitch A., Poser S., Pocchiari M., Hofman A., Smith P.G. 1996. A new variant of Creutzfeldt-Jakob disease in the UK. Lancet 347:921-925.

10. Foster J.D., McKelvey W.A.C., Mylne M.J.A., Williams A., Hunter N., Hope J., Fraser H. 1992. Studies on maternal transmission of scrapie in sheep by embryo transfer. Vet Rec 130:341-343.

11. Dickinson A.G., Stamp J.T., Renwick C.C. 1974. Maternal and lateral transmission of scrapie in sheep. J Comp Pathol 84:19-25.

12. Prusiner S.B. 1997 (1)

13. Gajdusek D.C. 1991. The transmissible amyloidoses: genetical control of spontaneous generation of infectious amyloid proteins by nucleation of configurational change in host precursors: kuru-CJD-GSS-scrapie-BSE. Eur J Epidemiol 7:567-577.

14. Marsh R.F., 1992. "Transmissible mink encephalopathy." In: Prion Diseases of Humans and Animals. Prusiner S.B., Collinge J., Powell J., Anderton B., Eds. Ellis Horwood, London, pp. 300-307.

15. Collinge J., Palmer M.S., 1997. "Human prion diseases." In: Prion Diseases. Collinge J., Palmer M.S., Eds. Oxford University Press, Oxford, U.K., pp. 18-56.

16. Ridley R.M., Baker H.F. 1993. Occupational risk of Creutzfeldt-Jakob disease. Lancet 341:641-642.

17. Gajdusek D.C. 1977 (5)

18. Public Health Service Interagency Coordinating Committee. 1997. Report on Human Growth Hormone and Creutzfeldt-Jakob Disease. 14:1-11.

19. CDC. 1997. Creutzfeldt-Jakob disease associated with cadaveric dura mater grafts - Japan, January 1979-May 1996. MMWR 46:1066-1069.

20. Telling G.C., et al. 1995. (6)

21. Brown P., Gibbs C.J., Jr., Rodgers-Johnson P., Asher D.M., Sulima M.P., Bacote A., Goldfarb L.G., Gajdusek D.C. 1994. Human spongiform encephalopathy: the National Institutes of Health series of 300 cases of experimentally transmitted disease. Ann Neurol 35:513-529.

22. Telling G.C., Parchi P., DeArmond S.J., Cortelli P., Montagna P., Gabizon R., Mastrianni J., Lugaresi E., Gambetti P., Prusiner S.B. 1996. Evidence for the conformation of the pathologic isoform of the prion protein enciphering and propagating prion diversity. Science 274:2079-2082.

23. Brown P., Preece M.A., Will R.G. 1992. "Friendly fire" in medicine: hormones, homografts, and Creutzfeldt-Jakob disease. Lancet 340:24-27.

24. Ironside J.W., Bell J.E. 1996. The 'high-risk' neuropathological autopsy in AIDS and Creutzfeldt-Jakob disease: principles and practice. Neuropathol Appl Neurobiol 22:388-393.

25. Ridley R.M., Baker H.F. 1993. (16)

26. Eklund C.M., Kennedy R.C., Hadlow W.J. 1967. Pathogenesis of scrapie virus infection in the mouse. J Infect Dis 117:15-22.

27. Prusiner S.B., Groth D.F., Cochran S.P., Masiarz F.R., McKinley M.P., Martinez H.M. 1980. Molecular properties, partial purification, and assay by incubation period measurements of the hamster scrapie agent. Biochemistry 19:4883-4891.

28. Prusiner S.B., Hadlow W.J., Eklund C.M., Race R.E., Cochran S.P. 1978. Sedimentation characteristics of the scrapie agent from murine spleen and brain. Biochemistry 17:4987-4992.

29. Kimberlin R.H. 1976. Scrapie in the Mouse . Meadowfield Press, Durham, England.

30. Bellinger-Kawahara C.G., Kempner E., Groth D.F., Gabizon R., Prusiner S.B. 1988. Scrapie prion liposomes and rods exhibit target sizes of 55,000 Da. Virology 164:537-541.

31. - Gabizon R., Prusiner S.B. 1990. Prion liposomes. Biochem J 266:1-14.

32. Safar J., Ceroni M., Piccardo P., Liberski P.P., Miyazaki M., Gajdusek D.C., Gibbs C.J., Jr. 1990. Subcellular distribution and physicochemical properties of scrapie associated precursor protein and relationship with scrapie agent. Neurology 40:503-508.

33. Bellinger-Kawahara C., Diener T.O., McKinley M.P., Groth D.F., Smith D.R., Prusiner S.B. 1987. Purified scrapie prions resist inactivation by procedures that hydrolyze, modify, or shear nucleic acids. Virology 160:271-274.

34. Alper T., Cramp W.A., Haig D.A., Clarke M.C. 1967. Does the agent of scrapie replicate without nucleic acid? Nature 214:764-766.

35. Bellinger-Kawahara C., Cleaver J.E., Diener T.O., Prusiner S.B. 1987. Purified scrapie prions resist inactivation by UV irradiation. J Virol 61:159-166.

36. McKinley M.P., Masiarz F.R., Isaacs S.T., Hearst J.E., Prusiner S.B. 1983. Resistance of the scrapie agent to inactivation by psoralens. Photochem Photobiol 37:539-545.

37. Prusiner S.B. 1982. Novel proteinaceous infectious particles cause scrapie. Science 216:136-144.

38. Brown P., Wolff A., Gajdusek D.C. 1990. A simple and effective method for inactivating virus infectivity in formalin-fixed samples from patients with Creutzfeldt-Jakob disease. Neurology 40:887-890.

39. Prusiner S.B., McKinley M.P., Groth D.F., Bowman K.A., Mock N.I., Cochran S.P., Masiarz F.R. 1981. Scrapie agent contains a hydrophobic protein. Proc Natl Acad Sci USA 78:6675-6679.

40. McKinley M.P., Bolton D.C., Prusiner S.B. 1983. A protease-resistant protein is a structural component of the scrapie prion. Cell 35:57-62.

41. Prusiner S.B., Groth D.F., McKinley M.P., Cochran S.P., Bowman K.A., Kasper K.C. 1981. Thiocyanate and hydroxyl ions inactivate the scrapie agent. Proc Natl Acad Sci USA 78:4606-4610.

42. Prusiner S.B., McKinley M.P., Bolton D.C., Bowman K.A., Groth D.F., Cochran S.P., Hennessey E.M., Braunfeld M.B., Baringer J.R., Chatigny M.A., 1984. "Prions: methods for assay, purification and characterization." In: Methods in Virology. Maramorosch K., Koprowski H., Eds. Academic Press, New York, pp. 293-345.

43. Prusiner S.B., Groth D., Serban A., Stahl N., Gabizon R. 1993. Attempts to restore scrapie prion infectivity after exposure to protein denaturants. Proc Natl Acad Sci USA 90:2793-2797.

44. Taylor D.M., Woodgate S.L., Atkinson M.J. 1995. Inactivation of the bovine spongiform encephalopathy agent by rendering procedures. Vet Rec 137:605-610.

45. Taylor D.M., Woodgate S.L., Fleetwood A.J., Cawthorne R.J.G. 1997. Effect of rendering procedures on the scrapie agent. Vet Rec 141:643-649.

46. Prusiner, S.B., et al. 1984. (42)

47. Prusiner, S.B. et al. 1993. (43)

48. Taylor D.M., Woodgate S.L., Atkinson M.J. 1995. (44)

49. Taylor, D.M. et al. 1997. (45)

50. Brown P., Wolff A., Gajdusek D.C. 1990. (38)

51. Brown P., Wolff A., Gajdusek D.C. 1990. (38)



This page last reviewed June 17, 1999





http://www.cdc.gov/od/ohs/biosfty/bmbl4/bmbl4s7d.htm


I updated them in 2004 and they actually printed all 14 pages. they even commented with 'commented noted', amazing. i think mine was the only one of support of the lab. here is the actual letter. it is printed in the February 2005 Final Environmental Impact Statement for the Galveston National Laboratory for Biodefense and Emerging Infectious Diseases Research Facility in Galveston, Texas.



-------- Original Message --------
Subject: PUBLIC COMMENT ON DEIS GALVESTON NATIONAL LAB. FOR BIODEFENSE AND EMERGING INFECTIOUS DISEASE RESEARCH FACILITY
Date: Tue, 14 Dec 2004 09:50:02 -0600
From: "Terry S. Singeltary Sr."
To: [email protected]
CC: [email protected], [email protected], [email protected], [email protected], [email protected]


Hello Valerie and UTMB,

My name is Terry S. Singeltary Sr., I live in Bacliff, Texas, Galveston Co.,
and I kindly wish to comment on the DEIS as follows ;

TODAY, December 14, 2004 marks the 7 year anniversary of the
death of my mother right here in Galveston Co. to a most hideous
emerging infectious diseases, the Heidenhain Variant Creutzfeldt Jakob
disease aka mad cow disease (Human Transmissible Spongiform
Encephalopathy), one of many documented phenotypes of this agent.
TO top that off, exactly one year previously to the day 12/14/96, my
neighbor lost his mother to Creutzfeldt Jakob disease, both cases
confirmed. FOR this reason, I support fully the building of this facility
in Galveston county. I recieved the full copy of the DEIS and on page
B-4 under PRIONS, you outline such a threat from this agent. Nothing
emerging about TSEs, they have been spreading in the USA for decades.

IN Nov. 2001, I had my 3rd neck surgery to fuse and plate my cervical
spine from a old neck injury. My neurosurgeon had to use some special
tools and a bone grinder that would not be used on anyone else, due to
the risk factor I now have from what my Mother died from (hvCJD) and
it's long incubation period of up to 40 years. ALSO, I refused cadaver
bone and blood for fear of additional exposure to the CJD/TSE agent,
and used my own. Low and behold, they infect me with another super
bug called MRSA. Damn near died, 7 weeks vancomycin straight to
the heart via long PIC-line. NOW, 2004 Galveston Co. Texas has it's
own MRSA epidemic going on in the community. NOW in our bays
we have a new flesh eating bug (saltwater bacteria vibrio vulnificus)
that to be frank, scares the hell out of me since my ordeal with the MRSA.

MY point is that we are surrounded by dangerous and deadly pathogens
and they are growing in numbers, from the threat of Terrorism to Global
warming, these pathogens are not going anywhere. WITH Texas City
Chemical plants on the south side of me and Bayport to the North and
all the pollutants they spew out on a daily basis for all to breath, a
facility
to study the Biodefense of the USA and Emerging Infectious Disease
at UTMB will be nothing more than a breath of fresh air to me...

THANK YOU!...


EFSA Scientific Report on the Assessment of the Geographical BSE-Risk
(GBR) of the United States of America (USA)
Publication date: 20 August 2004

Adopted July 2004 (Question N° EFSA-Q-2003-083)

* 167 kB Report


* 105 kB Summary


Summary of the Scientific Report

The European Food Safety Authority and its Scientific Expert Working
Group on the Assessment of the Geographical Bovine Spongiform
Encephalopathy (BSE) Risk (GBR) were asked by the European Commission
(EC) to provide an up-to-date scientific report on the GBR in the United
States of America, i.e. the likelihood of the presence of one or more
cattle being infected with BSE, pre-clinically as well as clinically, in
USA. This scientific report addresses the GBR of USA as assessed in 2004
based on data covering the period 1980-2003.

The BSE agent was probably imported into USA and could have reached
domestic cattle in the middle of the eighties. These cattle imported in
the mid eighties could have been rendered in the late eighties and
therefore led to an internal challenge in the early nineties. It is
possible that imported meat and bone meal (MBM) into the USA reached
domestic cattle and leads to an internal challenge in the early nineties.

A processing risk developed in the late 80s/early 90s when cattle
imports from BSE risk countries were slaughtered or died and were
processed (partly) into feed, together with some imports of MBM. This
risk continued to exist, and grew significantly in the mid 90's when
domestic cattle, infected by imported MBM, reached processing. Given the
low stability of the system, the risk increased over the years with
continued imports of cattle and MBM from BSE risk countries.

EFSA concludes that the current GBR level of USA is III, i.e. it is
likely but not confirmed that domestic cattle are (clinically or
pre-clinically) infected with the BSE-agent. As long as there are no
significant changes in rendering or feeding, the stability remains
extremely/very unstable. Thus, the probability of cattle to be
(pre-clinically or clinically) infected with the BSE-agent persistently
increases.

http://www.efsa.eu.int/science/efsa_scientific_reports/gbr_assessments/573_en.html

ONE YEAR PREVIOUSLY, MY SUBMISSION TO THE FDA ;

From: Terry S. Singeltary Sr. [[email protected]]
Sent: Tuesday, July 29, 2003 1:03 PM
To: [email protected]
Cc: [email protected]; [email protected]; BSE-L
Subject: Docket No. 2003N-0312 Animal Feed Safety System [TSS SUBMISSION
TO DOCKET 2003N-0312]

Greetings FDA,

snip...

PLUS, if the USA continues to flagrantly ignore the _documented_ science
to date about the known TSEs in the USA (let alone the undocumented TSEs
in cattle), it is my opinion, every other Country that is dealing with
BSE/TSE should boycott the USA and demand that the SSC reclassify the
USA BSE GBR II risk assessment to BSE/TSE GBR III 'IMMEDIATELY'. for the
SSC to _flounder_ any longer on this issue, should also be regarded with
great suspicion as well. NOT to leave out the OIE and it's terribly
flawed system of disease surveillance. the OIE should make a move on CWD
in the USA, and make a risk assessment on this as a threat to human
health. the OIE should also change the mathematical formula for testing
of disease. this (in my opinion and others) is terribly flawed as well.
to think that a sample survey of 400 or so cattle in a population of 100
million, to think this will find anything, especially after seeing how
many TSE tests it took Italy and other Countries to find 1 case of BSE
(1 million rapid TSE test in less than 2 years, to find 102 BSE cases),
should be proof enough to make drastic changes of this system. the OIE
criteria for BSE Country classification and it's interpretation is very
problematic. a text that is suppose to give guidelines, but is not
understandable, cannot be considered satisfactory. the OIE told me 2
years ago that they were concerned with CWD, but said any changes might
take years. well, two years have come and gone, and no change in
relations with CWD as a human health risk. if we wait for politics and
science to finally make this connection, we very well may die before any
decisions
or changes are made. this is not acceptable. we must take the politics
and the industry out of any final decisions of the Scientific community.
this has been the problem from day one with this environmental man made
death sentence. some of you may think i am exaggerating, but you only
have to see it once, you only have to watch a loved one die from this
one time, and you will never forget, OR forgive...yes, i am still very
angry... but the transmission studies DO NOT lie, only the politicians
and the industry do... and they are still lying to this day...TSS


http://www.fda.gov/ohrms/dockets/dockets/03n0312/03N-0312_emc-000001.txt


Docket No, 04-047-l Regulatory Identification No. (RIN) 091O-AF46 NEW
BSE SAFEGUARDS (comment submission)

https://web01.aphis.usda.gov/regpublic.nsf/0/eff9eff1f7c5cf2b87256ecf000df08d?OpenDocument

Docket No. 03-080-1 -- USDA ISSUES PROPOSED RULE TO ALLOW LIVE ANIMAL
IMPORTS FROM CANADA


https://web01.aphis.usda.gov/BSEcom.nsf/0/b78ba677e2b0c12185256dd300649f9d?OpenDocument&AutoFramed


Docket No. 2003N-0312 Animal Feed Safety System [TSS SUBMISSION]

http://www.fda.gov/ohrms/dockets/dockets/03n0312/03N-0312_emc-000001.txt

Docket Management Docket: 02N-0273 - Substances Prohibited From Use in

Animal Food or Feed; Animal Proteins Prohibited in Ruminant Feed

Comment Number: EC -10

Accepted - Volume 2


http://www.fda.gov/ohrms/dockets/dailys/03/Jan03/012403/8004be07.html


PART 2


http://www.fda.gov/ohrms/dockets/dailys/03/Jan03/012403/8004be09.html


PDF]Freas, William TSS SUBMISSION

File Format: PDF/Adobe Acrobat -

Page 1. J Freas, William From: Sent: To: Subject: Terry S. Singeltary

Sr. [[email protected]] Monday, January 08,200l 3:03 PM freas ...


http://www.fda.gov/ohrms/dockets/ac/01/slides/3681s2_09.pdf


Asante/Collinge et al, 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;


http://www.fda.gov/ohrms/dockets/ac/03/slides/3923s1_OPH.htm


Docket Management Docket: 96N-0417 - Current Good Manufacturing Practice
in Manufacturing, Packing, or Holding Dietary Ingredients a
Comment Number: EC -2
Accepted - Volume 7

http://www.fda.gov/ohrms/dockets/dailys/03/Mar03/031403/96N-0417-EC-2.htm


[PDF] Appendices to PL107-9 Inter-agency Working Group Final Report 1-1
File Format: PDF/Adobe Acrobat - View as HTML
Agent, Weapons of Mass Destruction Operations Unit Federal Bureau of
those who provided comments in response to Docket No. ...
Meager 8/18/01 Terry S. Singeltary Sr ...


www.aphis.usda.gov/lpa/pubs/pubs/PL107-9_Appen.pdf

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

http://www.fda.gov/ohrms/dockets/dockets/03n0312/03N-0312_emc-000001.txt

# Docket No: 02-088-1 RE-Agricultural Bioterrorism Protection Act of
2002; [TSS SUBMISSION ON POTENTIAL FOR BSE/TSE & FMD 'SUITCASE BOMBS'] -
TSS 1/27/03 (0)

Docket Management

Docket: 02N-0276 - Bioterrorism Preparedness; Registration of Food Facilities, Section 305
Comment Number: EC-254 [TSS SUBMISSION]

http://www.fda.gov/ohrms/dockets/dockets/02n0276/02N-0276-EC-254.htm


Dockets Entered On October 2, 2003 Table of Contents, Docket #,
Title, 1978N-0301,

OTC External Analgesic Drug Products, ... EMC 7, Terry S. Singeltary Sr.
Vol #: 1, ...

http://www.fda.gov/ohrms/dockets/dailys/03/oct03/100203/100203.htm


Daily Dockets Entered on 02/05/03

DOCKETS ENTERED on 2/5/03. ... EMC 4 Terry S. Singeltary Sr. Vol#: 2.
... Vol#: 1.

03N-0009 Federal Preemption of State & Local Medical Device Requireme. ...


http://www.fda.gov/ohrms/dockets/dailys/03/Feb03/020503/020503.htm


Docket Management

Docket: 02N-0370 - Neurological Devices; Classification of Human Dura Mater

Comment Number: EC -1

Accepted - Volume 1


http://www.fda.gov/ohrms/dockets/dailys/03/Jan03/012403/8004be11.html


http://www.fda.gov/ohrms/dockets/dailys/03/Jan03/012403/8004bdfe.html


http://www.fda.gov/ohrms/dockets/dailys/03/Jan03/012403/8004bdfc.html


Daily Dockets - 04/10/03

... 00D-1662 Use of Xenotransplantation Products in Humans.
EMC 98 Terry S. Singeltary Sr. Vol#: 3. 01F ...
http://www.fda.gov/ohrms/dockets/dailys/03/Apr03/041003/041003.htm - 05-20-2003
- Cached


2003D-0186
Guidance for Industry: Use of Material From Deer and Elk In Animal Feed



EMC 1
Terry S. Singeltary Sr.
Vol #:
1

http://www.fda.gov/ohrms/dockets/dailys/03/Jun03/060903/060903.htm


2003D-0186
Guidance for Industry: Use of Material From Deer and Elk In Animal Feed


EMC 7
Terry S. Singeltary Sr.
Vol #:
1

2003D-0186
Guidance for Industry: Use of Material From Deer and Elk In Animal Feed


EMC 7
Terry S. Singeltary Sr.
Vol #:
1


http://www.fda.gov/ohrms/dockets/dailys/03/oct03/100203/100203.htm

01N-0423 Substances Prohibited from use in animal food/Feed Ruminant

APE 5 National Renderers Association, Inc. Vol#: 2

APE 6 Animal Protein Producers Industry Vol#: 2

APE 7 Darling International Inc. Vol#: 2

EMC 1 Terry S. Singeltary Sr. Vol#: 3

http://www.fda.gov/ohrms/dockets/dailys/01/Oct01/101501/101501.htm

Send Post-Publication Peer Review to journal:


Re: RE-Monitoring the occurrence of emerging forms of Creutzfeldt-Jakob

disease in the United States


Email Terry S. Singeltary:


[email protected]


I lost my mother to hvCJD (Heidenhain Variant CJD). I would like to

comment on the CDC's attempts to monitor the occurrence of emerging

forms of CJD. Asante, Collinge et al [1] have reported 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. However, CJD and all human TSEs are not reportable

nationally. CJD and all human TSEs must be made reportable in every

state and internationally. I hope that the CDC does not continue to

expect us to still believe that the 85%+ of all CJD cases which are

sporadic are all spontaneous, without route/source. We have many TSEs in

the USA in both animal and man. CWD in deer/elk is spreading rapidly and

CWD does transmit to mink, ferret, cattle, and squirrel monkey by

intracerebral inoculation. With the known incubation periods in other

TSEs, oral transmission studies of CWD may take much longer. Every

victim/family of CJD/TSEs should be asked about route and source of this

agent. To prolong this will only spread the agent and needlessly expose

others. In light of the findings of Asante and Collinge et al, there

should be drastic measures to safeguard the medical and surgical arena

from sporadic CJDs and all human TSEs. I only ponder how many sporadic

CJDs in the USA are type 2 PrPSc?


http://www.neurology.org/cgi/eletters/60/2/176#535


LANCET INFECTIOUS DISEASE JOURNAL


Volume 3, Number 8 01 August 2003


Newsdesk


Tracking spongiform encephalopathies in North America


Xavier Bosch

My name is Terry S Singeltary Sr, and I live in Bacliff, Texas. I lost

my mom to hvCJD (Heidenhain variant CJD) and have been searching for

answers ever since. What I have found is that we have not been told the

truth. CWD in deer and elk is a small portion of a much bigger problem.


49-year-old Singeltary is one of a number of people who have remained

largely unsatisfied after being told that a close relative died from a

rapidly progressive dementia compatible with spontaneous

Creutzfeldt-Jakob disease (CJD). So he decided to gather hundreds of

documents on transmissible spongiform encephalopathies (TSE) and

realised that if Britons could get variant CJD from bovine spongiform

encephalopathy (BSE), Americans might get a similar disorder from

chronic wasting disease (CWD)the relative of mad cow disease seen among

deer and elk in the USA. Although his feverish search did not lead him

to the smoking gun linking CWD to a similar disease in North American

people, it did uncover a largely disappointing situation.


Singeltary was greatly demoralised at the few attempts to monitor the

occurrence of CJD and CWD in the USA. Only a few states have made CJD

reportable. Human and animal TSEs should be reportable nationwide and

internationally, he complained in a letter to the Journal of the

American Medical Association (JAMA 2003; 285: 733). I hope that the CDC

does not continue to expect us to still believe that the 85% plus of all

CJD cases which are sporadic are all spontaneous, without route or source.


Until recently, CWD was thought to be confined to the wild in a small

region in Colorado. But since early 2002, it has been reported in other

areas, including Wisconsin, South Dakota, and the Canadian province of

Saskatchewan. Indeed, the occurrence of CWD in states that were not

endemic previously increased concern about a widespread outbreak and

possible transmission to people and cattle.


To date, experimental studies have proven that the CWD agent can be

transmitted to cattle by intracerebral inoculation and that it can cross

the mucous membranes of the digestive tract to initiate infection in

lymphoid tissue before invasion of the central nervous system. Yet the

plausibility of CWD spreading to people has remained elusive.


Part of the problem seems to stem from the US surveillance system. CJD

is only reported in those areas known to be endemic foci of CWD.

Moreover, US authorities have been criticised for not having performed

enough prionic tests in farm deer and elk.


Although in November last year the US Food and Drug Administration

issued a directive to state public-health and agriculture officials

prohibiting material from CWD-positive animals from being used as an

ingredient in feed for any animal species, epidemiological control and

research in the USA has been quite different from the situation in the

UK and Europe regarding BSE.


Getting data on TSEs in the USA from the government is like pulling

teeth, Singeltary argues. You get it when they want you to have it,

and only what they want you to have.


Norman Foster, director of the Cognitive Disorders Clinic at the

University of Michigan (Ann Arbor, MI, USA), says that current

surveillance of prion disease in people in the USA is inadequate to

detect whether CWD is occurring in human beings; adding that, the

cases that we know about are reassuring, because they do not suggest the

appearance of a new variant of CJD in the USA or atypical features in

patients that might be exposed to CWD. However, until we establish a

system that identifies and analyses a high proportion of suspected prion

disease cases we will not know for sure. The USA should develop a

system modelled on that established in the UK, he points out.


Ali Samii, a neurologist at Seattle VA Medical Center who recently

reported the cases of three hunterstwo of whom were friendswho died

from pathologically confirmed CJD, says that at present there are

insufficient data to claim transmission of CWD into humans; adding that

[only] by asking [the questions of venison consumption and deer/elk

hunting] in every case can we collect suspect cases and look into the

plausibility of transmission further. Samii argues that by making both

doctors and hunters more aware of the possibility of prions spreading

through eating venison, doctors treating hunters with dementia can

consider a possible prion disease, and doctors treating CJD patients

will know to ask whether they ate venison.


CDC spokesman Ermias Belay says that the CDC will not be investigating

the [Samii] cases because there is no evidence that the men ate

CWD-infected meat. He notes that although the likelihood of CWD

jumping the species barrier to infect humans cannot be ruled out 100%

and that [we] cannot be 100% sure that CWD does not exist in humans&

the data seeking evidence of CWD transmission to humans have been very

limited.



http://infection.thelancet.com/journal/journal.isa



he complained in a letter to the Journal of the American Medical


Association (JAMA 2003; 285: 733). I hope that the CDC does not

continue to expect us to still believe that the 85% plus of all CJD

cases which are sporadic are all spontaneous, without route or source.<<<


actually, that quote was from a more recent article in the Journal of

Neurology (see below), not the JAMA article...


Full Text

Diagnosis and Reporting of Creutzfeldt-Jakob Disease

Singeltary, Sr et al. JAMA.2001; 285: 733-734.


http://jama.ama-assn.org/cgi/content/full/285/6/733?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=dignosing+and+reporting+creutzfeldt+jakob+disease&searchid=1048865596978_1528&stored_search=&FIRSTINDEX=0&journalcode=jama


BRITISH MEDICAL JOURNAL


SOMETHING TO CHEW ON


BMJ


http://www.bmj.com/cgi/eletters/319/7220/1312/b#EL2


BMJ


http://www.bmj.com/cgi/eletters/320/7226/8/b#EL1


THE PATHOLOGICAL PROTEIN

BY Philip Yam

Yam Philip Yam News Editor Scientific American www.sciam.com
http://www.thepathologicalprotein.com/

IN light of Asante/Collinge et al 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;

-------- Original Message -------- Subject: re-BSE prions propagate as

either variant CJD-like or sporadic CJD Date: Thu, 28 Nov 2002 10:23:43

-0000 From: "Asante, Emmanuel A" To:
"'[email protected]'"

Dear Terry,

I have been asked by Professor Collinge to respond to your request. I am

a Senior Scientist in the MRC Prion Unit and the lead author on the

paper. I have attached a pdf copy of the paper for your attention. Thank

you for your interest in the paper.

In respect of your first question, the simple answer is, yes. As you

will find in the paper, we have managed to associate the alternate

phenotype to type 2 PrPSc, the commonest sporadic CJD.

It is too early to be able to claim any further sub-classification in

respect of Heidenhain variant CJD or Vicky Rimmer's version. It will

take further studies, which are on-going, to establish if there are

sub-types to our initial finding which we are now reporting. The main

point of the paper is that, as well as leading to the expected new

variant CJD phenotype, BSE transmission to the 129-methionine genotype

can lead to an alternate phenotype which is indistinguishable from type

2 PrPSc.


I hope reading the paper will enlighten you more on the subject. If I

can be of any further assistance please to not hesitate to ask. Best wishes.


Emmanuel Asante

<> ____________________________________

Dr. Emmanuel A Asante MRC Prion Unit & Neurogenetics Dept. Imperial

College School of Medicine (St. Mary's) Norfolk Place, LONDON W2 1PG

Tel: +44 (0)20 7594 3794 Fax: +44 (0)20 7706 3272 email:

[email protected] (until 9/12/02)

New e-mail: [email protected] (active from now)

____________________________________

snip...

full text ;

http://www.fda.gov/ohrms/dockets/ac/03/slides/3923s1_OPH.htm


AND the new findings of BASE in cattle in Italy of Identification of a
second bovine amyloidotic spongiform encephalopathy: Molecular
similarities with sporadic

Creutzfeldt-Jakob disease


http://www.pnas.org/cgi/content/abstract/0305777101v1


Adaptation of the bovine spongiform encephalopathy agent to primates
and comparison with Creutzfeldt- Jakob disease: Implications for
human health

THE findings from Corinne Ida Lasmézas*, [dagger] , Jean-Guy Fournier*,
Virginie Nouvel*,

Hermann Boe*, Domíníque Marcé*, François Lamoury*, Nicolas Kopp [Dagger

] , Jean-Jacques Hauw§, James Ironside¶, Moira Bruce [||] , Dominique

Dormont*, and Jean-Philippe Deslys* et al, that The agent responsible
for French iatrogenic growth hormone-linked CJD taken as a control is
very different from vCJD but is similar to that found in one case of
sporadic CJD and one sheep scrapie isolate;

http://www.pnas.org/cgi/content/full/041490898v1

Characterization of two distinct prion strains
derived from bovine spongiform encephalopathy
transmissions to inbred mice

http://vir.sgmjournals.org/cgi/content/abstract/85/8/2471


11 November 2004 Text only version of this site
Print
this page




Genetic make-up may determine what type of CJD occurs when humans are
infected with BSE

New research published by a team from the Medical Research Council (MRC)
Prion Unit offers an explanation about why only people with a particular
genetic make-up have so far developed vCJD. It also provides evidence
that other types of BSE-derived prion infection with a different pattern
of symptoms might occur in humans. The findings are published in the
journal Science.

Variant CJD (vCJD) is the human disease thought to be caused by eating
food contaminated with the infectious agent, known as a prion,
responsible for the epidemic of BSE or "mad cow disease" in cattle. So
far, everyone known to have developed vCJD has been of a particular
genetic type - known as MM. Until now it has been a mystery why everyone
that has developed vCJD is of the MM type and one possibility is that
they are simply the first to develop the disease when infected with BSE,
and that people with the other genetic types1 (known as VV and MV*)
infected with BSE prions will also develop vCJD, but some years later.

In a series of experiments spanning more than ten years, the MRC team
has been studying mice genetically modified so that they make human
prion proteins - which are used to model human susceptibility to BSE.
The team has now shown that mice with the human VV genetic type do
become infected when given BSE or vCJD prions, but manifest a different
form of the disease which looks quite different to vCJD and has a novel
prion "strain" type.

Remarkably, when these novel prions were used to infect mice of the MM
genetic type, the mice either developed a disease very like vCJD, or
else a pattern of disease that looks like so-called sporadic CJD - the
"classical" form of CJD. This form has been known about for many years,
is seen all over the world and has not hitherto been associated with
BSE. However, the new strain identified in the mice, being called 'type
5', has not been seen yet in people and we do not know what pattern of
disease it would cause. It could look like one of the forms of classical
or sporadic CJD or perhaps be yet another different "variant" form.

The work from the MRC team suggests that type 4 prions, the type
associated with vCJD, can only propagate themselves in people that make
the M form of the protein. It seems the V form of the protein just
cannot adopt the particular molecular shape that characterises type 4.

The studies in mice also suggest that if these prions were to pass from
person to person (for example by blood transfusion) then, depending on
the genetic type of the person becoming infected, at least three
different patterns of disease might result: type 2 (which is seen in
sporadic CJD); type 4 (which causes vCJD) or type 5 (which may cause a
new pattern of disease).

Professor John Collinge, Director of the MRC Prion Unit, which is based
at University College London, said: "These mouse studies give us vital
clues about the behaviour of prions and how they appear to modify and
adapt depending on the genetic makeup of the individual they are infecting.

"We always have to be cautious about making direct comparison to the
human condition, but our work strongly suggests that we can not assume
only those with one genetic profile are vulnerable to BSE infection.

"At this stage it is not possible to say how this should alter estimates
of those likely to become ill, but our findings do suggest we should be
taking steps to draw up a more sophisticated system of categorizing the
disease so that we don't mistake BSE related infection for a version of
sporadic CJD."

For more information call the MRC press office on 020 7 637 6011

Notes to Editors

*The human prion protein comes in two common forms, known as M and V.
Because everyone has two copies of this gene, there are three possible
genetic types: MM, MV and VV.

Paper - Human Prion protein v129 prevent expression of vCJD phenotype -
Science On line 11.11.04

Prions are rogue forms of one of the body's own proteins - known as the
prion protein - which are misshapen. There are several different rogue
or misshapen forms that can infect humans, and these different types of
prions are known as "strains". This is analogous to different strains of
other germs such 'flu virus causing influenza or strains of salmonella
causing different forms of food poisoning for example.

The strain of prion causing vCJD is known as type 4, types 1-3 cause the
different forms of sporadic or classical CJD. Each strain causes a
different pattern or type of disease. It is known that prion strains can
change or "mutate" when they pass between different animals.

The Medical Research Council (MRC) is a national organisation funded by
the UK tax-payer. Its business is medical research aimed at improving
human health; everyone stands to benefit from the outputs. The research
it supports and the scientists it trains meet the needs of the health
services, the pharmaceutical and other health-related industries and the
academic world. MRC has funded work which has led to some of the most
significant discoveries and achievements in medicine in the UK. About
half of the MRC's expenditure of £430 million is invested in its 40
Institutes, Units and Centres. The remaining half goes in the form of
grant support and training awards to individuals and teams in
universities and medical schools.

http://www.mrc.ac.uk/index/public-interest/public-press_office/public-press_releases_2004/public-11_november_2004.htm


I am sincerely,

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

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