Chronic Wasting Disease Near Yellowstone National Park

Environmental Nightmare Unstoppable

Elk winter feed grounds in western Wyoming should be phased out to curb the potential spread of Chronic Wasting Disease (prion disease) in elk. That is what Lloyd Dorsey of the Greater Yellowstone Coalition in Jackson recommends, using information he gathered from Wyoming Game & Fish Department reports.

Chronic wasting disease, or CWD, has been detected 40 miles from Yellowstone National Park and 45 miles from winter elk feedgrounds, according to a coalition map. Chronic wasting disease is a fatal disease of the central nervous system of deer, Rocky Mountain elk and (rarely) moose, according to the Game & Fish.

chronic wasting disease caused by prions

The 2012 department information reveals the farthest western advance of CWD positive deer in Wyoming, yet.

The disease occurs at a higher rate in deer areas than elk areas. Chronic wasting disease might arrive in feed grounds, but it hasn’t so far, and they can’t predict whether it will, said Game & Fish information specialist Al Langston in Cheyenne. But other experts sounded a warning.

“Finally, our results demonstrate that high-density elk populations (10 to 100 elk per kilometer squared) can support relatively high rates of CWD (.10 percent prevalence) that may substantially affect the dynamics of such populations,” stated an 2013 article by Ryan J. Monello and associates in “The Journal of Wildlife Diseases.”

“The good news is that the disease has not been detected at the feedgrounds or national parks yet,” said Bruce Smith, a retired U.S. Fish and Wildlife Service biologist and former biologist at the National Elk Refuge in Jackson. “Managers can still act to responsibly phase out winter feeding of elk and limit the effects of this and other diseases.”

Game & Fish staffers search for the disease by collecting and analyzing wild ungulate lymph nodes, mostly from animals harvested by hunters. Testing is very reliable using lymph nodes. Analyzing live animal samples is not as accurate, Langston said.

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A total of 2,017 deer, elk and moose samples were examined in 2012. Of those samples, 98 tested positive for CWD, including 78 mule deer, six white-tailed deer and 14 elk. New cases of the disease were diagnosed in deer hunt areas 132 (west of Flaming Gorge) and 157 (east of Pavillion) as well as elk hunt area 10 (west of Laramie).

These hunt areas all are bordered by known positive areas or states and are most likely natural extensions of the endemic area, according to a Game & Fish 2013 CWD report.

The state’s only CWD-positive elk are in southeastern Wyoming, but CWD-positive deer do occupy the Big Horn Basin, according to a Game & Fish 2012 map.

No elk harvested in western Wyoming tested positive last year. If those elk had not been killed by hunters, they would have wintered in the feedgrounds, Langston said.

chronic wasting disease and moose

A total of 3,273 deer, elk and moose samples were analyzed in 2011. Of those samples, 109 tested positive for CWD, representing 81 mule deer, 16 white-tailed deer and 12 elk. One new case of the disease was diagnosed in deer hunt area 165 (north of Meeteetse). Area 165 is bordered by known positive areas and likely a natural extension of the endemic area, said a 2012 Game & Fish report.

“Rocky Mountain elk do very well without feedgrounds, for the most part,” Dorsey said.

For example, in the Gros Ventre area there are three feedgrounds, but there also is good winter range. Conflicts could be mitigated.

“We’d be happy to help find resources to build elk-proof fences to help keep elk separate from cattle and horses during winter and spring, and prevent inter-species transmission of brucellosis,” Dorsey said.

About 80 percent of the elk in seven herd units comprising west-central Wyoming use the feedgrounds. Although nobody knows how many, there would be fewer elk without feedgrounds, said Brandon Scurlock, a Game & Fish brucellosis program supervisor in Pinedale.

Typically, the units are at or over population objectives, Dorsey said. As examples, the Jackson herd objective is 11,000 elk. The 2012 estimate was 11,051. The Fall Creek herd objective is 4,400. The 2012 estimate was 4,500. There are 23 feed grounds in western Wyoming. Of those, 22 are managed by the state and one, the National Elk Refuge in Jackson, is run by the U.S. Fish & Wildlife Service.

Brucellosis is endemic in elk populations that visit elk feedgrounds in western Wyoming. It also is found in some elk herds that do not attend elk feedgrounds, but typically at a lower rate, Dorsey said.

Now is the time to phase out the feed grounds before a CWD epidemic occurs in those areas, Dorsey said.

CWD News via http://www.powelltribune.com/news/item/11215-analyst-closing-elk-feedgrounds-will-curb-cwd

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Crossbow Communications specializes in issue management and public affairs. Alzheimer’s disease, Creutzfeldt-Jakob disease, chronic wasting disease and the prion disease epidemic is an area of special expertise. Please contact Gary Chandler to join our coalition for reform gary@crossbow1.com.

Safety Practices for Handling Prions Unsatisfactory

Impossible To Neutralize Prions

(Please note that the following precautions outlined by Michigan State University indicate caution when handling prions, however, in the mind of this blogger, these precautions do not go far enough. The following guidelines suggest that equipment can be decontaminated. It’s well documented that exposed equipment cannot be decontaminated. Therefore, this article outlines further mismanagement in the prion arena.)

Research-related activities involving prions or tissues containing prions have been on the rise at MSU in both the animal health and human health arenas. Because the infectious nature of prions is not well characterized and destruction of these particles goes beyond the techniques typically required for biohazard inactivation, work with these agents requires special considerations for bio-containment to minimize both occupational and environmental exposure risk.

prion disease epidemic

Prions & General Biosafety Recommendations

Prions (proteinaceous infectious particles, an abnormal isoform of a normal cellular protein) cause Creutzfeldt-Jakob disease (CJD), scrapie and other related human and animal neurodegenerative diseases. Human prions are manipulated at Biosafety Level (BSL) 2 or 3, depending on the activity, with most human prions treated as BSL-3 under most experimental conditions. In many instances, BSE prions can also be manipulated at BSL-2, however due to the high probability that BSE prions have been transmitted to humans, certain circumstances may require the use of BSL-3 facilities. All other animal prions are considered BSL-2 pathogens. However, when a prion from one species is inoculated into another the resultant infected animal should be treated according to the guidelines applying to the source of the inoculum. Please see the following table adapted from the BMBL for a list of common mammalian prions and general BSL recommendation.

Note: Biosafety level assignment should be established using a risk assessment that accounts for the nature and host range of the agent, as well as the nature of the procedures and concentration and quantity of the agent. The highest concentration of prions is found in the central nervous system (CNS), and extreme caution must be exerted when handling CNS samples. However prions can also be found in the CSF, lung, liver, kidney, spleen/lymph nodes, placenta. Unfixed samples of brain or spinal cord, as well as other tissues known to contain human prions should be handled at BSL-3. With regards to BSE prions, it is also recommended that animal tissue samples (e.g., brain, spinal cord) known or strongly suspected to contain prions be handled at BSL-3 (BMBL 2007). For other samples, the level of containment will depend on the type of tissue handled, the nature of the manipulation and the amount of material handled (MSDS 1997).

mad cow disease and prions

Formaldehyde or formalin-fixed, glutaraldehyde-fixed and paraffin-embedded tissues, particularly of the brain, remain infectious for long periods, if not indefinitely (BMBL 2007, WHO 2000). They should be handled cautiously as fresh materials from fixation through embedding, sectioning, staining and mounting on slides, unless treated with 95% formic acid (WHO 2000).

Although there are no documented laboratory-acquired prion infections, the primary hazard is from accidental parenteral inoculation or ingestion. Cuts and punctures should be avoided and the use of sharp knives, scalpels, blades and needles should be minimized. If the use of sharps cannot be avoided, cut-resistant gloves should be worn (CFIA 2005).

Wherever possible, the laboratory and equipment used for work with prions should be dedicated to that task alone. All employees should be informed and aware that prion research is being conducted in the lab. The entrance to the lab should allow for the separation of PPE/lab clothing and staff clothing. An exposure protocol should be developed, posted and communicated to all employees (CFIA 2005, UCSD 2002). Procedures should be in place for the effective decontamination of all waste, re-usable equipment, surfaces and other lab space (CFIA 2005, UCSD 2002).

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Working with Prion-Risk Materials

At this time, work with prion-risk materials at MSU is limited to research and diagnostic laboratory applications. Therefore, this guidance document applies to these procedures only. Guidelines for use of prion-risk materials in conjunction with live animals will be developed if needed. Therefore, if future project plans call for use of live animals and prion-risk materials, please notify the MSU Biosafety Officer at the proposal-writing stage to perform a risk assessment and identify containment requirements.

Procedures involving the manipulation of animal tissues that are from known or suspected scrapie or CWD cases must be handled under BSL-2 conditions as a minimum standard. Procedures involving manipulation of human tissues that are known or suspected cases of CJD must typically be handled at BSL-3 conditions, unless a risk assessment completed in conjunction with an ORCBS Biosafety Professional allows for BSL-2 facilities and procedures. In general, procedures that involve aerosolization or vigorous disruption of the material (i.e., centrifugation, sonication, laser dissection) bear the greatest risk to personnel and the environment and will require special consideration for containment at both biosafety levels.

Additionally, the following specific measures should be implemented for all work with prion-risk materials:

1. Access to the laboratory must be restricted to trained personnel when work is being conducted on tissue.

2. Personnel working with prion-risk materials must complete Biosafety Principles for Animal Users through the ORCBS, as well as complete on-site training relative to the nature of the prion in use, routes of transmission, and specific hazards of the tissue handling process. Written procedures and training records should be kept as outlined in the BMBL.

3. Personnel must wear gloves and gowns while handling tissues that are potentially contaminated. All protective clothing must be removed before leaving the laboratory.

4. All fixed, non-fixed, or frozen tissues must be contained within watertight containers. Containers must be individually labeled with the universal biohazard symbol or placed in a secondary container (i.e., a tray with sides) that is labeled with the universal biohazard symbol.

5. Sonication or homogenization of tissues must be performed in a properly certified Class II biosafety cabinet.

6. Microtome blades and knives used for cutting tissue must be cleaned with an instrument that does not put the hand or finger of the operator in or near contact with the blade.

7. Disposable, absorbent pads or disposable trays should be used whenever possible to help confine contamination and to facilitate cleanup and disinfection.

8. The following practices should be followed when using reusable instruments:

  • Instruments should be kept wet until cleaned and decontaminated;
  • Instruments should be cleaned as soon as possible to prevent drying of material;
  • Do not mix instruments used on materials potentially infected with prions with those instruments used for other purposes;
  • Instruments that will be cleaned in a dishwasher must be decontaminated first and the washer must be run through an empty cycle before being used for other instruments;

9. The following provisions for decontamination of wastes, reusable instruments and contaminated surfaces must be followed to assure effective inactivation of prions:

  • Liquid waste may be treated in the following ways:
  • Mix with NaOH for a final concentration of 1.0 N NaOH and hold at room temperature for 1 hour; or
  • Mix with bleach for a final concentration of 20,000 ppm available chlorine and hold at room temperature for 1 hour This waste should be stored in a chemical fume hood for the duration of the treatment period. After the treatment period, liquid waste may be neutralized and discharged to the sewer by way of the lab sink, or disposed of through the ORCBS as liquid chemical waste.
  • Contaminated surfaces may be treated in the following ways:
  • Bleach solution (20,000 ppm available chlorine) for 1 hour; or 1N NaOH for 1 hour
  • After treatment, surfaces should be thoroughly rinsed with clear water.
  • Contaminated reusable instruments may be treated in the following ways:
  • Immerse in 1N NaOH or sodium hypochlorite (20,000 ppm available chlorine) for 1 hour, transfer to water, autoclave (gravity displacement) at 121°C for 1 hour (BMBL 2007, WHO 2000);
  • Immerse in 1N NaOH or sodium hypochlorite (20,000 ppm available chlorine) 1 hour, rinse with water, autoclave at 121°C for 1 hour (gravity displacement) or at 134 °C for I hour (porous load) (BMBL 2007, WHO 2000); or
  • Immerse in sodium hypochlorite solution with 20,000 ppm available chlorine (preferred) or 1N NaOH (alternative) for 1 hour (WHO 2000)
  • All contaminated dry waste should be picked up for incineration. Prioncontaminated sharps waste must be identified as “prion contaminated sharps- for incineration only” on the hazardous waste pickup request to assure incineration of these materials. Contact the ORCBS Biosafety Staff for further assistance regarding treatment and disposal.

10. Intact skin exposure to prion-risk materials should be followed by washing with 1N NaOH or 10% bleach for two to three minutes, followed by extensive washing with water. For needle sticks or lacerations, gently encourage bleeding, wash with warm soapy water, rinse, dry and cover with a waterproof dressing. In the event of a splash to the eye, rinse the affected eye with copious amounts of water or saline only. In the instance of a splash or puncture, the exposed individual should then report to Olin Urgent Care for follow-up through MSU Occupational Health.

11. The Principal Investigator (PI) must assure that all spills or exposures involving prion- risk materials are managed with the proper procedures. Additionally, these events should be reported to the MSU Biosafety Officer as soon as possible for follow-up and assistance with actions to reduce future occurrences.

12. Prion-risk materials may be subject to permit requirements for shipment and receipt. USDA permits apply to interstate and international shipment of anima-related materials capable of transmitting infection. CDC permits apply to import of materials that are potentially infectious to humans. Additionally, shipment of these materials requires specific training for the shipper. Contact the ORCBS Biosafety Staff for further information.

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Notes on chemical disinfection

Sodium Hydroxide (NaOH, or soda lye): Be familiar with and observe safety guidelines for working with NaOH. 1N NaOH is a solution of 40 g NaOH in 1 liter of water. 1 N NaOH readily reacts with CO2 in air to form carbonates that neutralize NaOH and diminish its disinfective properties. 10 N NaOH solutions do not absorb CO2, therefore, 1N NaOH working solutions should be prepared fresh for each use either from solid NaOH pellets, or by dilution of 10 N NaOH stock solutions.

Sodium hypochlorite (NaOCl solution, or bleach): Be familiar with and observe safety guidelines for working with sodium hypochlorite. Household or industrial strength bleach is sold at different concentrations so a standard dilution cannot be specified. Efficacy depends upon the concentration of available chlorine and should be 20,000 ppm available chlorine. These solutions are corrosive and appropriate personal protective equipment must be worn when preparing and using them.

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BIOSAFETY LEVEL 2

Biosafety Level 2 builds upon BSL-1. BSL-2 is suitable for work involving agents that pose moderate hazards to personnel and the environment. It differs from BSL-1 in that 1) laboratory personnel have specific training in handling pathogenic agents and are supervised by scientists competent in handling infectious agents and associated procedures; 2) access to the laboratory is restricted when work is being conducted; and

3) all procedures in which infectious aerosols or splashes may be created are conducted in BSCs or other physical containment equipment.

The following standard and special practices, safety equipment, and facility requirements

apply to BSL-2:

A. Standard Microbiological Practices

1. The laboratory supervisor must enforce the institutional policies that control access to the laboratory.

2. Persons must wash their hands after working with potentially hazardous materials and before leaving the laboratory.

3. Eating, drinking, smoking, handling contact lenses, applying cosmetics, and storing food for human consumption must not be permitted in laboratory areas. Food must be stored outside the laboratory area in cabinets or refrigerators designated and used for this purpose.

4. Mouth pipetting is prohibited; mechanical pipetting devices must be used.

5. Policies for the safe handling of sharps, such as needles, scalpels, pipettes, and broken glassware must be developed and implemented. Whenever practical, laboratory supervisors should adopt improved engineering and work practice controls that reduce risk of sharps injuries.

Precautions, including those listed below, must always be taken with sharp items. These include:

a. Careful management of needles and other sharps are of primary importance. Needles must not be bent, sheared, broken, recapped, removed from disposable syringes, or otherwise manipulated by hand before disposal.

b. Used disposable needles and syringes must be carefully placed in conveniently located puncture-resistant containers used for sharps disposal.

c. Non-disposable sharps must be placed in a hard walled container for transport to a processing area for decontamination, preferably by autoclaving.

d. Broken glassware must not be handled directly. Instead, it must be removed using a brush and dustpan, tongs, or forceps. Plasticware should be substituted for glassware whenever possible.

6. Perform all procedures to minimize the creation of splashes and/or aerosols.

7. Decontaminate work surfaces after completion of work and after any spill or splash of potentially infectious material with appropriate disinfectant.

8. Decontaminate all cultures, stocks, and other potentially infectious materials before disposal using an effective method. Depending on where the decontamination will be performed, the following methods should be used prior to transport:

a. Materials to be decontaminated outside of the immediate laboratory must be placed in a durable, leak proof container and secured for transport.

b. Materials to be removed from the facility for decontamination must be packed in accordance with applicable local, state, and federal regulations.

9. A sign incorporating the universal biohazard symbol must be posted at the entrance to the laboratory when infectious agents are present. Posted information must include: the laboratory’s biosafety level, the supervisor’s name (or other responsible personnel), telephone number, and required procedures for entering and exiting the laboratory. Agent information should be posted in accordance with the institutional policy.

10. An effective integrated pest management program is required. See Appendix G.

11. The laboratory supervisor must ensure that laboratory personnel receive appropriate training regarding their duties, the necessary precautions to prevent exposures, and exposure evaluation procedures. Personnel must receive annual updates or additional training when procedural or policy changes occur. Personal health status may impact an individual’s susceptibility to infection, ability to receive immunizations or prophylactic interventions. Therefore, all laboratory personnel and particularly women of child-bearing age should be provided with information regarding immune competence and conditions that may predispose them to infection. Individuals having these conditions should be encouraged to self-identify to the institution’s healthcare provider for appropriate counseling and guidance.

B. Special Practices

1. All persons entering the laboratory must be advised of the potential hazards and meet specific entry/exit requirements.

2. Laboratory personnel must be provided medical surveillance and offered appropriate immunizations for agents handled or potentially present in the laboratory.

3. Each institution must establish policies and procedures describing the collection and storage of serum samples from at-risk personnel.

4. A laboratory-specific biosafety manual must be prepared and adopted as policy. The biosafety manual must be available and accessible.

5. The laboratory supervisor must ensure that laboratory personnel demonstrate proficiency in standard and special microbiological practices before working with BSL-2 agents.

6. Potentially infectious materials must be placed in a durable, leak proof container during collection, handling, processing, storage, or transport within a facility.

7. Laboratory equipment should be routinely decontaminated, as well as, after spills, splashes, or other potential contamination.

a. Spills involving infectious materials must be contained, decontaminated, and cleaned up by staff properly trained and equipped to work with infectious material.

b. Equipment must be decontaminated before repair, maintenance, or removal from the laboratory.

8. Incidents that may result in exposure to infectious materials must be immediately evaluated and treated according to procedures described in the laboratory biosafety safety manual. All such incidents must be reported to the laboratory supervisor. Medical evaluation, surveillance, and treatment should be provided and appropriate records maintained.

9. Animals and plants not associated with the work being performed must not be permitted in the laboratory.

10. All procedures involving the manipulation of infectious materials that may generate an aerosol should be conducted within a BSC or other physical containment devices.

C. Safety Equipment (Primary Barriers and Personal Protective Equipment)

1. Properly maintained BSCs (preferably Class II), other appropriate personal protective equipment, or other physical containment devices must be used whenever:

a. Procedures with a potential for creating infectious aerosols or splashes are conducted. These may include pipetting, centrifuging, grinding, blending, shaking, mixing, sonicating, opening containers of infectious materials, inoculating animals intranasally, and harvesting infected tissues from animals or eggs.

b. High concentrations or large volumes of infectious agents are used. Such materials may be centrifuged in the open laboratory using sealed rotor heads or centrifuge safety cups.

2. Protective laboratory coats, gowns, smocks, or uniforms designated for laboratory use must be worn while working with hazardous materials. Remove protective clothing before leaving for non-laboratory areas (e.g., cafeteria, library, administrative offices). Dispose of protective clothing appropriately, or deposit it for laundering by the institution. It is recommended that laboratory clothing not be taken home.

3. Eye and face protection (goggles, mask, face shield or other splatter guard) is used for anticipated splashes or sprays of infectious or other hazardous materials when the microorganisms must be handled outside the BSC or containment device. Eye and face protection must be disposed of with other contaminated laboratory waste or decontaminated before reuse. Persons who wear contact lenses in laboratories should also wear eye protection.

4. Gloves must be worn to protect hands from exposure to hazardous materials. Glove selection should be based on an appropriate risk assessment. Alternatives to latex gloves should be available. Gloves must not be worn outside the laboratory. In addition, BSL-2 laboratory workers should:

a. Change gloves when contaminated, integrity has been compromised, or when otherwise necessary. Wear two pairs of gloves when appropriate.

b. Remove gloves and wash hands when work with hazardous materials has been completed and before leaving the laboratory.

c. Do not wash or reuse disposable gloves. Dispose of used gloves with other contaminated laboratory waste. Hand washing protocols must be rigorously followed.

5. Eye, face and respiratory protection should be used in rooms containing infected animals as determined by the risk assessment.

D. Laboratory Facilities (Secondary Barriers)

1. Laboratory doors should be self-closing and have locks in accordance with the institutional policies.

2. Laboratories must have a sink for hand washing. The sink may be manually, handsfree, or automatically operated. It should be located near the exit door.

3. The laboratory should be designed so that it can be easily cleaned and decontaminated. Carpets and rugs in laboratories are not permitted.

4. Laboratory furniture must be capable of supporting anticipated loads and uses. Spaces between benches, cabinets, and equipment should be accessible for cleaning.

a. Bench tops must be impervious to water and resistant to heat, organic solvents, acids, alkalis, and other chemicals.

b. Chairs used in laboratory work must be covered with a non-porous material that can be easily cleaned and decontaminated with appropriate disinfectant.

5. Laboratory windows that open to the exterior are not recommended. However, if a laboratory does have windows that open to the exterior, they must be fitted with screens.

6. BSCs must be installed so that fluctuations of the room air supply and exhaust do not interfere with proper operations. BSCs should be located away from doors, windows that can be opened, heavily traveled laboratory areas, and other possible airflow disruptions.

7. Vacuum lines should be protected with High Efficiency Particilate Air (HEPA) filters, or their equivalent. Filters must be replaced as needed. Liquid disinfectant traps may be required.

8. An eyewash station must be readily available.

9. There are no specific requirements on ventilation systems. However, planning of new facilities should consider mechanical ventilation systems that provide an inward flow of air without recirculation to spaces outside of the laboratory.

10. HEPA filtered exhaust air from a Class II BSC can be safely re-circulated back into the laboratory environment if the cabinet is tested and certified at least annually and operated according to manufacturer’s recommendations. BSCs can also be connected to the laboratory exhaust system by either a thimble (canopy) connection or a direct (hard) connection. Provisions to assure proper safety cabinet performance and air system operation must be verified.

11. A method for decontaminating all laboratory wastes should be available in the facility (e.g., autoclave, chemical disinfection, incineration, or other validated decontamination method).

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BIOSAFETY LEVEL 3

Biosafety Level 3 is applicable to clinical, diagnostic, teaching, research, or production facilities where work is performed with indigenous or exotic agents that may cause serious or potentially lethal disease through inhalation route exposure. Laboratory personnel must receive specific training in handling pathogenic and potentially lethal agents, and must be supervised by scientists competent in handling infectious agents and associated procedures. All procedures involving the manipulation of infectious materials must be conducted within BSCs, other physical containment devices, or by personnel wearing appropriate personal protective equipment. A BSL-3 laboratory has special engineering and design features.

The following standard and special safety practices, equipment, and facility requirements apply to BSL-3:

A. Standard Microbiological Practices

1. The laboratory supervisor must enforce the institutional policies that control access to the laboratory.

2. Persons must wash their hands after working with potentially hazardous materials and before leaving the laboratory.

3. Eating, drinking, smoking, handling contact lenses, applying cosmetics, and storing food for human consumption must not be permitted in laboratory areas. Food must be stored outside the laboratory area in cabinets or refrigerators designated and used for this purpose.

4. Mouth pipetting is prohibited; mechanical pipetting devices must be used.

5. Policies for the safe handling of sharps, such as needles, scalpels, pipettes, and broken glassware must be developed and implemented. Whenever practical, laboratory supervisors should adopt improved engineering and work practice controls that reduce risk of sharps injuries. Precautions, including those listed below, must always be taken with sharp items. These include:

a. Careful management of needles and other sharps are of primary importance. Needles must not be bent, sheared, broken, recapped, removed from disposable syringes, or otherwise manipulated by hand before disposal.

b. Used disposable needles and syringes must be carefully placed in conveniently located puncture-resistant containers used for sharps disposal.

c. Non-disposable sharps must be placed in a hard walled container for transport to a processing area for decontamination, preferably by autoclaving.

d. Broken glassware must not be handled directly. Instead, it must be removed using a brush and dustpan, tongs, or forceps. Plasticware should be substituted for glassware whenever possible.

6. Perform all procedures to minimize the creation of splashes and/or aerosols.

7. Decontaminate work surfaces after completion of work and after any spill or splash of potentially infectious material with appropriate disinfectant.

8. Decontaminate all cultures, stocks, and other potentially infectious materials before disposal using an effective method. A method for decontaminating all laboratory wastes should be available in the facility, preferably within the laboratory (e.g., autoclave, chemical disinfection, incineration, or other validated decontamination method). Depending on where the decontamination will be performed, the following methods should be used prior to transport:

a. Materials to be decontaminated outside of the immediate laboratory must be placed in a durable, leak proof container and secured for transport.

b. Materials to be removed from the facility for decontamination must be packed in accordance with applicable local, state, and federal regulations.

9. A sign incorporating the universal biohazard symbol must be posted at the entrance to the laboratory when infectious agents are present. Posted information must include the laboratory’s biosafety level, the supervisor’s name (or other responsible personnel), telephone number, and required procedures for entering and exiting the laboratory. Agent information should be posted in accordance with the institutional policy.

10. An effective integrated pest management program is required. See Appendix G.

11. The laboratory supervisor must ensure that laboratory personnel receive appropriate training regarding their duties, the necessary precautions to prevent exposures, and exposure evaluation procedures. Personnel must receive annual updates or additional training when procedural or policy changes occur. Personal health status may impact an individual’s susceptibility to infection, ability to receive immunizations or prophylactic interventions. Therefore, all laboratory personnel and particularly women of child-bearing age should be provided with information regarding immune competence and conditions that may predispose them to infection. Individuals having these conditions should be encouraged to self-identify to the institution’s healthcare provider for appropriate counseling and guidance.

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B. Special Practices

1. All persons entering the laboratory must be advised of the potential hazards and meet specific entry/exit requirements.

2. Laboratory personnel must be provided medical surveillance and offered appropriate immunizations for agents handled or potentially present in the laboratory.

3. Each institution must establish policies and procedures describing the collection and storage of serum samples from at-risk personnel.

4. A laboratory-specific biosafety manual must be prepared and adopted as policy. The biosafety manual must be available and accessible.

5. The laboratory supervisor must ensure that laboratory personnel demonstrate proficiency in standard and special microbiological practices before working with BSL-3 agents.

6. Potentially infectious materials must be placed in a durable, leak proof container during collection, handling, processing, storage, or transport within a facility.

7. Laboratory equipment should be routinely decontaminated, as well as, after spills, splashes, or other potential contamination.

a. Spills involving infectious materials must be contained, decontaminated, and cleaned up by staff properly trained and equipped to work with infectious material.

b. Equipment must be decontaminated before repair, maintenance, or removal from the laboratory.

8. Incidents that may result in exposure to infectious materials must be immediately evaluated and treated according to procedures described in the laboratory biosafety safety manual. All such incidents must be reported to the laboratory supervisor. Medical evaluation, surveillance, and treatment should be provided and appropriate records maintained.

9. Animals and plants not associated with the work being performed must not be permitted in the laboratory.

10. All procedures involving the manipulation of infectious materials must be conducted within a BSC, or other physical containment devices. No work with open vessels is conducted on the bench. When a procedure cannot be performed within a BSC, a combination of personal protective equipment and other containment devices, such as a centrifuge safety cup or sealed rotor, must be used.

C. Safety Equipment (Primary Barriers and Personal Protective Equipment)

1. All procedures involving the manipulation of infectious materials must be conducted within a BSC (preferably Class II or Class III), or other physical containment devices.

2. Protective laboratory clothing with a solid-front such as tie-back or wraparound gowns, scrub suits, or coveralls are worn by workers when in the laboratory. Protective clothing is not worn outside of the laboratory. Reusable clothing is decontaminated with appropriate disinfectant before being laundered. Clothing is changed when contaminated.

3. Eye and face protection (goggles, mask, face shield or other splatter guard) is used for anticipated splashes or sprays of infectious or other hazardous materials. Eye and face protection must be disposed of with other contaminated laboratory waste or decontaminated before reuse. Persons who wear contact lenses in laboratories must also wear eye protection.

4. Gloves must be worn to protect hands from exposure to hazardous materials. Glove selection should be based on an appropriate risk assessment. Alternatives to latex gloves should be available. Gloves must not be worn outside the laboratory. In addition, BSL-3 laboratory workers should:

a. Change gloves when contaminated, integrity has been compromised, or when otherwise necessary. Wear two pairs of gloves when appropriate.

b. Remove gloves and wash hands when work with hazardous materials has been completed and before leaving the laboratory.

c. Do not wash or reuse disposable gloves. Dispose of used gloves with other contaminated laboratory waste. Hand washing protocols must be rigorously followed.

5. Eye, face, and respiratory protection must be used in rooms containing infected animals.

D. Laboratory Facilities (Secondary Barriers)

1. Laboratory doors must be self closing and have locks in accordance with the institutional policies. The laboratory must be separated from areas that are open to unrestricted traffic flow within the building. Access to the laboratory is restricted to entry by a series of two self-closing doors. A clothing change room (anteroom) may be included in the passageway between the two self-closing doors.

2. Laboratories must have a sink for hand washing. The sink must be hands-free or automatically operated. It should be located near the exit door. If the laboratory is segregated into different laboratories, a sink must also be available for hand washing in each zone. Additional sinks may be required as determined by the risk assessment.

3. The laboratory must be designed so that it can be easily cleaned and decontaminated. Carpets and rugs are not permitted. Seams, floors, walls, and ceiling surfaces should be sealed. Spaces around doors and ventilation openings should be capable of being sealed to facilitate space decontamination.

a. Floors must be slip resistant, impervious to liquids, and resistant to chemicals. Consideration should be given to the installation of seamless, sealed, resilient or poured floors, with integral cove bases.

b. Walls should be constructed to produce a sealed smooth finish that can be easily cleaned and decontaminated.

c. Ceilings should be constructed, sealed, and finished in the same general manner as walls. Decontamination of the entire laboratory should be considered when there has been gross contamination of the space, significant changes in laboratory usage, for major renovations, or maintenance shut downs. Selection of the appropriate materials and methods used to decontaminate the laboratory must be based on the risk assessment of the biological agents in use.

4. Laboratory furniture must be capable of supporting anticipated loads and uses. Spaces between benches, cabinets, and equipment must be accessible for cleaning.

a. Bench tops must be impervious to water and resistant to heat, organic solvents, acids, alkalis, and other chemicals.

b. Chairs used in laboratory work must be covered with a non-porous material that can be easily cleaned and decontaminated with appropriate disinfectant.

5. All windows in the laboratory must be sealed.

6. BSCs must be installed so that fluctuations of the room air supply and exhaust do not interfere with proper operations. BSCs should be located away from doors, heavily traveled laboratory areas, and other possible airflow disruptions.

7. Vacuum lines must be protected with HEPA filters, or their equivalent. Filters must be replaced as needed. Liquid disinfectant traps may be required.

8. An eyewash station must be readily available in the laboratory.

9. A ducted air ventilation system is required. This system must provide sustained directional airflow by drawing air into the laboratory from “clean” areas toward “potentially contaminated” areas. The laboratory shall be designed such that under failure conditions the airflow will not be reversed.

a. Laboratory personnel must be able to verify directional air flow. A visual monitoring device which confirms directional air flow must be provided at the laboratory entry. Audible alarms should be considered to notify personnel of air flow disruption.

b. The laboratory exhaust air must not re-circulate to any other area of the building.

c. The laboratory building exhaust air should be dispersed away from occupied areas and from building air intake locations or the exhaust air must be HEPA filtered.

10. HEPA filtered exhaust air from a Class II BSC can be safely re-circulated into the laboratory environment if the cabinet is tested and certified at least annually and operated according to manufacturer’s recommendations. BSCs can also be connected to the laboratory exhaust system by either a thimble (canopy) connection or a direct (hard) connection. Provisions to assure proper safety cabinet performance and air system operation must be verified. BSCs should be certified at least annually to assure correct performance. Class III BSCs must be directly (hard) connected up through the second exhaust HEPA filter of the cabinet. Supply air must be provided in such a manner that prevents positive pressurization of the cabinet.

11. A method for decontaminating all laboratory wastes should be available in the facility, preferably within the laboratory (e.g., autoclave, chemical disinfection, incineration, or other validated decontamination method).

12. Equipment that may produce infectious aerosols must be contained in devices that exhaust air through HEPA filtration or other equivalent technology before being discharged into the laboratory. These HEPA filters should be tested and/or replaced at least annually.

13. Facility design consideration should be given to means of decontaminating large pieces of equipment before removal from the laboratory.

14. Enhanced environmental and personal protection may be required by the agent summary statement, risk assessment, or applicable local, state, or federal regulations. These laboratory enhancements may include, for example, one or more of the following; an anteroom for clean storage of equipment and supplies with dress-in, shower-out capabilities; gas tight dampers to facilitate laboratory isolation; final HEPA filtration of the laboratory exhaust air; laboratory effluent decontamination; and advanced access control devices such as biometrics. HEPA filter housings should have gas-tight isolation dampers; decontamination ports; and/or bag-in/bag-out (with appropriate decontamination procedures) capability. The HEPA filter housing should allow for leak testing of each filter and assembly. The filters and the housing should be certified at least annually.

15. The BSL-3 facility design, operational parameters, and procedures must be verified and documented prior to operation. Facilities must be re-verified and documented at least annually.

References

AAVLD. 2004. Practices for Handling Suspect Biosafety Level 2 Animal TSE. Veterinary Laboratory Diagnosticians’, Waste disposal and Pathology Committee, p. 3-4 BMBL. 2007. Section VIII-H. Prion Diseases. Biosafety in Microbiological and Biomedical Laboratories, 5th ed. Centers for Disease Control and Prevention, National Institute of Health, U.S. Department of Health and Human Services CFIA. 2005. Containment Standards for Laboratories, Animal Facilities and Post Morten Rooms Handling Prion Disease Agents. Biohazard Containment and Safety Unit, Canadian Food Inspection Agency, http://www.inspection.gc.ca/english/sci/bio/anima/consult/prionse.shtml

MSDS. 1997. Creutzfeldt-Jakob agent, Kuru agent. Material Safety Data Sheet-Infectious Substances. Office of Laboratory Security, Population and Public Health Branch, Health Canada, http://www.hc-sc.gc.ca/pphb-dgspsp/msds-ftss/msds45e.html UCSD. 2002. Prion Research Guidelines. University of California, San Diego, http://www.neurosci.ucsd.edu/Safety_Docs/UCSD_Prion_FactSheet.htm

WHO. 2000. WHO infection control guidelines for transmissible spongiform encephalopathies. Report of a WHO consultation, Geneva, Switzerland, 23-26 March 1999, http://www.who.int/csr/resources/publications/bse/whocdscsraph2003.pdf

public relations firm and public affairs firm Denver and Phoenix

Crossbow Communications specializes in issue management and public affairs. Alzheimer’s disease, Creutzfeldt-Jakob disease, chronic wasting disease and the prion disease epidemic is an area special expertise. Please contact Gary Chandler to join our coalition for reform gary@crossbow1.com.

Incinerating Prions A Bad Practice

Prions Can Become Aerosol Agent

By James B. Woodward

February 19, 2004

Mr. Jonathan Akins
Environmental Engineer
Air Pollution Control Division – Stationary Sources Program
Colorado Department of Public Health & Environment
4300 Cherry Creek Drive South
Denver, Colorado 80246-1530

Subject: Draft Permit #03ME0664 issued to Colorado State University (CSU) for a bio-medical waste incinerator for disposal of pathological waste, some of which could potentially be infected with transmissible spongiform encephalopathies (TSEs), located at 425 29 Road, Grand Junction, Mesa County, Colorado.

Dear Mr. Akins:

The following are my comments concerning the air permit for the proposed Grand Junction incinerator.  My comments are primarily concerned with the question of whether this incinerator will effectively destroy the agents thought to cause Transmissible Spongiform Encephalopathies (TSEs). Since I believe there is no assurance infective material will not be released into the environment, I request that the Air Pollution Control Division prohibit the disposal of waste contaminated or potentially contaminated with TSEs in this proposed incineration facility.

chronic wasting disease cause

The proposed incinerator will be used to dispose of deer and elk heads (and perhaps carcasses) infected or potentially infected with Chronic Wasting Disease (CWD).  If the
facility is permitted to burn TSE-infected tissues, the possibility exists that cattle with Bovine Spongiform Encephalopathy (BSE) or the newly discovered Bovine Amyloidotic Spongiform Encephalopathy (BASE)[1], and/or sheep with scrapie may be disposed of in this incinerator as well.

Surprisingly, the Colorado Department of Public Health & Environment has no departmental rules, regulations, policies, guidelines, and/or recommendations regarding the safe and effective disposal of TSE-contaminated animal carcasses and tissues.  Over the past several months I have submitted Colorado Open Records Act requests asking for any such records or documents.  None have been produced.  Given the department’s lack of regulatory guidance on this matter and the scientific uncertainties surrounding cross-species transmission of TSEs, it would appear to be premature and irresponsible to allow burning of TSE-contaminated wastes in this proposed facility.

The draft permit requires an afterburner temperature of 1800° Fahrenheit  (982° Celsius) with a retention time of two seconds.  As you are aware, there is no scientific data suggesting that these time and temperature parameters will successfully eliminate detectable TSE infectivity.  The parameters are drawn from a 1997 risk assessment prepared for the U.K. Environment Agency by the consulting firm Det Norske Veritas Limited (DNV).  The report looked at the risks from disposing of BSE infected cattle in animal carcass incinerators, specifically the Vetspeed incinerator plant in Cambridge.  The Vetspeed incinerator has approximately twice the capacity of the proposed Grand
Junction unit.  In addition, the Vetspeed incinerator uses a water-spray gas scrubbing unit for removal of particulates, which the study explains is one of the main protective
measures against incomplete combustion.[2]  The proposed Grand Junction incinerator would have no such pollution control equipment.

It is curious that the Colorado Department of Public Health & Environment would utilize the parameters from this study since the department apparently does not possess a copy of the actual study.  The department seems to be relying on a brief excerpt of the study contained in a later report by the European Commission’s Scientific Steering Committee
(EC-SSC)[3].  A careful reading of the actual study reveals that the recommended conditions of operation, 850°C for at least two seconds, are not grounded in any direct scientific evidence.  The authors state: “No experimental data are available on the effect of incineration on BSE infectivity as such.”

The typical method of testing for residual TSE infectivity is the bioassay.  Suspect tissue or material is injected into the brains of test animals.  The animals are monitored
for clinical disease symptoms and are later autopsied and tested for evidence of a TSE.  The DNV study did not use the bioassay to test incinerator ash or emissions.  Rather, they used a surrogate measurement: the total protein content remaining in the ash.  The theory is that, since the infective agent is thought to be a protein, the reduction in
infectivity will be in proportion to the reduction in protein content.

In a 2003 report, the EC-SSC looked at this methodology and concluded that data to date suggest the assumption that TSE degradation is proportional to the degradation of other
proteins is not necessarily justified.  The heat resistance of the TSE agent may simply be greater than other proteins.

The department’s reliance on the DNV study for minimum time/temperature parameters for TSE waste incinerators may be misplaced.  The study provides no direct evidence or
experimental data supporting the parameters.  And it is unclear why the department has disregarded the DNV recommendation calling for the use of pollution control equipment to remove potentially infective particulates.

Below is additional information describing the resistance of TSE agents to typical inactivation methods, problems associated with incineration, the alternative disposal
method of alkaline tissue digestion, and cross species transmission of TSEs (particularly CWD).

Prions and Prusiner win Nobel Prize

TSE Inactivation Impossible

Writing in a study on prion transmission, Dr. C. Weissmann of the Medical Research Council Prion Unit of the Institute of Neurology in London stated:

“A striking feature of prions is their extraordinary resistance to conventional sterilization procedures, and their capacity to bind to surfaces of metal and plastic
without losing infectivity.”

The Centers for Disease Control and Prevention reports that “Prions are characterized by extreme resistance to conventional inactivation procedures including irradiation,
boiling, dry heat, and chemicals.”

The World Health Organization (WHO) writes, “TSE agents are unusually resistant to disinfection and sterilization by most of the physical and chemical methods in common use for decontamination of infectious pathogens.”  The WHO goes on to note “infectivity is strongly stabilized by drying” and that “contaminated materials should be kept wet between the time of use and disinfection by immersion in chemical disinfectants.”[9]

In a scientific study on the heat resistance of the scrapie agent, Dr. Paul Brown observed that TSE agents “are notoriously resistant to most physical and chemical methods used for inactivating pathogens, including heat”.[10]  Dr. Brown is a leading authority on prion diseases and prion inactivation.  A 1998 article by Dr. Brown in the Lancet includes the following discussion of prion inactivation:

“The agents that cause TSE have been known almost since their discovery to have awesome resistance to methods that quickly and easily inactivate most other pathogens…TSE agents are very resistant to virtually every imaginable method of inactivation, and those methods found to be most effective may, in one test or another, fail to sterilise. It seems that even when most infectious particles succumb to an inactivating process, there may remain a small subpopulation of particles that exhibit an extraordinary capacity to withstand inactivation, and that, with appropriate testing, will be found to retain the ability to transmit disease.”

Dr. Brown’s discussion of heat resistant subpopulations refers to experiments by Dr. David Taylor, who is perhaps the world’s leading expert on prion inactivation.  Dr.
Taylor published a study in 1998 showing that during heat inactivation, small subpopulations of TSE agents can become rapidly heat-fixed, and that these thermostable
subpopulations may survive to resist further attempts at inactivation.  The resistant subpopulations can be differentiated by their longer incubation periods in test animals.

In a study on the effect of dry heat on the scrapie agent, Dr. Taylor notes that prions “possess a number of properties which differentiate them from conventional microorganisms, including an exceptional resistance to inactivation by chemical and physical methods”.

The most relevant study on heat resistance of TSE agents was done by Dr. Paul Brown et al., published in 2000.  Brown exposed one-gram samples of scrapie-infected hamster brains to various time and temperature parameters.  The resulting samples were injected intracerebrally into healthy hamsters to test for residual infectivity.  Samples exposed to 600°C and 1000°C for 5 minutes resulted in no detectable infectivity.  A sample exposed to 600°C for 15 minutes, however, infected 5 of 18 hamsters.

The fact that 5 of the test animals became infected is remarkable, since it seems likely that exposure to 600°C for 15 minutes would decompose all organic compounds.  This
enigmatic result led Brown and colleagues to propose various explanations.  They note “combustion is a series of pyrolysis and oxidation reactions that proceed rapidly but
incompletely,” and that 600°C is a “comparatively low combustion temperature”.

They theorize that incomplete combustion may have introduced elemental carbon into the combustion residues, and carbon has been reported to partially protect TSE infectivity.  The researchers observed that only at 1000°C did it appear that most of the carbon residue had been oxidized.  The most interesting theory proposed by Dr. Brown is that the heat created an inorganic replica of the prion’s molecular geometry.  This inorganic “fossil template” could mimic the infectivity of the scrapie agent.[15]

Although the study’s authors write that the results suggest that such an inorganic template would have a decomposition point near 600°C, the fact is that this is a guess.
Measurable infectivity was found at 600°C and none was detected at 1000°C.  No samples were exposed to intermediate temperatures.

Incineration Of Deer With CWD

Regarding incineration, the European Commission’s Scientific Steering Committee (EC-SSC) concludes that:

“With respect to TSEs, it is generally assumed that incineration is a completely effective method for destroying TSE-like agents.  However, there is no direct evidence for this.  The dry heat experiments described in the literature may not be completely relevant to incineration because exposure to dry heat does not involve oxidative combustion, as occurs during incineration.”

“The possibility that incineration might not be completely effective is clearly being considered.  For example, after incinerating materials that could be TSE-infected, the USDA soaks the resulting ash in sodium hydroxide for two weeks before disposal.”

The EC-SSC’s “Opinion on the use of small incinerators for BSE risk reduction,” dated January 16-17, 2003 notes the following:

1. Because of variability in incinerator design and performance characteristics, each incinerator facility needs to be the subject of a specific risk assessment.

2. There is no direct data on the TSE levels that may occur in airborne emissions and residual ash from incinerators.

3. Because of this lack of data it is not possible to assess the risks.

4. In the absence of reliable data on the possible residual infectivity of the ash, it should be disposed of in controlled landfills.

5. Unburned material is commonly noted in the ash from small
incinerators.

6. The level of expertise available for the management of small incinerators is highly variable because few such facilities can afford to employ specialists in incineration.

The EC-SSC’s report concludes:

“In view of the uncertainty regarding the risks due to BSE/TSE contamination of the fly and bottom ash and airborne emissions it is recommended that further research is
conducted to identify the residual risks (along with attendant uncertainties) from the burial of ash (without further treatment,) in uncontained sites. It is essential that suitable monitoring methods are developed.”[17]

In a presentation to the Food and Drug Administration’s Transmissible Spongiform Encephalopathies Advisory Committee on July 17, 2003, Captain Edward Rau explained that “ash bed temperatures often may run 100°C lower than the actual air temperature” (in an incinerator’s burn chamber).[18] Captain Rau is an Environmental Health Officer with the National Institutes of Health and a co-researcher with Dr. Brown on the scrapie heat resistance study.

A 6,000 pound capacity incinerator burns nearly 3 million times the mass of the samples tested by Brown and Rau.  Many factors can affect an incinerator’s ability to completely
combust TSE contaminated waste material.  As Captain Rau explains:

“Probability of survival in ash not only depends on a lot of factors, the load density, the turbulence, the type of equipment, other operational factors.”

“Particularly, as things are just inserted into the incinerator, you tend to get a boil off of some of the material, a flash burn.  That can be carried over very quickly into the second chamber.”

“Reported temperatures for incinerators refer to the air. That is what is being monitored, and not the actual temperature in the ash.  Under abnormal conditions, a lot of things can really go wrong, cold start up conditions, overloading, inadequate control of the under fire air flow.” [19]

Overloading, excessive load density, inadequate air turbulence, and insufficient control of under fire airflow can all negatively impact incinerator performance.  Any of these conditions can result in incomplete heat penetration of the ash bed and insufficient residence time in the burn chamber.

Dr. David Taylor discusses this possibility in a paper on disposal issues related to TSE infected animals:

“Although incineration is generally regarded as the optimal method for the destruction of all microorganisms, there have been frequent reports of the discovery of organic material
in the resulting ash.  These findings indicate that the incineration process does not always perform according to the required standards.”[20]

Equipment breakdowns during burn cycles are likely to occur at some point.  These include electrical component failure, short circuits, and failure of fuel or air delivery systems. A common incinerator problem is refractory (firebrick) breakage.  If the burn chamber is not inspected and repaired on a regular basis, a damaged refractory can expose the steel wall of the burn chamber to high temperatures resulting in a “burn-through” and emergency shutdown.

Malfunctions can force a shutdown in mid-cycle.  The result is an unintended release of smoke from the stack since there is no way to effectively contain the combustion gases until the partially combusted waste material has cooled down. When an incinerator is in failure mode there is no way to close or contain the system to prevent release of infectious agents and other pollutants into the environment.

Operator training and supervision is crucial to incinerator performance.  Operators of hazardous waste incinerators are required by law to take classroom training courses and
annual refresher courses.[21]  The American Society of Mechanical Engineers has developed certification programs for hazardous and medical waste incinerator operators.[22] The Colorado Department of Public Health & Environment, however, does not require classroom courses, refresher training, or operator certification.

Incinerator upsets and problems may occur often, even in new facilities.  The Colorado Division of Wildlife (CDOW) operated two new pathological incinerators in the town of
Craig, Colorado during the 2002-2003 hunting season.  In daily logs obtained under the Colorado Open Records Act, the incinerator operator documented numerous problems and malfunctions.  Following are excerpts from the daily logs:

10-25-02  9:00 AM   8 hrs
First burn   Primary Temp. 1500°
Secondary Temp 1800°
57 Elk heads   47 Deer heads   104
Burn duration 8 hrs
9:30 A.M. – 5:30 P.M.   Cool down 2 hrs.
Cool down temp. 600° primary chamber.
was able to clean ashes out at this temp.
Produced about 40 gals of ash.
Stirred heads at 5 hrs. 6 hrs & 7 hrs during burn.
Only five heads were not completely incinerated.
Left them in with second burn.

10-25-02  2nd burn   10 hrs
8:15 P.M.   60 Elk   60 Deer   120
6:15 A.M. shut off
8:00 A.M. Temp was 700°
Load was not stirred during night.
App. 30 heads did not burn completely.
Some didn’t even have the hair cinched [sic].
We have been stacking heads in front of door.
Those don’t incinerate very well in this area,
was still some blood on floor in this area.

10-26-02 3rd Burn   8 hrs
9:00 A.M.   42 elk   68 Deer   112
Started pre-heating secondary chamber when loading primary.
Starting primary chamber when secondary is at 1200°-1300°
Increased primary to 1600°
Opened primary air blower to 8
Stirred heads every ½ hour after five hours of burning.

11-3-02   7th   10 hrs.
10:30 A.M   43 Elk   45 Deer   98 [sic]
#4 burner having trouble staying lit at start up

11-6-02   11th   10 hrs.
10:00 AM – 6:00 PM
66 Elk   40 Deer   106
starting to notice odor of burnt hair

11-7-02   12th   10 hr
9:45 AM – 7:45 PM
69 Elk   49 deer   118
Still odor
Secondary burning unit, paint is peeling & cracking around
large connection ring

11-12-02
Testing secondary chamber length of time to reach 1800° w/
primary chamber off.
12:45 A.M.   start  90°
1:15              1000°
1:45         1133°
1:55 1161°
2:45 1245°
3:30 1295°
4:30 1337°
5:50 1375°
shut off

11-13-02   15th   10 hrs
71 elk   46 Deer   12:15 A.M.   117
notice smoke around secondary burner when it ignited

11-14-02   16th   10 hrs
71 elk   7 Deer   78
9:15 A.M.   7:15 P.M.   Now winter fuel
50% #1 & 50% #2   won’t hold temp. in secondary

11-14-02
Frank Searles. Plant manager returned my calls this A.M.
Is sending a new thermocouple for secondary chamber.
Thinks the smoke might be from fuel being to [sic] cold.
Wants me to heat tape the fuel lines.
Also the area of smoke & paint peeling is not an air tight
seal in that area

11-16-02   18th   10 hrs
Elk 75   Deer 0   75
10:00 AM – 8:00 P.M.
Secondary chamber had to be reset
Did not fire

These records document several problems:

– Unburned heads and blood in burn chamber after 10 hour
burn
– Started burning load before secondary chamber reached 1800
degrees F
– Malfunctioning burner
– Noticeable odor of burnt hair
– Secondary chamber unable to reach 1800 degrees F
– Noticeable smoke
– Possible problem with cold fuel

In a May 2, 2002 report prepared for the Northern Larimer County Alliance, Duane Switzer interviewed Craig residents Ed and Pat Relaford regarding their experience living about 300 feet from the two incinerators.  The Relafords told Mr. Switzer:

– Bad smell.  Day and night when the incinerators are in operation.  Singed hair and burning flesh.

– Wispy smoke, that is to say, not billowing clouds.  In any case, the city attorney had told them there would be no smoke.

– Noise. The roar of the incinerators is constant and loud, to the point she could not sleep.

– The noise and smell are continuous day and night for 6 to 8 weeks straight.

The occupants of another house about 1,000 feet from the incinerators told Mr. Switzer they experienced a “foul smell” from the incinerators.[23]  In a July 15, 2003 article in the Craig Daily Press, Ed Relaford confirmed that the stench of burning flesh permeated his neighborhood.[24]

Alkaline Tissue Digestion and CWD

Alkaline tissue digestion is the only proven technology for prion inactivation that is capable of handling large volumes of animal carcasses.  It is based on the process of alkaline hydrolysis, which is the breaking of chemical bonds by the insertion of water between atoms, catalyzed by alkali metal hydroxides.

The technology for hydrolyzing large quantities of animal carcasses was developed in 1992 by Dr. Gordon Kaye and Dr. Peter Weber, professors at Albany Medical College in New York.  The equipment consists of an insulated, steam-jacketed, stainless steel pressure vessel with a lid. Carcasses (or heads) are loaded into a basket that is placed
inside the vessel.  The load is automatically weighed, and the appropriate amounts of water and alkali are automatically added.[25]

The vessel is sealed and the contents are heated by steam. The alkali solution is continuously recirculated and agitated.  There are no moving parts inside the vessel. The
tissues are dissolved and are hydrolyzed into smaller and smaller molecules.[26]  The recommended digestion cycle time is six hours based on experiments done by Robert Somerville in 2002, funded by the UK Department of the Environment, Food, and Rural Affairs (DEFRA).[27]

The Somerville experiments involved digestion of sheep heads inoculated with mouse-passaged BSE agent.  Different chemical and time parameters were tested.  Samples of the resulting hydrolysate were diluted and injected into mice. Although infectivity remained after 3-hour digestion cycles, no infectivity was detectable after a 6-hour cycle.[28]

Due to constraints specific to the Somerville experiments, the European Commission Scientific Steering Committee (EC-SSC) concluded in its April 2003 opinion that further
studies are needed “before any final assurance could be given regarding the safety of the process with respect to TSE risks”.[29]

It should be noted that the precautionary approach to digestion by the EC-SSC has never been applied to the process of incineration.  This is perhaps because of the widely held, though not scientifically proven, assumption that incineration is an effective means of inactivating TSEs.  Regardless, with respect to TSE inactivation, alkaline tissue digestion has been subjected to far greater scrutiny than incineration.

Responding to an early version of the EC-SSC’s opinion, Dr. David Taylor prepared a risk assessment of alkaline digestion assuming a digester with the capacity to process ten BSE-infected bovine carcasses.  Dr. Taylor concluded that “a human would have to consume at least 126,000 litres (over 33,000 gallons) of effluent from the production
process to have a 50% chance of developing variant CJD.”[30]

Further reinforcing the effectiveness of alkaline hydrolysis are Dr. Taylor’s comments in his 2000 review of prion inactivation methods:

“The only methods that appear to be completely effective under worst-case conditions are strong sodium hypochlorite solutions or hot solutions of sodium hydroxide.”[31]

Apparently convinced that alkaline tissue digestion is effective, the European Commission is in the process of adopting the final language of regulations approving
alkaline hydrolysis for disposal of TSE-infected materials.[32,33]

Compared to incinerators, alkaline digesters are safer particularly in the failure mode because the system is self-contained.  In the event of loss of temperature and pressure, or mechanical breakdown, the contents remain inside the sealed vessel until repairs are completed and the process is restarted.

The effluent from a digester can either be dehydrated and the remaining solids landfilled, or an anaerobic digestion process can be utilized.  Many facilities reduce the pH
level of the effluent and release it into municipal sewer systems with no adverse effects.

Alkaline tissue digesters have already become the waste disposal technology of choice at a variety of installations. Health Canada’s Host Genetics and Prion Diseases Federal
Laboratories in Winnipeg took delivery of a small digester in January 2000.  In April of that year, the US Department of Agriculture’s (USDA) Animal Research Service lab in
Laramie, Wyoming installed a 1,500-pound capacity tissue digester.  In February 2001, the USDA’s Animal and Plant Health Inspection Service in Ames, Iowa purchased a 7,000-pound digester to dispose of 350 sheep exposed to an unidentified prion disease.[34,35]

Colorado State University’s Veterinary Diagnostic Lab (CSU-VDL) in Fort Collins installed a 2,000-pound digester in October 2001.  The facility is a joint venture of CSU,
the Colorado Department of Agriculture, and the USDA. During the 2002-2003 hunting season, the DOW contracted with the CSU-VDL to dispose of 140,189 pounds of deer and elk heads and carcasses, many infected with CWD.[36]

The College of Veterinary Medicine at the University of Pennsylvania purchased a 7,000-pound unit last year specifically for prion destruction.[37]  In a joint venture, the USDA, the Wisconsin Veterinary Diagnostic Laboratory (WVDL), and the Wisconsin Department of Agriculture, Trade and Consumer Protection are deploying a mobile tissue digester to be available for state use in dealing with the CWD “emergency” as well as other animal disease outbreaks. The USDA has provided $1 million for the purchase of the digester as part of a homeland security grant to the state and WVDL.[38]

The Cornell College of Veterinary Medicine (CCVM) in Ithaca, New York is finalizing funding for an alkaline tissue digester to replace its 18-year-old pathological incinerator.  In the Draft Environmental Impact Statement for the project, the CCVM concludes the following significant positive impacts on human health are to be expected:

“The significant reduction in air pollutants and greenhouse gases (e.g., NOx and CO2) would result in a positive impact on human health.”

“Moreover, the Proposed Action would provide more reliable treatment of animal remains infected with prions, the causative agents of Mad Cow Disease and other
Transmissible Spongiform Encephalopathies (TSEs) compared with current treatment (i.e., incineration) based on research published to date, and would protect public health
to the maximum extent in the event that prion-infected wastes were received by the CCVM.”[39]

Compared to incineration, alkaline tissue digestion is a more reliable method of TSE inactivation, has undergone more scientific scrutiny, can be contained in failure mode,
is simpler to operate, is a less complex technology, and costs less to operate per pound of waste.

Alzheimers disease epidemic

Cross-Species Transmission of TSEs

The Raymond et al. 2000 in-vitro study found that the human molecular barrier to CWD is approximately as effective as the human molecular barrier to BSE.[40]  While the
transmission of BSE to humans is inefficient, it has certainly proven to be possible.  U.K Department of Health statistics as of February 2, 2004 indicate that 139 people have died of definite or probable variant Creutzfeldt-Jakob Disease (vCJD).[41]  It is believed that variant CJD is caused by consumption of beef contaminated with BSE.

The study shows that, at the molecular level, humans are no less susceptible to CWD than to BSE.  The study’s authors conclude “since humans have apparently been infected by BSE, it would seem prudent to take reasonable measures to limit exposure of humans (as well as sheep and cattle) to CWD infectivity”.[42]

Many of the 692 cases of sporadic Creutzfeldt-Jakob Disease recorded in the U.K. since 1990 may also be linked to BSE. Sporadic CJD has been thought to occur spontaneously and not as a result of exposure to a pathogen.  This theory was called into question in a 2002 study by Emmanuel Asante, John Collinge, and others showing that BSE could produce a disease indistinguishable from sporadic CJD.  The authors conclude, “some patients with a phenotype consistent with sporadic CJD may have a disease arising from BSE exposure.” [43]

Any natural or molecular barriers humans may have against CWD may be overcome by the agent’s potential for adaptation. In a study by scientists at the Rocky Mountain Laboratories in Hamilton, Montana, a strain of hamster scrapie gradually adapted to cause illness in mice that were previously not susceptible to the disease.

The research revealed that scrapie prions could persist in asymptomatic mice for years at levels too low for standard lab tests to detect.  When the agent was transferred from
the original group of mice to additional groups, the disease grew stronger making the newly infected mice sick. Researcher Richard Race explained: “The scrapie seemed to have learned how to deal with this new species, and it worked much better.  It replicated faster in additional rounds of mice and even became more lethal to them.”

Race noted the study “confirmed that prion disease can adapt to new species”, and that “the process is slow and difficult to detect”.  Applying his results to CWD, Race said: “If BSE were derived from sheep scrapie, then adaptation during passage in cattle may have increased its pathogenicity for humans.  A similar situation could occur with CWD.  CWD transmission to other cervids or livestock could change its characteristics, including its potential for transmission to people.”[44]

In a similar study conducted in the U.K. on subclinical prion infection, results led the researchers to caution that “current definitions of the species barrier, which have been
based on clinical end-points, need to be fundamentally reassessed”.[45]

Noted CWD researcher Dr. Elizabeth Williams from Laramie, Wyoming had the following to say about the risk to humans:

“I do think it is legitimate to be concerned about the potential for humans being susceptible to CWD.  We don’t have evidence…but we can’t say it could never happen and
we have to be prudent.”

mad cow disease and prions

CWD Transmission To Cattle

Regarding CWD transmission to cattle, the results are mixed. In an ongoing study in Wyoming, cattle fed brain tissue from CWD-infected mule deer have not gotten sick after 6 years. A study in Ames, Iowa has yielded different results.  In 1997, 10 calves were inoculated intracerebrally with the same inoculum used in the Wyoming experiment.  As of mid-2003, 5 calves had developed CWD.

Although the Wyoming study involves a more natural route, ingestion may simply result in a more prolonged incubation period.  Alternatively, based on the work done by Race, et al. on TSE adaptation and species barriers, the test cattle in Wyoming may be asymptomatic carriers harboring a gradually adapting CWD agent.

Complicating matters, a recent study analyzing “glycoform” patterns of abnormal prion protein from CWD-affected deer and elk, scrapie-affected sheep and cattle, and BSE-affected cattle failed to identify patterns capable of reliably distinguishing these TSEs.  Difficulty in identifying the source of a TSE following cross-species transmission adds to
the uncertainty surrounding CWD and possible risks to cattle and humans.  The authors write: “Sheep scrapie has been present in the United States since at least 1947, and in many geographical areas, sheep, deer, and elk share pastures and rangeland.  If scrapie-affected sheep were present in these situations, then cross-species transmission might have occurred.  Sheep scrapie is not thought to cause disease in humans, although passage through cattle appears to have changed this characteristic.  It remains to be determined if the same will be true of CWD.”

The European Commission’s Scientific Steering Committee (EC-SSC) released a lengthy, comprehensive report and opinion on CWD in March 2003.  Cross-species transmissibility experiments and risks are discussed in detail.  The EC-SSC report reviews the successful transmission of CWD by intracerebral inoculation to ferrets, mice, a squirrel monkey, mink, a goat, and a sheep.  The report concludes, “…it remains theoretically possible that the CWD-agent could infect humans.

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Crossbow Communications specializes in issue management and public affairs. Alzheimer’s disease, Creutzfeldt-Jakob disease, chronic wasting disease and the prion disease epidemic is an area special expertise. Please contact Gary Chandler to join our coalition for reform gary@crossbow1.com.