Appendix 2 - Sanitary Precautions/Disinfectants

Scrapie is not considered to be a human pathogen. Safe work practices are outlined in Section 1.6 of the Common Procedures Manual - Personal Safety Practices. With large scale operations, one individual should be assigned, amongst other duties, the role of a safety officer to assure that workers adhere to safe work practices.

Wear protective clothing, gloves and face protection when collecting brain specimens. Always avoid direct contact with brain tissues. Personnel at tissue harvesting sites should take precautions to avoid ingestion of the agent.

It is recommended that a disposable plastic drop sheet be used on which to place the animal's head. The sheet should be large enough to cover the work area.

1. Chemical decontamination of equipment and work surfaces with sodium hypochlorite (NaOCl) at a concentration of 2% available chlorine, or sodium hydroxide (NaOH) at a concentration of 2 Molars, is recommended. Surfaces and equipment should be left wet (or soaking) with NaOCl or NaOH for at least one hour at 20°C. Alternatively, a 5% concentration of phenol disinfectant DIN 02258943 (Environ LpH or Canadian LpH) has been documented to decontaminate metal contaminated with TSE agents when used for 30 minutes at 20°C and may be used on washable, hard, non-porous surfaces (such as floors, tables, equipment, and counters), items (such as non-disposable instruments, sharps, and sharp containers), and/or laboratory waste solutions (such as formalin or other liquids).

2. Sodium hypochlorite (NaOCl) can be prepared from industrial grade or commercially available bleach (such as Javex). Dilute the bleach to provide a final concentration of 2% (20 000 ppm) available chlorine. For example, most commercially available bleaches have 6% available chlorine listed on the label. In this case, mix one part bleach and two parts water (ratio 1:2) to attain the 2% concentration of available chlorine.

3. NaOH can be purchased from Fisher Scientific in crystal form. To make a 2 Molar concentration of NaOH, dilute 80 grams NaOH crystals in one litre of water and stir well.

It is recommended that neurosurgical tools be soaked in NaOH for one hour, removed from the solution, and wiped with the NaOCl solution for 10 seconds. Dry the tools as the NaOCl is corrosive.

4. Apply a 5–9% concentration of the Environ LpH diluted in water (7–12 ounces of product to 1 gallon of water) to washable, hard, non-porous surfaces or items by mop, cloth, sponge, brush, squirt bottle, low volume coarse spray applicator, or immersion and maintain contact for at least 30 minutes. Re-treat as necessary to keep wet throughout the 30-minute time period. Following the contact time, surfaces or items may be rinsed with water and allowed to air dry. Items may also be soaked in a 0.9% concentration of the product (1.5 oz of product per gallon of water) for at least 16 hours. For laboratory waste solutions, add Environ LpH to create a final concentration of 5–9% and allow a treatment period of at least 30 minutes or add Environ LpH to create a final concentration of 0.9% and allow a treatment period of at least 16 hours.

Note: Other traditional disinfectants such as VIRKON are NOT effective against prion agents. Disinfection of instruments must be done with either sodium hypochlorite, sodium hydroxide or Environ LpH.

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