Controlling Allergen Exposures

Laboratory animal allergies can pose a serious health concern for those who work with or near animals. Vertebrate animal allergens are proteins found in animal urine, saliva, fur, feathers, dander, and feces. Exposure to allergens can occur if you inhale them, if they contact your skin or eyes, or if they enter your body through breaks in the skin such as bites. Inhalation is one of the most potent routes of exposure. Allergens can be released into the air when dander or fur is shed from animals and when materials containing allergens are disturbed. Tasks that may generate airborne exposures to allergens include cage changing, cage dumping and washing, and performing procedures on animals or animal tissue. You do not have to work directly with animals to be exposed to their allergens. If allergens are released into the air, anyone in the room can be exposed. These laboratory animal substances are particularly potent allergens: mouse or rat urine, cat saliva, rabbit fur, dander from dogs, cats, ferrets, guinea pigs, and hamsters.

Exposure to allergens during work with laboratory animals can result in allergic reactions. Symptoms may include sneezing, itchy eyes, skin rashes, and in severe cases, asthma, or anaphylaxis. Prevention of symptomatic allergic reactions and disease progression is most effectively accomplished through reducing exposure at the source. 

Risks to personnel associated with laboratory animal allergen (LAA) exposure can be mitigated by applying intervention strategies and controls which limit direct exposure to allergens. Implementation of control measures should prioritize those measures which effectively remove the hazard from the workplace rather than relying on personnel to reduce their own exposure through behavioral strategies and/or the use of personal protective equipment (PPE).

When research goals can be achieved without the use of live vertebrate animals, the LAA exposure risks are effectively eliminated. Researchers should consider the use of in vitro, in silico, or computer modeling/simulation when it is possible to achieve research goals in this manner. As allergen production and sensitization vary depending on the animal species and/or sex consideration in selection of the model system may provide an opportunity for substitution of less allergenic model provided it meets the research goals. For example, research completed in a zebrafish model system would present less LAA exposure risk than a study completed in a rodent model system.

Engineering controls and facility design elements effectively alter the work environment to reduce exposure-related hazards. These types of controls are preferred over all others because they reduce exposure to hazards and do not rely entirely on worker behavior. By reducing a hazard in the workplace, engineering controls can be the most effective exposure control method. 

Engineering controls include, but are not limited to: 

• Animal transfer stations 
• Biological safety cabinets (BSCs)
• Chemical fume hoods 
• Local exhaust ventilation, including exhaust snorkels
• Downdraft Tables
• Cages with filter tops or cage racks that filter the air before releasing it into the room 

Appropriate exposure control devices should be utilized for all operations with high potential for allergen exposure. These include but are not limited to handling animals, cage changing, and dumping soiled bedding. Ensure that you are utilizing the appropriate exposure control device for your operations and that you have been trained to utilize the equipment, https://uky.scishield.com/raft/training/courses. Use of a laminar flow bench that directs airflow toward the user’s breathing zone should be avoided.

Facility design elements provide building ventilation systems that minimize recirculation of air, control directionality of air, and provide adequate air changes to effectively mitigate exposure to allergens and other hazards in animal research facilities. Handwashing sinks, eyewashes/safety showers, and cage washing and sanitation facilities are additional design elements which support allergen exposure control.

Facilities housing laboratory animals should maintain adequate humidity, temperature, and ventilation (air changes) and provide directional airflow from less potentially contaminated areas to areas of higher exposure potential. Ventilation is provided in accordance with the Guide for the Care and Use of Laboratory Animals (Guide), NRC 2011. A standard recommendation for room ventilation rates is 10 to 15 air changes per hour (ACH). Ventilation rates may be increased or decreased based upon housing density, caging type, operations, and hazards in use.

Animal research activities that cannot be conducted with appropriate engineering controls or are in facilities without adequate ventilation should be reviewed and assessed by Environmental Health and Safety. To request a review or consultation of animal research activities, send an inquiry to labsafety@uky.edu. 

Work practices are procedures for safe and proper work that are used to reduce the duration, frequency, or intensity of exposure to a hazard. These controls need to be understood and followed by all personnel with potential exposure to LAAs. 

• Access to the animal room is limited. Only those personnel required for experimental, husbandry, or support purposes are authorized to enter the facility.
• Personnel entering animal facilities are covered by an occupational medical program.
• Post signage to communicate the presence of laboratory animals.
• Minimize aerosolization and cross contamination in all tasks. Work slowly and carefully.
• Utilize appropriate restraint methods, chemical and/or physical, to reduce the risk of bites, scratches, and needlestick injuries.
• Use of needles and syringes or other sharp instruments is limited in the animal facility and is restricted to situations where there is no alternative (e.g., parenteral injection, blood collection, or aspiration of fluids from laboratory animals or diaphragm bottles). Active or passive needle-based safety devices are used whenever possible.
• Eating, drinking, smoking, handling contact lenses, applying cosmetics, and storing food for human consumption are not permitted in animal areas.
• Gloves are worn when handling animals to protect hands from exposure to hazardous materials and allergens. 
  • Gloves worn inside the animal facility are not worn outside the animal facility.
  • Gloves are changed when contaminated or when glove integrity is compromised.
  • Disposable gloves and other disposable PPE are not washed or reused. 
  • Gloves and other PPE are removed in a manner that minimizes personal contamination.
• Personnel wash their hands after handling animals and before leaving the areas where animals are housed or manipulated.
• Work surfaces are decontaminated after completion of work.
  • Utilize wet wiping and mopping.
  • Vacuuming, when necessary, should employ HEPA filtration.
• Do not launder lab coats and other reusable protective clothing at home.
• Do not handle open cages outside of engineering controls. 
• Ensure filters are in place when using filter-top microisolator cages.
• Use solid bedding rather than loose bedding in operant boxes, metabolic cages, or other open-style housing.
• Utilize wet methods and exposure control devices for animal shaving and hair removal procedures.
• Report signs and symptoms of animal allergies or related conditions through the Animal Handler Occupational Health Program.

Personal Protective Equipment (PPE) is protective gear needed to keep workers safe while performing their jobs. While engineering and administrative controls and proper work practices are more effective in minimizing exposure to many workplace hazards, the appropriate use of PPE further reduces exposure to LAAs.

• Use PPE to reduce skin and eye exposure.
• Respiratory protection may be required in areas where other exposure control measures are not adequate (engineering control devices unavailable, limited facility ventilation). Use of respiratory protection follows UK Respiratory Protection Program, https://ohs.uky.edu/industrial-hygiene/respiratory-protection.
• Laboratory coats, gowns, or uniforms are the minimum recommended to prevent contamination of personal clothing. 
  • Protective outer clothing is not worn outside areas where animals are housed or manipulated. Do not wear the same reusable PPE in the animal facility and the laboratory. 
  • Dedicate a lab coat/gown and other required PPE for animal use and transport between locations in a contained manner. 
  • This can be accomplished by utilizing a sealable bag or placing it inside a closed animal transport cart.
• Eye protection and face protection (e.g., safety glasses, goggles, mask, face shield, or other splatter guard) are used for manipulations or activities that may result in exposure to the eyes or mucus membranes. 
  • Eye protection and face protection are disposed of with other contaminated facility waste or are decontaminated after use.

Practicing good hand hygiene (handwashing) is one of the most important LAA exposure reduction strategies. When working in animal facilities and research laboratory environments, be aware of the location of the nearest handwashing sink and verify that there are soap and paper towels present. Wash hands after removal of gloves, upon leaving the facility, and/or before eating/drinking or using restroom facilities. Utilize waterless hand sanitizer when handwashing facilities cannot be immediately accessed and wash hands with soap and water when available. Additional information available at https://researchsafety.uky.edu/general-lab-safety/hand-hygiene.