Spring 2011

Laboratory Animal Allergens (LAA): Are you at risk?

traingleAllergic reactions are among the most common conditions affecting the health of workers involved in the care and use of research animals. Between 11 and 44% of the individuals working with laboratory animals report work-related allergic symptoms. Of those who become symptomatic, 4 to 22% may eventually develop occupational asthma that can persist even after exposure ceases (Bush and Stave 2001).  Sensitivity can occur in workers after many months of exposure or after many years of exposure, depending on individual susceptibility, and possibly affecting individuals differently.  The best way to avoid developing animal related allergies is to know the risks and take preventative measures to reduce your exposures. 

What Causes an Animal Allergy?
LAA is triggered by protein allergens found in the urine, dander, hair or fur, and saliva of animals.  Allergens can also present in bedding, on cages, and other work surfaces.

The most common causes of laboratory animal allergies are rats and mice, primarily because these animals are used more often.  Other animals which are known to have a high risk of causing animal allergies include guinea pigs, rabbits, hamsters, cats, dogs, and monkeys.

How can Employees be Exposed?
The primary route of exposure to animal allergens occurs predominantly through the inhalation of airborne allergens.  Direct skin contact and eye contact can also be a common route.  Percutaneous exposures may result from animal bites, needle punctures contaminated with animal allergens, or allergen contaminated wounds.

The highest exposure levels occur when handling live animals and their bedding.  Activities that have the highest exposures include; cage dumping, cage changing, feeding, animal care, using cages without filter tops, high density cages, and using non-absorbent bedding.  High exposure may also occur while performing procedures on or manipulating the animals.   You can lower the risk for laboratory animal allergies by decreasing airborne level and minimizing direct exposure.

What are the Symptoms of Animal Allergies?
The most common symptoms are nasal congestion and runny nose.  They are also often manifested by itchy eyes, rashes, and asthma. Other symptoms may include sneezing, coughing, chest tightness, and shortness of breath.

How can You Prevent Exposures to Animal Allergens?
Methods to prevent exposures include: engineering controls, administrative controls, work practices, housekeeping, and personal protective equipment (PPE).

Engineering Controls
Engineering controls are recognized as the most effective method for controlling occupational exposure to potential hazards.  The best method is a local exhaust ventilation system located near the animal housing or bedding that carries airborne contaminants away from the employee’s breathing zone.  Examples include; Biological safety cabinets, fume hoods, and downdraft tables.  Vented dumping stations are highly recommended for cage dumping. Contact bedding should be highly absorptive, contaminant free, and dust free.   When feasible, use individually ventilated animal racks and microisolator (filter top cage) cages to provide protection for the animals and to minimize the potential for employee exposure to animal allergens.

Administrative Controls
The movement of animals should be minimized whenever possible.  When transporting animals employees should follow these recommended work practices: 

  • Avoid moving animals into the laboratory unless it is not feasible for the procedures to be performed in the animal facility;
  • If transportation is necessary, it is recommended that the animals be in a microisolator (filter top cage), an approved filtered transport ventilated rack, or at a minimum the cage/caging system be covered; 
  • When movement of animals is necessary, it is recommended that the animals be transferred to clean cages before moving them to the laboratory; and
  • It is recommended that animals be maintained and manipulated on or in a local exhaust system in the laboratory such as a biological safety cabinet, fume hood, or downdraft table. In areas, where local exhaust systems are not feasible, appropriate PPE consisting of an N95 respirator, disposable gown, and disposable latex or nitrile gloves is recommended.

Work Practices
Animal facilities or laboratories housing animals should be cleaned on a regular schedule using wet methods.  Dry sweeping is not the preferred method for cleaning animal rooms.  Employees should follow these recommended work practices:

  • Clean work surfaces routinely to reduce allergen loads;
  • Avoid dry sweeping when possible.  Use a HEPA vacuum if needed; 
  • Promptly bag and correctly dispose of waste materials in the appropriate receptacle(s);
  • Dispose of shipment /transfer boxes promptly. These boxes should not be left out in the open corridors or in laboratories for a period of more than 8 hours;
  • Cover dirty caging and equipment while transporting through hallways and to the cage wash area;                                                                              
  • Leave dirty PPE in the animal room and/or laboratory to keep from contaminating the hallways with allergens; and
  • Shave animals in a fume hood or biological safety cabinet, if possible. 

Employees shall take responsibility for maintaining adequate personal hygiene while working with animals.  Employees should follow these recommended practices:

  • Eating or drinking is not permitted in animal rooms or laboratories;
  • Employees are discouraged from touching their face and eyes while in animal rooms and laboratories;
  • Remove PPE and wash hands before leaving an animal facility;
  • Animal Facility Employees wear uniforms or scrubs instead of street clothes.  It is recommended that employees change back into street clothes before leaving the facility to avoid potential exposure to family members;
  • Wash hands with soap and water frequently. Wash hands and face before leaving the work area and before eating or drinking; and
  • Reduce skin contact with animal products such as dander, serum, and urine.

 Personal Protective Equipment (PPE)
Personal protective equipment should be used in conjunction with engineering and administrative controls to reduce skin contact and inhalation of animal allergens to reduce employee exposures.

It is recommended for employees working with animals and/or soiled bedding at a minimum wear disposable latex or nitrile gloves and disposable or facility maintained cloth isolation gowns or lab coats.

Additional PPE such as hair bonnets are also recommended to limit the spread of animal allergens beyond the animal facility and further limit personal exposure.   PPE should not be worn outside the laboratory.traingle

In circumstances were local exhaust ventilation is not available N95 respirators are recommended. The use of N95 respirators is recommended for employees handling animals outside of the Animal Facilities or where local exhaust ventilation is not available.  N95 respirators are also recommended for employees handling soiled bedding.

Before wearing an N95 respirator employees must complete a medical questionnaire located at http://www.ehs.iupui.edu/ehs/indus_hyg_respiratorQuestionnaire.asp , complete online training, and be fit tested by EHS.

What if You Develop Symptoms?
Allergies to laboratory animals are considered an occupational illness.  If you are experiencing allergy-type symptoms you should report them to your supervisor for further evaluation and investigation.  Employees with signs and symptoms of an animal allergy are recommended to complete an injury/illness form, and report to IUPUI Health Services, 274-5887, for medical evaluation and treatment.