Environmental Health & Safety

University of Colorado Boulder


Animal Allergens in Animal Research Settings: Understand the Risks

This Environmental Health & Safety guideline documentation is intended for researchers and laboratory personnel.

Revised as of October 21, 2014

Allergic reactions to animals are among the most common conditions the affect the health of animal researchers and staff. Per Lutsky (1987), 75% of all institutions with laboratory animals had animal-care workers with allergic symptoms. In the population of regularly exposed animal researchers and staff, the prevalence of allergic symptoms ranges from 10% to 44%. Approximately 10% of laboratory workers eventually develop occupation-related asthma. Up to 73% of persons with pre-existing allergic conditions will develop allergies to laboratory animals. Worsening allergic conditions evolve over time, generally over the course of 1-2 years, but may vary. Of the 73% with laboratory animal allergies, approximately 10% of these will develop chronic asthma, even if they no longer work with animals.

Table: Allergic Reactions to Laboratory-Animal Allergens

Diagnosis Symptoms Signs
Contact urticarial Redness, itchy skin, welts, hives Raised, clearly demarcated red lesions
Allergic conjunctivitis Itchy, tearing, red eyes; swollen conjunctiva; often accompanied with allergic rhinitis symptoms Conjunctival vascular engorgement,  clear discharge (usually bilateral eyes)
Allergic rhinitis Sneezing, itchiness, clear nasal drainage, nasal congestion Pale or edematous nasal mucosa, clear rhinorrhea
Asthma Cough, wheezing, chest tightness, shortness of breath Decreased breath sounds, prolonged expiratory wheeze, reversible airflow obstruction with use of bronchodilator, airway hyper-responsiveness
Anaphylaxis Generalized itching, hives, throat tightness, eye or lip swelling, difficulty in swallowing, hoarseness, shortness of breath, dizziness, fainting, nausea, vomiting, abdominal cramps, diarrhea Flushing, urticarial, angioedema, stridor, wheezing, hypotension

Most of the symptoms above begin within 10-15 minutes of exposure to allergens.  However, some reactions can occur immediately and may also have a later component.  The later component symptoms can recur 4-6 hours post-exposure without further antigen stimulation.

Generally, the risk for developing allergic symptoms is related to the duration of exposure to the animal allergens and to the concentrations of allergens for specific tasks.  Cage-cleaning puts animal staff at most risk for developing animal allergies.  For researchers and staff who have asthma, working in a vivarium containing an animal to which they have become sensitized, can cause a 10% decrease in their pulmonary function.

Mammal allergens can cause routine allergic and severe allergic responses.  Birds can cause the same allergic responses but are also a source of hypersensitivity pneumonitis.  This condition mimics a pneumonia-like illness and can occur up to several hours after exposure.  Symptoms may include fever, cough, chills, myalgias (body aches), and shortness of breath.

Pre-placement screening is important to help identify and alert researchers and staff who might be at increased risk for developing laboratory animal allergies and/or asthma.  It is important to identify these individuals so they may be appropriately educated about taking preventive measures.  The presence of allergies and/or asthma should not preclude employment or research lab choice.

People who are routinely exposed to animals, including fish and reptiles, should undergo initial and annual allergy screening to detect those who are developing allergy symptoms so that appropriate interventions can be taken to prevent long-term chronic illnesses.

Facility design can be helpful in reducing the incidence of animal allergies.  The use of HEPA filters and humidifiers can reduce certain animal allergens.  The choice of ventilated cages and bedding can also greatly influence the amount of airborne allergens.

Education about individual risks is also key to controlling allergy symptoms.  Individuals with a history of allergies and known sensitivities to animals are at high risk for developing laboratory animal allergies.  The use of PPE may reduce the likelihood of symptoms.  Minimizing exposure times in animal facilities may also help at-risk individuals.  People who develop or are developing allergic symptoms will be recommended for further evaluation by either the institutions’ workers’ compensation provider or their own health care provider if they do not qualify for workers’ compensation.