Worldwide distribution
Exposure to laboratory animal allergens is a significant cause of IgE-mediated occupational allergy and asthma in the pharmaceutical sector, contract toxicology laboratories, research institutes and universities (2); reported prevalence rates range from 11% and 30% (4).
In a study of 101 laboratory animal technicians, 30% had symptoms (100% had rhinitis; 10% had concurrent bronchial asthma), and 19% had confirmed allergy (4). In the same study, 18% of laboratory workers exposed to rats, had confirmed allergy (4). All the rat-sensitized individuals had been working with mature male animals (4).
In a study of occupational sensitization to rat and/or mouse urinary allergens, out of 498 employees exposed to both rat and mouse at work and 220 exposed to rat only (6), 14% were sensitized to rats.
Risk factors
Exposure to rat urine in the workplace, especially research laboratories (2), or in the home (1).
Some handling and husbandry activities are associated with high exposures (2). For example, filtered cages may reduce exposure, while filter changing and/or cleaning can lead to high exposures (2). Equally, continued contact with animals may raise sensitivity; mild symptoms may serve as a precursor to a warning for the risk of developing bronchial symptoms (4).
A history of atopic disease; in one study, atopy was overrepresented in technicians with positive RAST and skin test reactions to the animal allergens compared with technicians without positive tests (4).
