Objectives: The purpose of this study was to determine exposure levels in the laboratory during different tasks and evaluate the effectiveness of safety equipment used to reduce personal exposure.
Methods: Personal and stationary air samples were collected during different tasks in a laboratory animal facility in which several allergen reduction strategies had been implemented. Mouse urinary allergen concentrations were measured using a polyclonal sandwich enzyme-linked immunosorbent assay. Sera from the personnel (n = 29) were analysed every 6 months for the presence of specific antibodies against mouse and rat urinary allergens, and the staff answered questionnaires on work-related symptoms, exposure and use of respiratory protection.
Results: The highest airborne mouse allergen levels were measured during manual emptying of cages, during changing of cages on an unventilated table and during handling of male animals on an unventilated table. Automatic emptying and cleaning of cages resulted in low airborne allergen levels in the working room. Using a ventilated cage-changing wagon reduced the allergen exposure level from 77 to 17 ng/m3. The housing of animals in ventilated cabinets, with air exhausted through the cabinet, effectively prevented the release of allergens into the ambient air. The handling of animals on ventilated benches and the use of a centralized vacuum cleaner resulted in a low exposure level. Only two subjects developed specific immunoglobulin E of > 0.35 kU/l, of whom one was reduced to negative after increased use of respiratory protection.
Conclusions: Effective reduction of exposure to allergens can be achieved by several strategies, which together appear to minimize sensitization to rodents.