Control strategies for aeroallergens in an animal facility

Background: Prevalence of the occupational disease laboratory animal allerg y could be reduced if aeroallergen reduction strategies are identified, Objective: To reduce worker exposure to Mus m 1, an allergen from laborator y mice, the effect of filter cage tops, increased room ventilation, negativ ely pressurized ventilated cages, and ventilated cage-changing tables were evaluated. Methods: Aeroallergen was collected in the ambient air and in the breathing zone and quantified by using a competitive immunoassay. Results: When mice were housed in unventilated cages, ambient allergen was reduced from 5.1 ng/m(3) with no cage top to 13 ng/m(3) with a simple filte r-sheet top and 0.8 ng/m(3) with a fitted filter-bonnet top (P < .05), Room ventilation was increased from 6 to 10, 15, and 20 air changes per hour an d had little effect on aeroallergen levels and no impact on airborne partic ulate matter. When mice were housed in ventilated cages, ambient allergen w as significantly reduced from 1.1 ng/m(3) at positive cage pressure to 0.3 ng/m(3) at negative cage pressure (P < .05), Negative cage pressure combine d with handling animals under a ventilated table reduced breathing zone all ergen from 28 ng/m(3) with neither control strategy in place to 9 ng/m(3) ( P < .05). Use of a ventilated table controlled bacterial contamination, mea sured as colony forming units, found in negatively pressurized cages. Conclusion: Three aeroallergen control strategies are use of filter cage to ps, operation of negatively pressurized cages, and use of ventilated changi ng tables.