DISTRIBUTION OF AIRBORNE MOUSE ALLERGEN IN A MAJOR MOUSE BREEDING FACILITY

Background: Occupational allergy to mice is a major cause of disabilit y among workers in mouse breeding and research facilities. Efforts to prevent and treat allergy require a detailed knowledge of exposure lev els to allergen. Objective: This study was designed to quantitate the level of major mouse allergen (Mus m I) in central room air and immedi ate breathing zones under a variety of working conditions. Methods: An Andersen sampler (Groseby Andersen, Spirotech Div., Atlanta, Ga.) was used to collect allergen in each room. A Gillian Personal sampler (Gi llian Instrument Corp., West Caldwell, N.J.) collected particles in th e worker breathing zone. ELISA was used to quantitate the concentratio n of Mus m I collected on the two collection devices. Results: Total M us m I recovered from Andersen samplers ranged from 0.2 to 1.5 ng/m(3) irt rooms without mice and 0.5 to 15.1 ng/m(3) in rooms with mice. Al lergen recovered from the zone of worker activity ranged from 1.2 to 2 .7 ng/m(3) in rooms without mice and from 16.6 to 563.0 ng/m(3) in roo ms with mice. Direct mouse contact was associated with the highest lev esl of exposure to Mus m I. Analysis revealed the bulk of allergen to be in mid-particle size ranges (3.3 to 10 mu m) for mouse-containing r ooms and in small particle size range (0.43 to 3.3 mu m) for non-mouse -containing rooms, suggesting that small particles were carried along corridors from rooms with mice into non-mouse-containing rooms. Ventil ation characteristics of rooms and mouse population density were evalu ated with a ''mouse loading'' index (number of mice per cubic meter of ventilated air per hour). Mouse loading correlated strongly with smal l particles (<3.3 mu m) in ambient air. Conclusions: Mus m I is widely distributed within mouse breeding facilities. Direct worker contact w ith mice seems to be the major factor in high level exposure.