Airborne exposure to laboratory animal allergens

Exposure to laboratory animal allergens remains a significant cause of IgE-mediated occupational allergy and asthma. Since 2005, we have measured the major mouse and rat allergens (mus m 1 and rat n 1) collected on filters from air sampling in a range of UK and non-UK animal facilities. Supplied core data allowed us to construct an anonymized database of atmospheric results in ng m^–3 containing 3080 mouse and 1392 rat analyses. Roughly twice as many static samples compared to personal samples had been sent for analysis. The medians (90^thpercentiles) for the mouse and rat allergens employing personal atmospheric sampling were 2.6 (60.6) and 0.4 (12.4) ng m^–3 respectively; for static samples the equivalent values were 0.2 (3.7) and 0.1 (1.4) ng m^–3. Where unequivocal sample descriptors were provided with samples, results were categorised to activities/areas. Medians and 90^th percentiles in these categories suggest that staff undertaking cleaning out, dumping of soiled bedding and cleaning cages can still have very substantial potential exposures in some facilities. The move to filtered cages appears to reduce general exposure, but filter changing and/or cleaning can lead to high exposures. In some facilities, animal receipt can cause significant exposures, as well as activities such as bleeding, culling and dosing; all activities involving the handling of animals outside of cages. We believe that the data presented may help those using air measurements in such facilities to improve their control of exposure to such aeroallergens, and thus reduce the risk of both sensitisation and subsequent allergic health problems, including the development of allergic asthma