Introduction and objectives At least 12000 people work with laboratory animals in the UK. Approximately 15% of exposed employees develop specific IgE sensitisation and 10% clinical symptoms of laboratory animal allergy (LAA), a form of occupational asthma. Individually ventilated cages (IVCs) are increasingly replacing conventional open cages (primarily to protect mice from external infection) and whilst this can be associated with lower levels of ambient aeroallergen levels no corresponding reduction in the incidence of LAA is apparent. The SPIRAL (Safe Practice In Reducing Allergy in Laboratories) study is a large multi-centred study designed to increase understanding of the complex association between workplace exposure to mouse allergens and development of sensitisation, and to evaluate the risk of working with mice today.
Methods A cross-sectional study of animal workers at seven UK medical research institutions is in progress. We aim to recruit 250 people working in IVC-only facilities and 160 people working in mixed facilities; our primary outcome is a comparison of prevalence of sensitisation to Mus m 1 (mouse urinary antigen) between these two groups. Participants are invited to complete a detailed online questionnaire about work tasks and practices. Skin-prick tests to common aeroallergens and various animal proteins are performed and blood samples analysed for serum specific IgE to Mus m 1. Aeroallergen sampling for particular matter and Mus m 1 is undertaken concurrently to provide additional information about potential exposures. Recently employed individuals are invited to participate in a cohort study to determine incidence rates of laboratory animal allergy.
Results 136 individuals have been recruited to date; Table 1 shows their demographics and preliminary immunology results. Prevalence of allergic symptoms and sensitisation is similar to that anticipated.
Conclusion The SPIRAL study is the largest, most detailed study of LAA to be carried out. It aims to increase understanding of the relationship between allergen exposure and risk of sensitisation with the goal of significantly reducing the incidence of LAA. The results will be used to develop a “Code of best working practices” for facilities using IVC systems, nationally and further afield.