Publication date: 

20 Jun 2019

Ref: 

Eur Respir J. 2019 Jun 20;53(6). pii: 1900171. doi: 10.1183/13993003.00171-2019. Print 2019 Jun

Author(s): 

Feary JR, Schofield SJ, Canizales J, Fitzgerald B, Potts J, Jones M, Cullinan P

Publication type: 

Article

Abstract: 

BACKGROUND: Historical data suggest 15% of laboratory animal workers develop IgE sensitisation and 10% symptoms of laboratory animal allergy (LAA), including occupational asthma. Individually ventilated cages (IVC) are replacing conventional open cages; we sought to evaluate their impact on the development of LAA. METHODS: We surveyed 750 laboratory animal workers and measured airborne Mus m 1 (mouse allergen) levels in seven UK institutions. We compared the prevalence of sensitisation to mouse proteins (by specific IgE assay or skin prick test) and of work-related allergic symptoms in IVC-only and open cage units. MEASUREMENTS AND MAIN RESULTS: Full shift Mus m 1 levels were lower in IVC than open cage units (geometric mean 1.00 ng·m-3 (95% confidence interval: 0.73-1.36) versus8.35 ng·m-3 (6.97-9.95); p<0.001) but varied eight-fold across the IVC units (GM range: 0.33-4.12 ng·m-3). Primary analyses on data from 216 participants with <3 years' exposure to mice revealed a lower prevalence of sensitisation in those working in IVC compared with conventional cage units (2.4% (n=2) versus9.8% (n=13); p=0.052). Sensitisation in IVC units varied from 0% to 12.5%; the use of fitted respiratory protection was less common in IVC units where prevalence of sensitisation was higher. Work-related allergy symptoms were more frequently reported by mouse sensitised individuals (46.7% versus 10.9%, p<0.001); and only by those working in open cage units. CONCLUSION: In contemporary practice, LAA is now largely preventable with the use of IVC systems and the judicious use of appropriate respiratory protection.