The Prevalence of Occupational Asthma and Rhinitis among Animal Laboratory Workers at Health Sciences Laboratory Animal Services (HSLAS), University of Alberta; A cross-sectional Study

Abstract

Introduction: Laboratory animal allergy (LAA) is a recognised occupational health problem that can cause significant morbidity among exposed workers and imposes a burden on employers and industry. Since first described, many laboratories have introduced preventive measures to reduce the risk of allergy occurring, and the types of animals kept within many laboratories have also changed. Consequently, there is a need for up-to-date data regarding the epidemiology of LAA. Objectives: To study the prevalence of sensitization, occupational asthma and rhinitis to laboratory animal and to evaluate the association of potential work place risk factors in developing laboratory animal allergy at Health Sciences Laboratory Animal Services (HSLAS), University of Alberta. Methods: Animal husbandry staff (Group 1) and researchers (Group 2) were recruited from HSLAS together with graduate students not working with animals (Group 3). Sensitization was evaluated using skin prick tests (SPT) to laboratory animal allergens. Information on respiratory symptoms, atopy, current job tasks, job history and demographic information were recorded using a standardized questionnaire. A skin prick test was considered positive if it caused a wheal ≥3mm diameter. Work-related asthma or rhinitis was defined as relevant symptoms reported to be worse at work or better on vacation plus positive SPT to a relevant laboratory animal allergen. Results: The three Groups comprised of 57 ; 57 and 50 subjects. Among Group 1, 86% and 82% were working with mice and rats at the time of study and of those 27% and 57% were sensitized to mice and rats respectively. In Group 2 the number of exposed was lower with 13% and 54% sensitized to mice and rats while no one in Group 3 was sensitized to either mice or rat. Overall prevalence of occupational asthma and rhinitis to mice or rats was 15% and 28% respectively among the currently exposed Group. Atopy and several job tasks including animal sacrifice, shaving fur, injection and manual cage-cleaning were significantly associated with sensitization, occupational asthma or rhinitis. Conclusion: In spite of all the control measures and preventive modifications implemented in laboratory environments in the last several decades, laboratory animal allergy remained prevalent among exposed laboratory workers at HSLAS at the University of Alberta. Greater attention should be paid to those exposures occuring during the tasks identified as high risk in this study so as to prevent future health problems in laboratory animal workers.