Aims: To determine the frequency of sensitisation to mites among rhinitic laboratory animal workers and to clarify whether sensitisation could be occupational. Methods: Skin prick tests (SPT) were performed in 40 subjects who were working with laboratory animals in Kuopio University research units and who had been referred to Kuopio University Hospital for work related rhinitis. The SPT panel consisted of three storage mites, two house dust mites, 11 other common environmental airborne allergens, latex, and 2-4 individually relevant laboratory animals. To determine signs of mites in animal facilities, guanine was determined in 22 dust samples taken from feedstuffs or bedding material used for laboratory animals and from rooms where these materials were stored and handled. Results: Positive SPT results were found in 35 out of 40 workers: in 14 for storage mites, four for house dust mites, 25 for other common aeroallergens, as well as positive reactions to laboratory animals in 19 individuals. The guanine test was positive, indicating the presence of mite derived material in 21 out of 22 dust samples. Conclusions: This study suggests that subjects who are occupationally exposed to laboratory animals are also exposed to mite derived allergens. Sensitisation to mites is common and may be work related. W ork related respiratory symptoms are an important health problem among laboratory animal workers and rhinoconjunctivitis is the most common complaint.1 Rhinoconjunctivitis may be caused by laboratory animal allergy (LAA), which is a well known occupational hazard. The prevalence rate of LAA is between 20% and 40%.
1In cases where no specific sensitisation to laboratory animals has been revealed in clinical examination, the work related symptoms have been considered as resulting from nonspecific hyperresponsiveness to animal derived or other agents, such as dust, disinfectants, or ammonia that also are present in laboratory animal facilities.2 When a group of laboratory animal workers were examined in our clinic for work related rhinitis, our attention was drawn to numerous positive skin prick test (SPT) results for at least one of the three storage mites that were included in the routine test panel. This provided the impetus to determine the actual frequency of sensitisation to mites, especially to storage mites, among rhinitic laboratory animal workers. Another aim was to clarify whether this sensitisation could be occupational. There are no previous reports of sensitisation to mites in animal work.
MATERIAL AND METHODSThe study subjects consisted of 40 rhinitic animal workers. They were exposed to laboratory animals in the research units of the University of Kuopio, where about 250 people are working with animals at any given time. In a questionnaire study, 65 out of 254 employees reported work related rhinitis and 47 of them had been examined for LAA.3 Those 40 rhinitic animal workers, who in that connection were also tested for mites, constitute the subjects of the present study.There were 24 researchers, 10 labo...