Objectives To identify modifiable factors associated with sensitisation to laboratory animals.

Method Animal husbandry staff (group 1) and researchers (group 2) were recruited from a University animal facility together with health researchers not working with animals (group 3). Sensitisation was evaluated using skin prick tests to rat and mouse allergens. Current tasks, job history and demographic information were recorded.

Results The 3 groups comprised: 57; 57; and 50 subjects. Among group 1, 88% were currently working with rats, and 88% with mice: 51% were sensitised to rat, 28% to mouse. In group 2 the numbers exposed were lower (75% rat, 58% mice) as was the rate of sensitisation (32% rat, 12% mouse). No one in group 3 was exposed or sensitised. Among those currently exposed, sensitisation to rat was associated with shaving of fur and disposal of soiled litter, and with less frequent use of female rats. Sensitisation to mice was higher in those with contact with mouse urine and saliva, but not related to specific tasks. In multiple regression models, sensitisation to rat was only associated with use of female rats (OR 0.25, 95% CI 0.01–0.64). Sensitisation to mouse was greater in women (OR 6.67, 1.20–36.98), those born on a farm (OR 4.65, 1.05–20.55) and with exposure to mouse saliva (OR 4.26, 1.23–14.76).

Conclusions Exposures were highly correlated, making it difficult to identify specific modifiable risk factors. However it is of note that, since male rats use urine to mark territory, the greater use of exclusively female rats should serve to reduce sensitisation.