Cat allergen levels in public places in New Zealand

AIMS: Cat allergen (Fel d 1) is a known risk factor for asthma. Studies have demonstrated Fel d 1 in both public buildings and domestic dwellings where cats have never been. The aims of this study were to measure reservoir Fel d 1 levels in public buildings in New Zealand, to examine determinants of these levels and to compare them with previously measured domestic levels. METHODS: Dust was obtained in two centres (Wellington and Christchurch) from hotels, hospitals, rest homes, churches, primary schools, childcare centres, cinemas, bank head offices and aeroplanes; and from North Island ski lodges. Measurements of temperature and relative humidity were taken. Information was collected on building characteristics. Fel d 1 levels (microg/g of fine dust) for floors (n=203), beds (n=64) and seats (n=24) were expressed as geometric means (95% confidence intervals). RESULTS: Detectable Fel d 1 levels were found in 95% of floor samples, 91% of bed samples and 100% of seat samples. Fel d 1 levels [geometric mean (95% confidence intervals)] were significantly higher on cinema and domestic aircraft seats [36.8 (20.8-65.3) microg/g and 33.3 (28.0-39.7) microg/g respectively] than on floors [3.6 (2.5-5.1) microg/g and 2.4 (1.8-3.0) microg/g respectively]. Floor Fel d 1 levels in the public buildings sampled were lower than those of domestic dwellings without cats [0.9 (0.6-1.4) microg/g vs 1.7 (1.2-2.4)] microg/g in Wellington and [2.0 (1.6-2.6) microg/g vs 4.0 (2.7-6.0] microg/g in Christchurch. After controlling for potential confounders, floor Fel d 1 levels were higher with carpeted floors (p<0.001) and lower in banks and hospitals (p<0.001). CONCLUSION: Fel d 1 levels in public buildings are low in New Zealand public places except for cinema and domestic aircraft seats where all but one sample had Fel d 1 levels potentially high enough to precipitate asthma symptoms in sensitised individuals.