Risk of exposure to house dust pyroglyphid mites in Poland

Abstract

During the period of 1989-2000, 335 house dust samples were collected from dwellings at 27 different localities in Poland. Mite allergen exposure was measured in house dust samples collected by performing of mite taxa determination and measuring of the mite allergen levels by a semiquantitative guanine method (Acarex(R) test). Mites were found in 158 of the samples examined (47.2%). A total 3,714 mites were isolated and 15 species identified, including four species from the family Pyroglyphidae (house dust mites). Among them, Dermatophagoides farinae (DF) was predominant (approximately 67% of the total count), followed by D. pteronyssinus (DP) (17.6%) and Euroglyphus maynei (EM) (1.6%). Hirstia chelidonis (HCh) was found for the first time in house dust samples in Poland. DF was predominant in Iwonicz-Zdroj (96.6%), Katowice (91.8%), Sosnowiec (89.4%), Chorzow (94.8%), Bytom (50.9%), Swiêtochlowice (96.7%) and generally in Upper Silesia (88.2%), whereas DP dominated in Lod (92.9%), Wodzislaw (80.9%), Krakow (45.6%) and Bielsko-Biala (24.8%). Only 14.3% of the mites collected were alive. Total mean number of domestic mites per gram of dust (in all samples examined) was 204.1 +/- 1079.8. The greatest number of mites per 1 gram of dust was 14,971.4. Mite densities and levels of mite allergens (expressed as Acarex test steps) in samples from beds, floors and upholstery furnitures at particular localities in Poland, and in dwellings of atopic versus non-atopic subjects were compared. Highest mite concentrations were usually found in dust from beds, carpets and shutters. D. farinae was distinctly more abundant both per 1 gram of dust and per 1 sample than the species D. pteronyssinus. Other pyroglyphid mites, E. maynei and H. chelidonis, occurred in very small numbers. No significant differences were found between the counts of mites (total and live) in the dwellings of atopic and non-atopic persons. Approximately 49.5% of samples showed positive levels of the mite allergens (Acarex test steps). An influence of some abiotic indoor factors on the mite prevalence in the examined dwellings was analysed separately in relation to samples of bed dust, floor dust and dust from upholstery furnitures. The density of mites was influenced mainly by the type of heating, temperature, type of sleeping accommodation, type of floor or furniture, sampling method, and type of building, whereas levels of the mite allergens were associated with the mite density, relative humidity, month, sampling method, type of building and type of heating.