Differences in mite fauna between the continental and Mediterranean climates of Croatia: microscopy and Dustscreen test findings.

Background: The aim of this study was to evaluate the difference between the mite fauna in the inland and coastal Croatia.

Methods: Ninety-nine floor house dust samples were collected: 28 from the coastal area, 31 from the inland rural and 40 from the inland urban area. Data on basic household characteristics were collected for 81 of 99 households. The mites were separated from the dust using the floatation method and then microscopically identified. The levels of Dermatophagoides pteronyssinus (Der p) 1, Dermatophagoides farinae (Der f) 1 and Der 2 were measured using the Dustscreen test. Ordinal descriptive statistics and nonparametric tests were used for data analysis, assuming statistical significance at P < 0.05.

Results: More than 70% of mites identified in all areas were pyroglyphids. Nonpyroglyphid mites accounted for 20-25% of all identified mites in the coastal areas (Blomia, Lepidoglyphus and Glycyphagus) and with 15% in the inland areas (Lepidoglyphus and Acarus). The highest Der p 1 median levels were found in the coastal area, with significantly lower levels in the inland rural and inland urban areas (4.5; 2; 0.85 microg/g of dust; P = 0.0001). The highest Der f 1 median levels were found in the inland urban area, with significantly lower levels in the inland rural and coastal areas (0.88; 0.75; 0 microg/g of dust; P = 0.0013). The levels of Der f 1 were significantly higher in samples taken from households with central heating than from those with traditional heating (1; 0.25 microg/g of dust; P < 0.01).

Conclusions: Separate diagnostic dust mite lists for the coastal and inland areas because of climatic and dwelling differences required to be implemented. Compared with traditional heating, central heating significantly increases the risk of exposure to Der f 1 levels >2 microg/g of dust (odds ratio, 7.35; 95% confidence interval, 1.43-37.87; P = 0.01).