木造および高層集合住宅におけるヒョウヒダニ類の生息状況に対する居住環境の影響

Abstract

To examine the influence of environmental conditions in human dwellings on the prevalence of house dust mites, Dermatophagoides spp., house dusts were sampled from living rooms and bedrooms of wooden Japanese-style and concrete apartment houses in and around Nagoya City, from September 1983 to June 1985 at about 3-month intervals. Mites were isolated using a floatation method. In the wooden houses, the annual mean density of D. farinae (D. f.) showed positive correlations with the number of rooms or the room ratio (the number of rooms to the family size), which was taken as an index of household activities, and a negative correlation with the family size. No significant correlation, however, was found between the mean density of D. pteronyssinus (D. p.) and the number of rooms, the room ratio, or the family size. From these results, household activities, which are generally high in the houses with lower room ratio, smaller number of rooms, and larger family size, and related with indoor humidity, were noted to be a principal factor influencing the distribution and abundance of D. f. in the wooden houses. By contrast, in the apartment houses the annual mean density of D. p. showed a positive correlation with the family size, and a negative correlation with the room ratio. No significant correlation was noted between the mean density of D. f. and the family size or the room ratio. The number of D. p. reduced inversely with the level of the apartment houses, but that of D. f. did not largely vary with the level. Thus, household activities and the level from the ground appeared to be limiting factors influencing the prevalence of D. p. in the apartment houses. Positive correlations existed between the mean densities of either species from living rooms versus bedrooms of the wooden and apartment houses. No correlation was found between the mite densities and age of houses, or house dust load.