A survey of mite allergens (Der 1) derived from dead mites, their feces, and numbers of mites was conducted in August 2010 to estimate mite infestations in the school environment. A vacuum cleaner was used to collect 232 dust samples from floors and bedding in 29 primary and secondary schools in Tokyo. The collected house dust was extracted with phosphate-buffered saline, and the supernatant was used to measure Der 1 by an enzyme-linked immunosorbent assay (ELISA). The mites in the sediment were then isolated by the saturated-saline flotation method. Only five samples (2%) from four schools exceeded the Standard Value of School Environmental Sanitation (100 mites per square meter). However, 73 of 232 samples (31%) exceeded 100 mites per gram dust, a WHO threshold for the development of IgE antibody and asthma, and 26 samples (11%) exceeded 500 mites per gram dust, another risk factor for acute attacks of asthma advocated by WHO. Genus Dermatophagoides, including Dermatophagoides farinae Hughes and D. pteronyssinus (Trouessart), dominated at rates exceeding 97% in carpets, tatami mats, and bedding, and 67% on wooden floors. From these results, 100 Dermatophagoides mites per square meter was equivalent to 353 ng of Der 1 in carpets, 711ng in bedding, and 546 ng on wooden floors. It was concluded that the Standard Value of School Environmental Sanitation was less strict than the WHO International Standard for mite allergen exposure.

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We attempted to collect bed bugs, Cimex lectularius Linnaeus, with two different kinds of sticky traps, paper and polypropylene, in an apartment in Toshima-ku, Tokyo, Japan. Paper traps were narrow with 1.0 cm-high inclined entrances; polypropylene traps were broad with 5.5 cm-high flattened entrances. One trap was located in each of the four corners in a room. A total of 151 bed bugs consisting of 100 nymphs and 51 adults was collected with paper traps during the investigation period. For polypropylene traps, a total of 279 bed bugs consisting of 227 nymphs and 52 adults was collected. There were significant differences between the nymphs and adults in bed bugs collected in polypropylene traps. The daily mean of bed bugs collected per unit area with polypropylene traps differed significantly among the sampling points. These results suggest that two different kinds of sticky traps were useful for collecting bed bugs, especially nymphs.

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[in Japanese]

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