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Influence of floor levels on the prevalence of house-dust mites in apartments in Nagoya, Japan

1992; Japan Society of Medical Entomology and Zoology; Volume: 43; Issue: 4 Linguagem: Inglês

10.7601/mez.43.307

2185-5609

Chiharu SUTO, Ikuko SAKAKI, Hideko ITOH, Masataka MITIBATA,

Insects and Parasite Interactions

In order to investigate the influence of housing conditions on the prevalence of house-dust mites in concrete apartment buildings in and around Nagoya City, mite surveys were conducted in living rooms and bedrooms of 20 apartments on the 1st to 10th floors from September 1983 to June 1984 at about 3-month intervals. Allergic children were found in 16 apartments. The mite fauna did not differ much from previous reports : Dermatophagoides farinae (D.f.) and D. pteronyssinus (D.p.) were predominant, constituting about 82% of the totals, followed by Haplochthonius simplex, Euroglyphus maynei, Glycyphagidae, Cheyletidae, Acaridae, Cosmochthonius reticulatus, and Tarsonemidae. A significant negative correlation was found between the percentage compositions of D.f. and D.p. : D.p. had a tendency to predominate over D.f. in apartments with more than 4 members in a family, less than 0.8 of the room ratio (No. of rooms/family size), and on floor levels below the third floor. The numbers of D.p., Glycyphagidae, Tarsonemidae, and C. reticulatus were greater in low-floor apartments (below 3rd) than in high-floor apartments (above 4th). while the numbers of D.f., Acaridae, and Cheyletidae did not greatly vary with the floor levels. These results suggested that household activities and the distance from the ground level were limiting factors for the prevalence of house-dust mites in apartments. The cause of the habitat segregations was considered to be mainly due to the interaction of humidity requirements in mites and the dampness of microhabitats. The mite communities were more complicated in low-floor apartments than in high-floor apartments. The number of allergic children was also greater in low-floor apartments. These data suggested a relationship among the housing conditions, prevalence of mites, and allergic sensitization.