Abstract
Mite dust was collected from the residences of 5 bronchial asthmatic patients and 5 non-asthmatic persons, living in and around Urasoe city, Okinawa Prefecture from Oct. 1990 to Oct. 1991
The number of mites had raised 2, 038 to 61, 200 and 2, 125 to 81, 000 in 1g fine dust collected from the houses of the asthmatic and non-asthmatic groups, respectively. An Increase of mites was observed in both April and May. Dermatophagoides pteronyssinus was a dominant species in all houses throughout this period.
Dp. occupied about 72.8-96.1% in the distribution of the mites in fine dust of all houses. On the other hand, Dermatophagoides farinae was found to be very low in fine dust, being under 0.6%.
There was no significant difference in seasonal appearance of mites between asthmatic and non-asthmatic groups.
It seemed that the frequency of asthma attack increased in April and May due to increasing numbers of mites. But there was an observation of a high asthma attack rate during October to January as well, in spite of the lowest number of mites during this period. In conclusion, there was no significant means between the number of mites and the frequency of asthma attacks in the winter period.
