Fauna and geographical distribution of house dust mites in Korea.

During the period of 1933-1994, house dusts were collected from 65 homes at 10 different localities by operating electric vacuum cleaners. House dust mites were isolated from 10 g dust by applying the modified wet sieving method. Total 7,257 mites were collected and 23 species were identified. Among them. Dermatophagoides farinae (DF) was predominant (65.3% of the total), followed by D. pteronyssinus (DP) (20.6%) and Tyrophagus putrescentiae (TP) (6.5%). Rhizoglyphus robini. Sancassania phyllophagianus, Cheyletus traussarti and Scheloribates latipes were the first findings from Korea. DF was predominant in Seoul (66.8%). Kwangju (63.6%), inland of Pusan (79.6%), Inchon (96.5%). Taejon (83.9%), Chonju (87.15) and Chongju (95.2%), whereas DP was predominant in Yongkwang-ub (72.5%) and Yongdo (island) of Pusan (64.9%), and TP in Chunchon (38.2%). The localities where DP and TP were predominant showed higher relative humidity in air (> 73% RH). Among 62 study homes, DF, DP and TP were found in 24.6% of the homes, co-habitat of two species in 48.1% and one species in 27.3%. DF was predominant in 63.5% of the homes studied. DP in 29.6% and TP in 6.9%. In 10 g of the house dust, less than 99 mites were found in 49 homes (70.0%), 100-499 mites in 11 homes (15.7%). 500-999 mites in 3 homes (4.3%) and more than 1,000 mites in 2 homes (2.9%). No mite was found in 5 homes (7.1%). In order to evaluate environmental factors affecting the population density of house dust mites, house type, age of house construction, size of the house, number of the family and frequency of the cleaning were compared with the number of mites, and none of the above factors were statistically correlated with the mite density.