House dust mites

Definition. Mites belonging to the Family Pyroglyphidae, which are living in house dusts

Important species. Dermatophagoides farinae (Df) and Dermatophagoides pteronyssinus (Dp) are the most important species

Geographical distribution. Worldwide in temperate and tropical zone. Df is more dominant in less humid areas, whereas Dp is found mostly in high humid areas; in general the dominant species is Df in North America and Dp in European countries.

Life cycle. They develop through the stages of egg, larva, the first nymph, the second nymph, and adult. It takes a month in average to develop from eggs to adults, eating micro-organic materials. Their longevity is about 2 months.

Morphology. All species of house dust mites are very similar in morphology, sized 370-430 ㎛ in female and 300-350 ㎛ in male. Their body color is milky white. The fourth legs are significantly smaller than the others. The tegument is covered with fine wrinkles. Morphological differences between Df and Dp are the shape of bursa copulatrix in female, being a cup-shape in Df and flower-shape in Dp. In male, a pair of the first legs are extraordinarilly larger in Df, whereas not larger than the other three pairs in Dp. In case of larvae and nymphs, the wrinkles of d2-d3 are horizontal in Df whereas vertical in Dp.

Importance. Df and Dp produce the most important allergens causing allergic diseases.

Control and Prevention. Cleaning and keeping dry condition in houses are the most important, fundamental factors to control house dust mite populations. Direct control measures include the application of proper acaricides and washing of cover cloth of beds and pillows

Larva, nymph and female adult of the European house dust mite (Dermatophagoides pteronyssinus). Ventral view of slide-mounted specimens.

European house dust mite (Dermatophagoides pteronyssinus), male adult (ventral side of slide-specimen). This species and American house dust mite (Dermatophagoides farinae) are the most important, cosmopolitan species among house dust mites (Pyroglyphidae).