[The importance of house dust mites and stored food mites as house dust allergens in the rural population].

House dust samples from rural districts contain more mite species (in particular stored food mites) than samples from urban areas, and the total number of mites is also approximately three times greater. 77 patients from rural districts, 48 of whom allergic to their own house dust, and 29 controls, were tested with mite extracts from Dermatophagoides pteronyssimus, D. farinae, Chortoglyphus arcuatus, Acarus siro, Glycyphagus destructor and Tyrophagus putrescentiae, and a house dust extract. Out of 32 patients who showed positive scratch tests to one or more mite extracts, 29 (90,6 percent) reacted positively to D. pteronyssimus, 25 (78.1 percent) to D. farinae and from 7 to 12 (20-40 percent) to the stored food mites. Out of the 48 patients allergic to their own house dust, 27 (56.2 percent showed positive reactions to D. pteronyssinus, 24 (50.0 percent) to the house dust extract and 21 (43.7 percent) to D. farinae. Only 5 (17.2 percent) out of the 29 controls reacted positively to one or more of the solutions tested. The stored food mites showed 2.5 to 4.5 times more positive reactions in the rural patients compared with the results obtained in urban patients. The importance of these mites in the sensitization of patients from rural districts is discussed.