[Biology of the house dust mite dermatophagoides pteronyssinus. II. Incidence of mites in the various regions of Switzerland and its dependence on climate].

Seasonal examinations of dust samples from Basel and surroundings have shown that the number of mites increases during the months of August through October. Dust samples were then collected from various climatic regions of Switzerland during August and tseptember. Samples originating from places where the temperature was above 12 degrees C and relative humidity above 68% over a period of 4-5 months yielded a high mite count. Regions with these climatic conditions are therefore unfavourable for patients allergic to house-dust.