House dust mites in Iran.

In the Caspian Sea region of Iran asthma seems closely related to house dust allergy. Since a high proportion of house dust sensitive patients appear to be sensitive to house dust mites, an investigation was carried out to determine the occurrence, distribution and abundance of these species in Iranian house dust in order to assess their role and clinical importance in house dust allergy in Iran. Thirty-five samples of house dust collected from houses in the Caspian Sea region and five samples from other areas were examined for mites. The three pyroglyphid species Dermatophagoides pteronyssinus, D. farinae and Euroglyphus maynei, reported by European and Japanses workers to be common in house dust and to be a major source of house dust allergens, were found to occur in Iranian house dust and to account for nearly two-thirds of the total mit population present in the dust. Dermatophagoidex pteronyssinus was the most frequent and most numerous species recorded, occurring in 90% of the samples examined and forming 94% of the pyroglyphid and 60% of the total mite population. The frequency with which house dust mites were found in the Iranian Caspian Sea region coupled with the relatively high frequency of allergic bronchial asthma in this area suggests that they may well be an important precipitating factor in asthma in Iran.