Qualitative and quantitative assessment of mites (Acari) in domiciliary dust in rural dwellings in the "Zona da Mata" region, Minas Gerais, Brazil

From July to September, 2000 (winter), and from January to March, 2001 (summer), 30 dust samples were collected for each season, from beds of rural dwellings located in farms in the geographical area named "Zona da Mata", Minas Gerais, Brazil. After being sorted, the mites were identified and quantified. The prevalence of mites in the samples was 100%. 891 mites were found in winter (22.97%), and 2988 in summer (77.03%). In winter, Dermatophagoides pteronyssinus (Trouessart, 1897) was the most prevalent (55.00%), followed by Blomia tropicalis (Bronswijk, Cock & Oshima, 1973) (27.06%), Euroglyphus maynei (Cooreman, 1950) (8.85%), and predator mites from Cheyletidae family (8.07%). In summer, the most prevalent species was B. tropicalis (47.79%), followed by D. pteronyssinus (43.38%), Cheyletidae (6.87%), and E. maynei (1.28%). Few Dermatophagoides farinae (Hughes, 1961), Chortoglyphus arcuatus (Troupeau, 1879), and mites from Tarsonemidae and Cunaxidae families were found, the last two occurring only in summer. No mites from Acaridae family were found. The greatest number of immature forms found in summer suggested a greater breeding activity in this season. It was also noted that different building materials and varied cleaning routines may influence the population size of domiciliary dust mites.