House dust mites in the city of Lime, Peru

Since mites are the most common house dust allergens, knowledge about the s pecies most prevalent in a region is important for diagnostic and specific immunotherapy purposes. In order to establish the prevalence of house dust mites in different city districts, 100 house dust samples were collected fr om different parts of Lima. Lima is a city of tropical climate located alon g the coast of the Pacific Ocean. The relative air humidity is 80-90% and t he various districts studied are located at altitudes ranging from 37-355 m eters. The mite Blomia tropicalis was the organism most frequently detected , being present in 59% of the house dust samples. Dermatophagoides pteronys sinus occupied second place (15.9%), followed by Chortoglyphus arcuatus and Tyrophagus putrescentiae. These four mites, taken together, represented mo re than 90% of the mites detected. No specimen of the species Dermatophagoi des farinae was detected. We conclude that B. tropicalis and D, pteronyssin us are the most common house dust mites in Lima. Considering the high preva lence of B. tropicalis in Lima and the fact that its cross-reactivity with antigens of the mites of the family Pyroglyphidae is minimal, we conclude t hat sensitization to this mite should be investigated separately in allergi c patients living in Lima.