Fauna and distribution of house dust mites in two northern districts of Kerala, India

This preliminary survey of house dust mites was carried out in two districts in Northern Kerala i.e., Malappuram and Kozhikkode. The study was conducted from December 2021 to November 2022. Collection of dust samples was done from a total of 160 houses, which were randomly selected 40 rural houses and 40 urban houses from each of the districts. A total of 6382 mites were collected from 147 houses. The most abundant species obtained from all the collected sites was the Dermatophagoides pteronyssinus(Trouessart) (67.69%) followed by the speciesBlomia tropicalisBronswijk,Cock & Oshima (27.5%).Other species obtained were Sturnophagoidessp.,Cheyletus eruditus (Schrank), Cheyletus malaccensis Oudemans, Glycycometussp., Tyrophagus putrescentiae(Schrank), Chortoglyphus arcuatus(Troupeau), Suidasiasp. The mean number of mites present in Malappuram and Kozhikode districts showed a statistically significant difference. Also, the mean number of mites present between urban houses and rural houses differed significantly. A statistical test (Fischer's exact test) was performed to analyze the influence of weather parameters, viz., temperature and relative humidity on the presence of mites in the surveyed houses revealed that the mite population is dependent on relative humidity and independent of temperature.