Molecular identification and phylogenetic relationship of Demodex mites based on mitochondrial 16S rDNA.

BACKGROUND AND OBJECTIVE: Demodex mites are tiny parasites that live around hair follicles of mammals. The two main species of Demodex i.e. Demodex folliculorum and Demodex brevis present in humans are found near the hair follicles of eyes. The present study was to understand the presence of Demodex mites in people suffering from blepharitis in Amritsar, Punjab. MATERIAL AND METHODS: Demodex mites samples present in blepharitis patients were isolated from the eyelashes. DNA was isolated from three mites and used for PCR amplification of mitochondrial (mt) 16S rDNA. The amplified PCR product were purified and used for molecular identification. RESULTS: The amplified mt16s rDNA product was sequenced and subjected to BLAST search in the NCBI database for molecular identification. The identified mite belongs to Demodex folliculorum species. The phylogenetic tree constructed by using mt16s rDNA sequence suggests that D. folliculorum is closer to D. canis than to D. brevis. CONCLUSION: All the three isolates belong to D. folliculorum and the mitochondrial DNA 16S rDNA partial sequence is applicable for phylogenetic relationship analysis.

Seasonal Variation of Allergenic Acarofauna From the Homes of Allergic Rhinitis and Asthmatic Patients.

House dust mites (HDMs) play positive role in causing various kinds of allergenic manifestations such as allergic rhinitis (AR), asthma, dermatitis, and urticaria. HDMs are prevalent in temperate regions but various studies have shown the prevalence of HDMs in tropical and subtropical countries. The present study was conducted from March 2015 to February 2016. During the study period, a total of 500 dust samples were collected from 125 homes of 125 patients suffering from AR and asthma. From these 500 dust samples, 466 samples were found to be positive for mites. The year was divided into three climatic classes, i.e., CCL I (March, April, May, June), CCL II (July, August, September, October), and CCL III (November, December, January, February) A total of 7,710 mites were collected, from which 2,902 (37.63%) mites were found in samples collected during summer season, i.e., CCL-I, 3,728 (48.35%) mites were found in samples collected during rainy season, i.e., CCL-II and only 1,080 (14.01%) mites were found in samples collected during winter season, i.e., CCL-III. Total 7,710 mite specimens were isolated with 7,404, i.e., 96.03% were only from the hypoorder Astigmata, 240, i.e., 3.11% from suborder Prostigmata, 46, i.e., 0.60% from order Mesostigmata, and 20, i.e., 0.26% from suborder Oribatida. The present study indicates that Dermatophagoides pteronyssinus (Trouessart 1897) (Astigmata) was most abundant and frequently found allergenic mite species followed by D. farinae (Hughes 1961), D. microceras (Griffiths and Cunnington 1971), Acarus siro (Linnaeus 1758), Tyrophagus putrescentiae (Schrank 1781), Lepidoglyphus destructor (Schrank 1781), Euroglyphus maynei (Cooreman 1950), Cheyletus, Mesostigmatic, and Oribatida mites.