Development of Semi-Nested PCR for Detecting Demodex folliculorum และ D. brevis

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ปวันรัตน์ ตรีขัน
กัญญรัตน์ กรัยวิเชียร
อัจฉรา ภูมี
เผด็จ สิริยะเสถียร


Demodex are tiny ectoparasitic mites, live in sebaceous glands. There are only two species, D. folliculorum and D.brevis found in human. Identification between both species could be done based on the morphological appearance of the adult stage. However for other stages especially egg and nymph, they are indistinguishable, therefore it causes difficulty for epidemiology study. This present study proposed the using of molecular technique for detecting and differentiation between these two human Demodex species. Primers were designed based on 18SrRNA gene of human Demodex mites. The 18SrRNA gene is usually used for Acari arthropods evolution studies because of its high variability. Total DNA was extracted from skin samples and was used to amplify the himan Demodex mite by using Semi-Nested PCR. The PCR was able to amplify the 18SrRNA gene from both human Demodex mite species with approximately 382 bp and 317 bp for D. folliculorum and D.brevis, respectively. The data obtained from the study provides fundamental data for accurate identification of the human Demodex and therefore for futher epidemiological study in the future. In addition, this report is the first study using molecular techniques to investigate human Demodex in Thailand.


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