Abstract
Purpose:
The aim of the study was to identify substances that can effectively eliminate Demodex spp. Gao et al. (2005) indicated on the harmful effect of tea tree essential oil on Demodex spp. We have attempted a comparative analysis of the impact of essential oils obtained from various plant species on the survival rate of Demodex spp. We have also sought to reveal which ones are the most effective.
Methods:
The material investigated were live Demodex mites collected from the eyelashes of patients subjected to examination to test the presence of these mites. Immediately upon collection, live mites were placed on the surface of glass microscope slide to study their mobility under the microscope. Subsequently, live Demodex mites were immersed in a drop of essential oil and placed in a closed moist chamber in order to avoid oil evaporation. Mite behaviour was inspected by means of a microscope in terms of their mobility at different time intervals. Included in the study were essential oils derived from the following plant species: tea tree, sea buckthorn, aloe, sage, peppermint, camphor, fennel, eucalyptus and lavender.
Results:
Upon the investigation of respective essential oils, their effectiveness proved to differ. Some oils caused rapid mites death, in as little time as several or between ten to twenty minutes, while for others it took several hours or days. 50% tea tree oil (mean survival rate - 7 minutes), sage oil (mean survival rate - 7 minutes) and peppermint oil (mean survival rate - 11 minutes) were established to show an optimal effect. Demodex mites survived for the longest period when exposed to seabuckthorn and aloe essential oils - 3 days and 9 hours, respectively. The study was controlled by the observation of mite performance in physiological saline solution with a mean survival rate of 82 hours and a maximum survival period of over 6 days. Basing on the analysis of the effectiveness and chemical composition of respective essential oils, terpene content in essential oils is most probable to have a lethal effect on Demodex mites.
Conclusions:
Essential oils derived from tea tree, sage and peppermint are an effective means against eyelash mites.
Keywords: 422 antibiotics/antifungals/antiparasitics •
526 eyelid •
636 pathobiology