Prevalence of Demodex spp. in students and employees of the Pomeranian Medical University in Szczecin*

Katarzyna Dołęgowska


Introduction: Demodex folliculorum and Demodex brevis are mites living in the hair follicles and sebaceous glands of humans, with infestation usually being asymptomatic. In the present study the prevalence and number of mites, together with influencing factors of Demodex infestation, were investigated in students and personnel of the Pomeranian Medical University in Szczecin in Poland (PUM). The prevalence of 2 Demodex species, Demodex folliculorum and Demodex brevis, was compared in epilated eyelashes and skin scrapings derived from healthy volunteers.

Materials and methods: The study was conducted on 217 healthy volunteers – females and males. The study group consisted of 114 students and 103 employees of PUM. From each study participant, 2–3 eyelashes from each lid were epilated. From 99 volunteers, skin scrapings and/or secretions from sebaceous glands were also obtained. Demodicosis was diagnosed when Demodex eggs, larvae or adult mites were identified under microscopic examination.

Results: The infestation rate of Demodex (in epilated eyelashes and skin) among the 217 volunteers was 21%. Prevalence of hair follicle mites among personnel and students were 28% and 14% respectively. The mean number of mites among the 217 patients was 2.52 ±2.48 (3.16 ±2.9 in PUM personnel and 1.46 ±0.83 in students). The infestation rate increased with age (p = 0.0005). Demodex folliculorum infested 78% (p = 0.005) of the participants and 87.5% of epilated eyelashes (p = 0.000001). Demodex brevis was more frequent on the skin (67%; p = 0.00001). Hair follicle mites were detected more often in epilated eyelashes originating from the lower lid (p = 0.000001). Moreover, a weak correlation between the presence of selected symptoms (blepharedema, conjunctivitis, burning and itching of eyelids) and Demodex infestation was observed. There was no statistically significant association between Demodex infestation and an influencing factor: work using a microscope (p = 0.92).


Demodex mite; demodicosis; Demodex folliculorum; Demodex brevis.

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