| Demodex mite |
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| Binomial names |
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Demodex folliculorum hominis,
Demodex brevis, Demodex canis |
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The demodex mite is a tiny parasitic mite which lives around human hair follicles, particularly those of the eyelashes and eyebrows (Demodex folliculorum hominis) or in sebaceous glands connected to hair follicles (Demodex brevis). Measuring between 0.1mm and 0.4mm, each mite has eight segmented legs for locomotion, a long, scale-covered body for anchoring itself in the hair follicle, and pin-like mouth-parts for eating skin-cells and oils which accumulate in the hair follicles. Interestingly, the mite's digestive system is so efficient and results in so little waste that there is no excretory orifice!
With a life cycle lasting around two weeks, the mites are transferred between hosts through contact of hair, eyebrows and of the sebaceous glands on the nose.
A surprising fact is that an estimated 96-98% of all people carry such mites - with up to 25 in each follicle, each person can have a potentially huge population of mites. In the vast majority of cases, the mites go unobserved, without any adverse symptoms, but in certain cases (usually related to a suppressed immune system, caused by stress or illness) mite populations can dramatically increase, resulting in a condition known as demodicosis, characterised by itching, inflammation and other skin disorders.
It is quite easy to look for your own demodex mites, by carefully removing an eyelash or eyebrow hair and placing it under a microscope.
A related species of demodex mite, (Demodex canis), lives on the domestic dog. While, like with humans, most dogs live with their mites without harm, a minority do not have immune systems capable of completely controlling the mites, leading to a potentially dangerous infestation called demodectic mange. While direct treatment for severe cases is possible using a drug known as Mitaban which is applied to the animal's skin, improved nutrition and checking for other, immune-system suppressing diseases are also recommended.
External links
- Demodex, an inhabitant of human hair follicles, and a mite which we live with in harmony, by M. Halit Umar, published in the May 2000 edition of Micscape Magazine
- Demodicosis, an article by Manolette R Roque, MD
- Eyelash Creatures
- Mites might cause mighty problems, USA Today (Magazine), Feb 2004
- Demodex in the Dog, by T. J. Dunn, Jr. DVM
