Article originally written by Indrakala Khatri , B.V.Sc and A.H, IAAS
- Demodex is a genus of very minute follicular mites (family: Demodicidae) that inhabit the skin and are usually found in the sebaceous glands and hair follicles of mammals.
- They are considered to be host-species specific and some can be infested with two or more distinct species such as;
- D. canis ( in dog)
- D. injai (in dog)
- D. Brevis ( in human)
- D. folliculorum ( in human)
- D. bovis (in cattle)
- D. caprae (in goat)
- Long and thin, like a cigar and usually about 0.25 mm long.
- Body have head, thorax with four pairs of stumpy legs and elongated abdomen.
- Mouth with paired of palps and chelicerae and an unpaired hypostome.
- In male penis protrude dorsally while in female vulva protrude ventrally
- Eggs – spindle shaped
Complete entire lifecycle within hair follicle and sebaceous glands of single host at about 20-35 days (D. canis).
- Usually non pathogenic; remain as commensals under normal health condition.
- but under immunosuppressive condition due to stress/illness mite (D. canis) proliferate and demodicosis (demodectic mange) is diagnosed.
- Infection may be localized, generalized or pododermatitis
Demodicosis can manifest as lesions of two forms :
A. Squamous form
Distended hair follicles with mites and cellular debris.
Follicular epithelium is atrophic.
Hyperpigmentation with copper- red color skin.
Thickened skin and mousy odour.
B. Pustular form
Suppurative bacterial invasion of dermis.
Extensive dermal infiltration of polymorphonuclear leucocyteses and lymphocytes.
Abcess formation with marked inflammation.
Inextensive form of canine demodicosis, death results from toxaemia or emaciation.
- Slight to moderate itching.
- Patchy hair loss and leaves bald.
- Red, weepy infected areas.
- Cornified materials exfoliate from surface.
- Thickened skin.
- By finding mites in
- Contents of abscess
- Skin scraping: initially skin is pinched or squeezed gently then, scraped with dull tool like back of scapel blade; deep enough to assure sampling of hair follicle until tiny bleeding by capillary oozing. Finding many mites in scrapped material under microscope diagnosed an infection.
- Pets with cancer, hypothyroid diseases, allergies, heart worm infection may develop mange infection so following test may be done.
- Fecal exams.
- Blood test for heart worm, liver and kidney function.
X-ray for lymphocarcinoma
7. Differential diagnosis
- Amitraz ( mitaban dip) : 1 bottle of amitraz with 2 gallons of warm water( 250ppm).
- Ivermectin : 0.4 – 0.6mg/kg, PO, once daily.
- Bacitracin topical
- Milbemycin : 0.5-2mg/kg orally once daily for three month