Demodicosis

Pathogenesis and epidemiology

• Squamous demodecosis
  • Less serious
  • Dry reaction
  • Alopecia, desquamation and skin thickening
  • Absent to mild pruritus

• Follicular/pustular demodecosis
  • More serious
  • Skin invasion by staphylococci
  • Skin becomes wrinkled, thickened and contains pustules which ooze serum, blood or pus
  • Affected animals may be seriously disfigured
  • Severe pruritus is associated with secondary infection

• Immune factors are important in determining the severity and occurrence of demodecosis
  • Familial susceptibility
  • Immunosuppression
  • Immunosuppressant therapy

Diagnosis

• Liquid paraffin applied to a skin fold

• Deep skin scraping

Control

• Not easily accessible to acaricides due to their deep location in the skin

• Repeat treatments needed

• Recovery may take several months

• To aid acaricide penetration, clipping a dog's coat and washing is recommended

Dogs

Cats

• Rare

• Confined to the periocular region

• Mild squamous type only

Cattle

• Pea-sized nodules in the skin
  • Each nodule contains several thousand mites

• Affects hide quality
  • Economically important in Australia

Goats

• Becoming more common in goats

• Disease similar to that in cattle

Pigs, Sheep and Horses

• Rare