Otodectes cynotis

Otodectes cynotis (Courtesy of C. Antonczyk)

• Causes otodectic skin infestation

• Commonest mange of dogs and cats in the world

• Inhabits the inner ear

• Also found in the fox and the ferret

• Closed keratinous bars (apodemes) on ventral surface

• Life cycle takes 3 weeks

• Feeds on ear debris

Pathogenesis

• The majority of cats harbour the mites, however only a few show symptoms
  • Transmission occurs whilst kittens are suckling

• Common cause of otitis externa in dogs

• Brown waxy exudate produced

• Can lead to secondary infection

• Clinical signs are apparent
  • Head shaking
  • Ear scratching
  • Aural haematomata

Treatment

• Acaracidal ear drops
  • Massage base of ear to disperse drops after treatment

• Most treatments need to be repeated in 10-14 days to kill newly hatched mites

• Selamectin can be used as a spot-on treatment
  • Prolonged duration of action

• Treat all in-contact animals
  • These may be asymptomatic carriers