Felis ISSN 2398-2950

Otodectes cynotis

Synonym(s): O. cynotis, ear mite

Contributor(s): Susan Dawson, Rosanna Marsella, David Scarff

Introduction

Classification

Taxonomy

  • Family: Psoroptidae.
  • Genus: Otodectes.

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Clinical Effects

Epidemiology

Habitat

  • Deep in the ear canal of cats, dogs, foxes, other Canidae and Felidae, and ferrets.
  • May spread to the pinna, neck, head, rump, paws, tail tip.

Lifecycle

  • O. cynotis life cycle Lifecycle: Otodectes cynotis - diagram :
    • Adult male Otodectes cynotis: adult male and female Otodectes cynotis: female .
    • Egg Otodectes cynotis: egg in feces of dog .
    • Larva Otodectes cynotis: larva hatched from egg .
    • Nymph.

Transmission

  • Permanent parasite of the ear, therefore transmission by close, direct contact, particularly mother to young while suckling, but also in catteries, etc.
  • O. cynotis seems not to be host-specific so transmission occurs between different host species, especially the cat and dog.
  • O. cynotis can be maintained in vitro on ear debris and survives in the environment, but the importance in transmission of environmental contamination with mites remains unsubstantiated.

Pathological effects

  • Infection induces a pruritic, hypersensitivity reaction.
  • Consists of an immediate (Type I) and arthus (Type III) hypersensitivity reaction.
  • Marked infiltration of wall of ear canal with plasma cells and lymphocytes.
  • Severe pruritus, head shaking and scratching.
  • Excess cerumen production exuding as a dark brown colored, waxy discharge that can crust. Mites live beneath the crust next to the skin.
  • May lead to purulent otitis with invasion of neutrophils and a brown, purulent, fetid discharge.

Other Host Effects

  • Surface parasites feeding on epidermal debris and excess cerumen.

Control

Control via animal

  • Treatment of cat and all in-contact animals.
  • Remove wax and cleanse ear canal.
  • Most acaricidal ear drops or ointments have little or no residual activity so many treatments are given daily, and treatment should be repeated at least twice at 10-14 days to kill mites hatched from eggs present at the time of treatment.

Control via chemotherapies

Either

  • Amethocaine hydrochloride/neomycin sulfate Neomycin  /thiabendazole Tiabendazole (ear drops).
  • Diethanolamine fusidate Fusidic acid  /framycetin Framycetin  /nystatin Nystatin  /prednisolone Prednisolone (ear drops).
  • Piperonyl butoxide/pyrethrins (ear drops).
  • Amethocaine hydrochloride/neomycin sulfate Neomycin  /permethrin (ear drops).
  • Chlorbutol/phenoxyethanol (ear drops).
  • Thiabendazone/dexamethasone/neomycin sulfate.

Or

Effective acaracides

  • Ivermectin Ivermectin  (200-400 ug/kg) by injection used at least twice is effective (unlicensed use).
  • Interval of 14 days.
  • Fipronil (topical application in ears once) - unlicensed use in cats.

Control via environment

  • The relevant importance of mites in the environment is unknown. Repeated treatment of the cat at about 10-day intervals should eliminate any reinfestation from the environment.
  • In persistent cases, remove and boil bedding and clean or treat the area where the cat sleeps with acaricide.

Other countermeasures

  • In persistent cases it may be useful to treat the whole body with an amitraz Amitraz bath, or lime-sulfur dip.
    Cats may experience severe adverse reactions to amitraz Amitraz toxicity.

Diagnosis

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Further Reading

Publications

Refereed papers

  • Recent references from VetMedResource and PubMed.
  • Rosychuk R A (1994) Management of otitis externa. Vet Clin North Am Small Animal Pract 24(5), 921-951.
  • Chickering W R (1988) Cytologic evaluation of otic exudates. Vet Clin North Am Small Anim Pract 18(4), 773-782.
  • Colman B J (1981) Helminth parasites and arthropods of feral cats. Aust Vet J 57(7), 324-327.
  • Klayman E et al (1981) Diagnosis of ectoparasitism. Mod Vet Pract 62(10), 767-771.
  • Powell M B, Weisbroth S H, Roth L et al (1980) Reaginic hypersensitivity to Otodectes cynotis infestations of cats and modes of mite feeding. Am J Vet Res 41, 877.
  • Pott J M et al (1979) The efficacy of a topical ear preparation against Otodectes cynotis infection in dogs and cats. Vet Rec 104(25), 579.

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