Canis ISSN: 2398-2942
Otodectes cynotis
Synonym(s): O. cynotis, ear mites
Contributor(s): Rosanna Marsella
Introduction
Classification
Taxonomy
- Family: Psoroptidae.
- Genus: Otodectes.
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Clinical Effects
Epidemiology
Habitat
- Deep in the ear canal of dogs, cats, foxes, other Canidae and Felidae, and ferrets.
- May spread to the pinna, neck, head, rump, paws, tail tip.
Lifecycle
- O. cynotis lifecycle
:
- Adult male
and female
.
- Egg
.
- Larva
.
- Nymph.
Transmission
- Permanent parasite of the ear, therefore transmission by close, direct contact, particularly mother to young while suckling, but also in kennels, 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.
- This has been studied only in cats and consisted 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 dog 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 once at 10-14 days to kill mites hatched from eggs present at the time of treatment.
Control via chemotherapies
Either
- a) Amethocaine hydrochloride/neomycin sulfate/thiabendazole (ear drops).
- b) Diethanolamine fusidate/framycetin/nystatin/prednisolone (ear drops).
- c) Piperonyl butoxide/pyrethrins (ear drops).
- d) Amethocaine hydrochloride/neomycin sulfate/permethrin (ear drops).
- e) Chlorbutol/phenoxyethanol (Otodex ear drops).
- f) Thiabendazone/dexamethasone/neomycin sulfate.
Or Effective acaracides:
- a) Amitraz Amitraz (0.025% in mineral oil), by topical application and used at least twice, is effective (unlicensed use in dogs).
- b) Ivermectin Ivermectin (200-400 ug/kg) by injection used at least twice, is effective in kennel situations (not licensed for use in dogs).
Toxic in Collies and Collie crosses.
- Fipronil Fipronil (topical application in ears once) - unlicensed use in dogs.
- Selamectin Selamectin , 1x month, is an effective treatment for ear mites - unlicensed use in dogs.
Control via environment
- The relevant importance of mites in the environment is unknown. Repeated treatment of the dog 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 dog sleeps with acaricide.
Other countermeasures
- In persistent cases it may be useful to treat the whole body with amitraz bath or lime sulfur dip.
Diagnosis
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Further Reading
Publications
Refereed papers
- Recent references from VetMedResource and PubMed.
- Chickering W R (1988) Cytologic evaluation of otic exudates. Vet Clin North Am Small Anim Pract 18(4), 773-782.
- 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.