Mites

Mites that can infest rabbits range from fur mites and ear mites to burrowing mites that cause mange.

Ear mites
Ear mite infestations in rabbits are caused by the parasite Psoroptes cuniculi. They can affect only one ear or both, and symptoms may spread to the rest of the body such as the perineal skin folds.

These mites are large and active and are just visible to the naked eyes. They are surface dwellers that cause intense irritation when present in large numbers. :442

Symptoms

 * Crusting and ulceration of the external ear canal.

Extra resources

 * PetMD, Infestation of Mites in the Ear in Rabbits
 * Phyllis O'Beollain, Ear mites in rabbits
 * Clinician’s Brief, Online Gallery: A Close-Up on Ear Mites

Fur mites
Fur mites that infest a rabbit are most commonly Cheyletiella spp. and less commonly Leporacarus gibbus (formerly known as Listrophorus gibbus).

The highly contagious Cheyletiella spp. mites are zoonotic and can also live on cats and dogs. These mites can temporarily infest humans when they pet or hold an infested rabbit and cause skin irritation and itching. They are a non-burrowing mite and live on the surface skin layer. Fur mites are often referred to as "walking dandruff" due to the large mite size that cause them to be visible to the naked eye. and excessive flaking of the skin.

The life cycle of Cheyletiella spp. mites is approximately 35 days of which the entirety are spent on the host. Most rabbits do not show symptoms of a fur mite infestation; the disease occurs in young animals, debilitated animals, or those with underlying diseases that prohibit adequate grooming. In a survey of 220 laboratory rabbits, 43.2% had inapparent C. parasitovorax infestations.

Infestations of the rabbit fur mite L. gibbus are usually asymptomatic, although hypersensitivity reactions have been reported. :442 These mites inhabit the fur, can be seen with the naked eye especially on light-colored rabbits, and tend to move away from direct light. An infestation usually gives the coat the appearance of being sprinkled with pepper, especially when wet. :442

Symptoms

 * Loss or thinning of hair along the shoulders and middle back of the rabbit.
 * Dandruff-like flakiness.
 * Itching.

If you have sensitive skin, you may also experience some skin irritation when in contact with a rabbit with fur mites. Lesions are usually found on the forearms and neck.

Causes
Fur mites can be found in any age of rabbit but is most common in young animals, debilitated animals, or those with underlying diseases that prohibit adequate grooming. They may also be more common in long-haired rabbits. Infestation with fur mites is often associated with obesity, spinal disorders, or dental disease. :442

The inability to groom the rear end or tail base region can contribute to the start of irritation in these areas. A common source of fur mites are pet stores, shelters, and breeders.

Diagnosis
The veterinarian can obtain skin scrapings and sometimes see the mites under a microscope, but not always.

Diseases that can show similar symptoms include ear mite (Psoroptes cuniculi) infestation, mange (rare), flea hypersensitivity dermatitis, ringworm, and bacterial dermatitis.

In some rabbits, the lack of grooming alone can cause an accumulation of flakes without the presences of mites.

Treatment
There are several drug treatments available for rabbits with fur mites.
 * Selamectin [Revolution® (US) or Stronghold® (Europe) - Pfizer] once every three to four weeks for two to three treatments.
 * Ivermectin (topical, oral, subcutaneous) once every 10 to 14 days for two to four treatments.
 * Do not use fipronil [Frontline® - Merial]. Fipronil is effective in eliminating Cheyletiella sp., however, serious adverse effects such as depression, anorexia, seizures, and death have been observed in rabbits, especially young and small ones.
 * Advantage® is not effective against fur mites.
 * Carbaryl powder (5%) can be applied topically once weekly and can also be used to treat the environment.

Additional treatment includes the following:
 * All animals in the household should be treated including cats and dogs.
 * Rabbits should be combed daily to remove skin flakes.
 * Bathing and lime-sulfur rinses can be effective in removing skin flakes but is dangerous to perform on rabbits due to their thick dense fur, restraint, and risk of both overheating and chilling.
 * The environment should also be treated and regularly cleaned to eliminate the infestation as eggs and adult female mites can live up to 10 days off of a host. Larvae, nymphs, and adult males are less resitant and die in about 2 days in the environment. Remove and discard all organic material such as wood and paper products, and replace litter daily during the treatment period.
 * Combs, brushes, and grooming utensils should be replaced or thoroughly disinfected before re-use.

Treatment failure necessitates reevaluation for other causes of symptoms. Reinfestation may indicate contact with an asymptomatic carrier or the presence of an unidentified source of mites (e.g. untreated bedding).

Extra resources

 * MediRabbit, Esther van Praag Ph.D., Common Fur Mites or Cheyletiellosis
 * Angie Pollock, Treatment for fur mites in rabbits
 * Drs. Foster & Smith, Cheyletiella parasitovorax (Rabbit Fur Mite)
 * BunSpace, Fur Mites- Treating the Bun and Its Living Environment

Harvest mites
Harvest mites Neotrombicula autumnalis can infest rabbits that have access to outdoor habitats where harvest mites are found. Adult mites lay their eggs in the soil, and the larvae on hatching move onto low vegetation to await a host. Larvae can survive up to 30 days without a host.

In rabbits, the larvae are most commonly found on the ears, anus, the corners of the eyes, and feet. Their feeding process causes severe skin flaking and the formation of bumps and discoloration on the skin. Treatment is difficult, but the disease is seasonal and self-limiting. Removing the rabbit from the infested area prevents further reoccurrences.

Demodex cuniculi
Although not common, Demodex cuniculi has been found in skin scrapings from rabbits in the UK. The mite can live on the skin of normal rabbits in the abscence of associated clinical signs.

Psorobia lagomorphae
A new subspecies of Psorergatid mites recently identified causes mild flaking in rabbits. There are no published reports regarding treatment.