Leporacarus gibbus Fur Mite Infection in Lagomorphs

Disease Summary

Alternative Names (Synonyms)

• Listrophorus gibbus infection
• Fur mite infection

See also: 

• Cheyletiellosis
• Other mite infections in lagomorphs:
  • Chiggers (Trombiculiasis) (In Waterfowl, Hedgehogs and Bears and Lagomorphs)
  • Demodicosis (with special reference to Hedgehogs, Bears and Lagomorphs)
  • Notoedres Mange in Hedgehogs and Lagomorphs
  • Psorobia lagomorphae Mite Infection in Lagomorphs
  • Psoroptes cuniculi Ear Mite Infection in Lagomorphs
  • Red Fowl Mite Infection in Lagomorphs
  • Sarcoptic mange

Disease Type

Infectious/Non-Infectious Agent associated with the Disease

• Leporacarus gibbus. 
• Formerly known as Listrophorus gibbus. (B600.9.w9, B601.13.w13, B602.19.w19, B606.4.w4)
• This mite was first reported as a parasite of wild Oryctolagus cuniculus - European rabbit in 1862 in Europe but is now known to infest wild and domestic rabbits around the world. (B614.11.w11, J213.4.w4)
• Listrophorus leporicolus on Lepus saxatilis - Scrub hare from Skukuza and Hluhluwe, South Africa. (J62.62.w4)

Infective "Taxa"

• Leporacarus gibbus (Listrophoridae)

Non-infective agents

Physical agents

References

Disease Author

Referees

Major References / Reviews

Code and Title List

Other References

Code and Title List

Detailed Clinical and Pathological Characteristics

• This is a non-burrowing fur mite, commonly described as non-pathogenic even if heavy infestations are present. (B601.13.w13, B604.5.w5)
  • "The presence of mites may not be associated with disease and they can be considered to be commensal ectoparasites". (B600.9.w9)
  • "Infestation is normally asymptomatic and is not significant except that large numbers can indicate some underlying disease". (B600.16.w16)

• "Leporacarus is described as a "non-pathogenic" parasite; however, the author is presented regularly with rabbits infested with Leporacarus with clinical signs of abnormal molt, hair loss, seborrhea, and dandruff". (J213.4.w4)

• Dermatitis is much more commonly associated with the other fur mite, Cheyletiella parasitovorax (Cheyletiellosis) than with Leporacarus gibbus. (B609.2.w2)

Clinical Characteristics

• Often asymptomatic. (J29.5.w1)
  • Presence of tiny dark specks on the fur can be the only sign. (J501.37.w2)
• Thinning of the hair in association with heavy infestations in wild rabbits. (J501.37.w2)
• A moist alopecic dermatitis which is sometimes pruritic. (B602.19.w19, B606.4.w4)
• Alopecia, seborrhoea and an abnormal moult. (B601.13.w13)
• The classic seborrhoea that is associated with Cheyletiellosis is not a feature of this condition. (B606.4.w4)
• Sometimes there may be scales and erythema. (B608.21.w21)
• Some rabbits have no skin lesions apart from pruritus and traumatic alopecia. (B608.21.w21)
• Distribution of lesions: 
  • The most common areas are the back, groin and the ventral abdomen. (B602.19.w19, B604.5.w5 B608.21.w21, B611.12.w12, J213.4.w4)
  • The mite may also be found anywhere on the rabbit. (J213.4.w4)
  • In one outbreak, mites were noted particularly to be present on the ventral surface of the tail. (J501.37.w2)

Incubation

• --

Mortality / Morbidity

• --

• "Skin lesions associated with mange mites are uncommon in free-living lagomorphs". (B284.10.w10)
• "Disease caused by rabbit fur mites, Cheyletiella sp. and Leporacarus gibbus, is the most common rabbit skin disease in the author's practice, present on more than 15% of the rabbits seen". (J213.4.w4)

Pathology

Human Health Considerations

• This is not a zoonotic disease. (B601.13.w13, B604.5.w5)
• Human infestation is possible but unusual and only occurs when the mite is very hungry. (J15.29.w1)

Disease has been reported in either the wild or in captivity in:

• Wild and domestic Oryctolagus cuniculus, and Lepus spp. (J501.37.w2)
• Listrophorus leporicolus on Lepus saxatilis - Scrub hare from Skukuza and Hluhluwe, South Africa. (J62.62.w4)
• Lepus timidus - Mountain hare. (J469.495.w1)

Further information on Host species has only been incorporated for species groups for which a full Wildpro "Health and Management" module has been completed (i.e. for which a comprehensive literature review has been undertaken). Host species with further information available are listed below:

Host Species List

• Lepus saxatilis - Scrub hare
• Lepus timidus - Mountain hare
• Oryctolagus cuniculus - European rabbit
• Oryctolagus cuniculus domesticus - Domestic European rabbit

(List does not contain all other species groups affected by this disease)

Disease has been specifically reported in Free-ranging populations of:

• Wild Oryctolagus cuniculus in Europe and Lepus spp. in North America. (J501.37.w2)
• Listrophorus leporicolus on Lepus saxatilis - Scrub hare from Skukuza and Hluhluwe, South Africa. (J62.62.w4)
• Lepus timidus - Mountain hare. (J469.495.w1)

Further information on Host species has only been incorporated for species groups for which a full Wildpro "Health and Management" module has been completed (i.e. for which a comprehensive literature review has been undertaken). Host species with further information available are listed below:

Host Species List

• Lepus saxatilis - Scrub hare
• Lepus timidus - Mountain hare
• Oryctolagus cuniculus - European rabbit

(List does not contain all other species groups affected by this disease)

General Information on Environmental Factors/Events and Seasonality

Regions / Countries where the Infectious Agent or Disease has been recorded

• North America, the British Isles, mainland Europe, Puerto Rico, India, New Zealand and Australia. (B614.11.w11, J501.37.w2)
• Listrophorus leporicolus in South Africa. (J62.62.w4)

Regions / Countries where the Infectious Agent or Disease has been recorded in Free-ranging populations

• Europe and North America. (J501.37.w2)
• Listrophorus leporicolus in South Africa. (J62.62.w4)

General Information on Investigation / Diagnosis

• Diagnosis is by the same methods as for Cheyletiellosis. (B602.19.w19)

• Note: It is not unusual to find both Leporacarus and Cheyletiella spp. on the same rabbit. (J213.4.w4)
• Clinical examination: Mites may be visible as dark specs on the fur, particularly on white rabbits. (J501.37.w2)
  • A thorough general examination should be carried out to rule out underlying causes or reduced grooming.
• Hair pluck: Hairs plucked from two locations where mites are visible. If mites are not visible on visual inspection of the rabbit, then pluck hair from several locations, but particularly the ventral aspect of the tail. (J501.37.w2)
  • Place the hairs on a glass slide with a little mineral oil (to keep the samples on the slide and allow a cover slip t be applied) and examine at 40X to 100X magnification. (J501.37.w2) 

• Skin biopsy with histological examination: can be used to rule out Sebaceous adenitis. 

• Imaging: dental or spinal radiographs to rule out any underlying musculoskeletal or dental disease. 
  (B609.2.w2)

• Examination of epidermal debris
  • See Clinical Pathology of Lagomorphs - Skin Testing
  • Collect samples by using a flea comb, brush, acetate tape, or skin scrape. (B602.19.w19, B609.2.w2, B611.12.w12)
  • Examine under a dissecting microscope. (B611.12.w12)
  • Identification
    • This mite is is usually seen moving along hair shafts where it feeds on secretions from sebaceous glands and epithelial scales. (B600.16.w16, J213.4.w4)
    • It has special legs which area adapted to cling to the hair shaft. (B600.9.w9)
    • Mites: 
      • Leporacarus gibbus mites can be seen by the naked eye (especially on light-coloured rabbits) and they usually move away from direct light. (B600.9.w9)
      • They are laterally compressed, brown mites (due to dense chitin) with short legs and a single projection extending from the head over the mouth parts. (B602.19.w19, J213.4.w4)
      • "The head is sclerotised, giving it a dark appearance". (B606.4.w4)
      • The legs do not have clasping adaptations, instead they attach to the hair via membranous flaps that arise from the first pair of legs' coxae. (B606.4.w4)
      • There is sexual dimorphism. (B600.9.w9):
        • Female: large oval mite with a thumb print pattern over the body (B600.9.w9) (the cuticle is finely striated). An adult female has a similar shape to a flea. (B606.4.w4) 310 x 560 µm (B611.12.w12) µ
        • Male: slightly smaller mite (240 x 440 µm (B611.12.w12) and it has two long adanal processes plus distinct adanal suckers (B600.9.w9) "powerful appearing clasping organs located at their posterior end." (B611.12.w12)
    • Ova: 
      • Ova are attached to the hair shafts as in Cheyletiellosis, however, in Leporacarus, the eggs are more distal on the hair shaft and have a looser attachment. (B602.19.w19) 
        • The eggs are smaller than those of Cheyletiella spp. (J213.4.w4)
      • Hatched eggs may be seen attached to the shafts of hairs similar to that of louse eggs. The egg seems to split down the midline dorsally during the larval emergence. This gives the egg cases two wing-like structures. These empty cuticles can persist on hairs after moulting has occurred and this gives the fur a characteristic appearance of "salt and pepper" - this is more obvious if the coat is wet. The cuticles may persist after the mites have been treated and killed. In contrast, dead mites of a Cheyletiellosis infection soon disappear from the host after treatment. (B600.9.w9, B600.16.w16)

• Environmental Assessment
• History & Documentation
• Physical Examination of Mammals
• Necropsy of Mammals
• Imaging in Lagomorph Diagnosis and Treatment
• Clinical Pathology of Lagomorphs
• Treatment and Care
• Environmental and Population Management
• Preventative Medicine for Mammals
• Chapter 2 - B36 Field Manual of Wildlife Diseases - Specimen Collection and Preservation
• Chapter 3 - B36 Field Manual of Wildlife Diseases - Specimen shipment
• Appendix A - B36 Field Manual of Wildlife Diseases - Sample specimen history form

Similar Diseases (Differential Diagnosis)

• Other fur mites: 
  • Cheyletiella species.
  • Mite infection may be concurrent with a flea infestation.
  • Distribution: Lesions around the tail base or intrascapular region.
  • Clinical signs: Profuse amounts of  large, white scale.
  • Diagnosis: Skin scrapes or acetate tape preparations- easy to see mites under low magnification.
   
• Ear mites:
  • Psoroptes cuniculi
  • Usually very pruritic.
  • Distribution: The inside of the pinnae, the surrounding ears, face, and the neck.
  • Clinical signs: Chronic infection- skin thickening, and exudative crusts.
  • Diagnosis: Mites visible with the unaided eye or may see them under low magnification.
    
• Flea hypersensitivity dermatitis: (Flea Infection in Mammals).
  • Clinical signs: patchy alopecia and pruritus. Sometimes see a secondary pyoderma.
  • Diagnosis: fleas or flea dirt found in coat.
    
• Other parasites:
  • Sarcoptic Mange: Sarcoptes scabiei and Notoedres Mange: Notoedres cati
    • Both are rare in the rabbit
    • Distribution: head and neck.
    • Clinical signs: very pruritic lesions.
      
• Bacterial Dermatitis in Lagomorphs
  

• Lack of grooming:

  • Caused by obesity or an underlying musculoskeletal or dental disease.
  • Clinical signs: scale accumulation.
    

• Injection Reactions In Rabbits:

  • Occurs particularly with irritating substances, e.g. enrofloxacin.
  • Distribution: intrascapular area is the common area for subcutaneous injections.
  • Clinical signs: alopecia and crusting.
    
• Sebaceous adenitis in Rabbits:
  • Distribution: often starts around the head and neck.
  • Clinical signs: copious amounts of white flakes and scale. Alopecia. Usually not pruritic.
  • Diagnosis: skin biopsy and histological examination .

(B609.2.w2)

Specific Medical Treatment

• Treatment involves killing the mite, removing scale and treatment of any underlying grooming difficulties. (B600.9.w9)

Drugs of choice:

• Ivermectin 
  • Treatment of choice. (B601.13.w13, B608.21.w21)
  • Usually effective. (B609.2.w2)
  • Effective treatment (B615.6.w6)
  • 0.4 mg/kg by subcutaneous injection every 10-14 days for three doses. (B601.13.w13, B602.19.w19, B606.4.w4, B609.2.w2)
  • Effective in killing the mites. A second dose is necessary 10-14 days after the first. (B600.9.w9)
  • Not licensed for use in rabbits but no adverse reactions have been reported. (B609.2.w2)
  • "Treatment with ivermectin reduces the population of Cheyletiella spp. mites; however, the infestation has not been eradicated in many cases treated at the author's practice". (J213.4.w4)
• Selamectin 
  • A very effective treatment for this condition; a single dose seems to last long enough to eliminate all stages of the life cycle. Routine administration is recommended for rabbits that cannot groom themselves properly. (P601.1.w1)
  • 6-18 mg/kg applied topically once only. Single application seems to be effective. (B600.4.w4, B601.15.w15)
  • 6-12 mg/kg applied topically. Repeat in 2-4 weeks if necessary. (B609.2.w2)
  • In a study of 23 rabbits with cheyletiellosis, a single dose of topical selamectin at 12 mg/kg was proved to be effective in the treatment of this disease. At five weeks post treatment, all of the rabbits were negative for mites and eggs. (J476.19.w1) 
  • Not licensed for use in rabbits but no adverse reactions have been reported. (B609.2.w2)
• Imidacloprid and moxidectin
  • Imidacloprid plus moxidectin at a dosage of 10 mg/kg and 1 mg/kg respectively, percutaneously every four weeks for three treatments. (P600.1.w1)

Other Medications:

• Carbaryl powder (5%) (Carbamates)
  • Apply by sprinkling down each side of the rabbit's back from the occipital protruberance to the tail and all over the tail, and rub gently into the fur. (J501.37.w2)
  • A single application is not necessarily effective:
    • Re-examine the rabbit after 5 - 7 days; a second application of the acaricide may be required. (J501.37.w2)
    • Apply as a topical treatment once a week. (B609.2.w2)
    • Use powder that is appropriate for cats, twice a week for six weeks. (B602.19.w19)
  • May also be used to treat the environment. (B609.2.w2)
  • Note: Successful when used repeatedly but there have been reports of toxicity problems. (J213.4.w4)
• Lime sulphur rinses - see Bathing Rabbits
  • These have also been effective but are reportedly difficult to use in rabbits - see "precautions" below. (B609.2.w2)
  • Use once weekly for 3-6  weeks. (B 602.19.w19)
  • "good success with 3 to 4 weekly dips". (J213.4.w4)
• 0.01% Amitraz - see Bathing Rabbits
  • Amitraz must be diluted 1:500 to achieve this concentration. Dipping is necessary once a week for up to six weeks. (B606.4.w4)
• Permethrin powder
  • Cheyletiella can be reduced by dusting the adult rabbits, weanlings and the bedding at weekly intervals. (B604.5.w5)

Reinfestation:

• Investigate if the animal has contact with an asymptomatic carrier or if there is an unidentified source of mites, for example, untreated bedding. (B609.2.w2)

Contraindications:

• Do not use on rabbits: Fipronil, flea collars, products containing Organophosphates.(B609.2.w2)
• Dog and cat topical flea preparations. (B609.2.w2)

Precautions:

• Dipping or bathing rabbits (Bathing Rabbits): high risk of skeletal fractures or excessive chilling if performed by inexperienced people. "Sudden death has also been reported during or after bathing rabbits."
• Off-label use of medication: most flea control products are not licensed for use in rabbits and therefore their efficacy and safety have not been evaluated in this species. Use with caution particularly in debilitated or young animals.
• Licking of topical spot-on products: must prevent the animal or its cage mate from doing this before the product has had chance to dry. 
• Adverse reactions to pyrethrins and pyrethroid-type flea products: clinical signs include hypersalivation, muscle tremors, ataxia, depression, anorexia, and dyspnoea [if a very large excess dose is given]. (See: Permethrin and Pyrethrin Toxicity in Rabbits)
• Toxicity: If signs of toxicity are shown, the rabbit must be bathed thoroughly to remove remaining chemicals and have appropriate treatment.

(B609.2.w2)

• Treatment and Care

General Nursing and Surgical Techniques

• Daily combing to remove scale- this removes the keratin that the mites feed on. Use a fine toothed flea comb. (B600.9.w9, B609.2.w2)
• Bathing may also be effective at removing scale but is usually difficult with rabbits- see "precautions" in the treatment section above. (B609.2.w2)
  • Some authors recommend bathing the animal in selenium sulphide shampoo, which has no insecticidal properties but will remove the keratin that mites feed on. (B600.9.w9)
  • 1% selenium sulphide shampoo is beneficial for seborrhoea. The rabbit should be dried using a hair-dryer, and not towelled. (B606.4.w4)

• Treatment and Care

Preventative Measures

--

• Routine administration of selamectin is recommended for rabbits that cannot groom themselves properly. (P601.1.w1)

For colony rabbits:

• New arrivals, unless they are known to be free of mites, should ideally be quarantined and given two doses of ivermectin with a 14 day interval before entering an established clean colony. (B604.5.w5) 

• Preventative Medicine for Mammals

Environmental and Population Control Measures

Lagomorphs

• Disinfect the environment by using flea products (i.e. carbaryl 5% dust). (B602.19.w19)
• Spray the hutch with an environmental flea product, e.g. Vet-Kem Acclaim Plus (Sanfoni Animal Health Ltd.) which contains 0.58% permethrin and 0.09% w/w S-methoprene. (B606.4.w4)
• Remove and discard all the organic material from the cage (paper or wood products, bedding). (B609.2.w2)
  • Replace the bedding with shredded paper bedding and discard this daily along with thoroughly daily cleaning of the cage during the treatment period. (B609.2.w2)
• Discard or thoroughly disinfect any grooming utensils before reuse. (B609.2.w2)

• Environmental and Population Management - General