Demodicosis (with special reference to Hedgehogs, Bears and Lagomorphs) 

Disease Summary

Lagomorphs:

• In the UK, Demodex cuniculi has been identified in skin scrapes taken from rabbits. It can occur in rabbits without any associated clinical signs. (B600.9.w9, B602.19.w19)
• This mite may cause dermatitis in immunosuppressed rabbits that are subjected to other diseases or to environmental stress. (B602.19.w19)
• Isolation of Demodex from rabbits with generalised pruritus and scaling has been reported. However, the pathogenic significance of Demodex in these cases is in doubt. (B601.13.w13, B608.21.w21)
• Affected rabbits may show variable levels of pruritus. (B601.13.w13, B610.23.w23)

Alternative Names (Synonyms)

See also other mite infections: 

• Audycoptic Mange in Bears 
• Caparinia Mange in Hedgehogs
• Cheyletiellosis
• Chorioptic Mange in Hedgehogs and Bears
• Leporacarus gibbus Fur Mite Infection in Lagomorphs
• Notoedres Mange in Hedgehogs and Lagomorphs
• Otodectes cynotis Ear Mite Infection in Hedgehogs
• 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

• Mange mite - Demodex erinacei (J15.21.w1, J18.38.w1); in the sebaceous gland of the hair follicles. (B291.12.w12)

In Bears

• Demodex ursi (J1.34.w10, J426.21.w1)

In Lagomorphs

• Demodex cuniculi (B600.9.w9, B601.13.w13,  B602.19.w19,  B608.21.w21)
  • This mite inhabits the epidermis and hair follicles of the rabbit's skin. (B602.19.w19)

Infective "Taxa"

• Demodicidae (Family)

Non-infective agents

Physical agents

References

Disease Author

Referees

Major References / Reviews

Code and Title List

Hedgehogs
B291.12.w12, J15.21.w1, J18.38.w1

Bears
J1.14.w9, J1.29.w13, J1.34.w10, J426.21.w1
D315.3.w3

Lagomorphs
B600.9.w9, B601.13.w13, B602.19.w19, B604.5.w5, B606.4.w4, B608.21.w21, B610.23.w23, J29.5.w1, J213.4.w4

Other References

Code and Title List

Detailed Clinical and Pathological Characteristics

Clinical Characteristics

Infections are generally asymptomatic. Symptomatic forms are seen most commonly in the dog and include:

• Localised lesions: slight hair loss and skin thickening on the face and forelimbs.
• Squamous generalised demodecosis: widespread alopecia and desquamation and thickening of the skin, with little erythema,.
• Pustular (follicular) generalised demodecosis: more severe, associated with secondary bacterial infection. Wrinkled and thickened skin, with large numbers of small pustules oozing serum, pus and blood, and with a characteristic offensive odour. 

(B46)

• Erythema and alopecia, particularly of the head, but without pruritus. (B22.32.w15)

• Raised papules.
• Crusty skin lesions and flaking scales

• In a female Ursus americanus - American black bear from northern Wisconsin, partial alopecia and scabs. (J1.14.w9)
  • Five of 70 live-trapped bears were noted to have "mange" but no mites were found. (J1.14.w9)
• Pruritis, localised alopecia, thickening and crusting of the skin may occur. (D315.3.w3)

In Ursus americanus - American black bear in Florida:

• Alopecia of varying degrees, sometimes scaly skin. (J1.29.w13)
  • In a five-year-old adult male, severe alopecia except on the dorsal neck, ears and paws, and the skin was grey, smooth, mildly scaly and on the head and forelimbs rougher, with more scales. (J1.29.w13)
  • In a seven-year-old female, on the chest, legs and head there were extensive areas of alopecia. (J1.29.w13)
  • In a yearling female the forearms showed mild alopecia. (J1.29.w13)
  • In a 10 to 11-month-old male and a four-year-old male, the chest and face showed mild to moderate hair loss. (J1.29.w13)
  • In two 10-month-old cubs and one adult, mild alopecia and crusty, scaly skin. (J1.34.w10)
  • In one 10-month-old cub, crusty, scaly skin and mild alopecia. On the crown and wrist was a crusty, yellowish exudate, possibly due to secondary pyoderma. (J1.34.w10)
• In a cub with demodicosis and trombiculiasis [Chiggers (Trombiculiasis) (In Waterfowl, Hedgehogs and Bears)], scaling and crusting were present over the whole body, particularly ventral areas. (J1.37.w8)

• Demodex mites are not thought to be associated with disease in the rabbit. (J29.5.w1, J213.4.w4)
• Affected rabbits may show variable levels of pruritus. (B601.13.w13, B610.23.w23)
• Generalised pruritus and scaling. (B601.13.w13, B608.21.w21)
• A moist erythematous dermatitis with small (2-4 mm in diameter) pustules. This condition is not pruritic. (B606.4.w4)

Incubation

Mortality / Morbidity

• --

• Demodex erinacei may be found in the hair follicles of hedgehogs (J18.38.w1, B258)
• Demodectic mange has been reported in British hedgehogs Erinaceus europaeus - West European Hedgehog. (B259.w7, B228.9.w9) 

• Uncommon. Demodicosis has been reported only in Ursus americanus - American black bear. 
  • Clinical demodicosis has been reported in nine individuals of more than 460 carcasses examined in Florida; no mites were detected in 750 skin scrapings from 51 other bears (without skin lesions) in one study in which four of the clinical cases were detected. (J1.34.w10)
  • Clinical demodicosis (partial alopecia) was detected in one individual from northern Wisconsin.  (J1.14.w9)

• The pathogenic significance of Demodex is in doubt. (B601.13.w13, B608.21.w21)
• This mite is occasionally seen on skin scrapings. However, they are not thought to be associated with disease. (J213.4.w4)

Pathology

• These mites may be found within the sebaceous glands. (J15.21.w1)

Gross:

• Skin: alopecia, smooth, mildly scaly skin; some areas rougher and more scaly. (J1.29.w13)

Histopathology:

• Skin: 
  • "moderate orthokeratotic hyperkeratosis, and mild to moderate follicular hyperkeratosis." (J1.29.w13)
  • Hairs mainly in telogen and catagen. (J1.29.w13)
  • Mild acanthosis on the forearms. (J1.29.w13)
  • Rarely, superficial dermatitis and follicular pustules. (J1.29.w13)
  • Presence of Demodex sp. mites within hair follicles (more than 20 in a single cross section of some follicles), and at the infundibulum of sebaceous glands. Follicles with mites present generally did not have hair present and did have varying follicular hyperplasia and plugging of the follicle. (J1.29.w13)

In a Ursus americanus - American black bear cub with demodicosis and trombiculiasis:

• Skin: Follicles containing Demodex mites were noted to show "follicular hyperkeratosis with a diffuse, sometimes nodular, perifollicular and dermal infiltrate composed of lymphocytes, plasma cells, mast cells, neutrophils, eosinophils, and histiocytes." (J1.37.w8)

Human Health Considerations

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

• Demodectic mange has been reported in British hedgehogs Erinaceus europaeus - West European Hedgehog. (B259.w7, B228.9.w9) 
• A female Ursus americanus - American black bear with alopecia and scabs, from northern Wisconsin. (J1.14.w9)
• In five Ursus americanus - American black bears with alopecia, from Florida. (J1.29.w13)
• In four Ursus americanus - American black bears with alopecia and skin scaling, from Florida. (J1.34.w10)
• In one Ursus americanus - American black bear cub, in association with trombiculiasis (see: Chiggers (Trombiculiasis). (J1.37.w8)
• In one yearling Ursus americanus - American black bear from central Florida, which also had agenesis of the right kidney. (P2.48.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

• Erinaceus europaeus - West European Hedgehog
• Ursus americanus - American black bear
• 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:

• A female Ursus americanus - American black bear with alopecia and scabs, from northern Wisconsin. (J1.14.w9)
• In five Ursus americanus - American black bears with alopecia, from Florida. (J1.29.w13)
• In four Ursus americanus - American black bears with alopecia and skin scaling, from Florida. (J1.34.w10)
• In one Ursus americanus - American black bear cub, in association with trombiculiasis (see: Chiggers (Trombiculiasis). (J1.37.w8)

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

• Ursus americanus - American black bear

(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

• In Florida and Wisconsin, USA. (J1.14.w9, J1.29.w13, J1.34.w10, J1.37.w8)

In lagomorphs:

• UK and North America. (B600.9.w9, B601.13.w13, B602.19.w19, B608.21.w21, B610.23.w23)

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

• --

General Information on Investigation / Diagnosis

• Deep skin scrapings are required for diagnosis. (J15.21.w1)

• Skin scrapings. (J1.29.w13, D315.3.w3)
  • Squeeze the skin before taking deep skin scrapings, to ensure that Demodex mites are extruded from the hair follicles. (D315.3.w3)
• Examination (at 100 X magnification) of deep skin scrapings from multiple sites on the head (lower nose, upper nose between the eyes, forehead, crown, upper eyelids, lower eyelids, upper lip (both sides), caudal pinna) and front legs (base of the middle digit, wrist, middle of the forearm). (J1.34.w10)
• Examination of skin samples digested in 10% potassium hydroxide (KOH). (J1.34.w10)

• Skin scraping and microscopy: several scrapings may be necessary to detect Demodex cuniculi . Under microscopy it is identified as a long thin mite that is similar to the canine Demodex mite. (B606.4.w4)

• Environmental Assessment
• History & Documentation
• Physical Examination of Mammals
• Necropsy of Mammals
• Clinical Pathology of Lagomorphs
• 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 mite infections: 

• Caparinia Mange in Hedgehogs
• Chorioptic Mange in Hedgehogs
• Notoedres Mange in Hedgehogs
• Otodectes cynotis Ear Mite Infection in Hedgehogs
• Sarcoptic mange

• Audycoptic Mange in Bears (Parasitic Disease)
• Chiggers (Trombiculiasis) (In Waterfowl, Hedgehogs and Bears) (Parasitic Disease)
• Sarcoptic Mange (Parasitic Disease)

• Cheyletiellosis
• Chiggers (Trombiculiasis) (In Waterfowl, Hedgehogs and Bears and Lagomorphs)
• Leporacarus gibbus Fur Mite Infection in Lagomorphs
• Psorobia lagomorphae Infection
• Psoroptes cuniculi- Ear Mite Infection in Lagomorphs
• Red Fowl Mite Infection In Rabbits
• Sarcoptic Mange

Specific Medical Treatment

• Ivermectin (Ivomec, Merial Animal Health, 3 mg/kg subcutaneously) (J15.21.w1)
  • 0.2-0.3 mg/kg by subcutaneous injection. (B284.6.w6)
• Amitraz washes may be used (1:400 dilution applied to the skin every three days). (B284.6.w6)
• Note: The cage must be cleaned out thoroughly and the bedding changed during treatment. (B284.6.w6)

• No treatment given; clinical demodicosis has been detected only in dead free-living bears. (J1.34.w10)
• Ivermectin could be used, or appropriate topical sprays/dips etc. as used in dogs. (D315.3.w3)

• Ivermectin by weekly subcutaneous injection. It may be necessary to use a dose of 0.5 mg/kg to effect a cure. 
• 0.01% solution of Amitraz, (dilute 1:500 with water)
  • The affected rabbit needs to be bathed weekly in this solution. 
  • This treatment may be used as an alternative to ivermectin. 

(B606.4.w4)

• Treatment and Care
• Subcutaneous Injection of Hedgehogs
• Subcutaneous Injection of Mammals

General Nursing and Surgical Techniques

• Treatment and Care

Preventative Measures

--

• Preventative Medicine for Mammals

Environmental and Population Control Measures

HEDGEHOGS

• Note: The cage must be cleaned out thoroughly and the bedding changed during treatment. (B284.6.w6)

• Quarantine newly-arrived bears. (D270.VII.w7)
• Bears should be checked for mite infections while in quarantine and any infection eliminated before they are translocated, reintroduced or introduced to a new enclosure or collection. (B407.w18, B433)

• Environmental and Population Management - General