Ringworm in Hedgehogs, Bears, Lagomorphs and Ferrets (with notes on Elephants):

Disease Summary

Ringworm is an uncommon disease of lagomorphs; it has been reported in both domestic rabbits and wild lagomorphs.

• In rabbits: an uncommon fungal skin disease that is more likely to be seen in young or debilitated animals. The fungal infection can affect the keratinised layer of nails, hair and occasionally the skin's superficial layers. Rabbits can be asymptomatic carriers.

Alternative Names (Synonyms)

• Dermatophytosis (J213.4.w4)
• Flavus (B10.45.w47)
• Dermatomycosis (J213.4.w4)

Disease Type

Infectious/Non-Infectious Agent associated with the Disease

IN HEDGEHOGS

• Trichophyton erinacei in hedgehogs (J3.128.w2, J60.1.w1, B151, B337.3.w3)
• Trichophyton mentagrophytes var. erinacei (J152..3.w1, J15.21.w1, J18.38.w1, B22.27.w3, P17.24.w4) In culture, distinguished by the production of a yellow pigment. (P17.24.w4)
• Microsporum spp. occasionally. (B22.27.w3)
• Trichophyton mentagrophytes (Trichophyton mentagrophytes var. granulare) (J18.38.w1)
• Trichophyton schoenleinii. (J18.38.w1)
• Trichophyton terrestre (apparently non-pathogenic). (J18.38.w1, J152.2.w1)
• Microsporum cookei. (J18.38.w1)

May be secondary to mange, to scratch wounds or to Staphylococcus aureus dermatitis (Staphylococcosis). (B22.27.w3)

IN BEARS

• Microsporum canis reported in Helarctos malayanus - Sun bears. (J4.155.w5, B16.9.w9)
• Trichophyton spp. in Ursus americanus - American black bear. (J417.20.w1)

IN LAGOMORPHS

Commonest organisms reported:

• Trichophyton mentagrophytes (B600.9.w9, B609.2.w2) 
  • This is the most common dermatophyte isolated in domestic rabbits (B602.19.w19, B604.5.w5, B608.21.w21) and in wild lagomorphs. (B614.15.w15)
  • This fungus is more common in laboratory and outdoor rabbits. (B601.13.w13, B610.23.w23, J213.4.w4)
  • There are several cultural variants of this fungus. (B604.5.w5)
  • Identification of culture: 
    • Macroscopically: Flat, white to grey powdery colony that has a brown underside. (J213.6.w1)
    • Microscopically: Cigar shaped macroconidia with thin walls; spiral hyphae and grape-like microconidia. (J213.6.w1)
• Microsporum canis (B600.9.w9, B608.21.w21, B609.2.w2, B614.15.w15, J495.32.w7) 
  • This fungus is more common in house and pet rabbits. (B601.13.w13, B610.23.w23, J213.4.w4, J213.6.w1)
  • Identification of culture: 
    • Macroscopically: Whitish, cotton-like colony that has a yellow orange underside. (J213.6.w1)
    • Microscopically: Spindle shaped macroconidia with knob-like ends and thick walls. (J213.6.w1)
• Microsporum gypseum (B600.9.w9, B608.21.w21, B609.2.w2, B614.15.w15) 
  • This fungus is more common in house and pet rabbits. (B601.13.w13, B610.23.w23, J213.4.w4, J213.6.w1)
    • Identification of culture: 
      • Macroscopically: Flat, pale brown colony that has a pale yellow underside. (J213.6.w1)
      • Microscopically: Spindle shaped macroconidia with no knob-like ends and thin walls. (J213.6.w1)

Other organisms reported:

• Microsporum audouinii
• Microsporum cookei 
  • This fungus has been reported in wild lagomorphs [species not specified]. (B614.15.w15)
• Trychophyton schoenleinii 
• Trychophyton verrucosum

(B600.9.w9, B608.21.w21, B614.15.w15)

Note: Microsporum audouinii and Trychophyton schoenleinii are "now thought to be exclusively anthropophilic dermatophytes...and the previous reports of these infections in rabbits were most likely due to misidentification". (B614.15.w15)

IN FERRETS

• Mycosporum canis and Trychophyton mentagrophytes, as in dogs and cats. (B626.8.w8, J213.6.w3)
  • In an outbreak in kits in a ferret colony, Microsporum canis was isolated. (J196.67.w1)
• Mycosporum canis has been isolated from ferrets in New Zealand; all eight isolates over a period of 20 years were this fungus. (J195.24.w2)

Infective "Taxa"

• Microsporum (Fungal Genera)
• Trichophyton (Fungal Genera)

Non-infective agents

Physical agents

References

Disease Author

Referees

Major References / Reviews

Code and Title List

In Elephants:
P501.1.w2

In Bears:
B10.48.w43, B16.9.w9, B64.26.w5, B336.51.w51, B407.w18 
J4.155.w5, J417.20.w1
V.w93

In Lagomorphs:
B10.45.w47, B64.22.w8, B336.42.w42, B600.9.w9, B600.16.w16, B601.13.w13, B602.18.w18, B602.19.w19, B604.5.w5, B606.4.w4, B609.2.w2, B610.23.w23, B614.15.w15, B615.6.w6
J3.146.w2, J15.29.w1, J213.4.w4, J213.6.w1

In Ferrets:
B626.8.w8, B627.17.w17, J195.24.w2, J213.6.w3, J196.67.w1

Other References

Code and Title List

Detailed Clinical and Pathological Characteristics

Clinical Characteristics

• Skin scaly and harsh; crusts may form. (B47)
• Hair brittle, appearing dry and lustreless. (B47)

• Often subclinical. (B156.7.w7, B284.6.w6)
• May present with generalised scale over the body with or without generalised spine loss, or scabs and scurf in focal areas along the border of the skirt at the spine/ hair margin or with facial and aural scale and alopecia. (V.w26, B228.9.w9)
• Dry white flaky skin. (B337.3.w3)
• Ears in chronically infected hedgehogs may be thickened, dry, and crusty, with crumbling margins. (B228.9.w9, B284.6.w6)
• Cracked crusty lesions, hair loss (particularly of the face and head, also other areas including the ventral surface); lesions bleed when scabs are removed. (B284.6.w6)
• Often with concurrent mite infection and bacterial infection (J15.21.w1); may be secondary to mange, scratch wounds or Staphylococcus aureus dermatitis (B22.27.w3)
• Characteristic crusts around spine base and flaky skin (J15.21.w1, B151, B22.27.w3, B284.6.w6).
• Spines in the area around the lesion may be loose and easily pull out. (V.w26)
• Spines may fall out. (B284.6.w6, B337.3.w3)
• "Lesions, when seen, mostly occur in the nose and ears as crusty scaling scabs." (P17.24.w4)
• Commonly raised scabby lesions mainly on the snout, and generally related to mixed infection with mites and/or Staphylococcosis. (J18.38.w1)
• Infection with Trichophyton terrestre is inapparent. (J152.2.w1)
• Lesions may affect the snout, ears, and sometimes the back. (J152.2.w2)
  • Lesions were scaly. (J152.2.w2)
  • One individual had a bald, scaly, raised patch, somewhat crusted and edged by an area which was partially depilated. (J152.2.w2)
  • Scaling on the ears may be white to yellowish and may form a horny mass on the ear. (J152.2.w2)
• Spread of disease from the head initially to the body later may take place over a period of time (several weeks to months). (J152.11.w1)
• The severity of infection may increase over time. (J152.11.w1)
• Neither regression of infection nor recovery was observed in several hedgehogs either maintained in captivity for a period of several weeks to months or observed repeatedly in the wild over a period of months. (J152.11.w1)
• Generally non-pruritic. (B284.6.w6)
• May gain weight normally and show little irritation even with severe infection. (B228.9.w9)
• May cause irritation such that the hedgehog scratches, excoriated the skin so that it bleeds, and bacterial infection may then develop. (B337.3.w3)

• Ringworm can affect the hair, also the nails. (B407.w18)
• Signs may include matting and crusting of the coat, or localised hair loss and skin inflammation anywhere on the body. (B407.w18)

In two Helarctos malayanus - Sun bears. (J4.155.w5) 

• On the ventral trunk, four lesions 1.0 - 8.0 cm diameter on one bears; on the other five lesions 1.0 - 3.5 cm diameter. Also on the second bear on the head, six small circular lesions. (J4.155.w5)
• Lesions involved moderate alopecia, scaling, but no erythema. (J4.155.w5)

• "Most animals that carry T.mentagrophytes have few or no clinical signs of infection". (B604.5.w5)
• Lesions usually begin with alopecia and scaly dry skin. 
  • Focal to multifocal alopecia
    • Hairless areas may be two to three centimetres in diameter.
    • In young rabbits the lesions are often more generalised than focal. 
  • Classic circular alopecia
    • The typical characteristic raised, red circular lesions of ringworm, with a clear centre, may be seen in rabbits but are an uncommon finding. 
  • Broken hairs
  • Papules (multiple) may be seen. (J495.32.w7)
  • Erythema, scales and yellow crust are variable and often occur in the more advanced cases. 
  • Pruritus is variable. It is unusual unless there is secondary bacterial infection. 
  • Abscessed lesions may occur occasionally if there is a secondary bacterial infection present. 

• Head, face and feet are often the areas where the lesions are initially found. Ringworm often occurs in areas that are frequently groomed including muzzle, bridge of the nose, eyelids, pinnae, ear bases, paws (may involve the nail beds), and legs.
  • Young rabbits that are still nursing may pick up the infection around the mouth and muzzle. 
  • Alopecia on the toes and foot pads of rabbits can be caused by a progressive mycotic pododermatitis . Treatment of the disease in its early stages is most effective. Rabbits will often chew their feet and exacerbate the condition. See: Self-mutilation in Rabbits
• Lesions may occur anywhere on the body however it is unusual to see generalised infections unless the animal is suffering from a degree of immunosuppression. 

(B600.9.w9, B601.13.w13, B602.19.w19, B604.5.w5, B606.4.w4, B608.21.w21, B609.2.w2, B610.23.w23, J15.29.w1, J213.4.w4, J213.6.w1)

• In a population of Lepus americanus - Snowshoe hares, scaly lesions with varying alopecia and sometimes inflammation. Histologically, varying degrees of hyperkeratosis, presence of keratotic material in hair follicles, with associated destruction or loss of hair shafts, and cellular poliferation in the stratum spinosum leading to slight thickening of the epidermis focally. In rhe dermis, usually only minimal inflammation wit minimal cellular infiltartion and slight capillary hyperaemia. Numerous septate hyphae and spores were found in the stratum corneum and along the cuticle of the shaft of infected hairs. The fungus was identified as Trichophyton mentagrophytes, (J332.37.w2)

• Typical circular alopecic ringworm lesions, with thickened, itchy and scaly skin. (B626.8.w8)
  • Lesions are similar to those seen in cats. (J213.6.w3)
• In one ferret colony, lesions were described as "large circumscribed areas of alopecia and inflammation on all parts of the body", with thickened, red skin covered in crusts. Lesions regressed with time. (J196.67.w1)

Incubation

• Unclear.
  • In one animal, following a period of contact with an infected individual, infection was first observed six months after the animals had been separated. (J152.11.w1)
  • Two wild individuals were observed to change from non-infected to infected, in one case during a three month period since last being checked, in another during a 15 month period. (J152.11.w1)

Mortality / Morbidity

• Incidence of infection is high. (P17.24.w4)
• Incidence of infection is low in young (less than one year old) animals: 5/66 (7.6%) in one study, compared to 18/59 (30.3%) of older (over one year of age) animals. (J152.7.w2)
• Incidence of infection may be higher in urban than rural hedgehogs, possibly related to higher population density.  (J152.7.w2)
• Incidence is low. (B259.w7)

• Severe ringworm lesions are not uncommon in bears from bile farms. (D263.w7)

• Clinical disease is uncommon in pet rabbits. (B600.9.w9, B609.2.w2)
• Asymptomatic carriers of dermatophytes are common. (B604.5.w5)
  • Studies have detected dermatophytes in 0 to 6.5% of asymptomatic rabbits. (J3.146.w2)
  • In other studies, carrier rates have been up to 36%. (J213.6.w1)
• Ringworm associated with Trichophyton mentagrophytes was seen in 22/63 (35%) Lepus americanus - Snowshoe hare on an island in Flathead Lake, northwestern Montana, October 1953 - July 1954. A severely affected juvenile was found dead in a live trap; if was considered possible that the ringworm infection contributed to its death. The "disappearance rate" of affected hares was higher than the disappearance rate of unaffected hares. (J332.37.w2)

• Uncommon in ferrets. (B626.8.w8, J213.6.w3)
• In one ferret colony, outbreaks occurred in kits in three successive years (in kits of 2/50 litters the first year, five litters the second year and 10 litters in the third year), then was not seen again. Lesions spontaneously regressed, but some affected kits weakened and died at two to three weeks of age. (J196.67.w1)

Pathology

• Skin: 
  • A vigorous tissue response may be seen, with hyperkeratosis and copious inflammatory exudate which may infiltrate the stratum corneum. Polymorphonuclear leucocytes may be present in the vicinity of infected hair follicles. (J152.2.w2)
  • Mycelium may be visible but may be present only in a few hair follicles, invading the intrafollicular stratum corneum and the hair root. (J152.2.w2)

• "Ring worm" lesions of one to eight cm. 
• Lesions are commonly found on the head and abdomen.

(B16.9.w9, B64.26.w5)

Histopathology:

• Hyperkeratotic and acanthotic epidermis with a diffuse polymorphonuclear leucocyte infiltration of the underlying dermis. Lymphocytes and plasma cells may also be seen in the dermis and adnexal structures. (B602.19.w19, B614.15.w15, J213.6.w1)
• There may also be a secondary bacterial abscessation of the hair follicles. (B614.15.w15)
• Mycotic elements can be identified with the appropriate stains. (B614.15.w15)
• In one outbreak in laboratory rabbits, mycelia and spores were present in hair follicles. (J495.32.w7)

Human Health Considerations

Zoonosis

Hedgehogs

• Hedgehogs have been recognised as a source of infection for human ringworm since the late 19th century. (J35.121.w1)
  • This is probably the commonest zoonosis to be caught by carers from hedgehogs. (B284.6.w6, B337.3.w3)
  • Staff must be educated about the clinical signs of ringworm infection in humans and should be instructed to record suspected zoonotic infection in a record book and consult a doctor for medical advice.(V.w26)
• May cause intensely irritating infection in humans. (B156.7.w7, B228.9.w9, B284.6.w6).
  • Initial lesion in humans of thickened epidermis with small fluid-filled vesicles beneath. (J15.21.w1, B284.6.w6)
  • Rapidly spreading eczema-like skin scaling. (B228.9.w9, B284.6.w6)
  • May become secondarily infected by bacterial (e.g. staphylococcal) infection. (B228.9.w9)
• Infection has been reported from contact with a pet hedgehog, resulting in a number of "raised itchy lesions". (J9.188.w1)
• "Rapidly spreading itching lesions" resulted from experimental infection by application to the scarified skin of a human volunteer of Trichophyton isolated from a hedgehog from Dunedin, New Zealand. (J9.188.w1)
• Lesions caused by Trichophyton erinacei may be different from those seen with classical ringworm. (B117.w2, J3.128.w2, P23.1999S.w8)
• Direct contact is required for human infection from hedgehogs. (P23.1999S.w8)
• Wearing rubber gloves when handling hedgehogs may reduce the chance of transmission of this and other zoonotic diseases. (P23.1999S.w8)
• Trichophyton terrestre (which has been cultured from hedgehogs in New Zealand) does not appear to cause ringworm in humans. (J152.2.w1)
• The presence of Trichophyton mentagrophytes var. erinacei in the spines of infected hedgehogs may facilitate transmission to humans. (J152.2.w2)

Rabbits

• Ringworm is a potential zoonosis. (B602.19.w19, B608.21.w21, B609.2.w2, J3.146.w2)
• Note: Asymptomatic rabbit carriers of the dermatophyte are common and can act as a reservoir for other animals and caretakers. (B604.5.w5)
• Trichophyton mentagrophytes may infect the human caretaker before it is noticed on the animal. (B604.5.w5)
• Although ringworm in pet rabbits is uncommon, it is important to be aware of this possibility particularly in rabbits kept as children's pets. (J3.146.w2)
• People that have atopy or who are immunosuppressed are more likely to be at risk. (B610.23.w23)

Ferrets

• Considered a potential zoonosis, although transmission to humans from ferrets has not been reported. (B626.8.w8, B627.17.w17, J213.6.w3)

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

In Hedgehogs:

• Isolations of Trichophyton (identified in one case as Trichophyton mentagrophytes) in 7/26 (27%) of live and dead hedgehogs collected from the Dunedin area, New Zealand. (J9.188.w1)
• Trichophyton mentagrophytes var. erinacei isolated from 51/114 (44.7%) of Erinaceus europaeus - West European Hedgehog in one study in New Zealand. (J152..3.w1)
• Trichophyton mentagrophytes var. erinacei in hedgehogs Erinaceus europaeus in New Zealand. (P17.24.w4)
• Trichophyton erinacei has been isolated from hedgehogs in the UK on a number of occasions and may be present on as much as 50% of the population. (J3.128.w2)
• Trichophyton mentagrophytes var. erinacei isolated from 3/11(27%) hedgehogs Erinaceus europaeus from Yorkshire. (J152.2.w2)
• Seen occasionally in hedgehogs presented to a UK wildlife hospital. (B259.w7)
• Trichophyton mentagrophytes infection has been seen twice in conjunction with Caparinia tripilis infection.(B291.12.w12)

In Elephants:

• Reported rarely in elephants. (B64.27.w4)

Elephas maximus - Asian Elephant

• Ringworm has been reported in Elephas maximus - Asian Elephant from East Asia. (P501.1.w2)

In Bears:

• Ringworm infection has been reported in bears (species not specified). (B10.48.w43)
• Microsporum canis associated with skin lesions in two Helarctos malayanus - Sun bears. (J4.155.w5)
• Trychophyton spp. in Ursus americanus - American black bear cubs undergoing rearing and rehabilitation. (B338.23.w23, J417.20.w1)

In Lagomorphs:

• Ringworm is uncommon in domestic rabbits (Oryctolagus cuniculus domesticus). (B600.9.w9, B614.15.w15, J3.146.w2)
  • Domestic rabbits are susceptible to infection; however, clinical disease is less common than asymptomatic infection. (B600.9.w9, B609.2.w2, J3.146.w2)
    • Asymptomatic carriers of dermatophytes are common. (B604.5.w5)
    • Studies have detected dermatophytes in 0 to 6.5% of asymptomatic rabbits. (J3.146.w2)
    • In other studies, carrier rates have been up to 36%. (J213.6.w1)
    • Trichophyton mentagrophytes
      • In one study, four of 104 healthy rabbits (3.8%) were found to be infected with Trychophyton mentagrophytes var. mentagrophytes, as well as one rabbit with skin lesions. All rabbits except one, were under six months old. (B610.23.w23, J3.146.w2, J213.6.w1)
      • This species of fungus can be isolated from the skin and haircoat of approximately 36% of normal, healthy rabbits. (B608.21.w21)
• Ringworm is infrequent and generally sporadic in wild lagomorphs. (B614.15.w15)
• Ringworm associated with Trichophyton mentagrophytes was seen in 22/63 (35%) Lepus americanus - Snowshoe hare on an island in Flathead Lake, northwestern Montana, October 1953 - July 1954. (J332.37.w2)
• Microsporum cookei cultured from 0.5% of 207 Sylvilagus floridanus - Eastern cottontail from south-west Georgia, USA. (J13.19.w2)

In Ferrets

• Ringworm has been reported in ferrets. (J196.67.w1)
• Mycosporum canis has been isolated from ferrets in New Zealand; all eight isolates over a period of 20 years were this fungus. (J195.24.w2)

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

• Elephants (Elephantidae - Elephants (Family))
  • Elephas maximus - Asian Elephant
  • Erinaceus europaeus - West European Hedgehog
• Bears (Ursidae - Bears (Family))
  • Helarctos malayanus - Sun bear
• Lagomorphs (Lagomorpha - Lagomorphs (Order))
  • Lepus americanus - Snowshoe hare
  • Oryctolagus cuniculus domesticus - Domestic European rabbit
• Mustelids (Mustelidae - Weasels (Family))
  • Mustela putorius furo - Ferret

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

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

• Isolations of Trichophyton (identified in one case as Trichophyton mentagrophytes) in 7/26 (27%) of live and dead hedgehogs collected from the Dunedin area, New Zealand. (J9.188.w1)
• Trichophyton mentagrophytes var. erinacei in hedgehogs Erinaceus europaeus in New Zealand. (P17.24.w4)
• Trichophyton erinacei has been isolated from hedgehogs in the UK on a number of occasions and may be present on as much as 50% of the population. (J3.128.w2)
• Ringworm has been reported affecting wild hedgehogs in Bushy Park, UK. (J152.11.w1)
• Seen occasionally in hedgehogs presented to a UK wildlife hospital. (B259.w7)

In Lagomorphs:

• Ringworm is infrequent and usually sporadic in wild lagomorphs. (B614.15.w15)
• Ringworm associated with Trichophyton mentagrophytes was seen in 22/63 (35%) Lepus americanus - Snowshoe hare on an island in Flathead Lake, northwestern Montana, October 1953 - July 1954. (J332.37.w2)
• Microsporum cookei cultured from 0.5% of 207 Sylvilagus floridanus - Eastern cottontail from south-west Georgia, USA. (J13.19.w2)

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
• Lagomorphs (Lagomorpha - Lagomorphs (Order))
  • Lepus americanus - Snowshoe hare

(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 hedgehogs: UK, New Zealand. (P23.1999S.w8, J3.128.w2, J9.188.w1, P17.24.w4)
• In lagomorphs: 
  • UK (B600.9.w9)
  • USA (B609.2.w2)

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

• In hedgehogs: UK, New Zealand. (P23.1999S.w8, J3.128.w2, J9.188.w1, P17.24.w4)

General Information on Investigation / Diagnosis

• In dogs and cats a Woods lamp (ultraviolet light) may be used for preliminary screening: hairs infected with Microsporum canis, Microsporum distortum or Microsporum audouini fluoresce apple-green. (B47)
• Direct microscopic examination of skin scrapings and hair. Clear using 20% potassium hydroxide (KOH) (place in a drop of KOH and warm gently) or stain with Periodic acid-Schiff stain (PAS): fungal elements stain deep red. Hyphae and conidia may be visible. The size and arrangement of conidia assist in identification of the fungal species involved. (B47)
• Culture of skin scrapings and hair on Sabouraud's dextrose agar and on Dermatophyte Test Medium in a moist atmosphere for 1-4 weeks. Examine colonies (growth rate, texture, colour, reverse pigmentation), microscopic examination (conidia, hyphae types). Trichophyton test media may be used to differentiate Trichophyton species. (B47)

• Clinical appearance may be suggestive but is not pathognomonic. (B284.6.w6)
• Scales may be observed following preparation in potassium hydroxide (KOH) for the presence of mycelium. (J152.2.w2); this is not reliable. (B284.6.w6)
• Hairs or spines may be stained (PAS) and examined for the presence of mycelium and/or arthrospores (both mycelium and arthrospores may be found on the surface of spines and within spines. (J152.2.w2); this is not reliable. (B284.6.w6)
• Presence of fungi may be demonstrated on skin biopsy. (B284.6.w6)
• Culture on e.g. Sabouraud's agar at 28°C (B228.9.w9, B284.6.w6); Dermatophyte Test Medium (Fungassay, C-Vet) (J15.21.w1) is required for confirmation as Trichophyton does not fluoresce. (B156.7.w7, J15.21.w1, B284.6.w6, B337.3.w3)
  • Trichophyton erinacei white, finely textured colonies with bright yellow or greenish staining of the agar and no urease enzyme (B228.9.w9); yellow to orange rather than red pigment. (J152.2.w2)
  • Trichophyton mentagrophytes is positive for urease. (B228.9.w9)

• Tentative diagnosis based on the presence of typical ringworm lesions; definitive diagnosis by culture from hairs from the affected areas. (B16.9.w9, B338.23.w23, J4.155.w5)
• Examination of skin scrapings. (B407.w18)
• Skin scrapings of the lesion, cleared in potassium hydroxide and examined microscopically to detect Microsporum spp. mycelium and/or spores. (B16.9.w9, B64.26.w5)

Fungal culture

• This is the best method of confirming diagnosis. (B64.22.w8, B602.19.w19, B609.2.w2, B610.23.w23, J213.4.w4)
• Method
  • For clinical disease: 
    • Pluck hairs from the edge of an alopecic lesion. (B609.2.w2, J495.32.w7)
    • Skin scrapings/samples may also be cultured. (B602.19.w19, B604.5.w5, J495.32.w7)
  • For detection of asymptomatic infections:
    • The entire body is brushed with a sterile toothbrush or surgical scrub brush and the brushings (hair and cellular debris) are then cultured (Mackenzie's toothbrush technique). (B600.9.w9, B604.5.w5, J3.146.w2)
  • Incubate the samples at 25ēC on a dermasel agar. (B600.6.w6)
  • Cultivate aerobically at room temperature for a minimum of ten days. (B604.5.w5)
  • Sabouraud's medium can be used for culture of ringworm. (B606.4.w4, J495.32.w7)
  • DermatophyteTest Medium:
    • This medium has a colour indicator: when the medium becomes alkaline it changes from the original yellow colour to red. (B609.2.w2, J213.6.w1)
    • Dermatophytes typically produce this red change in the media during the early growth phase of their culture (B609.2.w2); "as soon as the dermatophyte mycelium growth is noticed". (J213.6.w1)
    • Saprophytic fungi growth will also produce the red change in the media but only in the late growth phase (after the mycelium has developed and been present for several days), therefore it is important to examine the media daily. (B609.2.w2, J213.6.w1)
• Positive culture: 
  • This indicates the existence of a dermatophyte. (B609.2.w2)
    • False positives can occur if the culture was positive for just a transient dermatophyte, e.g. if a culture was obtained from the feet which had come in to contact with a geophilic dermatophyte. (B609.2.w2)
• Negative culture:
  • If a plate does not show growth of fungi within three weeks, it can be considered negative. (B600.6.w6)
    • False negatives do occur. (B609.2.w2)
• Identification of the species of fungi should be performed by macroscopic and microscopic examinations (for details on identification see the section at the top of this page on Infectious / Non-infectious Agent(s)). Saprophytic fungal growth can be identified macroscopically as a black, dark brown or grey culture. Microscopic examination should not be performed before five to seven days from the first observation of fungal growth. For microscopic examination, place a piece of tape against the fungal colony and then examine on a microscope slide with one drop of cotton blue lactophenol. (J213.6.w1)
  • Colony morphology and characteristics of macroconidia can be used to indicate fungal species. (J495.32.w7)

Wood's Lamp Examination

• This may be diagnostic for some forms of Microsporum canis (50% of strains). (B604.5.w5, J213.6.w1)
• Many pathogenic dermatophytes (including the most common dermatophyte in rabbits: Trichophyton mentagrophytes) do not fluoresce so this is not a particularly useful screening tool. (B600.9.w9, B602.19.w19, B609.2.w2)
• False-positive fluorescence is quite common and will appear white or blue in colour. (B609.2.w2, J213.6.w1)
  • This may occur due to debris, scales, bacteria or keratin associated with epidermal sebum on skin and hair. (B609.2.w2, J213.6.w1)
• The lamp needs to be warmed up for a minimum of five minutes and then it also needs to be exposed to the suspicious lesion for several minutes. (B609.2.w2, J213.6.w1)
• A true positive reaction that is associated with Microsporum canis is an apple-green fluorescence at the base of the hair shafts. (B609.2.w2, J213.6.w1)

Microscopic examination of hair shaft or skin scrapings

• Hair shafts: 
  • "The presence of fungal spores in broken hair shafts plucked from a lesion is diagnostic of dermatophytosis". (B600.6.w6)
• Skin scrapings: 
  • Collect the samples from the periphery of the lesion and then mount samples in 10% potassium hydroxide under a cover slip. (B64.22.w8, B600.6.w6, B602.19.w19, J213.4.w4)
  • It may be possible to see fungal mycelia and ectothrix arthrospores. (B600.6.w6, B602.19.w19)

Skin biopsy

• Useful in confirming true fungal invasion and infection. (B609.2.w2, B614.15.w15)
• One of the following stains can be used to identify fungal elements:
  • Periodic acid-Schiff stain (B602.19.w19, J213.6.w1)
  • Gomori's methenamine silver (B602.19.w19, J213.6.w1)
  • Gridley fungal stain (B602.19.w19)
• It may be possible to see fungal mycelia and arthrospores. (B602.19.w19)
• Useful in ruling out other causes of alopecia. (B609.2.w2)

Indirect ELISA

• An indirect ELISA has been developed for Trichophyton mentagrophytes. (B601.13.w13, B610.23.w23)

• Inspection under a Wood's lamp, and microscopic examination of hairs can be used. (B626.8.w8)
• May or may not be Wood's lamp positive with Microsporum canis infection. (J213.6.w3)
• Culture on dermatophyte culture medium. (J213.6.w3)

• Environmental Assessment
• History & Documentation
• Physical Examination of Mammals
• Necropsy of Mammals
• Clinical Pathology of Lagomorphs
• Clinical Pathology of Ferrets
• 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)

• Audycoptic Mange in Bears
• Chiggers (Trombiculiasis) (In Waterfowl, Hedgehogs and Bears)
• Demodicosis (with special reference to Hedgehogs and Bears)
• Dermatophilosis in Bears
• Sarcoptic Mange
  • Note: concurrent ringworm and Sarcoptic Mange sometimes occurs in Ursus americanus - American black bear cubs during rehabilitation. (V.w93)

• Fur mites: 
  • Cheyletiellosis or the less commonly reported Leporacarus gibbus Fur Mite Infection in Lagomorphs.
  • Mite infection may be concurrent with a ringworm infection.
  • 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.
• Psoroptes cuniculi Ear Mite Infection in Lagomorphs:
  • 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 under low magnification.
• Flea Infection
  • Distribution: Often appears in other areas of the body in addition to the head and feet.
  • Clinical signs: patchy alopecia and pruritus. Sometimes see a secondary pyoderma.
  • Diagnosis: fleas or flea dirt found in coat.
• Sarcoptic Mange or Notoedres Mange
  • Both are rare in the rabbit
  • Distribution: head and neck
  • Clinical signs: very pruritic lesions.
• Barbering and Excessive Grooming or Self mutilation in Rabbits
  • Self inflicted or by cage mates.
  • Hair loss without any scale, pruritus or skin lesions.
• Contact Dermatitis
  • Acute onset 
  • Distribution: usually ventral lesions.
• Demodicosis:
  • Very rare.
  • May occur in association with use of corticosteroids.
  • Diagnosis: mites on skin scrape.

• Lack of grooming:

  • Caused by obesity or an underlying musculoskeletal or dental disease.
  • Clinical signs: scale accumulation especially in the intrascapular region.

• Injection Reactions

  • 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
  • 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)

• Alopecia areata:
  • Genetic hair loss (B10.45.w47)
• Moist Dermatitis in Lagomorphs (J213.6.w1)
• Trauma (J213.6.w1)
• Treponematosis in Lagomorphs
  • Proliferative, scaly lesions of treponematosis on the lips and nose are commonly mistaken for ringworm lesions. (B602.18.w18)

• Sarcoptic Mange (with special reference to Hedgehogs, Bears, Lagomorphs and Ferrets)

Specific Medical Treatment

• Topical natamycin (Mycophyte, Intervet), or enilconazole (Imaverol, Janssen Animal Health). Oral griseofulvin (J15.21.w1)
• Enilconazole (Imaverol - Janssen Animal Health) diluted 1 part per 50 parts lukewarm water. Place within a shallow container ensuring that the depth of fluid is not too great for the hedgehog. Bathe the conscious hedgehog with the solution paying attention to covering all areas of its body whilst avoiding the animal inhaling the solution. Bath four times at three day intervals and reassess case progress after this course of treatment (V.w26)
  • Clipping spines and removing excess scale and scurf may be useful to increase penetration of the topical medication to the skin over affected areas. (V.w26)
  • Ensure that the hedgehog is placed in a disposable box with absorbent material clearly marked for use “for ringworm hedgehogs only” and is kept in a warm area to avoid chilling following treatment. (V.w26)
• Enilconazole (Imaverol, Janssen Animal Health, mix 1:50 with sterile water, apply as a spray, once daily) (B151); continue treatment for at least 50 days (J60.1.w1)
• Bathe in enilconazole (Imaverol, Janssen Animal Health) twice weekly plus griseofulvin on food (D66)
• Oral griseofulvin sprinkled on the food. (B259.w7)
• Oral griseofulvin alone or in combination with topical therapy: griseofulvin 1/4 of a tablet (125 mg/tablet) for animals under 500g bodyweight, 1/2 tablet for animals over 500 g bodyweight, daily for at least four weeks, plus topical treatment with enilconazole (Imaverol, Janssen Animal Health), 100 mg/ml diluted 1:50 with water, three baths at two day intervals. Localised topical treatment with antifungal creams such as clotrimazole (Canesten, Bayer) may also be used. (B291.12.w12)
• Vitamin A supplementation may be of value as an additional therapy. (B291.12.w12)

Note: Recovery, with regeneration of skin and spines, takes a long time. (B284.6.w6)

• Microsporum canis has been treated with 500 mg/day oral griseofulvin in the diet for 30 to 60 days. (B16.9.w9, B64.26.w5)
• Griseofulvin (microcrystalline), orally, at 500 mg per day for each of two Helarctos malayanus - Sun bears, approximate bodyweight 45 kg each; 250 mg/day appeared to be ineffective. (J4.155.w5)
• For Ursus americanus - American black bear cubs, griseofulvin (Fulvicin, Schering) microsize, 10 mg/kg orally twice daily for 4-6 weeks, or for at least 21 days and continuing for one to two weeks after clinical signs have ceased. Additionally, topical treatment (on affected areas or the whole bear) with lyme sulphur solution. (B338.23.w23)
  • Note: griseofulvin can cause low leucocyte count. Check the blood count every two to three weeks during treatment, or if the bear shows any adverse clinical signs. (B338.23.w23)

Notes:

• Antifungal treatments that are safe for use in kittens can be used for medicating rabbits. (B336.42.w42)
• Treatment regimes are similar regardless of the fungal species isolated. (J213.6.w1)
• Imidazole-containing lotions and creams may not be effective as they don't penetrate infected hair follicles and hair shafts. (B602.19.w19)
• Corticosteroids are contra-indicated because systemic or topical use may severely exacerbate dermatophytosis. (B609.2.w2)

Treatment plan:

• Treat all in contact animals. (B609.2.w2)
• Wear gloves to decrease zoonotic risk. (J213.6.w1)
• Clip the fur:
  • Ideally, clip the fur before applying topical medication. (B602.19.w19)
  • However, for local lesions, one author advises against clipping because it can increase the risk of the infection becoming generalised due to iatrogenic skin abrasions and it can also increase environmental contamination. If the animal is a long haired breed then it is usually necessary to clip the fur but only clip the fur that is surrounding the lesion and then this should be disposed of it properly. (J213.6.w1)
• For small, superficial lesions:
  • There are a variety of topical antifungal agents that can be used daily until resolution, e.g. clotrimazole or miconazole creams. In addition to this, a lime sulphur bath or dip is recommended once weekly for four weeks. (J213.6.w1) However washing or dipping small mammals can be difficult and may be stressful for them. (J15.29.w1)
• Widespread lesions or lesions unresponsive to topical treatment:
  • Systemic therapy should be initiated. Griseofulvin is recommended. (J213.6.w1)
• Length of treatment:
  • This varies with different protocols but in general, treatment should continue for a minimum of two weeks past clinical resolution or until there has been two negative fungal cultures with a four week interval in between them. (B602.19.w19, J213.6.w1)
  • Most treatment regimes last for a minimum of three to four months. (B602.19.w19)
• Environmental control: this is an important part of the treatment. (J213.6.w1)

Topical therapy options:

• 1% clotrimazole cream or lotion (B600.9.w9, B606.4.w4, J213.4.w4, J213.6.w1)
  • For use in small lesions. (B602.19.w19)
  • Apply to lesions every 12 hours. (B609.2.w2)
  • Avoid use concurrently with cisapride due to the risk of adverse drug interactions. (B600.9.w9)
• Miconazole cream or lotion (B600.9.w9, J15.29.w1, J213.6.w1)
  • For use in small lesions. (B602.19.w19)
  • Apply to lesions every 24 hours for 14 to 28 days. (B609.2.w2)
  • Avoid using concurrently with cisapride due to the risk of adverse drug interactions. (B600.9.w9)
• Lime sulfur dip (J213.4.w4)
  • For use in multiple lesions. Clip the entire coat and dip the rabbit in the solution and then administer Griseofulvin. (B602.19.w19)
  • Use once every seven days. This treatment has been used successfully for ringworm in rabbits. (B609.2.w2, J213.6.w1)
  • It is odiferous and may stain. (B609.2.w2)
  • Dipping is often difficult with rabbits because there is a high risk of skeletal fractures or excessive chilling if performed by inexperienced people. (B609.2.w2)
• Enilconazole 0.2% (B610.23.w23, J15.29.w1)
  • use at a 1:10 dilution (B606.4.w4)
• Other topical treatments- Use twice daily applications of one of the following:
  • Chlorhexidine and water mix 1:10 (B602.19.w19, J15.29.w1)
  • Povidone-iodine (Iodophors) (B602.19.w19, B606.4.w4)
    • dipping the affected toes in a solution of iodine several times a day for weeks may destroy infective fungus in nail beds. (B604.5.w5)
  • 1% Triclosan (B606.4.w4)
  • 2% Chlorhexidine and 2% miconazole shampoo (B602.19.w19, J15.29.w1)
  • Germicidal Barrier Ointment (Health and Hygiene, Sunninghill, South Africa) (J15.29.w1)

Oral medication options:

• Griseofulvin (B600.9.w9, B615.6.w6)
  • 25 mg/kg orally every 24 hours for:
    • four to six weeks. (B609.2.w2, J15.29.w1)
    • thirty days. (J213.4.w4, J213.6.w1)
  • Use in cases with multiple lesions, along with the lime sulfur dip. (B602.19.w19)
  • "If using an ultramicrosized form of griseofulvin, decrease the dose by 50% and give with a high fat meal". (J213.6.w1)
  • Initiate therapy with this drug. Use at a dose of 25-50 mg/kg once daily. (B610.23.w23)
  • "Griseofulvin given orally at a dose of 25 mg/kg twice daily for 4-6 weeks is effective". (B606.4.w4)
  • Less effective than Itraconazole. (B609.2.w2)
  • Use in refractory cases or animals that are severely affected. (B609.2.w2)
  • Can be difficult to titrate a dose. Tablets can be crushed and suspended in water but it should not be dispensed in this form to owners because adverse effects have been reported on ova and sperm. (J15.29.w1)
  • Tablets can be broken and then given in a small amount of strawberry jam. (B606.4.w4)
  • Precautions:
    • Wear gloves. (B602.19.w19)
    • Bone marrow suppression (pancytopenia, anaemia and neutropenia) has been reported in cats and dogs with prolonged therapy or as an idiosyncratic reaction. This has not been reported in rabbits yet but it might occur therefore it is recommended to do a weekly or biweekly CBC. (B602.19.w19, B609.2.w2)
    • Neurological side effects have been reported in cats and dogs so it is necessary to monitor for this possibility in the rabbit. (B609.2.w2)
    • Gastrointestinal side effects: in cats and dogs, this drug can cause gastrointestinal signs, e.g. anorexia. (J213.6.w1)
  • Contraindications:
    • Griseofulvin is a teratogenic so it should not be used in the first two trimesters of pregnancy. (B609.2.w2)
• Ketoconazole
  • Use in rabbits that will not tolerate griseofulvin. (B602.19.w19, J213.6.w1)
  • 10 to 15 mg/kg orally every 24 hours. (B602.19.w19, B609.2.w2)
  • 10 to 40 mg/kg/day orally (J213.6.w1) for fourteen consecutive days has been reported by one author in 1983, as being highly effective. (B604.5.w5)
  • Safety and efficacy in rabbits is unknown. (B609.2.w2)
  • Hepatopathy reported in cats and dogs may be quite severe. (B609.2.w2)
  • Contraindications: 
    • Do not use in breeding animals as this drug may affect steroidal hormone synthesis, particularly testosterone. (B602.19.w19, B609.2.w2)
• Itraconazole
  • 5 mg/kg orally every 24 hours for three to four weeks. (B609.2.w2)
  • 5-10 mg/kg orally every 24 hours. (B602.19.w19)
  • Use in refractory cases or animals that are severely affected. (B609.2.w2)
  • 10 mg/kg once daily seems to be safe and effective in rabbits. (J15.29.w1)
  • Itraconazole may be a safer option to dispense to owners than griseofulvin, especially as Itraconazole is supplied in liquid form. (J15.29.w1)
• Terbinafine
  • 8-20 mg/kg orally every 24 hours. (B602.19.w19)
• Lufenuron
  • This medication has been successful in treating fungal infection in cats and dogs. (J213.6.w1)
  • Lufenuron is used to treat fleas by acting as an insect growth regulator by inhibiting chitin synthesis, polymerisation and deposition. Fungal cell walls also contain chitin and other complex polysaccharides so are affected by this medication. (J213.6.w1)
  • There are anecdotal reports of usage in rabbits at 135 mg/kg orally every four weeks until resolution. Lufenuron should be given with a meal that is high in fat. (J213.6.w1)

Eliminating dermatophytes from large rabbit colonies

• Carriers of Trichophyton mentagrophytes were reduced after using one of either:
  • 1% Copper Sulphate- used successfully for dipping rabbits. (B602.19.w19, J213.6.w1)
    • dip twice weekly for three to four weeks. (B614.15.w15)
    • Dipping is often difficult with rabbits because there is a high risk of skeletal fractures or excessive chilling if performed by inexperienced people. (B609.2.w2)
  • Metastabilized chlorous acid / chlorine dioxide (MECA)
    • "a topically applied two-component commercial cold disinfectant". (B615.6.w6)
    • (LD disinfectant, Alcide Corp., Norwalk, CT)
    • This can be used diluted one part base compound, to one part activator compound, to ten parts tap water, and is then massaged into the fur. (B602.19.w19, B615.6.w6, J213.6.w1)
    • This has been used to spray large numbers of infected rabbits and also to treat the environment. (B602.19.w19)
      • Use twice weekly for three to four weeks using around eight ounces per rabbit at each application. (B614.15.w15)
    • The LD disinfectant is more commonly used as an environmental disinfectant and is apparently nontoxic, nonirritating, and non-mutagenic. (B604.5.w5)
    • "The authors conclude that LD disinfectant and copper sulfate may serve as economically feasible alternatives to conventional dermatophyte treatments when large numbers of animals are involved". (B604.5.w5)
  • Treatments were used six times over a twenty six day period. (J213.6.w1)
    
• Griseofulvin-medicated diets or drinking water
  • Used in large dermatophye outbreaks. (B10.45.w47, B602.19.w19)
  • The cost may be prohibitive. (J213.6.w1)
  • 0.825 g per kilogram of diet. (B602.19.w19)
  • 0.75 g per kg of feed for fourteen days. (J213.6.w1)
  • Or 20 mg/kg in the feed (300 grams per 3 tons of feed) for 25 days or longer. (B604.5.w5)
  • 0.375 grams of powdered griseofulvin per pound of feed for fourteen days. (B614.15.w15)

• Griseofulvin, 25 mg/kg orally. (B626.8.w8)
  • N.B. Adverse effcts have been reported with griseofulvin. (J213.6.w3)
• Shave the affected area and treat this area with keratolytic shampoo and miconazole cream. (J213.6.w3)
• If systemic treatment is considered appropriate, itraconazole (oral suspension) should be used. (J213.6.w3)
• Continue treating until a month after clinical signs have resolved. (J213.6.w3)
• Note: this disease can be self-limiting. (B626.8.w8, J213.6.w3)

• Treatment and Care - General

General Nursing and Surgical Techniques

Other important considerations in treating a ringworm epizootic:

• Reduce stress
• Eliminate other pathogens
• Improve the environmental conditions

(B614.15.w15)

• Treatment and Care - General

Preventative Measures

--

• There is a modified live Trichophyton mentagrophytes vaccine that may be a useful prophylaxis. (B608.21.w21)
• Remove ectoparasites. (B604.5.w5)

• Preventative Medicine for Mammals
• Treatment and Care - General

Environmental and Population Control Measures

HEDGEHOGS

• Dispose of or disinfect accommodation following treatment. (V.w26)

• Avoid infective soil if there is a geophilic dermatophyte involved. (B609.2.w2)
• It is important to treat the environment especially in recurrent cases. (B609.2.w2)
• Dispose of any bedding, brushes or rugs. (J213.6.w1)
• Vacuum all the contaminated areas. (B602.19.w19)
• Regularly clean or vacuum the cage during the treatment period and properly dispose of the vacuum bag after each use. (J15.29.w1, J213.6.w1)
• Metal/plastic parts of the cage should be soaked in a sporicidal disinfectant. All traces of the disinfectant need to be rinsed away to prevent any potentially toxic exposure to the animal. (J15.29.w1)
  • Diluted household bleach (1:10) (Hypochlorites) - practical and relatively effective (not 100% effective in killing fungal spores). Use to clean all surfaces. (B602.19.w19, B604.5.w5, B609.2.w2, J15.29.w1, J213.6.w1)
  • Concentrated bleach (Hypochlorites) and Formalin (1%) - effective means of killing spores but their use is not particularly practical in many situations. (B609.2.w2)
  • Chlorhexidine - ineffective in pilot studies. (B609.2.w2)
  • Metastabilized chlorous acid / chlorine dioxide 
    • diluted with activator compound and water 1:1:10 respectively. (B602.19.w19)
  • Enilconazole spray or fogger
    • A solution of this drug can be made into a spray and then used at a rate of 50 mg/metre˛ twice a week for five months. (B606.4.w4)
    • May be useful in rabbitries or households (J213.6.w1)
    • Foggers that contain formaldehyde or enilconazole are preferable to steam cleaning for carpets as steam cleaning will not reach a high enough temperature to kill infectious spores. (B602.19.w19, J213.6.w1)
  • Benzalkonium chloride - effective in the environmental control of ringworm. (B604.5.w5)
  • Glutaraldehyde - effective in the environmental control of ringworm. (B604.5.w5)
• Eliminate any wild rats or mice from the environment as they are often carriers of this disease. (B606.4.w4)
• As a general preventative measure:
  • maintain high standards of husbandry particularly with aged, young, stressed or pregnant rabbits. (B604.5.w5)
  • maintain optimal adjustment of humidity and temperature. (B604.5.w5)

• Following three years of outbreaks in a ferret colony, "the wooden nestboxes were dipped in a lye solution and allowed to dry." No further cases occurred. (J196.67.w1)

• In the colony situation it may be best to eliminate carriers. (B604.5.w5)
• Isolate affected animals from nonaffected animals. (J213.6.w1)

• Ensure all hedgehogs with suspect or confirmed ringworm infection are kept in isolation within disposable or easily disinfected accommodation. (V.w26)
• Handle affected individuals wearing gloves, and last, to reduce the chance of spreading infection to other individuals. (B337.3.w3)

• Initiate a quarantine period and all animals that are entering the household must be subjected to dermatophyte cultures. (B609.2.w2)

• Environmental and Population Management - General