Scaly Leg Mites
BASICS
Definition: Cnemidocoptes pilae / Knemidokoptes pilae17,29 affects psittaciforms,3 Knemidocoptes jamaicenis affects passerines3
Other Names: Leg and Foot Mange,29 Knemidocoptic mange,27 Scaly Face Mite, Cere Mite (budgies)3
Disease Process: These are the most common mites parasitizing pet birds.3 They burrow into unfeathered areas (invading feather follicles and the stratum corneum) to feed on keratin,3 resulting in proliferation of the tissues most commonly of the feet and legs in passerines.5 The beak, cloaca, and skin around the eyes can also be affected,2,5,17,29 although this is more commonly seen in parrots. Proliferative tissue may have a tiny "honey comb" appearance. The mites can also result in feather loss as well as itchiness of the head and neck.16 If severe, excessively large scales can cause constriction (impaired circulation and possibly necrosis) of the legs/toes and may predispose to Staphylococcus infections of the skin and joints.28,29 These mites complete their entire life cycle on the bird, so close or direct contact between birds is required for transmission16,29 (e.g. transfer from parent to chick).3
Risk Factors: Young and inbred birds5 seem most affected; an underlying immunodeficiency3,5,29 and a genetic predisposition have been suggested as possible risk factors.
Contagious?: Although these mites are contagious among birds, those birds with robust immune systems may not show clinical disease, so that multiple birds sharing the same cage may not all appear affected to the same degree.3,5
Other Names: Leg and Foot Mange,29 Knemidocoptic mange,27 Scaly Face Mite, Cere Mite (budgies)3
Disease Process: These are the most common mites parasitizing pet birds.3 They burrow into unfeathered areas (invading feather follicles and the stratum corneum) to feed on keratin,3 resulting in proliferation of the tissues most commonly of the feet and legs in passerines.5 The beak, cloaca, and skin around the eyes can also be affected,2,5,17,29 although this is more commonly seen in parrots. Proliferative tissue may have a tiny "honey comb" appearance. The mites can also result in feather loss as well as itchiness of the head and neck.16 If severe, excessively large scales can cause constriction (impaired circulation and possibly necrosis) of the legs/toes and may predispose to Staphylococcus infections of the skin and joints.28,29 These mites complete their entire life cycle on the bird, so close or direct contact between birds is required for transmission16,29 (e.g. transfer from parent to chick).3
Risk Factors: Young and inbred birds5 seem most affected; an underlying immunodeficiency3,5,29 and a genetic predisposition have been suggested as possible risk factors.
Contagious?: Although these mites are contagious among birds, those birds with robust immune systems may not show clinical disease, so that multiple birds sharing the same cage may not all appear affected to the same degree.3,5
CLINICAL DISEASE
Signalment: Most commonly seen in canaries and budgies, but may also affect other passerines (especially European Goldfinches) and psittacines5,17
Symptoms:
Symptoms:
- hyperkeratosis (scaly or crusty proliferations) of the feet* (predominantly)5 and base of the beak3,28
*proliferative yellow-colored crusts often start on plantar surface of foot then enlarge5 - "tassel foot" in canaries and goldfinches2,5,27,29
- difficulty perching / shifting leg lameness5
- itchiness (rarely noted)28
DIAGNOSIS
Differentials: Hyperkeratosis, dermatomycoses, papillomavirus, fiber constriction, cutaneous poxvirus;28 consider old age and poor nutrition in mild cases5,28
Testing: Mites and/or eggs can be seen microscopically in scrapings (mixed with oil) of the lesions,2,3,5,17 or inferred by witnessing the small bore holes within the hyperkeratotic lesions.27,28
Testing: Mites and/or eggs can be seen microscopically in scrapings (mixed with oil) of the lesions,2,3,5,17 or inferred by witnessing the small bore holes within the hyperkeratotic lesions.27,28
TREATMENT
Immediate:
Long-term: Treat any underlying condition that predisposed a bird to having an inadequate immune response--reduce stress, improve nutrition, etc.3
- Treat locally using plant oil (caution: use sparingly to avoid getting oil on feathers)3,27,28 to suffocate mites in conjunction with ivermectin 'spot on' (200ug/kg)3,27,28 (diluted in propylene glycol or sterile water 1:8); ivermectin can also be given orally.5,27,29 Ivermectin precipitates out of solution so mix well before administration.
- Treat all birds sharing the cage simultaneously16 (even if some aren't showing symptoms).
- Repeat ivermectin dose 3 weeks later.5
-OR- Administer 2-3 repeat treatments 10-14 days apart for eradication.16
-OR- Repeat dose every 7-10 days for 2-3 total applications.27
-OR- Administer 1 treatment per week for 3 weeks, then 1 treatment 1 month later.3 - If severe, excessively large scales can cause constriction of the legs/toes and may predispose to Staphylococcus infections. Severe cases may therefore require surgical debridement of the enlarged scales.28
- Antibiotic emollient creams will soften and hydrate the skin while treating bacterial infection.28
- Remove leg band(s) if causing constriction.
Long-term: Treat any underlying condition that predisposed a bird to having an inadequate immune response--reduce stress, improve nutrition, etc.3
TYPICAL OUTCOME
Ivermectin treatment is typically effective, however, lesions may persist for weeks or months and recede as new skin growth occurs; corrective beak trims may be required (trimming may need to be a life-long requirement if the beak's germinal cells were affected).3 This disease process is slower to respond to treatment in canaries and finches than it is in budgies.29
PREVENTION
CONSIDERATIONS
Budgies have this mite on their bodies a majority of the time, but usually remain asymptomatic until certain conditions that lower the bird's immune system (stress, malnutrition, disease, etc.) allow the mites to multiply.3
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