Knemidocoptiasis in birds - Veterinary Medicine
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Knemidocoptiasis in birds
Knemidocoptes species mites burrow into unfeathered skin in birds, causing unsightly, uncomfortable, and potentially life-threatening lesions. Here's how to identify and eradicate an infestation with these opportunistic mites.


VETERINARY MEDICINE


TREATMENT AND PREVENTION

Isolate and treat all birds with lesions and any birds that have had direct contact with symptomatic birds.

Ivermectin


Table 2 Diluting Ivermectin for Topical or Oral Use in Birds
Ivermectin is the drug of choice and may be given orally, topically, or by injection.25-27 Topical or oral dosing is recommended for small birds. Ivermectin may be toxic if given intramuscularly, especially in small birds, and death may occur.28 Two large-animal injectable propylene-glycol–based formulations of ivermectin (Ivomec—Merial) are available for extralabel use in birds in 1% (10 mg/ml) and 0.27% (2.7 mg/ml) concentrations.

For small and tiny birds, ivermectin can be diluted for safer oral or topical dosing. Many anecdotal dilutions are used; a 1:4 dilution is often recommended. See Table 2 for two easy-to-prepare ivermectin dilution formulas for oral or topical administration. Dilute the bovine preparation (which contains propylene glycol) with propylene glycol because the ivermectin will precipitate if mixed with water. Thoroughly mix the solution before administration because ivermectin settles out in propylene glycol. When given orally, propylene glycol has been associated with tracheal necrosis in some birds, and certain species are sensitive to propylene glycol, such as keel-billed toucans (Ramphastos sulfuratus).29

The suggested ivermectin dosing regimen is 200 to 400 μg/kg given orally or topically for two to three treatments at 10-day intervals.25-27 For most species, give 200 μg/kg, and repeat in 10 to 14 days. Canaries usually require a longer treatment period than budgerigars do; three to six treatments are often needed before resolution is achieved. Because topical ivermectin administration at 0.4 mg/kg was found to be toxic in finches, use the 0.2 mg/kg dose for passerines and other sensitive individuals.28

If diluted ivermectin is not available, moisten the feathers on the neck with water or an alcohol-soaked cotton ball, and apply one drop (0.01 ml) from an insulin syringe to the skin over the jugular furrow. Alternatively, apply a light coating of 0.1% ivermectin topically on the affected areas of skin (e.g. cere, feet) for three consecutive days, and repeat in one week.

Although autoclaving diluted ivermectin to obtain a sterile form for injection has been discussed by some practitioners, it is not recommended. The melting point of ivermectin (311 F [155 C]) is too close to typical autoclave temperatures (average 250 F [121 C]) to ensure drug stability, according to the manufacturer. In addition, the flash point of propylene glycol is 210 F (99 C), which may make it combustible in an autoclave.30

A water-soluble, 10-mg/ml liquid ivermectin (Eqvalan—Merial) available for horses has been used safely when given orally.27 However, when this product was given intramuscularly, it resulted in the death of finches and budgerigars.27

Moxidectin

Pour-on or injectable moxidectin (Cydectin—Fort Dodge Animal Health) is also effective and available in 0.5% and 1% preparations, respectively. In one study, one or two topical treatments at 10-day intervals on the neck skin in budgerigars with 0.1 ml of the 10-mg/ml injectable was effective and showed no adverse effects in 30 birds.31 Pruritus disappeared within 10 days after the first treatment, while complete resolution of lesions took about 30 to 40 days, depending on lesion severity.31 In another study, two drops of a 1:20 dilution of 1% moxidectin applied topically to the neck once and then repeated 23 days later was effective in treating red-fronted parakeets.16 Spot-on 1,000 μg/ml moxidectin (Scatt—Vetafarm; 1 drop/30 g every 21 days for two or three treatments) has also been used with success and is popular among breeders and hobbyists.

Other antiparasitics

Avoid using older topical parasiticides, such as rotenone-orthophenylphenol (e.g. Goodwinol ointment), crotamiton (Eurax cream), and lindane, which may be more toxic than efficacious. In the past, applying mineral oil to the lesions has been effective, but it is messy and can result in side effects, including oily feathers and aspiration of the mineral oil. Cage mite protectors have no efficacy against Knemidocoptes species. Although selamectin (Revolution—Pfizer) is effective for treating ear mites (Otodectes species) and sarcoptic mange in mammalian species, it has not been evaluated in birds and is not recommended for use in avian species at this time.

Adjunctive management

Adjunctive therapy includes softening crusts with water-soluble, nontoxic emollients, such as aloe vera gel, being careful not to plug the nares. If the nares are occluded with crusts, carefully remove them to restore normal airflow. Sparing use of topical antibiotic ophthalmic ointments in and around the eyes may be needed in severe cases, but avoid contact with the feathers. Birds with open sores may benefit from concurrent administration of systemic antibiotics and nonsteroidal anti-inflammatory drugs (0.1 to 0.5 mg/kg meloxicam orally b.i.d.) as well as perch adjustments that make perching more comfortable for birds with foot and leg lesions. If indicated, the bird's diet should be improved and supplemental vitamin A may be beneficial.32

Breeding should be discontinued until the infestation is eliminated, and some individuals may need to be culled. Disinfect cages, roosts, and perches to prevent spread to other birds. If possible, perform a full medical work-up for underlying conditions because Knemidocoptes species infection is often secondary to other immunosuppressive disease processes.


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Source: VETERINARY MEDICINE,
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