Air Sac Mites
BASICS
Definition: Arthropod parasite5 Sternostoma tracheocolum
Other Names: Tracheal Mite17,16 (this is the more appropriate name),28,5 Canary Lung Mite3
Disease Process: This is a common respiratory acariasis caused by parasites living in the trachea and syrinx28,5 and less commonly the bronchi, sinuses, and air sacs.17,3 The mites' complete lifecycle appears to occur on the bird,5 so transmission requires direct or close bird-to-bird contact,16 such as young becoming infected while being fed by their infected parents.5 Incubation period in Gouldians is 3 weeks, but may be longer in other species.5 Tracheal mites can seldom be a cause of sudden death or increased mortality in adult birds. Death results from bronchopneumonia and air sacculitis.3
Risk Factors: Concurrent infection with Enterococcus fecalis can occur.28,5
Contagious?: Contagious among susceptible birds in close or direct contact.
Other Names: Tracheal Mite17,16 (this is the more appropriate name),28,5 Canary Lung Mite3
Disease Process: This is a common respiratory acariasis caused by parasites living in the trachea and syrinx28,5 and less commonly the bronchi, sinuses, and air sacs.17,3 The mites' complete lifecycle appears to occur on the bird,5 so transmission requires direct or close bird-to-bird contact,16 such as young becoming infected while being fed by their infected parents.5 Incubation period in Gouldians is 3 weeks, but may be longer in other species.5 Tracheal mites can seldom be a cause of sudden death or increased mortality in adult birds. Death results from bronchopneumonia and air sacculitis.3
Risk Factors: Concurrent infection with Enterococcus fecalis can occur.28,5
Contagious?: Contagious among susceptible birds in close or direct contact.
CLINICAL DISEASE
Signalment: Mostly seen in Lady Gouldian finches29 and to a lesser extent canaries.28 May be present in other finches (e.g. Fringillidae, Estrildidae), but usually does not cause as severe of a disease.17,16,5 Can also occur in budgies and cockatiels.5 Signs are most severe in juvenile birds.16
Symptoms:
Symptoms:
- weight loss17
- loss of voice17,28,5
- cessation of singing28
- clicking sound17,3,5
- dyspnea (wheezing, gasping, open-mouth breathing)17,16,3,28,5
- tail-bobbing5
- +/- nasal discharge5
- weakness (severe cases)5
- head shaking28
- coughing17,16,3,5
- sneezing17,16,3,5
- death17,16,3,5 (low mortality rate)28
DIAGNOSIS
Differentials: Enterococcus faecalis and other bacterial causes of upper respiratory infection, poxvirus, Chlamydophila, Atoxoplasma, Trichomonas, Aspergillus, Syngamus3,28
Testing:
Testing:
- Transillumination of trachea with a bright light source may reveal the parasites17,29,5 (which appear as dark, pin-head sized spots, often moving).16,28,5 Wetting feathers over trachea with a small amount of alcohol may improve visualization.5,17 Not visualizing the parasites does not rule out their presence28--the burden may be low28 or the mites may be present be in the lower respiratory tract.5
- Mite eggs may be visible on microscopic exam of feces, sputum,5,16 or tracheal wash.5,17
- On necropsy, mites appear as black spots in mucus.17
TREATMENT
Immediate:
ivermectin3,5,16,17,29 (diluted 1:10 in propylene glycol and applied as one drop 'spot on' per bird up to 50g to the bare skin over the right jugular vein. CAUTION: this treatment has the potential to cause glycol toxicity)28
-OR-
doramectin 1:10 in sesame oil28
Repeat treatment in 7-10 days.28
All in-contact birds must be treated simultaneously.16
Long-term: Consider hanging a dichlorvos strip near (but out of reach of) the birds.3,5,28
-OR-
doramectin 1:10 in sesame oil28
Repeat treatment in 7-10 days.28
All in-contact birds must be treated simultaneously.16
Long-term: Consider hanging a dichlorvos strip near (but out of reach of) the birds.3,5,28
TYPICAL OUTCOME
Untreated birds may have a waxing-waning disease course with relapse after apparent recovery,5 with a low mortality rate due to asphyxiation.5 This disease tends to spread slowly through the entire flock.5
PREVENTION
Recognition of carriers with a low parasite burden is not possible.28 All newly acquired birds should be treated while in quarantine.28 Mite-free society finches may be used to foster gouldian eggs in order to produce mite-free flocks.5
CONSIDERATIONS
Other species of mite may affect other passerines (e.g. S. sialiphilus in Eastern Bluebirds).5
Suggested Reading:
Suggested Reading:
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