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Aspergillosis

Bronchomycosis, Pneumomycosis

Aspergillosis is an infectious, non-contagious common fungal disease of chickens. The disease is caused by infection with species belonging to the Aspergillus genus. Aspergillus fumigatus is the most common species isolated from infected birds, followed by A. flavus. There are two different forms of the disease---consisting of acute or chronic form.
  • Acute form: The acute form, also referred to as Brooder pneumonia causes respiratory disease in newly hatched chicks and is associated with high morbidity and high mortality rates.
  • Chronic form: The chronic form, which is the discussed on this page, usually affects older chickens. It primary causes respiratory disease, but the organism can spread to the brain and eye causing neurological signs and blindness.
Clinical Signs
Clinical signs may include coughing, loss of the ability to vocalize (caused by mucus accumulation in the trachea), and open-mouth breathing. When the eyes are infected, it may cause cloudy eyes, eye swelling, and blindness. If the central nervous system is affected, torticollis may be observed. Other generalized signs of illness include lethargy, weight loss, laying down frequently, isolation from the group, and loss of appetite.

Where the fungus is found
Aspergillus spp. are naturally found in small concentrations throughout the environment---in the air, soil, bedding, etc. Higher amounts of Aspergillus spp. develop through the presence of dust and mold.

How it spreads
Aspergillosis is not a transmissible disease. Chickens are infected through environmental exposure. Aspergillus are opportunistic invaders, and healthy birds are usually resistant to infection unless they are exposed to a massive number in the environment or are vulnerable due to age, concurrent illness, chronic inflammatory condition (such as bumblefoot or other prolonged condition) or stress. Sometimes multiple flock members become infected at the same time from exposure to the same source.

Symptoms

Loss of or reduction in vocalizing
Difficulty breathing
Open-mouthed breathing
Tail bobbing
Audible respiratory sounds
Abnormal crackles or clicking noises
Nasal discharge
Increased thirst
Reduced appetite
Weight loss
Lethargy
Increased time spent laying down
Isolation from flock members
Green color in urates in feces

Diagnosis

  • History - of a previous stressful event, an immunosuppressive disease or treatment and/or exposure to spore-laden environment.
  • Complete blood count (CBC)
  • Fungal culture - taken of the throat, trachea or air sacs
  • Cytology
  • Endoscopy
  • Histopathology
  • Postmortem exam - Often based on observation of white caseous nodules in th

Treatment

MethodDetails
Supportive careIsolate the bird from the flock and place in a safe, comfortable, warm location (your own chicken "intensive care unit") with easy access to water and food. Limit stress. Call your veterinarian.
Itraconazole10 mg/kg administered orally, twice a dayK Marx
Amphotericin B1 mg/kg administered IT, TID + 1.5 mg/kg IVK Marx
Ketoconazole60 mg/ml
Tarwood (Loxostylis alata) extract200 mg/kgM Suleiman, N Duncan, J Eloff, V Naidoo
Ant. Tartrate30C once a day for 3 daysK. Glos 2015
Drosera rotundfolia30C once a day for 3 daysK. Glos 2015

Prevention

  • Minimizing use of antibiotics and corticosteroids
  • Provide good ventilation and a balanced diet
  • Do not overcrowd birds
  • Daily removal of any leftover uneaten feed and/or decaying vegetable or fruit matter
  • Inspecting feed regularly for signs of mold, do not feed to birds if suspected.
  • Place feeders and waterers on screened, elevated platforms to prevent birds from picking up molds that develop in those areas.
  • Daily cleaning and disinfection of feeders and waterers
  • Do not expose birds to moldy straw or hay
  • Frequently move feeders and water dispensers to different areas to prevent fertile areas for growth of mold
  • Conduct regular air quality tests
  • Clean any mold present off hard surfaces with water and detergent, and dry completely. Absorbent materials such as ceiling tiles, that are moldy, should be replaced.
  • Reduce the potential for condensation on cold surfaces (i.e., windows, piping, exterior walls, roof, or floors) by adding insulation.

Prognosis

Treatment is usually long-term, frustrating, and often unrewarding if the disease is not recognized until the later stages of the infection. Early treatment is essential for a postive outcome.

Scientific References

Good Overviews

Risk Factors

  • Exposure to damp, dusty, moldy, or poorly ventilated areas
  • Repeated or prolonged use of antibiotics
  • Steroid use, even for a short period of time
  • Weakened immune system
  • Keeping chickens indoors, without any outdoor access
  • Shipping or relocating birds
  • Exposure to respiratory irritants (such as disinfectant fumes, cigarette smoke and/or ammonia)
  • Very young or older chickens
  • Using organic substances for bedding such as corn cob or hay.
  • Poor sanitation, leading to accumulation of old, moist food or bedding or droppings
  • Stressors such as malnutrition, attempted predator attacks, fighting among flock members, exposure to very cold or hot temperatures