Aspergillosis :

•  It is a disease caused by infection with genus Aspergillus.
• Manifestation of aspergillus depends upon which organs or system are involved and whether infection is localized or disseminated.
• It is usually confined to the lower pulmonary system with florid lesions in air sacs and lungs.
• In young poultry, it is referred to as brooder pneumonia .
• Other synonym :
• Fungal or mycotic pneumonia
• Pneumonomycosis
• Bronchomycosis

• Less manifestation related to infections of eye , brain , skin , joints and viscera.
• It usually means ‘pulmonary or respiratory aspergillosis’ .

Etiology :

    Two major species : Aspergillus fumigatus

                                   A . flavus

    Other :  A. terrus , A. glaucus , A. niger

• Organisms are common soil saprophytes occurring in decaying vegetable matter and feed grains.
• They grow on organic matter in warm humid environments .
• Spores are highly resistant to disinfectant .

Transmission :

• Infections are acquired from environmental exposure.
• Infection is by inhalation of spores that usually originate from infected eggs.
• Contamination of equipment may result in hatchery infection.
• Accidental breakage
• Entry through egg shell
• Contaminated feed or poultry house litter also produce infection.

Clinical signs :

• Biphasic mortality pattern

Acute form :

• Inappetance
• Weakness / lethargy
• Silent gasping
• Rapid breathing
• Thirst
• Drowsiness
• Nervous sign (rare)
• Loos or change in voice path

Chronic form :

• Ocular discharge (ocular form only )
• Wasting
• Torticollis

• Due to hatchery infection ( within first 3-5 days infection )

                      ⬇ 

Dyspnoea , polypnea, gasping ( open mouthed breathing – gaspers )

                      ⬇

                When these are associated with IB & ILT

                      ⬇

                           Gurgling and rattling noises   

                    [ In Aspergillus, usually no sounds ]

Postmortem lesion :

• Yellow to gray nodules or plaques in lung , air sac , trachea , plaque in peritoneal cavity, may have greenish surface.
• Conjunctivitis / keratitis
• Brain lesions may be seen in some birds with nervous signs.
• Air – filled cavities may appear green to black due to development of pigmented conidiophores.
• Brain : white to yellow circumscribed area either in cerebellum or cerebrum .

Microscopic :

• Air sacs : thickening due to massive infiltration of heterophil , multinucleated giant cells and other types of leukocytes.
• Germinating conidia are seen in membrane interstitium and lymphohistiocytic perivascular in less severely affected areas.
• Granuloma composing central necrotic cellular debris and heterophil with peripheral palisade of epithelioid macrophages and aggregates of lymphocytes .

Diagnosis :

• Clinical signs
• Lesions : white caseous nodules in lungs or air sacs

               Exudate plugs in tracheal and bronchial lumen.

• Demonstration of branched , septate Aspergillus hyphae in lesions.
• Confirmation should also be made by cultural isolation and identification of causative agents.
• Serological test ( limited value )

DDx :

From other respiratory disease by granulomatous lesions at  necropsy

a. Exudative fibrinous or purulent air sacculitis and pneumonia are frequently seen in :

• Mycoplasmosis
• Colibacilosis
• Fowl cholera
• Chlamydiosis
• Infectious bronchitis
• Newcastle disease
• Infectious laryngotracheitis

b. If granulomatous lesions predominate then

• Mycobacteriosis