Special Veterinary Pathology

ASPERGILLOSIS

Synonym : Brooder pneumonia, mycotic pneumonia

Definition

• Aspergillosis affects mainly poultry and occasionally in mammals characterized by dyspnoea, diarrhoea and granulomatous lesions caused by Aspergillus fumigatus and perhaps by the other species of Aspergillus.

Transmission

• Infection is by inhalation of spores
• Chicks may be hatched with infection since fungus can invade egg.
• The disease is common in chicks raised in brooder and hence the name 'brooder pneumonia'

Gross lesions

• In birds may be a diffuse pneumonia form and nodular pulmonary form or diffuse infection of air sacs.
• Besides respiratory tract, it may involve gastrointestinal tract, liver, spleen, kidney and ovaries
• In the lung, greyish multiple nodules surrounded by a zone of hyperaemia is seen.
• In the centre of the nodule, bluish material consisting of mycelia and fungal spores are observed
• The airsac is thickened with white mouldy growth

Microscopic lesions

• Granuloma with central caseation containing organisms and initial infilitration of neutrophils and macrophages and later by eosinophils, epithelioid cells and foreign body giant cells with fibrous capsule

Fungi-Black- Gomori’s Grocott stain

• Cattle: Lungs are usually nodular
• Placentitis in pregnant animals leading to abortion and the organisms can be isolated from the stomach of foetus.

Diagnosis

• Examination of contents of nodule and histological examination of tissue sections with special stains like Periodic acid schiff, demonstrating the club like conidiospores of A.fumigatus