Special Veterinary Pathology

JAAGSIEKTE

Synonyms

• Ovine pulmonary adenoma, Ovine pulmonary adenomatosis, Pulmonary carcinoma of sheep

Definition

• It is a neoplastic disease of older sheep. The affected animals show dyspnoea after exercise

Incidence

• First Reported in South Africa. Reported in various parts of India

Etiology

• Type D oncovirus (a retrovirus)

Transmission

• Droplet infection from respiratory secretions, close contact

Pathogenesis

• Entry of virus
• Replication of virus in type II pneumocytes in alveoli
• Transformation of type II pneumocytes & Clara cells in terminal bronchioles
• Intra alveolar and intra bronchiolar, polypoid ingrowths
• Copious production of mucus
• Excessive surfactant like protein is produced in tumour
• Causing accumulation of macrophages
• Adenomatous ingrowths of alveolar epithelium encroach in alveolar lumen
• Death due to anoxia

Clinical signs

• Incubation period – 1-3 years
• Age affected – 3-4 years of age
• Coughing and panting after exercise
• Emaciation, dyspnoea, lacrymation
• Profuse watery discharge from nostrils
• Death 6 weeks to 4 months
• Moist crackles produced over the lungs
• No fever
• Pasteurellosis is a common complication

Lesions

• Multiple foci of neoplastic alveolar type II cells in acinar and papillary patterns
• Adenocarcinoma of lungs
• Mononuclear cells and neutrophils in bronchial lymphnodes

Diagnosis

• Jaagsiekte – Large amount of catarrhal nasal discharge which is characteristic of the disease
• Wheel barrow test – Hold the sheep up by hind legs, watery mucus runs out of the nostrils
• Histopathology of lungs and polymerase chain reaction