Exotic Diseases

Return to Exotic Diseases Index

Click on the images on this page to see a larger image and more information

Species Infected

primarily sheep

reported in goats

Clinical Signs

• incubation from 6 months to 3 years
• in endemic flocks usually seen in sheep older than 3 years
• occasional cough/pant after exercise
• weight loss
• development of a profuse frothy nasal discharge
• if animal held by hindquarters up to 200 ml of fluid can be collected
• moist rales
• no elevated temperature
• appetite normal
• death in 2-6 months
• mortality 2-8%

Lesions

• confined to thorax
• lungs grossly enlarged up to 3 times normal weight
• small to large firm greyish neoplastic-like nodules
• most extensive in anterior lobes
• may have metastases to local lymphnodes
• excess of foamy fluid in airways
• may have pleural adhesions and/or secondary pneumonias
• not infrequent to have maedi lesions present
• histologically: adenomatous metaplasia of alveolar epithelium forming tumour-like masses

Aetiology

• Lentivirus (Retroviridae)
• not related to maedi-visna virus

Pathogenesis

• unknown
• death by anoxic anoxia
• no inflammation or toxaemia is involved

Epidemiology

• disease is spread by inhalation
• most prevalent in intensively housed sheep but is also found on range properties
• vertical transmission has been reported but its importance is obscure

Differential Diagnoses

     1.  maedi
     2.  verminous pneumonia
     3.  lymphoma