Sheep Pulmonary Adenomatosis



Antigenicity

  • The virus cannot be grown in culture, although it can be seen by EM on tumor cells of infected sheep

Pathogenesis

  • Causes a proliferation of alveolar lining cells, producing massive amounts of fluid
  • Proliferative foci project into alveoli and bronchi and from slow-growing tumors
  • Death occurs between 3-4 years of age

Clinical signs:

  • Low exercise tolerance
  • Gradual weight loss
  • Dyspnoea
  • Coughing
  • Nasal fluid discharges during wheelbarrow test
  • Secondary bacterial infection by Pasteurella hemolytica often precipitates death
  • PM reveals fawn-gray tumor (for more see here)

Epidemiology

  • Found in 25% of pneumonia cases in Scotland
  • Absent in USA, common in UK

Diagnosis

  • Electron microscopy on lung biopsy

Control

  • Cull clinically affected animals



  • Also called pulmonary carcinomatosis
  • Infectious bronchiolar-alveolar carcinoma caused by a retrovirus
  • Commonest under intensive management systems which favour aerosol transmission and close contact of disease
  • Behaves like chronic pneumonia
  • Takes months to years to express itself clinically as coughing and exercise intolerance
  • Gross pathology:
    • Heavy lungs which fail to collapse
    • The lesions progress from small firm grey/white nodular lesions to extensive confluent areas with replacement by neoplastic tissue
    • Cut surface oozes fluid
    • There is often coexistent infection present
    • Occasional metastases to bronchial and mediastinal lymph nodes can occur
  • Histopathology:
    • Widespread proliferation of alveolar (Type 2) and terminal bronchiolar epithelium, lining the alveoli and lower airways
    • Multiple neoplastic foci of cuboidal/columnar cells forming papillary projections into the lumen
    • Metastases of the same in the bronchial and mediastinal lymph nodes
  • There is no serological test, and diagnosis depends upon raising the animal by the hind limbs whereupon a clear fluid issues from the nose = "Wheelbarrow test"
  • More information