Ovine and Caprine Pulmonary Adenomatosis – NAVLE Study Guide
Overview and Clinical Importance
Ovine Pulmonary Adenomatosis (OPA), also known as Jaagsiekte (Afrikaans for "chasing sickness"), Ovine Pulmonary Adenocarcinoma, or Sheep Pulmonary Adenomatosis (SPA), is a contagious neoplastic lung disease of sheep and, rarely, goats. It is caused by the Jaagsiekte Sheep Retrovirus (JSRV), a betaretrovirus that induces malignant transformation of secretory epithelial cells in the distal respiratory tract.
OPA is considered one of the "iceberg diseases" of sheep (along with Johne's Disease, Maedi-Visna, Border Disease, and Caseous Lymphadenitis) because clinical cases represent only a small fraction of infected animals. The disease has significant economic impact in endemic regions and is invariably fatal once clinical signs appear.
Etiology
Causative Agent
Jaagsiekte Sheep Retrovirus (JSRV) is the etiological agent of OPA. It is classified as an exogenous betaretrovirus with the following characteristics:
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