Ovine pulmonary adenocarcinoma (OPA), historically called jaagsiekte, is a contagious lung tumour of sheep caused by the jaagsiekte sheep retrovirus. The virus transforms secretory cells in the lung, producing slowly growing adenocarcinomas and large volumes of fluid. Affected sheep show progressive weight loss, exercise intolerance, and copious watery nasal discharge, classically demonstrated by the wheelbarrow test. The disease is invariably fatal and spreads through respiratory secretions within flocks.
Ovine pulmonary adenocarcinoma is a transmissible lung cancer of sheep caused by a retrovirus. It is a chronic, fatal wasting disease and an important cause of respiratory loss in flocks.
The jaagsiekte sheep retrovirus infects and transforms lung secretory cells, producing tumours. Transmission is mainly by inhalation of infectious respiratory fluid, often during close housing.
Affected sheep show gradual weight loss, increased respiratory effort, exercise intolerance, and abundant thin watery nasal fluid. Lowering the head can pour fluid from the nostrils (wheelbarrow test).
Clinical signs, the wheelbarrow test, and ultrasound of the chest support diagnosis; confirmation is by post-mortem examination and PCR for the virus, as there is no reliable blood test.
There is no cure. Affected animals should be culled to reduce spread and relieve suffering.
Control relies on culling clinical cases, sourcing replacements from low-risk flocks, reducing prolonged close housing, and ultrasound screening in valuable flocks.
This content is for educational purposes and is not a substitute for professional veterinary advice. If you are worried about your pet, contact your veterinarian.
