Ovine pulmonary adenocarcinoma

A detailed overview of Ovine Pulmonary Adenocarcinoma

Ovine Pulmonary Adenocarcinoma

Ovine Pulmonary Adenocarcinoma (OPA), also known as Jaagsiekte, is a contagious lung tumor found in sheep. It is caused by the Jaagsiekte sheep retrovirus (JSRV), which induces the formation of tumors in the lungs of affected animals. This disease is of significant concern in the field of veterinary medicine due to its impact on sheep farming and animal health.

Etiology

OPA is caused by the Jaagsiekte sheep retrovirus, a betaretrovirus that integrates into the host's genome. The virus is transmitted primarily through respiratory secretions, making close contact between animals a significant risk factor for the spread of the disease.

Pathogenesis

Once the virus infects the lung tissue, it induces the transformation of alveolar and bronchiolar epithelial cells, leading to the development of adenocarcinoma. The tumors primarily affect the alveoli, causing respiratory distress and reduced lung function.

Clinical Signs

Affected sheep typically exhibit signs of respiratory distress, including dyspnea, coughing, and nasal discharge. As the disease progresses, weight loss and exercise intolerance become more pronounced. In advanced cases, affected animals may develop a characteristic "wheelbarrow test" positive result, where fluid is expelled from the nostrils when the animal's hindquarters are elevated.

Diagnosis

Diagnosis of OPA is challenging due to the lack of specific clinical signs in early stages. Ultrasound and radiography can be used to detect lung masses, but definitive diagnosis often requires histopathological examination of lung tissue. Polymerase chain reaction (PCR) tests can detect JSRV DNA in tissue samples.

Treatment and Control

There is currently no effective treatment for OPA. Control measures focus on preventing the spread of the virus through biosecurity practices, such as isolating affected animals and maintaining closed flocks. Selective breeding for resistance is also being explored as a long-term strategy.

Economic Impact

OPA can have a significant economic impact on sheep farming due to reduced productivity, increased morbidity, and mortality. The disease can lead to substantial financial losses for farmers due to decreased wool and meat production.

Research

Ongoing research aims to better understand the molecular biology of JSRV and the host's immune response to infection. Advances in genomics and proteomics are providing new insights into potential targets for vaccine development and therapeutic interventions.

Related pages

• Sheep diseases
• Retrovirus
• Veterinary pathology

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  Jaagsiekte