OPA disease test for sheep on horizon

A test to diagnose ovine pulmonary adenocarcinoma (OPA) before signs of disease appear could be available in a few years, which could save sheep farmers from significant economic losses –  particularly when high-value breeding rams are affected – and improve animal welfare.

This incurable and fatal disease infects the lungs of sheep, triggering large tumour growth causing excessive fluid production. Early diagnosis of OPA in lambs would improve the control strategy and limit the spread of disease, which currently happens as farmers purchase infected, but apparently healthy, sheep.

For the first time, and contrary to what had been thought, David Griffiths, a scientist at Moredun, found sheep can produce an immune response to OPA. “The advanced screening process has found 40% of animals tested did produce antibodies to the virus,” he said.

This information has been used by scientists to develop a flock test. However, it is not suitable for early- stage testing because not enough of the virus is in the blood, as it is confined to the lungs.

“By focusing on the biology of the disease and identifying early stages before clinical signs, there are new opportunities to pursue. A diagnostic test is attainable, although a vaccine is still a while away,” said Dr Griffiths.

Moredun would like to hear from farmers with affected sheep. Get in touch on 0131 445 5111.

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