Amplification of acidic protease virulence gene (aprV2) in samples from footrot lesions did not help in diagnosis of clinical virulent footrot in affected sheep flocks in New South Wales.

Although the apr2 gene could differentiate between benign and virulent strains of D. nodosus, the apr2 qPCR was of minimal use for field diagnosis of virulent footrot, where disease expression relies on host genetics, immunity and environmental conditions.