Potential application of emerging diagnostic techniques to the diagnosis of bovine Johne's disease (paratuberculosis)

- Mycobacterium avium subspecies paratuberculosis (MAP) causes a chronic wasting disease in adult cattle.
- Identification of earlier MAP infection stages is challenging using currently available tests.
- Emerging diagnostic techniques display promise to complement and enhance future MAP control.
- Routine application of many of these novel technologies will require the development of multiplex assays and cheaper test formats.

Mycobacterium avium subspecies paratuberculosis (MAP) causes Johne's disease (paratuberculosis), a chronic wasting disease in cattle with important welfare, economic and potential public health implications. Current tests are unable to recognise all stages of the disease, which makes it difficult to diagnose and control. This review explores emerging diagnostic techniques that could complement and enhance the diagnosis of MAP infection, including bacteriophage analysis, new MAP-specific antigens, host protein expression in response to infection, transcriptomic studies, analysis of microRNAs and investigation of the gastrointestinal microbiome. It emphasises the inherent challenges of diagnosing bovine Johne's disease and investigates novel areas which may have the potential both to advance our understanding of the immunopathology of MAP infection and to augment current diagnostic tests.