10150592Evaluation of an innovative assay for Johne's disease using North Wales herdsClosedGrant for R&DInnovate UKAlthough bovine TB in cattle has a very high profile, it is much less widespread than another disease caused by a mycobacterium, Johne's disease. Johne's, caused by _Mycobacterium avium_ paratuberculosis, is an infectious wasting disease which develops very slowly but statistically is present in around 70 % of herds (albeit perhaps in very few animals). The disease causes reductions in milk and beef yield; moreover, the organism is very difficult to kill by pasteurisation, and in principle can enter the food chain. There is some evidence that there are elevated levels of the Mycobacterium in Crohn's patients, and an on-going 'discussion' as to whether there is a causal link. Johne's disease is notifiable in many countries, but currently not in the UK; should it become notifiable, there would be a very major problem for UK agriculture. Not surprisingly, supermarkets are increasingly sourcing exclusively from 'Johne's free' herds. Many farmers are embracing this challenge and carrying out extensive testing of their animals. However, current assays available are very limiting. Fecal PCR or culture are widely used but only reliable in late stage disease - when there may be visible symptoms anyway. Commercial serological assays (using antigens to detect antibodies in serum) are also commonly used. However, although they give very few false positives, they reputedly pick up only around 20 % of the 'positive' animals. **Eradicating the disease requires earlier diagnosis.** Diagnostig have developed a serodiagnostic based on a set of unique proprietary synthetic molecules identical to cell wall components of the mycobacterium and have developed an assay which appears to detect infection earlier than the standard approaches, and which does so without interference by vaccination for Johne's disease or for bovine TB. This project will involve a real-time study using animals from local herds to compare the Diagnostig device with commercial serodiagnostics, and with PCR. Working closely with local farmers, and supported by NFU Cymru, samples will be provided, to correspond where possible with their routine sampling times, and evaluated in the Diagnostig assay using an established set of antigens. A robust analysis of results compared to those of standard assays will provide firm evidence that the new method, which uses a completely different approach to others, will provide farmers, and associations validating 'Johne's free' status, with a much better way of detecting, and therefore managing, early infections with Johne's disease.