Development of a rapid cost effective test for ovine Johne's Disease based on testing of pooled faeces : final report.

Abstract

This project was undertaken to develop and evaluate a rapid, cost-effective, flock test for Mycobacterium paratuberculosis in pooled faecal samples, based on hybridisation-capture polymerase chain reaction (HC-PCR). However, a simpler direct technique (DPCR) was found to be more sensitive than HC-PCR. About 67% of culture positive pooled faecal samples were positive when tested using DPCR. In a blind trial, 83% of 12 farms identified by culture of pooled faecal samples were detected using DPCR. The cost of DPCR is no greater than that of other flock detection strategies. The test is suitable for use in the National Ovine Johne’s Disease Control and Evaluation Program. A constraint exists in that Veterinary Committee does not recognise the results of DNA-based tests for M. paratuberculosis as being definitive. The costs of follow-up testing to confirm infection are high. Recommendations are made to improve the test and reduce its cost.