Point-of-care lateral flow immunoassay for rapid diagnosis of Johne's disease in cattle

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This project will develop an accurate, handheld point-of-care Lateral Flow Immunoassay test for detection of animals with Johne's disease (JD). JD is one of four top diseases of economic burden to the Canadian dairy industry. The economic cost of JD to this sector is estimated to be at least C$90M annually, with the financial losses attributed to reduction in milk production, increased risk for early culling, and reduced carcass weight at slaughter. JD is caused by the bacterium Mycobacterium avium ssp. paratuberculosis (MAP), and is a chronic, slow progressing, production limiting and potential trade barrier disease. Infection normally occurs when calves ingest an infectious dose of live MAP, but clinical symptoms of chronic diarrhea and severe emaciation do not become apparent until years later. Animals with preclinical JD look healthy but can shed live MAP in their feces which is the primary mechanism for disease transmission. Given the lack of curative antibiotics, preventative vaccines and tests that detect preclinical disease, JD control programs promote calf hygiene, identification and removal of infected animals. Effective management of JD in an agricultural setting urgently requires an accurate, rapid diagnostic test that can reliably identify all infected animals. Currently there is no serological point-of-care (POC) test available for JD. The development of POC tests has been hampered by the lack of MAP-specific determinants that detect only MAP-specific antibodies in infected animals. Previous research by the applicant identified proteins containing MAP-specific epitopes that have the potential to serve as the basis of an accurate MAP-specific diagnostic test. These epitopes will be engineered to generate reagents for the POC tests. Assay development will be conducted in collaboration with industry partner Pro-Lab Diagnostics Inc., a leading manufacturer of in vitro diagnostic tests. The POC test is assembled in a disposable kit, is user friendly, requires only the addition of a drop of sample (e.g. blood) and produces results that are visible as coloured-line reaction within minutes. The test will greatly enhance producer's ability to manage JD and reduce the losses associated with reduced milk production and slaughter weight.**************