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

该项目将开发一种精确的手持式护理点侧流免疫分析测试，用于检测患有约翰氏病（JD）的动物。JD是加拿大乳制品行业经济负担的四大疾病之一。JD对该行业的经济成本估计至少为每年9000万加元，其经济损失归因于牛奶产量减少、早期淘汰风险增加和屠宰时胴体重量减少。JD是由鸟分枝杆菌引起的。副肺结核（MAP），是一种慢性、进展缓慢、限制生产和潜在贸易壁垒的疾病。感染通常发生在犊牛摄入感染剂量的活MAP时，但慢性腹泻和严重消瘦的临床症状直到数年后才显现出来。患有临床前JD的动物看起来很健康，但可以在粪便中排出活的MAP，这是疾病传播的主要机制。由于缺乏治疗性抗生素，预防性疫苗和检测临床前疾病的测试，JD控制计划促进小牛卫生，识别和移除受感染的动物。在农业环境中有效管理JD迫切需要一种准确、快速的诊断测试，能够可靠地识别所有受感染的动物。目前还没有针对JD的血清学即时检测（POC）。由于缺乏在受感染动物中仅检测map特异性抗体的map特异性决定因素，POC测试的发展受到阻碍。申请人先前的研究鉴定了含有map特异性表位的蛋白质，这些蛋白质有可能作为准确map特异性诊断测试的基础。将对这些表位进行工程设计，以产生用于POC测试的试剂。分析开发将与行业合作伙伴Pro-Lab Diagnostics Inc.合作进行，Pro-Lab Diagnostics Inc.是体外诊断测试的领先制造商。POC测试在一次性试剂盒中组装，用户友好，只需要添加一滴样品（例如血液），并在几分钟内产生可见的彩色线反应结果。该测试将大大提高生产者管理JD的能力，并减少与牛奶产量和屠宰重量减少相关的损失。**************

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.**************