Molecular Epidemiology of Leprosy

描述（由申请人提供）：2002年新发现67万麻风病病例。在过去的10-20年里，世界卫生组织实施的有效的多药治疗一直用于治疗麻风病患者，但造成这种高发病率的因素是什么？对于麻风病，致病生物麻风分枝杆菌的潜在传播机制在来源、宿主、传播方式和与宿主的相互作用方面仍不清楚。存在多种假设，但由于无法在体外培养麻风分枝杆菌，疾病发病缓慢，临床表现广泛，答案仍然是推测性的。最近获得的麻风分枝杆菌分离株基因组序列是适用于麻风流行病学的宝贵新资源。该建议提出了一种独特的方法，旨在共同努力研究多种因素，以便更全面地了解麻风病持续发病的最合理原因。目标是通过开发和应用敏感、特异和简单的分子方法来推进几个独立实验室的研究工作。具体目标是：1。通过土壤和水体中麻风分枝杆菌特异性DNA和mRNA的PCR扩增，评价人外环境对麻风传播的贡献；b)菌株分型，与流行地区的临床菌株进行比较；2. 通过麻风分枝杆菌特异性DNA和mRNA的PCR扩增，评价麻风接触者亚临床感染情况；B)菌株分型，与指示病例的临床菌株进行比较；c)感染和免疫相关细胞因子mRNA的表达；和3。通过麻风分枝杆菌特异性DNA和mRNA的PCR扩增，评价麻风发病的贡献；B)菌株分型以便与流行病学相关病例进行比较；c)鉴定由folP和rpoB基因突变引起的原发性和获得性耐药，分别是氨苯砜和利福平的靶点。通过菌株分型方法证明麻风分枝杆菌在传播链中的同一性是很重要的。应用9个新发现的多态性位点进行菌株分型是这一建议的关键组成部分。预计从这项研究投资中产生的实际解决办法和知识数据库将对麻风监测和控制最流行地区的传播以及关于麻风分枝杆菌的毒力、进化和致病性的研究产生切实影响。

DESCRIPTION (provided by applicant): 670,000 new cases of leprosy were detected during the year 2002. What are the factors that contributed to this high incidence even though effective multidrug therapy implemented by the World Health Organization has been used to treat leprosy patients over the last 10-20 years? For leprosy, the underlying mechanisms of transmission of Mycobacterium leprae, the causative organism, are still unclear with respect to the source, reservoir, mode of transmission and interaction with the host. Multiple hypotheses exist, but answers remain speculative owing to the inability to cultivate M. leprae in vitro, the slow onset of disease, and the broad spectrum of clinical manifestations. The recent availability of the genome sequence of an isolate of M. leprae is a valuable new resource applicable to the epidemiology of leprosy. This proposal presents a unique approach aimed at a concerted effort to study multiple factors in order to obtain a more comprehensive understanding of the most plausible causes for continued incidence of leprosy. The objectives are to advance the research endeavors at several independent laboratories through development and application of sensitive, specific and simple molecular methods. The specific aims are: 1.To evaluate the contribution of the extra-human environment in leprosy transmission by: a) PCR amplification of M. leprae specific DNA and mRNA in soil and water; and b) strain typing for comparison with clinical strains found in the endemic region; 2. To evaluate sub-clinical infections in contacts of leprosy patients by: a) PCR amplification of M. leprae specific DNA and mRNA; b) strain typing for comparison with clinical strains found in index cases; and c) demonstration of mRNA of cytokines involved in infection and immunity; and 3. To evaluate the contribution of incident leprosy cases by: a) PCR amplification of M. leprae specific DNA and mRNA; b) strain typing for comparison with epidemiologically linked cases and; c) identification of primary and acquired drug resistance conferred by mutations in folP and rpoB genes, targets of dapsone and rifampicin respectively. It is important to prove identity of M. leprae within the chain of transmission by strain typing methods. The application of nine newly discovered polymorphic loci for strain typing is a key component of this proposal. It is envisioned that the practical solutions and the knowledge database that will emerge from this research investment will have a tangible impact on leprosy surveillance and control of transmission in the most endemic areas and to studies regarding virulence, evolution and pathogenicity of M. leprae.