Human adaptation and transmissibility of Mycobacterium tuberculosis genetic lineages. A genomic epidemiology study to guide TB control

结核病（TB）的主要病原体结核分枝杆菌（Mtb）每年造成的死亡人数超过任何其他单一感染病原体。结核分枝杆菌被分为八个遗传谱系，初步数据支持它们之间的毒力和传播性差异。在全球范围内，结核分枝杆菌谱系显示出与人类亚群相似的独特地理格局，表明宿主和病原体之间存在共同适应。目前尚不清楚这种地理模式是否会在不同人类亚群生活得很近的世界性社会中继续观察到，并且结核分枝杆菌谱系有机会感染没有共同适应的“幼稚”宿主。评估结核分枝杆菌谱系是否和为什么具有可变的传播率，以及它们是否确实适应不同的人类亚群，可以帮助指导疾病控制，并提高我们对生物宿主病原体关系的理解。利用来自国际联盟的流行病学和全基因组测序数据，该项目旨在调查结核分枝杆菌谱系与人类亚群之间和内部疾病传播性之间的关系。将采用全基因组关联方法来精细绘制与遗传表型相关的特定结核分枝杆菌遗传位点。研究结核分枝杆菌与其人类宿主之间的适应性将确定结核分枝杆菌谱系和宿主祖先最容易进展和传播的组合。这最终有助于完善潜伏性结核病化学预防和有针对性的接触者追踪等疾病控制战略，以实现世卫组织到2035年消除结核病的终止结核病目标。

The main causative agent of tuberculosis (TB), Mycobacterium tuberculosis (Mtb), is responsible for more deaths annually than any other single infectious agent. Mtb bacteria are separated into eight genetic lineages and preliminary data supports differences in virulence and transmissibility among them. Globally, Mtb lineages show distinct geographical patterns that parallel that of human subpopulations suggesting co-adaption between host and pathogen. It is unknown if this geographic pattern will continue to be observed in cosmopolitan societies where different human subpopulations live in close proximity, and Mtb lineages have the opportunity to infect ‘naive’ hosts without co-adaptation. Assessing if and why Mtb lineages have variable transmissibility and if they are indeed adapted to different human subpopulations can help guide disease control and improve our understanding of biological host pathogen relationships. Using epidemiological and whole genome sequencing data from an international consortium, this project aims to investigate the relationship between Mtb lineage and disease transmissibility across and within human subpopulations. A genome wide association approach will be employed to fine map specific Mtb genetic loci associated with the transmissibility phenotype. Investigating adaptation between Mtb and its human host will define combinations of Mtb lineage and host ancestry most prone to progression and transmission. This can ultimately help refine disease containment strategies such as latent TB chemoprophylaxis and targeted contact tracing to achieve WHO End TB goals of eliminating TB by 2035.