Department of Health Policy and Management, Yale School of Public Health, 60 College Street, New Haven, CT, 06510, USA.
Peraton, 2800 Century Pkwy NE, Atlanta, GA, USA.
Sci Rep. 2022 Apr 26;12(1):6780. doi: 10.1038/s41598-022-10488-2.
Mycobacterium tuberculosis transmission dynamics in high-burden settings are poorly understood. Growing evidence suggests transmission may be characterized by extensive individual heterogeneity in secondary cases (i.e., superspreading), yet the degree and influence of such heterogeneity is largely unknown and unmeasured in high burden-settings. We conducted a prospective, population-based molecular epidemiology study of TB transmission in both an urban and rural setting of Botswana, one of the highest TB burden countries in the world. We used these empirical data to fit two mathematical models (urban and rural) that jointly quantified both the effective reproductive number, [Formula: see text], and the propensity for superspreading in each population. We found both urban and rural populations were characterized by a high degree of individual heterogeneity, however such heterogeneity disproportionately impacted the rural population: 99% of secondary transmission was attributed to only 19% of infectious cases in the rural population compared to 60% in the urban population and the median number of incident cases until the first outbreak of 30 cases was only 32 for the rural model compared to 791 in the urban model. These findings suggest individual heterogeneity plays a critical role shaping local TB epidemiology within subpopulations.
在高负担环境中，结核分枝杆菌的传播动力学了解甚少。越来越多的证据表明，传播可能具有广泛的个体异质性（即超级传播者），但这种异质性的程度和影响在高负担环境中很大程度上是未知和未测量的。我们在博茨瓦纳的城市和农村地区进行了一项前瞻性、基于人群的结核分枝杆菌传播分子流行病学研究，博茨瓦纳是世界上结核病负担最高的国家之一。我们使用这些经验数据拟合了两个数学模型（城市和农村），这些模型共同量化了每个人群中的有效繁殖数[Formula: see text]和超级传播的倾向。我们发现城市和农村人群都具有高度的个体异质性，但这种异质性对农村人群的影响不成比例：99%的继发传播归因于农村人群中仅 19%的传染性病例，而城市人群中这一比例为 60%，农村模型中直到第一次出现 30 例的新发病例中位数仅为 32 例，而城市模型中为 791 例。这些发现表明，个体异质性在塑造亚人群中的局部结核病流行病学方面起着关键作用。
