Tuite Ashleigh R, Gallant Victor, Randell Elaine, Bourgeois Annie-Claude, Greer Amy L
Dalla Lana School of Public Health, University of Toronto, University of Toronto, Toronto, ON, Canada.
Harvard T.H. Chan School of Public Health, 1633 Tremont Street, Boston, MA, 02120, United States.
BMC Public Health. 2017 Jan 13;17(1):73. doi: 10.1186/s12889-016-3996-7.
In Canada, active tuberculosis (TB) disease rates remain disproportionately higher among the Indigenous population, especially among the Inuit in the north. We used mathematical modeling to evaluate how interventions might enhance existing TB control efforts in a region of Nunavut.
We developed a stochastic, agent-based model of TB transmission that captured the unique household and community structure. Evaluated interventions included: (i) rapid treatment of active cases; (ii) rapid contact tracing; (iii) expanded screening programs for latent TB infection (LTBI); and (iv) reduced household density. The outcomes of interest were incident TB infections and total diagnosed active TB disease over a 10- year time period.
Model-projected incidence in the absence of additional interventions was highly variable (range: 33-369 cases) over 10 years. Compared to the 'no additional intervention' scenario, reducing the time between onset of active TB disease and initiation of treatment reduced both the number of new TB infections (47% reduction, relative risk of TB = 0.53) and diagnoses of active TB disease (19% reduction, relative risk of TB = 0.81). Expanding general population screening was also projected to reduce the burden of TB, although these findings were sensitive to assumptions around the relative amount of transmission occurring outside of households. Other potential interventions examined in the model (school-based screening, rapid contact tracing, and reduced household density) were found to have limited effectiveness.
In a region of northern Canada experiencing a significant TB burden, more rapid treatment initiation in active TB cases was the most impactful intervention evaluated. Mathematical modeling can provide guidance for allocation of limited resources in a way that minimizes disease transmission and protects population health.
在加拿大，原住民中活动性结核病（TB）发病率仍然高得不成比例，尤其是北部的因纽特人。我们使用数学模型来评估干预措施如何加强努纳武特地区现有的结核病控制工作。
我们开发了一个基于主体的结核病传播随机模型，该模型捕捉了独特的家庭和社区结构。评估的干预措施包括：（i）对活动性病例进行快速治疗；（ii）快速接触者追踪；（iii）扩大潜伏性结核感染（LTBI）筛查项目；（iv）降低家庭密度。感兴趣的结果是10年期间的结核病感染发病率和确诊的活动性结核病总数。
在没有额外干预措施的情况下，模型预测的发病率在10年内变化很大（范围：33 - 369例）。与“无额外干预”情景相比，缩短活动性结核病发病至开始治疗的时间，既减少了新的结核病感染数量（减少47%，结核病相对风险 = 0.53），也减少了活动性结核病的诊断数量（减少19%，结核病相对风险 = 0.81）。扩大普通人群筛查预计也会减轻结核病负担，尽管这些结果对家庭外传播相对量的假设很敏感。模型中研究的其他潜在干预措施（学校筛查、快速接触者追踪和降低家庭密度）效果有限。
在加拿大北部一个结核病负担较重的地区，对活动性结核病病例更快地开始治疗是评估的最有效干预措施。数学模型可以为有限资源的分配提供指导，以尽量减少疾病传播并保护人群健康。
