The persistence of tuberculosis today and its global disparity send a powerful message that effective tuberculosis control must respond to its regional epidemiology. Active case finding through contact investigation is a standard protocol used for tuberculosis control, but its effectiveness has not been established especially in endemic areas. To quantify the potential effectiveness of contact investigation in Kampala, Uganda, we used a cross-sectional design to evaluate the social networks of 123 tuberculosis index cases and 124 controls without tuberculosis. Tuberculous infection was present in 515 of 989 tuberculosis case contacts (52.1%) and 396 of 1,026 control contacts (38.6%; adjusted prevalence ratio = 1·4, 95% CI: 1.3, 1.6). The proportion of infected participants with known exposure within the social network of tuberculosis case was 35%. The population attributable fraction was 11.1% for any known exposure with 7.3% attributable to household exposure and 3.4% attributable to extra-household exposure. This low population attributable fraction indicates that contact tracing in the social networks of index cases will have only a modest effect in reducing tuberculous infection in a community. New approaches to community-level active case finding are needed.

中文翻译：

---

非洲城市社区结核病病例社交网络暴露导致结核分枝杆菌感染

当今结核病的持续存在及其全球差异发出了一个强有力的信息：有效的结核病控制必须对其区域流行病学作出反应。通过接触者调查主动发现病例是结核病控制的标准方案，但其有效性尚未确定，特别是在流行地区。为了量化乌干达坎帕拉接触者调查的潜在有效性，我们采用横断面设计来评估 123 名结核病指数病例和 124 名无结核病对照者的社交网络。 989 名结核病病例接触者中有 515 名（52.1%）存在结核感染，1,026 名对照接触者中有 396 名存在结核感染（38.6%；调整后患病率 = 1·4，95% CI：1.3，1.6）。在结核病病例社交网络中已知接触过的感染者比例为 35%。对于任何已知暴露，人口归因分数为 11.1%，其中 7.3% 归因于家庭暴露，3.4% 归因于家庭外暴露。这种低人口归因分数表明，在指示病例的社交网络中进行接触者追踪对于减少社区结核感染的影响有限。需要新的方法来进行社区层面的主动病例发现。