Epidemiologic Inference From the Distribution of Tuberculosis Cases in Households in Lima, Peru
Epidemiologic Inference From the Distribution of Tuberculosis Cases in Households in Lima, Peru
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DOI：
10.1093/infdis/jir162
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发表时间：
2011-06-01
影响因子：
6.4
通讯作者：
Murray, Megan B.
中科院分区：
文献类型：
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作者：
Brooks-Pollock, Ellen;Becerra, Mercedes C.;Murray, Megan B.
背景结核病（TB）通常发生在活动性TB患者的家庭接触者中。目前尚不清楚聚集性病例是否代表家庭传播或结核病的共同家庭风险因素。我们使用来自秘鲁利马764个家庭的横断面数据来估计家庭和社区传播的相对贡献、病例之间的平均时间以及先前结核病感染所提供的免疫力。每个家庭的病例分布情况表明，10个非指标家庭病例中几乎有7个是在社区而不是在家庭中感染的。家庭病例之间的平均间隔为3.5年。我们观察到每个家庭病例数的饱和效应，并估计保护性免疫可使疾病风险降低35%。横断面家庭数据可以阐明结核病的自然史和传播动态。在这种高发病率的情况下，我们发现大多数病例可归因于社区传播，病例患者的家庭接触者从家庭暴露中获得了一些免疫力。对家庭接触者进行筛查，如果持续数年，可能是发现新结核病例的有效方法。
Background. Tuberculosis (TB) often occurs among household contacts of people with active TB. It is unclear whether clustering of cases represents household transmission or shared household risk factors for TB.Methods. We used cross-sectional data from 764 households in Lima, Peru, to estimate the relative contributions of household and community transmission, the average time between cases, and the immunity afforded by a previous TB infection.Results. The distribution of cases per household suggests that almost 7 of 10 nonindex household cases were infected in the community rather than in the household. The average interval between household cases was 3.5 years. We observed a saturation effect in the number of cases per household and estimated that protective immunity conferred up to 35% reduction in the risk of disease.Conclusions. Cross-sectional household data can elucidate the natural history and transmission dynamics of TB. In this high-incidence setting, we found that the majority of cases were attributable to community transmission and that household contacts of case patients derive some immunity from household exposures. Screening of household contacts may be an effective method of detecting new TB cases if carried out over several years.