Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, 615 N Wolfe St, Baltimore, MD, 21205, USA.
Perinatal HIV Research Unit, Nurses Residence, Chris Hani Baragwanath Academic Hospital, Soweto, South Africa.
BMC Infect Dis. 2018 Jul 4;18(1):299. doi: 10.1186/s12879-018-3193-7.
Efficient and effective strategies for identifying cases of active tuberculosis (TB) in rural sub-Saharan Africa are lacking. Household contact tracing offers a potential approach to diagnose more TB cases, and to do so earlier in the disease course.
Adults newly diagnosed with active TB were recruited from public clinics in Vhembe District, South Africa. Study staff visited index case households and collected sputum specimens for TB testing via smear microscopy and culture. We calculated the yield and the number of households needed to screen (NHNS) to find one additional case. Predictors of new TB among household contacts were evaluated using multilevel logistic regression.
We recruited 130 index cases and 282 household contacts. We identified 11 previously undiagnosed cases of bacteriologically-confirmed TB, giving a prevalence of 3.9% (95% CI: 2.0-6.9%) among contacts, a yield of 8.5 per 100 (95% CI: 4.2-15.1) index cases traced, and NHNS of 12 (95% CI: 7-24). The majority of new TB cases (10/11, 90.9%) were smear negative, culture positive. The presence of TB symptoms was not associated with an increased odds of active TB (aOR: 0.3, 95% CI: 0.1-1.4).
Household contacts of recently diagnosed TB patients in rural South Africa have high prevalence of TB and can be feasibly detected through contact tracing, but more sensitive tests than sputum smear are required. Symptom screening among household contacts had low sensitivity and specificity for active TB in this study.
在撒哈拉以南非洲农村地区，缺乏有效且高效的策略来发现活动性肺结核（TB）病例。家庭接触者追踪提供了一种诊断更多结核病病例的潜在方法，并能在疾病早期进行诊断。
从南非威姆贝区的公立诊所招募新诊断出的活动性肺结核成人患者。研究人员走访了索引病例家庭，并通过痰涂片显微镜检查和培养收集了用于结核病检测的痰标本。我们计算了发现一个额外病例所需的检出率和筛查的家庭数量（NHNS）。使用多水平逻辑回归评估家庭接触者中新发结核病的预测因素。
我们招募了 130 名索引病例和 282 名家庭接触者。我们发现了 11 例先前未确诊的细菌学确诊结核病病例，接触者中的患病率为 3.9%（95%CI：2.0-6.9%），检出率为 8.5/100（95%CI：4.2-15.1）索引病例，NHNS 为 12（95%CI：7-24）。大多数新的结核病病例（10/11，90.9%）为痰涂片阴性、培养阳性。TB 症状的存在与活动性结核病的发病风险增加无关（优势比：0.3，95%CI：0.1-1.4）。
在南非农村地区，最近诊断出的肺结核患者的家庭接触者中，TB 的患病率很高，通过接触者追踪可以方便地发现，但需要更敏感的检测方法。在本研究中，家庭接触者的症状筛查对活动性结核病的敏感性和特异性较低。
