Division of Infectious Diseases, Duke University Medical Center, Durham, North Carolina.
Department of Epidemiology, University of North Carolina Gillings School of Global Public Health, Chapel Hill, North Carolina.
Am J Trop Med Hyg. 2019 Dec;101(6):1416-1423. doi: 10.4269/ajtmh.19-0558.
Community-based active case detection of malaria parasites with conventional rapid diagnostic tests (cRDTs) is a strategy used most commonly in low-transmission settings. We estimated the sensitivity of this approach in a high-transmission setting in Western Kenya. We tested 3,547 members of 912 households identified in 2013-2014 by index children with (case) and without (control) cRDT-positive malaria. All were tested for with both a cRDT targeting histidine-rich protein 2 and with an ultrasensitive real-time polymerase chain reaction (PCR). We computed cRDT sensitivity against PCR as the referent, compared prevalence between participant types, and estimated cRDT detectability as a function of PCR-estimated parasite density. Parasite prevalence was 22.9% by cRDTs and 61.5% by PCR. Compared with children aged < 5 years or adults aged > 15 years, geometric mean parasite densities (95% CI) were highest in school-age children aged 5-15 years (8.4 p/uL; 6.6-10.6). The overall sensitivity of cRDT was 36%; among asymptomatic household members, cRDT sensitivity was 25.5% and lowest in adults aged > 15 years (15.8%). When modeled as a function of parasite density, relative to school-age children, the probability of cRDT positivity was reduced in both children aged < 5 years (odds ratio [OR] 0.48; 95% CI: 0.34-0.69) and in adults aged > 15 years (OR: 0.35; 95% CI: 0.27-0.47). An HRP2-detecting cRDT had poor sensitivity for active case detection in asymptomatic community members, and sensitivity was lowest in highly prevalent low-density infections and in adults. Future studies can model the incremental effects of high-sensitivity rapid diagnostic tests and the impacts on transmission.
以常规快速诊断检测（cRDT）进行基于社区的疟疾寄生虫主动病例检测是在低传播环境中最常用的策略。我们评估了在肯尼亚西部高传播环境中该方法的敏感性。我们于 2013-2014 年通过索引儿童检测到 912 户家庭中的 3547 名成员，他们的 cRDT 检测结果为阳性（病例）和阴性（对照）的疟疾。所有人均接受了针对组氨酸丰富蛋白 2 的 cRDT 以及超敏实时聚合酶链反应（PCR）检测。我们将 cRDT 对 PCR 的敏感性作为参考，比较参与者类型之间的患病率，并根据 PCR 估计的寄生虫密度来估计 cRDT 的可检测性。cRDT 的寄生虫患病率为 22.9%，PCR 为 61.5%。与年龄<5 岁的儿童或年龄>15 岁的成年人相比，年龄为 5-15 岁的学龄儿童的几何平均寄生虫密度（95%CI）最高（8.4 p/uL；6.6-10.6）。cRDT 的总体敏感性为 36%；在无症状的家庭成员中，cRDT 的敏感性为 25.5%，年龄>15 岁的成年人最低（15.8%）。当将其作为寄生虫密度的函数建模时，与学龄儿童相比，cRDT 阳性的可能性在年龄<5 岁的儿童（比值比 [OR]0.48；95%CI：0.34-0.69）和年龄>15 岁的成年人（OR：0.35；95%CI：0.27-0.47）中降低。HRP2 检测的 cRDT 对无症状社区成员的主动疟疾病例检测敏感性较差，在高流行低密度感染和成年人中敏感性最低。未来的研究可以对高灵敏度快速诊断检测的增量效果及其对传播的影响进行建模。
