Knopp Stefanie, Corstjens Paul L A M, Koukounari Artemis, Cercamondi Colin I, Ame Shaali M, Ali Said M, de Dood Claudia J, Mohammed Khalfan A, Utzinger Jürg, Rollinson David, van Dam Govert J
Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, London, United Kingdom; Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland.
Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands.
PLoS Negl Trop Dis. 2015 May 14;9(5):e0003752. doi: 10.1371/journal.pntd.0003752. eCollection 2015 May.
Elimination of schistosomiasis as a public health problem and interruption of transmission in selected areas are key goals of the World Health Organization for 2025. Conventional parasitological methods are insensitive for the detection of light-intensity infections. Techniques with high sensitivity and specificity are required for an accurate diagnosis in low-transmission settings and verification of elimination. We determined the accuracy of a urine-based up-converting phosphor-lateral flow circulating anodic antigen (UCP-LF CAA) assay for Schistosoma haematobium diagnosis in low-prevalence settings in Zanzibar, Tanzania.
A total of 1,740 urine samples were collected in 2013 from children on Pemba Island, from schools where the S. haematobium prevalence was <2%, 2-5%, and 5-10%, based on a single urine filtration. On the day of collection, all samples were tested for microhematuria with reagent strips and for the presence of S. haematobium eggs with microscopy. Eight months later, 1.5 ml of urine from each of 1,200 samples stored at -20°C were analyzed by UCP-LF CAA assay, while urine filtration slides were subjected to quality control (QCUF). In the absence of a true 'gold' standard, the diagnostic performance was calculated using latent class analyses (LCA).
The 'empirical' S. haematobium prevalence revealed by UCP-LF CAA, QCUF, and reagent strips was 14%, 5%, and 4%, respectively. LCA revealed a sensitivity of the UCP-LF CAA, QCUF, and reagent strips of 97% (95% confidence interval (CI): 91-100%), 86% (95% CI: 72-99%), and 67% (95% CI: 52-81%), respectively. Test specificities were consistently above 90%.
CONCLUSIONS/SIGNIFICANCE: The UCP-LF CAA assay shows high sensitivity for the diagnosis of S. haematobium in low-endemicity settings. Empirically, it detects a considerably higher number of infections than microscopy. Hence, the UCP-LF CAA employed in combination with QCUF, is a promising tool for monitoring and surveillance of urogenital schistosomiasis in low-transmission settings targeted for elimination.
消除血吸虫病这一公共卫生问题并在特定地区阻断传播是世界卫生组织2025年的关键目标。传统寄生虫学方法对轻度感染检测不敏感。在低传播环境中进行准确诊断和验证消除情况需要高灵敏度和特异性的技术。我们确定了基于尿液的上转换磷光侧向流动循环阳极抗原（UCP-LF CAA）检测法在坦桑尼亚桑给巴尔低流行环境中诊断埃及血吸虫病的准确性。
2013年从奔巴岛的儿童中总共收集了1740份尿液样本，这些儿童来自埃及血吸虫病患病率分别<2%、2 - 5%和5 - 10%的学校，基于单次尿液过滤。在收集当天，所有样本用试纸条检测微量血尿，并通过显微镜检查检测埃及血吸虫卵的存在。八个月后，对储存在-20°C的1200份样本中的每份样本取1.5 ml尿液进行UCP-LF CAA检测分析，同时对尿液过滤玻片进行质量控制（QCUF）。在没有真正“金标准”的情况下，使用潜在类别分析（LCA）计算诊断性能。
UCP-LF CAA、QCUF和试纸条显示的埃及血吸虫病“经验性”患病率分别为14%、5%和4%。LCA显示UCP-LF CAA、QCUF和试纸条的灵敏度分别为97%（95%置信区间（CI）：91 - 100%）、86%（95% CI：72 - 99%）和67%（95% CI：52 - 81%）。检测特异性始终高于90%。
结论/意义：UCP-LF CAA检测法在低流行环境中对埃及血吸虫病诊断显示出高灵敏度。根据经验，它检测到的感染病例数比显微镜检查多得多。因此，UCP-LF CAA与QCUF联合使用，是在以消除为目标的低传播环境中监测泌尿生殖系统血吸虫病的一种有前景的工具。
