Department of Epidemiology, College of Public Health, University of Nebraska Medical Center, Omaha, Nebraska, United States of America.
Department of Translational Physiology, Infectiology and Public Health, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
PLoS Negl Trop Dis. 2024 Aug 22;18(8):e0012435. doi: 10.1371/journal.pntd.0012435. eCollection 2024 Aug.
This study compared the clinical sensitivity and the time-to-result of an individual testing (IT) and a cascaded pooled testing approach (CPT; a positive test result in a pooled sample triggers examination of smaller-sized pools or individual samples) for assessing the prevalence and the intensity of Schistosoma haematobium infection. We also compared the sensitivity of the CPT in detecting S. haematobium infection when deploying urine filtration microscopy (UFM) vs. urine reagent strips (URS), and testing 10 mL vs. 15 mL of urine.
METHODOLOGY/PRINCIPAL FINDINGS: Between October 2021 and April 2022, S. haematobium eggs were counted in urine samples collected from school-aged children living in the Afar and Gambella Regional States of Ethiopia. Urine samples were collected at baseline (n = 1,288), and one month after administration of praziquantel (n = 118). All urine samples were processed through both an IT and a CPT approach (pools of 5, 10, 20, and 40 individual samples), deploying UFM (10 mL) and URS (10 mL). In addition, 15 mL urine was processed through the CPT deploying UFM. At baseline, the prevalence of S. haematobium infection estimated when using UFM and deploying a CPT approach was significantly lower (17.3%) compared to an IT approach (31.5%). The clinical sensitivity of the CPT in detecting S. haematobium eggs was 51.7%. The sensitivity increased significantly as a function of increasing log transformed urine egg counts (UECs) of the individual samples (OR 2.71, 95%CI 1.63 - 4.52). The sensitivity was comparable when the amount of urine examined was 10 mL (51.7%) vs. 15 ml (50.8%), and when UFM was used for testing vs. URS (51.5%). The mean log UECs estimated following the CPT approach was lower compared to the estimate by the IT (p <0.001). UECs of the individual samples estimated using the IT and CPT approaches were moderately correlated (r = 0.59 when 10 mL and 15 mL urine was examined after pooling). CPT reduced the time needed for processing urine samples and testing for S. haematobium infection by 29% with UFM and by 27.7% with URS.
CONCLUSIONS/SIGNIFICANCE: CPT based on UFM and URS techniques may help to rapidly identify areas with higher prevalence of S. haematobium infection (hotspots) in a population. However, the performance of this approach in estimating the prevalence of infection may be compromised, particularly in endemic areas with low intensity infection.
本研究比较了个体检测（IT）和级联 pooled 检测方法（CPT）在评估曼氏血吸虫感染的流行率和强度方面的临床敏感性和结果时间。我们还比较了 CPT 在使用尿液过滤显微镜（UFM）与尿液试剂条（URS）检测时、检测 10 毫升与 15 毫升尿液时检测曼氏血吸虫感染的敏感性。
方法/主要发现：2021 年 10 月至 2022 年 4 月，在埃塞俄比亚阿法尔和甘贝拉地区的学龄儿童中采集尿液样本，计算曼氏血吸虫卵数。基线时（n=1288）和服用吡喹酮一个月后（n=118）采集尿液样本。所有尿液样本均采用 IT 和 CPT 方法（5、10、20 和 40 个个体样本的池）处理，使用 UFM（10 毫升）和 URS（10 毫升）。此外，还使用 UFM 处理了 15 毫升尿液的 CPT。基线时，使用 UFM 和 CPT 方法估计的曼氏血吸虫感染流行率明显低于 IT 方法（17.3%比 31.5%）。CPT 检测曼氏血吸虫卵的临床灵敏度为 51.7%。随着个体样本尿液虫卵计数（UEC）的对数转换值的增加，灵敏度显著增加（OR 2.71，95%CI 1.63-4.52）。当检测的尿液量为 10 毫升（51.7%）与 15 毫升（50.8%）时，以及使用 UFM 与 URS 时，灵敏度相当（51.5%）。与 IT 相比，CPT 方法估计的平均 UEC 较低（p<0.001）。使用 IT 和 CPT 方法估计的个体样本 UEC 中度相关（当对 10 毫升和 15 毫升尿液进行 pooling 后，r=0.59）。CPT 使 UFM 和 URS 检测曼氏血吸虫感染的处理时间分别缩短了 29%和 27.7%。
结论/意义：基于 UFM 和 URS 技术的 CPT 可能有助于快速识别人群中曼氏血吸虫感染的高流行率（热点）地区。然而，这种方法在估计感染流行率方面的性能可能会受到影响，特别是在感染强度较低的流行地区。
