Eastern and Southern Africa Centre of International Parasite Control (ESACIPAC), Kenya Medical Research Institute (KEMRI), Nairobi, Kenya.
FIND, Geneva, Switzerland.
PLoS One. 2024 Sep 20;19(9):e0310118. doi: 10.1371/journal.pone.0310118. eCollection 2024.
The microscopy-based Kato-Katz and urine filtration techniques have traditionally faced challenges in the detection of schistosomiasis in areas with low infection levels. A modified singleplex Schistosoma genus-specific quantitative real-time polymerase chain reaction (qPCR) assay was therefore evaluated as a sensitive and confirmatory schistosomiasis diagnostic test.
The qPCR assay utilized primers and probe targeting internal transcribed spacer- 2 (ITS2) sequence of S. mansoni, S. haematobium and S. intercalatum. A plasmid (pDMD801, 100pg/ul) was used as an internal amplification control and its qPCR assays were run in parallel to the Schistosoma assays. This assay utilized samples collected from 774 participants and microscopically examined for three consecutive days. A total of 699 day-one samples (urine and stools) from two schistosomiasis endemic sites were analyzed. Similarly, 75 persons from a non-endemic control site provided both urine and stool samples that were also analyzed.
Using microscopy, the proportion of positives in the two endemic regions altogether was 289/699 (41.3%). Using qPCR, 50.4% of the samples (352/699) were found to be positive for schistosome infection. The percentage of positive samples was slightly higher at 57.8% (203/351) in the S. mansoni endemic site compared with the S. haematobium site at 42.8% (149/348). Majority of the microscopy results were light infections at 26.8% (n = 94) and 26.1% (n = 91) while qPCR majority of the infections were high at 41.6% (n = 146) and 31.3% (n = 109) for the S. mansoni and S. haematobium sites, respectively. There were no positives detected by either microscopy or qPCR in the non-endemic site. Using Bayesian Latent Class Model, which does not use any technique as a gold standard, qPCR showed higher sensitivity (86.4% (PCI: 82.1-90.3)) compared to microscopy (75.6% (PCI: 71.1-80.0)).
This study documents a single day-one sample modified Schistosoma qPCR assay as a powerful improved molecular assay for the detection of schistosomiasis infection that utilize either stool or urine samples. The assay is therefore recommended for monitoring in areas with low infection levels to enable accurate determination of the disease's control endpoint.
基于显微镜的加藤加藤和尿液过滤技术在检测低感染水平地区的血吸虫病时一直面临挑战。因此，评估了一种改良的单重曼氏血吸虫属特异性定量实时聚合酶链反应（qPCR）检测作为一种敏感和确认性血吸虫病诊断检测。
qPCR 检测利用针对曼氏血吸虫、埃及血吸虫和间插血吸虫内部转录间隔区 2（ITS2）序列的引物和探针。质粒（pDMD801，100pg/μl）用作内部扩增对照，其 qPCR 检测与血吸虫检测平行运行。该检测利用从 774 名参与者采集的样本，并连续三天进行显微镜检查。总共分析了来自两个血吸虫病流行地区的 699 名第一天样本（尿液和粪便）。同样，来自非流行控制地点的 75 人提供了尿液和粪便样本，也进行了分析。
使用显微镜，两个流行地区的总阳性比例为 289/699（41.3%）。使用 qPCR，发现 50.4%（352/699）的样本对血吸虫感染呈阳性。在曼氏血吸虫流行地区，阳性样本的比例略高，为 57.8%（203/351），而在埃及血吸虫流行地区为 42.8%（149/348）。大多数显微镜结果为轻度感染，分别为 26.8%（n=94）和 26.1%（n=91），而 qPCR 感染的大多数为高感染，分别为 41.6%（n=146）和 31.3%（n=109）对于曼氏血吸虫和埃及血吸虫地点。非流行地区未检测到任何技术的阳性结果。使用不将任何技术用作金标准的贝叶斯潜在类别模型，qPCR 显示出较高的敏感性（86.4%（PCI：82.1-90.3）），而显微镜检查为 75.6%（PCI：71.1-80.0）。
本研究记录了一种基于一天样本的改良曼氏血吸虫 qPCR 检测作为一种强大的改进分子检测方法，可用于检测血吸虫病感染，该方法可利用粪便或尿液样本。因此，建议在低感染水平地区进行监测，以准确确定疾病的控制终点。
