Chieng Benard, Okoyo Collins, Simiyu Elses, Gichuki Paul, Mwatele Cassian, Kepha Stella, Njenga Sammy, Mburu David
Eastern & Southern Africa Centre of International Parasite Control (ESACIPAC), Kenya Medical Research Institute (KEMRI), PO BOX 54840-00200, Nairobi, Kenya.
Department of Microbiology, Biotechnology and Biochemistry, Kenyatta University, Nairobi, Kenya.
Curr Res Parasitol Vector Borne Dis. 2021 Jul 15;1:100029. doi: 10.1016/j.crpvbd.2021.100029. eCollection 2021.
The current standard diagnostic tests for are the Kato-Katz and circulating cathodic antigen (CCA) techniques. However, these techniques have been documented to have several limitations that have a direct impact on schistosomiasis control programmes. Therefore, there is a need for more sensitive and specific tests for diagnosing schistosomiasis. This study compared the performance of quantitative polymerase chain reaction (qPCR), Kato-Katz, and point-of-care circulating cathodic antigen (POC-CCA) techniques in the diagnosis of infection in the Mwea irrigation scheme, Kirinyaga County in Central Kenya. We carried out a cross-sectional study on 357 individuals residing in four villages in the Mwea irrigation scheme. The participants provided urine and stool samples which were screened for infections using the three techniques. The prevalence of by each technique was calculated and 95% confidence intervals estimated using binomial regression model. Sensitivity and specificity were determined using 2 × 2 contingency tables and compared using the McNemar's chi-square test. Positive and negative predictive values were also determined using the weighted generalized score chi-square test for paired data. The study showed that the prevalence of was 32.8%, 62.5% and 72.8% using Kato-Katz, POC-CCA and qPCR techniques, respectively. Further, when using Kato-Katz as a gold standard, POC-CCA sensitivity was 78.6% and specificity was 45.4%, while qPCR sensitivity was 97.4% and specificity was 39.2%. When using qPCR as the gold standard, Kato-Katz sensitivity was 43.8% and specificity was 96.9%, while POC-CCA sensitivity was 78.1% and specificity was 79.4%. Finally, when using the averaged results from the three techniques as the gold standard, the sensitivity was 41.6%, 79.4% and 92.5% for Kato-Katz, POC-CCA and qPCR, respectively, with a specificity of 100% for all techniques. Kato-Katz technique showed low sensitivity compared to the POC-CCA and qPCR despite it being the most commonly preferred method of choice to diagnose infections. qPCR showed superior sensitivity followed by POC-CCA, hence it can be used as an alternative or to confirm the results obtained by the Kato-Katz technique.
目前用于[疾病名称未明确，推测为血吸虫病]的标准诊断测试是加藤厚涂片法（Kato-Katz法）和循环阴极抗原（CCA）检测技术。然而，这些技术存在一些局限性，已被记录在案，这对血吸虫病防治计划产生了直接影响。因此，需要更灵敏、特异的血吸虫病诊断测试。本研究比较了定量聚合酶链反应（qPCR）、加藤厚涂片法（Kato-Katz法）和即时检测循环阴极抗原（POC-CCA）技术在肯尼亚中部基里尼亚加县姆韦亚灌溉区诊断[疾病名称未明确，推测为血吸虫病]感染中的表现。我们对居住在姆韦亚灌溉区四个村庄的357人进行了横断面研究。参与者提供了尿液和粪便样本，使用这三种技术对样本进行[疾病名称未明确，推测为血吸虫病]感染筛查。计算每种技术检测[疾病名称未明确，推测为血吸虫病]的患病率，并使用二项式回归模型估计95%置信区间。使用2×2列联表确定敏感性和特异性，并使用McNemar卡方检验进行比较。还使用配对数据的加权广义得分卡方检验确定阳性和阴性预测值。研究表明，使用加藤厚涂片法（Kato-Katz法）、即时检测循环阴极抗原（POC-CCA）和qPCR技术检测[疾病名称未明确，推测为血吸虫病]的患病率分别为32.8%、62.5%和72.8%。此外，以加藤厚涂片法（Kato-Katz法）作为金标准时，即时检测循环阴极抗原（POC-CCA）的敏感性为78.6%，特异性为45.4%，而qPCR的敏感性为97.4%，特异性为39.2%。以qPCR作为金标准时，加藤厚涂片法（Kato-Katz法）的敏感性为43.8%，特异性为96.9%，而即时检测循环阴极抗原（POC-CCA）的敏感性为78.1%，特异性为79.4%。最后，以三种技术的平均结果作为金标准时，加藤厚涂片法（Kato-Katz法）、即时检测循环阴极抗原（POC-CCA）和qPCR的敏感性分别为41.6%、79.4%和92.5%，所有技术的特异性均为100%。尽管加藤厚涂片法（Kato-Katz法）是诊断[疾病名称未明确，推测为血吸虫病]感染最常用的首选方法，但与即时检测循环阴极抗原（POC-CCA）和qPCR相比，其敏感性较低。qPCR的敏感性最高，其次是即时检测循环阴极抗原（POC-CCA），因此它可以用作替代方法或用于确认加藤厚涂片法（Kato-Katz法）获得的结果。
