Thakur Mamta, Mewara Abhishek, Lakshmi Pvm, Guleria Sucheta, Khurana Sumeeta
Department of Medical Parasitology, Post Graduate Institute of Medical Education and Research, Chandigarh.
Department of Community Medicine and School of Public Health, Post Graduate Institute of Medical Education and Research, Chandigarh.
Diagn Microbiol Infect Dis. 2025 Jul;112(3):116808. doi: 10.1016/j.diagmicrobio.2025.116808. Epub 2025 Mar 20.
Ascariasis, caused by Ascaris lumbricoides, is a widespread parasitic infection. Traditional diagnostic methods, such as microscopy, can miss infections with low worm burdens, leading to false negatives. This study compares four diagnostic methods-microscopy, conventional PCR, real-time PCR, and loop-mediated isothermal amplification (LAMP)-for detecting A. lumbricoides in 400 stool samples from children aged 2-16. Microscopy methods (direct wet mount, Kato-Katz, and concentration) detected 17, 23, and 21 positive samples, respectively. Molecular techniques identified 23 positive samples by conventional PCR, 29 by real-time PCR, and 25 by LAMP. Notably, real-time PCR detected two samples missed by microscopy, while conventional PCR failed to detect three samples positive by real-time PCR and LAMP. In limit-of-detection assays, conventional PCR detected A. lumbricoides DNA down to 150 pg, while qPCR and LAMP could detect as low as 15 fg. For egg number analysis, conventional PCR detected DNA from 100 eggs, while qPCR and LAMP identified DNA from just 10 eggs. The methods specifically targeted A. lumbricoides, without cross-reacting with other co-occurring parasites. Sensitivity and specificity analysis revealed that microscopy had sensitivities of 81.3 %, while conventional PCR, qPCR, and LAMP had sensitivities of 81.1 %, 99.2 %, and 88.1 %, respectively. Microscopy and conventional PCR had 100 % specificity, while qPCR and LAMP had 99.2 % and 99.9 % specificity. While Kato-Katz is advantageous for detecting active infections, molecular techniques, particularly LAMP's field applicability in resource-limited settings makes it a promising tool for surveillance and control of low-intensity infections.
由蛔虫引起的蛔虫病是一种广泛传播的寄生虫感染。传统的诊断方法，如显微镜检查，可能会漏诊蠕虫负荷低的感染，导致假阴性结果。本研究比较了四种诊断方法——显微镜检查、常规聚合酶链反应（PCR）、实时PCR和环介导等温扩增技术（LAMP）——用于检测400份2至16岁儿童粪便样本中的蛔虫。显微镜检查方法（直接湿片法、加藤厚涂片法和浓缩法）分别检测出17、23和21份阳性样本。分子技术通过常规PCR鉴定出23份阳性样本，实时PCR鉴定出29份，LAMP鉴定出25份。值得注意的是，实时PCR检测出了显微镜检查漏诊的两份样本，而常规PCR未能检测出实时PCR和LAMP检测为阳性的三份样本。在检测限分析中，常规PCR可检测低至150皮克的蛔虫DNA，而定量PCR（qPCR）和LAMP可低至15飞克。对于虫卵数量分析，常规PCR可检测到100个虫卵的DNA，而qPCR和LAMP仅能鉴定出10个虫卵的DNA。这些方法特异性针对蛔虫，不与其他同时存在的寄生虫发生交叉反应。敏感性和特异性分析显示，显微镜检查的敏感性为81.3%，而常规PCR、qPCR和LAMP的敏感性分别为81.1%、99.2%和88.1%。显微镜检查和常规PCR的特异性为100%，而qPCR和LAMP的特异性分别为99.2%和99.9%。虽然加藤厚涂片法在检测活动性感染方面具有优势，但分子技术，特别是LAMP在资源有限环境中的现场适用性使其成为监测和控制低强度感染的有前途的工具。
