Pulkkila Brittany, Sikasunge Chummy, Mwansa James, Lodh Nilanjan
Department of Medical Laboratory Science, Marquette University, Milwaukee, WI, United States of America.
Department of Para-clinical Studies, The University of Zambia, Lusaka, Zambia.
BMC Infect Dis. 2025 Sep 22;25(1):1114. doi: 10.1186/s12879-025-11370-y.
Schistosomiasis in Africa is an ongoing public health problem that is caused by two major human species, Schistosoma mansoni and S. haematobium, which often cause concurrent infections. Due to the global goal of controlling or eliminating schistosomiasis as a public health problem, the issue of diagnostic sensitivity has become more critical in the assessment of program success. In that regard, the World Health Organization (WHO) has drawn attention to the need for field-applicable tests with high specificity and sensitivity.
To address this, we have evaluated the amplification of S. mansoni and S. haematobium cell-free repeat DNA by loop-mediated isothermal amplification (LAMP) from field-collected filtered urine samples from 30 school children in Zambia. We have used four DNA extraction techniques (Qiagen and LAMP-PURE (LP): column-based DNA extraction technique, Chelex, and heating: rapid DNA extraction technique) to determine their impact on LAMP sensitivity and specificity, along with cost analysis and person-time involvement for each approach.
Both Qiagen and LP extraction detected positive infections, but Qiagen extraction is more cost-effective than LP. DNA extraction by LP is the fastest (average 20 min.) compared to the other three methods, although it is the most expensive, including amplification ($9.35 compared to $4.90 for heating extraction and amplification). Chelex extraction is slower and simpler than LP and detects 20% more positive infections than heating. Heating extraction is very fast, inexpensive, and simple to perform. However, LAMP amplification for heating-extracted samples resulted in false negatives, possibly indicating the presence of inhibitor(s).
We have demonstrated the sensitivity, cost-effectiveness, and time requirement of LAMP with four different DNA extraction approaches for the detection of two schistosome parasite species from a single field-collected urine sample.
非洲的血吸虫病是一个持续存在的公共卫生问题，由两种主要的人体血吸虫——曼氏血吸虫和埃及血吸虫引起，这两种血吸虫常导致合并感染。由于全球控制或消除血吸虫病这一公共卫生问题的目标，诊断敏感性问题在评估项目成功与否时变得更加关键。在这方面，世界卫生组织（WHO）已提请注意需要具有高特异性和敏感性且适用于现场的检测方法。
为解决这一问题，我们通过环介导等温扩增（LAMP）技术，对赞比亚30名学童现场采集的过滤尿液样本中曼氏血吸虫和埃及血吸虫无细胞重复DNA的扩增情况进行了评估。我们使用了四种DNA提取技术（Qiagen和LAMP-PURE（LP）：基于柱的DNA提取技术、Chelex和加热：快速DNA提取技术）来确定它们对LAMP敏感性和特异性的影响，同时对每种方法进行成本分析和人员时间投入分析。
Qiagen和LP提取法均检测到了阳性感染，但Qiagen提取法比LP更具成本效益。与其他三种方法相比，LP提取DNA的速度最快（平均20分钟），不过它也是最昂贵的，包括扩增成本（加热提取和扩增为4.90美元，而LP提取和扩增为9.35美元）。Chelex提取法比LP提取法慢且更简单，检测到的阳性感染比加热提取法多20%。加热提取法非常快速、便宜且操作简单。然而，加热提取样本的LAMP扩增产生了假阴性结果，这可能表明存在抑制剂。
我们通过四种不同的DNA提取方法，展示了LAMP从单个现场采集的尿液样本中检测两种血吸虫寄生虫的敏感性、成本效益和时间要求。
