Science Division, Biology Department, Swedish Food Agency, Hamnesplanaden 5, 75319, Uppsala, Sweden.
Department of Surgical and Perioperative Sciences, Surgery, Umeå University, Umeå, Sweden.
Food Environ Virol. 2021 Sep;13(3):380-389. doi: 10.1007/s12560-021-09477-x. Epub 2021 May 11.
Concentration of viruses in water is necessary for detection and quantification of the viruses present, in order to evaluate microbiological barriers in water treatment plants and detect pathogenic viruses during waterborne outbreaks, but there is currently no standardised procedure. In this study, we implemented a previously described fast and simple lanthanum-based protocol for concentration of norovirus genogroup I (GI), genogroup II (GII) and hepatitis A virus (HAV) in drinking and surface water. We compared the results with those of a widely used skimmed milk flocculation method, followed by nucleic acid extraction and RT-qPCR detection. Three seeding levels, with intended concentrations 5 × 10, 5 × 10 and 5 × 10 genome copies/10 L, were added to drinking water or surface water. All seed levels were detected with both flocculation methods. Samples extracted with skimmed milk flocculation had on average 1.82, 1.86 and 1.38 times higher measured concentration of norovirus GI, GII and HAV, respectively, than those extracted with lanthanum flocculation, across all seeding levels and water types tested. Mengovirus was used as a positive process control. Mengovirus recovery was higher for skimmed milk (40.7% in drinking water, 26.0% in surface water) than for lanthanum flocculation (24.4% in drinking water, 9.7% in surface water). Together, this indicates that skimmed milk flocculation provides higher viral recovery than lanthanum flocculation. However, lanthanum-based flocculation can be performed much faster than skimmed milk flocculation (1.5 h versus 16 h flocculation time) and thus could be a good alternative for rapid monitoring of viruses in water.
病毒在水中的浓度对于检测和量化存在的病毒是必要的，以便评估水处理厂中的微生物屏障，并在水传播暴发期间检测致病病毒，但目前还没有标准化的程序。在这项研究中，我们采用了先前描述的一种快速简便的基于镧的方法，用于浓缩饮用水和地表水中的诺如病毒基因组 I（GI）、基因组 II（GII）和甲型肝炎病毒（HAV）。我们将结果与广泛使用的脱脂乳絮凝方法进行了比较，随后进行核酸提取和 RT-qPCR 检测。在饮用水或地表水中加入三个接种水平，预期浓度分别为 5×10、5×10 和 5×10 基因组拷贝/10 L。两种絮凝方法均能检测到所有接种水平。用脱脂乳絮凝法提取的样品的平均浓度分别比用镧絮凝法提取的样品高 1.82、1.86 和 1.38 倍，用于 GI、GII 和 HAV 诺如病毒，所有接种水平和测试的水样均如此。肠道病毒被用作阳性过程对照。在饮用水（40.7%）和地表水中（26.0%），用脱脂乳絮凝的肠道病毒回收率高于用镧絮凝的回收率（饮用水中为 24.4%，地表水中为 9.7%）。综上所述，这表明脱脂乳絮凝法比镧絮凝法提供更高的病毒回收率。然而，基于镧的絮凝法比脱脂乳絮凝法快得多（絮凝时间为 1.5 小时，而脱脂乳絮凝时间为 16 小时），因此可以作为水中病毒快速监测的一种很好的替代方法。
