Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, PO Box 66, 00014, Helsinki, Finland.
Food Environ Virol. 2018 Mar;10(1):51-60. doi: 10.1007/s12560-017-9321-5. Epub 2017 Oct 10.
Raspberries have lately caused several human norovirus (HuNoV) outbreaks in Europe. In this study, we developed and evaluated for HuNoV reverse transcription (RT)-PCR detection in frozen raspberries extraction methods that have equal sensitivity but are less time-consuming than widely used methods based on polyethylene glycol (PEG) precipitation and chloroform-butanol purification. One method was applied to stored frozen raspberries linked to previous HuNoV outbreaks and berries on sale. In the virus elution-based Method 1, sparkling water eluted viruses most efficiently from the berries. Method 2, based on direct nucleic acid extraction with minor PEG supplement, yielded the highest number of positive findings (4 out of 9) at low virus concentration level of 100 genome copies HuNoV genogroup II per 25 g raspberries. Both methods showed approximately equal sensitivity to a method including PEG precipitation and chloroform-butanol purification. Two naturally contaminated berry samples linked to HuNoV outbreaks in 2006 and 2009 were still positive for HuNoV genogroup I, but all berry products purchased from a local store remained negative for HuNoV. In conclusion, this study presents two efficient and rapid methods which can be used in urgent HuNoV outbreak investigations, since the results of the virus analysis are available in a few hours.
最近，覆盆子在欧洲引发了几起人类诺如病毒（HuNoV）暴发事件。在这项研究中，我们开发并评估了用于冷冻覆盆子提取的 HuNoV 逆转录（RT）-PCR 检测方法，这些方法与基于聚乙二醇（PEG）沉淀和氯仿-丁醇纯化的广泛使用方法相比，具有相同的灵敏度，但耗时更短。其中一种方法应用于与先前 HuNoV 暴发事件相关的储存冷冻覆盆子和销售中的浆果。在基于病毒洗脱的方法 1 中， sparkling water 从浆果中洗脱病毒的效率最高。方法 2 基于用少量 PEG 补充的直接核酸提取，在低病毒浓度水平下（每 25 g 覆盆子中有 100 个基因组拷贝 HuNoV 基因组 II），获得了最高数量的阳性结果（4 个中有 9 个）。两种方法的灵敏度与包括 PEG 沉淀和氯仿-丁醇纯化的方法大致相同。与 2006 年和 2009 年 HuNoV 暴发事件相关的两个天然污染浆果样本仍对 HuNoV 基因组 I 呈阳性，但从当地一家商店购买的所有浆果产品均对 HuNoV 呈阴性。总之，本研究提出了两种高效快速的方法，可用于紧急 HuNoV 暴发调查，因为病毒分析的结果可在数小时内获得。
