Virus Reference Department, National Infections Service, Public Health England, London, UK.
Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK.
Int J Food Microbiol. 2021 Jun 16;348:109151. doi: 10.1016/j.ijfoodmicro.2021.109151. Epub 2021 Mar 11.
Foodborne outbreaks associated with transmission of norovirus are increasingly becoming a public health concern. Foods can be contaminated with faecal material at the point of production or during food preparation, in both the home and in commercial premises. Transmission of norovirus occurs through the faecal-oral route, either via person-to-person contact or through faecal-contamination of food, water, or environmental surfaces. Understanding the role and pathways of norovirus transmission - either via food handlers' hands, contaminated foods or the environment - remains a key public health priority to reduce the burden of norovirus-associated gastroenteritis. However the proportion of norovirus that is typically transferred remains unknown. Understanding this is necessary to estimate the risk of infection and the burden of gastroenteritis caused by norovirus. In this paper we present a novel method of capture, concentration and molecular detection of norovirus from a wider range of complex food matrices than those demonstrated in existing published methods. We demonstrate that this method can be used as a tool to detect and quantify norovirus from naturally contaminated food, and for monitoring norovirus transfer between food handlers' gloved hands, food or the environment. We measure the effect of introducing contamination at different food production process stages, to the final food product, to determine whether this could cause infection and disease. Between 5.9 and 6.3 Log cDNA copies/μl of norovirus GII were inoculated onto food handlers' gloved hands, food or the environment and 1.1-7.4% of norovirus contamination was recovered from all samples tested. When interpreted quantitatively, this percentage equates to levels predicted to be sufficient to cause infection and disease through consumption of the final food product, demonstrating a public health risk. Overall detection and quantification of norovirus from foods, food handlers' gloved hands and the environment, when suspected to be implicated in foodborne transmissions, is paramount for appropriate outbreak investigation.
食源性诺如病毒暴发越来越引起公众健康关注。食物在生产或家庭和商业场所准备过程中都可能被粪便物质污染。诺如病毒通过粪-口途径传播，无论是通过人与人之间的接触还是通过食物、水或环境表面的粪便污染。了解诺如病毒传播的作用和途径，无论是通过食品处理者的手、污染的食物还是环境，仍然是减少诺如病毒相关性胃肠炎负担的一个关键公共卫生重点。然而，通常转移的诺如病毒比例尚不清楚。了解这一点对于估计感染风险和由诺如病毒引起的胃肠炎负担是必要的。在本文中，我们提出了一种从比现有已发表方法中展示的更广泛的复杂食物基质中捕获、浓缩和分子检测诺如病毒的新方法。我们证明，该方法可用于检测和定量从自然污染食物中检测诺如病毒，并监测食品处理者手套、食物或环境之间的诺如病毒转移。我们测量了在不同的食品生产过程阶段引入污染到最终食品产品中的效果，以确定这是否会导致感染和疾病。将 5.9 至 6.3 Log cDNA 拷贝/μl 的诺如病毒 GII 接种到食品处理者的手套、食物或环境中，从所有测试的样本中回收了 1.1-7.4%的诺如病毒污染。从定量角度解释，这一比例相当于足以通过食用最终食品产品引起感染和疾病的水平，这表明存在公共卫生风险。在怀疑与食源性传播有关时，对食品、食品处理者手套和环境中的诺如病毒进行全面检测和定量，对于适当的暴发调查至关重要。
