Microbiological Testing and Research Division, Yokohama City Institute of Public Health, Yokohama, Japan
Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan.
Appl Environ Microbiol. 2019 Nov 27;85(24). doi: 10.1128/AEM.01604-19. Print 2019 Dec 15.
Environmental surveillance can be used to trace enteroviruses shed from human stool using a sewer network that is independent of symptomatic or asymptomatic infection. In this study, the local transmission of enteroviruses was analyzed using two wastewater treatment plants, which were relatively close to each other (15 km), designated as sentinels. Influent was collected at both sentinels once a month from 2013 to 2016, and viruses were isolated. Using neutralizing tests with type-specific polyclonal antisera and molecular typing, 933 isolates were identified as enteroviruses. Our results showed that the frequency of virus isolation varied for each serotype at the two sentinels in a time-dependent manner. Because echovirus 11 (Echo11) and coxsackievirus B5 isolates showed a high frequency and were difficult to distinguish, they were further grouped into various lineages based on the VP1 amino acid sequences. The prevalence of each lineage was visualized using multidimensional scaling. The results showed that Echo11 isolates of the same lineage were isolated continuously, similar to coxsackievirus B5 isolates of three lineages. Conversely, Echo1, Echo13, Echo18, Echo19, Echo20, Echo29, and Echo33 were isolated only once each. Our findings suggested that if an enterovirus is imported into the population, it may result in small-scale transmission, whereas if there are initially many infected individuals, it may be possible for the virus to spread to a wide area, beyond the local community, over time. In addition, our findings could provide insights into risk assessment of transmission for importation of poliovirus in polio-free countries and regions. In this study, we showed that environmental enterovirus surveillance can be used to monitor the propagation of nonpolio enteroviruses in addition to poliovirus detection. Since epidemiological studies of virus transmission based on the past were performed using specimens from humans, there were limitations to research design, such as specimen collection for implementation on a large-scale target population. However, environmental monitoring can dynamically track the ecological changes in enteroviruses in the region by monitoring viruses in chronological order and targeting the population within the area by monitoring viruses over time. We observed differences in the transmission of echovirus 11 and coxsackievirus B5 in the region according to lineage in a time-dependent manner and with a multidimensional scaling pattern.
环境监测可用于追踪通过独立于症状性或无症状性感染的下水道网络从人类粪便中排出的肠道病毒。在这项研究中，使用两个相对靠近（15 公里）的污水处理厂（被指定为哨点）分析肠道病毒的本地传播。2013 年至 2016 年，每月在两个哨点各采集一次进水，然后分离病毒。使用针对特定血清型的多克隆抗血清和分子分型进行中和试验，鉴定出 933 株肠道病毒为肠道病毒。我们的结果表明，在时间依赖性方面，两种血清型在两个哨点的病毒分离频率各不相同。由于柯萨奇病毒 B5 和肠道病毒 11（Echo11）的分离频率较高且难以区分，因此根据 VP1 氨基酸序列将它们进一步分为不同的谱系。使用多维缩放可视化每个谱系的流行率。结果表明，同一谱系的 Echo11 分离株连续分离，类似于三个谱系的柯萨奇病毒 B5 分离株。相反，Echo1、Echo13、Echo18、Echo19、Echo20、Echo29 和 Echo33 各仅分离一次。我们的研究结果表明，如果肠道病毒传入人群中，可能会导致小范围传播，而如果最初有许多感染者，则病毒可能会随着时间的推移传播到更广泛的区域，超出当地社区。此外，我们的研究结果还可以为评估无脊髓灰质炎国家和地区输入脊灰病毒的传播风险提供参考。在这项研究中，我们表明，除了检测脊灰病毒之外，环境肠道病毒监测还可用于监测非脊灰肠道病毒在当地的传播。由于基于过去的病毒传播的流行病学研究是使用人类标本进行的，因此研究设计存在局限性，例如在大规模目标人群中实施标本采集。但是，通过按时间顺序监测病毒并随着时间的推移针对该区域的人群监测病毒，环境监测可以动态跟踪该区域肠道病毒的生态变化。我们观察到，根据谱系，Echo11 和柯萨奇病毒 B5 在该地区的传播存在时间依赖性差异，并且具有多维缩放模式。
